ivshmem: Fix unplug of device "ivshmem-plain"
[qemu/armbru.git] / block / ssh.c
blob7fbc27abdfb91fff8ae5fa9432e022d3c1f79498
1 /*
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
22 * THE SOFTWARE.
25 #include "qemu/osdep.h"
27 #include <libssh2.h>
28 #include <libssh2_sftp.h>
30 #include "block/block_int.h"
31 #include "block/qdict.h"
32 #include "qapi/error.h"
33 #include "qemu/error-report.h"
34 #include "qemu/option.h"
35 #include "qemu/cutils.h"
36 #include "qemu/sockets.h"
37 #include "qemu/uri.h"
38 #include "qapi/qapi-visit-sockets.h"
39 #include "qapi/qapi-visit-block-core.h"
40 #include "qapi/qmp/qdict.h"
41 #include "qapi/qmp/qstring.h"
42 #include "qapi/qobject-input-visitor.h"
43 #include "qapi/qobject-output-visitor.h"
45 /* DEBUG_SSH=1 enables the DPRINTF (debugging printf) statements in
46 * this block driver code.
48 * TRACE_LIBSSH2=<bitmask> enables tracing in libssh2 itself. Note
49 * that this requires that libssh2 was specially compiled with the
50 * `./configure --enable-debug' option, so most likely you will have
51 * to compile it yourself. The meaning of <bitmask> is described
52 * here: http://www.libssh2.org/libssh2_trace.html
54 #define DEBUG_SSH 0
55 #define TRACE_LIBSSH2 0 /* or try: LIBSSH2_TRACE_SFTP */
57 #define DPRINTF(fmt, ...) \
58 do { \
59 if (DEBUG_SSH) { \
60 fprintf(stderr, "ssh: %-15s " fmt "\n", \
61 __func__, ##__VA_ARGS__); \
62 } \
63 } while (0)
65 typedef struct BDRVSSHState {
66 /* Coroutine. */
67 CoMutex lock;
69 /* SSH connection. */
70 int sock; /* socket */
71 LIBSSH2_SESSION *session; /* ssh session */
72 LIBSSH2_SFTP *sftp; /* sftp session */
73 LIBSSH2_SFTP_HANDLE *sftp_handle; /* sftp remote file handle */
75 /* See ssh_seek() function below. */
76 int64_t offset;
77 bool offset_op_read;
79 /* File attributes at open. We try to keep the .filesize field
80 * updated if it changes (eg by writing at the end of the file).
82 LIBSSH2_SFTP_ATTRIBUTES attrs;
84 InetSocketAddress *inet;
86 /* Used to warn if 'flush' is not supported. */
87 bool unsafe_flush_warning;
88 } BDRVSSHState;
90 static void ssh_state_init(BDRVSSHState *s)
92 memset(s, 0, sizeof *s);
93 s->sock = -1;
94 s->offset = -1;
95 qemu_co_mutex_init(&s->lock);
98 static void ssh_state_free(BDRVSSHState *s)
100 if (s->sftp_handle) {
101 libssh2_sftp_close(s->sftp_handle);
103 if (s->sftp) {
104 libssh2_sftp_shutdown(s->sftp);
106 if (s->session) {
107 libssh2_session_disconnect(s->session,
108 "from qemu ssh client: "
109 "user closed the connection");
110 libssh2_session_free(s->session);
112 if (s->sock >= 0) {
113 close(s->sock);
117 static void GCC_FMT_ATTR(3, 4)
118 session_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
120 va_list args;
121 char *msg;
123 va_start(args, fs);
124 msg = g_strdup_vprintf(fs, args);
125 va_end(args);
127 if (s->session) {
128 char *ssh_err;
129 int ssh_err_code;
131 /* This is not an errno. See <libssh2.h>. */
132 ssh_err_code = libssh2_session_last_error(s->session,
133 &ssh_err, NULL, 0);
134 error_setg(errp, "%s: %s (libssh2 error code: %d)",
135 msg, ssh_err, ssh_err_code);
136 } else {
137 error_setg(errp, "%s", msg);
139 g_free(msg);
142 static void GCC_FMT_ATTR(3, 4)
143 sftp_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
145 va_list args;
146 char *msg;
148 va_start(args, fs);
149 msg = g_strdup_vprintf(fs, args);
150 va_end(args);
152 if (s->sftp) {
153 char *ssh_err;
154 int ssh_err_code;
155 unsigned long sftp_err_code;
157 /* This is not an errno. See <libssh2.h>. */
158 ssh_err_code = libssh2_session_last_error(s->session,
159 &ssh_err, NULL, 0);
160 /* See <libssh2_sftp.h>. */
161 sftp_err_code = libssh2_sftp_last_error((s)->sftp);
163 error_setg(errp,
164 "%s: %s (libssh2 error code: %d, sftp error code: %lu)",
165 msg, ssh_err, ssh_err_code, sftp_err_code);
166 } else {
167 error_setg(errp, "%s", msg);
169 g_free(msg);
172 static void GCC_FMT_ATTR(2, 3)
173 sftp_error_report(BDRVSSHState *s, const char *fs, ...)
175 va_list args;
177 va_start(args, fs);
178 error_vprintf(fs, args);
180 if ((s)->sftp) {
181 char *ssh_err;
182 int ssh_err_code;
183 unsigned long sftp_err_code;
185 /* This is not an errno. See <libssh2.h>. */
186 ssh_err_code = libssh2_session_last_error(s->session,
187 &ssh_err, NULL, 0);
188 /* See <libssh2_sftp.h>. */
189 sftp_err_code = libssh2_sftp_last_error((s)->sftp);
191 error_printf(": %s (libssh2 error code: %d, sftp error code: %lu)",
192 ssh_err, ssh_err_code, sftp_err_code);
195 va_end(args);
196 error_printf("\n");
199 static int parse_uri(const char *filename, QDict *options, Error **errp)
201 URI *uri = NULL;
202 QueryParams *qp;
203 char *port_str;
204 int i;
206 uri = uri_parse(filename);
207 if (!uri) {
208 return -EINVAL;
211 if (g_strcmp0(uri->scheme, "ssh") != 0) {
212 error_setg(errp, "URI scheme must be 'ssh'");
213 goto err;
216 if (!uri->server || strcmp(uri->server, "") == 0) {
217 error_setg(errp, "missing hostname in URI");
218 goto err;
221 if (!uri->path || strcmp(uri->path, "") == 0) {
222 error_setg(errp, "missing remote path in URI");
223 goto err;
226 qp = query_params_parse(uri->query);
227 if (!qp) {
228 error_setg(errp, "could not parse query parameters");
229 goto err;
232 if(uri->user && strcmp(uri->user, "") != 0) {
233 qdict_put_str(options, "user", uri->user);
236 qdict_put_str(options, "server.host", uri->server);
238 port_str = g_strdup_printf("%d", uri->port ?: 22);
239 qdict_put_str(options, "server.port", port_str);
240 g_free(port_str);
242 qdict_put_str(options, "path", uri->path);
244 /* Pick out any query parameters that we understand, and ignore
245 * the rest.
247 for (i = 0; i < qp->n; ++i) {
248 if (strcmp(qp->p[i].name, "host_key_check") == 0) {
249 qdict_put_str(options, "host_key_check", qp->p[i].value);
253 query_params_free(qp);
254 uri_free(uri);
255 return 0;
257 err:
258 if (uri) {
259 uri_free(uri);
261 return -EINVAL;
264 static bool ssh_has_filename_options_conflict(QDict *options, Error **errp)
266 const QDictEntry *qe;
268 for (qe = qdict_first(options); qe; qe = qdict_next(options, qe)) {
269 if (!strcmp(qe->key, "host") ||
270 !strcmp(qe->key, "port") ||
271 !strcmp(qe->key, "path") ||
272 !strcmp(qe->key, "user") ||
273 !strcmp(qe->key, "host_key_check") ||
274 strstart(qe->key, "server.", NULL))
276 error_setg(errp, "Option '%s' cannot be used with a file name",
277 qe->key);
278 return true;
282 return false;
285 static void ssh_parse_filename(const char *filename, QDict *options,
286 Error **errp)
288 if (ssh_has_filename_options_conflict(options, errp)) {
289 return;
292 parse_uri(filename, options, errp);
295 static int check_host_key_knownhosts(BDRVSSHState *s,
296 const char *host, int port, Error **errp)
298 const char *home;
299 char *knh_file = NULL;
300 LIBSSH2_KNOWNHOSTS *knh = NULL;
301 struct libssh2_knownhost *found;
302 int ret, r;
303 const char *hostkey;
304 size_t len;
305 int type;
307 hostkey = libssh2_session_hostkey(s->session, &len, &type);
308 if (!hostkey) {
309 ret = -EINVAL;
310 session_error_setg(errp, s, "failed to read remote host key");
311 goto out;
314 knh = libssh2_knownhost_init(s->session);
315 if (!knh) {
316 ret = -EINVAL;
317 session_error_setg(errp, s,
318 "failed to initialize known hosts support");
319 goto out;
322 home = getenv("HOME");
323 if (home) {
324 knh_file = g_strdup_printf("%s/.ssh/known_hosts", home);
325 } else {
326 knh_file = g_strdup_printf("/root/.ssh/known_hosts");
329 /* Read all known hosts from OpenSSH-style known_hosts file. */
330 libssh2_knownhost_readfile(knh, knh_file, LIBSSH2_KNOWNHOST_FILE_OPENSSH);
332 r = libssh2_knownhost_checkp(knh, host, port, hostkey, len,
333 LIBSSH2_KNOWNHOST_TYPE_PLAIN|
334 LIBSSH2_KNOWNHOST_KEYENC_RAW,
335 &found);
336 switch (r) {
337 case LIBSSH2_KNOWNHOST_CHECK_MATCH:
338 /* OK */
339 DPRINTF("host key OK: %s", found->key);
340 break;
341 case LIBSSH2_KNOWNHOST_CHECK_MISMATCH:
342 ret = -EINVAL;
343 session_error_setg(errp, s,
344 "host key does not match the one in known_hosts"
345 " (found key %s)", found->key);
346 goto out;
347 case LIBSSH2_KNOWNHOST_CHECK_NOTFOUND:
348 ret = -EINVAL;
349 session_error_setg(errp, s, "no host key was found in known_hosts");
350 goto out;
351 case LIBSSH2_KNOWNHOST_CHECK_FAILURE:
352 ret = -EINVAL;
353 session_error_setg(errp, s,
354 "failure matching the host key with known_hosts");
355 goto out;
356 default:
357 ret = -EINVAL;
358 session_error_setg(errp, s, "unknown error matching the host key"
359 " with known_hosts (%d)", r);
360 goto out;
363 /* known_hosts checking successful. */
364 ret = 0;
366 out:
367 if (knh != NULL) {
368 libssh2_knownhost_free(knh);
370 g_free(knh_file);
371 return ret;
374 static unsigned hex2decimal(char ch)
376 if (ch >= '0' && ch <= '9') {
377 return (ch - '0');
378 } else if (ch >= 'a' && ch <= 'f') {
379 return 10 + (ch - 'a');
380 } else if (ch >= 'A' && ch <= 'F') {
381 return 10 + (ch - 'A');
384 return -1;
387 /* Compare the binary fingerprint (hash of host key) with the
388 * host_key_check parameter.
390 static int compare_fingerprint(const unsigned char *fingerprint, size_t len,
391 const char *host_key_check)
393 unsigned c;
395 while (len > 0) {
396 while (*host_key_check == ':')
397 host_key_check++;
398 if (!qemu_isxdigit(host_key_check[0]) ||
399 !qemu_isxdigit(host_key_check[1]))
400 return 1;
401 c = hex2decimal(host_key_check[0]) * 16 +
402 hex2decimal(host_key_check[1]);
403 if (c - *fingerprint != 0)
404 return c - *fingerprint;
405 fingerprint++;
406 len--;
407 host_key_check += 2;
409 return *host_key_check - '\0';
412 static int
413 check_host_key_hash(BDRVSSHState *s, const char *hash,
414 int hash_type, size_t fingerprint_len, Error **errp)
416 const char *fingerprint;
418 fingerprint = libssh2_hostkey_hash(s->session, hash_type);
419 if (!fingerprint) {
420 session_error_setg(errp, s, "failed to read remote host key");
421 return -EINVAL;
424 if(compare_fingerprint((unsigned char *) fingerprint, fingerprint_len,
425 hash) != 0) {
426 error_setg(errp, "remote host key does not match host_key_check '%s'",
427 hash);
428 return -EPERM;
431 return 0;
434 static int check_host_key(BDRVSSHState *s, const char *host, int port,
435 SshHostKeyCheck *hkc, Error **errp)
437 SshHostKeyCheckMode mode;
439 if (hkc) {
440 mode = hkc->mode;
441 } else {
442 mode = SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS;
445 switch (mode) {
446 case SSH_HOST_KEY_CHECK_MODE_NONE:
447 return 0;
448 case SSH_HOST_KEY_CHECK_MODE_HASH:
449 if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_MD5) {
450 return check_host_key_hash(s, hkc->u.hash.hash,
451 LIBSSH2_HOSTKEY_HASH_MD5, 16, errp);
452 } else if (hkc->u.hash.type == SSH_HOST_KEY_CHECK_HASH_TYPE_SHA1) {
453 return check_host_key_hash(s, hkc->u.hash.hash,
454 LIBSSH2_HOSTKEY_HASH_SHA1, 20, errp);
456 g_assert_not_reached();
457 break;
458 case SSH_HOST_KEY_CHECK_MODE_KNOWN_HOSTS:
459 return check_host_key_knownhosts(s, host, port, errp);
460 default:
461 g_assert_not_reached();
464 return -EINVAL;
467 static int authenticate(BDRVSSHState *s, const char *user, Error **errp)
469 int r, ret;
470 const char *userauthlist;
471 LIBSSH2_AGENT *agent = NULL;
472 struct libssh2_agent_publickey *identity;
473 struct libssh2_agent_publickey *prev_identity = NULL;
475 userauthlist = libssh2_userauth_list(s->session, user, strlen(user));
476 if (strstr(userauthlist, "publickey") == NULL) {
477 ret = -EPERM;
478 error_setg(errp,
479 "remote server does not support \"publickey\" authentication");
480 goto out;
483 /* Connect to ssh-agent and try each identity in turn. */
484 agent = libssh2_agent_init(s->session);
485 if (!agent) {
486 ret = -EINVAL;
487 session_error_setg(errp, s, "failed to initialize ssh-agent support");
488 goto out;
490 if (libssh2_agent_connect(agent)) {
491 ret = -ECONNREFUSED;
492 session_error_setg(errp, s, "failed to connect to ssh-agent");
493 goto out;
495 if (libssh2_agent_list_identities(agent)) {
496 ret = -EINVAL;
497 session_error_setg(errp, s,
498 "failed requesting identities from ssh-agent");
499 goto out;
502 for(;;) {
503 r = libssh2_agent_get_identity(agent, &identity, prev_identity);
504 if (r == 1) { /* end of list */
505 break;
507 if (r < 0) {
508 ret = -EINVAL;
509 session_error_setg(errp, s,
510 "failed to obtain identity from ssh-agent");
511 goto out;
513 r = libssh2_agent_userauth(agent, user, identity);
514 if (r == 0) {
515 /* Authenticated! */
516 ret = 0;
517 goto out;
519 /* Failed to authenticate with this identity, try the next one. */
520 prev_identity = identity;
523 ret = -EPERM;
524 error_setg(errp, "failed to authenticate using publickey authentication "
525 "and the identities held by your ssh-agent");
527 out:
528 if (agent != NULL) {
529 /* Note: libssh2 implementation implicitly calls
530 * libssh2_agent_disconnect if necessary.
532 libssh2_agent_free(agent);
535 return ret;
538 static QemuOptsList ssh_runtime_opts = {
539 .name = "ssh",
540 .head = QTAILQ_HEAD_INITIALIZER(ssh_runtime_opts.head),
541 .desc = {
543 .name = "host",
544 .type = QEMU_OPT_STRING,
545 .help = "Host to connect to",
548 .name = "port",
549 .type = QEMU_OPT_NUMBER,
550 .help = "Port to connect to",
553 .name = "host_key_check",
554 .type = QEMU_OPT_STRING,
555 .help = "Defines how and what to check the host key against",
557 { /* end of list */ }
561 static bool ssh_process_legacy_options(QDict *output_opts,
562 QemuOpts *legacy_opts,
563 Error **errp)
565 const char *host = qemu_opt_get(legacy_opts, "host");
566 const char *port = qemu_opt_get(legacy_opts, "port");
567 const char *host_key_check = qemu_opt_get(legacy_opts, "host_key_check");
569 if (!host && port) {
570 error_setg(errp, "port may not be used without host");
571 return false;
574 if (host) {
575 qdict_put_str(output_opts, "server.host", host);
576 qdict_put_str(output_opts, "server.port", port ?: stringify(22));
579 if (host_key_check) {
580 if (strcmp(host_key_check, "no") == 0) {
581 qdict_put_str(output_opts, "host-key-check.mode", "none");
582 } else if (strncmp(host_key_check, "md5:", 4) == 0) {
583 qdict_put_str(output_opts, "host-key-check.mode", "hash");
584 qdict_put_str(output_opts, "host-key-check.type", "md5");
585 qdict_put_str(output_opts, "host-key-check.hash",
586 &host_key_check[4]);
587 } else if (strncmp(host_key_check, "sha1:", 5) == 0) {
588 qdict_put_str(output_opts, "host-key-check.mode", "hash");
589 qdict_put_str(output_opts, "host-key-check.type", "sha1");
590 qdict_put_str(output_opts, "host-key-check.hash",
591 &host_key_check[5]);
592 } else if (strcmp(host_key_check, "yes") == 0) {
593 qdict_put_str(output_opts, "host-key-check.mode", "known_hosts");
594 } else {
595 error_setg(errp, "unknown host_key_check setting (%s)",
596 host_key_check);
597 return false;
601 return true;
604 static BlockdevOptionsSsh *ssh_parse_options(QDict *options, Error **errp)
606 BlockdevOptionsSsh *result = NULL;
607 QemuOpts *opts = NULL;
608 Error *local_err = NULL;
609 const QDictEntry *e;
610 Visitor *v;
612 /* Translate legacy options */
613 opts = qemu_opts_create(&ssh_runtime_opts, NULL, 0, &error_abort);
614 qemu_opts_absorb_qdict(opts, options, &local_err);
615 if (local_err) {
616 error_propagate(errp, local_err);
617 goto fail;
620 if (!ssh_process_legacy_options(options, opts, errp)) {
621 goto fail;
624 /* Create the QAPI object */
625 v = qobject_input_visitor_new_flat_confused(options, errp);
626 if (!v) {
627 goto fail;
630 visit_type_BlockdevOptionsSsh(v, NULL, &result, &local_err);
631 visit_free(v);
633 if (local_err) {
634 error_propagate(errp, local_err);
635 goto fail;
638 /* Remove the processed options from the QDict (the visitor processes
639 * _all_ options in the QDict) */
640 while ((e = qdict_first(options))) {
641 qdict_del(options, e->key);
644 fail:
645 qemu_opts_del(opts);
646 return result;
649 static int connect_to_ssh(BDRVSSHState *s, BlockdevOptionsSsh *opts,
650 int ssh_flags, int creat_mode, Error **errp)
652 int r, ret;
653 const char *user;
654 long port = 0;
656 if (opts->has_user) {
657 user = opts->user;
658 } else {
659 user = g_get_user_name();
660 if (!user) {
661 error_setg_errno(errp, errno, "Can't get user name");
662 ret = -errno;
663 goto err;
667 /* Pop the config into our state object, Exit if invalid */
668 s->inet = opts->server;
669 opts->server = NULL;
671 if (qemu_strtol(s->inet->port, NULL, 10, &port) < 0) {
672 error_setg(errp, "Use only numeric port value");
673 ret = -EINVAL;
674 goto err;
677 /* Open the socket and connect. */
678 s->sock = inet_connect_saddr(s->inet, errp);
679 if (s->sock < 0) {
680 ret = -EIO;
681 goto err;
684 /* Create SSH session. */
685 s->session = libssh2_session_init();
686 if (!s->session) {
687 ret = -EINVAL;
688 session_error_setg(errp, s, "failed to initialize libssh2 session");
689 goto err;
692 #if TRACE_LIBSSH2 != 0
693 libssh2_trace(s->session, TRACE_LIBSSH2);
694 #endif
696 r = libssh2_session_handshake(s->session, s->sock);
697 if (r != 0) {
698 ret = -EINVAL;
699 session_error_setg(errp, s, "failed to establish SSH session");
700 goto err;
703 /* Check the remote host's key against known_hosts. */
704 ret = check_host_key(s, s->inet->host, port, opts->host_key_check, errp);
705 if (ret < 0) {
706 goto err;
709 /* Authenticate. */
710 ret = authenticate(s, user, errp);
711 if (ret < 0) {
712 goto err;
715 /* Start SFTP. */
716 s->sftp = libssh2_sftp_init(s->session);
717 if (!s->sftp) {
718 session_error_setg(errp, s, "failed to initialize sftp handle");
719 ret = -EINVAL;
720 goto err;
723 /* Open the remote file. */
724 DPRINTF("opening file %s flags=0x%x creat_mode=0%o",
725 opts->path, ssh_flags, creat_mode);
726 s->sftp_handle = libssh2_sftp_open(s->sftp, opts->path, ssh_flags,
727 creat_mode);
728 if (!s->sftp_handle) {
729 session_error_setg(errp, s, "failed to open remote file '%s'",
730 opts->path);
731 ret = -EINVAL;
732 goto err;
735 r = libssh2_sftp_fstat(s->sftp_handle, &s->attrs);
736 if (r < 0) {
737 sftp_error_setg(errp, s, "failed to read file attributes");
738 return -EINVAL;
741 return 0;
743 err:
744 if (s->sftp_handle) {
745 libssh2_sftp_close(s->sftp_handle);
747 s->sftp_handle = NULL;
748 if (s->sftp) {
749 libssh2_sftp_shutdown(s->sftp);
751 s->sftp = NULL;
752 if (s->session) {
753 libssh2_session_disconnect(s->session,
754 "from qemu ssh client: "
755 "error opening connection");
756 libssh2_session_free(s->session);
758 s->session = NULL;
760 return ret;
763 static int ssh_file_open(BlockDriverState *bs, QDict *options, int bdrv_flags,
764 Error **errp)
766 BDRVSSHState *s = bs->opaque;
767 BlockdevOptionsSsh *opts;
768 int ret;
769 int ssh_flags;
771 ssh_state_init(s);
773 ssh_flags = LIBSSH2_FXF_READ;
774 if (bdrv_flags & BDRV_O_RDWR) {
775 ssh_flags |= LIBSSH2_FXF_WRITE;
778 opts = ssh_parse_options(options, errp);
779 if (opts == NULL) {
780 return -EINVAL;
783 /* Start up SSH. */
784 ret = connect_to_ssh(s, opts, ssh_flags, 0, errp);
785 if (ret < 0) {
786 goto err;
789 /* Go non-blocking. */
790 libssh2_session_set_blocking(s->session, 0);
792 qapi_free_BlockdevOptionsSsh(opts);
794 return 0;
796 err:
797 if (s->sock >= 0) {
798 close(s->sock);
800 s->sock = -1;
802 qapi_free_BlockdevOptionsSsh(opts);
804 return ret;
807 /* Note: This is a blocking operation */
808 static int ssh_grow_file(BDRVSSHState *s, int64_t offset, Error **errp)
810 ssize_t ret;
811 char c[1] = { '\0' };
812 int was_blocking = libssh2_session_get_blocking(s->session);
814 /* offset must be strictly greater than the current size so we do
815 * not overwrite anything */
816 assert(offset > 0 && offset > s->attrs.filesize);
818 libssh2_session_set_blocking(s->session, 1);
820 libssh2_sftp_seek64(s->sftp_handle, offset - 1);
821 ret = libssh2_sftp_write(s->sftp_handle, c, 1);
823 libssh2_session_set_blocking(s->session, was_blocking);
825 if (ret < 0) {
826 sftp_error_setg(errp, s, "Failed to grow file");
827 return -EIO;
830 s->attrs.filesize = offset;
831 return 0;
834 static QemuOptsList ssh_create_opts = {
835 .name = "ssh-create-opts",
836 .head = QTAILQ_HEAD_INITIALIZER(ssh_create_opts.head),
837 .desc = {
839 .name = BLOCK_OPT_SIZE,
840 .type = QEMU_OPT_SIZE,
841 .help = "Virtual disk size"
843 { /* end of list */ }
847 static int ssh_co_create(BlockdevCreateOptions *options, Error **errp)
849 BlockdevCreateOptionsSsh *opts = &options->u.ssh;
850 BDRVSSHState s;
851 int ret;
853 assert(options->driver == BLOCKDEV_DRIVER_SSH);
855 ssh_state_init(&s);
857 ret = connect_to_ssh(&s, opts->location,
858 LIBSSH2_FXF_READ|LIBSSH2_FXF_WRITE|
859 LIBSSH2_FXF_CREAT|LIBSSH2_FXF_TRUNC,
860 0644, errp);
861 if (ret < 0) {
862 goto fail;
865 if (opts->size > 0) {
866 ret = ssh_grow_file(&s, opts->size, errp);
867 if (ret < 0) {
868 goto fail;
872 ret = 0;
873 fail:
874 ssh_state_free(&s);
875 return ret;
878 static int coroutine_fn ssh_co_create_opts(const char *filename, QemuOpts *opts,
879 Error **errp)
881 BlockdevCreateOptions *create_options;
882 BlockdevCreateOptionsSsh *ssh_opts;
883 int ret;
884 QDict *uri_options = NULL;
886 create_options = g_new0(BlockdevCreateOptions, 1);
887 create_options->driver = BLOCKDEV_DRIVER_SSH;
888 ssh_opts = &create_options->u.ssh;
890 /* Get desired file size. */
891 ssh_opts->size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
892 BDRV_SECTOR_SIZE);
893 DPRINTF("total_size=%" PRIi64, ssh_opts->size);
895 uri_options = qdict_new();
896 ret = parse_uri(filename, uri_options, errp);
897 if (ret < 0) {
898 goto out;
901 ssh_opts->location = ssh_parse_options(uri_options, errp);
902 if (ssh_opts->location == NULL) {
903 ret = -EINVAL;
904 goto out;
907 ret = ssh_co_create(create_options, errp);
909 out:
910 qobject_unref(uri_options);
911 qapi_free_BlockdevCreateOptions(create_options);
912 return ret;
915 static void ssh_close(BlockDriverState *bs)
917 BDRVSSHState *s = bs->opaque;
919 ssh_state_free(s);
922 static int ssh_has_zero_init(BlockDriverState *bs)
924 BDRVSSHState *s = bs->opaque;
925 /* Assume false, unless we can positively prove it's true. */
926 int has_zero_init = 0;
928 if (s->attrs.flags & LIBSSH2_SFTP_ATTR_PERMISSIONS) {
929 if (s->attrs.permissions & LIBSSH2_SFTP_S_IFREG) {
930 has_zero_init = 1;
934 return has_zero_init;
937 typedef struct BDRVSSHRestart {
938 BlockDriverState *bs;
939 Coroutine *co;
940 } BDRVSSHRestart;
942 static void restart_coroutine(void *opaque)
944 BDRVSSHRestart *restart = opaque;
945 BlockDriverState *bs = restart->bs;
946 BDRVSSHState *s = bs->opaque;
947 AioContext *ctx = bdrv_get_aio_context(bs);
949 DPRINTF("co=%p", restart->co);
950 aio_set_fd_handler(ctx, s->sock, false, NULL, NULL, NULL, NULL);
952 aio_co_wake(restart->co);
955 /* A non-blocking call returned EAGAIN, so yield, ensuring the
956 * handlers are set up so that we'll be rescheduled when there is an
957 * interesting event on the socket.
959 static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
961 int r;
962 IOHandler *rd_handler = NULL, *wr_handler = NULL;
963 BDRVSSHRestart restart = {
964 .bs = bs,
965 .co = qemu_coroutine_self()
968 r = libssh2_session_block_directions(s->session);
970 if (r & LIBSSH2_SESSION_BLOCK_INBOUND) {
971 rd_handler = restart_coroutine;
973 if (r & LIBSSH2_SESSION_BLOCK_OUTBOUND) {
974 wr_handler = restart_coroutine;
977 DPRINTF("s->sock=%d rd_handler=%p wr_handler=%p", s->sock,
978 rd_handler, wr_handler);
980 aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
981 false, rd_handler, wr_handler, NULL, &restart);
982 qemu_coroutine_yield();
983 DPRINTF("s->sock=%d - back", s->sock);
986 /* SFTP has a function `libssh2_sftp_seek64' which seeks to a position
987 * in the remote file. Notice that it just updates a field in the
988 * sftp_handle structure, so there is no network traffic and it cannot
989 * fail.
991 * However, `libssh2_sftp_seek64' does have a catastrophic effect on
992 * performance since it causes the handle to throw away all in-flight
993 * reads and buffered readahead data. Therefore this function tries
994 * to be intelligent about when to call the underlying libssh2 function.
996 #define SSH_SEEK_WRITE 0
997 #define SSH_SEEK_READ 1
998 #define SSH_SEEK_FORCE 2
1000 static void ssh_seek(BDRVSSHState *s, int64_t offset, int flags)
1002 bool op_read = (flags & SSH_SEEK_READ) != 0;
1003 bool force = (flags & SSH_SEEK_FORCE) != 0;
1005 if (force || op_read != s->offset_op_read || offset != s->offset) {
1006 DPRINTF("seeking to offset=%" PRIi64, offset);
1007 libssh2_sftp_seek64(s->sftp_handle, offset);
1008 s->offset = offset;
1009 s->offset_op_read = op_read;
1013 static coroutine_fn int ssh_read(BDRVSSHState *s, BlockDriverState *bs,
1014 int64_t offset, size_t size,
1015 QEMUIOVector *qiov)
1017 ssize_t r;
1018 size_t got;
1019 char *buf, *end_of_vec;
1020 struct iovec *i;
1022 DPRINTF("offset=%" PRIi64 " size=%zu", offset, size);
1024 ssh_seek(s, offset, SSH_SEEK_READ);
1026 /* This keeps track of the current iovec element ('i'), where we
1027 * will write to next ('buf'), and the end of the current iovec
1028 * ('end_of_vec').
1030 i = &qiov->iov[0];
1031 buf = i->iov_base;
1032 end_of_vec = i->iov_base + i->iov_len;
1034 /* libssh2 has a hard-coded limit of 2000 bytes per request,
1035 * although it will also do readahead behind our backs. Therefore
1036 * we may have to do repeated reads here until we have read 'size'
1037 * bytes.
1039 for (got = 0; got < size; ) {
1040 again:
1041 DPRINTF("sftp_read buf=%p size=%zu", buf, end_of_vec - buf);
1042 r = libssh2_sftp_read(s->sftp_handle, buf, end_of_vec - buf);
1043 DPRINTF("sftp_read returned %zd", r);
1045 if (r == LIBSSH2_ERROR_EAGAIN || r == LIBSSH2_ERROR_TIMEOUT) {
1046 co_yield(s, bs);
1047 goto again;
1049 if (r < 0) {
1050 sftp_error_report(s, "read failed");
1051 s->offset = -1;
1052 return -EIO;
1054 if (r == 0) {
1055 /* EOF: Short read so pad the buffer with zeroes and return it. */
1056 qemu_iovec_memset(qiov, got, 0, size - got);
1057 return 0;
1060 got += r;
1061 buf += r;
1062 s->offset += r;
1063 if (buf >= end_of_vec && got < size) {
1064 i++;
1065 buf = i->iov_base;
1066 end_of_vec = i->iov_base + i->iov_len;
1070 return 0;
1073 static coroutine_fn int ssh_co_readv(BlockDriverState *bs,
1074 int64_t sector_num,
1075 int nb_sectors, QEMUIOVector *qiov)
1077 BDRVSSHState *s = bs->opaque;
1078 int ret;
1080 qemu_co_mutex_lock(&s->lock);
1081 ret = ssh_read(s, bs, sector_num * BDRV_SECTOR_SIZE,
1082 nb_sectors * BDRV_SECTOR_SIZE, qiov);
1083 qemu_co_mutex_unlock(&s->lock);
1085 return ret;
1088 static int ssh_write(BDRVSSHState *s, BlockDriverState *bs,
1089 int64_t offset, size_t size,
1090 QEMUIOVector *qiov)
1092 ssize_t r;
1093 size_t written;
1094 char *buf, *end_of_vec;
1095 struct iovec *i;
1097 DPRINTF("offset=%" PRIi64 " size=%zu", offset, size);
1099 ssh_seek(s, offset, SSH_SEEK_WRITE);
1101 /* This keeps track of the current iovec element ('i'), where we
1102 * will read from next ('buf'), and the end of the current iovec
1103 * ('end_of_vec').
1105 i = &qiov->iov[0];
1106 buf = i->iov_base;
1107 end_of_vec = i->iov_base + i->iov_len;
1109 for (written = 0; written < size; ) {
1110 again:
1111 DPRINTF("sftp_write buf=%p size=%zu", buf, end_of_vec - buf);
1112 r = libssh2_sftp_write(s->sftp_handle, buf, end_of_vec - buf);
1113 DPRINTF("sftp_write returned %zd", r);
1115 if (r == LIBSSH2_ERROR_EAGAIN || r == LIBSSH2_ERROR_TIMEOUT) {
1116 co_yield(s, bs);
1117 goto again;
1119 if (r < 0) {
1120 sftp_error_report(s, "write failed");
1121 s->offset = -1;
1122 return -EIO;
1124 /* The libssh2 API is very unclear about this. A comment in
1125 * the code says "nothing was acked, and no EAGAIN was
1126 * received!" which apparently means that no data got sent
1127 * out, and the underlying channel didn't return any EAGAIN
1128 * indication. I think this is a bug in either libssh2 or
1129 * OpenSSH (server-side). In any case, forcing a seek (to
1130 * discard libssh2 internal buffers), and then trying again
1131 * works for me.
1133 if (r == 0) {
1134 ssh_seek(s, offset + written, SSH_SEEK_WRITE|SSH_SEEK_FORCE);
1135 co_yield(s, bs);
1136 goto again;
1139 written += r;
1140 buf += r;
1141 s->offset += r;
1142 if (buf >= end_of_vec && written < size) {
1143 i++;
1144 buf = i->iov_base;
1145 end_of_vec = i->iov_base + i->iov_len;
1148 if (offset + written > s->attrs.filesize)
1149 s->attrs.filesize = offset + written;
1152 return 0;
1155 static coroutine_fn int ssh_co_writev(BlockDriverState *bs,
1156 int64_t sector_num,
1157 int nb_sectors, QEMUIOVector *qiov,
1158 int flags)
1160 BDRVSSHState *s = bs->opaque;
1161 int ret;
1163 assert(!flags);
1164 qemu_co_mutex_lock(&s->lock);
1165 ret = ssh_write(s, bs, sector_num * BDRV_SECTOR_SIZE,
1166 nb_sectors * BDRV_SECTOR_SIZE, qiov);
1167 qemu_co_mutex_unlock(&s->lock);
1169 return ret;
1172 static void unsafe_flush_warning(BDRVSSHState *s, const char *what)
1174 if (!s->unsafe_flush_warning) {
1175 warn_report("ssh server %s does not support fsync",
1176 s->inet->host);
1177 if (what) {
1178 error_report("to support fsync, you need %s", what);
1180 s->unsafe_flush_warning = true;
1184 #ifdef HAS_LIBSSH2_SFTP_FSYNC
1186 static coroutine_fn int ssh_flush(BDRVSSHState *s, BlockDriverState *bs)
1188 int r;
1190 DPRINTF("fsync");
1191 again:
1192 r = libssh2_sftp_fsync(s->sftp_handle);
1193 if (r == LIBSSH2_ERROR_EAGAIN || r == LIBSSH2_ERROR_TIMEOUT) {
1194 co_yield(s, bs);
1195 goto again;
1197 if (r == LIBSSH2_ERROR_SFTP_PROTOCOL &&
1198 libssh2_sftp_last_error(s->sftp) == LIBSSH2_FX_OP_UNSUPPORTED) {
1199 unsafe_flush_warning(s, "OpenSSH >= 6.3");
1200 return 0;
1202 if (r < 0) {
1203 sftp_error_report(s, "fsync failed");
1204 return -EIO;
1207 return 0;
1210 static coroutine_fn int ssh_co_flush(BlockDriverState *bs)
1212 BDRVSSHState *s = bs->opaque;
1213 int ret;
1215 qemu_co_mutex_lock(&s->lock);
1216 ret = ssh_flush(s, bs);
1217 qemu_co_mutex_unlock(&s->lock);
1219 return ret;
1222 #else /* !HAS_LIBSSH2_SFTP_FSYNC */
1224 static coroutine_fn int ssh_co_flush(BlockDriverState *bs)
1226 BDRVSSHState *s = bs->opaque;
1228 unsafe_flush_warning(s, "libssh2 >= 1.4.4");
1229 return 0;
1232 #endif /* !HAS_LIBSSH2_SFTP_FSYNC */
1234 static int64_t ssh_getlength(BlockDriverState *bs)
1236 BDRVSSHState *s = bs->opaque;
1237 int64_t length;
1239 /* Note we cannot make a libssh2 call here. */
1240 length = (int64_t) s->attrs.filesize;
1241 DPRINTF("length=%" PRIi64, length);
1243 return length;
1246 static int coroutine_fn ssh_co_truncate(BlockDriverState *bs, int64_t offset,
1247 PreallocMode prealloc, Error **errp)
1249 BDRVSSHState *s = bs->opaque;
1251 if (prealloc != PREALLOC_MODE_OFF) {
1252 error_setg(errp, "Unsupported preallocation mode '%s'",
1253 PreallocMode_str(prealloc));
1254 return -ENOTSUP;
1257 if (offset < s->attrs.filesize) {
1258 error_setg(errp, "ssh driver does not support shrinking files");
1259 return -ENOTSUP;
1262 if (offset == s->attrs.filesize) {
1263 return 0;
1266 return ssh_grow_file(s, offset, errp);
1269 static BlockDriver bdrv_ssh = {
1270 .format_name = "ssh",
1271 .protocol_name = "ssh",
1272 .instance_size = sizeof(BDRVSSHState),
1273 .bdrv_parse_filename = ssh_parse_filename,
1274 .bdrv_file_open = ssh_file_open,
1275 .bdrv_co_create = ssh_co_create,
1276 .bdrv_co_create_opts = ssh_co_create_opts,
1277 .bdrv_close = ssh_close,
1278 .bdrv_has_zero_init = ssh_has_zero_init,
1279 .bdrv_co_readv = ssh_co_readv,
1280 .bdrv_co_writev = ssh_co_writev,
1281 .bdrv_getlength = ssh_getlength,
1282 .bdrv_co_truncate = ssh_co_truncate,
1283 .bdrv_co_flush_to_disk = ssh_co_flush,
1284 .create_opts = &ssh_create_opts,
1287 static void bdrv_ssh_init(void)
1289 int r;
1291 r = libssh2_init(0);
1292 if (r != 0) {
1293 fprintf(stderr, "libssh2 initialization failed, %d\n", r);
1294 exit(EXIT_FAILURE);
1297 bdrv_register(&bdrv_ssh);
1300 block_init(bdrv_ssh_init);