Revert my previous change to "-S/--skip" in favour of the two options

"-E/--skip-stderr" and "-S/--skip-stdout".  Both of them support
omitting the number of lines to skip, in which case all output on the
respective file descriptor is skipped.  "--skip" is kept as an alias for
"--skip-stdout" for backwards compatibility with recent releases.

Also, print a message if no (non-skipped) stdout/stderr output is
available.  This fixes a segfault if the remote command prints no
output.


git-svn-id: https://nagiosplug.svn.sourceforge.net/svnroot/nagiosplug/nagiosplug/trunk@1692 f882894a-f735-0410-b71e-b25c423dba1c

2 files changed, 46 insertions, 21 deletions

diff --git a/NEWS b/NEWS
index 6fb2468e..4d458b66 100644
--- a/NEWS
+++ b/NEWS
@@ -2,7 +2,7 @@ This file documents the major additions and syntax changes between releases.
 
 1.4.9 ??
 	Inclusion of contrib/check_cluster2 as check_cluster with some improvements
-	Fix the -S option in check_by_ssh
+	New/improved -E/--skip-stderr and -S/--skip-stdout options for check_by_ssh
 	check_snmp now support Counter64
 
 1.4.8 11th April 2007
diff --git a/plugins/check_by_ssh.c b/plugins/check_by_ssh.c
index 65eee3c5..6855ebc0 100644
--- a/plugins/check_by_ssh.c
+++ b/plugins/check_by_ssh.c
@@ -48,7 +48,8 @@ void print_usage (void);
 
 unsigned int commands = 0;
 unsigned int services = 0;
-unsigned int skip = 0;
+int skip_stdout = 0;
+int skip_stderr = 0;
 char *remotecmd = NULL;
 char *comm = NULL;
 char *hostname = NULL;
@@ -92,18 +93,27 @@ main (int argc, char **argv)
 		printf ("%s\n", comm);
 
 	result = np_runcmd(comm, &chld_out, &chld_err, 0);
+
+	if (skip_stdout == -1) /* --skip-stdout specified without argument */
+		skip_stdout = chld_out.lines;
+	if (skip_stderr == -1) /* --skip-stderr specified without argument */
+		skip_stderr = chld_err.lines;
+
 	/* UNKNOWN if (non-skipped) output found on stderr */
-	if((signed)chld_err.lines - (signed)skip > 0) {
-		printf(_("Remote command execution failed: %s\n"),
-		       skip < chld_err.lines ? chld_err.line[skip] : chld_err.buf);
+	if(chld_err.lines > skip_stderr) {
+		printf (_("Remote command execution failed: %s\n"),
+		        chld_err.line[skip_stderr]);
 		return STATE_UNKNOWN;
 	}
-	skip -= chld_err.lines;
 
 	/* this is simple if we're not supposed to be passive.
 	 * Wrap up quickly and keep the tricks below */
 	if(!passive) {
-		printf ("%s\n", skip < chld_out.lines ? chld_out.line[skip] : chld_out.buf);
+		if (chld_out.lines > skip_stdout)
+			puts (chld_out.line[skip_stdout]);
+		else
+			printf (_("%s - check_by_ssh: Remote command '%s' returned status %d\n"),
+			        state_text(result), remotecmd, result);
 		return result; 	/* return error status from remote command */
 	}
 
@@ -120,7 +130,7 @@ main (int argc, char **argv)
 
 	local_time = time (NULL);
 	commands = 0;
-	for(i = skip; chld_out.line[i]; i++) {
+	for(i = skip_stdout; i < chld_out.lines; i++) {
 		status_text = strstr (chld_out.line[i], "STATUS CODE: ");
 		if (status_text == NULL) {
 			printf ("%s", chld_out.line[i]);
@@ -162,7 +172,9 @@ process_arguments (int argc, char **argv)
 		{"user", required_argument, 0, 'u'},
 		{"logname", required_argument, 0, 'l'},
 		{"command", required_argument, 0, 'C'},
-		{"skip", required_argument, 0, 'S'},
+		{"skip", optional_argument, 0, 'S'}, /* backwards compatibility */
+		{"skip-stdout", optional_argument, 0, 'S'},
+		{"skip-stderr", optional_argument, 0, 'E'},
 		{"proto1", no_argument, 0, '1'},
 		{"proto2", no_argument, 0, '2'},
 		{"use-ipv4", no_argument, 0, '4'},
@@ -180,7 +192,7 @@ process_arguments (int argc, char **argv)
 			strcpy (argv[c], "-t");
 
 	while (1) {
-		c = getopt_long (argc, argv, "Vvh1246fqt:H:O:p:i:u:l:C:S:n:s:o:", longopts,
+		c = getopt_long (argc, argv, "Vvh1246fqt:H:O:p:i:u:l:C:S::E::n:s:o:", longopts,
 		                 &option);
 
 		if (c == -1 || c == EOF)
@@ -250,11 +262,21 @@ process_arguments (int argc, char **argv)
 				asprintf (&remotecmd, "%s;echo STATUS CODE: $?;", remotecmd);
 			asprintf (&remotecmd, "%s%s", remotecmd, optarg);
 			break;
-		case 'S':									/* Skip n lines in the output to ignore system banner */
-			if (!is_integer (optarg))
-				usage_va(_("skip lines must be an integer"));
+		case 'S':									/* skip n (or all) lines on stdout */
+			if (optarg == NULL)
+				skip_stdout = -1; /* skip all output on stdout */
+			else if (!is_integer (optarg))
+				usage_va(_("skip-stdout argument must be an integer"));
+			else
+				skip_stdout = atoi (optarg);
+			break;
+		case 'E':									/* skip n (or all) lines on stderr */
+			if (optarg == NULL)
+				skip_stderr = -1; /* skip all output on stderr */
+			else if (!is_integer (optarg))
+				usage_va(_("skip-stderr argument must be an integer"));
 			else
-				skip = atoi (optarg);
+				skip_stderr = atoi (optarg);
 			break;
 		case 'o':									/* Extra options for the ssh command */
 			asprintf (&comm, "%s -%c '%s'", comm, c, optarg);
@@ -334,13 +356,15 @@ print_help (void)
 	printf (_(UT_IPv46));
 
   printf (" %s\n", "-1, --proto1");
-  printf ("    %s\n", _("tell ssh to use Protocol 1"));
+  printf ("    %s\n", _("tell ssh to use Protocol 1 [optional]"));
   printf (" %s\n", "-2, --proto2");
-  printf ("    %s\n", _("tell ssh to use Protocol 2"));
-  printf (" %s\n", "-S, --skip=n");
-  printf ("    %s\n", _("Ignore first n lines on STDERR (to suppress a logon banner)"));
+  printf ("    %s\n", _("tell ssh to use Protocol 2 [optional]"));
+  printf (" %s\n", "-S, --skip-stdout[=n]");
+  printf ("    %s\n", _("Ignore all or (if specified) first n lines on STDOUT [optional]"));
+  printf (" %s\n", "-E, --skip-stderr[=n]");
+  printf ("    %s\n", _("Ignore all or (if specified) first n lines on STDERR [optional]"));
   printf (" %s\n", "-f");
-  printf ("    %s\n", _("tells ssh to fork rather than create a tty"));
+  printf ("    %s\n", _("tells ssh to fork rather than create a tty [optional]"));
   printf (" %s\n","-C, --command='COMMAND STRING'");
   printf ("    %s\n", _("command to execute on the remote machine"));
   printf (" %s\n","-l, --logname=USERNAME");
@@ -385,7 +409,8 @@ print_usage (void)
 {
 	printf (_("Usage:"));
 	printf (" %s -H <host> -C <command> [-fq] [-1|-2] [-4|-6]\n"
-	        "       [-S lines] [-t timeout] [-i identity] [-l user] [-n name]\n"
-	        "       [-s servicelist] [-O outputfile] [-p port] [-o ssh-option]\n",
+	        "       [-S [lines]] [-E [lines]] [-t timeout] [-i identity]\n"
+	        "       [-l user] [-n name] [-s servicelist] [-O outputfile]\n"
+	        "       [-p port] [-o ssh-option]\n",
 	        progname);
 }