nss/nss_db/db-open.c

   1 /* Common database routines for nss_db.
   2    Copyright (C) 2000, 2011 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <dlfcn.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26 #include <sys/mman.h>
  27 #include <not-cancel.h>
  28
  29 #include <kernel-features.h>
  30 #include "nss_db.h"
  31
  32 /* Open the database stored in FILE.  If succesful, store either a
  33    pointer to the mapped file or a file handle for the file in H and
  34    return NSS_STATUS_SUCCESS.  On failure, return the appropriate
  35    lookup status.  */
  36 enum nss_status
  37 internal_setent (const char *file, struct nss_db_map *mapping)
  38 {
  39   enum nss_status status = NSS_STATUS_UNAVAIL;
  40
  41   int mode = O_RDONLY | O_LARGEFILE;
  42 #ifdef O_CLOEXEC
  43   mode |= O_CLOEXEC;
  44 #endif
  45   int fd = open_not_cancel_2 (file, mode);
  46   if (fd != -1)
  47     {
  48       struct nss_db_header header;
  49
  50       if (read (fd, &header, sizeof (header)) == sizeof (header))
  51         {
  52           mapping->header = mmap (NULL, header.allocate, PROT_READ,
  53                                   MAP_PRIVATE, fd, 0);
  54           mapping->len = header.allocate;
  55           if (mapping->header != MAP_FAILED)
  56             status = NSS_STATUS_SUCCESS;
  57           else if (errno == ENOMEM)
  58             status = NSS_STATUS_TRYAGAIN;
  59         }
  60
  61       close_not_cancel_no_status (fd);
  62     }
  63
  64   return status;
  65 }
  66
  67
  68 /* Close the database.  */
  69 void
  70 internal_endent (struct nss_db_map *mapping)
  71 {
  72   munmap (mapping->header, mapping->len);
  73 }