pwd/putpwent.c

   1 /* Copyright (C) 1991-2020 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 <stdio.h>
  20 #include <pwd.h>
  21 #include <nss.h>
  22
  23 #define _S(x)   x ?: ""
  24
  25 /* Write an entry to the given stream.  This must know the format of
  26    the password file.  If the input contains invalid characters,
  27    return EINVAL, or replace them with spaces (if they are contained
  28    in the GECOS field).  */
  29 int
  30 putpwent (const struct passwd *p, FILE *stream)
  31 {
  32   if (p == NULL || stream == NULL
  33       || p->pw_name == NULL || !__nss_valid_field (p->pw_name)
  34       || !__nss_valid_field (p->pw_passwd)
  35       || !__nss_valid_field (p->pw_dir)
  36       || !__nss_valid_field (p->pw_shell))
  37     {
  38       __set_errno (EINVAL);
  39       return -1;
  40     }
  41
  42   int ret;
  43   char *gecos_alloc;
  44   const char *gecos = __nss_rewrite_field (p->pw_gecos, &gecos_alloc);
  45
  46   if (gecos == NULL)
  47     return -1;
  48
  49   if (p->pw_name[0] == '+' || p->pw_name[0] == '-')
  50       ret = fprintf (stream, "%s:%s:::%s:%s:%s\n",
  51                      p->pw_name, _S (p->pw_passwd),
  52                      gecos, _S (p->pw_dir), _S (p->pw_shell));
  53   else
  54       ret = fprintf (stream, "%s:%s:%lu:%lu:%s:%s:%s\n",
  55                      p->pw_name, _S (p->pw_passwd),
  56                      (unsigned long int) p->pw_uid,
  57                      (unsigned long int) p->pw_gid,
  58                      gecos, _S (p->pw_dir), _S (p->pw_shell));
  59
  60   free (gecos_alloc);
  61   if (ret >= 0)
  62     ret = 0;
  63   return ret;
  64 }