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88677348b4
They are both used by __libc_freeres to free all library malloc allocated resources to help tooling like mtrace or valgrind with memory leak tracking. The current scheme uses assembly markers and linker script entries to consolidate the free routine function pointers in the RELRO segment and to be freed buffers in BSS. This patch changes it to use specific free functions for libc_freeres_ptrs buffers and call the function pointer array directly with call_function_static_weak. It allows the removal of both the internal macros and the linker script sections. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
183 lines
4.8 KiB
C
183 lines
4.8 KiB
C
/* Copyright (C) 1996-2023 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 <assert.h>
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#include <errno.h>
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#include <libc-lock.h>
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#include <stdlib.h>
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#include <resolv.h>
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#include <set-freeres.h>
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#include "nsswitch.h"
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/*******************************************************************\
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|* Here we assume several symbols to be defined: *|
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|* *|
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|* LOOKUP_TYPE - the return type of the function *|
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|* *|
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|* FUNCTION_NAME - name of the non-reentrant function *|
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|* *|
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|* DATABASE_NAME - name of the database the function accesses *|
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|* (e.g., host, services, ...) *|
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|* *|
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|* ADD_PARAMS - additional parameter, can vary in number *|
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|* *|
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|* ADD_VARIABLES - names of additional parameter *|
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|* *|
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|* BUFLEN - length of buffer allocated for the non *|
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|* reentrant version *|
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|* *|
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|* Optionally the following vars can be defined: *|
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|* *|
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|* NEED_H_ERRNO - an extra parameter will be passed to point to *|
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|* the global `h_errno' variable. *|
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|* *|
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\*******************************************************************/
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#ifdef HANDLE_DIGITS_DOTS
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# include <resolv/resolv_context.h>
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#endif
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/* To make the real sources a bit prettier. */
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#define REENTRANT_NAME APPEND_R (FUNCTION_NAME)
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#define APPEND_R(name) APPEND_R1 (name)
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#define APPEND_R1(name) name##_r
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#define INTERNAL(name) INTERNAL1 (name)
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#define INTERNAL1(name) __##name
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#define APPEND_FREEMEM_NAME1(name) __libc_##name##_freemem_ptr
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#define APPEND_FREEMEM_NAME(name) APPEND_FREEMEM_NAME1(name)
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#define FREEMEM_NAME APPEND_FREEMEM_NAME (FUNCTION_NAME)
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/* Sometimes we need to store error codes in the `h_errno' variable. */
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#ifdef NEED_H_ERRNO
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# define H_ERRNO_PARM , int *h_errnop
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# define H_ERRNO_VAR , &h_errno_tmp
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# define H_ERRNO_VAR_P &h_errno_tmp
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#else
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# define H_ERRNO_PARM
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# define H_ERRNO_VAR
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# define H_ERRNO_VAR_P NULL
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#endif
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#ifdef HAVE_AF
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# define AF_VAL af
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#else
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# define AF_VAL AF_INET
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#endif
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/* Prototype for reentrant version we use here. */
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extern int INTERNAL (REENTRANT_NAME) (ADD_PARAMS, LOOKUP_TYPE *resbuf,
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char *buffer, size_t buflen,
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LOOKUP_TYPE **result H_ERRNO_PARM)
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attribute_hidden;
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/* We need to protect the dynamic buffer handling. */
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__libc_lock_define_initialized (static, lock);
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/* This points to the static buffer used. */
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static char *buffer;
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weak_alias (buffer, FREEMEM_NAME)
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LOOKUP_TYPE *
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FUNCTION_NAME (ADD_PARAMS)
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{
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static size_t buffer_size;
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static LOOKUP_TYPE resbuf;
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LOOKUP_TYPE *result;
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#ifdef NEED_H_ERRNO
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int h_errno_tmp = 0;
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#endif
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#ifdef HANDLE_DIGITS_DOTS
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/* Wrap both __nss_hostname_digits_dots and the actual lookup
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function call in the same context. */
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struct resolv_context *res_ctx = __resolv_context_get ();
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if (res_ctx == NULL)
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{
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# if NEED_H_ERRNO
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__set_h_errno (NETDB_INTERNAL);
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# endif
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return NULL;
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}
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#endif
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/* Get lock. */
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__libc_lock_lock (lock);
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if (buffer == NULL)
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{
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buffer_size = BUFLEN;
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buffer = (char *) malloc (buffer_size);
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}
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#ifdef HANDLE_DIGITS_DOTS
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if (buffer != NULL)
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{
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if (__nss_hostname_digits_dots_context
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(res_ctx, name, &resbuf, &buffer, &buffer_size, 0, &result, NULL,
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AF_VAL, H_ERRNO_VAR_P))
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goto done;
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}
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#endif
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while (buffer != NULL
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&& (INTERNAL (REENTRANT_NAME) (ADD_VARIABLES, &resbuf, buffer,
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buffer_size, &result H_ERRNO_VAR)
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== ERANGE)
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#ifdef NEED_H_ERRNO
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&& h_errno_tmp == NETDB_INTERNAL
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#endif
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)
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{
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char *new_buf;
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buffer_size *= 2;
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new_buf = (char *) realloc (buffer, buffer_size);
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if (new_buf == NULL)
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{
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/* We are out of memory. Free the current buffer so that the
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process gets a chance for a normal termination. */
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free (buffer);
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__set_errno (ENOMEM);
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}
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buffer = new_buf;
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}
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if (buffer == NULL)
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result = NULL;
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#ifdef HANDLE_DIGITS_DOTS
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done:
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#endif
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/* Release lock. */
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__libc_lock_unlock (lock);
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#ifdef HANDLE_DIGITS_DOTS
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__resolv_context_put (res_ctx);
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#endif
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#ifdef NEED_H_ERRNO
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if (h_errno_tmp != 0)
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__set_h_errno (h_errno_tmp);
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#endif
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return result;
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}
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nss_interface_function (FUNCTION_NAME)
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