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qemu-e2k/block/curl.c
Kevin Wolf 8dc7a7725b curl: Handle failure for potentially large allocations 
Some code in the block layer makes potentially huge allocations. Failure
is not completely unexpected there, so avoid aborting qemu and handle
out-of-memory situations gracefully.

This patch addresses the allocations in the curl block driver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
2014-08-15 15:07:15 +02:00

786 lines
22 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 "qapi/qmp/qbool.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
#if LIBCURL_VERSION_NUM >= 0x071000
/* The multi interface timer callback was introduced in 7.16.0 */
#define NEED_CURL_TIMER_CALLBACK
#define HAVE_SOCKET_ACTION
#endif
#ifndef HAVE_SOCKET_ACTION
/* If curl_multi_socket_action isn't available, define it statically here in
* terms of curl_multi_socket. Note that ev_bitmask will be ignored, which is
* less efficient but still safe. */
static CURLMcode __curl_multi_socket_action(CURLM *multi_handle,
curl_socket_t sockfd,
int ev_bitmask,
int *running_handles)
{
return curl_multi_socket(multi_handle, sockfd, running_handles);
}
#define curl_multi_socket_action __curl_multi_socket_action
#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_DEFAULT (256 * 1024)
#define FIND_RET_NONE 0
#define FIND_RET_OK 1
#define FIND_RET_WAIT 2
#define CURL_BLOCK_OPT_URL "url"
#define CURL_BLOCK_OPT_READAHEAD "readahead"
#define CURL_BLOCK_OPT_SSLVERIFY "sslverify"
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;
curl_socket_t sock_fd;
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;
QEMUTimer timer;
size_t len;
CURLState states[CURL_NUM_STATES];
char *url;
size_t readahead_size;
bool sslverify;
bool accept_range;
AioContext *aio_context;
} BDRVCURLState;
static void curl_clean_state(CURLState *s);
static void curl_multi_do(void *arg);
static void curl_multi_read(void *arg);
#ifdef NEED_CURL_TIMER_CALLBACK
static int curl_timer_cb(CURLM *multi, long timeout_ms, void *opaque)
{
BDRVCURLState *s = opaque;
DPRINTF("CURL: timer callback timeout_ms %ld\n", timeout_ms);
if (timeout_ms == -1) {
timer_del(&s->timer);
} else {
int64_t timeout_ns = (int64_t)timeout_ms * 1000 * 1000;
timer_mod(&s->timer,
qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + timeout_ns);
}
return 0;
}
#endif
static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
void *userp, void *sp)
{
BDRVCURLState *s;
CURLState *state = NULL;
curl_easy_getinfo(curl, CURLINFO_PRIVATE, (char **)&state);
state->sock_fd = fd;
s = state->s;
DPRINTF("CURL (AIO): Sock action %d on fd %d\n", action, fd);
switch (action) {
case CURL_POLL_IN:
aio_set_fd_handler(s->aio_context, fd, curl_multi_read,
NULL, state);
break;
case CURL_POLL_OUT:
aio_set_fd_handler(s->aio_context, fd, NULL, curl_multi_do, state);
break;
case CURL_POLL_INOUT:
aio_set_fd_handler(s->aio_context, fd, curl_multi_read,
curl_multi_do, state);
break;
case CURL_POLL_REMOVE:
aio_set_fd_handler(s->aio_context, fd, 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)
return 0;
if (s->buf_off >= s->buf_len) {
/* buffer full, read nothing */
return 0;
}
realsize = MIN(realsize, s->buf_len - s->buf_off);
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;
}
}
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 (state->in_use &&
(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_check_completion(BDRVCURLState *s)
{
int msgs_in_queue;
/* Try to find done transfers, so we can free the easy
* handle again. */
for (;;) {
CURLMsg *msg;
msg = curl_multi_info_read(s->multi, &msgs_in_queue);
/* Quit when there are no more completions */
if (!msg)
break;
if (msg->msg == 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;
}
}
}
static void curl_multi_do(void *arg)
{
CURLState *s = (CURLState *)arg;
int running;
int r;
if (!s->s->multi) {
return;
}
do {
r = curl_multi_socket_action(s->s->multi, s->sock_fd, 0, &running);
} while(r == CURLM_CALL_MULTI_PERFORM);
}
static void curl_multi_read(void *arg)
{
CURLState *s = (CURLState *)arg;
curl_multi_do(arg);
curl_multi_check_completion(s->s);
}
static void curl_multi_timeout_do(void *arg)
{
#ifdef NEED_CURL_TIMER_CALLBACK
BDRVCURLState *s = (BDRVCURLState *)arg;
int running;
if (!s->multi) {
return;
}
curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
curl_multi_check_completion(s);
#else
abort();
#endif
}
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) {
aio_poll(state->s->aio_context, true);
}
} while(!state);
if (!state->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_SSL_VERIFYPEER,
(long) s->sslverify);
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
}
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)
{
qdict_put(options, CURL_BLOCK_OPT_URL, qstring_from_str(filename));
}
static void curl_detach_aio_context(BlockDriverState *bs)
{
BDRVCURLState *s = bs->opaque;
int i;
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;
}
g_free(s->states[i].orig_buf);
s->states[i].orig_buf = NULL;
}
if (s->multi) {
curl_multi_cleanup(s->multi);
s->multi = NULL;
}
timer_del(&s->timer);
}
static void curl_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
BDRVCURLState *s = bs->opaque;
aio_timer_init(new_context, &s->timer,
QEMU_CLOCK_REALTIME, SCALE_NS,
curl_multi_timeout_do, s);
assert(!s->multi);
s->multi = curl_multi_init();
s->aio_context = new_context;
curl_multi_setopt(s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb);
#ifdef NEED_CURL_TIMER_CALLBACK
curl_multi_setopt(s->multi, CURLMOPT_TIMERDATA, s);
curl_multi_setopt(s->multi, CURLMOPT_TIMERFUNCTION, curl_timer_cb);
#endif
}
static QemuOptsList runtime_opts = {
.name = "curl",
.head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
.desc = {
{
.name = CURL_BLOCK_OPT_URL,
.type = QEMU_OPT_STRING,
.help = "URL to open",
},
{
.name = CURL_BLOCK_OPT_READAHEAD,
.type = QEMU_OPT_SIZE,
.help = "Readahead size",
},
{
.name = CURL_BLOCK_OPT_SSLVERIFY,
.type = QEMU_OPT_BOOL,
.help = "Verify SSL certificate"
},
{ /* end of list */ }
},
};
static int curl_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
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) {
error_setg(errp, "curl block device does not support writes");
return -EROFS;
}
opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
goto out_noclean;
}
s->readahead_size = qemu_opt_get_size(opts, CURL_BLOCK_OPT_READAHEAD,
READ_AHEAD_DEFAULT);
if ((s->readahead_size & 0x1ff) != 0) {
error_setg(errp, "HTTP_READAHEAD_SIZE %zd is not a multiple of 512",
s->readahead_size);
goto out_noclean;
}
s->sslverify = qemu_opt_get_bool(opts, CURL_BLOCK_OPT_SSLVERIFY, true);
file = qemu_opt_get(opts, CURL_BLOCK_OPT_URL);
if (file == NULL) {
error_setg(errp, "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->aio_context = bdrv_get_aio_context(bs);
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;
curl_attach_aio_context(bs, bdrv_get_aio_context(bs));
qemu_opts_del(opts);
return 0;
out:
error_setg(errp, "CURL: Error opening file: %s", 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;
int running;
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;
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_try_malloc(state->buf_len);
if (state->buf_len && state->orig_buf == NULL) {
curl_clean_state(state);
acb->common.cb(acb->common.opaque, -ENOMEM);
qemu_aio_release(acb);
return;
}
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);
/* Tell curl it needs to kick things off */
curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
}
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 = aio_bh_new(bdrv_get_aio_context(bs), curl_readv_bh_cb, acb);
qemu_bh_schedule(acb->bh);
return &acb->common;
}
static void curl_close(BlockDriverState *bs)
{
BDRVCURLState *s = bs->opaque;
DPRINTF("CURL: Close\n");
curl_detach_aio_context(bs);
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,
.bdrv_detach_aio_context = curl_detach_aio_context,
.bdrv_attach_aio_context = curl_attach_aio_context,
};
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,
.bdrv_detach_aio_context = curl_detach_aio_context,
.bdrv_attach_aio_context = curl_attach_aio_context,
};
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,
.bdrv_detach_aio_context = curl_detach_aio_context,
.bdrv_attach_aio_context = curl_attach_aio_context,
};
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,
.bdrv_detach_aio_context = curl_detach_aio_context,
.bdrv_attach_aio_context = curl_attach_aio_context,
};
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,
.bdrv_detach_aio_context = curl_detach_aio_context,
.bdrv_attach_aio_context = curl_attach_aio_context,
};
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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