1143 lines
31 KiB
C
1143 lines
31 KiB
C
/*
|
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* Secure Shell (ssh) backend for QEMU.
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*
|
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* Copyright (C) 2013 Red Hat Inc., Richard W.M. Jones <rjones@redhat.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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|
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#include <libssh2.h>
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#include <libssh2_sftp.h>
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#include "block/block_int.h"
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#include "qapi/error.h"
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#include "qemu/error-report.h"
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#include "qemu/sockets.h"
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#include "qemu/uri.h"
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#include "qapi/qmp/qint.h"
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#include "qapi/qmp/qstring.h"
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/* DEBUG_SSH=1 enables the DPRINTF (debugging printf) statements in
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* this block driver code.
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*
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* TRACE_LIBSSH2=<bitmask> enables tracing in libssh2 itself. Note
|
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* that this requires that libssh2 was specially compiled with the
|
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* `./configure --enable-debug' option, so most likely you will have
|
|
* to compile it yourself. The meaning of <bitmask> is described
|
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* here: http://www.libssh2.org/libssh2_trace.html
|
|
*/
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#define DEBUG_SSH 0
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#define TRACE_LIBSSH2 0 /* or try: LIBSSH2_TRACE_SFTP */
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|
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#define DPRINTF(fmt, ...) \
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do { \
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if (DEBUG_SSH) { \
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fprintf(stderr, "ssh: %-15s " fmt "\n", \
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__func__, ##__VA_ARGS__); \
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|
} \
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} while (0)
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typedef struct BDRVSSHState {
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/* Coroutine. */
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CoMutex lock;
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/* SSH connection. */
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int sock; /* socket */
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LIBSSH2_SESSION *session; /* ssh session */
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LIBSSH2_SFTP *sftp; /* sftp session */
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LIBSSH2_SFTP_HANDLE *sftp_handle; /* sftp remote file handle */
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/* See ssh_seek() function below. */
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int64_t offset;
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bool offset_op_read;
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|
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/* File attributes at open. We try to keep the .filesize field
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* updated if it changes (eg by writing at the end of the file).
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*/
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LIBSSH2_SFTP_ATTRIBUTES attrs;
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/* Used to warn if 'flush' is not supported. */
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char *hostport;
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bool unsafe_flush_warning;
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} BDRVSSHState;
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static void ssh_state_init(BDRVSSHState *s)
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{
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memset(s, 0, sizeof *s);
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s->sock = -1;
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s->offset = -1;
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qemu_co_mutex_init(&s->lock);
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}
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static void ssh_state_free(BDRVSSHState *s)
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{
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g_free(s->hostport);
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if (s->sftp_handle) {
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libssh2_sftp_close(s->sftp_handle);
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}
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if (s->sftp) {
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libssh2_sftp_shutdown(s->sftp);
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}
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if (s->session) {
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libssh2_session_disconnect(s->session,
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"from qemu ssh client: "
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"user closed the connection");
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libssh2_session_free(s->session);
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}
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if (s->sock >= 0) {
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close(s->sock);
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}
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}
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static void GCC_FMT_ATTR(3, 4)
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session_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
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{
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va_list args;
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char *msg;
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va_start(args, fs);
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msg = g_strdup_vprintf(fs, args);
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va_end(args);
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if (s->session) {
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char *ssh_err;
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int ssh_err_code;
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/* This is not an errno. See <libssh2.h>. */
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ssh_err_code = libssh2_session_last_error(s->session,
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&ssh_err, NULL, 0);
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error_setg(errp, "%s: %s (libssh2 error code: %d)",
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msg, ssh_err, ssh_err_code);
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} else {
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error_setg(errp, "%s", msg);
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}
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g_free(msg);
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}
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static void GCC_FMT_ATTR(3, 4)
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sftp_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
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{
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va_list args;
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char *msg;
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va_start(args, fs);
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msg = g_strdup_vprintf(fs, args);
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va_end(args);
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if (s->sftp) {
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char *ssh_err;
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int ssh_err_code;
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unsigned long sftp_err_code;
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/* This is not an errno. See <libssh2.h>. */
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ssh_err_code = libssh2_session_last_error(s->session,
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&ssh_err, NULL, 0);
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/* See <libssh2_sftp.h>. */
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sftp_err_code = libssh2_sftp_last_error((s)->sftp);
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error_setg(errp,
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"%s: %s (libssh2 error code: %d, sftp error code: %lu)",
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msg, ssh_err, ssh_err_code, sftp_err_code);
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} else {
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error_setg(errp, "%s", msg);
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}
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g_free(msg);
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}
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static void GCC_FMT_ATTR(2, 3)
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sftp_error_report(BDRVSSHState *s, const char *fs, ...)
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{
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va_list args;
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va_start(args, fs);
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error_vprintf(fs, args);
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if ((s)->sftp) {
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char *ssh_err;
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int ssh_err_code;
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unsigned long sftp_err_code;
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/* This is not an errno. See <libssh2.h>. */
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ssh_err_code = libssh2_session_last_error(s->session,
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&ssh_err, NULL, 0);
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/* See <libssh2_sftp.h>. */
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sftp_err_code = libssh2_sftp_last_error((s)->sftp);
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error_printf(": %s (libssh2 error code: %d, sftp error code: %lu)",
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ssh_err, ssh_err_code, sftp_err_code);
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}
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va_end(args);
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error_printf("\n");
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}
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static int parse_uri(const char *filename, QDict *options, Error **errp)
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{
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URI *uri = NULL;
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QueryParams *qp;
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int i;
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uri = uri_parse(filename);
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if (!uri) {
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return -EINVAL;
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}
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if (strcmp(uri->scheme, "ssh") != 0) {
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error_setg(errp, "URI scheme must be 'ssh'");
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goto err;
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}
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if (!uri->server || strcmp(uri->server, "") == 0) {
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error_setg(errp, "missing hostname in URI");
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goto err;
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}
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if (!uri->path || strcmp(uri->path, "") == 0) {
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error_setg(errp, "missing remote path in URI");
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goto err;
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}
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qp = query_params_parse(uri->query);
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if (!qp) {
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error_setg(errp, "could not parse query parameters");
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goto err;
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}
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if(uri->user && strcmp(uri->user, "") != 0) {
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qdict_put(options, "user", qstring_from_str(uri->user));
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}
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qdict_put(options, "host", qstring_from_str(uri->server));
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if (uri->port) {
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qdict_put(options, "port", qint_from_int(uri->port));
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}
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qdict_put(options, "path", qstring_from_str(uri->path));
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/* Pick out any query parameters that we understand, and ignore
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* the rest.
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*/
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for (i = 0; i < qp->n; ++i) {
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if (strcmp(qp->p[i].name, "host_key_check") == 0) {
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qdict_put(options, "host_key_check",
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qstring_from_str(qp->p[i].value));
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}
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}
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query_params_free(qp);
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uri_free(uri);
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return 0;
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err:
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if (uri) {
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uri_free(uri);
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}
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return -EINVAL;
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}
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static void ssh_parse_filename(const char *filename, QDict *options,
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Error **errp)
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{
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if (qdict_haskey(options, "user") ||
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qdict_haskey(options, "host") ||
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qdict_haskey(options, "port") ||
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qdict_haskey(options, "path") ||
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qdict_haskey(options, "host_key_check")) {
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error_setg(errp, "user, host, port, path, host_key_check cannot be used at the same time as a file option");
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return;
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}
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parse_uri(filename, options, errp);
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}
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static int check_host_key_knownhosts(BDRVSSHState *s,
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const char *host, int port, Error **errp)
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{
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const char *home;
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char *knh_file = NULL;
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LIBSSH2_KNOWNHOSTS *knh = NULL;
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struct libssh2_knownhost *found;
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int ret, r;
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const char *hostkey;
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size_t len;
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int type;
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hostkey = libssh2_session_hostkey(s->session, &len, &type);
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if (!hostkey) {
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ret = -EINVAL;
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session_error_setg(errp, s, "failed to read remote host key");
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goto out;
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}
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knh = libssh2_knownhost_init(s->session);
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if (!knh) {
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ret = -EINVAL;
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session_error_setg(errp, s,
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"failed to initialize known hosts support");
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goto out;
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}
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home = getenv("HOME");
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if (home) {
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knh_file = g_strdup_printf("%s/.ssh/known_hosts", home);
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} else {
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knh_file = g_strdup_printf("/root/.ssh/known_hosts");
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}
|
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|
|
/* Read all known hosts from OpenSSH-style known_hosts file. */
|
|
libssh2_knownhost_readfile(knh, knh_file, LIBSSH2_KNOWNHOST_FILE_OPENSSH);
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|
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r = libssh2_knownhost_checkp(knh, host, port, hostkey, len,
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LIBSSH2_KNOWNHOST_TYPE_PLAIN|
|
|
LIBSSH2_KNOWNHOST_KEYENC_RAW,
|
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&found);
|
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switch (r) {
|
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case LIBSSH2_KNOWNHOST_CHECK_MATCH:
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/* OK */
|
|
DPRINTF("host key OK: %s", found->key);
|
|
break;
|
|
case LIBSSH2_KNOWNHOST_CHECK_MISMATCH:
|
|
ret = -EINVAL;
|
|
session_error_setg(errp, s,
|
|
"host key does not match the one in known_hosts"
|
|
" (found key %s)", found->key);
|
|
goto out;
|
|
case LIBSSH2_KNOWNHOST_CHECK_NOTFOUND:
|
|
ret = -EINVAL;
|
|
session_error_setg(errp, s, "no host key was found in known_hosts");
|
|
goto out;
|
|
case LIBSSH2_KNOWNHOST_CHECK_FAILURE:
|
|
ret = -EINVAL;
|
|
session_error_setg(errp, s,
|
|
"failure matching the host key with known_hosts");
|
|
goto out;
|
|
default:
|
|
ret = -EINVAL;
|
|
session_error_setg(errp, s, "unknown error matching the host key"
|
|
" with known_hosts (%d)", r);
|
|
goto out;
|
|
}
|
|
|
|
/* known_hosts checking successful. */
|
|
ret = 0;
|
|
|
|
out:
|
|
if (knh != NULL) {
|
|
libssh2_knownhost_free(knh);
|
|
}
|
|
g_free(knh_file);
|
|
return ret;
|
|
}
|
|
|
|
static unsigned hex2decimal(char ch)
|
|
{
|
|
if (ch >= '0' && ch <= '9') {
|
|
return (ch - '0');
|
|
} else if (ch >= 'a' && ch <= 'f') {
|
|
return 10 + (ch - 'a');
|
|
} else if (ch >= 'A' && ch <= 'F') {
|
|
return 10 + (ch - 'A');
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|
|
/* Compare the binary fingerprint (hash of host key) with the
|
|
* host_key_check parameter.
|
|
*/
|
|
static int compare_fingerprint(const unsigned char *fingerprint, size_t len,
|
|
const char *host_key_check)
|
|
{
|
|
unsigned c;
|
|
|
|
while (len > 0) {
|
|
while (*host_key_check == ':')
|
|
host_key_check++;
|
|
if (!qemu_isxdigit(host_key_check[0]) ||
|
|
!qemu_isxdigit(host_key_check[1]))
|
|
return 1;
|
|
c = hex2decimal(host_key_check[0]) * 16 +
|
|
hex2decimal(host_key_check[1]);
|
|
if (c - *fingerprint != 0)
|
|
return c - *fingerprint;
|
|
fingerprint++;
|
|
len--;
|
|
host_key_check += 2;
|
|
}
|
|
return *host_key_check - '\0';
|
|
}
|
|
|
|
static int
|
|
check_host_key_hash(BDRVSSHState *s, const char *hash,
|
|
int hash_type, size_t fingerprint_len, Error **errp)
|
|
{
|
|
const char *fingerprint;
|
|
|
|
fingerprint = libssh2_hostkey_hash(s->session, hash_type);
|
|
if (!fingerprint) {
|
|
session_error_setg(errp, s, "failed to read remote host key");
|
|
return -EINVAL;
|
|
}
|
|
|
|
if(compare_fingerprint((unsigned char *) fingerprint, fingerprint_len,
|
|
hash) != 0) {
|
|
error_setg(errp, "remote host key does not match host_key_check '%s'",
|
|
hash);
|
|
return -EPERM;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int check_host_key(BDRVSSHState *s, const char *host, int port,
|
|
const char *host_key_check, Error **errp)
|
|
{
|
|
/* host_key_check=no */
|
|
if (strcmp(host_key_check, "no") == 0) {
|
|
return 0;
|
|
}
|
|
|
|
/* host_key_check=md5:xx:yy:zz:... */
|
|
if (strncmp(host_key_check, "md5:", 4) == 0) {
|
|
return check_host_key_hash(s, &host_key_check[4],
|
|
LIBSSH2_HOSTKEY_HASH_MD5, 16, errp);
|
|
}
|
|
|
|
/* host_key_check=sha1:xx:yy:zz:... */
|
|
if (strncmp(host_key_check, "sha1:", 5) == 0) {
|
|
return check_host_key_hash(s, &host_key_check[5],
|
|
LIBSSH2_HOSTKEY_HASH_SHA1, 20, errp);
|
|
}
|
|
|
|
/* host_key_check=yes */
|
|
if (strcmp(host_key_check, "yes") == 0) {
|
|
return check_host_key_knownhosts(s, host, port, errp);
|
|
}
|
|
|
|
error_setg(errp, "unknown host_key_check setting (%s)", host_key_check);
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int authenticate(BDRVSSHState *s, const char *user, Error **errp)
|
|
{
|
|
int r, ret;
|
|
const char *userauthlist;
|
|
LIBSSH2_AGENT *agent = NULL;
|
|
struct libssh2_agent_publickey *identity;
|
|
struct libssh2_agent_publickey *prev_identity = NULL;
|
|
|
|
userauthlist = libssh2_userauth_list(s->session, user, strlen(user));
|
|
if (strstr(userauthlist, "publickey") == NULL) {
|
|
ret = -EPERM;
|
|
error_setg(errp,
|
|
"remote server does not support \"publickey\" authentication");
|
|
goto out;
|
|
}
|
|
|
|
/* Connect to ssh-agent and try each identity in turn. */
|
|
agent = libssh2_agent_init(s->session);
|
|
if (!agent) {
|
|
ret = -EINVAL;
|
|
session_error_setg(errp, s, "failed to initialize ssh-agent support");
|
|
goto out;
|
|
}
|
|
if (libssh2_agent_connect(agent)) {
|
|
ret = -ECONNREFUSED;
|
|
session_error_setg(errp, s, "failed to connect to ssh-agent");
|
|
goto out;
|
|
}
|
|
if (libssh2_agent_list_identities(agent)) {
|
|
ret = -EINVAL;
|
|
session_error_setg(errp, s,
|
|
"failed requesting identities from ssh-agent");
|
|
goto out;
|
|
}
|
|
|
|
for(;;) {
|
|
r = libssh2_agent_get_identity(agent, &identity, prev_identity);
|
|
if (r == 1) { /* end of list */
|
|
break;
|
|
}
|
|
if (r < 0) {
|
|
ret = -EINVAL;
|
|
session_error_setg(errp, s,
|
|
"failed to obtain identity from ssh-agent");
|
|
goto out;
|
|
}
|
|
r = libssh2_agent_userauth(agent, user, identity);
|
|
if (r == 0) {
|
|
/* Authenticated! */
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
/* Failed to authenticate with this identity, try the next one. */
|
|
prev_identity = identity;
|
|
}
|
|
|
|
ret = -EPERM;
|
|
error_setg(errp, "failed to authenticate using publickey authentication "
|
|
"and the identities held by your ssh-agent");
|
|
|
|
out:
|
|
if (agent != NULL) {
|
|
/* Note: libssh2 implementation implicitly calls
|
|
* libssh2_agent_disconnect if necessary.
|
|
*/
|
|
libssh2_agent_free(agent);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static QemuOptsList ssh_runtime_opts = {
|
|
.name = "ssh",
|
|
.head = QTAILQ_HEAD_INITIALIZER(ssh_runtime_opts.head),
|
|
.desc = {
|
|
{
|
|
.name = "host",
|
|
.type = QEMU_OPT_STRING,
|
|
.help = "Host to connect to",
|
|
},
|
|
{
|
|
.name = "port",
|
|
.type = QEMU_OPT_NUMBER,
|
|
.help = "Port to connect to",
|
|
},
|
|
{
|
|
.name = "path",
|
|
.type = QEMU_OPT_STRING,
|
|
.help = "Path of the image on the host",
|
|
},
|
|
{
|
|
.name = "user",
|
|
.type = QEMU_OPT_STRING,
|
|
.help = "User as which to connect",
|
|
},
|
|
{
|
|
.name = "host_key_check",
|
|
.type = QEMU_OPT_STRING,
|
|
.help = "Defines how and what to check the host key against",
|
|
},
|
|
},
|
|
};
|
|
|
|
static int connect_to_ssh(BDRVSSHState *s, QDict *options,
|
|
int ssh_flags, int creat_mode, Error **errp)
|
|
{
|
|
int r, ret;
|
|
QemuOpts *opts = NULL;
|
|
Error *local_err = NULL;
|
|
const char *host, *user, *path, *host_key_check;
|
|
int port;
|
|
|
|
opts = qemu_opts_create(&ssh_runtime_opts, NULL, 0, &error_abort);
|
|
qemu_opts_absorb_qdict(opts, options, &local_err);
|
|
if (local_err) {
|
|
ret = -EINVAL;
|
|
error_propagate(errp, local_err);
|
|
goto err;
|
|
}
|
|
|
|
host = qemu_opt_get(opts, "host");
|
|
if (!host) {
|
|
ret = -EINVAL;
|
|
error_setg(errp, "No hostname was specified");
|
|
goto err;
|
|
}
|
|
|
|
port = qemu_opt_get_number(opts, "port", 22);
|
|
|
|
path = qemu_opt_get(opts, "path");
|
|
if (!path) {
|
|
ret = -EINVAL;
|
|
error_setg(errp, "No path was specified");
|
|
goto err;
|
|
}
|
|
|
|
user = qemu_opt_get(opts, "user");
|
|
if (!user) {
|
|
user = g_get_user_name();
|
|
if (!user) {
|
|
error_setg_errno(errp, errno, "Can't get user name");
|
|
ret = -errno;
|
|
goto err;
|
|
}
|
|
}
|
|
|
|
host_key_check = qemu_opt_get(opts, "host_key_check");
|
|
if (!host_key_check) {
|
|
host_key_check = "yes";
|
|
}
|
|
|
|
/* Construct the host:port name for inet_connect. */
|
|
g_free(s->hostport);
|
|
s->hostport = g_strdup_printf("%s:%d", host, port);
|
|
|
|
/* Open the socket and connect. */
|
|
s->sock = inet_connect(s->hostport, errp);
|
|
if (s->sock < 0) {
|
|
ret = -EIO;
|
|
goto err;
|
|
}
|
|
|
|
/* Create SSH session. */
|
|
s->session = libssh2_session_init();
|
|
if (!s->session) {
|
|
ret = -EINVAL;
|
|
session_error_setg(errp, s, "failed to initialize libssh2 session");
|
|
goto err;
|
|
}
|
|
|
|
#if TRACE_LIBSSH2 != 0
|
|
libssh2_trace(s->session, TRACE_LIBSSH2);
|
|
#endif
|
|
|
|
r = libssh2_session_handshake(s->session, s->sock);
|
|
if (r != 0) {
|
|
ret = -EINVAL;
|
|
session_error_setg(errp, s, "failed to establish SSH session");
|
|
goto err;
|
|
}
|
|
|
|
/* Check the remote host's key against known_hosts. */
|
|
ret = check_host_key(s, host, port, host_key_check, errp);
|
|
if (ret < 0) {
|
|
goto err;
|
|
}
|
|
|
|
/* Authenticate. */
|
|
ret = authenticate(s, user, errp);
|
|
if (ret < 0) {
|
|
goto err;
|
|
}
|
|
|
|
/* Start SFTP. */
|
|
s->sftp = libssh2_sftp_init(s->session);
|
|
if (!s->sftp) {
|
|
session_error_setg(errp, s, "failed to initialize sftp handle");
|
|
ret = -EINVAL;
|
|
goto err;
|
|
}
|
|
|
|
/* Open the remote file. */
|
|
DPRINTF("opening file %s flags=0x%x creat_mode=0%o",
|
|
path, ssh_flags, creat_mode);
|
|
s->sftp_handle = libssh2_sftp_open(s->sftp, path, ssh_flags, creat_mode);
|
|
if (!s->sftp_handle) {
|
|
session_error_setg(errp, s, "failed to open remote file '%s'", path);
|
|
ret = -EINVAL;
|
|
goto err;
|
|
}
|
|
|
|
qemu_opts_del(opts);
|
|
|
|
r = libssh2_sftp_fstat(s->sftp_handle, &s->attrs);
|
|
if (r < 0) {
|
|
sftp_error_setg(errp, s, "failed to read file attributes");
|
|
return -EINVAL;
|
|
}
|
|
|
|
return 0;
|
|
|
|
err:
|
|
if (s->sftp_handle) {
|
|
libssh2_sftp_close(s->sftp_handle);
|
|
}
|
|
s->sftp_handle = NULL;
|
|
if (s->sftp) {
|
|
libssh2_sftp_shutdown(s->sftp);
|
|
}
|
|
s->sftp = NULL;
|
|
if (s->session) {
|
|
libssh2_session_disconnect(s->session,
|
|
"from qemu ssh client: "
|
|
"error opening connection");
|
|
libssh2_session_free(s->session);
|
|
}
|
|
s->session = NULL;
|
|
|
|
qemu_opts_del(opts);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int ssh_file_open(BlockDriverState *bs, QDict *options, int bdrv_flags,
|
|
Error **errp)
|
|
{
|
|
BDRVSSHState *s = bs->opaque;
|
|
int ret;
|
|
int ssh_flags;
|
|
|
|
ssh_state_init(s);
|
|
|
|
ssh_flags = LIBSSH2_FXF_READ;
|
|
if (bdrv_flags & BDRV_O_RDWR) {
|
|
ssh_flags |= LIBSSH2_FXF_WRITE;
|
|
}
|
|
|
|
/* Start up SSH. */
|
|
ret = connect_to_ssh(s, options, ssh_flags, 0, errp);
|
|
if (ret < 0) {
|
|
goto err;
|
|
}
|
|
|
|
/* Go non-blocking. */
|
|
libssh2_session_set_blocking(s->session, 0);
|
|
|
|
return 0;
|
|
|
|
err:
|
|
if (s->sock >= 0) {
|
|
close(s->sock);
|
|
}
|
|
s->sock = -1;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static QemuOptsList ssh_create_opts = {
|
|
.name = "ssh-create-opts",
|
|
.head = QTAILQ_HEAD_INITIALIZER(ssh_create_opts.head),
|
|
.desc = {
|
|
{
|
|
.name = BLOCK_OPT_SIZE,
|
|
.type = QEMU_OPT_SIZE,
|
|
.help = "Virtual disk size"
|
|
},
|
|
{ /* end of list */ }
|
|
}
|
|
};
|
|
|
|
static int ssh_create(const char *filename, QemuOpts *opts, Error **errp)
|
|
{
|
|
int r, ret;
|
|
int64_t total_size = 0;
|
|
QDict *uri_options = NULL;
|
|
BDRVSSHState s;
|
|
ssize_t r2;
|
|
char c[1] = { '\0' };
|
|
|
|
ssh_state_init(&s);
|
|
|
|
/* Get desired file size. */
|
|
total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
|
|
BDRV_SECTOR_SIZE);
|
|
DPRINTF("total_size=%" PRIi64, total_size);
|
|
|
|
uri_options = qdict_new();
|
|
r = parse_uri(filename, uri_options, errp);
|
|
if (r < 0) {
|
|
ret = r;
|
|
goto out;
|
|
}
|
|
|
|
r = connect_to_ssh(&s, uri_options,
|
|
LIBSSH2_FXF_READ|LIBSSH2_FXF_WRITE|
|
|
LIBSSH2_FXF_CREAT|LIBSSH2_FXF_TRUNC,
|
|
0644, errp);
|
|
if (r < 0) {
|
|
ret = r;
|
|
goto out;
|
|
}
|
|
|
|
if (total_size > 0) {
|
|
libssh2_sftp_seek64(s.sftp_handle, total_size-1);
|
|
r2 = libssh2_sftp_write(s.sftp_handle, c, 1);
|
|
if (r2 < 0) {
|
|
sftp_error_setg(errp, &s, "truncate failed");
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
s.attrs.filesize = total_size;
|
|
}
|
|
|
|
ret = 0;
|
|
|
|
out:
|
|
ssh_state_free(&s);
|
|
if (uri_options != NULL) {
|
|
QDECREF(uri_options);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void ssh_close(BlockDriverState *bs)
|
|
{
|
|
BDRVSSHState *s = bs->opaque;
|
|
|
|
ssh_state_free(s);
|
|
}
|
|
|
|
static int ssh_has_zero_init(BlockDriverState *bs)
|
|
{
|
|
BDRVSSHState *s = bs->opaque;
|
|
/* Assume false, unless we can positively prove it's true. */
|
|
int has_zero_init = 0;
|
|
|
|
if (s->attrs.flags & LIBSSH2_SFTP_ATTR_PERMISSIONS) {
|
|
if (s->attrs.permissions & LIBSSH2_SFTP_S_IFREG) {
|
|
has_zero_init = 1;
|
|
}
|
|
}
|
|
|
|
return has_zero_init;
|
|
}
|
|
|
|
static void restart_coroutine(void *opaque)
|
|
{
|
|
Coroutine *co = opaque;
|
|
|
|
DPRINTF("co=%p", co);
|
|
|
|
qemu_coroutine_enter(co);
|
|
}
|
|
|
|
static coroutine_fn void set_fd_handler(BDRVSSHState *s, BlockDriverState *bs)
|
|
{
|
|
int r;
|
|
IOHandler *rd_handler = NULL, *wr_handler = NULL;
|
|
Coroutine *co = qemu_coroutine_self();
|
|
|
|
r = libssh2_session_block_directions(s->session);
|
|
|
|
if (r & LIBSSH2_SESSION_BLOCK_INBOUND) {
|
|
rd_handler = restart_coroutine;
|
|
}
|
|
if (r & LIBSSH2_SESSION_BLOCK_OUTBOUND) {
|
|
wr_handler = restart_coroutine;
|
|
}
|
|
|
|
DPRINTF("s->sock=%d rd_handler=%p wr_handler=%p", s->sock,
|
|
rd_handler, wr_handler);
|
|
|
|
aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
|
|
false, rd_handler, wr_handler, co);
|
|
}
|
|
|
|
static coroutine_fn void clear_fd_handler(BDRVSSHState *s,
|
|
BlockDriverState *bs)
|
|
{
|
|
DPRINTF("s->sock=%d", s->sock);
|
|
aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
|
|
false, NULL, NULL, NULL);
|
|
}
|
|
|
|
/* A non-blocking call returned EAGAIN, so yield, ensuring the
|
|
* handlers are set up so that we'll be rescheduled when there is an
|
|
* interesting event on the socket.
|
|
*/
|
|
static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
|
|
{
|
|
set_fd_handler(s, bs);
|
|
qemu_coroutine_yield();
|
|
clear_fd_handler(s, bs);
|
|
}
|
|
|
|
/* SFTP has a function `libssh2_sftp_seek64' which seeks to a position
|
|
* in the remote file. Notice that it just updates a field in the
|
|
* sftp_handle structure, so there is no network traffic and it cannot
|
|
* fail.
|
|
*
|
|
* However, `libssh2_sftp_seek64' does have a catastrophic effect on
|
|
* performance since it causes the handle to throw away all in-flight
|
|
* reads and buffered readahead data. Therefore this function tries
|
|
* to be intelligent about when to call the underlying libssh2 function.
|
|
*/
|
|
#define SSH_SEEK_WRITE 0
|
|
#define SSH_SEEK_READ 1
|
|
#define SSH_SEEK_FORCE 2
|
|
|
|
static void ssh_seek(BDRVSSHState *s, int64_t offset, int flags)
|
|
{
|
|
bool op_read = (flags & SSH_SEEK_READ) != 0;
|
|
bool force = (flags & SSH_SEEK_FORCE) != 0;
|
|
|
|
if (force || op_read != s->offset_op_read || offset != s->offset) {
|
|
DPRINTF("seeking to offset=%" PRIi64, offset);
|
|
libssh2_sftp_seek64(s->sftp_handle, offset);
|
|
s->offset = offset;
|
|
s->offset_op_read = op_read;
|
|
}
|
|
}
|
|
|
|
static coroutine_fn int ssh_read(BDRVSSHState *s, BlockDriverState *bs,
|
|
int64_t offset, size_t size,
|
|
QEMUIOVector *qiov)
|
|
{
|
|
ssize_t r;
|
|
size_t got;
|
|
char *buf, *end_of_vec;
|
|
struct iovec *i;
|
|
|
|
DPRINTF("offset=%" PRIi64 " size=%zu", offset, size);
|
|
|
|
ssh_seek(s, offset, SSH_SEEK_READ);
|
|
|
|
/* This keeps track of the current iovec element ('i'), where we
|
|
* will write to next ('buf'), and the end of the current iovec
|
|
* ('end_of_vec').
|
|
*/
|
|
i = &qiov->iov[0];
|
|
buf = i->iov_base;
|
|
end_of_vec = i->iov_base + i->iov_len;
|
|
|
|
/* libssh2 has a hard-coded limit of 2000 bytes per request,
|
|
* although it will also do readahead behind our backs. Therefore
|
|
* we may have to do repeated reads here until we have read 'size'
|
|
* bytes.
|
|
*/
|
|
for (got = 0; got < size; ) {
|
|
again:
|
|
DPRINTF("sftp_read buf=%p size=%zu", buf, end_of_vec - buf);
|
|
r = libssh2_sftp_read(s->sftp_handle, buf, end_of_vec - buf);
|
|
DPRINTF("sftp_read returned %zd", r);
|
|
|
|
if (r == LIBSSH2_ERROR_EAGAIN || r == LIBSSH2_ERROR_TIMEOUT) {
|
|
co_yield(s, bs);
|
|
goto again;
|
|
}
|
|
if (r < 0) {
|
|
sftp_error_report(s, "read failed");
|
|
s->offset = -1;
|
|
return -EIO;
|
|
}
|
|
if (r == 0) {
|
|
/* EOF: Short read so pad the buffer with zeroes and return it. */
|
|
qemu_iovec_memset(qiov, got, 0, size - got);
|
|
return 0;
|
|
}
|
|
|
|
got += r;
|
|
buf += r;
|
|
s->offset += r;
|
|
if (buf >= end_of_vec && got < size) {
|
|
i++;
|
|
buf = i->iov_base;
|
|
end_of_vec = i->iov_base + i->iov_len;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static coroutine_fn int ssh_co_readv(BlockDriverState *bs,
|
|
int64_t sector_num,
|
|
int nb_sectors, QEMUIOVector *qiov)
|
|
{
|
|
BDRVSSHState *s = bs->opaque;
|
|
int ret;
|
|
|
|
qemu_co_mutex_lock(&s->lock);
|
|
ret = ssh_read(s, bs, sector_num * BDRV_SECTOR_SIZE,
|
|
nb_sectors * BDRV_SECTOR_SIZE, qiov);
|
|
qemu_co_mutex_unlock(&s->lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int ssh_write(BDRVSSHState *s, BlockDriverState *bs,
|
|
int64_t offset, size_t size,
|
|
QEMUIOVector *qiov)
|
|
{
|
|
ssize_t r;
|
|
size_t written;
|
|
char *buf, *end_of_vec;
|
|
struct iovec *i;
|
|
|
|
DPRINTF("offset=%" PRIi64 " size=%zu", offset, size);
|
|
|
|
ssh_seek(s, offset, SSH_SEEK_WRITE);
|
|
|
|
/* This keeps track of the current iovec element ('i'), where we
|
|
* will read from next ('buf'), and the end of the current iovec
|
|
* ('end_of_vec').
|
|
*/
|
|
i = &qiov->iov[0];
|
|
buf = i->iov_base;
|
|
end_of_vec = i->iov_base + i->iov_len;
|
|
|
|
for (written = 0; written < size; ) {
|
|
again:
|
|
DPRINTF("sftp_write buf=%p size=%zu", buf, end_of_vec - buf);
|
|
r = libssh2_sftp_write(s->sftp_handle, buf, end_of_vec - buf);
|
|
DPRINTF("sftp_write returned %zd", r);
|
|
|
|
if (r == LIBSSH2_ERROR_EAGAIN || r == LIBSSH2_ERROR_TIMEOUT) {
|
|
co_yield(s, bs);
|
|
goto again;
|
|
}
|
|
if (r < 0) {
|
|
sftp_error_report(s, "write failed");
|
|
s->offset = -1;
|
|
return -EIO;
|
|
}
|
|
/* The libssh2 API is very unclear about this. A comment in
|
|
* the code says "nothing was acked, and no EAGAIN was
|
|
* received!" which apparently means that no data got sent
|
|
* out, and the underlying channel didn't return any EAGAIN
|
|
* indication. I think this is a bug in either libssh2 or
|
|
* OpenSSH (server-side). In any case, forcing a seek (to
|
|
* discard libssh2 internal buffers), and then trying again
|
|
* works for me.
|
|
*/
|
|
if (r == 0) {
|
|
ssh_seek(s, offset + written, SSH_SEEK_WRITE|SSH_SEEK_FORCE);
|
|
co_yield(s, bs);
|
|
goto again;
|
|
}
|
|
|
|
written += r;
|
|
buf += r;
|
|
s->offset += r;
|
|
if (buf >= end_of_vec && written < size) {
|
|
i++;
|
|
buf = i->iov_base;
|
|
end_of_vec = i->iov_base + i->iov_len;
|
|
}
|
|
|
|
if (offset + written > s->attrs.filesize)
|
|
s->attrs.filesize = offset + written;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static coroutine_fn int ssh_co_writev(BlockDriverState *bs,
|
|
int64_t sector_num,
|
|
int nb_sectors, QEMUIOVector *qiov)
|
|
{
|
|
BDRVSSHState *s = bs->opaque;
|
|
int ret;
|
|
|
|
qemu_co_mutex_lock(&s->lock);
|
|
ret = ssh_write(s, bs, sector_num * BDRV_SECTOR_SIZE,
|
|
nb_sectors * BDRV_SECTOR_SIZE, qiov);
|
|
qemu_co_mutex_unlock(&s->lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void unsafe_flush_warning(BDRVSSHState *s, const char *what)
|
|
{
|
|
if (!s->unsafe_flush_warning) {
|
|
error_report("warning: ssh server %s does not support fsync",
|
|
s->hostport);
|
|
if (what) {
|
|
error_report("to support fsync, you need %s", what);
|
|
}
|
|
s->unsafe_flush_warning = true;
|
|
}
|
|
}
|
|
|
|
#ifdef HAS_LIBSSH2_SFTP_FSYNC
|
|
|
|
static coroutine_fn int ssh_flush(BDRVSSHState *s, BlockDriverState *bs)
|
|
{
|
|
int r;
|
|
|
|
DPRINTF("fsync");
|
|
again:
|
|
r = libssh2_sftp_fsync(s->sftp_handle);
|
|
if (r == LIBSSH2_ERROR_EAGAIN || r == LIBSSH2_ERROR_TIMEOUT) {
|
|
co_yield(s, bs);
|
|
goto again;
|
|
}
|
|
if (r == LIBSSH2_ERROR_SFTP_PROTOCOL &&
|
|
libssh2_sftp_last_error(s->sftp) == LIBSSH2_FX_OP_UNSUPPORTED) {
|
|
unsafe_flush_warning(s, "OpenSSH >= 6.3");
|
|
return 0;
|
|
}
|
|
if (r < 0) {
|
|
sftp_error_report(s, "fsync failed");
|
|
return -EIO;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static coroutine_fn int ssh_co_flush(BlockDriverState *bs)
|
|
{
|
|
BDRVSSHState *s = bs->opaque;
|
|
int ret;
|
|
|
|
qemu_co_mutex_lock(&s->lock);
|
|
ret = ssh_flush(s, bs);
|
|
qemu_co_mutex_unlock(&s->lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
#else /* !HAS_LIBSSH2_SFTP_FSYNC */
|
|
|
|
static coroutine_fn int ssh_co_flush(BlockDriverState *bs)
|
|
{
|
|
BDRVSSHState *s = bs->opaque;
|
|
|
|
unsafe_flush_warning(s, "libssh2 >= 1.4.4");
|
|
return 0;
|
|
}
|
|
|
|
#endif /* !HAS_LIBSSH2_SFTP_FSYNC */
|
|
|
|
static int64_t ssh_getlength(BlockDriverState *bs)
|
|
{
|
|
BDRVSSHState *s = bs->opaque;
|
|
int64_t length;
|
|
|
|
/* Note we cannot make a libssh2 call here. */
|
|
length = (int64_t) s->attrs.filesize;
|
|
DPRINTF("length=%" PRIi64, length);
|
|
|
|
return length;
|
|
}
|
|
|
|
static BlockDriver bdrv_ssh = {
|
|
.format_name = "ssh",
|
|
.protocol_name = "ssh",
|
|
.instance_size = sizeof(BDRVSSHState),
|
|
.bdrv_parse_filename = ssh_parse_filename,
|
|
.bdrv_file_open = ssh_file_open,
|
|
.bdrv_create = ssh_create,
|
|
.bdrv_close = ssh_close,
|
|
.bdrv_has_zero_init = ssh_has_zero_init,
|
|
.bdrv_co_readv = ssh_co_readv,
|
|
.bdrv_co_writev = ssh_co_writev,
|
|
.bdrv_getlength = ssh_getlength,
|
|
.bdrv_co_flush_to_disk = ssh_co_flush,
|
|
.create_opts = &ssh_create_opts,
|
|
};
|
|
|
|
static void bdrv_ssh_init(void)
|
|
{
|
|
int r;
|
|
|
|
r = libssh2_init(0);
|
|
if (r != 0) {
|
|
fprintf(stderr, "libssh2 initialization failed, %d\n", r);
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
bdrv_register(&bdrv_ssh);
|
|
}
|
|
|
|
block_init(bdrv_ssh_init);
|