pwd/getpw.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 <alloca.h>
  19 #include <errno.h>
  20 #include <stdio.h>
  21 #include <unistd.h>
  22 #include <pwd.h>
  23
  24
  25 /* Re-construct the password-file line for the given uid
  26    in the given buffer.  This knows the format that the caller
  27    will expect, but this need not be the format of the password file.  */
  28
  29 int __getpw (__uid_t uid, char *buf);
  30
  31 int
  32 __getpw (__uid_t uid, char *buf)
  33 {
  34   size_t buflen;
  35   char *tmpbuf;
  36   struct passwd resbuf, *p;
  37
  38   if (buf == NULL)
  39     {
  40       __set_errno (EINVAL);
  41       return -1;
  42     }
  43
  44   buflen = __sysconf (_SC_GETPW_R_SIZE_MAX);
  45   tmpbuf = alloca (buflen);
  46
  47   if (__getpwuid_r (uid, &resbuf, tmpbuf, buflen, &p) != 0)
  48     return -1;
  49
  50   if (p == NULL)
  51     return -1;
  52
  53   if (sprintf (buf, "%s:%s:%lu:%lu:%s:%s:%s", p->pw_name, p->pw_passwd,
  54                (unsigned long int) p->pw_uid, (unsigned long int) p->pw_gid,
  55                p->pw_gecos, p->pw_dir, p->pw_shell) < 0)
  56     return -1;
  57
  58   return 0;
  59 }
  60 weak_alias (__getpw, getpw)
  61
  62 link_warning (getpw, "the `getpw' function is dangerous and should not be used.")