mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-27 07:20:11 +00:00
117 lines
3.5 KiB
C
117 lines
3.5 KiB
C
/* NSS actions, elements in a nsswitch.conf configuration line.
|
|
Copyright (c) 2020-2024 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <nsswitch.h>
|
|
|
|
#include <string.h>
|
|
#include <libc-lock.h>
|
|
|
|
/* Maintain a global list of NSS action lists. Since most databases
|
|
use the same list of actions, this list is usually short.
|
|
Deduplication in __nss_action_allocate ensures that the list does
|
|
not grow without bounds. */
|
|
|
|
struct nss_action_list_wrapper
|
|
{
|
|
/* The next element of the list. */
|
|
struct nss_action_list_wrapper *next;
|
|
|
|
/* Number of elements in the list (excluding the terminator). */
|
|
size_t count;
|
|
|
|
/* NULL-terminated list of actions. */
|
|
struct nss_action actions[];
|
|
};
|
|
|
|
/* Toplevel list of allocated NSS action lists. */
|
|
static struct nss_action_list_wrapper *nss_actions;
|
|
|
|
/* Lock covers the nss_actions list. */
|
|
__libc_lock_define (static, nss_actions_lock);
|
|
|
|
/* Returns true if the actions are equal (same module, same actions
|
|
array). */
|
|
static bool
|
|
actions_equal (const struct nss_action *a, const struct nss_action *b)
|
|
{
|
|
return a->module == b->module && a->action_bits == b->action_bits;
|
|
}
|
|
|
|
|
|
/* Returns true if COUNT actions at A and B are equal (according to
|
|
actions_equal above). Caller must ensure that either A or B have at
|
|
least COUNT actions. */
|
|
static bool
|
|
action_lists_equal (const struct nss_action *a, const struct nss_action *b,
|
|
size_t count)
|
|
{
|
|
for (size_t i = 0; i < count; ++i)
|
|
if (!actions_equal (a + i, b + i))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/* Returns a pre-allocated action list for COUNT actions at ACTIONS,
|
|
or NULL if no such list exists. */
|
|
static nss_action_list
|
|
find_allocated (struct nss_action *actions, size_t count)
|
|
{
|
|
for (struct nss_action_list_wrapper *p = nss_actions; p != NULL; p = p->next)
|
|
if (p->count == count && action_lists_equal (p->actions, actions, count))
|
|
return p->actions;
|
|
return NULL;
|
|
}
|
|
|
|
nss_action_list
|
|
__nss_action_allocate (struct nss_action *actions, size_t count)
|
|
{
|
|
nss_action_list result = NULL;
|
|
__libc_lock_lock (nss_actions_lock);
|
|
|
|
result = find_allocated (actions, count);
|
|
if (result == NULL)
|
|
{
|
|
struct nss_action_list_wrapper *wrapper
|
|
= malloc (sizeof (*wrapper) + sizeof (*actions) * count);
|
|
if (wrapper != NULL)
|
|
{
|
|
wrapper->next = nss_actions;
|
|
wrapper->count = count;
|
|
memcpy (wrapper->actions, actions, sizeof (*actions) * count);
|
|
nss_actions = wrapper;
|
|
result = wrapper->actions;
|
|
}
|
|
}
|
|
|
|
__libc_lock_unlock (nss_actions_lock);
|
|
return result;
|
|
}
|
|
|
|
void
|
|
__nss_action_freeres (void)
|
|
{
|
|
struct nss_action_list_wrapper *current = nss_actions;
|
|
while (current != NULL)
|
|
{
|
|
struct nss_action_list_wrapper *next = current->next;
|
|
free (current);
|
|
current = next;
|
|
}
|
|
nss_actions = NULL;
|
|
}
|