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