nscd/nscd_getpw_r.c

   1 /* Copyright (C) 1998, 1999, 2003, 2004 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 (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 (gr_map_free)
  74 {
  75
  76   if (map_handle.mapped != NO_MAPPING)
  77     free (map_handle.mapped);
  78 }
  79
  80
  81 static int
  82 internal_function
  83 nscd_getpw_r (const char *key, size_t keylen, request_type type,
  84               struct passwd *resultbuf, char *buffer, size_t buflen,
  85               struct passwd **result)
  86 {
  87   int gc_cycle;
  88   /* If the mapping is available, try to search there instead of
  89      communicating with the nscd.  */
  90   struct mapped_database *mapped;
  91   mapped = __nscd_get_map_ref (GETFDPW, "passwd", &map_handle, &gc_cycle);
  92
  93  retry:;
  94   const pw_response_header *pw_resp = NULL;
  95   const char *pw_name = NULL;
  96   int retval = -1;
  97   const char *recend = (const char *) ~UINTMAX_C (0);
  98
  99   if (mapped != NO_MAPPING)
 100     {
 101       const struct datahead *found = __nscd_cache_search (type, key, keylen,
 102                                                           mapped);
 103       if (found != NULL)
 104         {
 105           pw_resp = &found->data[0].pwdata;
 106           pw_name = (const char *) (pw_resp + 1);
 107           recend = (const char *) found->data + found->recsize;
 108         }
 109     }
 110
 111   pw_response_header pw_resp_mem;
 112   int sock = -1;
 113   if (pw_resp == NULL)
 114     {
 115       sock = __nscd_open_socket (key, keylen, type, &pw_resp_mem,
 116                                  sizeof (pw_resp_mem));
 117       if (sock == -1)
 118         {
 119           __nss_not_use_nscd_passwd = 1;
 120           goto out;
 121         }
 122
 123       pw_resp = &pw_resp_mem;
 124     }
 125
 126   /* No value found so far.  */
 127   *result = NULL;
 128
 129   if (__builtin_expect (pw_resp->found == -1, 0))
 130     {
 131       /* The daemon does not cache this database.  */
 132       __nss_not_use_nscd_passwd = 1;
 133       goto out_close;
 134     }
 135
 136   if (pw_resp->found == 1)
 137     {
 138       /* Set the information we already have.  */
 139       resultbuf->pw_uid = pw_resp->pw_uid;
 140       resultbuf->pw_gid = pw_resp->pw_gid;
 141
 142       char *p = buffer;
 143       /* get pw_name */
 144       resultbuf->pw_name = p;
 145       p += pw_resp->pw_name_len;
 146       /* get pw_passwd */
 147       resultbuf->pw_passwd = p;
 148       p += pw_resp->pw_passwd_len;
 149       /* get pw_gecos */
 150       resultbuf->pw_gecos = p;
 151       p += pw_resp->pw_gecos_len;
 152       /* get pw_dir */
 153       resultbuf->pw_dir = p;
 154       p += pw_resp->pw_dir_len;
 155       /* get pw_pshell */
 156       resultbuf->pw_shell = p;
 157       p += pw_resp->pw_shell_len;
 158
 159       ssize_t total = p - buffer;
 160       if (__builtin_expect (pw_name + total > recend, 0))
 161         goto out_close;
 162       if (__builtin_expect (buflen < total, 0))
 163         {
 164           __set_errno (ERANGE);
 165           retval = ERANGE;
 166           goto out_close;
 167         }
 168
 169       retval = 0;
 170       if (pw_name == NULL)
 171         {
 172           ssize_t nbytes = TEMP_FAILURE_RETRY (__read (sock, buffer, total));
 173
 174           if (__builtin_expect (nbytes != total, 0))
 175             {
 176               /* The `errno' to some value != ERANGE.  */
 177               __set_errno (ENOENT);
 178               retval = ENOENT;
 179             }
 180           else
 181             *result = resultbuf;
 182         }
 183       else
 184         {
 185           /* Copy the various strings.  */
 186           memcpy (resultbuf->pw_name, pw_name, total);
 187
 188           *result = resultbuf;
 189         }
 190     }
 191   else
 192     {
 193       /* The `errno' to some value != ERANGE.  */
 194       __set_errno (ENOENT);
 195       /* Even though we have not found anything, the result is zero.  */
 196       retval = 0;
 197     }
 198
 199  out_close:
 200   if (sock != -1)
 201     close_not_cancel_no_status (sock);
 202  out:
 203   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0 && retval != -1)
 204     {
 205       /* When we come here this means there has been a GC cycle while we
 206          were looking for the data.  This means the data might have been
 207          inconsistent.  Retry if possible.  */
 208       if ((gc_cycle & 1) != 0)
 209         {
 210           /* nscd is just running gc now.  Disable using the mapping.  */
 211           __nscd_unmap (mapped);
 212           mapped = NO_MAPPING;
 213         }
 214
 215       free (resultbuf);
 216
 217       goto retry;
 218     }
 219
 220   return retval;
 221 }