grp/putgrent.c

   1 /* Copyright (C) 1991-2022 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    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <nss.h>
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include <grp.h>
  23
  24 #define flockfile(s) _IO_flockfile (s)
  25 #define funlockfile(s) _IO_funlockfile (s)
  26
  27 #define _S(x)   x ? x : ""
  28
  29 /* Write an entry to the given stream.
  30    This must know the format of the group file.  */
  31 int
  32 putgrent (const struct group *gr, FILE *stream)
  33 {
  34   int retval;
  35
  36   if (__glibc_unlikely (gr == NULL) || __glibc_unlikely (stream == NULL)
  37       || gr->gr_name == NULL || !__nss_valid_field (gr->gr_name)
  38       || !__nss_valid_field (gr->gr_passwd)
  39       || !__nss_valid_list_field (gr->gr_mem))
  40     {
  41       __set_errno (EINVAL);
  42       return -1;
  43     }
  44
  45   flockfile (stream);
  46
  47   if (gr->gr_name[0] == '+' || gr->gr_name[0] == '-')
  48     retval = fprintf (stream, "%s:%s::",
  49                       gr->gr_name, _S (gr->gr_passwd));
  50   else
  51     retval = fprintf (stream, "%s:%s:%lu:",
  52                       gr->gr_name, _S (gr->gr_passwd),
  53                       (unsigned long int) gr->gr_gid);
  54   if (__builtin_expect (retval, 0) < 0)
  55     {
  56       funlockfile (stream);
  57       return -1;
  58     }
  59
  60   if (gr->gr_mem != NULL)
  61     {
  62       for (size_t i = 0; gr->gr_mem[i] != NULL; i++)
  63         if (fprintf (stream, i == 0 ? "%s" : ",%s", gr->gr_mem[i]) < 0)
  64           {
  65             /* What else can we do?  */
  66             funlockfile (stream);
  67             return -1;
  68           }
  69     }
  70
  71   retval = fputc_unlocked ('\n', stream);
  72
  73   funlockfile (stream);
  74
  75   return retval < 0 ? -1 : 0;
  76 }