[monitoring-plugins] check_by_ssh: do not incorrectly assume that ssh ...

[Lorenz Kästle]

 Module: monitoring-plugins
 Branch: master
 Commit: 62242ddcf5caa09eee79c15a94a5d861b9be95c8
 Author: Lorenz Kästle <12514511+rincewinds...@users.noreply.github.com>
   Date: Sun Nov 16 15:27:19 2025 +0100
    URL: 
https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=62242ddc

check_by_ssh: do not incorrectly assume that ssh (1) succeeded

---

 plugins/check_by_ssh.c | 23 ++---------------------
 1 file changed, 2 insertions(+), 21 deletions(-)

diff --git a/plugins/check_by_ssh.c b/plugins/check_by_ssh.c
index 8036ffa4..ebe54b80 100644
--- a/plugins/check_by_ssh.c
+++ b/plugins/check_by_ssh.c
@@ -94,37 +94,18 @@ int main(int argc, char **argv) {
        mp_check overall = mp_check_init();
 
        /* SSH returns 255 if connection attempt fails; include the first line 
of error output */
-       mp_subcheck sc_ssh_execution = mp_subcheck_init();
+       // we can sadly not detect other SSH errors
        if (child_result.cmd_error_code == 255 && config.unknown_timeout) {
+               mp_subcheck sc_ssh_execution = mp_subcheck_init();
                xasprintf(&sc_ssh_execution.output, "SSH connection failed: %s",
                                  child_result.stderr.lines > 0 ? 
child_result.stderr.line[0]
                                                                                
                : "(no error output)");
 
-               sc_ssh_execution = mp_set_subcheck_state(sc_ssh_execution, 
STATE_UNKNOWN);
-               mp_add_subcheck_to_check(&overall, sc_ssh_execution);
-               mp_exit(overall);
-       } else if (child_result.cmd_error_code != 0) {
-               xasprintf(&sc_ssh_execution.output, "SSH connection failed: ");
-
-               if (child_result.stderr.lines > 0) {
-                       for (size_t i = 0; i < child_result.stderr.lines; i++) {
-                               xasprintf(&sc_ssh_execution.output, "%s\n%s", 
sc_ssh_execution.output,
-                                                 child_result.stderr.line[i]);
-                       }
-               } else {
-                       xasprintf(&sc_ssh_execution.output, "%s %s", 
sc_ssh_execution.output,
-                                         "no output on stderr");
-               }
-
                sc_ssh_execution = mp_set_subcheck_state(sc_ssh_execution, 
STATE_UNKNOWN);
                mp_add_subcheck_to_check(&overall, sc_ssh_execution);
                mp_exit(overall);
        }
 
-       xasprintf(&sc_ssh_execution.output, "SSH connection succeeded");
-       sc_ssh_execution = mp_set_subcheck_state(sc_ssh_execution, STATE_OK);
-       mp_add_subcheck_to_check(&overall, sc_ssh_execution);
-
        if (verbose) {
                for (size_t i = 0; i < child_result.stdout.lines; i++) {
                        printf("stdout: %s\n", child_result.stdout.line[i]);