source/lib/util_pw.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    Safe versions of getpw* calls
   5
   6    Copyright (C) Andrew Bartlett 2002
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 static struct passwd *alloc_copy_passwd(const struct passwd *from)
  26 {
  27         struct passwd *ret = SMB_XMALLOC_P(struct passwd);
  28         ZERO_STRUCTP(ret);
  29         ret->pw_name = smb_xstrdup(from->pw_name);
  30         ret->pw_passwd = smb_xstrdup(from->pw_passwd);
  31         ret->pw_uid = from->pw_uid;
  32         ret->pw_gid = from->pw_gid;
  33         ret->pw_gecos = smb_xstrdup(from->pw_gecos);
  34         ret->pw_dir = smb_xstrdup(from->pw_dir);
  35         ret->pw_shell = smb_xstrdup(from->pw_shell);
  36         return ret;
  37 }
  38
  39 void passwd_free (struct passwd **buf)
  40 {
  41         if (!*buf) {
  42                 DEBUG(0, ("attempted double-free of allocated passwd\n"));
  43                 return;
  44         }
  45
  46         SAFE_FREE((*buf)->pw_name);
  47         SAFE_FREE((*buf)->pw_passwd);
  48         SAFE_FREE((*buf)->pw_gecos);
  49         SAFE_FREE((*buf)->pw_dir);
  50         SAFE_FREE((*buf)->pw_shell);
  51
  52         SAFE_FREE(*buf);
  53 }
  54
  55 #define PWNAMCACHE_SIZE 4
  56 static struct passwd *pwnam_cache[PWNAMCACHE_SIZE];
  57 static BOOL pwnam_cache_initialized = False;
  58
  59 static void init_pwnam_cache(void)
  60 {
  61         int i;
  62
  63         if (pwnam_cache_initialized)
  64                 return;
  65
  66         for (i=0; i<PWNAMCACHE_SIZE; i++)
  67                 pwnam_cache[i] = NULL;
  68
  69         pwnam_cache_initialized = True;
  70         return;
  71 }
  72
  73 struct passwd *getpwnam_alloc(const char *name)
  74 {
  75         int i;
  76
  77         struct passwd *temp;
  78
  79         init_pwnam_cache();
  80
  81         for (i=0; i<PWNAMCACHE_SIZE; i++) {
  82                 if ((pwnam_cache[i] != NULL) &&
  83                     (strcmp(name, pwnam_cache[i]->pw_name) == 0)) {
  84                         DEBUG(10, ("Got %s from pwnam_cache\n", name));
  85                         return alloc_copy_passwd(pwnam_cache[i]);
  86                 }
  87         }
  88
  89         temp = sys_getpwnam(name);
  90
  91         if (!temp) {
  92 #if 0
  93                 if (errno == ENOMEM) {
  94                         /* what now? */
  95                 }
  96 #endif
  97                 return NULL;
  98         }
  99
 100         for (i=0; i<PWNAMCACHE_SIZE; i++) {
 101                 if (pwnam_cache[i] == NULL)
 102                         break;
 103         }
 104
 105         if (i == PWNAMCACHE_SIZE)
 106                 i = rand() % PWNAMCACHE_SIZE;
 107
 108         if (pwnam_cache[i] != NULL)
 109                 passwd_free(&pwnam_cache[i]);
 110
 111         pwnam_cache[i] = alloc_copy_passwd(temp);
 112
 113         return alloc_copy_passwd(temp);
 114 }
 115
 116 struct passwd *getpwuid_alloc(uid_t uid)
 117 {
 118         struct passwd *temp;
 119
 120         temp = sys_getpwuid(uid);
 121
 122         if (!temp) {
 123 #if 0
 124                 if (errno == ENOMEM) {
 125                         /* what now? */
 126                 }
 127 #endif
 128                 return NULL;
 129         }
 130
 131         return alloc_copy_passwd(temp);
 132 }