Archipelago » qemu

/*

 * Block protocol for I/O error injection

 *

 * Copyright (c) 2010 Kevin Wolf <kwolf@redhat.com>

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "qemu-common.h"

#include "qemu/config-file.h"

#include "block/block_int.h"

#include "qemu/module.h"

typedef struct BDRVBlkdebugState {

    int state;

    int new_state;

    QLIST_HEAD(, BlkdebugRule) rules[BLKDBG_EVENT_MAX];

    QSIMPLEQ_HEAD(, BlkdebugRule) active_rules;

    QLIST_HEAD(, BlkdebugSuspendedReq) suspended_reqs;

} BDRVBlkdebugState;

typedef struct BlkdebugAIOCB {

    BlockDriverAIOCB common;

    QEMUBH *bh;

    int ret;

} BlkdebugAIOCB;

typedef struct BlkdebugSuspendedReq {

    Coroutine *co;

    char *tag;

    QLIST_ENTRY(BlkdebugSuspendedReq) next;

} BlkdebugSuspendedReq;

static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb);

static const AIOCBInfo blkdebug_aiocb_info = {

    .aiocb_size = sizeof(BlkdebugAIOCB),

    .cancel     = blkdebug_aio_cancel,

};

enum {

    ACTION_INJECT_ERROR,

    ACTION_SET_STATE,

    ACTION_SUSPEND,

};

typedef struct BlkdebugRule {

    BlkDebugEvent event;

    int action;

    int state;

    union {

        struct {

            int error;

            int immediately;

            int once;

            int64_t sector;

        } inject;

        struct {

            int new_state;

        } set_state;

        struct {

            char *tag;

        } suspend;

    } options;

    QLIST_ENTRY(BlkdebugRule) next;

    QSIMPLEQ_ENTRY(BlkdebugRule) active_next;

} BlkdebugRule;

static QemuOptsList inject_error_opts = {

    .name = "inject-error",

    .head = QTAILQ_HEAD_INITIALIZER(inject_error_opts.head),

    .desc = {

        {

            .name = "event",

            .type = QEMU_OPT_STRING,

        },

        {

            .name = "state",

            .type = QEMU_OPT_NUMBER,

        },

        {

            .name = "errno",

            .type = QEMU_OPT_NUMBER,

        },

        {

            .name = "sector",

            .type = QEMU_OPT_NUMBER,

        },

        {

            .name = "once",

            .type = QEMU_OPT_BOOL,

        },

        {

            .name = "immediately",

            .type = QEMU_OPT_BOOL,

        },

        { /* end of list */ }

    },

};

static QemuOptsList set_state_opts = {

    .name = "set-state",

    .head = QTAILQ_HEAD_INITIALIZER(set_state_opts.head),

    .desc = {

        {

            .name = "event",

            .type = QEMU_OPT_STRING,

        },

        {

            .name = "state",

            .type = QEMU_OPT_NUMBER,

        },

        {

            .name = "new_state",

            .type = QEMU_OPT_NUMBER,

        },

        { /* end of list */ }

    },

};

static QemuOptsList *config_groups[] = {

    &inject_error_opts,

    &set_state_opts,

    NULL

};

static const char *event_names[BLKDBG_EVENT_MAX] = {

    [BLKDBG_L1_UPDATE]                      = "l1_update",

    [BLKDBG_L1_GROW_ALLOC_TABLE]            = "l1_grow.alloc_table",

    [BLKDBG_L1_GROW_WRITE_TABLE]            = "l1_grow.write_table",

    [BLKDBG_L1_GROW_ACTIVATE_TABLE]         = "l1_grow.activate_table",

    [BLKDBG_L2_LOAD]                        = "l2_load",

    [BLKDBG_L2_UPDATE]                      = "l2_update",

    [BLKDBG_L2_UPDATE_COMPRESSED]           = "l2_update_compressed",

    [BLKDBG_L2_ALLOC_COW_READ]              = "l2_alloc.cow_read",

    [BLKDBG_L2_ALLOC_WRITE]                 = "l2_alloc.write",

    [BLKDBG_READ_AIO]                       = "read_aio",

    [BLKDBG_READ_BACKING_AIO]               = "read_backing_aio",

    [BLKDBG_READ_COMPRESSED]                = "read_compressed",

    [BLKDBG_WRITE_AIO]                      = "write_aio",

    [BLKDBG_WRITE_COMPRESSED]               = "write_compressed",

    [BLKDBG_VMSTATE_LOAD]                   = "vmstate_load",

    [BLKDBG_VMSTATE_SAVE]                   = "vmstate_save",

    [BLKDBG_COW_READ]                       = "cow_read",

    [BLKDBG_COW_WRITE]                      = "cow_write",

    [BLKDBG_REFTABLE_LOAD]                  = "reftable_load",

    [BLKDBG_REFTABLE_GROW]                  = "reftable_grow",

    [BLKDBG_REFBLOCK_LOAD]                  = "refblock_load",

    [BLKDBG_REFBLOCK_UPDATE]                = "refblock_update",

    [BLKDBG_REFBLOCK_UPDATE_PART]           = "refblock_update_part",

    [BLKDBG_REFBLOCK_ALLOC]                 = "refblock_alloc",

    [BLKDBG_REFBLOCK_ALLOC_HOOKUP]          = "refblock_alloc.hookup",

    [BLKDBG_REFBLOCK_ALLOC_WRITE]           = "refblock_alloc.write",

    [BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS]    = "refblock_alloc.write_blocks",

    [BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE]     = "refblock_alloc.write_table",

    [BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE]    = "refblock_alloc.switch_table",

    [BLKDBG_CLUSTER_ALLOC]                  = "cluster_alloc",

    [BLKDBG_CLUSTER_ALLOC_BYTES]            = "cluster_alloc_bytes",

    [BLKDBG_CLUSTER_FREE]                   = "cluster_free",

};

static int get_event_by_name(const char *name, BlkDebugEvent *event)

{

    int i;

    for (i = 0; i < BLKDBG_EVENT_MAX; i++) {

        if (!strcmp(event_names[i], name)) {

            *event = i;

            return 0;

        }

    }

    return -1;

}

struct add_rule_data {

    BDRVBlkdebugState *s;

    int action;

};

static int add_rule(QemuOpts *opts, void *opaque)

{

    struct add_rule_data *d = opaque;

    BDRVBlkdebugState *s = d->s;

    const char* event_name;

    BlkDebugEvent event;

    struct BlkdebugRule *rule;

    /* Find the right event for the rule */

    event_name = qemu_opt_get(opts, "event");

    if (!event_name || get_event_by_name(event_name, &event) < 0) {

        return -1;

    }

    /* Set attributes common for all actions */

    rule = g_malloc0(sizeof(*rule));

    *rule = (struct BlkdebugRule) {

        .event  = event,

        .action = d->action,

        .state  = qemu_opt_get_number(opts, "state", 0),

    };

    /* Parse action-specific options */

    switch (d->action) {

    case ACTION_INJECT_ERROR:

        rule->options.inject.error = qemu_opt_get_number(opts, "errno", EIO);

        rule->options.inject.once  = qemu_opt_get_bool(opts, "once", 0);

        rule->options.inject.immediately =

            qemu_opt_get_bool(opts, "immediately", 0);

        rule->options.inject.sector = qemu_opt_get_number(opts, "sector", -1);

        break;

    case ACTION_SET_STATE:

        rule->options.set_state.new_state =

            qemu_opt_get_number(opts, "new_state", 0);

        break;

    case ACTION_SUSPEND:

        rule->options.suspend.tag =

            g_strdup(qemu_opt_get(opts, "tag"));

        break;

    };

    /* Add the rule */

    QLIST_INSERT_HEAD(&s->rules[event], rule, next);

    return 0;

}

static void remove_rule(BlkdebugRule *rule)

{

    switch (rule->action) {

    case ACTION_INJECT_ERROR:

    case ACTION_SET_STATE:

        break;

    case ACTION_SUSPEND:

        g_free(rule->options.suspend.tag);

        break;

    }

    QLIST_REMOVE(rule, next);

    g_free(rule);

}

static int read_config(BDRVBlkdebugState *s, const char *filename)

{

    FILE *f;

    int ret;

    struct add_rule_data d;

    /* Allow usage without config file */

    if (!*filename) {

        return 0;

    }

    f = fopen(filename, "r");

    if (f == NULL) {

        return -errno;

    }

    ret = qemu_config_parse(f, config_groups, filename);

    if (ret < 0) {

        goto fail;

    }

    d.s = s;

    d.action = ACTION_INJECT_ERROR;

    qemu_opts_foreach(&inject_error_opts, add_rule, &d, 0);

    d.action = ACTION_SET_STATE;

    qemu_opts_foreach(&set_state_opts, add_rule, &d, 0);

    ret = 0;

fail:

    qemu_opts_reset(&inject_error_opts);

    qemu_opts_reset(&set_state_opts);

    fclose(f);

    return ret;

}

/* Valid blkdebug filenames look like blkdebug:path/to/config:path/to/image */

static int blkdebug_open(BlockDriverState *bs, const char *filename, int flags)

{

    BDRVBlkdebugState *s = bs->opaque;

    int ret;

    char *config, *c;

    /* Parse the blkdebug: prefix */

    if (strncmp(filename, "blkdebug:", strlen("blkdebug:"))) {

        return -EINVAL;

    }

    filename += strlen("blkdebug:");

    /* Read rules from config file */

    c = strchr(filename, ':');

    if (c == NULL) {

        return -EINVAL;

    }

    config = g_strdup(filename);

    config[c - filename] = '\0';

    ret = read_config(s, config);

    g_free(config);

    if (ret < 0) {

        return ret;

    }

    filename = c + 1;

    /* Set initial state */

    s->state = 1;

    /* Open the backing file */

    ret = bdrv_file_open(&bs->file, filename, flags);

    if (ret < 0) {

        return ret;

    }

    return 0;

}

static void error_callback_bh(void *opaque)

{

    struct BlkdebugAIOCB *acb = opaque;

    qemu_bh_delete(acb->bh);

    acb->common.cb(acb->common.opaque, acb->ret);

    qemu_aio_release(acb);

}

static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb)

{

    BlkdebugAIOCB *acb = container_of(blockacb, BlkdebugAIOCB, common);

    qemu_aio_release(acb);

}

static BlockDriverAIOCB *inject_error(BlockDriverState *bs,

    BlockDriverCompletionFunc *cb, void *opaque, BlkdebugRule *rule)

{

    BDRVBlkdebugState *s = bs->opaque;

    int error = rule->options.inject.error;

    struct BlkdebugAIOCB *acb;

    QEMUBH *bh;

    if (rule->options.inject.once) {

        QSIMPLEQ_INIT(&s->active_rules);

    }

    if (rule->options.inject.immediately) {

        return NULL;

    }

    acb = qemu_aio_get(&blkdebug_aiocb_info, bs, cb, opaque);

    acb->ret = -error;

    bh = qemu_bh_new(error_callback_bh, acb);

    acb->bh = bh;

    qemu_bh_schedule(bh);

    return &acb->common;

}

static BlockDriverAIOCB *blkdebug_aio_readv(BlockDriverState *bs,

    int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,

    BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVBlkdebugState *s = bs->opaque;

    BlkdebugRule *rule = NULL;

    QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {

        if (rule->options.inject.sector == -1 ||

            (rule->options.inject.sector >= sector_num &&

             rule->options.inject.sector < sector_num + nb_sectors)) {

            break;

        }

    }

    if (rule && rule->options.inject.error) {

        return inject_error(bs, cb, opaque, rule);

    }

    return bdrv_aio_readv(bs->file, sector_num, qiov, nb_sectors, cb, opaque);

}

static BlockDriverAIOCB *blkdebug_aio_writev(BlockDriverState *bs,

    int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,

    BlockDriverCompletionFunc *cb, void *opaque)

{

    BDRVBlkdebugState *s = bs->opaque;

    BlkdebugRule *rule = NULL;

    QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {

        if (rule->options.inject.sector == -1 ||

            (rule->options.inject.sector >= sector_num &&

             rule->options.inject.sector < sector_num + nb_sectors)) {

            break;

        }

    }

    if (rule && rule->options.inject.error) {

        return inject_error(bs, cb, opaque, rule);

    }

    return bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors, cb, opaque);

}

static void blkdebug_close(BlockDriverState *bs)

{

    BDRVBlkdebugState *s = bs->opaque;

    BlkdebugRule *rule, *next;

    int i;

    for (i = 0; i < BLKDBG_EVENT_MAX; i++) {

        QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {

            remove_rule(rule);

        }

    }

}

static void suspend_request(BlockDriverState *bs, BlkdebugRule *rule)

{

    BDRVBlkdebugState *s = bs->opaque;

    BlkdebugSuspendedReq r;

    r = (BlkdebugSuspendedReq) {

        .co         = qemu_coroutine_self(),

        .tag        = g_strdup(rule->options.suspend.tag),

    };

    remove_rule(rule);

    QLIST_INSERT_HEAD(&s->suspended_reqs, &r, next);

    printf("blkdebug: Suspended request '%s'\n", r.tag);

    qemu_coroutine_yield();

    printf("blkdebug: Resuming request '%s'\n", r.tag);

    QLIST_REMOVE(&r, next);

    g_free(r.tag);

}

static bool process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,

    bool injected)

{

    BDRVBlkdebugState *s = bs->opaque;

    /* Only process rules for the current state */

    if (rule->state && rule->state != s->state) {

        return injected;

    }

    /* Take the action */

    switch (rule->action) {

    case ACTION_INJECT_ERROR:

        if (!injected) {

            QSIMPLEQ_INIT(&s->active_rules);

            injected = true;

        }

        QSIMPLEQ_INSERT_HEAD(&s->active_rules, rule, active_next);

        break;

    case ACTION_SET_STATE:

        s->new_state = rule->options.set_state.new_state;

        break;

    case ACTION_SUSPEND:

        suspend_request(bs, rule);

        break;

    }

    return injected;

}

static void blkdebug_debug_event(BlockDriverState *bs, BlkDebugEvent event)

{

    BDRVBlkdebugState *s = bs->opaque;

    struct BlkdebugRule *rule, *next;

    bool injected;

    assert((int)event >= 0 && event < BLKDBG_EVENT_MAX);

    injected = false;

    s->new_state = s->state;

    QLIST_FOREACH_SAFE(rule, &s->rules[event], next, next) {

        injected = process_rule(bs, rule, injected);

    }

    s->state = s->new_state;

}

static int blkdebug_debug_breakpoint(BlockDriverState *bs, const char *event,

                                     const char *tag)

{

    BDRVBlkdebugState *s = bs->opaque;

    struct BlkdebugRule *rule;

    BlkDebugEvent blkdebug_event;

    if (get_event_by_name(event, &blkdebug_event) < 0) {

        return -ENOENT;

    }

    rule = g_malloc(sizeof(*rule));

    *rule = (struct BlkdebugRule) {

        .event  = blkdebug_event,

        .action = ACTION_SUSPEND,

        .state  = 0,

        .options.suspend.tag = g_strdup(tag),

    };

    QLIST_INSERT_HEAD(&s->rules[blkdebug_event], rule, next);

    return 0;

}

static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag)

{

    BDRVBlkdebugState *s = bs->opaque;

    BlkdebugSuspendedReq *r;

    QLIST_FOREACH(r, &s->suspended_reqs, next) {

        if (!strcmp(r->tag, tag)) {

            qemu_coroutine_enter(r->co, NULL);

            return 0;

        }

    }

    return -ENOENT;

}

static bool blkdebug_debug_is_suspended(BlockDriverState *bs, const char *tag)

{

    BDRVBlkdebugState *s = bs->opaque;

    BlkdebugSuspendedReq *r;

    QLIST_FOREACH(r, &s->suspended_reqs, next) {

        if (!strcmp(r->tag, tag)) {

            return true;

        }

    }

    return false;

}

static int64_t blkdebug_getlength(BlockDriverState *bs)

{

    return bdrv_getlength(bs->file);

}

static BlockDriver bdrv_blkdebug = {

    .format_name        = "blkdebug",

    .protocol_name      = "blkdebug",

    .instance_size      = sizeof(BDRVBlkdebugState),

    .bdrv_file_open     = blkdebug_open,

    .bdrv_close         = blkdebug_close,

    .bdrv_getlength     = blkdebug_getlength,

    .bdrv_aio_readv     = blkdebug_aio_readv,

    .bdrv_aio_writev    = blkdebug_aio_writev,

    .bdrv_debug_event           = blkdebug_debug_event,

    .bdrv_debug_breakpoint      = blkdebug_debug_breakpoint,

    .bdrv_debug_resume          = blkdebug_debug_resume,

    .bdrv_debug_is_suspended    = blkdebug_debug_is_suspended,

};

static void bdrv_blkdebug_init(void)

{

    bdrv_register(&bdrv_blkdebug);

}

block_init(bdrv_blkdebug_init);