Archipelago » qemu

/*

 * QEMU Block driver for CURL images

 *

 * Copyright (c) 2009 Alexander Graf <agraf@suse.de>

 *

 * 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 "block/block_int.h"

#include <curl/curl.h>

// #define DEBUG

// #define DEBUG_VERBOSE

#ifdef DEBUG_CURL

#define DPRINTF(fmt, ...) do { printf(fmt, ## __VA_ARGS__); } while (0)

#else

#define DPRINTF(fmt, ...) do { } while (0)

#endif

#define PROTOCOLS (CURLPROTO_HTTP | CURLPROTO_HTTPS | \

                   CURLPROTO_FTP | CURLPROTO_FTPS | \

                   CURLPROTO_TFTP)

#define CURL_NUM_STATES 8

#define CURL_NUM_ACB    8

#define SECTOR_SIZE     512

#define READ_AHEAD_SIZE (256 * 1024)

#define FIND_RET_NONE   0

#define FIND_RET_OK     1

#define FIND_RET_WAIT   2

struct BDRVCURLState;

typedef struct CURLAIOCB {

    BlockDriverAIOCB common;

    QEMUBH *bh;

    QEMUIOVector *qiov;

    int64_t sector_num;

    int nb_sectors;

    size_t start;

    size_t end;

} CURLAIOCB;

typedef struct CURLState

{

    struct BDRVCURLState *s;

    CURLAIOCB *acb[CURL_NUM_ACB];

    CURL *curl;

    char *orig_buf;

    size_t buf_start;

    size_t buf_off;

    size_t buf_len;

    char range[128];

    char errmsg[CURL_ERROR_SIZE];

    char in_use;

} CURLState;

typedef struct BDRVCURLState {

    CURLM *multi;

    size_t len;

    CURLState states[CURL_NUM_STATES];

    char *url;

    size_t readahead_size;

} BDRVCURLState;

static void curl_clean_state(CURLState *s);

static void curl_multi_do(void *arg);

static int curl_aio_flush(void *opaque);

static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,

                        void *s, void *sp)

{

    DPRINTF("CURL (AIO): Sock action %d on fd %d\n", action, fd);

    switch (action) {

        case CURL_POLL_IN:

            qemu_aio_set_fd_handler(fd, curl_multi_do, NULL, curl_aio_flush, s);

            break;

        case CURL_POLL_OUT:

            qemu_aio_set_fd_handler(fd, NULL, curl_multi_do, curl_aio_flush, s);

            break;

        case CURL_POLL_INOUT:

            qemu_aio_set_fd_handler(fd, curl_multi_do, curl_multi_do,

                                    curl_aio_flush, s);

            break;

        case CURL_POLL_REMOVE:

            qemu_aio_set_fd_handler(fd, NULL, NULL, NULL, NULL);

            break;

    }

    return 0;

}

static size_t curl_size_cb(void *ptr, size_t size, size_t nmemb, void *opaque)

{

    CURLState *s = ((CURLState*)opaque);

    size_t realsize = size * nmemb;

    size_t fsize;

    if(sscanf(ptr, "Content-Length: %zd", &fsize) == 1) {

        s->s->len = fsize;

    }

    return realsize;

}

static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)

{

    CURLState *s = ((CURLState*)opaque);

    size_t realsize = size * nmemb;

    int i;

    DPRINTF("CURL: Just reading %zd bytes\n", realsize);

    if (!s || !s->orig_buf)

        goto read_end;

    memcpy(s->orig_buf + s->buf_off, ptr, realsize);

    s->buf_off += realsize;

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

        CURLAIOCB *acb = s->acb[i];

        if (!acb)

            continue;

        if ((s->buf_off >= acb->end)) {

            qemu_iovec_from_buf(acb->qiov, 0, s->orig_buf + acb->start,

                                acb->end - acb->start);

            acb->common.cb(acb->common.opaque, 0);

            qemu_aio_release(acb);

            s->acb[i] = NULL;

        }

    }

read_end:

    return realsize;

}

static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len,

                         CURLAIOCB *acb)

{

    int i;

    size_t end = start + len;

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

        CURLState *state = &s->states[i];

        size_t buf_end = (state->buf_start + state->buf_off);

        size_t buf_fend = (state->buf_start + state->buf_len);

        if (!state->orig_buf)

            continue;

        if (!state->buf_off)

            continue;

        // Does the existing buffer cover our section?

        if ((start >= state->buf_start) &&

            (start <= buf_end) &&

            (end >= state->buf_start) &&

            (end <= buf_end))

        {

            char *buf = state->orig_buf + (start - state->buf_start);

            qemu_iovec_from_buf(acb->qiov, 0, buf, len);

            acb->common.cb(acb->common.opaque, 0);

            return FIND_RET_OK;

        }

        // Wait for unfinished chunks

        if ((start >= state->buf_start) &&

            (start <= buf_fend) &&

            (end >= state->buf_start) &&

            (end <= buf_fend))

        {

            int j;

            acb->start = start - state->buf_start;

            acb->end = acb->start + len;

            for (j=0; j<CURL_NUM_ACB; j++) {

                if (!state->acb[j]) {

                    state->acb[j] = acb;

                    return FIND_RET_WAIT;

                }

            }

        }

    }

    return FIND_RET_NONE;

}

static void curl_multi_do(void *arg)

{

    BDRVCURLState *s = (BDRVCURLState *)arg;

    int running;

    int r;

    int msgs_in_queue;

    if (!s->multi)

        return;

    do {

        r = curl_multi_socket_all(s->multi, &running);

    } while(r == CURLM_CALL_MULTI_PERFORM);

    /* Try to find done transfers, so we can free the easy

     * handle again. */

    do {

        CURLMsg *msg;

        msg = curl_multi_info_read(s->multi, &msgs_in_queue);

        if (!msg)

            break;

        if (msg->msg == CURLMSG_NONE)

            break;

        switch (msg->msg) {

            case CURLMSG_DONE:

            {

                CURLState *state = NULL;

                curl_easy_getinfo(msg->easy_handle, CURLINFO_PRIVATE, (char**)&state);

                /* ACBs for successful messages get completed in curl_read_cb */

                if (msg->data.result != CURLE_OK) {

                    int i;

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

                        CURLAIOCB *acb = state->acb[i];

                        if (acb == NULL) {

                            continue;

                        }

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

                        qemu_aio_release(acb);

                        state->acb[i] = NULL;

                    }

                }

                curl_clean_state(state);

                break;

            }

            default:

                msgs_in_queue = 0;

                break;

        }

    } while(msgs_in_queue);

}

static CURLState *curl_init_state(BDRVCURLState *s)

{

    CURLState *state = NULL;

    int i, j;

    do {

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

            for (j=0; j<CURL_NUM_ACB; j++)

                if (s->states[i].acb[j])

                    continue;

            if (s->states[i].in_use)

                continue;

            state = &s->states[i];

            state->in_use = 1;

            break;

        }

        if (!state) {

            g_usleep(100);

            curl_multi_do(s);

        }

    } while(!state);

    if (state->curl)

        goto has_curl;

    state->curl = curl_easy_init();

    if (!state->curl)

        return NULL;

    curl_easy_setopt(state->curl, CURLOPT_URL, s->url);

    curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, 5);

    curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_read_cb);

    curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);

    curl_easy_setopt(state->curl, CURLOPT_PRIVATE, (void *)state);

    curl_easy_setopt(state->curl, CURLOPT_AUTOREFERER, 1);

    curl_easy_setopt(state->curl, CURLOPT_FOLLOWLOCATION, 1);

    curl_easy_setopt(state->curl, CURLOPT_NOSIGNAL, 1);

    curl_easy_setopt(state->curl, CURLOPT_ERRORBUFFER, state->errmsg);

    curl_easy_setopt(state->curl, CURLOPT_FAILONERROR, 1);

    /* Restrict supported protocols to avoid security issues in the more

     * obscure protocols.  For example, do not allow POP3/SMTP/IMAP see

     * CVE-2013-0249.

     *

     * Restricting protocols is only supported from 7.19.4 upwards.

     */

#if LIBCURL_VERSION_NUM >= 0x071304

    curl_easy_setopt(state->curl, CURLOPT_PROTOCOLS, PROTOCOLS);

    curl_easy_setopt(state->curl, CURLOPT_REDIR_PROTOCOLS, PROTOCOLS);

#endif

#ifdef DEBUG_VERBOSE

    curl_easy_setopt(state->curl, CURLOPT_VERBOSE, 1);

#endif

has_curl:

    state->s = s;

    return state;

}

static void curl_clean_state(CURLState *s)

{

    if (s->s->multi)

        curl_multi_remove_handle(s->s->multi, s->curl);

    s->in_use = 0;

}

static void curl_parse_filename(const char *filename, QDict *options,

                                Error **errp)

{

    #define RA_OPTSTR ":readahead="

    char *file;

    char *ra;

    const char *ra_val;

    int parse_state = 0;

    file = g_strdup(filename);

    /* Parse a trailing ":readahead=#:" param, if present. */

    ra = file + strlen(file) - 1;

    while (ra >= file) {

        if (parse_state == 0) {

            if (*ra == ':') {

                parse_state++;

            } else {

                break;

            }

        } else if (parse_state == 1) {

            if (*ra > '9' || *ra < '0') {

                char *opt_start = ra - strlen(RA_OPTSTR) + 1;

                if (opt_start > file &&

                    strncmp(opt_start, RA_OPTSTR, strlen(RA_OPTSTR)) == 0) {

                    ra_val = ra + 1;

                    ra -= strlen(RA_OPTSTR) - 1;

                    *ra = '\0';

                    qdict_put(options, "readahead", qstring_from_str(ra_val));

                }

                break;

            }

        }

        ra--;

    }

    qdict_put(options, "url", qstring_from_str(file));

    g_free(file);

}

static QemuOptsList runtime_opts = {

    .name = "curl",

    .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),

    .desc = {

        {

            .name = "url",

            .type = QEMU_OPT_STRING,

            .help = "URL to open",

        },

        {

            .name = "readahead",

            .type = QEMU_OPT_SIZE,

            .help = "Readahead size",

        },

        { /* end of list */ }

    },

};

static int curl_open(BlockDriverState *bs, const char *dummy,

                     QDict *options, int flags)

{

    BDRVCURLState *s = bs->opaque;

    CURLState *state = NULL;

    QemuOpts *opts;

    Error *local_err = NULL;

    const char *file;

    double d;

    static int inited = 0;

    opts = qemu_opts_create_nofail(&runtime_opts);

    qemu_opts_absorb_qdict(opts, options, &local_err);

    if (error_is_set(&local_err)) {

        qerror_report_err(local_err);

        error_free(local_err);

        goto out_noclean;

    }

    s->readahead_size = qemu_opt_get_size(opts, "readahead", READ_AHEAD_SIZE);

    if ((s->readahead_size & 0x1ff) != 0) {

        fprintf(stderr, "HTTP_READAHEAD_SIZE %zd is not a multiple of 512\n",

                s->readahead_size);

        goto out_noclean;

    }

    file = qemu_opt_get(opts, "url");

    if (file == NULL) {

        qerror_report(ERROR_CLASS_GENERIC_ERROR, "curl block driver requires "

                      "an 'url' option");

        goto out_noclean;

    }

    if (!inited) {

        curl_global_init(CURL_GLOBAL_ALL);

        inited = 1;

    }

    DPRINTF("CURL: Opening %s\n", file);

    s->url = g_strdup(file);

    state = curl_init_state(s);

    if (!state)

        goto out_noclean;

    // Get file size

    curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);

    curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_size_cb);

    if (curl_easy_perform(state->curl))

        goto out;

    curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);

    curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION, (void *)curl_read_cb);

    curl_easy_setopt(state->curl, CURLOPT_NOBODY, 0);

    if (d)

        s->len = (size_t)d;

    else if(!s->len)

        goto out;

    DPRINTF("CURL: Size = %zd\n", s->len);

    curl_clean_state(state);

    curl_easy_cleanup(state->curl);

    state->curl = NULL;

    // Now we know the file exists and its size, so let's

    // initialize the multi interface!

    s->multi = curl_multi_init();

    curl_multi_setopt( s->multi, CURLMOPT_SOCKETDATA, s); 

    curl_multi_setopt( s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb ); 

    curl_multi_do(s);

    qemu_opts_del(opts);

    return 0;

out:

    fprintf(stderr, "CURL: Error opening file: %s\n", state->errmsg);

    curl_easy_cleanup(state->curl);

    state->curl = NULL;

out_noclean:

    g_free(s->url);

    qemu_opts_del(opts);

    return -EINVAL;

}

static int curl_aio_flush(void *opaque)

{

    BDRVCURLState *s = opaque;

    int i, j;

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

        for(j=0; j < CURL_NUM_ACB; j++) {

            if (s->states[i].acb[j]) {

                return 1;

            }

        }

    }

    return 0;

}

static void curl_aio_cancel(BlockDriverAIOCB *blockacb)

{

    // Do we have to implement canceling? Seems to work without...

}

static const AIOCBInfo curl_aiocb_info = {

    .aiocb_size         = sizeof(CURLAIOCB),

    .cancel             = curl_aio_cancel,

};

static void curl_readv_bh_cb(void *p)

{

    CURLState *state;

    CURLAIOCB *acb = p;

    BDRVCURLState *s = acb->common.bs->opaque;

    qemu_bh_delete(acb->bh);

    acb->bh = NULL;

    size_t start = acb->sector_num * SECTOR_SIZE;

    size_t end;

    // In case we have the requested data already (e.g. read-ahead),

    // we can just call the callback and be done.

    switch (curl_find_buf(s, start, acb->nb_sectors * SECTOR_SIZE, acb)) {

        case FIND_RET_OK:

            qemu_aio_release(acb);

            // fall through

        case FIND_RET_WAIT:

            return;

        default:

            break;

    }

    // No cache found, so let's start a new request

    state = curl_init_state(s);

    if (!state) {

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

        qemu_aio_release(acb);

        return;

    }

    acb->start = 0;

    acb->end = (acb->nb_sectors * SECTOR_SIZE);

    state->buf_off = 0;

    if (state->orig_buf)

        g_free(state->orig_buf);

    state->buf_start = start;

    state->buf_len = acb->end + s->readahead_size;

    end = MIN(start + state->buf_len, s->len) - 1;

    state->orig_buf = g_malloc(state->buf_len);

    state->acb[0] = acb;

    snprintf(state->range, 127, "%zd-%zd", start, end);

    DPRINTF("CURL (AIO): Reading %d at %zd (%s)\n",

            (acb->nb_sectors * SECTOR_SIZE), start, state->range);

    curl_easy_setopt(state->curl, CURLOPT_RANGE, state->range);

    curl_multi_add_handle(s->multi, state->curl);

    curl_multi_do(s);

}

static BlockDriverAIOCB *curl_aio_readv(BlockDriverState *bs,

        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,

        BlockDriverCompletionFunc *cb, void *opaque)

{

    CURLAIOCB *acb;

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

    acb->qiov = qiov;

    acb->sector_num = sector_num;

    acb->nb_sectors = nb_sectors;

    acb->bh = qemu_bh_new(curl_readv_bh_cb, acb);

    if (!acb->bh) {

        DPRINTF("CURL: qemu_bh_new failed\n");

        return NULL;

    }

    qemu_bh_schedule(acb->bh);

    return &acb->common;

}

static void curl_close(BlockDriverState *bs)

{

    BDRVCURLState *s = bs->opaque;

    int i;

    DPRINTF("CURL: Close\n");

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

        if (s->states[i].in_use)

            curl_clean_state(&s->states[i]);

        if (s->states[i].curl) {

            curl_easy_cleanup(s->states[i].curl);

            s->states[i].curl = NULL;

        }

        if (s->states[i].orig_buf) {

            g_free(s->states[i].orig_buf);

            s->states[i].orig_buf = NULL;

        }

    }

    if (s->multi)

        curl_multi_cleanup(s->multi);

    g_free(s->url);

}

static int64_t curl_getlength(BlockDriverState *bs)

{

    BDRVCURLState *s = bs->opaque;

    return s->len;

}

static BlockDriver bdrv_http = {

    .format_name            = "http",

    .protocol_name          = "http",

    .instance_size          = sizeof(BDRVCURLState),

    .bdrv_parse_filename    = curl_parse_filename,

    .bdrv_file_open         = curl_open,

    .bdrv_close             = curl_close,

    .bdrv_getlength         = curl_getlength,

    .bdrv_aio_readv         = curl_aio_readv,

};

static BlockDriver bdrv_https = {

    .format_name            = "https",

    .protocol_name          = "https",

    .instance_size          = sizeof(BDRVCURLState),

    .bdrv_parse_filename    = curl_parse_filename,

    .bdrv_file_open         = curl_open,

    .bdrv_close             = curl_close,

    .bdrv_getlength         = curl_getlength,

    .bdrv_aio_readv         = curl_aio_readv,

};

static BlockDriver bdrv_ftp = {

    .format_name            = "ftp",

    .protocol_name          = "ftp",

    .instance_size          = sizeof(BDRVCURLState),

    .bdrv_parse_filename    = curl_parse_filename,

    .bdrv_file_open         = curl_open,

    .bdrv_close             = curl_close,

    .bdrv_getlength         = curl_getlength,

    .bdrv_aio_readv         = curl_aio_readv,

};

static BlockDriver bdrv_ftps = {

    .format_name            = "ftps",

    .protocol_name          = "ftps",

    .instance_size          = sizeof(BDRVCURLState),

    .bdrv_parse_filename    = curl_parse_filename,

    .bdrv_file_open         = curl_open,

    .bdrv_close             = curl_close,

    .bdrv_getlength         = curl_getlength,

    .bdrv_aio_readv         = curl_aio_readv,

};

static BlockDriver bdrv_tftp = {

    .format_name            = "tftp",

    .protocol_name          = "tftp",

    .instance_size          = sizeof(BDRVCURLState),

    .bdrv_parse_filename    = curl_parse_filename,

    .bdrv_file_open         = curl_open,

    .bdrv_close             = curl_close,

    .bdrv_getlength         = curl_getlength,

    .bdrv_aio_readv         = curl_aio_readv,

};

static void curl_block_init(void)

{

    bdrv_register(&bdrv_http);

    bdrv_register(&bdrv_https);

    bdrv_register(&bdrv_ftp);

    bdrv_register(&bdrv_ftps);

    bdrv_register(&bdrv_tftp);

}

block_init(curl_block_init);