107 lines
3.5 KiB
C
107 lines
3.5 KiB
C
/* Global list of NSS service modules.
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Copyright (c) 2020-2022 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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/* Called from __libc_freeres. */
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void __nss_module_freeres (void) attribute_hidden;
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#endif /* NSS_MODULE_H */
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