qemu-io-sim.c

   1 /*
   2  * Copyright (c) 2010-2011 IBM
   3  *
   4  * Authors:
   5  *         Chunqiang Tang <ctang@us.ibm.com>
   6  *
   7  * This work is licensed under the terms of the GNU GPL, version 2.
   8  * See the COPYING file in the top-level directory.
   9  */
  10
  11 /*=============================================================================
  12  * qemu-io-sim works with qemu-io to perform simulated testing. The 'sim'
  13  * command allows the user to control the order of disk I/O and callback
  14  * activities in order to test rare race conditions. Note that once 'sim
  15  * enable' is done, it can only test aio_read and aio_write. See block/sim.c
  16  * for the simulated block device driver.
  17  *============================================================================*/
  18
  19 #include "qemu/osdep.h"
  20 #include "block/blksim.h"
  21
  22 void fvd_init_prefetch (BlockDriverState * bs);
  23 static void sim_start_prefetch(BlockDriverState *bs)
  24 {
  25     if (!bs->drv->format_name || !strncmp (bs->drv->format_name, "fvd", 3)) {
  26         printf ("This image does not support prefetching.\n");
  27         return;
  28     }
  29     fvd_init_prefetch (bs);
  30     printf ("Prefetching started\n");
  31 }
  32
  33 static void sim_help (void)
  34 {
  35     printf ("\n"
  36             " sim enable\t\tenable simulation\n"
  37             " sim list\t\tlist all simulation tasks\n"
  38             " sim <#task> [#ret]\trun a simulation task, optionally uing #ret as the return value of a read/write operation\n"
  39             " sim all [#ret]\t\trun all tasks, optionally using #ret as the return value of read/write tasks\n"
  40             " sim prefetch\t\tstart prefetching\n");
  41 }
  42
  43 static int sim_f(BlockDriverState *bs, int argc, char **argv)
  44 {
  45     int ret = 0;
  46
  47     if (argc == 3) {
  48         ret = atoi (argv[2]);
  49     }
  50     else if (argc != 2) {
  51         sim_help ();
  52         return 0;
  53     }
  54
  55     if (strcmp (argv[1], "enable") == 0) {
  56         if (bs) {
  57             printf ("Please close the image first. \"sim enable\" must be done before the\n"
  58                     "image is opened so that the image is opened with simulation support.\n");
  59         }
  60         else {
  61             enable_block_sim(1/*print*/, 0 /*no random time*/);
  62             printf ("Block device simulation is enabled.\n");
  63         }
  64         return 0;
  65     }
  66
  67     if (!bs) {
  68         fprintf(stderr, "no file open, try 'help open'\n");
  69         return 0;
  70     }
  71
  72     if (!bdrv_find_format("blksim")) {
  73         printf ("\"sim enable\" must be done before invoking any other sim commands.\n");
  74         return 0;
  75     }
  76
  77     if (strcmp (argv[1], "list") == 0) {
  78         sim_list_tasks ();
  79     }
  80     else if (strcmp (argv[1], "prefetch") == 0) {
  81         sim_start_prefetch(bs);
  82     }
  83     else if (strcmp (argv[1], "all") == 0) {
  84         sim_set_disk_io_return_code (ret);
  85         int n = sim_all_tasks ();
  86         sim_set_disk_io_return_code (0);
  87         printf ("Executed %d tasks.\n", n);
  88     }
  89     else {
  90         sim_set_disk_io_return_code (ret);
  91         sim_task_by_uuid (atoll (argv[1]));
  92         sim_set_disk_io_return_code (0);
  93     }
  94
  95     return 0;
  96 }
  97
  98 static const cmdinfo_t sim_cmd = {
  99     .name = "sim",
 100     .altname = "s",
 101     .cfunc = sim_f,
 102     .argmin = 1,
 103     .argmax = 2,
 104     .args = "",
 105     .oneline = "use simulation to control the order of disk I/Os and callbacks",
 106     .flags = CMD_NOFILE_OK,
 107     .help = sim_help,
 108 };