tests/test-stdio-plugin.c

   1 /* nbdkit
   2  * Copyright (C) 2013-2020 Red Hat Inc.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <config.h>
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <stdbool.h>
  38 #include <string.h>
  39 #include <fcntl.h>
  40 #include <unistd.h>
  41 #include <sys/stat.h>
  42
  43 #undef NDEBUG /* Keep test strong even for nbdkit built without assertions */
  44 #include <assert.h>
  45
  46 #define NBDKIT_API_VERSION 2
  47 #include <nbdkit-plugin.h>
  48
  49 #include "getline.h"
  50
  51 static const char *msg = "input";
  52
  53 /* Check whether stdin/out match /dev/null */
  54 static bool
  55 stdio_check (void)
  56 {
  57   static int dn = -1;
  58   struct stat st1, st2;
  59
  60   if (dn == -1) {
  61     dn = open ("/dev/null", O_RDONLY);
  62     assert (dn > STDERR_FILENO);
  63   }
  64   if (fstat (dn, &st1) == -1)
  65     assert (false);
  66
  67   if (fstat (STDIN_FILENO, &st2) == -1)
  68     assert (false);
  69   if (st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino)
  70     return false;
  71
  72   if (fstat (STDOUT_FILENO, &st2) == -1)
  73     assert (false);
  74   if (st1.st_dev != st2.st_dev || st1.st_ino != st2.st_ino)
  75     return false;
  76
  77   return true;
  78 }
  79
  80 static void
  81 stdio_dump_plugin (void)
  82 {
  83   char *buf = NULL;
  84   size_t len = 0;
  85   bool check = stdio_check ();
  86
  87   assert (check == false);
  88
  89   /* Reading from stdin during .dump_plugin is unusual, but not forbidden */
  90   if (getline (&buf, &len, stdin) == -1)
  91     assert (false);
  92   /* The point of .dump_plugin is to extend details sent to stdout */
  93   printf ("%s=%s\n", msg, buf);
  94   free (buf);
  95 }
  96
  97 static int
  98 stdio_config (const char *key, const char *value)
  99 {
 100   bool check = stdio_check ();
 101   assert (check == false);
 102   msg = key;
 103   return 0;
 104 }
 105
 106 static int
 107 stdio_config_complete (void)
 108 {
 109   bool check = stdio_check ();
 110   assert (check == false);
 111   if (nbdkit_stdio_safe ()) {
 112     char *buf = NULL;
 113     size_t len = 0;
 114
 115     /* Reading from stdin during .config_complete is safe except under -s */
 116     if (getline (&buf, &len, stdin) == -1)
 117       assert (false);
 118     /* Output during .config_complete is unusual, but not forbidden */
 119     printf ("%s=%s\n", msg, buf);
 120     free (buf);
 121   }
 122   return 0;
 123 }
 124
 125 static int
 126 stdio_get_ready (void)
 127 {
 128   bool check = stdio_check ();
 129   assert (check == false);
 130   return 0;
 131 }
 132
 133 static int
 134 stdio_after_fork (void)
 135 {
 136   bool check = stdio_check ();
 137   assert (check == true);
 138   return 0;
 139 }
 140
 141 static void *
 142 stdio_open (int readonly)
 143 {
 144   bool check = stdio_check ();
 145   assert (check == true);
 146   return NBDKIT_HANDLE_NOT_NEEDED;
 147 }
 148
 149 static int64_t
 150 stdio_get_size (void *handle)
 151 {
 152   bool check = stdio_check ();
 153   assert (check == true);
 154   return 1024*1024;
 155 }
 156
 157 #define THREAD_MODEL NBDKIT_THREAD_MODEL_PARALLEL
 158
 159 static int
 160 stdio_pread (void *handle, void *buf, uint32_t count, uint64_t offset,
 161              uint32_t flags)
 162 {
 163   bool check = stdio_check ();
 164   assert (check == true);
 165   memset (buf, 0, count);
 166   return 0;
 167 }
 168
 169 static struct nbdkit_plugin plugin = {
 170   .name              = "stdio",
 171   .version           = PACKAGE_VERSION,
 172   .dump_plugin       = stdio_dump_plugin,
 173   .config            = stdio_config,
 174   .config_complete   = stdio_config_complete,
 175   .get_ready         = stdio_get_ready,
 176   .after_fork        = stdio_after_fork,
 177   .open              = stdio_open,
 178   .get_size          = stdio_get_size,
 179   .pread             = stdio_pread,
 180 };
 181
 182 NBDKIT_REGISTER_PLUGIN(plugin)