grp/fgetgrent_r.c

   1 /* Copyright (C) 1991-2019 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <ctype.h>
  19 #include <errno.h>
  20 #include <grp.h>
  21 #include <stdio.h>
  22
  23 #include <libio/iolibio.h>
  24 #define flockfile(s) _IO_flockfile (s)
  25 #define funlockfile(s) _IO_funlockfile (s)
  26
  27 /* Define a line parsing function using the common code
  28    used in the nss_files module.  */
  29
  30 #define STRUCTURE       group
  31 #define ENTNAME         grent
  32 struct grent_data {};
  33
  34 #define TRAILING_LIST_MEMBER            gr_mem
  35 #define TRAILING_LIST_SEPARATOR_P(c)    ((c) == ',')
  36 #include <nss/nss_files/files-parse.c>
  37 LINE_PARSER
  38 (,
  39  STRING_FIELD (result->gr_name, ISCOLON, 0);
  40  if (line[0] == '\0'
  41      && (result->gr_name[0] == '+' || result->gr_name[0] == '-'))
  42    {
  43      result->gr_passwd = NULL;
  44      result->gr_gid = 0;
  45    }
  46  else
  47    {
  48      STRING_FIELD (result->gr_passwd, ISCOLON, 0);
  49      if (result->gr_name[0] == '+' || result->gr_name[0] == '-')
  50        INT_FIELD_MAYBE_NULL (result->gr_gid, ISCOLON, 0, 10, , 0)
  51      else
  52        INT_FIELD (result->gr_gid, ISCOLON, 0, 10,)
  53    }
  54  )
  55
  56
  57 /* Read one entry from the given stream.  */
  58 int
  59 __fgetgrent_r (FILE *stream, struct group *resbuf, char *buffer, size_t buflen,
  60                struct group **result)
  61 {
  62   char *p;
  63   int parse_result;
  64
  65   flockfile (stream);
  66   do
  67     {
  68       buffer[buflen - 1] = '\xff';
  69       p = fgets_unlocked (buffer, buflen, stream);
  70       if (__builtin_expect (p == NULL, 0) && feof_unlocked (stream))
  71         {
  72           funlockfile (stream);
  73           *result = NULL;
  74           __set_errno (ENOENT);
  75           return errno;
  76         }
  77       if (__builtin_expect (p == NULL, 0) || buffer[buflen - 1] != '\xff')
  78         {
  79           funlockfile (stream);
  80           *result = NULL;
  81           __set_errno (ERANGE);
  82           return errno;
  83         }
  84
  85       /* Skip leading blanks.  */
  86       while (isspace (*p))
  87         ++p;
  88     } while (*p == '\0' || *p == '#'    /* Ignore empty and comment lines.  */
  89              /* Parse the line.  If it is invalid, loop to
  90                 get the next line of the file to parse.  */
  91              || ! (parse_result = parse_line (p, resbuf,
  92                                               (void *) buffer, buflen,
  93                                               &errno)));
  94
  95   funlockfile (stream);
  96
  97   if (__builtin_expect (parse_result, 0) == -1)
  98     {
  99       /* The parser ran out of space.  */
 100       *result = NULL;
 101       return errno;
 102     }
 103
 104   *result = resbuf;
 105   return 0;
 106 }
 107 weak_alias (__fgetgrent_r, fgetgrent_r)