[Qemu-devel] [PATCH 2/4] configure: Avoid using libssh deprecated API

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

The libssh packaged by a distribution can predate version 0.8,
but still provides the newer API introduced after version 0.7.

Using the deprecated API leads to build failure, as on Ubuntu 18.04:

    CC      block/ssh.o
  block/ssh.c: In function 'check_host_key_hash':
  block/ssh.c:444:5: error: 'ssh_get_publickey' is deprecated [-Werror=deprecated-declarations]
       r = ssh_get_publickey(s->session, &pubkey);
       ^
  In file included from block/ssh.c:27:0:
  /usr/include/libssh/libssh.h:489:31: note: declared here
   SSH_DEPRECATED LIBSSH_API int ssh_get_publickey(ssh_session session, ssh_key *key);
                                 ^~~~~~~~~~~~~~~~~
  rules.mak:69: recipe for target 'block/ssh.o' failed
  make: *** [block/ssh.o] Error 1

Fix by using the newer API if available.

Suggested-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 block/ssh.c | 2 +-
 configure   | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/block/ssh.c b/block/ssh.c
index 501933b855..f5fea921c6 100644
--- a/block/ssh.c
+++ b/block/ssh.c
@@ -438,7 +438,7 @@ check_host_key_hash(BDRVSSHState *s, const char *hash,
     unsigned char *server_hash;
     size_t server_hash_len;
 
-#ifdef HAVE_LIBSSH_0_8
+#ifdef HAVE_SSH_GET_SERVER_PUBLICKEY
     r = ssh_get_server_publickey(s->session, &pubkey);
 #else
     r = ssh_get_publickey(s->session, &pubkey);
diff --git a/configure b/configure
index 1d5c07de1f..fe3fef9309 100755
--- a/configure
+++ b/configure
@@ -3949,11 +3949,18 @@ fi
 if test "$libssh" = "yes"; then
   cat > $TMPC <<EOF
 #include <libssh/libssh.h>
+#ifdef HAVE_SSH_GET_SERVER_PUBLICKEY
 int main(void) { return ssh_get_server_publickey(NULL, NULL); }
+#else
+int main(void) { return ssh_get_publickey(NULL, NULL); }
+#endif
 EOF
   if compile_object "$libssh_cflags"; then
     libssh_cflags="-DHAVE_LIBSSH_0_8 $libssh_cflags"
   fi
+  if compile_object "$libssh_cflags -DHAVE_SSH_GET_SERVER_PUBLICKEY"; then
+    libssh_cflags="-DHAVE_SSH_GET_SERVER_PUBLICKEY $libssh_cflags"
+  fi
 fi
 
 ##########################################
-- 
2.20.1