ssh: switch from libssh2 to libssh

Rewrite the implementation of the ssh block driver to use libssh instead
of libssh2.  The libssh library has various advantages over libssh2:
- easier API for authentication (for example for using ssh-agent)
- easier API for known_hosts handling
- supports newer types of keys in known_hosts

Use APIs/features available in libssh 0.8 conditionally, to support
older versions (which are not recommended though).

Adjust the iotest 207 according to the different error message, and to
find the default key type for localhost (to properly compare the
fingerprint with).
Contributed-by: Max Reitz <mreitz@redhat.com>

Adjust the various Docker/Travis scripts to use libssh when available
instead of libssh2. The mingw/mxe testing is dropped for now, as there
are no packages for it.

Signed-off-by: Pino Toscano <ptoscano@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20190620200840.17655-1-ptoscano@redhat.com
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 5873173.t2JhDm7DL7@lindworm.usersys.redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

1 files changed, 8 insertions, 6 deletions

diff --git a/block/trace-events b/block/trace-events
index 9ccea75..d724df0 100644
--- a/block/trace-events
+++ b/block/trace-events
@@ -171,19 +171,21 @@ nbd_client_connect_success(const char *export_name) "export '%s'"
 # ssh.c
 ssh_restart_coroutine(void *co) "co=%p"
 ssh_flush(void) "fsync"
-ssh_check_host_key_knownhosts(const char *key) "host key OK: %s"
+ssh_check_host_key_knownhosts(void) "host key OK"
 ssh_connect_to_ssh(char *path, int flags, int mode) "opening file %s flags=0x%x creat_mode=0%o"
 ssh_co_yield(int sock, void *rd_handler, void *wr_handler) "s->sock=%d rd_handler=%p wr_handler=%p"
 ssh_co_yield_back(int sock) "s->sock=%d - back"
 ssh_getlength(int64_t length) "length=%" PRIi64
 ssh_co_create_opts(uint64_t size) "total_size=%" PRIu64
 ssh_read(int64_t offset, size_t size) "offset=%" PRIi64 " size=%zu"
-ssh_read_buf(void *buf, size_t size) "sftp_read buf=%p size=%zu"
-ssh_read_return(ssize_t ret) "sftp_read returned %zd"
+ssh_read_buf(void *buf, size_t size, size_t actual_size) "sftp_read buf=%p size=%zu (actual size=%zu)"
+ssh_read_return(ssize_t ret, int sftp_err) "sftp_read returned %zd (sftp error=%d)"
 ssh_write(int64_t offset, size_t size) "offset=%" PRIi64 " size=%zu"
-ssh_write_buf(void *buf, size_t size) "sftp_write buf=%p size=%zu"
-ssh_write_return(ssize_t ret) "sftp_write returned %zd"
+ssh_write_buf(void *buf, size_t size, size_t actual_size) "sftp_write buf=%p size=%zu (actual size=%zu)"
+ssh_write_return(ssize_t ret, int sftp_err) "sftp_write returned %zd (sftp error=%d)"
 ssh_seek(int64_t offset) "seeking to offset=%" PRIi64
+ssh_auth_methods(int methods) "auth methods=0x%x"
+ssh_server_status(int status) "server status=%d"
 
 # curl.c
 curl_timer_cb(long timeout_ms) "timer callback timeout_ms %ld"
@@ -216,4 +218,4 @@ sheepdog_snapshot_create(const char *sn_name, const char *id) "%s %s"
 sheepdog_snapshot_create_inode(const char *name, uint32_t snap, uint32_t vdi) "s->inode: name %s snap_id 0x%" PRIx32 " vdi 0x%" PRIx32
 
 # ssh.c
-sftp_error(const char *op, const char *ssh_err, int ssh_err_code, unsigned long sftp_err_code) "%s failed: %s (libssh2 error code: %d, sftp error code: %lu)"
+sftp_error(const char *op, const char *ssh_err, int ssh_err_code, int sftp_err_code) "%s failed: %s (libssh error code: %d, sftp error code: %d)"