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qemu/block/curl.c
Stefan Hajnoczi 0d1460226f block/curl: drop curl_aio_flush() 
.io_flush() is no longer called so drop curl_aio_flush().  The acb[]
array that the function checks is still used in other parts of
block/curl.c.  Therefore we cannot remove acb[], it is needed.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-08-19 15:45:35 +02:00

690 lines
19 KiB
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/*
* 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;
bool accept_range;
} BDRVCURLState;
static void curl_clean_state(CURLState *s);
static void curl_multi_do(void *arg);
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, NULL, s);
break;
case CURL_POLL_OUT:
qemu_aio_set_fd_handler(fd, NULL, curl_multi_do, NULL, s);
break;
case CURL_POLL_INOUT:
qemu_aio_set_fd_handler(fd, curl_multi_do, curl_multi_do,
NULL, s);
break;
case CURL_POLL_REMOVE:
qemu_aio_set_fd_handler(fd, NULL, NULL, NULL, NULL);
break;
}
return 0;
}
static size_t curl_header_cb(void *ptr, size_t size, size_t nmemb, void *opaque)
{
BDRVCURLState *s = opaque;
size_t realsize = size * nmemb;
const char *accept_line = "Accept-Ranges: bytes";
if (realsize >= strlen(accept_line)
&& strncmp((char *)ptr, accept_line, strlen(accept_line)) == 0) {
s->accept_range = true;
}
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, 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;
if (flags & BDRV_O_RDWR) {
qerror_report(ERROR_CLASS_GENERIC_ERROR,
"curl block device does not support writes");
return -EROFS;
}
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
s->accept_range = false;
curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
curl_easy_setopt(state->curl, CURLOPT_HEADERFUNCTION,
curl_header_cb);
curl_easy_setopt(state->curl, CURLOPT_HEADERDATA, s);
if (curl_easy_perform(state->curl))
goto out;
curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
if (d)
s->len = (size_t)d;
else if(!s->len)
goto out;
if ((!strncasecmp(s->url, "http://", strlen("http://"))
|| !strncasecmp(s->url, "https://", strlen("https://")))
&& !s->accept_range) {
pstrcpy(state->errmsg, CURL_ERROR_SIZE,
"Server does not support 'range' (byte ranges).");
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 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);
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