nss/tst-nss-files-hosts-getent.c

   1 /* Enumerate /etc/hosts with a long line (bug 18991).
   2    Copyright (C) 2018-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19
  20 #include <dlfcn.h>
  21 #include <errno.h>
  22 #include <gnu/lib-names.h>
  23 #include <netdb.h>
  24 #include <nss.h>
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <support/check.h>
  28 #include <support/check_nss.h>
  29 #include <support/namespace.h>
  30 #include <support/support.h>
  31 #include <support/test-driver.h>
  32 #include <support/xmemstream.h>
  33 #include <support/xstdio.h>
  34 #include <support/xunistd.h>
  35
  36 struct support_chroot *chroot_env;
  37
  38 /* Number of alias names in the long line.  This is varied to catch
  39    different cases where the ERANGE handling can go wrong (line buffer
  40    length, alias buffer).  */
  41 static int name_count;
  42
  43 /* Write /etc/hosts, from outside of the chroot.  */
  44 static void
  45 write_hosts (void)
  46 {
  47   FILE *fp = xfopen (chroot_env->path_hosts, "w");
  48   fputs ("127.0.0.1   localhost localhost.localdomain\n", fp);
  49   fputs ("192.0.2.2 host2.example.com\n", fp);
  50   fputs ("192.0.2.1", fp);
  51   for (int i = 0; i < name_count; ++i)
  52     fprintf (fp, " host%d.example.com", i);
  53   fputs ("\n192.0.2.80 www.example.com\n"
  54          "192.0.2.5 host5.example.com\n"
  55          "192.0.2.81 www1.example.com\n", fp);
  56   xfclose (fp);
  57 }
  58
  59 const char *host1_expected =
  60   "name: localhost\n"
  61   "alias: localhost.localdomain\n"
  62   "address: 127.0.0.1\n";
  63 const char *host2_expected =
  64   "name: host2.example.com\n"
  65   "address: 192.0.2.2\n";
  66 const char *host4_expected =
  67   "name: www.example.com\n"
  68   "address: 192.0.2.80\n";
  69 const char *host5_expected =
  70   "name: host5.example.com\n"
  71   "address: 192.0.2.5\n";
  72 const char *host6_expected =
  73   "name: www1.example.com\n"
  74   "address: 192.0.2.81\n";
  75
  76 static void
  77 prepare (int argc, char **argv)
  78 {
  79   chroot_env = support_chroot_create
  80     ((struct support_chroot_configuration)
  81      {
  82        .resolv_conf = "",
  83        .hosts = "",             /* Filled in by write_hosts.  */
  84        .host_conf = "multi on\n",
  85      });
  86 }
  87
  88 /* If -1, no sethostent call.  Otherwise, pass do_stayopen as the
  89    sethostent argument.  */
  90 static int do_stayopen;
  91
  92 /* If non-zero, perform an endostent call.  */
  93 static int do_endent;
  94
  95 static void
  96 subprocess_getent (void *closure)
  97 {
  98   xchroot (chroot_env->path_chroot);
  99
 100   errno = 0;
 101   if (do_stayopen >= 0)
 102     sethostent (do_stayopen);
 103   TEST_VERIFY (errno == 0);
 104
 105   int i = 0;
 106   while (true)
 107     {
 108       struct xmemstream expected;
 109       xopen_memstream (&expected);
 110       switch (++i)
 111         {
 112         case 1:
 113           fputs (host1_expected, expected.out);
 114           break;
 115         case 2:
 116           fputs (host2_expected, expected.out);
 117           break;
 118         case 3:
 119           fputs ("name: host0.example.com\n", expected.out);
 120           for (int j = 1; j < name_count; ++j)
 121             fprintf (expected.out, "alias: host%d.example.com\n", j);
 122           fputs ("address: 192.0.2.1\n", expected.out);
 123           break;
 124         case 4:
 125           fputs (host4_expected, expected.out);
 126           break;
 127         case 5:
 128           fputs (host5_expected, expected.out);
 129           break;
 130         case 6:
 131           fputs (host6_expected, expected.out);
 132           break;
 133         default:
 134           fprintf (expected.out, "*** unexpected host %d ***\n", i);
 135           break;
 136         }
 137       xfclose_memstream (&expected);
 138       char *context = xasprintf ("do_stayopen=%d host=%d", do_stayopen, i);
 139
 140       errno = 0;
 141       struct hostent *e = gethostent ();
 142       if (e == NULL)
 143         {
 144           TEST_VERIFY (errno == 0);
 145           break;
 146         }
 147       check_hostent (context, e, expected.buffer);
 148       free (context);
 149       free (expected.buffer);
 150     }
 151
 152   errno = 0;
 153   if (do_endent)
 154     endhostent ();
 155   TEST_VERIFY (errno == 0);
 156
 157   /* Exercise process termination.   */
 158   exit (0);
 159 }
 160
 161 /* getaddrinfo test.  To be run from a subprocess.  */
 162 static void
 163 test_gai (int family)
 164 {
 165   struct addrinfo hints =
 166     {
 167       .ai_family = family,
 168       .ai_protocol = IPPROTO_TCP,
 169       .ai_socktype = SOCK_STREAM,
 170     };
 171
 172   struct addrinfo *ai;
 173   int ret = getaddrinfo ("host2.example.com", "80", &hints, &ai);
 174   check_addrinfo ("host2.example.com", ai, ret,
 175                   "address: STREAM/TCP 192.0.2.2 80\n"
 176                   "address: STREAM/TCP 192.0.2.1 80\n");
 177
 178   ret = getaddrinfo ("host5.example.com", "80", &hints, &ai);
 179   check_addrinfo ("host5.example.com", ai, ret,
 180                   "address: STREAM/TCP 192.0.2.1 80\n"
 181                   "address: STREAM/TCP 192.0.2.5 80\n");
 182
 183   ret = getaddrinfo ("www.example.com", "80", &hints, &ai);
 184   check_addrinfo ("www.example.com", ai, ret,
 185                   "address: STREAM/TCP 192.0.2.80 80\n");
 186
 187   ret = getaddrinfo ("www1.example.com", "80", &hints, &ai);
 188   check_addrinfo ("www1.example.com", ai, ret,
 189                   "address: STREAM/TCP 192.0.2.81 80\n");
 190 }
 191
 192 /* Subprocess routine for gethostbyname/getaddrinfo testing.  */
 193 static void
 194 subprocess_gethost (void *closure)
 195 {
 196   xchroot (chroot_env->path_chroot);
 197
 198   /* This tests enlarging the read buffer in the multi case.  */
 199   struct xmemstream expected;
 200   xopen_memstream (&expected);
 201   fputs ("name: host2.example.com\n", expected.out);
 202   for (int j = 1; j < name_count; ++j)
 203     /* NB: host2 is duplicated in the alias list.  */
 204     fprintf (expected.out, "alias: host%d.example.com\n", j);
 205   fputs ("alias: host0.example.com\n"
 206          "address: 192.0.2.2\n"
 207          "address: 192.0.2.1\n",
 208          expected.out);
 209   xfclose_memstream (&expected);
 210   check_hostent ("host2.example.com",
 211                  gethostbyname ("host2.example.com"),
 212                  expected.buffer);
 213   free (expected.buffer);
 214
 215   /* Similarly, but with a different order in the /etc/hosts file.  */
 216   xopen_memstream (&expected);
 217   fputs ("name: host0.example.com\n", expected.out);
 218   for (int j = 1; j < name_count; ++j)
 219     fprintf (expected.out, "alias: host%d.example.com\n", j);
 220   /* NB: host5 is duplicated in the alias list.  */
 221   fputs ("alias: host5.example.com\n"
 222          "address: 192.0.2.1\n"
 223          "address: 192.0.2.5\n",
 224          expected.out);
 225   xfclose_memstream (&expected);
 226   check_hostent ("host5.example.com",
 227                  gethostbyname ("host5.example.com"),
 228                  expected.buffer);
 229   free (expected.buffer);
 230
 231   check_hostent ("www.example.com",
 232                  gethostbyname ("www.example.com"),
 233                  host4_expected);
 234   check_hostent ("www1.example.com",
 235                  gethostbyname ("www1.example.com"),
 236                  host6_expected);
 237
 238   test_gai (AF_INET);
 239   test_gai (AF_UNSPEC);
 240 }
 241
 242 static int
 243 do_test (void)
 244 {
 245   support_become_root ();
 246   if (!support_can_chroot ())
 247     return EXIT_UNSUPPORTED;
 248
 249   __nss_configure_lookup ("hosts", "files");
 250   if (dlopen (LIBNSS_FILES_SO, RTLD_LAZY) == NULL)
 251     FAIL_EXIT1 ("could not load " LIBNSS_DNS_SO ": %s", dlerror ());
 252
 253   /* Each name takes about 20 bytes, so this covers a wide range of
 254      buffer sizes, from less than 1000 bytes to about 18000 bytes.  */
 255   for (name_count = 40; name_count <= 850; ++name_count)
 256     {
 257       write_hosts ();
 258
 259       for (do_stayopen = -1; do_stayopen < 2; ++do_stayopen)
 260         for (do_endent = 0; do_endent < 2; ++do_endent)
 261           {
 262             if (test_verbose > 0)
 263               printf ("info: name_count=%d do_stayopen=%d do_endent=%d\n",
 264                       name_count, do_stayopen, do_endent);
 265             support_isolate_in_subprocess (subprocess_getent, NULL);
 266           }
 267
 268       support_isolate_in_subprocess (subprocess_gethost, NULL);
 269     }
 270
 271   support_chroot_free (chroot_env);
 272   return 0;
 273 }
 274
 275 #define PREPARE prepare
 276 #include <support/test-driver.c>