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 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, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23
  24 struct passwd *tcopy_passwd(TALLOC_CTX *mem_ctx, const struct passwd *from)
  25 {
  26         struct passwd *ret = TALLOC_P(mem_ctx, struct passwd);
  27         if (!ret) {
  28                 return NULL;
  29         }
  30         ret->pw_name = talloc_strdup(ret, from->pw_name);
  31         ret->pw_passwd = talloc_strdup(ret, from->pw_passwd);
  32         ret->pw_uid = from->pw_uid;
  33         ret->pw_gid = from->pw_gid;
  34         ret->pw_gecos = talloc_strdup(ret, from->pw_gecos);
  35         ret->pw_dir = talloc_strdup(ret, from->pw_dir);
  36         ret->pw_shell = talloc_strdup(ret, from->pw_shell);
  37         return ret;
  38 }
  39
  40 #define PWNAMCACHE_SIZE 4
  41 static struct passwd **pwnam_cache = NULL;
  42
  43 static void init_pwnam_cache(void)
  44 {
  45         if (pwnam_cache != NULL)
  46                 return;
  47
  48         pwnam_cache = TALLOC_ZERO_ARRAY(NULL, struct passwd *,
  49                                         PWNAMCACHE_SIZE);
  50         if (pwnam_cache == NULL) {
  51                 smb_panic("Could not init pwnam_cache");
  52         }
  53
  54         return;
  55 }
  56
  57 void flush_pwnam_cache(void)
  58 {
  59         TALLOC_FREE(pwnam_cache);
  60         pwnam_cache = NULL;
  61         init_pwnam_cache();
  62 }
  63
  64 struct passwd *getpwnam_alloc(TALLOC_CTX *mem_ctx, const char *name)
  65 {
  66         int i;
  67
  68         struct passwd *temp;
  69
  70         init_pwnam_cache();
  71
  72         for (i=0; i<PWNAMCACHE_SIZE; i++) {
  73                 if ((pwnam_cache[i] != NULL) &&
  74                     (strcmp(name, pwnam_cache[i]->pw_name) == 0)) {
  75                         DEBUG(10, ("Got %s from pwnam_cache\n", name));
  76                         return tcopy_passwd(mem_ctx, pwnam_cache[i]);
  77                 }
  78         }
  79
  80         temp = sys_getpwnam(name);
  81
  82         if (!temp) {
  83 #if 0
  84                 if (errno == ENOMEM) {
  85                         /* what now? */
  86                 }
  87 #endif
  88                 return NULL;
  89         }
  90
  91         for (i=0; i<PWNAMCACHE_SIZE; i++) {
  92                 if (pwnam_cache[i] == NULL)
  93                         break;
  94         }
  95
  96         if (i == PWNAMCACHE_SIZE)
  97                 i = rand() % PWNAMCACHE_SIZE;
  98
  99         if (pwnam_cache[i] != NULL) {
 100                 /* Remove this old cache entry, from the cache.  We
 101                  * use talloc_unlink here because we want to be very
 102                  * clear which referece we are removing */
 103                 talloc_unlink(pwnam_cache, pwnam_cache[i]);
 104         }
 105
 106         pwnam_cache[i] = tcopy_passwd(pwnam_cache, temp);
 107
 108         return tcopy_passwd(mem_ctx, temp);
 109 }
 110
 111 struct passwd *getpwuid_alloc(TALLOC_CTX *mem_ctx, uid_t uid)
 112 {
 113         struct passwd *temp;
 114
 115         temp = sys_getpwuid(uid);
 116
 117         if (!temp) {
 118 #if 0
 119                 if (errno == ENOMEM) {
 120                         /* what now? */
 121                 }
 122 #endif
 123                 return NULL;
 124         }
 125
 126         return tcopy_passwd(mem_ctx, temp);
 127 }