check_tcp: Properly deal will partial recv(3)s

The np_expect_match() function now returns one of three possible states
instead of just TRUE or FALSE:

- NP_MATCH_SUCCESS
- NP_MATCH_FAILURE
- NP_MATCH_RETRY

The NP_MATCH_RETRY state indicates that matching might succeed if
np_expect_match() is called with a longer input string.  This allows
check_tcp to decide whether it makes sense to wait for additional data
from the server.

1 files changed, 16 insertions, 11 deletions

diff --git a/plugins/check_tcp.c b/plugins/check_tcp.c
index e8d7ec6..517b6b5 100644
--- a/plugins/check_tcp.c
+++ b/plugins/check_tcp.c
@@ -3,7 +3,7 @@
 * Nagios check_tcp plugin
 *
 * License: GPL
-* Copyright (c) 1999-2008 Nagios Plugins Development Team
+* Copyright (c) 1999-2013 Nagios Plugins Development Team
 *
 * Description:
 *
@@ -277,25 +277,30 @@ main (int argc, char **argv)
                         status = realloc(status, len + i + 1);
                         memcpy(&status[len], buffer, i);
                         len += i;
+                        status[len] = '\0';
 
                         /* stop reading if user-forced */
                         if (maxbytes && len >= maxbytes)
                                 break;
+
+                        if ((match = np_expect_match(status,
+                            server_expect,
+                            server_expect_count,
+                            match_flags)) != NP_MATCH_RETRY)
+                                break;
                 }
 
                 /* no data when expected, so return critical */
                 if (len == 0)
                         die (STATE_CRITICAL, _("No data received from host\n"));
 
-                /* force null-termination and strip whitespace from end of output */
-                status[len--] = '\0';
                 /* print raw output if we're debugging */
                 if(flags & FLAG_VERBOSE)
                         printf("received %d bytes from host\n#-raw-recv-------#\n%s\n#-raw-recv-------#\n",
                                (int)len + 1, status);
-                while(isspace(status[len])) status[len--] = '\0';
-
-                match = np_expect_match(status, server_expect, server_expect_count, match_flags);
+                /* strip whitespace from end of output */
+                while(--len > 0 && isspace(status[len]))
+                        status[len] = '\0';
         }
 
         if (server_quit != NULL) {
@@ -315,7 +320,7 @@ main (int argc, char **argv)
                 result = STATE_WARNING;
 
         /* did we get the response we hoped? */
-        if(match == FALSE && result != STATE_CRITICAL)
+        if(match != NP_MATCH_SUCCESS && result != STATE_CRITICAL)
                 result = expect_mismatch_state;
 
         /* reset the alarm */
@@ -326,10 +331,10 @@ main (int argc, char **argv)
          * the response we were looking for. if-else */
         printf("%s %s - ", SERVICE, state_text(result));
 
-        if(match == FALSE && len && !(flags & FLAG_HIDE_OUTPUT))
+        if(match != NP_MATCH_SUCCESS && len && !(flags & FLAG_HIDE_OUTPUT))
                 printf("Unexpected response from host/socket: %s", status);
         else {
-                if(match == FALSE)
+                if(match != NP_MATCH_SUCCESS)
                         printf("Unexpected response from host/socket on ");
                 else
                         printf("%.3f second response time on ", elapsed_time);
@@ -339,13 +344,13 @@ main (int argc, char **argv)
                         printf("socket %s", server_address);
         }
 
-        if (match != FALSE && !(flags & FLAG_HIDE_OUTPUT) && len)
+        if (match == NP_MATCH_SUCCESS && !(flags & FLAG_HIDE_OUTPUT) && len)
                 printf (" [%s]", status);
 
         /* perf-data doesn't apply when server doesn't talk properly,
          * so print all zeroes on warn and crit. Use fperfdata since
          * localisation settings can make different outputs */
-        if(match == FALSE)
+        if(match != NP_MATCH_SUCCESS)
                 printf ("|%s",
                                 fperfdata ("time", elapsed_time, "s",
                                 (flags & FLAG_TIME_WARN ? TRUE : FALSE), 0,