grp/putgrent.c

   1 /* Copyright (C) 1991-2014 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 <errno.h>
  19 #include <stdio.h>
  20 #include <grp.h>
  21
  22 #define flockfile(s) _IO_flockfile (s)
  23 #define funlockfile(s) _IO_funlockfile (s)
  24
  25 #define _S(x)   x ? x : ""
  26
  27 /* Write an entry to the given stream.
  28    This must know the format of the group file.  */
  29 int
  30 putgrent (gr, stream)
  31      const struct group *gr;
  32      FILE *stream;
  33 {
  34   int retval;
  35
  36   if (__glibc_unlikely (gr == NULL) || __glibc_unlikely (stream == NULL))
  37     {
  38       __set_errno (EINVAL);
  39       return -1;
  40     }
  41
  42   flockfile (stream);
  43
  44   if (gr->gr_name[0] == '+' || gr->gr_name[0] == '-')
  45     retval = fprintf (stream, "%s:%s::",
  46                       gr->gr_name, _S (gr->gr_passwd));
  47   else
  48     retval = fprintf (stream, "%s:%s:%lu:",
  49                       gr->gr_name, _S (gr->gr_passwd),
  50                       (unsigned long int) gr->gr_gid);
  51   if (__builtin_expect (retval, 0) < 0)
  52     {
  53       funlockfile (stream);
  54       return -1;
  55     }
  56
  57   if (gr->gr_mem != NULL)
  58     {
  59       int i;
  60
  61       for (i = 0 ; gr->gr_mem[i] != NULL; i++)
  62         if (fprintf (stream, i == 0 ? "%s" : ",%s", gr->gr_mem[i]) < 0)
  63           {
  64             /* What else can we do?  */
  65             funlockfile (stream);
  66             return -1;
  67           }
  68     }
  69
  70   retval = fputc_unlocked ('\n', stream);
  71
  72   funlockfile (stream);
  73
  74   return retval < 0 ? -1 : 0;
  75 }