path: root/nss/nss_compat/compat-grp.c

/* Copyright (C) 1996-2025 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 <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <nss.h>
#include <nsswitch.h>
#include <stdio_ext.h>
#include <string.h>
#include <libc-lock.h>
#include <kernel-features.h>
#include <nss_files.h>

NSS_DECLARE_MODULE_FUNCTIONS (compat)

static nss_action_list ni;
static enum nss_status (*setgrent_impl) (int stayopen);
static enum nss_status (*getgrnam_r_impl) (const char *name,
					   struct group * grp, char *buffer,
					   size_t buflen, int *errnop);
static enum nss_status (*getgrgid_r_impl) (gid_t gid, struct group * grp,
					   char *buffer, size_t buflen,
					   int *errnop);
static enum nss_status (*getgrent_r_impl) (struct group * grp, char *buffer,
					   size_t buflen, int *errnop);
static enum nss_status (*endgrent_impl) (void);

/* Get the declaration of the parser function.  */
#define ENTNAME grent
#define STRUCTURE group
#define EXTERN_PARSER
#include <nss/nss_files/files-parse.c>

/* Structure for remembering -group members ... */
#define BLACKLIST_INITIAL_SIZE 512
#define BLACKLIST_INCREMENT 256
struct blacklist_t
{
  char *data;
  int current;
  int size;
};

struct ent_t
{
  bool files;
  enum nss_status setent_status;
  FILE *stream;
  struct blacklist_t blacklist;
};
typedef struct ent_t ent_t;

static ent_t ext_ent = { true, NSS_STATUS_SUCCESS, NULL, { NULL, 0, 0 }};

/* Protect global state against multiple changers.  */
__libc_lock_define_initialized (static, lock)

/* Prototypes for local functions.  */
static void blacklist_store_name (const char *, ent_t *);
static bool in_blacklist (const char *, int, ent_t *);

/* Initialize the NSS interface/functions. The calling function must
   hold the lock.  */
static void
init_nss_interface (void)
{
  if (__nss_database_get (nss_database_group_compat, &ni))
    {
      setgrent_impl = __nss_lookup_function (ni, "setgrent");
      getgrnam_r_impl = __nss_lookup_function (ni, "getgrnam_r");
      getgrgid_r_impl = __nss_lookup_function (ni, "getgrgid_r");
      getgrent_r_impl = __nss_lookup_function (ni, "getgrent_r");
      endgrent_impl = __nss_lookup_function (ni, "endgrent");
    }
}

static enum nss_status
internal_setgrent (ent_t *ent, int stayopen, int needent)
{
  enum nss_status