source3/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 3 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 struct passwd *tcopy_passwd(TALLOC_CTX *mem_ctx, const struct passwd *from)
  26 {
  27         struct passwd *ret = TALLOC_P(mem_ctx, struct passwd);
  28         if (!ret) {
  29                 return NULL;
  30         }
  31         ret->pw_name = talloc_strdup(ret, from->pw_name);
  32         ret->pw_passwd = talloc_strdup(ret, from->pw_passwd);
  33         ret->pw_uid = from->pw_uid;
  34         ret->pw_gid = from->pw_gid;
  35         ret->pw_gecos = talloc_strdup(ret, from->pw_gecos);
  36         ret->pw_dir = talloc_strdup(ret, from->pw_dir);
  37         ret->pw_shell = talloc_strdup(ret, from->pw_shell);
  38         return ret;
  39 }
  40
  41 #define PWNAMCACHE_SIZE 4
  42 static struct passwd **pwnam_cache = NULL;
  43
  44 static void init_pwnam_cache(void)
  45 {
  46         if (pwnam_cache != NULL)
  47                 return;
  48
  49         pwnam_cache = TALLOC_ZERO_ARRAY(NULL, struct passwd *,
  50                                         PWNAMCACHE_SIZE);
  51         if (pwnam_cache == NULL) {
  52                 smb_panic("Could not init pwnam_cache");
  53         }
  54
  55         return;
  56 }
  57
  58 void flush_pwnam_cache(void)
  59 {
  60         TALLOC_FREE(pwnam_cache);
  61         pwnam_cache = NULL;
  62         init_pwnam_cache();
  63 }
  64
  65 struct passwd *getpwnam_alloc(TALLOC_CTX *mem_ctx, const char *name)
  66 {
  67         int i;
  68
  69         struct passwd *temp;
  70
  71         init_pwnam_cache();
  72
  73         for (i=0; i<PWNAMCACHE_SIZE; i++) {
  74                 if ((pwnam_cache[i] != NULL) &&
  75                     (strcmp(name, pwnam_cache[i]->pw_name) == 0)) {
  76                         DEBUG(10, ("Got %s from pwnam_cache\n", name));
  77                         return tcopy_passwd(mem_ctx, pwnam_cache[i]);
  78                 }
  79         }
  80
  81         temp = sys_getpwnam(name);
  82
  83         if (!temp) {
  84 #if 0
  85                 if (errno == ENOMEM) {
  86                         /* what now? */
  87                 }
  88 #endif
  89                 return NULL;
  90         }
  91
  92         for (i=0; i<PWNAMCACHE_SIZE; i++) {
  93                 if (pwnam_cache[i] == NULL)
  94                         break;
  95         }
  96
  97         if (i == PWNAMCACHE_SIZE)
  98                 i = rand() % PWNAMCACHE_SIZE;
  99
 100         if (pwnam_cache[i] != NULL) {
 101                 /* Remove this old cache entry, from the cache.  We
 102                  * use talloc_unlink here because we want to be very
 103                  * clear which referece we are removing */
 104                 talloc_unlink(pwnam_cache, pwnam_cache[i]);
 105         }
 106
 107         pwnam_cache[i] = tcopy_passwd(pwnam_cache, temp);
 108
 109         return tcopy_passwd(mem_ctx, temp);
 110 }
 111
 112 struct passwd *getpwuid_alloc(TALLOC_CTX *mem_ctx, uid_t uid)
 113 {
 114         struct passwd *temp;
 115
 116         temp = sys_getpwuid(uid);
 117
 118         if (!temp) {
 119 #if 0
 120                 if (errno == ENOMEM) {
 121                         /* what now? */
 122                 }
 123 #endif
 124                 return NULL;
 125         }
 126
 127         return tcopy_passwd(mem_ctx, temp);
 128 }