nscd/nscd_getgr_r.c

   1 /* Copyright (C) 1998, 1999, 2000, 2002, 2003, 2004
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Thorsten Kukuk <kukuk@uni-paderborn.de>, 1998.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <alloca.h>
  22 #include <assert.h>
  23 #include <errno.h>
  24 #include <grp.h>
  25 #include <stdint.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30 #include <sys/mman.h>
  31 #include <sys/socket.h>
  32 #include <sys/uio.h>
  33 #include <sys/un.h>
  34 #include <not-cancel.h>
  35 #include <stdio-common/_itoa.h>
  36
  37 #include "nscd-client.h"
  38 #include "nscd_proto.h"
  39
  40 int __nss_not_use_nscd_group;
  41
  42 static int nscd_getgr_r (const char *key, size_t keylen, request_type type,
  43                          struct group *resultbuf, char *buffer,
  44                          size_t buflen, struct group **result)
  45      internal_function;
  46
  47
  48 int
  49 __nscd_getgrnam_r (const char *name, struct group *resultbuf, char *buffer,
  50                    size_t buflen, struct group **result)
  51 {
  52   return nscd_getgr_r (name, strlen (name) + 1, GETGRBYNAME, resultbuf,
  53                        buffer, buflen, result);
  54 }
  55
  56
  57 int
  58 __nscd_getgrgid_r (gid_t gid, struct group *resultbuf, char *buffer,
  59                    size_t buflen, struct group **result)
  60 {
  61   char buf[3 * sizeof (gid_t)];
  62   buf[sizeof (buf) - 1] = '\0';
  63   char *cp = _itoa_word (gid, buf + sizeof (buf) - 1, 10, 0);
  64
  65   return nscd_getgr_r (cp, buf + sizeof (buf) - cp, GETGRBYGID, resultbuf,
  66                        buffer, buflen, result);
  67 }
  68
  69
  70 libc_locked_map_ptr (map_handle);
  71 /* Note that we only free the structure if necessary.  The memory
  72    mapping is not removed since it is not visible to the malloc
  73    handling.  */
  74 libc_freeres_fn (gr_map_free)
  75 {
  76
  77   if (map_handle.mapped != NO_MAPPING)
  78     free (map_handle.mapped);
  79 }
  80
  81
  82 static int
  83 internal_function
  84 nscd_getgr_r (const char *key, size_t keylen, request_type type,
  85               struct group *resultbuf, char *buffer, size_t buflen,
  86               struct group **result)
  87 {
  88   int gc_cycle;
  89   const uint32_t *len = NULL;
  90   size_t lensize = 0;
  91
  92   /* If the mapping is available, try to search there instead of
  93      communicating with the nscd.  */
  94   struct mapped_database *mapped = __nscd_get_map_ref (GETFDGR, "group",
  95                                                        &map_handle, &gc_cycle);
  96  retry:;
  97   const gr_response_header *gr_resp = NULL;
  98   const char *gr_name = NULL;
  99   size_t gr_name_len = 0;
 100   int retval = -1;
 101   const char *recend = (const char *) ~UINTMAX_C (0);
 102
 103   if (mapped != NO_MAPPING)
 104     {
 105       const struct datahead *found = __nscd_cache_search (type, key, keylen,
 106                                                           mapped);
 107       if (found != NULL)
 108         {
 109           gr_resp = &found->data[0].grdata;
 110           len = (const uint32_t *) (gr_resp + 1);
 111           /* The alignment is always sufficient.  */
 112           assert (((uintptr_t) len & (__alignof__ (*len) - 1)) == 0);
 113           gr_name = ((const char *) len
 114                      + gr_resp->gr_mem_cnt * sizeof (uint32_t));
 115           gr_name_len = gr_resp->gr_name_len + gr_resp->gr_passwd_len;
 116           recend = (const char *) found->data + found->recsize;
 117         }
 118     }
 119
 120   gr_response_header gr_resp_mem;
 121   int sock = -1;
 122   if (gr_resp == NULL)
 123     {
 124       sock = __nscd_open_socket (key, keylen, type, &gr_resp_mem,
 125                                  sizeof (gr_resp_mem));
 126       if (sock == -1)
 127         {
 128           __nss_not_use_nscd_group = 1;
 129           goto out;
 130         }
 131
 132       gr_resp = &gr_resp_mem;
 133     }
 134
 135   /* No value found so far.  */
 136   *result = NULL;
 137
 138   if (__builtin_expect (gr_resp->found == -1, 0))
 139     {
 140       /* The daemon does not cache this database.  */
 141       __nss_not_use_nscd_group = 1;
 142       goto out_close;
 143     }
 144
 145   if (gr_resp->found == 1)
 146     {
 147       struct iovec vec[2];
 148       char *p = buffer;
 149       size_t total_len;
 150       uintptr_t align;
 151       nscd_ssize_t cnt;
 152
 153       /* Now allocate the buffer the array for the group members.  We must
 154          align the pointer.  */
 155       align = ((__alignof__ (char *) - (p - ((char *) 0)))
 156                & (__alignof__ (char *) - 1));
 157       total_len = (align + (1 + gr_resp->gr_mem_cnt) * sizeof (char *)
 158                    + gr_resp->gr_name_len + gr_resp->gr_passwd_len);
 159       if (__builtin_expect (buflen < total_len, 0))
 160         {
 161         no_room:
 162           __set_errno (ERANGE);
 163           retval = ERANGE;
 164           goto out_close;
 165         }
 166       buflen -= total_len;
 167
 168       p += align;
 169       resultbuf->gr_mem = (char **) p;
 170       p += (1 + gr_resp->gr_mem_cnt) * sizeof (char *);
 171
 172       /* Set pointers for strings.  */
 173       resultbuf->gr_name = p;
 174       p += gr_resp->gr_name_len;
 175       resultbuf->gr_passwd = p;
 176       p += gr_resp->gr_passwd_len;
 177
 178       /* Fill in what we know now.  */
 179       resultbuf->gr_gid = gr_resp->gr_gid;
 180
 181       /* Read the length information, group name, and password.  */
 182       if (gr_name == NULL)
 183         {
 184           /* Allocate array to store lengths.  */
 185           if (lensize == 0)
 186             {
 187               lensize = gr_resp->gr_mem_cnt * sizeof (uint32_t);
 188               len = (uint32_t *) alloca (lensize);
 189             }
 190           else if (gr_resp->gr_mem_cnt * sizeof (uint32_t) > lensize)
 191             len = extend_alloca (len, lensize,
 192                                  gr_resp->gr_mem_cnt * sizeof (uint32_t));
 193
 194           vec[0].iov_base = (void *) len;
 195           vec[0].iov_len = gr_resp->gr_mem_cnt * sizeof (uint32_t);
 196           vec[1].iov_base = resultbuf->gr_name;
 197           vec[1].iov_len = gr_resp->gr_name_len + gr_resp->gr_passwd_len;
 198           total_len = vec[0].iov_len + vec[1].iov_len;
 199
 200           /* Get this data.  */
 201           size_t n = TEMP_FAILURE_RETRY (__readv (sock, vec, 2));
 202           if (__builtin_expect (n != total_len, 0))
 203             goto out_close;
 204         }
 205       else
 206         /* We already have the data.  Just copy the group name and
 207            password.  */
 208         memcpy (resultbuf->gr_name, gr_name, gr_name_len);
 209
 210       /* Clear the terminating entry.  */
 211       resultbuf->gr_mem[gr_resp->gr_mem_cnt] = NULL;
 212
 213       /* Prepare reading the group members.  */
 214       total_len = 0;
 215       for (cnt = 0; cnt < gr_resp->gr_mem_cnt; ++cnt)
 216         {
 217           resultbuf->gr_mem[cnt] = p;
 218           total_len += len[cnt];
 219           p += len[cnt];
 220         }
 221
 222       if (__builtin_expect (gr_name + gr_name_len + total_len > recend, 0))
 223         goto out_close;
 224       if (__builtin_expect (total_len > buflen, 0))
 225         goto no_room;
 226
 227       retval = 0;
 228       if (gr_name == NULL)
 229         {
 230           size_t n = TEMP_FAILURE_RETRY (__read (sock, resultbuf->gr_mem[0],
 231                                                  total_len));
 232           if (__builtin_expect (n != total_len, 0))
 233             {
 234               /* The `errno' to some value != ERANGE.  */
 235               __set_errno (ENOENT);
 236               retval = ENOENT;
 237             }
 238           else
 239             *result = resultbuf;
 240         }
 241       else
 242         {
 243           /* Copy the group member names.  */
 244           memcpy (resultbuf->gr_mem[0], gr_name + gr_name_len, total_len);
 245
 246           *result = resultbuf;
 247         }
 248     }
 249   else
 250     {
 251       /* The `errno' to some value != ERANGE.  */
 252       __set_errno (ENOENT);
 253       /* Even though we have not found anything, the result is zero.  */
 254       retval = 0;
 255     }
 256
 257  out_close:
 258   if (sock != -1)
 259     close_not_cancel_no_status (sock);
 260  out:
 261   if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0 && retval != -1)
 262     {
 263       /* When we come here this means there has been a GC cycle while we
 264          were looking for the data.  This means the data might have been
 265          inconsistent.  Retry if possible.  */
 266       if ((gc_cycle & 1) != 0)
 267         {
 268           /* nscd is just running gc now.  Disable using the mapping.  */
 269           __nscd_unmap (mapped);
 270           mapped = NO_MAPPING;
 271         }
 272
 273       goto retry;
 274     }
 275
 276   return retval;
 277 }