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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>
117 lines
3.5 KiB
C
117 lines
3.5 KiB
C
/* NSS actions, elements in a nsswitch.conf configuration line.
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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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#include <nsswitch.h>
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#include <string.h>
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#include <libc-lock.h>
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/* Maintain a global list of NSS action lists. Since most databases
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use the same list of actions, this list is usually short.
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Deduplication in __nss_action_allocate ensures that the list does
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not grow without bounds. */
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struct nss_action_list_wrapper
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{
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/* The next element of the list. */
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struct nss_action_list_wrapper *next;
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/* Number of elements in the list (excluding the terminator). */
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size_t count;
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/* NULL-terminated list of actions. */
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struct nss_action actions[];
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};
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/* Toplevel list of allocated NSS action lists. */
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static struct nss_action_list_wrapper *nss_actions;
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/* Lock covers the nss_actions list. */
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__libc_lock_define (static, nss_actions_lock);
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/* Returns true if the actions are equal (same module, same actions
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array). */
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static bool
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actions_equal (const struct nss_action *a, const struct nss_action *b)
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{
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return a->module == b->module && a->action_bits == b->action_bits;
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}
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/* Returns true if COUNT actions at A and B are equal (according to
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actions_equal above). Caller must ensure that either A or B have at
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least COUNT actions. */
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static bool
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action_lists_equal (const struct nss_action *a, const struct nss_action *b,
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size_t count)
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{
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for (size_t i = 0; i < count; ++i)
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if (!actions_equal (a + i, b + i))
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return false;
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return true;
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}
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/* Returns a pre-allocated action list for COUNT actions at ACTIONS,
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or NULL if no such list exists. */
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static nss_action_list
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find_allocated (struct nss_action *actions, size_t count)
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{
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for (struct nss_action_list_wrapper *p = nss_actions; p != NULL; p = p->next)
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if (p->count == count && action_lists_equal (p->actions, actions, count))
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return p->actions;
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return NULL;
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}
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nss_action_list
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__nss_action_allocate (struct nss_action *actions, size_t count)
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{
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nss_action_list result = NULL;
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__libc_lock_lock (nss_actions_lock);
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result = find_allocated (actions, count);
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if (result == NULL)
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{
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struct nss_action_list_wrapper *wrapper
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= malloc (sizeof (*wrapper) + sizeof (*actions) * count);
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if (wrapper != NULL)
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{
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wrapper->next = nss_actions;
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wrapper->count = count;
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memcpy (wrapper->actions, actions, sizeof (*actions) * count);
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nss_actions = wrapper;
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result = wrapper->actions;
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}
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}
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__libc_lock_unlock (nss_actions_lock);
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return result;
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}
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void
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__nss_action_freeres (void)
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{
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struct nss_action_list_wrapper *current = nss_actions;
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while (current != NULL)
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{
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struct nss_action_list_wrapper *next = current->next;
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free (current);
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current = next;
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}
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nss_actions = NULL;
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}
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