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
25 #include "qemu/osdep.h"
28 #include <libssh2_sftp.h>
30 #include "block/block_int.h"
31 #include "qapi/error.h"
32 #include "qemu/error-report.h"
33 #include "qemu/cutils.h"
34 #include "qemu/sockets.h"
36 #include "qapi-visit.h"
37 #include "qapi/qmp/qstring.h"
38 #include "qapi/qobject-input-visitor.h"
39 #include "qapi/qobject-output-visitor.h"
41 /* DEBUG_SSH=1 enables the DPRINTF (debugging printf) statements in
42 * this block driver code.
44 * TRACE_LIBSSH2=<bitmask> enables tracing in libssh2 itself. Note
45 * that this requires that libssh2 was specially compiled with the
46 * `./configure --enable-debug' option, so most likely you will have
47 * to compile it yourself. The meaning of <bitmask> is described
48 * here: http://www.libssh2.org/libssh2_trace.html
51 #define TRACE_LIBSSH2 0 /* or try: LIBSSH2_TRACE_SFTP */
53 #define DPRINTF(fmt, ...) \
56 fprintf(stderr, "ssh: %-15s " fmt "\n", \
57 __func__, ##__VA_ARGS__); \
61 typedef struct BDRVSSHState
{
66 int sock
; /* socket */
67 LIBSSH2_SESSION
*session
; /* ssh session */
68 LIBSSH2_SFTP
*sftp
; /* sftp session */
69 LIBSSH2_SFTP_HANDLE
*sftp_handle
; /* sftp remote file handle */
71 /* See ssh_seek() function below. */
75 /* File attributes at open. We try to keep the .filesize field
76 * updated if it changes (eg by writing at the end of the file).
78 LIBSSH2_SFTP_ATTRIBUTES attrs
;
80 InetSocketAddress
*inet
;
82 /* Used to warn if 'flush' is not supported. */
83 bool unsafe_flush_warning
;
86 static void ssh_state_init(BDRVSSHState
*s
)
88 memset(s
, 0, sizeof *s
);
91 qemu_co_mutex_init(&s
->lock
);
94 static void ssh_state_free(BDRVSSHState
*s
)
97 libssh2_sftp_close(s
->sftp_handle
);
100 libssh2_sftp_shutdown(s
->sftp
);
103 libssh2_session_disconnect(s
->session
,
104 "from qemu ssh client: "
105 "user closed the connection");
106 libssh2_session_free(s
->session
);
113 static void GCC_FMT_ATTR(3, 4)
114 session_error_setg(Error
**errp
, BDRVSSHState
*s
, const char *fs
, ...)
120 msg
= g_strdup_vprintf(fs
, args
);
127 /* This is not an errno. See <libssh2.h>. */
128 ssh_err_code
= libssh2_session_last_error(s
->session
,
130 error_setg(errp
, "%s: %s (libssh2 error code: %d)",
131 msg
, ssh_err
, ssh_err_code
);
133 error_setg(errp
, "%s", msg
);
138 static void GCC_FMT_ATTR(3, 4)
139 sftp_error_setg(Error
**errp
, BDRVSSHState
*s
, const char *fs
, ...)
145 msg
= g_strdup_vprintf(fs
, args
);
151 unsigned long sftp_err_code
;
153 /* This is not an errno. See <libssh2.h>. */
154 ssh_err_code
= libssh2_session_last_error(s
->session
,
156 /* See <libssh2_sftp.h>. */
157 sftp_err_code
= libssh2_sftp_last_error((s
)->sftp
);
160 "%s: %s (libssh2 error code: %d, sftp error code: %lu)",
161 msg
, ssh_err
, ssh_err_code
, sftp_err_code
);
163 error_setg(errp
, "%s", msg
);
168 static void GCC_FMT_ATTR(2, 3)
169 sftp_error_report(BDRVSSHState
*s
, const char *fs
, ...)
174 error_vprintf(fs
, args
);
179 unsigned long sftp_err_code
;
181 /* This is not an errno. See <libssh2.h>. */
182 ssh_err_code
= libssh2_session_last_error(s
->session
,
184 /* See <libssh2_sftp.h>. */
185 sftp_err_code
= libssh2_sftp_last_error((s
)->sftp
);
187 error_printf(": %s (libssh2 error code: %d, sftp error code: %lu)",
188 ssh_err
, ssh_err_code
, sftp_err_code
);
195 static int parse_uri(const char *filename
, QDict
*options
, Error
**errp
)
202 uri
= uri_parse(filename
);
207 if (strcmp(uri
->scheme
, "ssh") != 0) {
208 error_setg(errp
, "URI scheme must be 'ssh'");
212 if (!uri
->server
|| strcmp(uri
->server
, "") == 0) {
213 error_setg(errp
, "missing hostname in URI");
217 if (!uri
->path
|| strcmp(uri
->path
, "") == 0) {
218 error_setg(errp
, "missing remote path in URI");
222 qp
= query_params_parse(uri
->query
);
224 error_setg(errp
, "could not parse query parameters");
228 if(uri
->user
&& strcmp(uri
->user
, "") != 0) {
229 qdict_put_str(options
, "user", uri
->user
);
232 qdict_put_str(options
, "server.host", uri
->server
);
234 port_str
= g_strdup_printf("%d", uri
->port
?: 22);
235 qdict_put_str(options
, "server.port", port_str
);
238 qdict_put_str(options
, "path", uri
->path
);
240 /* Pick out any query parameters that we understand, and ignore
243 for (i
= 0; i
< qp
->n
; ++i
) {
244 if (strcmp(qp
->p
[i
].name
, "host_key_check") == 0) {
245 qdict_put_str(options
, "host_key_check", qp
->p
[i
].value
);
249 query_params_free(qp
);
260 static bool ssh_has_filename_options_conflict(QDict
*options
, Error
**errp
)
262 const QDictEntry
*qe
;
264 for (qe
= qdict_first(options
); qe
; qe
= qdict_next(options
, qe
)) {
265 if (!strcmp(qe
->key
, "host") ||
266 !strcmp(qe
->key
, "port") ||
267 !strcmp(qe
->key
, "path") ||
268 !strcmp(qe
->key
, "user") ||
269 !strcmp(qe
->key
, "host_key_check") ||
270 strstart(qe
->key
, "server.", NULL
))
272 error_setg(errp
, "Option '%s' cannot be used with a file name",
281 static void ssh_parse_filename(const char *filename
, QDict
*options
,
284 if (ssh_has_filename_options_conflict(options
, errp
)) {
288 parse_uri(filename
, options
, errp
);
291 static int check_host_key_knownhosts(BDRVSSHState
*s
,
292 const char *host
, int port
, Error
**errp
)
295 char *knh_file
= NULL
;
296 LIBSSH2_KNOWNHOSTS
*knh
= NULL
;
297 struct libssh2_knownhost
*found
;
303 hostkey
= libssh2_session_hostkey(s
->session
, &len
, &type
);
306 session_error_setg(errp
, s
, "failed to read remote host key");
310 knh
= libssh2_knownhost_init(s
->session
);
313 session_error_setg(errp
, s
,
314 "failed to initialize known hosts support");
318 home
= getenv("HOME");
320 knh_file
= g_strdup_printf("%s/.ssh/known_hosts", home
);
322 knh_file
= g_strdup_printf("/root/.ssh/known_hosts");
325 /* Read all known hosts from OpenSSH-style known_hosts file. */
326 libssh2_knownhost_readfile(knh
, knh_file
, LIBSSH2_KNOWNHOST_FILE_OPENSSH
);
328 r
= libssh2_knownhost_checkp(knh
, host
, port
, hostkey
, len
,
329 LIBSSH2_KNOWNHOST_TYPE_PLAIN
|
330 LIBSSH2_KNOWNHOST_KEYENC_RAW
,
333 case LIBSSH2_KNOWNHOST_CHECK_MATCH
:
335 DPRINTF("host key OK: %s", found
->key
);
337 case LIBSSH2_KNOWNHOST_CHECK_MISMATCH
:
339 session_error_setg(errp
, s
,
340 "host key does not match the one in known_hosts"
341 " (found key %s)", found
->key
);
343 case LIBSSH2_KNOWNHOST_CHECK_NOTFOUND
:
345 session_error_setg(errp
, s
, "no host key was found in known_hosts");
347 case LIBSSH2_KNOWNHOST_CHECK_FAILURE
:
349 session_error_setg(errp
, s
,
350 "failure matching the host key with known_hosts");
354 session_error_setg(errp
, s
, "unknown error matching the host key"
355 " with known_hosts (%d)", r
);
359 /* known_hosts checking successful. */
364 libssh2_knownhost_free(knh
);
370 static unsigned hex2decimal(char ch
)
372 if (ch
>= '0' && ch
<= '9') {
374 } else if (ch
>= 'a' && ch
<= 'f') {
375 return 10 + (ch
- 'a');
376 } else if (ch
>= 'A' && ch
<= 'F') {
377 return 10 + (ch
- 'A');
383 /* Compare the binary fingerprint (hash of host key) with the
384 * host_key_check parameter.
386 static int compare_fingerprint(const unsigned char *fingerprint
, size_t len
,
387 const char *host_key_check
)
392 while (*host_key_check
== ':')
394 if (!qemu_isxdigit(host_key_check
[0]) ||
395 !qemu_isxdigit(host_key_check
[1]))
397 c
= hex2decimal(host_key_check
[0]) * 16 +
398 hex2decimal(host_key_check
[1]);
399 if (c
- *fingerprint
!= 0)
400 return c
- *fingerprint
;
405 return *host_key_check
- '\0';
409 check_host_key_hash(BDRVSSHState
*s
, const char *hash
,
410 int hash_type
, size_t fingerprint_len
, Error
**errp
)
412 const char *fingerprint
;
414 fingerprint
= libssh2_hostkey_hash(s
->session
, hash_type
);
416 session_error_setg(errp
, s
, "failed to read remote host key");
420 if(compare_fingerprint((unsigned char *) fingerprint
, fingerprint_len
,
422 error_setg(errp
, "remote host key does not match host_key_check '%s'",
430 static int check_host_key(BDRVSSHState
*s
, const char *host
, int port
,
431 const char *host_key_check
, Error
**errp
)
433 /* host_key_check=no */
434 if (strcmp(host_key_check
, "no") == 0) {
438 /* host_key_check=md5:xx:yy:zz:... */
439 if (strncmp(host_key_check
, "md5:", 4) == 0) {
440 return check_host_key_hash(s
, &host_key_check
[4],
441 LIBSSH2_HOSTKEY_HASH_MD5
, 16, errp
);
444 /* host_key_check=sha1:xx:yy:zz:... */
445 if (strncmp(host_key_check
, "sha1:", 5) == 0) {
446 return check_host_key_hash(s
, &host_key_check
[5],
447 LIBSSH2_HOSTKEY_HASH_SHA1
, 20, errp
);
450 /* host_key_check=yes */
451 if (strcmp(host_key_check
, "yes") == 0) {
452 return check_host_key_knownhosts(s
, host
, port
, errp
);
455 error_setg(errp
, "unknown host_key_check setting (%s)", host_key_check
);
459 static int authenticate(BDRVSSHState
*s
, const char *user
, Error
**errp
)
462 const char *userauthlist
;
463 LIBSSH2_AGENT
*agent
= NULL
;
464 struct libssh2_agent_publickey
*identity
;
465 struct libssh2_agent_publickey
*prev_identity
= NULL
;
467 userauthlist
= libssh2_userauth_list(s
->session
, user
, strlen(user
));
468 if (strstr(userauthlist
, "publickey") == NULL
) {
471 "remote server does not support \"publickey\" authentication");
475 /* Connect to ssh-agent and try each identity in turn. */
476 agent
= libssh2_agent_init(s
->session
);
479 session_error_setg(errp
, s
, "failed to initialize ssh-agent support");
482 if (libssh2_agent_connect(agent
)) {
484 session_error_setg(errp
, s
, "failed to connect to ssh-agent");
487 if (libssh2_agent_list_identities(agent
)) {
489 session_error_setg(errp
, s
,
490 "failed requesting identities from ssh-agent");
495 r
= libssh2_agent_get_identity(agent
, &identity
, prev_identity
);
496 if (r
== 1) { /* end of list */
501 session_error_setg(errp
, s
,
502 "failed to obtain identity from ssh-agent");
505 r
= libssh2_agent_userauth(agent
, user
, identity
);
511 /* Failed to authenticate with this identity, try the next one. */
512 prev_identity
= identity
;
516 error_setg(errp
, "failed to authenticate using publickey authentication "
517 "and the identities held by your ssh-agent");
521 /* Note: libssh2 implementation implicitly calls
522 * libssh2_agent_disconnect if necessary.
524 libssh2_agent_free(agent
);
530 static QemuOptsList ssh_runtime_opts
= {
532 .head
= QTAILQ_HEAD_INITIALIZER(ssh_runtime_opts
.head
),
536 .type
= QEMU_OPT_STRING
,
537 .help
= "Host to connect to",
541 .type
= QEMU_OPT_NUMBER
,
542 .help
= "Port to connect to",
546 .type
= QEMU_OPT_STRING
,
547 .help
= "Path of the image on the host",
551 .type
= QEMU_OPT_STRING
,
552 .help
= "User as which to connect",
555 .name
= "host_key_check",
556 .type
= QEMU_OPT_STRING
,
557 .help
= "Defines how and what to check the host key against",
562 static bool ssh_process_legacy_socket_options(QDict
*output_opts
,
563 QemuOpts
*legacy_opts
,
566 const char *host
= qemu_opt_get(legacy_opts
, "host");
567 const char *port
= qemu_opt_get(legacy_opts
, "port");
570 error_setg(errp
, "port may not be used without host");
575 qdict_put_str(output_opts
, "server.host", host
);
576 qdict_put_str(output_opts
, "server.port", port
?: stringify(22));
582 static InetSocketAddress
*ssh_config(QDict
*options
, Error
**errp
)
584 InetSocketAddress
*inet
= NULL
;
586 QObject
*crumpled_addr
= NULL
;
588 Error
*local_error
= NULL
;
590 qdict_extract_subqdict(options
, &addr
, "server.");
591 if (!qdict_size(addr
)) {
592 error_setg(errp
, "SSH server address missing");
596 crumpled_addr
= qdict_crumple(addr
, errp
);
597 if (!crumpled_addr
) {
602 * FIXME .numeric, .to, .ipv4 or .ipv6 don't work with -drive.
603 * .to doesn't matter, it's ignored anyway.
604 * That's because when @options come from -blockdev or
605 * blockdev_add, members are typed according to the QAPI schema,
606 * but when they come from -drive, they're all QString. The
607 * visitor expects the former.
609 iv
= qobject_input_visitor_new(crumpled_addr
);
610 visit_type_InetSocketAddress(iv
, NULL
, &inet
, &local_error
);
612 error_propagate(errp
, local_error
);
618 qobject_decref(crumpled_addr
);
623 static int connect_to_ssh(BDRVSSHState
*s
, QDict
*options
,
624 int ssh_flags
, int creat_mode
, Error
**errp
)
627 QemuOpts
*opts
= NULL
;
628 Error
*local_err
= NULL
;
629 const char *user
, *path
, *host_key_check
;
632 opts
= qemu_opts_create(&ssh_runtime_opts
, NULL
, 0, &error_abort
);
633 qemu_opts_absorb_qdict(opts
, options
, &local_err
);
636 error_propagate(errp
, local_err
);
640 if (!ssh_process_legacy_socket_options(options
, opts
, errp
)) {
645 path
= qemu_opt_get(opts
, "path");
648 error_setg(errp
, "No path was specified");
652 user
= qemu_opt_get(opts
, "user");
654 user
= g_get_user_name();
656 error_setg_errno(errp
, errno
, "Can't get user name");
662 host_key_check
= qemu_opt_get(opts
, "host_key_check");
663 if (!host_key_check
) {
664 host_key_check
= "yes";
667 /* Pop the config into our state object, Exit if invalid */
668 s
->inet
= ssh_config(options
, errp
);
674 if (qemu_strtol(s
->inet
->port
, NULL
, 10, &port
) < 0) {
675 error_setg(errp
, "Use only numeric port value");
680 /* Open the socket and connect. */
681 s
->sock
= inet_connect_saddr(s
->inet
, NULL
, NULL
, errp
);
687 /* Create SSH session. */
688 s
->session
= libssh2_session_init();
691 session_error_setg(errp
, s
, "failed to initialize libssh2 session");
695 #if TRACE_LIBSSH2 != 0
696 libssh2_trace(s
->session
, TRACE_LIBSSH2
);
699 r
= libssh2_session_handshake(s
->session
, s
->sock
);
702 session_error_setg(errp
, s
, "failed to establish SSH session");
706 /* Check the remote host's key against known_hosts. */
707 ret
= check_host_key(s
, s
->inet
->host
, port
, host_key_check
,
714 ret
= authenticate(s
, user
, errp
);
720 s
->sftp
= libssh2_sftp_init(s
->session
);
722 session_error_setg(errp
, s
, "failed to initialize sftp handle");
727 /* Open the remote file. */
728 DPRINTF("opening file %s flags=0x%x creat_mode=0%o",
729 path
, ssh_flags
, creat_mode
);
730 s
->sftp_handle
= libssh2_sftp_open(s
->sftp
, path
, ssh_flags
, creat_mode
);
731 if (!s
->sftp_handle
) {
732 session_error_setg(errp
, s
, "failed to open remote file '%s'", path
);
739 r
= libssh2_sftp_fstat(s
->sftp_handle
, &s
->attrs
);
741 sftp_error_setg(errp
, s
, "failed to read file attributes");
748 if (s
->sftp_handle
) {
749 libssh2_sftp_close(s
->sftp_handle
);
751 s
->sftp_handle
= NULL
;
753 libssh2_sftp_shutdown(s
->sftp
);
757 libssh2_session_disconnect(s
->session
,
758 "from qemu ssh client: "
759 "error opening connection");
760 libssh2_session_free(s
->session
);
769 static int ssh_file_open(BlockDriverState
*bs
, QDict
*options
, int bdrv_flags
,
772 BDRVSSHState
*s
= bs
->opaque
;
778 ssh_flags
= LIBSSH2_FXF_READ
;
779 if (bdrv_flags
& BDRV_O_RDWR
) {
780 ssh_flags
|= LIBSSH2_FXF_WRITE
;
784 ret
= connect_to_ssh(s
, options
, ssh_flags
, 0, errp
);
789 /* Go non-blocking. */
790 libssh2_session_set_blocking(s
->session
, 0);
803 static QemuOptsList ssh_create_opts
= {
804 .name
= "ssh-create-opts",
805 .head
= QTAILQ_HEAD_INITIALIZER(ssh_create_opts
.head
),
808 .name
= BLOCK_OPT_SIZE
,
809 .type
= QEMU_OPT_SIZE
,
810 .help
= "Virtual disk size"
812 { /* end of list */ }
816 static int ssh_create(const char *filename
, QemuOpts
*opts
, Error
**errp
)
819 int64_t total_size
= 0;
820 QDict
*uri_options
= NULL
;
823 char c
[1] = { '\0' };
827 /* Get desired file size. */
828 total_size
= ROUND_UP(qemu_opt_get_size_del(opts
, BLOCK_OPT_SIZE
, 0),
830 DPRINTF("total_size=%" PRIi64
, total_size
);
832 uri_options
= qdict_new();
833 r
= parse_uri(filename
, uri_options
, errp
);
839 r
= connect_to_ssh(&s
, uri_options
,
840 LIBSSH2_FXF_READ
|LIBSSH2_FXF_WRITE
|
841 LIBSSH2_FXF_CREAT
|LIBSSH2_FXF_TRUNC
,
848 if (total_size
> 0) {
849 libssh2_sftp_seek64(s
.sftp_handle
, total_size
-1);
850 r2
= libssh2_sftp_write(s
.sftp_handle
, c
, 1);
852 sftp_error_setg(errp
, &s
, "truncate failed");
856 s
.attrs
.filesize
= total_size
;
863 if (uri_options
!= NULL
) {
864 QDECREF(uri_options
);
869 static void ssh_close(BlockDriverState
*bs
)
871 BDRVSSHState
*s
= bs
->opaque
;
876 static int ssh_has_zero_init(BlockDriverState
*bs
)
878 BDRVSSHState
*s
= bs
->opaque
;
879 /* Assume false, unless we can positively prove it's true. */
880 int has_zero_init
= 0;
882 if (s
->attrs
.flags
& LIBSSH2_SFTP_ATTR_PERMISSIONS
) {
883 if (s
->attrs
.permissions
& LIBSSH2_SFTP_S_IFREG
) {
888 return has_zero_init
;
891 static void restart_coroutine(void *opaque
)
893 Coroutine
*co
= opaque
;
895 DPRINTF("co=%p", co
);
900 /* A non-blocking call returned EAGAIN, so yield, ensuring the
901 * handlers are set up so that we'll be rescheduled when there is an
902 * interesting event on the socket.
904 static coroutine_fn
void co_yield(BDRVSSHState
*s
, BlockDriverState
*bs
)
907 IOHandler
*rd_handler
= NULL
, *wr_handler
= NULL
;
908 Coroutine
*co
= qemu_coroutine_self();
910 r
= libssh2_session_block_directions(s
->session
);
912 if (r
& LIBSSH2_SESSION_BLOCK_INBOUND
) {
913 rd_handler
= restart_coroutine
;
915 if (r
& LIBSSH2_SESSION_BLOCK_OUTBOUND
) {
916 wr_handler
= restart_coroutine
;
919 DPRINTF("s->sock=%d rd_handler=%p wr_handler=%p", s
->sock
,
920 rd_handler
, wr_handler
);
922 aio_set_fd_handler(bdrv_get_aio_context(bs
), s
->sock
,
923 false, rd_handler
, wr_handler
, NULL
, co
);
924 qemu_coroutine_yield();
925 DPRINTF("s->sock=%d - back", s
->sock
);
926 aio_set_fd_handler(bdrv_get_aio_context(bs
), s
->sock
, false,
927 NULL
, NULL
, NULL
, NULL
);
930 /* SFTP has a function `libssh2_sftp_seek64' which seeks to a position
931 * in the remote file. Notice that it just updates a field in the
932 * sftp_handle structure, so there is no network traffic and it cannot
935 * However, `libssh2_sftp_seek64' does have a catastrophic effect on
936 * performance since it causes the handle to throw away all in-flight
937 * reads and buffered readahead data. Therefore this function tries
938 * to be intelligent about when to call the underlying libssh2 function.
940 #define SSH_SEEK_WRITE 0
941 #define SSH_SEEK_READ 1
942 #define SSH_SEEK_FORCE 2
944 static void ssh_seek(BDRVSSHState
*s
, int64_t offset
, int flags
)
946 bool op_read
= (flags
& SSH_SEEK_READ
) != 0;
947 bool force
= (flags
& SSH_SEEK_FORCE
) != 0;
949 if (force
|| op_read
!= s
->offset_op_read
|| offset
!= s
->offset
) {
950 DPRINTF("seeking to offset=%" PRIi64
, offset
);
951 libssh2_sftp_seek64(s
->sftp_handle
, offset
);
953 s
->offset_op_read
= op_read
;
957 static coroutine_fn
int ssh_read(BDRVSSHState
*s
, BlockDriverState
*bs
,
958 int64_t offset
, size_t size
,
963 char *buf
, *end_of_vec
;
966 DPRINTF("offset=%" PRIi64
" size=%zu", offset
, size
);
968 ssh_seek(s
, offset
, SSH_SEEK_READ
);
970 /* This keeps track of the current iovec element ('i'), where we
971 * will write to next ('buf'), and the end of the current iovec
976 end_of_vec
= i
->iov_base
+ i
->iov_len
;
978 /* libssh2 has a hard-coded limit of 2000 bytes per request,
979 * although it will also do readahead behind our backs. Therefore
980 * we may have to do repeated reads here until we have read 'size'
983 for (got
= 0; got
< size
; ) {
985 DPRINTF("sftp_read buf=%p size=%zu", buf
, end_of_vec
- buf
);
986 r
= libssh2_sftp_read(s
->sftp_handle
, buf
, end_of_vec
- buf
);
987 DPRINTF("sftp_read returned %zd", r
);
989 if (r
== LIBSSH2_ERROR_EAGAIN
|| r
== LIBSSH2_ERROR_TIMEOUT
) {
994 sftp_error_report(s
, "read failed");
999 /* EOF: Short read so pad the buffer with zeroes and return it. */
1000 qemu_iovec_memset(qiov
, got
, 0, size
- got
);
1007 if (buf
>= end_of_vec
&& got
< size
) {
1010 end_of_vec
= i
->iov_base
+ i
->iov_len
;
1017 static coroutine_fn
int ssh_co_readv(BlockDriverState
*bs
,
1019 int nb_sectors
, QEMUIOVector
*qiov
)
1021 BDRVSSHState
*s
= bs
->opaque
;
1024 qemu_co_mutex_lock(&s
->lock
);
1025 ret
= ssh_read(s
, bs
, sector_num
* BDRV_SECTOR_SIZE
,
1026 nb_sectors
* BDRV_SECTOR_SIZE
, qiov
);
1027 qemu_co_mutex_unlock(&s
->lock
);
1032 static int ssh_write(BDRVSSHState
*s
, BlockDriverState
*bs
,
1033 int64_t offset
, size_t size
,
1038 char *buf
, *end_of_vec
;
1041 DPRINTF("offset=%" PRIi64
" size=%zu", offset
, size
);
1043 ssh_seek(s
, offset
, SSH_SEEK_WRITE
);
1045 /* This keeps track of the current iovec element ('i'), where we
1046 * will read from next ('buf'), and the end of the current iovec
1051 end_of_vec
= i
->iov_base
+ i
->iov_len
;
1053 for (written
= 0; written
< size
; ) {
1055 DPRINTF("sftp_write buf=%p size=%zu", buf
, end_of_vec
- buf
);
1056 r
= libssh2_sftp_write(s
->sftp_handle
, buf
, end_of_vec
- buf
);
1057 DPRINTF("sftp_write returned %zd", r
);
1059 if (r
== LIBSSH2_ERROR_EAGAIN
|| r
== LIBSSH2_ERROR_TIMEOUT
) {
1064 sftp_error_report(s
, "write failed");
1068 /* The libssh2 API is very unclear about this. A comment in
1069 * the code says "nothing was acked, and no EAGAIN was
1070 * received!" which apparently means that no data got sent
1071 * out, and the underlying channel didn't return any EAGAIN
1072 * indication. I think this is a bug in either libssh2 or
1073 * OpenSSH (server-side). In any case, forcing a seek (to
1074 * discard libssh2 internal buffers), and then trying again
1078 ssh_seek(s
, offset
+ written
, SSH_SEEK_WRITE
|SSH_SEEK_FORCE
);
1086 if (buf
>= end_of_vec
&& written
< size
) {
1089 end_of_vec
= i
->iov_base
+ i
->iov_len
;
1092 if (offset
+ written
> s
->attrs
.filesize
)
1093 s
->attrs
.filesize
= offset
+ written
;
1099 static coroutine_fn
int ssh_co_writev(BlockDriverState
*bs
,
1101 int nb_sectors
, QEMUIOVector
*qiov
)
1103 BDRVSSHState
*s
= bs
->opaque
;
1106 qemu_co_mutex_lock(&s
->lock
);
1107 ret
= ssh_write(s
, bs
, sector_num
* BDRV_SECTOR_SIZE
,
1108 nb_sectors
* BDRV_SECTOR_SIZE
, qiov
);
1109 qemu_co_mutex_unlock(&s
->lock
);
1114 static void unsafe_flush_warning(BDRVSSHState
*s
, const char *what
)
1116 if (!s
->unsafe_flush_warning
) {
1117 error_report("warning: ssh server %s does not support fsync",
1120 error_report("to support fsync, you need %s", what
);
1122 s
->unsafe_flush_warning
= true;
1126 #ifdef HAS_LIBSSH2_SFTP_FSYNC
1128 static coroutine_fn
int ssh_flush(BDRVSSHState
*s
, BlockDriverState
*bs
)
1134 r
= libssh2_sftp_fsync(s
->sftp_handle
);
1135 if (r
== LIBSSH2_ERROR_EAGAIN
|| r
== LIBSSH2_ERROR_TIMEOUT
) {
1139 if (r
== LIBSSH2_ERROR_SFTP_PROTOCOL
&&
1140 libssh2_sftp_last_error(s
->sftp
) == LIBSSH2_FX_OP_UNSUPPORTED
) {
1141 unsafe_flush_warning(s
, "OpenSSH >= 6.3");
1145 sftp_error_report(s
, "fsync failed");
1152 static coroutine_fn
int ssh_co_flush(BlockDriverState
*bs
)
1154 BDRVSSHState
*s
= bs
->opaque
;
1157 qemu_co_mutex_lock(&s
->lock
);
1158 ret
= ssh_flush(s
, bs
);
1159 qemu_co_mutex_unlock(&s
->lock
);
1164 #else /* !HAS_LIBSSH2_SFTP_FSYNC */
1166 static coroutine_fn
int ssh_co_flush(BlockDriverState
*bs
)
1168 BDRVSSHState
*s
= bs
->opaque
;
1170 unsafe_flush_warning(s
, "libssh2 >= 1.4.4");
1174 #endif /* !HAS_LIBSSH2_SFTP_FSYNC */
1176 static int64_t ssh_getlength(BlockDriverState
*bs
)
1178 BDRVSSHState
*s
= bs
->opaque
;
1181 /* Note we cannot make a libssh2 call here. */
1182 length
= (int64_t) s
->attrs
.filesize
;
1183 DPRINTF("length=%" PRIi64
, length
);
1188 static BlockDriver bdrv_ssh
= {
1189 .format_name
= "ssh",
1190 .protocol_name
= "ssh",
1191 .instance_size
= sizeof(BDRVSSHState
),
1192 .bdrv_parse_filename
= ssh_parse_filename
,
1193 .bdrv_file_open
= ssh_file_open
,
1194 .bdrv_create
= ssh_create
,
1195 .bdrv_close
= ssh_close
,
1196 .bdrv_has_zero_init
= ssh_has_zero_init
,
1197 .bdrv_co_readv
= ssh_co_readv
,
1198 .bdrv_co_writev
= ssh_co_writev
,
1199 .bdrv_getlength
= ssh_getlength
,
1200 .bdrv_co_flush_to_disk
= ssh_co_flush
,
1201 .create_opts
= &ssh_create_opts
,
1204 static void bdrv_ssh_init(void)
1208 r
= libssh2_init(0);
1210 fprintf(stderr
, "libssh2 initialization failed, %d\n", r
);
1214 bdrv_register(&bdrv_ssh
);
1217 block_init(bdrv_ssh_init
);