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check_tcp: Properly deal will partial recv(3)s
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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.
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@weiss
weiss committed Sep 12, 2013
1 parent 6629972 commit e804471
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Showing 4 changed files with 74 additions and 38 deletions.
20 changes: 11 additions & 9 deletions lib/tests/test_tcp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,29 +25,31 @@ main (int argc, char **argv)
{
char** server_expect;
int server_expect_count = 3;
plan_tests(8);
plan_tests(9);

server_expect = malloc(sizeof(char*) * server_expect_count);

server_expect[0] = strdup("AA");
server_expect[1] = strdup("bb");
server_expect[2] = strdup("CC");

ok(np_expect_match("AA bb CC XX", server_expect, server_expect_count, NP_MATCH_EXACT) == TRUE,
ok(np_expect_match("AA bb CC XX", server_expect, server_expect_count, NP_MATCH_EXACT) == NP_MATCH_SUCCESS,
"Test matching any string at the beginning (first expect string)");
ok(np_expect_match("bb AA CC XX", server_expect, server_expect_count, NP_MATCH_EXACT) == TRUE,
ok(np_expect_match("bb AA CC XX", server_expect, server_expect_count, NP_MATCH_EXACT) == NP_MATCH_SUCCESS,
"Test matching any string at the beginning (second expect string)");
ok(np_expect_match("XX bb AA CC XX", server_expect, server_expect_count, NP_MATCH_EXACT) == FALSE,
ok(np_expect_match("b", server_expect, server_expect_count, NP_MATCH_EXACT) == NP_MATCH_RETRY,
"Test matching any string at the beginning (substring match)");
ok(np_expect_match("XX bb AA CC XX", server_expect, server_expect_count, NP_MATCH_EXACT) == NP_MATCH_FAILURE,
"Test with strings not matching at the beginning");
ok(np_expect_match("XX CC XX", server_expect, server_expect_count, NP_MATCH_EXACT) == FALSE,
ok(np_expect_match("XX CC XX", server_expect, server_expect_count, NP_MATCH_EXACT) == NP_MATCH_FAILURE,
"Test matching any string");
ok(np_expect_match("XX", server_expect, server_expect_count, 0) == FALSE,
ok(np_expect_match("XX", server_expect, server_expect_count, 0) == NP_MATCH_RETRY,
"Test not matching any string");
ok(np_expect_match("XX AA bb CC XX", server_expect, server_expect_count, NP_MATCH_ALL) == TRUE,
ok(np_expect_match("XX AA bb CC XX", server_expect, server_expect_count, NP_MATCH_ALL) == NP_MATCH_SUCCESS,
"Test matching all strings");
ok(np_expect_match("XX bb CC XX", server_expect, server_expect_count, NP_MATCH_ALL) == FALSE,
ok(np_expect_match("XX bb CC XX", server_expect, server_expect_count, NP_MATCH_ALL) == NP_MATCH_RETRY,
"Test not matching all strings");
ok(np_expect_match("XX XX", server_expect, server_expect_count, NP_MATCH_ALL) == FALSE,
ok(np_expect_match("XX XX", server_expect, server_expect_count, NP_MATCH_ALL) == NP_MATCH_RETRY,
"Test not matching any string (testing all)");


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47 changes: 31 additions & 16 deletions lib/utils_tcp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@
* Library for check_tcp
*
* License: GPL
* Copyright (c) 1999-2007 Nagios Plugins Development Team
* Copyright (c) 1999-2013 Nagios Plugins Development Team
*
* Description:
*
Expand All @@ -29,29 +29,44 @@
#include "common.h"
#include "utils_tcp.h"

int
#define VERBOSE(message) \
do { \
if (flags & NP_MATCH_VERBOSE) \
puts(message); \
} while (0)

enum np_match_result
np_expect_match(char* status, char** server_expect, int expect_count, int flags)
{
int match = 0;
int i;
int i, match = 0, partial = 0;
for (i = 0; i < expect_count; i++) {
if (flags & NP_MATCH_VERBOSE)
printf ("looking for [%s] %s [%s]\n", server_expect[i],
(flags & NP_MATCH_EXACT) ? "in beginning of" : "anywhere in",
status);

if ((flags & NP_MATCH_EXACT &&
!strncmp(status, server_expect[i], strlen(server_expect[i]))) ||
(!(flags & NP_MATCH_EXACT) && strstr(status, server_expect[i])))
{
if(flags & NP_MATCH_VERBOSE) puts("found it");
match += 1;
} else
if(flags & NP_MATCH_VERBOSE) puts("couldn't find it");
if (flags & NP_MATCH_EXACT) {
if (strncmp(status, server_expect[i], strlen(server_expect[i])) == 0) {
VERBOSE("found it");
match++;
continue;
} else if (strncmp(status, server_expect[i], strlen(status)) == 0) {
VERBOSE("found a substring");
partial++;
continue;
}
} else if (strstr(status, server_expect[i]) != NULL) {
VERBOSE("found it");
match++;
continue;
}
VERBOSE("couldn't find it");
}
if ((flags & NP_MATCH_ALL && match == expect_count) ||
(!(flags & NP_MATCH_ALL) && match >= 1)) {
return TRUE;
} else
return FALSE;
(!(flags & NP_MATCH_ALL) && match >= 1))
return NP_MATCH_SUCCESS;
else if (partial > 0 || !(flags & NP_MATCH_EXACT))
return NP_MATCH_RETRY;
else
return NP_MATCH_FAILURE;
}
18 changes: 16 additions & 2 deletions lib/utils_tcp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -4,5 +4,19 @@
#define NP_MATCH_EXACT 0x2
#define NP_MATCH_VERBOSE 0x4

int np_expect_match(char* status, char** server_expect, int server_expect_count,
int flags);
/*
* The NP_MATCH_RETRY state indicates that matching might succeed if
* np_expect_match() is called with a longer input string. This allows the
* caller to decide whether it makes sense to wait for additional data from the
* server.
*/
enum np_match_result {
NP_MATCH_FAILURE,
NP_MATCH_SUCCESS,
NP_MATCH_RETRY
};

enum np_match_result np_expect_match(char *status,
char **server_expect,
int server_expect_count,
int flags);
27 changes: 16 additions & 11 deletions plugins/check_tcp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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:
*
Expand Down Expand Up @@ -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) {
Expand All @@ -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 */
Expand All @@ -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);
Expand All @@ -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,
Expand Down

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