2 * Secure Shell (ssh) backend for QEMU.
4 * Copyright (C) 2013 Red Hat Inc., Richard W.M. Jones <rjones@redhat.com>
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
30 #include <libssh2_sftp.h>
32 #include "block/block_int.h"
33 #include "qemu/error-report.h"
34 #include "qemu/sockets.h"
36 #include "qapi/qmp/qint.h"
37 #include "qapi/qmp/qstring.h"
39 /* DEBUG_SSH=1 enables the DPRINTF (debugging printf) statements in
40 * this block driver code.
42 * TRACE_LIBSSH2=<bitmask> enables tracing in libssh2 itself. Note
43 * that this requires that libssh2 was specially compiled with the
44 * `./configure --enable-debug' option, so most likely you will have
45 * to compile it yourself. The meaning of <bitmask> is described
46 * here: http://www.libssh2.org/libssh2_trace.html
49 #define TRACE_LIBSSH2 0 /* or try: LIBSSH2_TRACE_SFTP */
51 #define DPRINTF(fmt, ...) \
54 fprintf(stderr, "ssh: %-15s " fmt "\n", \
55 __func__, ##__VA_ARGS__); \
59 typedef struct BDRVSSHState
{
64 int sock
; /* socket */
65 LIBSSH2_SESSION
*session
; /* ssh session */
66 LIBSSH2_SFTP
*sftp
; /* sftp session */
67 LIBSSH2_SFTP_HANDLE
*sftp_handle
; /* sftp remote file handle */
69 /* See ssh_seek() function below. */
73 /* File attributes at open. We try to keep the .filesize field
74 * updated if it changes (eg by writing at the end of the file).
76 LIBSSH2_SFTP_ATTRIBUTES attrs
;
78 /* Used to warn if 'flush' is not supported. */
80 bool unsafe_flush_warning
;
83 static void ssh_state_init(BDRVSSHState
*s
)
85 memset(s
, 0, sizeof *s
);
88 qemu_co_mutex_init(&s
->lock
);
91 static void ssh_state_free(BDRVSSHState
*s
)
95 libssh2_sftp_close(s
->sftp_handle
);
98 libssh2_sftp_shutdown(s
->sftp
);
101 libssh2_session_disconnect(s
->session
,
102 "from qemu ssh client: "
103 "user closed the connection");
104 libssh2_session_free(s
->session
);
111 static void GCC_FMT_ATTR(3, 4)
112 session_error_setg(Error
**errp
, BDRVSSHState
*s
, const char *fs
, ...)
118 msg
= g_strdup_vprintf(fs
, args
);
125 /* This is not an errno. See <libssh2.h>. */
126 ssh_err_code
= libssh2_session_last_error(s
->session
,
128 error_setg(errp
, "%s: %s (libssh2 error code: %d)",
129 msg
, ssh_err
, ssh_err_code
);
131 error_setg(errp
, "%s", msg
);
136 static void GCC_FMT_ATTR(3, 4)
137 sftp_error_setg(Error
**errp
, BDRVSSHState
*s
, const char *fs
, ...)
143 msg
= g_strdup_vprintf(fs
, args
);
149 unsigned long sftp_err_code
;
151 /* This is not an errno. See <libssh2.h>. */
152 ssh_err_code
= libssh2_session_last_error(s
->session
,
154 /* See <libssh2_sftp.h>. */
155 sftp_err_code
= libssh2_sftp_last_error((s
)->sftp
);
158 "%s: %s (libssh2 error code: %d, sftp error code: %lu)",
159 msg
, ssh_err
, ssh_err_code
, sftp_err_code
);
161 error_setg(errp
, "%s", msg
);
166 static void GCC_FMT_ATTR(2, 3)
167 sftp_error_report(BDRVSSHState
*s
, const char *fs
, ...)
172 error_vprintf(fs
, args
);
177 unsigned long sftp_err_code
;
179 /* This is not an errno. See <libssh2.h>. */
180 ssh_err_code
= libssh2_session_last_error(s
->session
,
182 /* See <libssh2_sftp.h>. */
183 sftp_err_code
= libssh2_sftp_last_error((s
)->sftp
);
185 error_printf(": %s (libssh2 error code: %d, sftp error code: %lu)",
186 ssh_err
, ssh_err_code
, sftp_err_code
);
193 static int parse_uri(const char *filename
, QDict
*options
, Error
**errp
)
196 QueryParams
*qp
= NULL
;
199 uri
= uri_parse(filename
);
204 if (strcmp(uri
->scheme
, "ssh") != 0) {
205 error_setg(errp
, "URI scheme must be 'ssh'");
209 if (!uri
->server
|| strcmp(uri
->server
, "") == 0) {
210 error_setg(errp
, "missing hostname in URI");
214 if (!uri
->path
|| strcmp(uri
->path
, "") == 0) {
215 error_setg(errp
, "missing remote path in URI");
219 qp
= query_params_parse(uri
->query
);
221 error_setg(errp
, "could not parse query parameters");
225 if(uri
->user
&& strcmp(uri
->user
, "") != 0) {
226 qdict_put(options
, "user", qstring_from_str(uri
->user
));
229 qdict_put(options
, "host", qstring_from_str(uri
->server
));
232 qdict_put(options
, "port", qint_from_int(uri
->port
));
235 qdict_put(options
, "path", qstring_from_str(uri
->path
));
237 /* Pick out any query parameters that we understand, and ignore
240 for (i
= 0; i
< qp
->n
; ++i
) {
241 if (strcmp(qp
->p
[i
].name
, "host_key_check") == 0) {
242 qdict_put(options
, "host_key_check",
243 qstring_from_str(qp
->p
[i
].value
));
247 query_params_free(qp
);
253 query_params_free(qp
);
261 static void ssh_parse_filename(const char *filename
, QDict
*options
,
264 if (qdict_haskey(options
, "user") ||
265 qdict_haskey(options
, "host") ||
266 qdict_haskey(options
, "port") ||
267 qdict_haskey(options
, "path") ||
268 qdict_haskey(options
, "host_key_check")) {
269 error_setg(errp
, "user, host, port, path, host_key_check cannot be used at the same time as a file option");
273 parse_uri(filename
, options
, errp
);
276 static int check_host_key_knownhosts(BDRVSSHState
*s
,
277 const char *host
, int port
, Error
**errp
)
280 char *knh_file
= NULL
;
281 LIBSSH2_KNOWNHOSTS
*knh
= NULL
;
282 struct libssh2_knownhost
*found
;
288 hostkey
= libssh2_session_hostkey(s
->session
, &len
, &type
);
291 session_error_setg(errp
, s
, "failed to read remote host key");
295 knh
= libssh2_knownhost_init(s
->session
);
298 session_error_setg(errp
, s
,
299 "failed to initialize known hosts support");
303 home
= getenv("HOME");
305 knh_file
= g_strdup_printf("%s/.ssh/known_hosts", home
);
307 knh_file
= g_strdup_printf("/root/.ssh/known_hosts");
310 /* Read all known hosts from OpenSSH-style known_hosts file. */
311 libssh2_knownhost_readfile(knh
, knh_file
, LIBSSH2_KNOWNHOST_FILE_OPENSSH
);
313 r
= libssh2_knownhost_checkp(knh
, host
, port
, hostkey
, len
,
314 LIBSSH2_KNOWNHOST_TYPE_PLAIN
|
315 LIBSSH2_KNOWNHOST_KEYENC_RAW
,
318 case LIBSSH2_KNOWNHOST_CHECK_MATCH
:
320 DPRINTF("host key OK: %s", found
->key
);
322 case LIBSSH2_KNOWNHOST_CHECK_MISMATCH
:
324 session_error_setg(errp
, s
,
325 "host key does not match the one in known_hosts"
326 " (found key %s)", found
->key
);
328 case LIBSSH2_KNOWNHOST_CHECK_NOTFOUND
:
330 session_error_setg(errp
, s
, "no host key was found in known_hosts");
332 case LIBSSH2_KNOWNHOST_CHECK_FAILURE
:
334 session_error_setg(errp
, s
,
335 "failure matching the host key with known_hosts");
339 session_error_setg(errp
, s
, "unknown error matching the host key"
340 " with known_hosts (%d)", r
);
344 /* known_hosts checking successful. */
349 libssh2_knownhost_free(knh
);
355 static unsigned hex2decimal(char ch
)
357 if (ch
>= '0' && ch
<= '9') {
359 } else if (ch
>= 'a' && ch
<= 'f') {
360 return 10 + (ch
- 'a');
361 } else if (ch
>= 'A' && ch
<= 'F') {
362 return 10 + (ch
- 'A');
368 /* Compare the binary fingerprint (hash of host key) with the
369 * host_key_check parameter.
371 static int compare_fingerprint(const unsigned char *fingerprint
, size_t len
,
372 const char *host_key_check
)
377 while (*host_key_check
== ':')
379 if (!qemu_isxdigit(host_key_check
[0]) ||
380 !qemu_isxdigit(host_key_check
[1]))
382 c
= hex2decimal(host_key_check
[0]) * 16 +
383 hex2decimal(host_key_check
[1]);
384 if (c
- *fingerprint
!= 0)
385 return c
- *fingerprint
;
390 return *host_key_check
- '\0';
394 check_host_key_hash(BDRVSSHState
*s
, const char *hash
,
395 int hash_type
, size_t fingerprint_len
, Error
**errp
)
397 const char *fingerprint
;
399 fingerprint
= libssh2_hostkey_hash(s
->session
, hash_type
);
401 session_error_setg(errp
, s
, "failed to read remote host key");
405 if(compare_fingerprint((unsigned char *) fingerprint
, fingerprint_len
,
407 error_setg(errp
, "remote host key does not match host_key_check '%s'",
415 static int check_host_key(BDRVSSHState
*s
, const char *host
, int port
,
416 const char *host_key_check
, Error
**errp
)
418 /* host_key_check=no */
419 if (strcmp(host_key_check
, "no") == 0) {
423 /* host_key_check=md5:xx:yy:zz:... */
424 if (strncmp(host_key_check
, "md5:", 4) == 0) {
425 return check_host_key_hash(s
, &host_key_check
[4],
426 LIBSSH2_HOSTKEY_HASH_MD5
, 16, errp
);
429 /* host_key_check=sha1:xx:yy:zz:... */
430 if (strncmp(host_key_check
, "sha1:", 5) == 0) {
431 return check_host_key_hash(s
, &host_key_check
[5],
432 LIBSSH2_HOSTKEY_HASH_SHA1
, 20, errp
);
435 /* host_key_check=yes */
436 if (strcmp(host_key_check
, "yes") == 0) {
437 return check_host_key_knownhosts(s
, host
, port
, errp
);
440 error_setg(errp
, "unknown host_key_check setting (%s)", host_key_check
);
444 static int authenticate(BDRVSSHState
*s
, const char *user
, Error
**errp
)
447 const char *userauthlist
;
448 LIBSSH2_AGENT
*agent
= NULL
;
449 struct libssh2_agent_publickey
*identity
;
450 struct libssh2_agent_publickey
*prev_identity
= NULL
;
452 userauthlist
= libssh2_userauth_list(s
->session
, user
, strlen(user
));
453 if (strstr(userauthlist
, "publickey") == NULL
) {
456 "remote server does not support \"publickey\" authentication");
460 /* Connect to ssh-agent and try each identity in turn. */
461 agent
= libssh2_agent_init(s
->session
);
464 session_error_setg(errp
, s
, "failed to initialize ssh-agent support");
467 if (libssh2_agent_connect(agent
)) {
469 session_error_setg(errp
, s
, "failed to connect to ssh-agent");
472 if (libssh2_agent_list_identities(agent
)) {
474 session_error_setg(errp
, s
,
475 "failed requesting identities from ssh-agent");
480 r
= libssh2_agent_get_identity(agent
, &identity
, prev_identity
);
481 if (r
== 1) { /* end of list */
486 session_error_setg(errp
, s
,
487 "failed to obtain identity from ssh-agent");
490 r
= libssh2_agent_userauth(agent
, user
, identity
);
496 /* Failed to authenticate with this identity, try the next one. */
497 prev_identity
= identity
;
501 error_setg(errp
, "failed to authenticate using publickey authentication "
502 "and the identities held by your ssh-agent");
506 /* Note: libssh2 implementation implicitly calls
507 * libssh2_agent_disconnect if necessary.
509 libssh2_agent_free(agent
);
515 static int connect_to_ssh(BDRVSSHState
*s
, QDict
*options
,
516 int ssh_flags
, int creat_mode
, Error
**errp
)
519 const char *host
, *user
, *path
, *host_key_check
;
522 if (!qdict_haskey(options
, "host")) {
524 error_setg(errp
, "No hostname was specified");
527 host
= qdict_get_str(options
, "host");
529 if (qdict_haskey(options
, "port")) {
530 port
= qdict_get_int(options
, "port");
535 if (!qdict_haskey(options
, "path")) {
537 error_setg(errp
, "No path was specified");
540 path
= qdict_get_str(options
, "path");
542 if (qdict_haskey(options
, "user")) {
543 user
= qdict_get_str(options
, "user");
545 user
= g_get_user_name();
547 error_setg_errno(errp
, errno
, "Can't get user name");
553 if (qdict_haskey(options
, "host_key_check")) {
554 host_key_check
= qdict_get_str(options
, "host_key_check");
556 host_key_check
= "yes";
559 /* Construct the host:port name for inet_connect. */
561 s
->hostport
= g_strdup_printf("%s:%d", host
, port
);
563 /* Open the socket and connect. */
564 s
->sock
= inet_connect(s
->hostport
, errp
);
570 /* Create SSH session. */
571 s
->session
= libssh2_session_init();
574 session_error_setg(errp
, s
, "failed to initialize libssh2 session");
578 #if TRACE_LIBSSH2 != 0
579 libssh2_trace(s
->session
, TRACE_LIBSSH2
);
582 r
= libssh2_session_handshake(s
->session
, s
->sock
);
585 session_error_setg(errp
, s
, "failed to establish SSH session");
589 /* Check the remote host's key against known_hosts. */
590 ret
= check_host_key(s
, host
, port
, host_key_check
, errp
);
596 ret
= authenticate(s
, user
, errp
);
602 s
->sftp
= libssh2_sftp_init(s
->session
);
604 session_error_setg(errp
, s
, "failed to initialize sftp handle");
609 /* Open the remote file. */
610 DPRINTF("opening file %s flags=0x%x creat_mode=0%o",
611 path
, ssh_flags
, creat_mode
);
612 s
->sftp_handle
= libssh2_sftp_open(s
->sftp
, path
, ssh_flags
, creat_mode
);
613 if (!s
->sftp_handle
) {
614 session_error_setg(errp
, s
, "failed to open remote file '%s'", path
);
619 r
= libssh2_sftp_fstat(s
->sftp_handle
, &s
->attrs
);
621 sftp_error_setg(errp
, s
, "failed to read file attributes");
625 /* Delete the options we've used; any not deleted will cause the
626 * block layer to give an error about unused options.
628 qdict_del(options
, "host");
629 qdict_del(options
, "port");
630 qdict_del(options
, "user");
631 qdict_del(options
, "path");
632 qdict_del(options
, "host_key_check");
637 if (s
->sftp_handle
) {
638 libssh2_sftp_close(s
->sftp_handle
);
640 s
->sftp_handle
= NULL
;
642 libssh2_sftp_shutdown(s
->sftp
);
646 libssh2_session_disconnect(s
->session
,
647 "from qemu ssh client: "
648 "error opening connection");
649 libssh2_session_free(s
->session
);
656 static int ssh_file_open(BlockDriverState
*bs
, QDict
*options
, int bdrv_flags
,
659 BDRVSSHState
*s
= bs
->opaque
;
665 ssh_flags
= LIBSSH2_FXF_READ
;
666 if (bdrv_flags
& BDRV_O_RDWR
) {
667 ssh_flags
|= LIBSSH2_FXF_WRITE
;
671 ret
= connect_to_ssh(s
, options
, ssh_flags
, 0, errp
);
676 /* Go non-blocking. */
677 libssh2_session_set_blocking(s
->session
, 0);
690 static QemuOptsList ssh_create_opts
= {
691 .name
= "ssh-create-opts",
692 .head
= QTAILQ_HEAD_INITIALIZER(ssh_create_opts
.head
),
695 .name
= BLOCK_OPT_SIZE
,
696 .type
= QEMU_OPT_SIZE
,
697 .help
= "Virtual disk size"
699 { /* end of list */ }
703 static int ssh_create(const char *filename
, QemuOpts
*opts
, Error
**errp
)
706 int64_t total_size
= 0;
707 QDict
*uri_options
= NULL
;
710 char c
[1] = { '\0' };
714 /* Get desired file size. */
715 total_size
= ROUND_UP(qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0),
717 DPRINTF("total_size=%" PRIi64
, total_size
);
719 uri_options
= qdict_new();
720 r
= parse_uri(filename
, uri_options
, errp
);
726 r
= connect_to_ssh(&s
, uri_options
,
727 LIBSSH2_FXF_READ
|LIBSSH2_FXF_WRITE
|
728 LIBSSH2_FXF_CREAT
|LIBSSH2_FXF_TRUNC
,
735 if (total_size
> 0) {
736 libssh2_sftp_seek64(s
.sftp_handle
, total_size
-1);
737 r2
= libssh2_sftp_write(s
.sftp_handle
, c
, 1);
739 sftp_error_setg(errp
, &s
, "truncate failed");
743 s
.attrs
.filesize
= total_size
;
750 if (uri_options
!= NULL
) {
751 QDECREF(uri_options
);
756 static void ssh_close(BlockDriverState
*bs
)
758 BDRVSSHState
*s
= bs
->opaque
;
763 static int ssh_has_zero_init(BlockDriverState
*bs
)
765 BDRVSSHState
*s
= bs
->opaque
;
766 /* Assume false, unless we can positively prove it's true. */
767 int has_zero_init
= 0;
769 if (s
->attrs
.flags
& LIBSSH2_SFTP_ATTR_PERMISSIONS
) {
770 if (s
->attrs
.permissions
& LIBSSH2_SFTP_S_IFREG
) {
775 return has_zero_init
;
778 static void restart_coroutine(void *opaque
)
780 Coroutine
*co
= opaque
;
782 DPRINTF("co=%p", co
);
784 qemu_coroutine_enter(co
, NULL
);
787 static coroutine_fn
void set_fd_handler(BDRVSSHState
*s
, BlockDriverState
*bs
)
790 IOHandler
*rd_handler
= NULL
, *wr_handler
= NULL
;
791 Coroutine
*co
= qemu_coroutine_self();
793 r
= libssh2_session_block_directions(s
->session
);
795 if (r
& LIBSSH2_SESSION_BLOCK_INBOUND
) {
796 rd_handler
= restart_coroutine
;
798 if (r
& LIBSSH2_SESSION_BLOCK_OUTBOUND
) {
799 wr_handler
= restart_coroutine
;
802 DPRINTF("s->sock=%d rd_handler=%p wr_handler=%p", s
->sock
,
803 rd_handler
, wr_handler
);
805 aio_set_fd_handler(bdrv_get_aio_context(bs
), s
->sock
,
806 rd_handler
, wr_handler
, co
);
809 static coroutine_fn
void clear_fd_handler(BDRVSSHState
*s
,
810 BlockDriverState
*bs
)
812 DPRINTF("s->sock=%d", s
->sock
);
813 aio_set_fd_handler(bdrv_get_aio_context(bs
), s
->sock
, NULL
, NULL
, NULL
);
816 /* A non-blocking call returned EAGAIN, so yield, ensuring the
817 * handlers are set up so that we'll be rescheduled when there is an
818 * interesting event on the socket.
820 static coroutine_fn
void co_yield(BDRVSSHState
*s
, BlockDriverState
*bs
)
822 set_fd_handler(s
, bs
);
823 qemu_coroutine_yield();
824 clear_fd_handler(s
, bs
);
827 /* SFTP has a function `libssh2_sftp_seek64' which seeks to a position
828 * in the remote file. Notice that it just updates a field in the
829 * sftp_handle structure, so there is no network traffic and it cannot
832 * However, `libssh2_sftp_seek64' does have a catastrophic effect on
833 * performance since it causes the handle to throw away all in-flight
834 * reads and buffered readahead data. Therefore this function tries
835 * to be intelligent about when to call the underlying libssh2 function.
837 #define SSH_SEEK_WRITE 0
838 #define SSH_SEEK_READ 1
839 #define SSH_SEEK_FORCE 2
841 static void ssh_seek(BDRVSSHState
*s
, int64_t offset
, int flags
)
843 bool op_read
= (flags
& SSH_SEEK_READ
) != 0;
844 bool force
= (flags
& SSH_SEEK_FORCE
) != 0;
846 if (force
|| op_read
!= s
->offset_op_read
|| offset
!= s
->offset
) {
847 DPRINTF("seeking to offset=%" PRIi64
, offset
);
848 libssh2_sftp_seek64(s
->sftp_handle
, offset
);
850 s
->offset_op_read
= op_read
;
854 static coroutine_fn
int ssh_read(BDRVSSHState
*s
, BlockDriverState
*bs
,
855 int64_t offset
, size_t size
,
860 char *buf
, *end_of_vec
;
863 DPRINTF("offset=%" PRIi64
" size=%zu", offset
, size
);
865 ssh_seek(s
, offset
, SSH_SEEK_READ
);
867 /* This keeps track of the current iovec element ('i'), where we
868 * will write to next ('buf'), and the end of the current iovec
873 end_of_vec
= i
->iov_base
+ i
->iov_len
;
875 /* libssh2 has a hard-coded limit of 2000 bytes per request,
876 * although it will also do readahead behind our backs. Therefore
877 * we may have to do repeated reads here until we have read 'size'
880 for (got
= 0; got
< size
; ) {
882 DPRINTF("sftp_read buf=%p size=%zu", buf
, end_of_vec
- buf
);
883 r
= libssh2_sftp_read(s
->sftp_handle
, buf
, end_of_vec
- buf
);
884 DPRINTF("sftp_read returned %zd", r
);
886 if (r
== LIBSSH2_ERROR_EAGAIN
|| r
== LIBSSH2_ERROR_TIMEOUT
) {
891 sftp_error_report(s
, "read failed");
896 /* EOF: Short read so pad the buffer with zeroes and return it. */
897 qemu_iovec_memset(qiov
, got
, 0, size
- got
);
904 if (buf
>= end_of_vec
&& got
< size
) {
907 end_of_vec
= i
->iov_base
+ i
->iov_len
;
914 static coroutine_fn
int ssh_co_readv(BlockDriverState
*bs
,
916 int nb_sectors
, QEMUIOVector
*qiov
)
918 BDRVSSHState
*s
= bs
->opaque
;
921 qemu_co_mutex_lock(&s
->lock
);
922 ret
= ssh_read(s
, bs
, sector_num
* BDRV_SECTOR_SIZE
,
923 nb_sectors
* BDRV_SECTOR_SIZE
, qiov
);
924 qemu_co_mutex_unlock(&s
->lock
);
929 static int ssh_write(BDRVSSHState
*s
, BlockDriverState
*bs
,
930 int64_t offset
, size_t size
,
935 char *buf
, *end_of_vec
;
938 DPRINTF("offset=%" PRIi64
" size=%zu", offset
, size
);
940 ssh_seek(s
, offset
, SSH_SEEK_WRITE
);
942 /* This keeps track of the current iovec element ('i'), where we
943 * will read from next ('buf'), and the end of the current iovec
948 end_of_vec
= i
->iov_base
+ i
->iov_len
;
950 for (written
= 0; written
< size
; ) {
952 DPRINTF("sftp_write buf=%p size=%zu", buf
, end_of_vec
- buf
);
953 r
= libssh2_sftp_write(s
->sftp_handle
, buf
, end_of_vec
- buf
);
954 DPRINTF("sftp_write returned %zd", r
);
956 if (r
== LIBSSH2_ERROR_EAGAIN
|| r
== LIBSSH2_ERROR_TIMEOUT
) {
961 sftp_error_report(s
, "write failed");
965 /* The libssh2 API is very unclear about this. A comment in
966 * the code says "nothing was acked, and no EAGAIN was
967 * received!" which apparently means that no data got sent
968 * out, and the underlying channel didn't return any EAGAIN
969 * indication. I think this is a bug in either libssh2 or
970 * OpenSSH (server-side). In any case, forcing a seek (to
971 * discard libssh2 internal buffers), and then trying again
975 ssh_seek(s
, offset
+ written
, SSH_SEEK_WRITE
|SSH_SEEK_FORCE
);
983 if (buf
>= end_of_vec
&& written
< size
) {
986 end_of_vec
= i
->iov_base
+ i
->iov_len
;
989 if (offset
+ written
> s
->attrs
.filesize
)
990 s
->attrs
.filesize
= offset
+ written
;
996 static coroutine_fn
int ssh_co_writev(BlockDriverState
*bs
,
998 int nb_sectors
, QEMUIOVector
*qiov
)
1000 BDRVSSHState
*s
= bs
->opaque
;
1003 qemu_co_mutex_lock(&s
->lock
);
1004 ret
= ssh_write(s
, bs
, sector_num
* BDRV_SECTOR_SIZE
,
1005 nb_sectors
* BDRV_SECTOR_SIZE
, qiov
);
1006 qemu_co_mutex_unlock(&s
->lock
);
1011 static void unsafe_flush_warning(BDRVSSHState
*s
, const char *what
)
1013 if (!s
->unsafe_flush_warning
) {
1014 error_report("warning: ssh server %s does not support fsync",
1017 error_report("to support fsync, you need %s", what
);
1019 s
->unsafe_flush_warning
= true;
1023 #ifdef HAS_LIBSSH2_SFTP_FSYNC
1025 static coroutine_fn
int ssh_flush(BDRVSSHState
*s
, BlockDriverState
*bs
)
1031 r
= libssh2_sftp_fsync(s
->sftp_handle
);
1032 if (r
== LIBSSH2_ERROR_EAGAIN
|| r
== LIBSSH2_ERROR_TIMEOUT
) {
1036 if (r
== LIBSSH2_ERROR_SFTP_PROTOCOL
&&
1037 libssh2_sftp_last_error(s
->sftp
) == LIBSSH2_FX_OP_UNSUPPORTED
) {
1038 unsafe_flush_warning(s
, "OpenSSH >= 6.3");
1042 sftp_error_report(s
, "fsync failed");
1049 static coroutine_fn
int ssh_co_flush(BlockDriverState
*bs
)
1051 BDRVSSHState
*s
= bs
->opaque
;
1054 qemu_co_mutex_lock(&s
->lock
);
1055 ret
= ssh_flush(s
, bs
);
1056 qemu_co_mutex_unlock(&s
->lock
);
1061 #else /* !HAS_LIBSSH2_SFTP_FSYNC */
1063 static coroutine_fn
int ssh_co_flush(BlockDriverState
*bs
)
1065 BDRVSSHState
*s
= bs
->opaque
;
1067 unsafe_flush_warning(s
, "libssh2 >= 1.4.4");
1071 #endif /* !HAS_LIBSSH2_SFTP_FSYNC */
1073 static int64_t ssh_getlength(BlockDriverState
*bs
)
1075 BDRVSSHState
*s
= bs
->opaque
;
1078 /* Note we cannot make a libssh2 call here. */
1079 length
= (int64_t) s
->attrs
.filesize
;
1080 DPRINTF("length=%" PRIi64
, length
);
1085 static BlockDriver bdrv_ssh
= {
1086 .format_name
= "ssh",
1087 .protocol_name
= "ssh",
1088 .instance_size
= sizeof(BDRVSSHState
),
1089 .bdrv_parse_filename
= ssh_parse_filename
,
1090 .bdrv_file_open
= ssh_file_open
,
1091 .bdrv_create
= ssh_create
,
1092 .bdrv_close
= ssh_close
,
1093 .bdrv_has_zero_init
= ssh_has_zero_init
,
1094 .bdrv_co_readv
= ssh_co_readv
,
1095 .bdrv_co_writev
= ssh_co_writev
,
1096 .bdrv_getlength
= ssh_getlength
,
1097 .bdrv_co_flush_to_disk
= ssh_co_flush
,
1098 .create_opts
= &ssh_create_opts
,
1101 static void bdrv_ssh_init(void)
1105 r
= libssh2_init(0);
1107 fprintf(stderr
, "libssh2 initialization failed, %d\n", r
);
1111 bdrv_register(&bdrv_ssh
);
1114 block_init(bdrv_ssh_init
);