mirror of
https://sourceware.org/git/glibc.git
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8f8dd904c4
For a long time, libc.so.6 has dependend on ld.so, which means that there is a reference to ld.so in all processes, and rtld_multiple_ref is always true. In fact, if rtld_multiple_ref were false, some of the ld.so setup code would not run. Reviewed-by: DJ Delorie <dj@redhat.com>
2832 lines
86 KiB
C
2832 lines
86 KiB
C
/* Run time dynamic linker.
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Copyright (C) 1995-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <dlfcn.h>
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#include <fcntl.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <ldsodefs.h>
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#include <_itoa.h>
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#include <entry.h>
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#include <fpu_control.h>
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#include <hp-timing.h>
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#include <libc-lock.h>
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#include <unsecvars.h>
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#include <dl-cache.h>
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#include <dl-osinfo.h>
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#include <dl-procinfo.h>
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#include <dl-prop.h>
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#include <dl-vdso.h>
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#include <dl-vdso-setup.h>
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#include <tls.h>
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#include <stap-probe.h>
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#include <stackinfo.h>
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#include <not-cancel.h>
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#include <array_length.h>
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#include <libc-early-init.h>
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#include <dl-main.h>
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#include <gnu/lib-names.h>
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#include <dl-tunables.h>
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#include <get-dynamic-info.h>
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#include <dl-execve.h>
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#include <dl-find_object.h>
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#include <dl-audit-check.h>
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#include <dl-call_tls_init_tp.h>
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#include <assert.h>
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/* This #define produces dynamic linking inline functions for
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bootstrap relocation instead of general-purpose relocation.
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Since ld.so must not have any undefined symbols the result
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is trivial: always the map of ld.so itself. */
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#define RTLD_BOOTSTRAP
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#define RESOLVE_MAP(map, scope, sym, version, flags) map
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#include "dynamic-link.h"
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/* Must include after <dl-machine.h> for DT_MIPS definition. */
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#include <dl-debug.h>
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/* Only enables rtld profiling for architectures which provides non generic
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hp-timing support. The generic support requires either syscall
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(clock_gettime), which will incur in extra overhead on loading time.
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Using vDSO is also an option, but it will require extra support on loader
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to setup the vDSO pointer before its usage. */
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#if HP_TIMING_INLINE
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# define RLTD_TIMING_DECLARE(var, classifier,...) \
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classifier hp_timing_t var __VA_ARGS__
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# define RTLD_TIMING_VAR(var) RLTD_TIMING_DECLARE (var, )
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# define RTLD_TIMING_SET(var, value) (var) = (value)
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# define RTLD_TIMING_REF(var) &(var)
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static inline void
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rtld_timer_start (hp_timing_t *var)
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{
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HP_TIMING_NOW (*var);
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}
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static inline void
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rtld_timer_stop (hp_timing_t *var, hp_timing_t start)
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{
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hp_timing_t stop;
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HP_TIMING_NOW (stop);
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HP_TIMING_DIFF (*var, start, stop);
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}
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static inline void
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rtld_timer_accum (hp_timing_t *sum, hp_timing_t start)
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{
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hp_timing_t stop;
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rtld_timer_stop (&stop, start);
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HP_TIMING_ACCUM_NT(*sum, stop);
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}
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#else
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# define RLTD_TIMING_DECLARE(var, classifier...)
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# define RTLD_TIMING_SET(var, value)
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# define RTLD_TIMING_VAR(var)
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# define RTLD_TIMING_REF(var) 0
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# define rtld_timer_start(var)
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# define rtld_timer_stop(var, start)
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# define rtld_timer_accum(sum, start)
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#endif
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/* Avoid PLT use for our local calls at startup. */
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extern __typeof (__mempcpy) __mempcpy attribute_hidden;
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/* GCC has mental blocks about _exit. */
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extern __typeof (_exit) exit_internal asm ("_exit") attribute_hidden;
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#define _exit exit_internal
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/* Helper function to handle errors while resolving symbols. */
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static void print_unresolved (int errcode, const char *objname,
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const char *errsting);
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/* Helper function to handle errors when a version is missing. */
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static void print_missing_version (int errcode, const char *objname,
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const char *errsting);
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/* Print the various times we collected. */
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static void print_statistics (const hp_timing_t *total_timep);
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/* Creates an empty audit list. */
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static void audit_list_init (struct audit_list *);
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/* Add a string to the end of the audit list, for later parsing. Must
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not be called after audit_list_next. */
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static void audit_list_add_string (struct audit_list *, const char *);
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/* Add the audit strings from the link map, found in the dynamic
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segment at TG (either DT_AUDIT and DT_DEPAUDIT). Must be called
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before audit_list_next. */
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static void audit_list_add_dynamic_tag (struct audit_list *,
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struct link_map *,
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unsigned int tag);
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/* Extract the next audit module from the audit list. Only modules
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for which dso_name_valid_for_suid is true are returned. Must be
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called after all the audit_list_add_string,
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audit_list_add_dynamic_tags calls. */
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static const char *audit_list_next (struct audit_list *);
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/* Initialize *STATE with the defaults. */
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static void dl_main_state_init (struct dl_main_state *state);
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/* Process all environments variables the dynamic linker must recognize.
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Since all of them start with `LD_' we are a bit smarter while finding
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all the entries. */
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extern char **_environ attribute_hidden;
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static int process_envvars (struct dl_main_state *state);
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int _dl_argc attribute_relro attribute_hidden;
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char **_dl_argv attribute_relro = NULL;
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rtld_hidden_data_def (_dl_argv)
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#ifndef THREAD_SET_STACK_GUARD
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/* Only exported for architectures that don't store the stack guard canary
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in thread local area. */
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uintptr_t __stack_chk_guard attribute_relro;
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#endif
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/* Only exported for architectures that don't store the pointer guard
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value in thread local area. */
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uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden;
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#ifndef THREAD_SET_POINTER_GUARD
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strong_alias (__pointer_chk_guard_local, __pointer_chk_guard)
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#endif
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/* Check that AT_SECURE=0, or that the passed name does not contain
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directories and is not overly long. Reject empty names
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unconditionally. */
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static bool
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dso_name_valid_for_suid (const char *p)
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{
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if (__glibc_unlikely (__libc_enable_secure))
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{
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/* Ignore pathnames with directories for AT_SECURE=1
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programs, and also skip overlong names. */
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size_t len = strlen (p);
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if (len >= SECURE_NAME_LIMIT || memchr (p, '/', len) != NULL)
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return false;
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}
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return *p != '\0';
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}
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static void
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audit_list_init (struct audit_list *list)
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{
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list->length = 0;
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list->current_index = 0;
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list->current_tail = NULL;
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}
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static void
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audit_list_add_string (struct audit_list *list, const char *string)
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{
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/* Empty strings do not load anything. */
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if (*string == '\0')
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return;
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if (list->length == array_length (list->audit_strings))
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_dl_fatal_printf ("Fatal glibc error: Too many audit modules requested\n");
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list->audit_strings[list->length++] = string;
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/* Initialize processing of the first string for
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audit_list_next. */
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if (list->length == 1)
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list->current_tail = string;
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}
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static void
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audit_list_add_dynamic_tag (struct audit_list *list, struct link_map *main_map,
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unsigned int tag)
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{
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ElfW(Dyn) *info = main_map->l_info[ADDRIDX (tag)];
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const char *strtab = (const char *) D_PTR (main_map, l_info[DT_STRTAB]);
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if (info != NULL)
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audit_list_add_string (list, strtab + info->d_un.d_val);
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}
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static const char *
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audit_list_next (struct audit_list *list)
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{
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if (list->current_tail == NULL)
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return NULL;
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while (true)
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{
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/* Advance to the next string in audit_strings if the current
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string has been exhausted. */
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while (*list->current_tail == '\0')
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{
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++list->current_index;
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if (list->current_index == list->length)
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{
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list->current_tail = NULL;
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return NULL;
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}
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list->current_tail = list->audit_strings[list->current_index];
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}
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/* Split the in-string audit list at the next colon colon. */
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size_t len = strcspn (list->current_tail, ":");
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if (len > 0 && len < sizeof (list->fname))
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{
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memcpy (list->fname, list->current_tail, len);
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list->fname[len] = '\0';
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}
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else
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/* Mark the name as unusable for dso_name_valid_for_suid. */
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list->fname[0] = '\0';
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/* Skip over the substring and the following delimiter. */
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list->current_tail += len;
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if (*list->current_tail == ':')
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++list->current_tail;
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/* If the name is valid, return it. */
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if (dso_name_valid_for_suid (list->fname))
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return list->fname;
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/* Otherwise wrap around to find the next list element. . */
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}
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}
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/* Count audit modules before they are loaded so GLRO(dl_naudit)
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is not yet usable. */
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static size_t
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audit_list_count (struct audit_list *list)
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{
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/* Restore the audit_list iterator state at the end. */
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const char *saved_tail = list->current_tail;
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size_t naudit = 0;
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assert (list->current_index == 0);
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while (audit_list_next (list) != NULL)
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naudit++;
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list->current_tail = saved_tail;
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list->current_index = 0;
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return naudit;
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}
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static void
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dl_main_state_init (struct dl_main_state *state)
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{
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audit_list_init (&state->audit_list);
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state->library_path = NULL;
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state->library_path_source = NULL;
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state->preloadlist = NULL;
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state->preloadarg = NULL;
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state->glibc_hwcaps_prepend = NULL;
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state->glibc_hwcaps_mask = NULL;
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state->mode = rtld_mode_normal;
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state->version_info = false;
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}
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#ifndef HAVE_INLINED_SYSCALLS
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/* Set nonzero during loading and initialization of executable and
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libraries, cleared before the executable's entry point runs. This
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must not be initialized to nonzero, because the unused dynamic
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linker loaded in for libc.so's "ld.so.1" dep will provide the
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definition seen by libc.so's initializer; that value must be zero,
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and will be since that dynamic linker's _dl_start and dl_main will
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never be called. */
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int _dl_starting_up = 0;
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rtld_hidden_def (_dl_starting_up)
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#endif
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/* This is the structure which defines all variables global to ld.so
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(except those which cannot be added for some reason). */
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struct rtld_global _rtld_global =
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{
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/* Get architecture specific initializer. */
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#include <dl-procruntime.c>
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/* Generally the default presumption without further information is an
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* executable stack but this is not true for all platforms. */
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._dl_stack_flags = DEFAULT_STACK_PERMS,
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#ifdef _LIBC_REENTRANT
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._dl_load_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
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._dl_load_write_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
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._dl_load_tls_lock = _RTLD_LOCK_RECURSIVE_INITIALIZER,
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#endif
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._dl_nns = 1,
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._dl_ns =
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{
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#ifdef _LIBC_REENTRANT
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[LM_ID_BASE] = { ._ns_unique_sym_table
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= { .lock = _RTLD_LOCK_RECURSIVE_INITIALIZER } }
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#endif
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}
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};
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/* If we would use strong_alias here the compiler would see a
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non-hidden definition. This would undo the effect of the previous
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declaration. So spell out what strong_alias does plus add the
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visibility attribute. */
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extern struct rtld_global _rtld_local
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__attribute__ ((alias ("_rtld_global"), visibility ("hidden")));
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/* This variable is similar to _rtld_local, but all values are
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read-only after relocation. */
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struct rtld_global_ro _rtld_global_ro attribute_relro =
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{
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/* Get architecture specific initializer. */
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#include <dl-procinfo.c>
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#ifdef NEED_DL_SYSINFO
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._dl_sysinfo = DL_SYSINFO_DEFAULT,
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#endif
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._dl_debug_fd = STDERR_FILENO,
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._dl_lazy = 1,
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._dl_fpu_control = _FPU_DEFAULT,
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._dl_pagesize = EXEC_PAGESIZE,
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._dl_inhibit_cache = 0,
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._dl_profile_output = "/var/tmp",
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|
||
/* Function pointers. */
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._dl_debug_printf = _dl_debug_printf,
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._dl_mcount = _dl_mcount,
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._dl_lookup_symbol_x = _dl_lookup_symbol_x,
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._dl_open = _dl_open,
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._dl_close = _dl_close,
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||
._dl_catch_error = _dl_catch_error,
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._dl_error_free = _dl_error_free,
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._dl_tls_get_addr_soft = _dl_tls_get_addr_soft,
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._dl_libc_freeres = __rtld_libc_freeres,
|
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};
|
||
/* If we would use strong_alias here the compiler would see a
|
||
non-hidden definition. This would undo the effect of the previous
|
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declaration. So spell out was strong_alias does plus add the
|
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visibility attribute. */
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extern struct rtld_global_ro _rtld_local_ro
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__attribute__ ((alias ("_rtld_global_ro"), visibility ("hidden")));
|
||
|
||
|
||
static void dl_main (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
|
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ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv);
|
||
|
||
/* These two variables cannot be moved into .data.rel.ro. */
|
||
static struct libname_list _dl_rtld_libname;
|
||
|
||
/* Variable for statistics. */
|
||
RLTD_TIMING_DECLARE (relocate_time, static);
|
||
RLTD_TIMING_DECLARE (load_time, static, attribute_relro);
|
||
RLTD_TIMING_DECLARE (start_time, static, attribute_relro);
|
||
|
||
/* Additional definitions needed by TLS initialization. */
|
||
#ifdef TLS_INIT_HELPER
|
||
TLS_INIT_HELPER
|
||
#endif
|
||
|
||
/* Helper function for syscall implementation. */
|
||
#ifdef DL_SYSINFO_IMPLEMENTATION
|
||
DL_SYSINFO_IMPLEMENTATION
|
||
#endif
|
||
|
||
/* Before ld.so is relocated we must not access variables which need
|
||
relocations. This means variables which are exported. Variables
|
||
declared as static are fine. If we can mark a variable hidden this
|
||
is fine, too. The latter is important here. We can avoid setting
|
||
up a temporary link map for ld.so if we can mark _rtld_global as
|
||
hidden. */
|
||
#ifndef HIDDEN_VAR_NEEDS_DYNAMIC_RELOC
|
||
# define DONT_USE_BOOTSTRAP_MAP 1
|
||
#endif
|
||
|
||
#ifdef DONT_USE_BOOTSTRAP_MAP
|
||
static ElfW(Addr) _dl_start_final (void *arg);
|
||
#else
|
||
struct dl_start_final_info
|
||
{
|
||
struct link_map l;
|
||
RTLD_TIMING_VAR (start_time);
|
||
};
|
||
static ElfW(Addr) _dl_start_final (void *arg,
|
||
struct dl_start_final_info *info);
|
||
#endif
|
||
|
||
/* These are defined magically by the linker. */
|
||
extern const ElfW(Ehdr) __ehdr_start attribute_hidden;
|
||
extern char _etext[] attribute_hidden;
|
||
extern char _end[] attribute_hidden;
|
||
|
||
|
||
#ifdef RTLD_START
|
||
RTLD_START
|
||
#else
|
||
# error "sysdeps/MACHINE/dl-machine.h fails to define RTLD_START"
|
||
#endif
|
||
|
||
/* This is the second half of _dl_start (below). It can be inlined safely
|
||
under DONT_USE_BOOTSTRAP_MAP, where it is careful not to make any GOT
|
||
references. When the tools don't permit us to avoid using a GOT entry
|
||
for _dl_rtld_global (no attribute_hidden support), we must make sure
|
||
this function is not inlined (see below). */
|
||
|
||
#ifdef DONT_USE_BOOTSTRAP_MAP
|
||
static inline ElfW(Addr) __attribute__ ((always_inline))
|
||
_dl_start_final (void *arg)
|
||
#else
|
||
static ElfW(Addr) __attribute__ ((noinline))
|
||
_dl_start_final (void *arg, struct dl_start_final_info *info)
|
||
#endif
|
||
{
|
||
ElfW(Addr) start_addr;
|
||
|
||
__rtld_malloc_init_stubs ();
|
||
|
||
/* Do not use an initializer for these members because it would
|
||
interfere with __rtld_static_init. */
|
||
GLRO (dl_find_object) = &_dl_find_object;
|
||
|
||
/* If it hasn't happen yet record the startup time. */
|
||
rtld_timer_start (&start_time);
|
||
#if !defined DONT_USE_BOOTSTRAP_MAP
|
||
RTLD_TIMING_SET (start_time, info->start_time);
|
||
#endif
|
||
|
||
/* Transfer data about ourselves to the permanent link_map structure. */
|
||
#ifndef DONT_USE_BOOTSTRAP_MAP
|
||
GL(dl_rtld_map).l_addr = info->l.l_addr;
|
||
GL(dl_rtld_map).l_ld = info->l.l_ld;
|
||
GL(dl_rtld_map).l_ld_readonly = info->l.l_ld_readonly;
|
||
memcpy (GL(dl_rtld_map).l_info, info->l.l_info,
|
||
sizeof GL(dl_rtld_map).l_info);
|
||
GL(dl_rtld_map).l_mach = info->l.l_mach;
|
||
GL(dl_rtld_map).l_relocated = 1;
|
||
#endif
|
||
_dl_setup_hash (&GL(dl_rtld_map));
|
||
GL(dl_rtld_map).l_real = &GL(dl_rtld_map);
|
||
GL(dl_rtld_map).l_map_start = (ElfW(Addr)) &__ehdr_start;
|
||
GL(dl_rtld_map).l_map_end = (ElfW(Addr)) _end;
|
||
/* Copy the TLS related data if necessary. */
|
||
#ifndef DONT_USE_BOOTSTRAP_MAP
|
||
# if NO_TLS_OFFSET != 0
|
||
GL(dl_rtld_map).l_tls_offset = NO_TLS_OFFSET;
|
||
# endif
|
||
#endif
|
||
|
||
/* Initialize the stack end variable. */
|
||
__libc_stack_end = __builtin_frame_address (0);
|
||
|
||
/* Call the OS-dependent function to set up life so we can do things like
|
||
file access. It will call `dl_main' (below) to do all the real work
|
||
of the dynamic linker, and then unwind our frame and run the user
|
||
entry point on the same stack we entered on. */
|
||
start_addr = _dl_sysdep_start (arg, &dl_main);
|
||
|
||
if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_STATISTICS))
|
||
{
|
||
RTLD_TIMING_VAR (rtld_total_time);
|
||
rtld_timer_stop (&rtld_total_time, start_time);
|
||
print_statistics (RTLD_TIMING_REF(rtld_total_time));
|
||
}
|
||
|
||
#ifndef ELF_MACHINE_START_ADDRESS
|
||
# define ELF_MACHINE_START_ADDRESS(map, start) (start)
|
||
#endif
|
||
return ELF_MACHINE_START_ADDRESS (GL(dl_ns)[LM_ID_BASE]._ns_loaded, start_addr);
|
||
}
|
||
|
||
#ifdef DONT_USE_BOOTSTRAP_MAP
|
||
# define bootstrap_map GL(dl_rtld_map)
|
||
#else
|
||
# define bootstrap_map info.l
|
||
#endif
|
||
|
||
static ElfW(Addr) __attribute_used__
|
||
_dl_start (void *arg)
|
||
{
|
||
#ifdef DONT_USE_BOOTSTRAP_MAP
|
||
rtld_timer_start (&start_time);
|
||
#else
|
||
struct dl_start_final_info info;
|
||
rtld_timer_start (&info.start_time);
|
||
#endif
|
||
|
||
/* Partly clean the `bootstrap_map' structure up. Don't use
|
||
`memset' since it might not be built in or inlined and we cannot
|
||
make function calls at this point. Use '__builtin_memset' if we
|
||
know it is available. We do not have to clear the memory if we
|
||
do not have to use the temporary bootstrap_map. Global variables
|
||
are initialized to zero by default. */
|
||
#ifndef DONT_USE_BOOTSTRAP_MAP
|
||
# ifdef HAVE_BUILTIN_MEMSET
|
||
__builtin_memset (bootstrap_map.l_info, '\0', sizeof (bootstrap_map.l_info));
|
||
# else
|
||
for (size_t cnt = 0;
|
||
cnt < sizeof (bootstrap_map.l_info) / sizeof (bootstrap_map.l_info[0]);
|
||
++cnt)
|
||
bootstrap_map.l_info[cnt] = 0;
|
||
# endif
|
||
#endif
|
||
|
||
/* Figure out the run-time load address of the dynamic linker itself. */
|
||
bootstrap_map.l_addr = elf_machine_load_address ();
|
||
|
||
/* Read our own dynamic section and fill in the info array. */
|
||
bootstrap_map.l_ld = (void *) bootstrap_map.l_addr + elf_machine_dynamic ();
|
||
bootstrap_map.l_ld_readonly = DL_RO_DYN_SECTION;
|
||
elf_get_dynamic_info (&bootstrap_map, true, false);
|
||
|
||
#if NO_TLS_OFFSET != 0
|
||
bootstrap_map.l_tls_offset = NO_TLS_OFFSET;
|
||
#endif
|
||
|
||
#ifdef ELF_MACHINE_BEFORE_RTLD_RELOC
|
||
ELF_MACHINE_BEFORE_RTLD_RELOC (&bootstrap_map, bootstrap_map.l_info);
|
||
#endif
|
||
|
||
if (bootstrap_map.l_addr)
|
||
{
|
||
/* Relocate ourselves so we can do normal function calls and
|
||
data access using the global offset table. */
|
||
|
||
ELF_DYNAMIC_RELOCATE (&bootstrap_map, NULL, 0, 0, 0);
|
||
}
|
||
bootstrap_map.l_relocated = 1;
|
||
|
||
/* Please note that we don't allow profiling of this object and
|
||
therefore need not test whether we have to allocate the array
|
||
for the relocation results (as done in dl-reloc.c). */
|
||
|
||
/* Now life is sane; we can call functions and access global data.
|
||
Set up to use the operating system facilities, and find out from
|
||
the operating system's program loader where to find the program
|
||
header table in core. Put the rest of _dl_start into a separate
|
||
function, that way the compiler cannot put accesses to the GOT
|
||
before ELF_DYNAMIC_RELOCATE. */
|
||
|
||
#ifdef DONT_USE_BOOTSTRAP_MAP
|
||
return _dl_start_final (arg);
|
||
#else
|
||
return _dl_start_final (arg, &info);
|
||
#endif
|
||
}
|
||
|
||
|
||
|
||
/* Now life is peachy; we can do all normal operations.
|
||
On to the real work. */
|
||
|
||
/* Some helper functions. */
|
||
|
||
/* Arguments to relocate_doit. */
|
||
struct relocate_args
|
||
{
|
||
struct link_map *l;
|
||
int reloc_mode;
|
||
};
|
||
|
||
struct map_args
|
||
{
|
||
/* Argument to map_doit. */
|
||
const char *str;
|
||
struct link_map *loader;
|
||
int mode;
|
||
/* Return value of map_doit. */
|
||
struct link_map *map;
|
||
};
|
||
|
||
struct dlmopen_args
|
||
{
|
||
const char *fname;
|
||
struct link_map *map;
|
||
};
|
||
|
||
struct lookup_args
|
||
{
|
||
const char *name;
|
||
struct link_map *map;
|
||
void *result;
|
||
};
|
||
|
||
/* Arguments to version_check_doit. */
|
||
struct version_check_args
|
||
{
|
||
int doexit;
|
||
int dotrace;
|
||
};
|
||
|
||
static void
|
||
relocate_doit (void *a)
|
||
{
|
||
struct relocate_args *args = (struct relocate_args *) a;
|
||
|
||
_dl_relocate_object (args->l, args->l->l_scope, args->reloc_mode, 0);
|
||
}
|
||
|
||
static void
|
||
map_doit (void *a)
|
||
{
|
||
struct map_args *args = (struct map_args *) a;
|
||
int type = (args->mode == __RTLD_OPENEXEC) ? lt_executable : lt_library;
|
||
args->map = _dl_map_object (args->loader, args->str, type, 0,
|
||
args->mode, LM_ID_BASE);
|
||
}
|
||
|
||
static void
|
||
dlmopen_doit (void *a)
|
||
{
|
||
struct dlmopen_args *args = (struct dlmopen_args *) a;
|
||
args->map = _dl_open (args->fname,
|
||
(RTLD_LAZY | __RTLD_DLOPEN | __RTLD_AUDIT
|
||
| __RTLD_SECURE),
|
||
dl_main, LM_ID_NEWLM, _dl_argc, _dl_argv,
|
||
__environ);
|
||
}
|
||
|
||
static void
|
||
lookup_doit (void *a)
|
||
{
|
||
struct lookup_args *args = (struct lookup_args *) a;
|
||
const ElfW(Sym) *ref = NULL;
|
||
args->result = NULL;
|
||
lookup_t l = _dl_lookup_symbol_x (args->name, args->map, &ref,
|
||
args->map->l_local_scope, NULL, 0,
|
||
DL_LOOKUP_RETURN_NEWEST, NULL);
|
||
if (ref != NULL)
|
||
args->result = DL_SYMBOL_ADDRESS (l, ref);
|
||
}
|
||
|
||
static void
|
||
version_check_doit (void *a)
|
||
{
|
||
struct version_check_args *args = (struct version_check_args *) a;
|
||
if (_dl_check_all_versions (GL(dl_ns)[LM_ID_BASE]._ns_loaded, 1,
|
||
args->dotrace) && args->doexit)
|
||
/* We cannot start the application. Abort now. */
|
||
_exit (1);
|
||
}
|
||
|
||
|
||
static inline struct link_map *
|
||
find_needed (const char *name)
|
||
{
|
||
struct r_scope_elem *scope = &GL(dl_ns)[LM_ID_BASE]._ns_loaded->l_searchlist;
|
||
unsigned int n = scope->r_nlist;
|
||
|
||
while (n-- > 0)
|
||
if (_dl_name_match_p (name, scope->r_list[n]))
|
||
return scope->r_list[n];
|
||
|
||
/* Should never happen. */
|
||
return NULL;
|
||
}
|
||
|
||
static int
|
||
match_version (const char *string, struct link_map *map)
|
||
{
|
||
const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
|
||
ElfW(Verdef) *def;
|
||
|
||
#define VERDEFTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERDEF))
|
||
if (map->l_info[VERDEFTAG] == NULL)
|
||
/* The file has no symbol versioning. */
|
||
return 0;
|
||
|
||
def = (ElfW(Verdef) *) ((char *) map->l_addr
|
||
+ map->l_info[VERDEFTAG]->d_un.d_ptr);
|
||
while (1)
|
||
{
|
||
ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux);
|
||
|
||
/* Compare the version strings. */
|
||
if (strcmp (string, strtab + aux->vda_name) == 0)
|
||
/* Bingo! */
|
||
return 1;
|
||
|
||
/* If no more definitions we failed to find what we want. */
|
||
if (def->vd_next == 0)
|
||
break;
|
||
|
||
/* Next definition. */
|
||
def = (ElfW(Verdef) *) ((char *) def + def->vd_next);
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
bool __rtld_tls_init_tp_called;
|
||
|
||
static void *
|
||
init_tls (size_t naudit)
|
||
{
|
||
/* Number of elements in the static TLS block. */
|
||
GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx);
|
||
|
||
/* Do not do this twice. The audit interface might have required
|
||
the DTV interfaces to be set up early. */
|
||
if (GL(dl_initial_dtv) != NULL)
|
||
return NULL;
|
||
|
||
/* Allocate the array which contains the information about the
|
||
dtv slots. We allocate a few entries more than needed to
|
||
avoid the need for reallocation. */
|
||
size_t nelem = GL(dl_tls_max_dtv_idx) + 1 + TLS_SLOTINFO_SURPLUS;
|
||
|
||
/* Allocate. */
|
||
GL(dl_tls_dtv_slotinfo_list) = (struct dtv_slotinfo_list *)
|
||
calloc (sizeof (struct dtv_slotinfo_list)
|
||
+ nelem * sizeof (struct dtv_slotinfo), 1);
|
||
/* No need to check the return value. If memory allocation failed
|
||
the program would have been terminated. */
|
||
|
||
struct dtv_slotinfo *slotinfo = GL(dl_tls_dtv_slotinfo_list)->slotinfo;
|
||
GL(dl_tls_dtv_slotinfo_list)->len = nelem;
|
||
GL(dl_tls_dtv_slotinfo_list)->next = NULL;
|
||
|
||
/* Fill in the information from the loaded modules. No namespace
|
||
but the base one can be filled at this time. */
|
||
assert (GL(dl_ns)[LM_ID_BASE + 1]._ns_loaded == NULL);
|
||
int i = 0;
|
||
for (struct link_map *l = GL(dl_ns)[LM_ID_BASE]._ns_loaded; l != NULL;
|
||
l = l->l_next)
|
||
if (l->l_tls_blocksize != 0)
|
||
{
|
||
/* This is a module with TLS data. Store the map reference.
|
||
The generation counter is zero. */
|
||
slotinfo[i].map = l;
|
||
/* slotinfo[i].gen = 0; */
|
||
++i;
|
||
}
|
||
assert (i == GL(dl_tls_max_dtv_idx));
|
||
|
||
/* Calculate the size of the static TLS surplus. */
|
||
_dl_tls_static_surplus_init (naudit);
|
||
|
||
/* Compute the TLS offsets for the various blocks. */
|
||
_dl_determine_tlsoffset ();
|
||
|
||
/* Construct the static TLS block and the dtv for the initial
|
||
thread. For some platforms this will include allocating memory
|
||
for the thread descriptor. The memory for the TLS block will
|
||
never be freed. It should be allocated accordingly. The dtv
|
||
array can be changed if dynamic loading requires it. */
|
||
void *tcbp = _dl_allocate_tls_storage ();
|
||
if (tcbp == NULL)
|
||
_dl_fatal_printf ("\
|
||
cannot allocate TLS data structures for initial thread\n");
|
||
|
||
_dl_tls_initial_modid_limit_setup ();
|
||
|
||
/* Store for detection of the special case by __tls_get_addr
|
||
so it knows not to pass this dtv to the normal realloc. */
|
||
GL(dl_initial_dtv) = GET_DTV (tcbp);
|
||
|
||
/* And finally install it for the main thread. */
|
||
call_tls_init_tp (tcbp);
|
||
__rtld_tls_init_tp_called = true;
|
||
|
||
return tcbp;
|
||
}
|
||
|
||
static unsigned int
|
||
do_preload (const char *fname, struct link_map *main_map, const char *where)
|
||
{
|
||
const char *objname;
|
||
const char *err_str = NULL;
|
||
struct map_args args;
|
||
bool malloced;
|
||
|
||
args.str = fname;
|
||
args.loader = main_map;
|
||
args.mode = __RTLD_SECURE;
|
||
|
||
unsigned int old_nloaded = GL(dl_ns)[LM_ID_BASE]._ns_nloaded;
|
||
|
||
(void) _dl_catch_error (&objname, &err_str, &malloced, map_doit, &args);
|
||
if (__glibc_unlikely (err_str != NULL))
|
||
{
|
||
_dl_error_printf ("\
|
||
ERROR: ld.so: object '%s' from %s cannot be preloaded (%s): ignored.\n",
|
||
fname, where, err_str);
|
||
/* No need to call free, this is still before
|
||
the libc's malloc is used. */
|
||
}
|
||
else if (GL(dl_ns)[LM_ID_BASE]._ns_nloaded != old_nloaded)
|
||
/* It is no duplicate. */
|
||
return 1;
|
||
|
||
/* Nothing loaded. */
|
||
return 0;
|
||
}
|
||
|
||
static void
|
||
security_init (void)
|
||
{
|
||
/* Set up the stack checker's canary. */
|
||
uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random);
|
||
#ifdef THREAD_SET_STACK_GUARD
|
||
THREAD_SET_STACK_GUARD (stack_chk_guard);
|
||
#else
|
||
__stack_chk_guard = stack_chk_guard;
|
||
#endif
|
||
|
||
/* Set up the pointer guard as well, if necessary. */
|
||
uintptr_t pointer_chk_guard
|
||
= _dl_setup_pointer_guard (_dl_random, stack_chk_guard);
|
||
#ifdef THREAD_SET_POINTER_GUARD
|
||
THREAD_SET_POINTER_GUARD (pointer_chk_guard);
|
||
#endif
|
||
__pointer_chk_guard_local = pointer_chk_guard;
|
||
|
||
/* We do not need the _dl_random value anymore. The less
|
||
information we leave behind, the better, so clear the
|
||
variable. */
|
||
_dl_random = NULL;
|
||
}
|
||
|
||
#include <setup-vdso.h>
|
||
|
||
/* The LD_PRELOAD environment variable gives list of libraries
|
||
separated by white space or colons that are loaded before the
|
||
executable's dependencies and prepended to the global scope list.
|
||
(If the binary is running setuid all elements containing a '/' are
|
||
ignored since it is insecure.) Return the number of preloads
|
||
performed. Ditto for --preload command argument. */
|
||
unsigned int
|
||
handle_preload_list (const char *preloadlist, struct link_map *main_map,
|
||
const char *where)
|
||
{
|
||
unsigned int npreloads = 0;
|
||
const char *p = preloadlist;
|
||
char fname[SECURE_PATH_LIMIT];
|
||
|
||
while (*p != '\0')
|
||
{
|
||
/* Split preload list at space/colon. */
|
||
size_t len = strcspn (p, " :");
|
||
if (len > 0 && len < sizeof (fname))
|
||
{
|
||
memcpy (fname, p, len);
|
||
fname[len] = '\0';
|
||
}
|
||
else
|
||
fname[0] = '\0';
|
||
|
||
/* Skip over the substring and the following delimiter. */
|
||
p += len;
|
||
if (*p != '\0')
|
||
++p;
|
||
|
||
if (dso_name_valid_for_suid (fname))
|
||
npreloads += do_preload (fname, main_map, where);
|
||
}
|
||
return npreloads;
|
||
}
|
||
|
||
/* Called if the audit DSO cannot be used: if it does not have the
|
||
appropriate interfaces, or it expects a more recent version library
|
||
version than what the dynamic linker provides. */
|
||
static void
|
||
unload_audit_module (struct link_map *map, int original_tls_idx)
|
||
{
|
||
#ifndef NDEBUG
|
||
Lmid_t ns = map->l_ns;
|
||
#endif
|
||
_dl_close (map);
|
||
|
||
/* Make sure the namespace has been cleared entirely. */
|
||
assert (GL(dl_ns)[ns]._ns_loaded == NULL);
|
||
assert (GL(dl_ns)[ns]._ns_nloaded == 0);
|
||
|
||
GL(dl_tls_max_dtv_idx) = original_tls_idx;
|
||
}
|
||
|
||
/* Called to print an error message if loading of an audit module
|
||
failed. */
|
||
static void
|
||
report_audit_module_load_error (const char *name, const char *err_str,
|
||
bool malloced)
|
||
{
|
||
_dl_error_printf ("\
|
||
ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n",
|
||
name, err_str);
|
||
if (malloced)
|
||
free ((char *) err_str);
|
||
}
|
||
|
||
/* Load one audit module. */
|
||
static void
|
||
load_audit_module (const char *name, struct audit_ifaces **last_audit)
|
||
{
|
||
int original_tls_idx = GL(dl_tls_max_dtv_idx);
|
||
|
||
struct dlmopen_args dlmargs;
|
||
dlmargs.fname = name;
|
||
dlmargs.map = NULL;
|
||
|
||
const char *objname;
|
||
const char *err_str = NULL;
|
||
bool malloced;
|
||
_dl_catch_error (&objname, &err_str, &malloced, dlmopen_doit, &dlmargs);
|
||
if (__glibc_unlikely (err_str != NULL))
|
||
{
|
||
report_audit_module_load_error (name, err_str, malloced);
|
||
return;
|
||
}
|
||
|
||
struct lookup_args largs;
|
||
largs.name = "la_version";
|
||
largs.map = dlmargs.map;
|
||
_dl_catch_error (&objname, &err_str, &malloced, lookup_doit, &largs);
|
||
if (__glibc_likely (err_str != NULL))
|
||
{
|
||
unload_audit_module (dlmargs.map, original_tls_idx);
|
||
report_audit_module_load_error (name, err_str, malloced);
|
||
return;
|
||
}
|
||
|
||
unsigned int (*laversion) (unsigned int) = largs.result;
|
||
|
||
/* A null symbol indicates that something is very wrong with the
|
||
loaded object because defined symbols are supposed to have a
|
||
valid, non-null address. */
|
||
assert (laversion != NULL);
|
||
|
||
unsigned int lav = laversion (LAV_CURRENT);
|
||
if (lav == 0)
|
||
{
|
||
/* Only print an error message if debugging because this can
|
||
happen deliberately. */
|
||
if (GLRO(dl_debug_mask) & DL_DEBUG_FILES)
|
||
_dl_debug_printf ("\
|
||
file=%s [%lu]; audit interface function la_version returned zero; ignored.\n",
|
||
dlmargs.map->l_name, dlmargs.map->l_ns);
|
||
unload_audit_module (dlmargs.map, original_tls_idx);
|
||
return;
|
||
}
|
||
|
||
if (!_dl_audit_check_version (lav))
|
||
{
|
||
_dl_debug_printf ("\
|
||
ERROR: audit interface '%s' requires version %d (maximum supported version %d); ignored.\n",
|
||
name, lav, LAV_CURRENT);
|
||
unload_audit_module (dlmargs.map, original_tls_idx);
|
||
return;
|
||
}
|
||
|
||
enum { naudit_ifaces = 8 };
|
||
union
|
||
{
|
||
struct audit_ifaces ifaces;
|
||
void (*fptr[naudit_ifaces]) (void);
|
||
} *newp = malloc (sizeof (*newp));
|
||
if (newp == NULL)
|
||
_dl_fatal_printf ("Out of memory while loading audit modules\n");
|
||
|
||
/* Names of the auditing interfaces. All in one
|
||
long string. */
|
||
static const char audit_iface_names[] =
|
||
"la_activity\0"
|
||
"la_objsearch\0"
|
||
"la_objopen\0"
|
||
"la_preinit\0"
|
||
LA_SYMBIND "\0"
|
||
#define STRING(s) __STRING (s)
|
||
"la_" STRING (ARCH_LA_PLTENTER) "\0"
|
||
"la_" STRING (ARCH_LA_PLTEXIT) "\0"
|
||
"la_objclose\0";
|
||
unsigned int cnt = 0;
|
||
const char *cp = audit_iface_names;
|
||
do
|
||
{
|
||
largs.name = cp;
|
||
_dl_catch_error (&objname, &err_str, &malloced, lookup_doit, &largs);
|
||
|
||
/* Store the pointer. */
|
||
if (err_str == NULL && largs.result != NULL)
|
||
newp->fptr[cnt] = largs.result;
|
||
else
|
||
newp->fptr[cnt] = NULL;
|
||
++cnt;
|
||
|
||
cp = strchr (cp, '\0') + 1;
|
||
}
|
||
while (*cp != '\0');
|
||
assert (cnt == naudit_ifaces);
|
||
|
||
/* Now append the new auditing interface to the list. */
|
||
newp->ifaces.next = NULL;
|
||
if (*last_audit == NULL)
|
||
*last_audit = GLRO(dl_audit) = &newp->ifaces;
|
||
else
|
||
*last_audit = (*last_audit)->next = &newp->ifaces;
|
||
|
||
/* The dynamic linker link map is statically allocated, so the
|
||
cookie in _dl_new_object has not happened. */
|
||
link_map_audit_state (&GL (dl_rtld_map), GLRO (dl_naudit))->cookie
|
||
= (intptr_t) &GL (dl_rtld_map);
|
||
|
||
++GLRO(dl_naudit);
|
||
|
||
/* Mark the DSO as being used for auditing. */
|
||
dlmargs.map->l_auditing = 1;
|
||
}
|
||
|
||
/* Load all audit modules. */
|
||
static void
|
||
load_audit_modules (struct link_map *main_map, struct audit_list *audit_list)
|
||
{
|
||
struct audit_ifaces *last_audit = NULL;
|
||
|
||
while (true)
|
||
{
|
||
const char *name = audit_list_next (audit_list);
|
||
if (name == NULL)
|
||
break;
|
||
load_audit_module (name, &last_audit);
|
||
}
|
||
|
||
/* Notify audit modules of the initially loaded modules (the main
|
||
program and the dynamic linker itself). */
|
||
if (GLRO(dl_naudit) > 0)
|
||
{
|
||
_dl_audit_objopen (main_map, LM_ID_BASE);
|
||
_dl_audit_objopen (&GL(dl_rtld_map), LM_ID_BASE);
|
||
}
|
||
}
|
||
|
||
/* Check if the executable is not actually dynamically linked, and
|
||
invoke it directly in that case. */
|
||
static void
|
||
rtld_chain_load (struct link_map *main_map, char *argv0)
|
||
{
|
||
/* The dynamic loader run against itself. */
|
||
const char *rtld_soname
|
||
= ((const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
|
||
+ GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_val);
|
||
if (main_map->l_info[DT_SONAME] != NULL
|
||
&& strcmp (rtld_soname,
|
||
((const char *) D_PTR (main_map, l_info[DT_STRTAB])
|
||
+ main_map->l_info[DT_SONAME]->d_un.d_val)) == 0)
|
||
_dl_fatal_printf ("%s: loader cannot load itself\n", rtld_soname);
|
||
|
||
/* With DT_NEEDED dependencies, the executable is dynamically
|
||
linked. */
|
||
if (__glibc_unlikely (main_map->l_info[DT_NEEDED] != NULL))
|
||
return;
|
||
|
||
/* If the executable has program interpreter, it is dynamically
|
||
linked. */
|
||
for (size_t i = 0; i < main_map->l_phnum; ++i)
|
||
if (main_map->l_phdr[i].p_type == PT_INTERP)
|
||
return;
|
||
|
||
const char *pathname = _dl_argv[0];
|
||
if (argv0 != NULL)
|
||
_dl_argv[0] = argv0;
|
||
int errcode = __rtld_execve (pathname, _dl_argv, _environ);
|
||
const char *errname = strerrorname_np (errcode);
|
||
if (errname != NULL)
|
||
_dl_fatal_printf("%s: cannot execute %s: %s\n",
|
||
rtld_soname, pathname, errname);
|
||
else
|
||
_dl_fatal_printf("%s: cannot execute %s: %d\n",
|
||
rtld_soname, pathname, errcode);
|
||
}
|
||
|
||
/* Called to complete the initialization of the link map for the main
|
||
executable. Returns true if there is a PT_INTERP segment. */
|
||
static bool
|
||
rtld_setup_main_map (struct link_map *main_map)
|
||
{
|
||
/* This have already been filled in right after _dl_new_object, or
|
||
as part of _dl_map_object. */
|
||
const ElfW(Phdr) *phdr = main_map->l_phdr;
|
||
ElfW(Word) phnum = main_map->l_phnum;
|
||
|
||
bool has_interp = false;
|
||
|
||
main_map->l_map_end = 0;
|
||
/* Perhaps the executable has no PT_LOAD header entries at all. */
|
||
main_map->l_map_start = ~0;
|
||
/* And it was opened directly. */
|
||
++main_map->l_direct_opencount;
|
||
main_map->l_contiguous = 1;
|
||
|
||
/* A PT_LOAD segment at an unexpected address will clear the
|
||
l_contiguous flag. The ELF specification says that PT_LOAD
|
||
segments need to be sorted in in increasing order, but perhaps
|
||
not all executables follow this requirement. Having l_contiguous
|
||
equal to 1 is just an optimization, so the code below does not
|
||
try to sort the segments in case they are unordered.
|
||
|
||
There is one corner case in which l_contiguous is not set to 1,
|
||
but where it could be set: If a PIE (ET_DYN) binary is loaded by
|
||
glibc itself (not the kernel), it is always contiguous due to the
|
||
way the glibc loader works. However, the kernel loader may still
|
||
create holes in this case, and the code here still uses 0
|
||
conservatively for the glibc-loaded case, too. */
|
||
ElfW(Addr) expected_load_address = 0;
|
||
|
||
/* Scan the program header table for the dynamic section. */
|
||
for (const ElfW(Phdr) *ph = phdr; ph < &phdr[phnum]; ++ph)
|
||
switch (ph->p_type)
|
||
{
|
||
case PT_PHDR:
|
||
/* Find out the load address. */
|
||
main_map->l_addr = (ElfW(Addr)) phdr - ph->p_vaddr;
|
||
break;
|
||
case PT_DYNAMIC:
|
||
/* This tells us where to find the dynamic section,
|
||
which tells us everything we need to do. */
|
||
main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr;
|
||
main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0;
|
||
break;
|
||
case PT_INTERP:
|
||
/* This "interpreter segment" was used by the program loader to
|
||
find the program interpreter, which is this program itself, the
|
||
dynamic linker. We note what name finds us, so that a future
|
||
dlopen call or DT_NEEDED entry, for something that wants to link
|
||
against the dynamic linker as a shared library, will know that
|
||
the shared object is already loaded. */
|
||
_dl_rtld_libname.name = ((const char *) main_map->l_addr
|
||
+ ph->p_vaddr);
|
||
/* _dl_rtld_libname.next = NULL; Already zero. */
|
||
GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
|
||
|
||
has_interp = true;
|
||
break;
|
||
case PT_LOAD:
|
||
{
|
||
ElfW(Addr) mapstart;
|
||
ElfW(Addr) allocend;
|
||
|
||
/* Remember where the main program starts in memory. */
|
||
mapstart = (main_map->l_addr
|
||
+ (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1)));
|
||
if (main_map->l_map_start > mapstart)
|
||
main_map->l_map_start = mapstart;
|
||
|
||
if (main_map->l_contiguous && expected_load_address != 0
|
||
&& expected_load_address != mapstart)
|
||
main_map->l_contiguous = 0;
|
||
|
||
/* Also where it ends. */
|
||
allocend = main_map->l_addr + ph->p_vaddr + ph->p_memsz;
|
||
if (main_map->l_map_end < allocend)
|
||
main_map->l_map_end = allocend;
|
||
|
||
/* The next expected address is the page following this load
|
||
segment. */
|
||
expected_load_address = ((allocend + GLRO(dl_pagesize) - 1)
|
||
& ~(GLRO(dl_pagesize) - 1));
|
||
}
|
||
break;
|
||
|
||
case PT_TLS:
|
||
if (ph->p_memsz > 0)
|
||
{
|
||
/* Note that in the case the dynamic linker we duplicate work
|
||
here since we read the PT_TLS entry already in
|
||
_dl_start_final. But the result is repeatable so do not
|
||
check for this special but unimportant case. */
|
||
main_map->l_tls_blocksize = ph->p_memsz;
|
||
main_map->l_tls_align = ph->p_align;
|
||
if (ph->p_align == 0)
|
||
main_map->l_tls_firstbyte_offset = 0;
|
||
else
|
||
main_map->l_tls_firstbyte_offset = (ph->p_vaddr
|
||
& (ph->p_align - 1));
|
||
main_map->l_tls_initimage_size = ph->p_filesz;
|
||
main_map->l_tls_initimage = (void *) ph->p_vaddr;
|
||
|
||
/* This image gets the ID one. */
|
||
GL(dl_tls_max_dtv_idx) = main_map->l_tls_modid = 1;
|
||
}
|
||
break;
|
||
|
||
case PT_GNU_STACK:
|
||
GL(dl_stack_flags) = ph->p_flags;
|
||
break;
|
||
|
||
case PT_GNU_RELRO:
|
||
main_map->l_relro_addr = ph->p_vaddr;
|
||
main_map->l_relro_size = ph->p_memsz;
|
||
break;
|
||
}
|
||
/* Process program headers again, but scan them backwards so
|
||
that PT_NOTE can be skipped if PT_GNU_PROPERTY exits. */
|
||
for (const ElfW(Phdr) *ph = &phdr[phnum]; ph != phdr; --ph)
|
||
switch (ph[-1].p_type)
|
||
{
|
||
case PT_NOTE:
|
||
_dl_process_pt_note (main_map, -1, &ph[-1]);
|
||
break;
|
||
case PT_GNU_PROPERTY:
|
||
_dl_process_pt_gnu_property (main_map, -1, &ph[-1]);
|
||
break;
|
||
}
|
||
|
||
/* Adjust the address of the TLS initialization image in case
|
||
the executable is actually an ET_DYN object. */
|
||
if (main_map->l_tls_initimage != NULL)
|
||
main_map->l_tls_initimage
|
||
= (char *) main_map->l_tls_initimage + main_map->l_addr;
|
||
if (! main_map->l_map_end)
|
||
main_map->l_map_end = ~0;
|
||
if (! GL(dl_rtld_map).l_libname && GL(dl_rtld_map).l_name)
|
||
{
|
||
/* We were invoked directly, so the program might not have a
|
||
PT_INTERP. */
|
||
_dl_rtld_libname.name = GL(dl_rtld_map).l_name;
|
||
/* _dl_rtld_libname.next = NULL; Already zero. */
|
||
GL(dl_rtld_map).l_libname = &_dl_rtld_libname;
|
||
}
|
||
else
|
||
assert (GL(dl_rtld_map).l_libname); /* How else did we get here? */
|
||
|
||
return has_interp;
|
||
}
|
||
|
||
/* Adjusts the contents of the stack and related globals for the user
|
||
entry point. The ld.so processed skip_args arguments and bumped
|
||
_dl_argv and _dl_argc accordingly. Those arguments are removed from
|
||
argv here. */
|
||
static void
|
||
_dl_start_args_adjust (int skip_args, int skip_env)
|
||
{
|
||
void **sp = (void **) (_dl_argv - skip_args - 1);
|
||
void **p = sp + skip_args;
|
||
|
||
if (skip_args == 0)
|
||
return;
|
||
|
||
/* Sanity check. */
|
||
intptr_t argc __attribute__ ((unused)) = (intptr_t) sp[0] - skip_args;
|
||
assert (argc == _dl_argc);
|
||
|
||
/* Adjust argc on stack. */
|
||
sp[0] = (void *) (intptr_t) _dl_argc;
|
||
|
||
/* Update globals in rtld. */
|
||
_dl_argv -= skip_args;
|
||
_environ -= skip_args;
|
||
|
||
/* Shuffle argv down. */
|
||
do
|
||
*++sp = *++p;
|
||
while (*p != NULL);
|
||
|
||
assert (_environ == (char **) (sp + 1));
|
||
|
||
/* Shuffle envp down. */
|
||
do
|
||
*++sp = *++p;
|
||
while (*p != NULL);
|
||
|
||
#ifdef HAVE_AUX_VECTOR
|
||
void **auxv = (void **) GLRO(dl_auxv) - skip_args - skip_env;
|
||
GLRO(dl_auxv) = (ElfW(auxv_t) *) auxv; /* Aliasing violation. */
|
||
assert (auxv == sp + 1);
|
||
|
||
/* Shuffle auxv down. */
|
||
ElfW(auxv_t) ax;
|
||
char *oldp = (char *) (p + 1 + skip_env);
|
||
char *newp = (char *) (sp + 1);
|
||
do
|
||
{
|
||
memcpy (&ax, oldp, sizeof (ax));
|
||
memcpy (newp, &ax, sizeof (ax));
|
||
oldp += sizeof (ax);
|
||
newp += sizeof (ax);
|
||
}
|
||
while (ax.a_type != AT_NULL);
|
||
#endif
|
||
}
|
||
|
||
static void
|
||
dl_main (const ElfW(Phdr) *phdr,
|
||
ElfW(Word) phnum,
|
||
ElfW(Addr) *user_entry,
|
||
ElfW(auxv_t) *auxv)
|
||
{
|
||
struct link_map *main_map;
|
||
size_t file_size;
|
||
char *file;
|
||
unsigned int i;
|
||
bool rtld_is_main = false;
|
||
void *tcbp = NULL;
|
||
int skip_env = 0;
|
||
|
||
struct dl_main_state state;
|
||
dl_main_state_init (&state);
|
||
|
||
__tls_pre_init_tp ();
|
||
|
||
#if !PTHREAD_IN_LIBC
|
||
/* The explicit initialization here is cheaper than processing the reloc
|
||
in the _rtld_local definition's initializer. */
|
||
GL(dl_make_stack_executable_hook) = &_dl_make_stack_executable;
|
||
#endif
|
||
|
||
/* Process the environment variable which control the behaviour. */
|
||
skip_env = process_envvars (&state);
|
||
|
||
#ifndef HAVE_INLINED_SYSCALLS
|
||
/* Set up a flag which tells we are just starting. */
|
||
_dl_starting_up = 1;
|
||
#endif
|
||
|
||
const char *ld_so_name = _dl_argv[0];
|
||
if (*user_entry == (ElfW(Addr)) ENTRY_POINT)
|
||
{
|
||
/* Ho ho. We are not the program interpreter! We are the program
|
||
itself! This means someone ran ld.so as a command. Well, that
|
||
might be convenient to do sometimes. We support it by
|
||
interpreting the args like this:
|
||
|
||
ld.so PROGRAM ARGS...
|
||
|
||
The first argument is the name of a file containing an ELF
|
||
executable we will load and run with the following arguments.
|
||
To simplify life here, PROGRAM is searched for using the
|
||
normal rules for shared objects, rather than $PATH or anything
|
||
like that. We just load it and use its entry point; we don't
|
||
pay attention to its PT_INTERP command (we are the interpreter
|
||
ourselves). This is an easy way to test a new ld.so before
|
||
installing it. */
|
||
rtld_is_main = true;
|
||
|
||
char *argv0 = NULL;
|
||
char **orig_argv = _dl_argv;
|
||
|
||
/* Note the place where the dynamic linker actually came from. */
|
||
GL(dl_rtld_map).l_name = rtld_progname;
|
||
|
||
while (_dl_argc > 1)
|
||
if (! strcmp (_dl_argv[1], "--list"))
|
||
{
|
||
if (state.mode != rtld_mode_help)
|
||
{
|
||
state.mode = rtld_mode_list;
|
||
/* This means do no dependency analysis. */
|
||
GLRO(dl_lazy) = -1;
|
||
}
|
||
|
||
--_dl_argc;
|
||
++_dl_argv;
|
||
}
|
||
else if (! strcmp (_dl_argv[1], "--verify"))
|
||
{
|
||
if (state.mode != rtld_mode_help)
|
||
state.mode = rtld_mode_verify;
|
||
|
||
--_dl_argc;
|
||
++_dl_argv;
|
||
}
|
||
else if (! strcmp (_dl_argv[1], "--inhibit-cache"))
|
||
{
|
||
GLRO(dl_inhibit_cache) = 1;
|
||
--_dl_argc;
|
||
++_dl_argv;
|
||
}
|
||
else if (! strcmp (_dl_argv[1], "--library-path")
|
||
&& _dl_argc > 2)
|
||
{
|
||
state.library_path = _dl_argv[2];
|
||
state.library_path_source = "--library-path";
|
||
|
||
_dl_argc -= 2;
|
||
_dl_argv += 2;
|
||
}
|
||
else if (! strcmp (_dl_argv[1], "--inhibit-rpath")
|
||
&& _dl_argc > 2)
|
||
{
|
||
GLRO(dl_inhibit_rpath) = _dl_argv[2];
|
||
|
||
_dl_argc -= 2;
|
||
_dl_argv += 2;
|
||
}
|
||
else if (! strcmp (_dl_argv[1], "--audit") && _dl_argc > 2)
|
||
{
|
||
audit_list_add_string (&state.audit_list, _dl_argv[2]);
|
||
|
||
_dl_argc -= 2;
|
||
_dl_argv += 2;
|
||
}
|
||
else if (! strcmp (_dl_argv[1], "--preload") && _dl_argc > 2)
|
||
{
|
||
state.preloadarg = _dl_argv[2];
|
||
_dl_argc -= 2;
|
||
_dl_argv += 2;
|
||
}
|
||
else if (! strcmp (_dl_argv[1], "--argv0") && _dl_argc > 2)
|
||
{
|
||
argv0 = _dl_argv[2];
|
||
|
||
_dl_argc -= 2;
|
||
_dl_argv += 2;
|
||
}
|
||
else if (strcmp (_dl_argv[1], "--glibc-hwcaps-prepend") == 0
|
||
&& _dl_argc > 2)
|
||
{
|
||
state.glibc_hwcaps_prepend = _dl_argv[2];
|
||
_dl_argc -= 2;
|
||
_dl_argv += 2;
|
||
}
|
||
else if (strcmp (_dl_argv[1], "--glibc-hwcaps-mask") == 0
|
||
&& _dl_argc > 2)
|
||
{
|
||
state.glibc_hwcaps_mask = _dl_argv[2];
|
||
_dl_argc -= 2;
|
||
_dl_argv += 2;
|
||
}
|
||
else if (! strcmp (_dl_argv[1], "--list-tunables"))
|
||
{
|
||
state.mode = rtld_mode_list_tunables;
|
||
|
||
--_dl_argc;
|
||
++_dl_argv;
|
||
}
|
||
else if (! strcmp (_dl_argv[1], "--list-diagnostics"))
|
||
{
|
||
state.mode = rtld_mode_list_diagnostics;
|
||
|
||
--_dl_argc;
|
||
++_dl_argv;
|
||
}
|
||
else if (strcmp (_dl_argv[1], "--help") == 0)
|
||
{
|
||
state.mode = rtld_mode_help;
|
||
--_dl_argc;
|
||
++_dl_argv;
|
||
}
|
||
else if (strcmp (_dl_argv[1], "--version") == 0)
|
||
_dl_version ();
|
||
else if (_dl_argv[1][0] == '-' && _dl_argv[1][1] == '-')
|
||
{
|
||
if (_dl_argv[1][2] == '\0')
|
||
{
|
||
/* End of option list. */
|
||
--_dl_argc;
|
||
++_dl_argv;
|
||
break;
|
||
}
|
||
else
|
||
/* Unrecognized option. */
|
||
_dl_usage (ld_so_name, _dl_argv[1]);
|
||
}
|
||
else
|
||
break;
|
||
|
||
if (__glibc_unlikely (state.mode == rtld_mode_list_tunables))
|
||
{
|
||
__tunables_print ();
|
||
_exit (0);
|
||
}
|
||
|
||
if (state.mode == rtld_mode_list_diagnostics)
|
||
_dl_print_diagnostics (_environ);
|
||
|
||
/* If we have no further argument the program was called incorrectly.
|
||
Grant the user some education. */
|
||
if (_dl_argc < 2)
|
||
{
|
||
if (state.mode == rtld_mode_help)
|
||
/* --help without an executable is not an error. */
|
||
_dl_help (ld_so_name, &state);
|
||
else
|
||
_dl_usage (ld_so_name, NULL);
|
||
}
|
||
|
||
--_dl_argc;
|
||
++_dl_argv;
|
||
|
||
/* The initialization of _dl_stack_flags done below assumes the
|
||
executable's PT_GNU_STACK may have been honored by the kernel, and
|
||
so a PT_GNU_STACK with PF_X set means the stack started out with
|
||
execute permission. However, this is not really true if the
|
||
dynamic linker is the executable the kernel loaded. For this
|
||
case, we must reinitialize _dl_stack_flags to match the dynamic
|
||
linker itself. If the dynamic linker was built with a
|
||
PT_GNU_STACK, then the kernel may have loaded us with a
|
||
nonexecutable stack that we will have to make executable when we
|
||
load the program below unless it has a PT_GNU_STACK indicating
|
||
nonexecutable stack is ok. */
|
||
|
||
for (const ElfW(Phdr) *ph = phdr; ph < &phdr[phnum]; ++ph)
|
||
if (ph->p_type == PT_GNU_STACK)
|
||
{
|
||
GL(dl_stack_flags) = ph->p_flags;
|
||
break;
|
||
}
|
||
|
||
if (__glibc_unlikely (state.mode == rtld_mode_verify
|
||
|| state.mode == rtld_mode_help))
|
||
{
|
||
const char *objname;
|
||
const char *err_str = NULL;
|
||
struct map_args args;
|
||
bool malloced;
|
||
|
||
args.str = rtld_progname;
|
||
args.loader = NULL;
|
||
args.mode = __RTLD_OPENEXEC;
|
||
(void) _dl_catch_error (&objname, &err_str, &malloced, map_doit,
|
||
&args);
|
||
if (__glibc_unlikely (err_str != NULL))
|
||
{
|
||
/* We don't free the returned string, the programs stops
|
||
anyway. */
|
||
if (state.mode == rtld_mode_help)
|
||
/* Mask the failure to load the main object. The help
|
||
message contains less information in this case. */
|
||
_dl_help (ld_so_name, &state);
|
||
else
|
||
_exit (EXIT_FAILURE);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
RTLD_TIMING_VAR (start);
|
||
rtld_timer_start (&start);
|
||
_dl_map_object (NULL, rtld_progname, lt_executable, 0,
|
||
__RTLD_OPENEXEC, LM_ID_BASE);
|
||
rtld_timer_stop (&load_time, start);
|
||
}
|
||
|
||
/* Now the map for the main executable is available. */
|
||
main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
|
||
|
||
if (__glibc_likely (state.mode == rtld_mode_normal))
|
||
rtld_chain_load (main_map, argv0);
|
||
|
||
phdr = main_map->l_phdr;
|
||
phnum = main_map->l_phnum;
|
||
/* We overwrite here a pointer to a malloc()ed string. But since
|
||
the malloc() implementation used at this point is the dummy
|
||
implementations which has no real free() function it does not
|
||
makes sense to free the old string first. */
|
||
main_map->l_name = (char *) "";
|
||
*user_entry = main_map->l_entry;
|
||
|
||
/* Set bit indicating this is the main program map. */
|
||
main_map->l_main_map = 1;
|
||
|
||
#ifdef HAVE_AUX_VECTOR
|
||
/* Adjust the on-stack auxiliary vector so that it looks like the
|
||
binary was executed directly. */
|
||
for (ElfW(auxv_t) *av = auxv; av->a_type != AT_NULL; av++)
|
||
switch (av->a_type)
|
||
{
|
||
case AT_PHDR:
|
||
av->a_un.a_val = (uintptr_t) phdr;
|
||
break;
|
||
case AT_PHNUM:
|
||
av->a_un.a_val = phnum;
|
||
break;
|
||
case AT_ENTRY:
|
||
av->a_un.a_val = *user_entry;
|
||
break;
|
||
case AT_EXECFN:
|
||
av->a_un.a_val = (uintptr_t) _dl_argv[0];
|
||
break;
|
||
}
|
||
#endif
|
||
|
||
/* Set the argv[0] string now that we've processed the executable. */
|
||
if (argv0 != NULL)
|
||
_dl_argv[0] = argv0;
|
||
|
||
/* Adjust arguments for the application entry point. */
|
||
_dl_start_args_adjust (_dl_argv - orig_argv, skip_env);
|
||
}
|
||
else
|
||
{
|
||
/* Create a link_map for the executable itself.
|
||
This will be what dlopen on "" returns. */
|
||
main_map = _dl_new_object ((char *) "", "", lt_executable, NULL,
|
||
__RTLD_OPENEXEC, LM_ID_BASE);
|
||
assert (main_map != NULL);
|
||
main_map->l_phdr = phdr;
|
||
main_map->l_phnum = phnum;
|
||
main_map->l_entry = *user_entry;
|
||
|
||
/* Even though the link map is not yet fully initialized we can add
|
||
it to the map list since there are no possible users running yet. */
|
||
_dl_add_to_namespace_list (main_map, LM_ID_BASE);
|
||
assert (main_map == GL(dl_ns)[LM_ID_BASE]._ns_loaded);
|
||
|
||
/* At this point we are in a bit of trouble. We would have to
|
||
fill in the values for l_dev and l_ino. But in general we
|
||
do not know where the file is. We also do not handle AT_EXECFD
|
||
even if it would be passed up.
|
||
|
||
We leave the values here defined to 0. This is normally no
|
||
problem as the program code itself is normally no shared
|
||
object and therefore cannot be loaded dynamically. Nothing
|
||
prevent the use of dynamic binaries and in these situations
|
||
we might get problems. We might not be able to find out
|
||
whether the object is already loaded. But since there is no
|
||
easy way out and because the dynamic binary must also not
|
||
have an SONAME we ignore this program for now. If it becomes
|
||
a problem we can force people using SONAMEs. */
|
||
|
||
/* We delay initializing the path structure until we got the dynamic
|
||
information for the program. */
|
||
}
|
||
|
||
bool has_interp = rtld_setup_main_map (main_map);
|
||
|
||
/* If the current libname is different from the SONAME, add the
|
||
latter as well. */
|
||
if (GL(dl_rtld_map).l_info[DT_SONAME] != NULL
|
||
&& strcmp (GL(dl_rtld_map).l_libname->name,
|
||
(const char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
|
||
+ GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_val) != 0)
|
||
{
|
||
static struct libname_list newname;
|
||
newname.name = ((char *) D_PTR (&GL(dl_rtld_map), l_info[DT_STRTAB])
|
||
+ GL(dl_rtld_map).l_info[DT_SONAME]->d_un.d_ptr);
|
||
newname.next = NULL;
|
||
newname.dont_free = 1;
|
||
|
||
assert (GL(dl_rtld_map).l_libname->next == NULL);
|
||
GL(dl_rtld_map).l_libname->next = &newname;
|
||
}
|
||
/* The ld.so must be relocated since otherwise loading audit modules
|
||
will fail since they reuse the very same ld.so. */
|
||
assert (GL(dl_rtld_map).l_relocated);
|
||
|
||
if (! rtld_is_main)
|
||
{
|
||
/* Extract the contents of the dynamic section for easy access. */
|
||
elf_get_dynamic_info (main_map, false, false);
|
||
|
||
/* If the main map is libc.so, update the base namespace to
|
||
refer to this map. If libc.so is loaded later, this happens
|
||
in _dl_map_object_from_fd. */
|
||
if (main_map->l_info[DT_SONAME] != NULL
|
||
&& (strcmp (((const char *) D_PTR (main_map, l_info[DT_STRTAB])
|
||
+ main_map->l_info[DT_SONAME]->d_un.d_val), LIBC_SO)
|
||
== 0))
|
||
GL(dl_ns)[LM_ID_BASE].libc_map = main_map;
|
||
|
||
/* Set up our cache of pointers into the hash table. */
|
||
_dl_setup_hash (main_map);
|
||
}
|
||
|
||
if (__glibc_unlikely (state.mode == rtld_mode_verify))
|
||
{
|
||
/* We were called just to verify that this is a dynamic
|
||
executable using us as the program interpreter. Exit with an
|
||
error if we were not able to load the binary or no interpreter
|
||
is specified (i.e., this is no dynamically linked binary. */
|
||
if (main_map->l_ld == NULL)
|
||
_exit (1);
|
||
|
||
_exit (has_interp ? 0 : 2);
|
||
}
|
||
|
||
struct link_map **first_preload = &GL(dl_rtld_map).l_next;
|
||
/* Set up the data structures for the system-supplied DSO early,
|
||
so they can influence _dl_init_paths. */
|
||
setup_vdso (main_map, &first_preload);
|
||
|
||
/* With vDSO setup we can initialize the function pointers. */
|
||
setup_vdso_pointers ();
|
||
|
||
/* Initialize the data structures for the search paths for shared
|
||
objects. */
|
||
call_init_paths (&state);
|
||
|
||
/* Initialize _r_debug_extended. */
|
||
struct r_debug *r = _dl_debug_initialize (GL(dl_rtld_map).l_addr,
|
||
LM_ID_BASE);
|
||
r->r_state = RT_CONSISTENT;
|
||
|
||
/* Put the link_map for ourselves on the chain so it can be found by
|
||
name. Note that at this point the global chain of link maps contains
|
||
exactly one element, which is pointed to by dl_loaded. */
|
||
if (! GL(dl_rtld_map).l_name)
|
||
/* If not invoked directly, the dynamic linker shared object file was
|
||
found by the PT_INTERP name. */
|
||
GL(dl_rtld_map).l_name = (char *) GL(dl_rtld_map).l_libname->name;
|
||
GL(dl_rtld_map).l_type = lt_library;
|
||
main_map->l_next = &GL(dl_rtld_map);
|
||
GL(dl_rtld_map).l_prev = main_map;
|
||
++GL(dl_ns)[LM_ID_BASE]._ns_nloaded;
|
||
++GL(dl_load_adds);
|
||
|
||
/* Starting from binutils-2.23, the linker will define the magic symbol
|
||
__ehdr_start to point to our own ELF header if it is visible in a
|
||
segment that also includes the phdrs. If that's not available, we use
|
||
the old method that assumes the beginning of the file is part of the
|
||
lowest-addressed PT_LOAD segment. */
|
||
|
||
/* Set up the program header information for the dynamic linker
|
||
itself. It is needed in the dl_iterate_phdr callbacks. */
|
||
const ElfW(Ehdr) *rtld_ehdr = &__ehdr_start;
|
||
assert (rtld_ehdr->e_ehsize == sizeof *rtld_ehdr);
|
||
assert (rtld_ehdr->e_phentsize == sizeof (ElfW(Phdr)));
|
||
|
||
const ElfW(Phdr) *rtld_phdr = (const void *) rtld_ehdr + rtld_ehdr->e_phoff;
|
||
|
||
GL(dl_rtld_map).l_phdr = rtld_phdr;
|
||
GL(dl_rtld_map).l_phnum = rtld_ehdr->e_phnum;
|
||
|
||
|
||
/* PT_GNU_RELRO is usually the last phdr. */
|
||
size_t cnt = rtld_ehdr->e_phnum;
|
||
while (cnt-- > 0)
|
||
if (rtld_phdr[cnt].p_type == PT_GNU_RELRO)
|
||
{
|
||
GL(dl_rtld_map).l_relro_addr = rtld_phdr[cnt].p_vaddr;
|
||
GL(dl_rtld_map).l_relro_size = rtld_phdr[cnt].p_memsz;
|
||
break;
|
||
}
|
||
|
||
/* Add the dynamic linker to the TLS list if it also uses TLS. */
|
||
if (GL(dl_rtld_map).l_tls_blocksize != 0)
|
||
/* Assign a module ID. Do this before loading any audit modules. */
|
||
_dl_assign_tls_modid (&GL(dl_rtld_map));
|
||
|
||
audit_list_add_dynamic_tag (&state.audit_list, main_map, DT_AUDIT);
|
||
audit_list_add_dynamic_tag (&state.audit_list, main_map, DT_DEPAUDIT);
|
||
|
||
/* At this point, all data has been obtained that is included in the
|
||
--help output. */
|
||
if (__glibc_unlikely (state.mode == rtld_mode_help))
|
||
_dl_help (ld_so_name, &state);
|
||
|
||
/* If we have auditing DSOs to load, do it now. */
|
||
bool need_security_init = true;
|
||
if (state.audit_list.length > 0)
|
||
{
|
||
size_t naudit = audit_list_count (&state.audit_list);
|
||
|
||
/* Since we start using the auditing DSOs right away we need to
|
||
initialize the data structures now. */
|
||
tcbp = init_tls (naudit);
|
||
|
||
/* Initialize security features. We need to do it this early
|
||
since otherwise the constructors of the audit libraries will
|
||
use different values (especially the pointer guard) and will
|
||
fail later on. */
|
||
security_init ();
|
||
need_security_init = false;
|
||
|
||
load_audit_modules (main_map, &state.audit_list);
|
||
|
||
/* The count based on audit strings may overestimate the number
|
||
of audit modules that got loaded, but not underestimate. */
|
||
assert (GLRO(dl_naudit) <= naudit);
|
||
}
|
||
|
||
/* Keep track of the currently loaded modules to count how many
|
||
non-audit modules which use TLS are loaded. */
|
||
size_t count_modids = _dl_count_modids ();
|
||
|
||
/* Set up debugging before the debugger is notified for the first time. */
|
||
elf_setup_debug_entry (main_map, r);
|
||
|
||
/* We start adding objects. */
|
||
r->r_state = RT_ADD;
|
||
_dl_debug_state ();
|
||
LIBC_PROBE (init_start, 2, LM_ID_BASE, r);
|
||
|
||
/* Auditing checkpoint: we are ready to signal that the initial map
|
||
is being constructed. */
|
||
_dl_audit_activity_map (main_map, LA_ACT_ADD);
|
||
|
||
/* We have two ways to specify objects to preload: via environment
|
||
variable and via the file /etc/ld.so.preload. The latter can also
|
||
be used when security is enabled. */
|
||
assert (*first_preload == NULL);
|
||
struct link_map **preloads = NULL;
|
||
unsigned int npreloads = 0;
|
||
|
||
if (__glibc_unlikely (state.preloadlist != NULL))
|
||
{
|
||
RTLD_TIMING_VAR (start);
|
||
rtld_timer_start (&start);
|
||
npreloads += handle_preload_list (state.preloadlist, main_map,
|
||
"LD_PRELOAD");
|
||
rtld_timer_accum (&load_time, start);
|
||
}
|
||
|
||
if (__glibc_unlikely (state.preloadarg != NULL))
|
||
{
|
||
RTLD_TIMING_VAR (start);
|
||
rtld_timer_start (&start);
|
||
npreloads += handle_preload_list (state.preloadarg, main_map,
|
||
"--preload");
|
||
rtld_timer_accum (&load_time, start);
|
||
}
|
||
|
||
/* There usually is no ld.so.preload file, it should only be used
|
||
for emergencies and testing. So the open call etc should usually
|
||
fail. Using access() on a non-existing file is faster than using
|
||
open(). So we do this first. If it succeeds we do almost twice
|
||
the work but this does not matter, since it is not for production
|
||
use. */
|
||
static const char preload_file[] = "/etc/ld.so.preload";
|
||
if (__glibc_unlikely (__access (preload_file, R_OK) == 0))
|
||
{
|
||
/* Read the contents of the file. */
|
||
file = _dl_sysdep_read_whole_file (preload_file, &file_size,
|
||
PROT_READ | PROT_WRITE);
|
||
if (__glibc_unlikely (file != MAP_FAILED))
|
||
{
|
||
/* Parse the file. It contains names of libraries to be loaded,
|
||
separated by white spaces or `:'. It may also contain
|
||
comments introduced by `#'. */
|
||
char *problem;
|
||
char *runp;
|
||
size_t rest;
|
||
|
||
/* Eliminate comments. */
|
||
runp = file;
|
||
rest = file_size;
|
||
while (rest > 0)
|
||
{
|
||
char *comment = memchr (runp, '#', rest);
|
||
if (comment == NULL)
|
||
break;
|
||
|
||
rest -= comment - runp;
|
||
do
|
||
*comment = ' ';
|
||
while (--rest > 0 && *++comment != '\n');
|
||
}
|
||
|
||
/* We have one problematic case: if we have a name at the end of
|
||
the file without a trailing terminating characters, we cannot
|
||
place the \0. Handle the case separately. */
|
||
if (file[file_size - 1] != ' ' && file[file_size - 1] != '\t'
|
||
&& file[file_size - 1] != '\n' && file[file_size - 1] != ':')
|
||
{
|
||
problem = &file[file_size];
|
||
while (problem > file && problem[-1] != ' '
|
||
&& problem[-1] != '\t'
|
||
&& problem[-1] != '\n' && problem[-1] != ':')
|
||
--problem;
|
||
|
||
if (problem > file)
|
||
problem[-1] = '\0';
|
||
}
|
||
else
|
||
{
|
||
problem = NULL;
|
||
file[file_size - 1] = '\0';
|
||
}
|
||
|
||
RTLD_TIMING_VAR (start);
|
||
rtld_timer_start (&start);
|
||
|
||
if (file != problem)
|
||
{
|
||
char *p;
|
||
runp = file;
|
||
while ((p = strsep (&runp, ": \t\n")) != NULL)
|
||
if (p[0] != '\0')
|
||
npreloads += do_preload (p, main_map, preload_file);
|
||
}
|
||
|
||
if (problem != NULL)
|
||
{
|
||
char *p = strndupa (problem, file_size - (problem - file));
|
||
|
||
npreloads += do_preload (p, main_map, preload_file);
|
||
}
|
||
|
||
rtld_timer_accum (&load_time, start);
|
||
|
||
/* We don't need the file anymore. */
|
||
__munmap (file, file_size);
|
||
}
|
||
}
|
||
|
||
if (__glibc_unlikely (*first_preload != NULL))
|
||
{
|
||
/* Set up PRELOADS with a vector of the preloaded libraries. */
|
||
struct link_map *l = *first_preload;
|
||
preloads = __alloca (npreloads * sizeof preloads[0]);
|
||
i = 0;
|
||
do
|
||
{
|
||
preloads[i++] = l;
|
||
l = l->l_next;
|
||
} while (l);
|
||
assert (i == npreloads);
|
||
}
|
||
|
||
#ifdef NEED_DL_SYSINFO_DSO
|
||
/* Now that the audit modules are opened, call la_objopen for the vDSO. */
|
||
if (GLRO(dl_sysinfo_map) != NULL)
|
||
_dl_audit_objopen (GLRO(dl_sysinfo_map), LM_ID_BASE);
|
||
#endif
|
||
|
||
/* Load all the libraries specified by DT_NEEDED entries. If LD_PRELOAD
|
||
specified some libraries to load, these are inserted before the actual
|
||
dependencies in the executable's searchlist for symbol resolution. */
|
||
{
|
||
RTLD_TIMING_VAR (start);
|
||
rtld_timer_start (&start);
|
||
_dl_map_object_deps (main_map, preloads, npreloads,
|
||
state.mode == rtld_mode_trace, 0);
|
||
rtld_timer_accum (&load_time, start);
|
||
}
|
||
|
||
/* Mark all objects as being in the global scope. */
|
||
for (i = main_map->l_searchlist.r_nlist; i > 0; )
|
||
main_map->l_searchlist.r_list[--i]->l_global = 1;
|
||
|
||
/* Remove _dl_rtld_map from the chain. */
|
||
GL(dl_rtld_map).l_prev->l_next = GL(dl_rtld_map).l_next;
|
||
if (GL(dl_rtld_map).l_next != NULL)
|
||
GL(dl_rtld_map).l_next->l_prev = GL(dl_rtld_map).l_prev;
|
||
|
||
for (i = 1; i < main_map->l_searchlist.r_nlist; ++i)
|
||
if (main_map->l_searchlist.r_list[i] == &GL(dl_rtld_map))
|
||
break;
|
||
|
||
/* Insert the link map for the dynamic loader into the chain in
|
||
symbol search order because gdb uses the chain's order as its
|
||
symbol search order. */
|
||
|
||
GL(dl_rtld_map).l_prev = main_map->l_searchlist.r_list[i - 1];
|
||
if (__glibc_likely (state.mode == rtld_mode_normal))
|
||
{
|
||
GL(dl_rtld_map).l_next = (i + 1 < main_map->l_searchlist.r_nlist
|
||
? main_map->l_searchlist.r_list[i + 1]
|
||
: NULL);
|
||
#ifdef NEED_DL_SYSINFO_DSO
|
||
if (GLRO(dl_sysinfo_map) != NULL
|
||
&& GL(dl_rtld_map).l_prev->l_next == GLRO(dl_sysinfo_map)
|
||
&& GL(dl_rtld_map).l_next != GLRO(dl_sysinfo_map))
|
||
GL(dl_rtld_map).l_prev = GLRO(dl_sysinfo_map);
|
||
#endif
|
||
}
|
||
else
|
||
/* In trace mode there might be an invisible object (which we
|
||
could not find) after the previous one in the search list.
|
||
In this case it doesn't matter much where we put the
|
||
interpreter object, so we just initialize the list pointer so
|
||
that the assertion below holds. */
|
||
GL(dl_rtld_map).l_next = GL(dl_rtld_map).l_prev->l_next;
|
||
|
||
assert (GL(dl_rtld_map).l_prev->l_next == GL(dl_rtld_map).l_next);
|
||
GL(dl_rtld_map).l_prev->l_next = &GL(dl_rtld_map);
|
||
if (GL(dl_rtld_map).l_next != NULL)
|
||
{
|
||
assert (GL(dl_rtld_map).l_next->l_prev == GL(dl_rtld_map).l_prev);
|
||
GL(dl_rtld_map).l_next->l_prev = &GL(dl_rtld_map);
|
||
}
|
||
|
||
/* Now let us see whether all libraries are available in the
|
||
versions we need. */
|
||
{
|
||
struct version_check_args args;
|
||
args.doexit = state.mode == rtld_mode_normal;
|
||
args.dotrace = state.mode == rtld_mode_trace;
|
||
_dl_receive_error (print_missing_version, version_check_doit, &args);
|
||
}
|
||
|
||
/* We do not initialize any of the TLS functionality unless any of the
|
||
initial modules uses TLS. This makes dynamic loading of modules with
|
||
TLS impossible, but to support it requires either eagerly doing setup
|
||
now or lazily doing it later. Doing it now makes us incompatible with
|
||
an old kernel that can't perform TLS_INIT_TP, even if no TLS is ever
|
||
used. Trying to do it lazily is too hairy to try when there could be
|
||
multiple threads (from a non-TLS-using libpthread). */
|
||
bool was_tls_init_tp_called = __rtld_tls_init_tp_called;
|
||
if (tcbp == NULL)
|
||
tcbp = init_tls (0);
|
||
|
||
if (__glibc_likely (need_security_init))
|
||
/* Initialize security features. But only if we have not done it
|
||
earlier. */
|
||
security_init ();
|
||
|
||
if (__glibc_unlikely (state.mode != rtld_mode_normal))
|
||
{
|
||
/* We were run just to list the shared libraries. It is
|
||
important that we do this before real relocation, because the
|
||
functions we call below for output may no longer work properly
|
||
after relocation. */
|
||
struct link_map *l;
|
||
|
||
if (GLRO(dl_debug_mask) & DL_DEBUG_UNUSED)
|
||
{
|
||
/* Look through the dependencies of the main executable
|
||
and determine which of them is not actually
|
||
required. */
|
||
struct link_map *l = main_map;
|
||
|
||
/* Relocate the main executable. */
|
||
struct relocate_args args = { .l = l,
|
||
.reloc_mode = ((GLRO(dl_lazy)
|
||
? RTLD_LAZY : 0)
|
||
| __RTLD_NOIFUNC) };
|
||
_dl_receive_error (print_unresolved, relocate_doit, &args);
|
||
|
||
/* This loop depends on the dependencies of the executable to
|
||
correspond in number and order to the DT_NEEDED entries. */
|
||
ElfW(Dyn) *dyn = main_map->l_ld;
|
||
bool first = true;
|
||
while (dyn->d_tag != DT_NULL)
|
||
{
|
||
if (dyn->d_tag == DT_NEEDED)
|
||
{
|
||
l = l->l_next;
|
||
#ifdef NEED_DL_SYSINFO_DSO
|
||
/* Skip the VDSO since it's not part of the list
|
||
of objects we brought in via DT_NEEDED entries. */
|
||
if (l == GLRO(dl_sysinfo_map))
|
||
l = l->l_next;
|
||
#endif
|
||
if (!l->l_used)
|
||
{
|
||
if (first)
|
||
{
|
||
_dl_printf ("Unused direct dependencies:\n");
|
||
first = false;
|
||
}
|
||
|
||
_dl_printf ("\t%s\n", l->l_name);
|
||
}
|
||
}
|
||
|
||
++dyn;
|
||
}
|
||
|
||
_exit (first != true);
|
||
}
|
||
else if (! main_map->l_info[DT_NEEDED])
|
||
_dl_printf ("\tstatically linked\n");
|
||
else
|
||
{
|
||
for (l = state.mode_trace_program ? main_map : main_map->l_next;
|
||
l; l = l->l_next) {
|
||
if (l->l_faked)
|
||
/* The library was not found. */
|
||
_dl_printf ("\t%s => not found\n", l->l_libname->name);
|
||
else if (strcmp (l->l_libname->name, l->l_name) == 0)
|
||
/* Print vDSO like libraries without duplicate name. Some
|
||
consumers depend of this format. */
|
||
_dl_printf ("\t%s (0x%0*zx)\n", l->l_libname->name,
|
||
(int) sizeof l->l_map_start * 2,
|
||
(size_t) l->l_map_start);
|
||
else
|
||
_dl_printf ("\t%s => %s (0x%0*zx)\n",
|
||
DSO_FILENAME (l->l_libname->name),
|
||
DSO_FILENAME (l->l_name),
|
||
(int) sizeof l->l_map_start * 2,
|
||
(size_t) l->l_map_start);
|
||
}
|
||
}
|
||
|
||
if (__glibc_unlikely (state.mode != rtld_mode_trace))
|
||
for (i = 1; i < (unsigned int) _dl_argc; ++i)
|
||
{
|
||
const ElfW(Sym) *ref = NULL;
|
||
ElfW(Addr) loadbase;
|
||
lookup_t result;
|
||
|
||
result = _dl_lookup_symbol_x (_dl_argv[i], main_map,
|
||
&ref, main_map->l_scope,
|
||
NULL, ELF_RTYPE_CLASS_PLT,
|
||
DL_LOOKUP_ADD_DEPENDENCY, NULL);
|
||
|
||
loadbase = LOOKUP_VALUE_ADDRESS (result, false);
|
||
|
||
_dl_printf ("%s found at 0x%0*zd in object at 0x%0*zd\n",
|
||
_dl_argv[i],
|
||
(int) sizeof ref->st_value * 2,
|
||
(size_t) ref->st_value,
|
||
(int) sizeof loadbase * 2, (size_t) loadbase);
|
||
}
|
||
else
|
||
{
|
||
/* If LD_WARN is set, warn about undefined symbols. */
|
||
if (GLRO(dl_lazy) >= 0 && GLRO(dl_verbose))
|
||
{
|
||
/* We have to do symbol dependency testing. */
|
||
struct relocate_args args;
|
||
unsigned int i;
|
||
|
||
args.reloc_mode = ((GLRO(dl_lazy) ? RTLD_LAZY : 0)
|
||
| __RTLD_NOIFUNC);
|
||
|
||
i = main_map->l_searchlist.r_nlist;
|
||
while (i-- > 0)
|
||
{
|
||
struct link_map *l = main_map->l_initfini[i];
|
||
if (l != &GL(dl_rtld_map) && ! l->l_faked)
|
||
{
|
||
args.l = l;
|
||
_dl_receive_error (print_unresolved, relocate_doit,
|
||
&args);
|
||
}
|
||
}
|
||
|
||
}
|
||
#define VERNEEDTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (DT_VERNEED))
|
||
if (state.version_info)
|
||
{
|
||
/* Print more information. This means here, print information
|
||
about the versions needed. */
|
||
int first = 1;
|
||
struct link_map *map;
|
||
|
||
for (map = main_map; map != NULL; map = map->l_next)
|
||
{
|
||
const char *strtab;
|
||
ElfW(Dyn) *dyn = map->l_info[VERNEEDTAG];
|
||
ElfW(Verneed) *ent;
|
||
|
||
if (dyn == NULL)
|
||
continue;
|
||
|
||
strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
|
||
ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);
|
||
|
||
if (first)
|
||
{
|
||
_dl_printf ("\n\tVersion information:\n");
|
||
first = 0;
|
||
}
|
||
|
||
_dl_printf ("\t%s:\n", DSO_FILENAME (map->l_name));
|
||
|
||
while (1)
|
||
{
|
||
ElfW(Vernaux) *aux;
|
||
struct link_map *needed;
|
||
|
||
needed = find_needed (strtab + ent->vn_file);
|
||
aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);
|
||
|
||
while (1)
|
||
{
|
||
const char *fname = NULL;
|
||
|
||
if (needed != NULL
|
||
&& match_version (strtab + aux->vna_name,
|
||
needed))
|
||
fname = needed->l_name;
|
||
|
||
_dl_printf ("\t\t%s (%s) %s=> %s\n",
|
||
strtab + ent->vn_file,
|
||
strtab + aux->vna_name,
|
||
aux->vna_flags & VER_FLG_WEAK
|
||
? "[WEAK] " : "",
|
||
fname ?: "not found");
|
||
|
||
if (aux->vna_next == 0)
|
||
/* No more symbols. */
|
||
break;
|
||
|
||
/* Next symbol. */
|
||
aux = (ElfW(Vernaux) *) ((char *) aux
|
||
+ aux->vna_next);
|
||
}
|
||
|
||
if (ent->vn_next == 0)
|
||
/* No more dependencies. */
|
||
break;
|
||
|
||
/* Next dependency. */
|
||
ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
_exit (0);
|
||
}
|
||
|
||
/* Now set up the variable which helps the assembler startup code. */
|
||
GL(dl_ns)[LM_ID_BASE]._ns_main_searchlist = &main_map->l_searchlist;
|
||
|
||
/* Save the information about the original global scope list since
|
||
we need it in the memory handling later. */
|
||
GLRO(dl_initial_searchlist) = *GL(dl_ns)[LM_ID_BASE]._ns_main_searchlist;
|
||
|
||
/* Remember the last search directory added at startup, now that
|
||
malloc will no longer be the one from dl-minimal.c. As a side
|
||
effect, this marks ld.so as initialized, so that the rtld_active
|
||
function returns true from now on. */
|
||
GLRO(dl_init_all_dirs) = GL(dl_all_dirs);
|
||
|
||
/* Print scope information. */
|
||
if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES))
|
||
{
|
||
_dl_debug_printf ("\nInitial object scopes\n");
|
||
|
||
for (struct link_map *l = main_map; l != NULL; l = l->l_next)
|
||
_dl_show_scope (l, 0);
|
||
}
|
||
|
||
_rtld_main_check (main_map, _dl_argv[0]);
|
||
|
||
/* Now we have all the objects loaded. Relocate them all except for
|
||
the dynamic linker itself. We do this in reverse order so that copy
|
||
relocs of earlier objects overwrite the data written by later
|
||
objects. We do not re-relocate the dynamic linker itself in this
|
||
loop because that could result in the GOT entries for functions we
|
||
call being changed, and that would break us. It is safe to relocate
|
||
the dynamic linker out of order because it has no copy relocations.
|
||
Likewise for libc, which is relocated early to ensure that IFUNC
|
||
resolvers in libc work. */
|
||
|
||
int consider_profiling = GLRO(dl_profile) != NULL;
|
||
|
||
/* If we are profiling we also must do lazy reloaction. */
|
||
GLRO(dl_lazy) |= consider_profiling;
|
||
|
||
if (GL(dl_ns)[LM_ID_BASE].libc_map != NULL)
|
||
_dl_relocate_object (GL(dl_ns)[LM_ID_BASE].libc_map,
|
||
GL(dl_ns)[LM_ID_BASE].libc_map->l_scope,
|
||
GLRO(dl_lazy) ? RTLD_LAZY : 0, consider_profiling);
|
||
|
||
RTLD_TIMING_VAR (start);
|
||
rtld_timer_start (&start);
|
||
{
|
||
unsigned i = main_map->l_searchlist.r_nlist;
|
||
while (i-- > 0)
|
||
{
|
||
struct link_map *l = main_map->l_initfini[i];
|
||
|
||
/* While we are at it, help the memory handling a bit. We have to
|
||
mark some data structures as allocated with the fake malloc()
|
||
implementation in ld.so. */
|
||
struct libname_list *lnp = l->l_libname->next;
|
||
|
||
while (__builtin_expect (lnp != NULL, 0))
|
||
{
|
||
lnp->dont_free = 1;
|
||
lnp = lnp->next;
|
||
}
|
||
/* Also allocated with the fake malloc(). */
|
||
l->l_free_initfini = 0;
|
||
|
||
if (l != &GL(dl_rtld_map))
|
||
_dl_relocate_object (l, l->l_scope, GLRO(dl_lazy) ? RTLD_LAZY : 0,
|
||
consider_profiling);
|
||
|
||
/* Add object to slot information data if necessasy. */
|
||
if (l->l_tls_blocksize != 0 && __rtld_tls_init_tp_called)
|
||
_dl_add_to_slotinfo (l, true);
|
||
}
|
||
}
|
||
rtld_timer_stop (&relocate_time, start);
|
||
|
||
/* Now enable profiling if needed. Like the previous call,
|
||
this has to go here because the calls it makes should use the
|
||
rtld versions of the functions (particularly calloc()), but it
|
||
needs to have _dl_profile_map set up by the relocator. */
|
||
if (__glibc_unlikely (GL(dl_profile_map) != NULL))
|
||
/* We must prepare the profiling. */
|
||
_dl_start_profile ();
|
||
|
||
if ((!was_tls_init_tp_called && GL(dl_tls_max_dtv_idx) > 0)
|
||
|| count_modids != _dl_count_modids ())
|
||
++GL(dl_tls_generation);
|
||
|
||
/* Now that we have completed relocation, the initializer data
|
||
for the TLS blocks has its final values and we can copy them
|
||
into the main thread's TLS area, which we allocated above.
|
||
Note: thread-local variables must only be accessed after completing
|
||
the next step. */
|
||
_dl_allocate_tls_init (tcbp, true);
|
||
|
||
/* And finally install it for the main thread. */
|
||
if (! __rtld_tls_init_tp_called)
|
||
call_tls_init_tp (tcbp);
|
||
|
||
/* Make sure no new search directories have been added. */
|
||
assert (GLRO(dl_init_all_dirs) == GL(dl_all_dirs));
|
||
|
||
/* Re-relocate ourselves with user-controlled symbol definitions.
|
||
|
||
We must do this after TLS initialization in case after this
|
||
re-relocation, we might call a user-supplied function
|
||
(e.g. calloc from _dl_relocate_object) that uses TLS data. */
|
||
|
||
/* Set up the object lookup structures. */
|
||
_dl_find_object_init ();
|
||
|
||
/* The malloc implementation has been relocated, so resolving
|
||
its symbols (and potentially calling IFUNC resolvers) is safe
|
||
at this point. */
|
||
__rtld_malloc_init_real (main_map);
|
||
|
||
/* Likewise for the locking implementation. */
|
||
__rtld_mutex_init ();
|
||
|
||
{
|
||
RTLD_TIMING_VAR (start);
|
||
rtld_timer_start (&start);
|
||
|
||
/* Mark the link map as not yet relocated again. */
|
||
GL(dl_rtld_map).l_relocated = 0;
|
||
_dl_relocate_object (&GL(dl_rtld_map), main_map->l_scope, 0, 0);
|
||
|
||
rtld_timer_accum (&relocate_time, start);
|
||
}
|
||
|
||
/* Relocation is complete. Perform early libc initialization. This
|
||
is the initial libc, even if audit modules have been loaded with
|
||
other libcs. */
|
||
_dl_call_libc_early_init (GL(dl_ns)[LM_ID_BASE].libc_map, true);
|
||
|
||
/* Do any necessary cleanups for the startup OS interface code.
|
||
We do these now so that no calls are made after rtld re-relocation
|
||
which might be resolved to different functions than we expect.
|
||
We cannot do this before relocating the other objects because
|
||
_dl_relocate_object might need to call `mprotect' for DT_TEXTREL. */
|
||
_dl_sysdep_start_cleanup ();
|
||
|
||
/* Notify the debugger all new objects are now ready to go. We must re-get
|
||
the address since by now the variable might be in another object. */
|
||
r = _dl_debug_update (LM_ID_BASE);
|
||
r->r_state = RT_CONSISTENT;
|
||
_dl_debug_state ();
|
||
LIBC_PROBE (init_complete, 2, LM_ID_BASE, r);
|
||
|
||
/* Auditing checkpoint: we have added all objects. */
|
||
_dl_audit_activity_nsid (LM_ID_BASE, LA_ACT_CONSISTENT);
|
||
|
||
#if defined USE_LDCONFIG && !defined MAP_COPY
|
||
/* We must munmap() the cache file. */
|
||
_dl_unload_cache ();
|
||
#endif
|
||
|
||
/* Once we return, _dl_sysdep_start will invoke
|
||
the DT_INIT functions and then *USER_ENTRY. */
|
||
}
|
||
|
||
/* This is a little helper function for resolving symbols while
|
||
tracing the binary. */
|
||
static void
|
||
print_unresolved (int errcode __attribute__ ((unused)), const char *objname,
|
||
const char *errstring)
|
||
{
|
||
if (objname[0] == '\0')
|
||
objname = RTLD_PROGNAME;
|
||
_dl_error_printf ("%s (%s)\n", errstring, objname);
|
||
}
|
||
|
||
/* This is a little helper function for resolving symbols while
|
||
tracing the binary. */
|
||
static void
|
||
print_missing_version (int errcode __attribute__ ((unused)),
|
||
const char *objname, const char *errstring)
|
||
{
|
||
_dl_error_printf ("%s: %s: %s\n", RTLD_PROGNAME,
|
||
objname, errstring);
|
||
}
|
||
|
||
/* Process the string given as the parameter which explains which debugging
|
||
options are enabled. */
|
||
static void
|
||
process_dl_debug (struct dl_main_state *state, const char *dl_debug)
|
||
{
|
||
/* When adding new entries make sure that the maximal length of a name
|
||
is correctly handled in the LD_DEBUG_HELP code below. */
|
||
static const struct
|
||
{
|
||
unsigned char len;
|
||
const char name[10];
|
||
const char helptext[41];
|
||
unsigned short int mask;
|
||
} debopts[] =
|
||
{
|
||
#define LEN_AND_STR(str) sizeof (str) - 1, str
|
||
{ LEN_AND_STR ("libs"), "display library search paths",
|
||
DL_DEBUG_LIBS | DL_DEBUG_IMPCALLS },
|
||
{ LEN_AND_STR ("reloc"), "display relocation processing",
|
||
DL_DEBUG_RELOC | DL_DEBUG_IMPCALLS },
|
||
{ LEN_AND_STR ("files"), "display progress for input file",
|
||
DL_DEBUG_FILES | DL_DEBUG_IMPCALLS },
|
||
{ LEN_AND_STR ("symbols"), "display symbol table processing",
|
||
DL_DEBUG_SYMBOLS | DL_DEBUG_IMPCALLS },
|
||
{ LEN_AND_STR ("bindings"), "display information about symbol binding",
|
||
DL_DEBUG_BINDINGS | DL_DEBUG_IMPCALLS },
|
||
{ LEN_AND_STR ("versions"), "display version dependencies",
|
||
DL_DEBUG_VERSIONS | DL_DEBUG_IMPCALLS },
|
||
{ LEN_AND_STR ("scopes"), "display scope information",
|
||
DL_DEBUG_SCOPES },
|
||
{ LEN_AND_STR ("all"), "all previous options combined",
|
||
DL_DEBUG_LIBS | DL_DEBUG_RELOC | DL_DEBUG_FILES | DL_DEBUG_SYMBOLS
|
||
| DL_DEBUG_BINDINGS | DL_DEBUG_VERSIONS | DL_DEBUG_IMPCALLS
|
||
| DL_DEBUG_SCOPES },
|
||
{ LEN_AND_STR ("statistics"), "display relocation statistics",
|
||
DL_DEBUG_STATISTICS },
|
||
{ LEN_AND_STR ("unused"), "determined unused DSOs",
|
||
DL_DEBUG_UNUSED },
|
||
{ LEN_AND_STR ("help"), "display this help message and exit",
|
||
DL_DEBUG_HELP },
|
||
};
|
||
#define ndebopts (sizeof (debopts) / sizeof (debopts[0]))
|
||
|
||
/* Skip separating white spaces and commas. */
|
||
while (*dl_debug != '\0')
|
||
{
|
||
if (*dl_debug != ' ' && *dl_debug != ',' && *dl_debug != ':')
|
||
{
|
||
size_t cnt;
|
||
size_t len = 1;
|
||
|
||
while (dl_debug[len] != '\0' && dl_debug[len] != ' '
|
||
&& dl_debug[len] != ',' && dl_debug[len] != ':')
|
||
++len;
|
||
|
||
for (cnt = 0; cnt < ndebopts; ++cnt)
|
||
if (debopts[cnt].len == len
|
||
&& memcmp (dl_debug, debopts[cnt].name, len) == 0)
|
||
{
|
||
GLRO(dl_debug_mask) |= debopts[cnt].mask;
|
||
break;
|
||
}
|
||
|
||
if (cnt == ndebopts)
|
||
{
|
||
/* Display a warning and skip everything until next
|
||
separator. */
|
||
char *copy = strndupa (dl_debug, len);
|
||
_dl_error_printf ("\
|
||
warning: debug option `%s' unknown; try LD_DEBUG=help\n", copy);
|
||
}
|
||
|
||
dl_debug += len;
|
||
continue;
|
||
}
|
||
|
||
++dl_debug;
|
||
}
|
||
|
||
if (GLRO(dl_debug_mask) & DL_DEBUG_UNUSED)
|
||
{
|
||
/* In order to get an accurate picture of whether a particular
|
||
DT_NEEDED entry is actually used we have to process both
|
||
the PLT and non-PLT relocation entries. */
|
||
GLRO(dl_lazy) = 0;
|
||
}
|
||
|
||
if (GLRO(dl_debug_mask) & DL_DEBUG_HELP)
|
||
{
|
||
size_t cnt;
|
||
|
||
_dl_printf ("\
|
||
Valid options for the LD_DEBUG environment variable are:\n\n");
|
||
|
||
for (cnt = 0; cnt < ndebopts; ++cnt)
|
||
_dl_printf (" %.*s%s%s\n", debopts[cnt].len, debopts[cnt].name,
|
||
" " + debopts[cnt].len - 3,
|
||
debopts[cnt].helptext);
|
||
|
||
_dl_printf ("\n\
|
||
To direct the debugging output into a file instead of standard output\n\
|
||
a filename can be specified using the LD_DEBUG_OUTPUT environment variable.\n");
|
||
_exit (0);
|
||
}
|
||
}
|
||
|
||
static int
|
||
process_envvars_secure (struct dl_main_state *state)
|
||
{
|
||
char **runp = _environ;
|
||
char *envline;
|
||
int skip_env = 0;
|
||
|
||
while ((envline = _dl_next_ld_env_entry (&runp)) != NULL)
|
||
{
|
||
size_t len = 0;
|
||
|
||
while (envline[len] != '\0' && envline[len] != '=')
|
||
++len;
|
||
|
||
if (envline[len] != '=')
|
||
/* This is a "LD_" variable at the end of the string without
|
||
a '=' character. Ignore it since otherwise we will access
|
||
invalid memory below. */
|
||
continue;
|
||
|
||
switch (len)
|
||
{
|
||
case 5:
|
||
/* For __libc_enable_secure mode, audit pathnames containing slashes
|
||
are ignored. Also, shared audit objects are only loaded only from
|
||
the standard search directories and only if they have set-user-ID
|
||
mode bit enabled. */
|
||
if (memcmp (envline, "AUDIT", 5) == 0)
|
||
audit_list_add_string (&state->audit_list, &envline[6]);
|
||
break;
|
||
|
||
case 7:
|
||
/* For __libc_enable_secure mode, preload pathnames containing slashes
|
||
are ignored. Also, shared objects are only preloaded from the
|
||
standard search directories and only if they have set-user-ID mode
|
||
bit enabled. */
|
||
if (memcmp (envline, "PRELOAD", 7) == 0)
|
||
state->preloadlist = &envline[8];
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* Extra security for SUID binaries. Remove all dangerous environment
|
||
variables. */
|
||
const char *nextp = UNSECURE_ENVVARS;
|
||
do
|
||
{
|
||
/* Keep track of the number of environment variables that were set in
|
||
the environment and are unset below. Use getenv() which returns
|
||
non-NULL if the variable is set in the environment. This count is
|
||
needed if we need to adjust the location of the AUX vector on the
|
||
stack when running ld.so directly. */
|
||
if (getenv (nextp) != NULL)
|
||
skip_env++;
|
||
|
||
unsetenv (nextp);
|
||
nextp = strchr (nextp, '\0') + 1;
|
||
}
|
||
while (*nextp != '\0');
|
||
|
||
if (GLRO(dl_debug_mask) != 0
|
||
|| GLRO(dl_verbose) != 0
|
||
|| GLRO(dl_lazy) != 1
|
||
|| GLRO(dl_bind_not) != 0
|
||
|| state->mode != rtld_mode_normal
|
||
|| state->version_info)
|
||
_exit (5);
|
||
|
||
return skip_env;
|
||
}
|
||
|
||
static void
|
||
process_envvars_default (struct dl_main_state *state)
|
||
{
|
||
char **runp = _environ;
|
||
char *envline;
|
||
char *debug_output = NULL;
|
||
|
||
while ((envline = _dl_next_ld_env_entry (&runp)) != NULL)
|
||
{
|
||
size_t len = 0;
|
||
|
||
while (envline[len] != '\0' && envline[len] != '=')
|
||
++len;
|
||
|
||
if (envline[len] != '=')
|
||
/* This is a "LD_" variable at the end of the string without
|
||
a '=' character. Ignore it since otherwise we will access
|
||
invalid memory below. */
|
||
continue;
|
||
|
||
switch (len)
|
||
{
|
||
case 4:
|
||
/* Warning level, verbose or not. */
|
||
if (memcmp (envline, "WARN", 4) == 0)
|
||
GLRO(dl_verbose) = envline[5] != '\0';
|
||
break;
|
||
|
||
case 5:
|
||
/* Debugging of the dynamic linker? */
|
||
if (memcmp (envline, "DEBUG", 5) == 0)
|
||
{
|
||
process_dl_debug (state, &envline[6]);
|
||
break;
|
||
}
|
||
/* For __libc_enable_secure mode, audit pathnames containing slashes
|
||
are ignored. Also, shared audit objects are only loaded only from
|
||
the standard search directories and only if they have set-user-ID
|
||
mode bit enabled. */
|
||
if (memcmp (envline, "AUDIT", 5) == 0)
|
||
audit_list_add_string (&state->audit_list, &envline[6]);
|
||
break;
|
||
|
||
case 7:
|
||
/* Print information about versions. */
|
||
if (memcmp (envline, "VERBOSE", 7) == 0)
|
||
{
|
||
state->version_info = envline[8] != '\0';
|
||
break;
|
||
}
|
||
|
||
/* For __libc_enable_secure mode, preload pathnames containing slashes
|
||
are ignored. Also, shared objects are only preloaded from the
|
||
standard search directories and only if they have set-user-ID mode
|
||
bit enabled. */
|
||
if (memcmp (envline, "PRELOAD", 7) == 0)
|
||
{
|
||
state->preloadlist = &envline[8];
|
||
break;
|
||
}
|
||
|
||
/* Which shared object shall be profiled. */
|
||
if (memcmp (envline, "PROFILE", 7) == 0 && envline[8] != '\0')
|
||
GLRO(dl_profile) = &envline[8];
|
||
break;
|
||
|
||
case 8:
|
||
/* Do we bind early? */
|
||
if (memcmp (envline, "BIND_NOW", 8) == 0)
|
||
{
|
||
GLRO(dl_lazy) = envline[9] == '\0';
|
||
break;
|
||
}
|
||
if (memcmp (envline, "BIND_NOT", 8) == 0)
|
||
GLRO(dl_bind_not) = envline[9] != '\0';
|
||
break;
|
||
|
||
case 9:
|
||
/* Test whether we want to see the content of the auxiliary
|
||
array passed up from the kernel. */
|
||
if (memcmp (envline, "SHOW_AUXV", 9) == 0)
|
||
_dl_show_auxv ();
|
||
break;
|
||
|
||
case 11:
|
||
/* Path where the binary is found. */
|
||
if (memcmp (envline, "ORIGIN_PATH", 11) == 0)
|
||
GLRO(dl_origin_path) = &envline[12];
|
||
break;
|
||
|
||
case 12:
|
||
/* The library search path. */
|
||
if (memcmp (envline, "LIBRARY_PATH", 12) == 0)
|
||
{
|
||
state->library_path = &envline[13];
|
||
state->library_path_source = "LD_LIBRARY_PATH";
|
||
break;
|
||
}
|
||
|
||
/* Where to place the profiling data file. */
|
||
if (memcmp (envline, "DEBUG_OUTPUT", 12) == 0)
|
||
{
|
||
debug_output = &envline[13];
|
||
break;
|
||
}
|
||
|
||
if (memcmp (envline, "DYNAMIC_WEAK", 12) == 0)
|
||
GLRO(dl_dynamic_weak) = 1;
|
||
break;
|
||
|
||
case 14:
|
||
/* Where to place the profiling data file. */
|
||
if (memcmp (envline, "PROFILE_OUTPUT", 14) == 0
|
||
&& envline[15] != '\0')
|
||
GLRO(dl_profile_output) = &envline[15];
|
||
break;
|
||
|
||
case 20:
|
||
/* The mode of the dynamic linker can be set. */
|
||
if (memcmp (envline, "TRACE_LOADED_OBJECTS", 20) == 0)
|
||
{
|
||
state->mode = rtld_mode_trace;
|
||
state->mode_trace_program
|
||
= _dl_strtoul (&envline[21], NULL) > 1;
|
||
}
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* If we have to run the dynamic linker in debugging mode and the
|
||
LD_DEBUG_OUTPUT environment variable is given, we write the debug
|
||
messages to this file. */
|
||
if (GLRO(dl_debug_mask) != 0 && debug_output != NULL)
|
||
{
|
||
const int flags = O_WRONLY | O_APPEND | O_CREAT | O_NOFOLLOW;
|
||
size_t name_len = strlen (debug_output);
|
||
char buf[name_len + 12];
|
||
char *startp;
|
||
|
||
buf[name_len + 11] = '\0';
|
||
startp = _itoa (__getpid (), &buf[name_len + 11], 10, 0);
|
||
*--startp = '.';
|
||
startp = memcpy (startp - name_len, debug_output, name_len);
|
||
|
||
GLRO(dl_debug_fd) = __open64_nocancel (startp, flags, DEFFILEMODE);
|
||
if (GLRO(dl_debug_fd) == -1)
|
||
/* We use standard output if opening the file failed. */
|
||
GLRO(dl_debug_fd) = STDOUT_FILENO;
|
||
}
|
||
}
|
||
|
||
static int
|
||
process_envvars (struct dl_main_state *state)
|
||
{
|
||
int skip_env = 0;
|
||
if (__glibc_unlikely (__libc_enable_secure))
|
||
skip_env += process_envvars_secure (state);
|
||
else
|
||
process_envvars_default (state);
|
||
|
||
return skip_env;
|
||
}
|
||
|
||
#if HP_TIMING_INLINE
|
||
static void
|
||
print_statistics_item (const char *title, hp_timing_t time,
|
||
hp_timing_t total)
|
||
{
|
||
char cycles[HP_TIMING_PRINT_SIZE];
|
||
HP_TIMING_PRINT (cycles, sizeof (cycles), time);
|
||
|
||
char relative[3 * sizeof (hp_timing_t) + 2];
|
||
char *cp = _itoa ((1000ULL * time) / total, relative + sizeof (relative),
|
||
10, 0);
|
||
/* Sets the decimal point. */
|
||
char *wp = relative;
|
||
switch (relative + sizeof (relative) - cp)
|
||
{
|
||
case 3:
|
||
*wp++ = *cp++;
|
||
/* Fall through. */
|
||
case 2:
|
||
*wp++ = *cp++;
|
||
/* Fall through. */
|
||
case 1:
|
||
*wp++ = '.';
|
||
*wp++ = *cp++;
|
||
}
|
||
*wp = '\0';
|
||
_dl_debug_printf ("%s: %s cycles (%s%%)\n", title, cycles, relative);
|
||
}
|
||
#endif
|
||
|
||
/* Print the various times we collected. */
|
||
static void
|
||
__attribute ((noinline))
|
||
print_statistics (const hp_timing_t *rtld_total_timep)
|
||
{
|
||
#if HP_TIMING_INLINE
|
||
{
|
||
char cycles[HP_TIMING_PRINT_SIZE];
|
||
HP_TIMING_PRINT (cycles, sizeof (cycles), *rtld_total_timep);
|
||
_dl_debug_printf ("\nruntime linker statistics:\n"
|
||
" total startup time in dynamic loader: %s cycles\n",
|
||
cycles);
|
||
print_statistics_item (" time needed for relocation",
|
||
relocate_time, *rtld_total_timep);
|
||
}
|
||
#endif
|
||
|
||
unsigned long int num_relative_relocations = 0;
|
||
for (Lmid_t ns = 0; ns < GL(dl_nns); ++ns)
|
||
{
|
||
if (GL(dl_ns)[ns]._ns_loaded == NULL)
|
||
continue;
|
||
|
||
struct r_scope_elem *scope = &GL(dl_ns)[ns]._ns_loaded->l_searchlist;
|
||
|
||
for (unsigned int i = 0; i < scope->r_nlist; i++)
|
||
{
|
||
struct link_map *l = scope->r_list [i];
|
||
|
||
if (l->l_addr != 0 && l->l_info[VERSYMIDX (DT_RELCOUNT)])
|
||
num_relative_relocations
|
||
+= l->l_info[VERSYMIDX (DT_RELCOUNT)]->d_un.d_val;
|
||
#ifndef ELF_MACHINE_REL_RELATIVE
|
||
/* Relative relocations are always processed on these
|
||
architectures. */
|
||
if (l->l_info[VERSYMIDX (DT_RELACOUNT)])
|
||
#else
|
||
/* On e.g. IA-64 or Alpha, relative relocations are processed
|
||
only if library is loaded to different address than p_vaddr. */
|
||
if (l->l_addr != 0 && l->l_info[VERSYMIDX (DT_RELACOUNT)])
|
||
#endif
|
||
num_relative_relocations
|
||
+= l->l_info[VERSYMIDX (DT_RELACOUNT)]->d_un.d_val;
|
||
}
|
||
}
|
||
|
||
_dl_debug_printf (" number of relocations: %lu\n"
|
||
" number of relocations from cache: %lu\n"
|
||
" number of relative relocations: %lu\n",
|
||
GL(dl_num_relocations),
|
||
GL(dl_num_cache_relocations),
|
||
num_relative_relocations);
|
||
|
||
#if HP_TIMING_INLINE
|
||
print_statistics_item (" time needed to load objects",
|
||
load_time, *rtld_total_timep);
|
||
#endif
|
||
}
|