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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>
104 lines
3.4 KiB
C
104 lines
3.4 KiB
C
/* Global list of NSS service modules.
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Copyright (c) 2020-2023 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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#ifndef _NSS_MODULE_H
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#define _NSS_MODULE_H
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#include <nss.h>
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#include <stdbool.h>
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/* See nss_database.h for a summary of how this relates. */
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/* Typed function pointers for all functions that can be defined by a
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service module. */
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struct nss_module_functions
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{
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#undef DEFINE_NSS_FUNCTION
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#define DEFINE_NSS_FUNCTION(f) nss_##f *f;
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#include "function.def"
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};
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/* Number of elements of the nss_module_functions_untyped array. */
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enum
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{
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nss_module_functions_count = (sizeof (struct nss_module_functions)
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/ sizeof (void *))
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};
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/* Untyped version of struct nss_module_functions, for consistent
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processing purposes. */
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typedef void *nss_module_functions_untyped[nss_module_functions_count];
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/* Locate the nss_files functions, as if by dlopen/dlsym. */
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void __nss_files_functions (nss_module_functions_untyped pointers)
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attribute_hidden;
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/* Initialization state of a NSS module. */
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enum nss_module_state
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{
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nss_module_uninitialized,
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nss_module_loaded,
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nss_module_failed,
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};
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/* A NSS service module (potentially unloaded). Client code should
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use the functions below. */
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struct nss_module
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{
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/* Actual type is enum nss_module_state. Use int due to atomic
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access. Used in a double-checked locking idiom. */
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int state;
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/* The function pointers in the module. */
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union
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{
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struct nss_module_functions typed;
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nss_module_functions_untyped untyped;
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} functions;
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/* Only used for __libc_freeres unloading. */
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void *handle;
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/* The next module in the list. */
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struct nss_module *next;
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/* The name of the module (as it appears in /etc/nsswitch.conf). */
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char name[];
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};
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/* Allocates the NSS module NAME (of NAME_LENGTH bytes) and places it
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into the global list. If it already exists in the list, return the
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pre-existing module. This does not actually load the module.
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Returns NULL on memory allocation failure. */
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struct nss_module *__nss_module_allocate (const char *name,
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size_t name_length) attribute_hidden;
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/* Ensures that MODULE is in a loaded or failed state. */
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bool __nss_module_load (struct nss_module *module) attribute_hidden;
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/* Ensures that MODULE is loaded and returns a pointer to the function
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NAME defined in it. Returns NULL if MODULE could not be loaded, or
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if the function NAME is not defined in the module. */
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void *__nss_module_get_function (struct nss_module *module, const char *name)
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attribute_hidden;
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/* Block attempts to dlopen any module we haven't already opened. */
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void __nss_module_disable_loading (void);
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#endif /* NSS_MODULE_H */
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