tests/test-disconnect-plugin.c

   1 /* nbdkit
   2  * Copyright Red Hat
   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 <string.h>
  38 #include <stdbool.h>
  39
  40 #include <nbdkit-plugin.h>
  41
  42 static void
  43 disconnect_unload (void)
  44 {
  45   nbdkit_debug ("clean disconnect");
  46 }
  47
  48 static void *
  49 disconnect_open (int readonly)
  50 {
  51   return NBDKIT_HANDLE_NOT_NEEDED;
  52 }
  53
  54 static int64_t
  55 disconnect_get_size (void *handle)
  56 {
  57   return 1024*1024;
  58 }
  59
  60 #define THREAD_MODEL NBDKIT_THREAD_MODEL_PARALLEL
  61
  62 /* Reads are delayed to show effect of disconnect on in-flight commands */
  63 static int
  64 disconnect_pread (void *handle, void *buf, uint32_t count, uint64_t offset)
  65 {
  66   memset (buf, 0, count);
  67   if (nbdkit_nanosleep (2, 0) == -1)
  68     nbdkit_debug ("read delay ended early, returning success anyway");
  69   return 0;
  70 }
  71
  72 /* Writing causes a disconnect; export name determines severity. */
  73 static int
  74 disconnect_pwrite (void *handle, const void *buf, uint32_t count,
  75                    uint64_t offset)
  76 {
  77   const char *name = nbdkit_export_name ();
  78   bool hard = name && *name;
  79   nbdkit_debug ("%s disconnect triggered!", hard ? "hard" : "soft");
  80   nbdkit_disconnect (hard);
  81   /* Despite the disconnect, we still claim the write succeeded */
  82   return 0;
  83 }
  84
  85 static struct nbdkit_plugin plugin = {
  86   .name              = "disconnect",
  87   .version           = PACKAGE_VERSION,
  88   .unload            = disconnect_unload,
  89   .open              = disconnect_open,
  90   .get_size          = disconnect_get_size,
  91   .pread             = disconnect_pread,
  92   .pwrite            = disconnect_pwrite,
  93 };
  94
  95 NBDKIT_REGISTER_PLUGIN (plugin)