nscd/nscd_getpw_r.c

   1 /* Copyright (C) 1998, 1999, 2003, 2004, 2005 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@uni-paderborn.de>, 1998.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <assert.h>
  21 #include <errno.h>
  22 #include <pwd.h>
  23 #include <stdint.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28 #include <sys/mman.h>
  29 #include <sys/socket.h>
  30 #include <sys/uio.h>
  31 #include <sys/un.h>
  32 #include <not-cancel.h>
  33 #include <stdio-common/_itoa.h>
  34
  35 #include "nscd-client.h"
  36 #include "nscd_proto.h"
  37
  38 int __nss_not_use_nscd_passwd;
  39
  40 static int nscd_getpw_r (const char *key, size_t keylen, request_type type,
  41                          struct passwd *resultbuf, char *buffer,
  42                          size_t buflen, struct passwd **result)
  43      internal_function;
  44
  45 int
  46 __nscd_getpwnam_r (const char *name, struct passwd *resultbuf, char *buffer,
  47                    size_t buflen, struct passwd **result)
  48 {
  49   if (name == NULL)
  50     return -1;
  51
  52   return nscd_getpw_r (name, strlen (name) + 1, GETPWBYNAME, resultbuf,
  53                        buffer, buflen, result);
  54 }
  55
  56 int
  57 __nscd_getpwuid_r (uid_t uid, struct passwd *resultbuf, char *buffer,
  58                    size_t buflen, struct passwd **result)
  59 {
  60   char buf[3 * sizeof (uid_t)];
  61   buf[sizeof (buf) - 1] = '\0';
  62   char *cp = _itoa_word (uid, buf + sizeof (buf) - 1, 10, 0);
  63
  64   return nscd_getpw_r (cp, buf + sizeof (buf) - cp, GETPWBYUID, resultbuf,
  65                        buffer, buflen, result);
  66 }
  67
  68
  69 libc_locked_map_ptr (static, map_handle);
  70 /* Note that we only free the structure if necessary.  The memory
  71    mapping is not removed since it is not visible to the malloc
  72    handling.  */
  73 libc_freeres_fn (pw_map_free)
  74 {
  75   if (map_handle.mapped != NO_MAPPING)
  76     {
  77       void *p = map_handle.mapped;
  78       map_handle.mapped = NO_MAPPING;
  79       free (p);
  80     }
  81 }
  82
  83
  84 static int
  85 internal_function
  86 nscd_getpw_r (const char *key, size_t keylen, request_type type,
  87               struct passwd *resultbuf, char *buffer, size_t buflen,
  88               struct passwd **result)
  89 {
  90   int gc_cycle;
  91   /* If the mapping is available, try to search there instead of
  92      communicating with the nscd.  */
  93   struct mapped_database *mapped;
  94   mapped = __nscd_get_map_ref (GETFDPW, "passwd", &map_handle, &gc_cycle);
  95
  96  retry:;
  97   const pw_response_header *pw_resp = NULL;
  98   const char *pw_name = NULL;
  99   int retval = -1;
 100   const char *recend = (const char *) ~UINTMAX_C (0);
 101
 102   if (mapped != NO_MAPPING)
 103     {
 104       const struct datahead *found = __nscd_cache_search (type, key, keylen,
 105                                                           mapped);
 106       if (found != NULL)
 107         {
 108           pw_resp = &found->data[0].pwdata;
 109           pw_name = (const char *) (pw_resp + 1);
 110           recend = (const char *) found->data + found->recsize;
 111         }
 112     }
 113
 114   pw_response_header pw_resp_mem;
 115   int sock = -1;
 116   if (pw_resp == NULL)
 117     {
 118       sock = __nscd_open_socket (key, keylen, type, &pw_resp_mem,
 119                                  sizeof (pw_resp_mem));
 120       if (sock == -1)
 121         {
 122           __nss_not_use_nscd_passwd = 1;
 123           goto out;
 124         }
 125
 126       pw_resp = &pw_resp_mem;
 127     }
 128
 129   /* No value found so far.  */
 130   *result = NULL;
 131
 132   if (__builtin_expect (pw_resp->found == -1, 0))
 133     {
 134       /* The daemon does not cache this database.  */
 135       __nss_not_use_nscd_passwd = 1;
 136       goto out_close;
 137     }
 138
 139   if (pw_resp->found == 1)
 140     {
 141       /* Set the information we already have.  */
 142       resultbuf->pw_uid = pw_resp->pw_uid;
 143       resultbuf->pw_gid = pw_resp->pw_gid;
 144
 145       char *p = buffer;
 146       /* get pw_name */
 147       resultbuf->pw_name = p;
 148       p += pw_resp->pw_name_len;
 149       /* get pw_passwd */
 150       resultbuf->pw_passwd = p;
 151       p += pw_resp->pw_passwd_len;
 152       /* get pw_gecos */
 153       resultbuf->pw_gecos = p;
 154       p += pw_resp->pw_gecos_len;
 155       /* get pw_dir */
 156       resultbuf->pw_dir = p;
 157       p += pw_resp->pw_dir_len;
 158       /* get pw_pshell */
 159       resultbuf->pw_shell = p;
 160       p += pw_resp->pw_shell_len;
 161
 162       ssize_t total = p - buffer;
 163       if (__builtin_expect (pw_name + total > recend, 0))
 164         goto out_close;
 165       if (__builtin_expect (buflen < total, 0))
 166         {
 167           __set_errno (ERANGE);
 168           retval = ERANGE;
 169           goto out_close;
 170         }
 171
 172       retval = 0;
 173       if (pw_name == NULL)
 174         {
 175           ssize_t nbytes = __readall (sock, buffer, total);
 176
 177           if (__builtin_expect (nbytes != total, 0))
 178             {
 179               /* The `errno' to some value != ERANGE.  */
 180               __set_errno (ENOENT);
 181               retval = ENOENT;
 182             }
 183           else
 184             *result = resultbuf;
 185         }
 186       else
 187         {
 188           /* Copy the various strings.  */
 189           memcpy (resultbuf->pw_name, pw_name, total);
 190
 191           /* Try to detect corrupt databases.  */
 192           if (resultbuf->pw_name[pw_resp->pw_name_len - 1] != '\0'
 193               || resultbuf->pw_passwd[pw_resp->pw_passwd_len - 1] != '\0'
 194               || resultbuf->pw_gecos[pw_resp->pw_gecos_len - 1] != '\0'
 195               || resultbuf->pw_dir[pw_resp->pw_dir_len - 1] != '\0'
 196               || resultbuf->pw_shell[pw_resp->pw_shell_len - 1] != '\0')
 197             {
 198               /* We cannot use the database.  */
 199               retval = -1;
 200               goto out_close;
 201             }
 202
 203           *result = resultbuf;
 204         }
 205     }
 206   else
 207     {
 208       /* The `errno' to some value != ERANGE.  */
 209       __set_errno (ENOENT);
 210       /* Even though we have not found anything, the result is zero.  */
 211       retval = 0;
 212     }
 213
 214  out_close:
 215   if (sock != -1)
 216     close_not_cancel_no_status (sock);
 217  out:
 218   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0 && retval != -1)
 219     {
 220       /* When we come here this means there has been a GC cycle while we
 221          were looking for the data.  This means the data might have been
 222          inconsistent.  Retry if possible.  */
 223       if ((gc_cycle & 1) != 0)
 224         {
 225           /* nscd is just running gc now.  Disable using the mapping.  */
 226           __nscd_unmap (mapped);
 227           mapped = NO_MAPPING;
 228         }
 229
 230       goto retry;
 231     }
 232
 233   return retval;
 234 }