pwd/pwdread.c

   1 /* Copyright (C) 1991, 1992, 1995 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <ansidecl.h>
  20 #include <errno.h>
  21 #include <limits.h>
  22 #include <stddef.h>
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <pwd.h>
  27 #include <sys/types.h>
  28
  29
  30 /* This is the function that all the others are based on.
  31    The format of the password file is known only here.  */
  32
  33 /* Structure containing info kept by each __pwdread caller.  */
  34 typedef struct
  35   {
  36     char *buf;
  37     size_t buflen;
  38     struct passwd p;
  39   } pwdread_info;
  40
  41
  42 /* Return a chunk of memory containing a pre-initialized `pwdread_info'.  */
  43 PTR
  44 DEFUN_VOID(__pwdalloc)
  45 {
  46   pwdread_info *info = (PTR) malloc (sizeof(pwdread_info));
  47   if (info == NULL)
  48     return NULL;
  49   info->buf = NULL;
  50   info->buflen = 0;
  51   return info;
  52 }
  53
  54 /* Read a password entry from STREAM, filling in P.  */
  55 struct passwd *
  56 DEFUN(__pwdread, (stream, p), FILE *stream AND PTR CONST p)
  57 {
  58   register pwdread_info *CONST info = (pwdread_info *) p;
  59   char *start, *end;
  60
  61   /* Idiocy checks.  */
  62   if (stream == NULL)
  63     {
  64       errno = EINVAL;
  65       return NULL;
  66     }
  67
  68   do
  69     if (__getline (&info->buf, &info->buflen, stream) == -1)
  70       return NULL;
  71   while (info->buf[0] == '#');
  72
  73   start = info->buf;
  74   end = strchr (start, ':');
  75   if (end == NULL)
  76     return NULL;
  77   *end = '\0';
  78   info->p.pw_name = start;
  79
  80   start = end + 1;
  81   end = strchr (start, ':');
  82   if (end == NULL)
  83     return NULL;
  84   *end = '\0';
  85   info->p.pw_passwd = start;
  86
  87   info->p.pw_uid = (uid_t) strtol (end + 1, &end, 10);
  88   if (*end != ':')
  89     return NULL;
  90   info->p.pw_gid = (gid_t) strtol (end + 1, &end, 10);
  91   if (*end != ':')
  92     return NULL;
  93
  94   start = end + 1;
  95   end = strchr (start, ':');
  96   if (end == NULL)
  97     return NULL;
  98   *end = '\0';
  99   info->p.pw_gecos = start;
 100
 101   start = end + 1;
 102   end = strchr (start, ':');
 103   if (end == NULL)
 104     return NULL;
 105   *end = '\0';
 106   info->p.pw_dir = start;
 107
 108   start = end + 1;
 109   end = strchr (start, '\n');
 110   if (end == NULL)
 111     return NULL;
 112   *end = '\0';
 113   info->p.pw_shell = start;
 114
 115   return &info->p;
 116 }
 117
 118
 119 struct passwd *
 120 __pwdscan (void **info, int (*selector) (struct passwd *))
 121 {
 122   FILE *stream;
 123   struct passwd *p;
 124
 125   if (*info == NULL)
 126     {
 127       *info = __pwdalloc ();
 128       if (info == NULL)
 129         return NULL;
 130     }
 131
 132   stream = __pwdopen ();
 133   if (stream == NULL)
 134     return NULL;
 135
 136   p = NULL;
 137   while (! feof (stream))
 138     {
 139       p = __pwdread (stream, *info);
 140       if (p && (*selector) (p))
 141         break;
 142       p = NULL;
 143     }
 144
 145   (void) fclose (stream);
 146   return p;
 147 }