From 4621427ba8cbfab4815e65d35a728ad51ad8c391 Mon Sep 17 00:00:00 2001 From: rincewind Date: Sat, 25 Sep 2021 23:24:45 +0200 Subject: check_swap: Fix perfdata und thresholds for big values and simplify code The original problem was https://github.com/monitoring-plugins/monitoring-plugins/pull/1705 where the performance data output of check_swap did not conform to the parser logic of a monitoring system (which decided to go for "correct" SI or IEC units. The PR was accompanied by a change to byte values in the performance data which broke the _perfdata_ helper function which could not handle values of this size. The fix for this, was to use _fperfdata_ which could, but would use float values. I didn't like that (since all values here are discreet) and this is my proposal for a fix for the problem. It introduces some helper functions which do now explicitely work with (u)int64_t, including a special version of the _perfdata_ helper. In the process of introducing this to check_swap, I stumbled over several sections of the check_swap code which I found problematic. Therefore I tried to simplify the code and make it more readable and less redundant. I am kinda sorry about this, but sincerely hope my changes can be helpful. --- plugins/check_swap.c | 239 +++++++++++++++++++++++++++++---------------------- 1 file changed, 137 insertions(+), 102 deletions(-) (limited to 'plugins') diff --git a/plugins/check_swap.c b/plugins/check_swap.c index 0ff0c770..25bcb3d5 100644 --- a/plugins/check_swap.c +++ b/plugins/check_swap.c @@ -34,6 +34,10 @@ const char *email = "devel@monitoring-plugins.org"; #include "common.h" #include "popen.h" #include "utils.h" +#include +#include +#include +#include #ifdef HAVE_DECL_SWAPCTL # ifdef HAVE_SYS_PARAM_H @@ -51,26 +55,30 @@ const char *email = "devel@monitoring-plugins.org"; # define SWAP_CONVERSION 1 #endif -int check_swap (int usp, float free_swap_mb, float total_swap_mb); +typedef struct { + bool is_percentage; + uint64_t value; +} threshold_t; + +int check_swap (float free_swap_mb, float total_swap_mb); int process_arguments (int argc, char **argv); int validate_arguments (void); void print_usage (void); void print_help (void); -int warn_percent = 0; -int crit_percent = 0; -float warn_size_bytes = 0; -float crit_size_bytes = 0; +threshold_t warn; +threshold_t crit; int verbose; -int allswaps; +bool allswaps; int no_swap_state = STATE_CRITICAL; int main (int argc, char **argv) { - int percent_used, percent; - float total_swap_mb = 0, used_swap_mb = 0, free_swap_mb = 0; - float dsktotal_mb = 0, dskused_mb = 0, dskfree_mb = 0, tmp_mb = 0; + unsigned int percent_used, percent; + uint64_t total_swap_mb = 0, used_swap_mb = 0, free_swap_mb = 0; + uint64_t dsktotal_mb = 0, dskused_mb = 0, dskfree_mb = 0; + uint64_t tmp_KB = 0; int result = STATE_UNKNOWN; char input_buffer[MAX_INPUT_BUFFER]; #ifdef HAVE_PROC_MEMINFO @@ -116,10 +124,15 @@ main (int argc, char **argv) } fp = fopen (PROC_MEMINFO, "r"); while (fgets (input_buffer, MAX_INPUT_BUFFER - 1, fp)) { - if (sscanf (input_buffer, "%*[S]%*[w]%*[a]%*[p]%*[:] %f %f %f", &dsktotal_mb, &dskused_mb, &dskfree_mb) == 3) { - dsktotal_mb = dsktotal_mb / 1048576; /* Apply conversion */ - dskused_mb = dskused_mb / 1048576; - dskfree_mb = dskfree_mb / 1048576; + /* + * The following sscanf call looks for a line looking like: "Swap: 123 123 123" + * On which kind of system this format exists, I can not say, but I wanted to + * document this for people who are not adapt with sscanf anymore, like me + */ + if (sscanf (input_buffer, "%*[S]%*[w]%*[a]%*[p]%*[:] %lu %lu %lu", &dsktotal_mb, &dskused_mb, &dskfree_mb) == 3) { + dsktotal_mb = dsktotal_mb / (1024 * 1024); /* Apply conversion */ + dskused_mb = dskused_mb / (1024 * 1024); + dskfree_mb = dskfree_mb / (1024 * 1024); total_swap_mb += dsktotal_mb; used_swap_mb += dskused_mb; free_swap_mb += dskfree_mb; @@ -128,21 +141,25 @@ main (int argc, char **argv) percent=100.0; else percent = 100 * (((double) dskused_mb) / ((double) dsktotal_mb)); - result = max_state (result, check_swap (percent, dskfree_mb, dsktotal_mb)); + result = max_state (result, check_swap (dskfree_mb, dsktotal_mb)); if (verbose) xasprintf (&status, "%s [%.0f (%d%%)]", status, dskfree_mb, 100 - percent); } } - else if (sscanf (input_buffer, "%*[S]%*[w]%*[a]%*[p]%[TotalFre]%*[:] %f %*[k]%*[B]", str, &tmp_mb)) { + /* + * The following sscanf call looks for lines looking like: "SwapTotal: 123" and "SwapFree: 123" + * This format exists at least on Debian Linux with a 5.* kernel + */ + else if (sscanf (input_buffer, "%*[S]%*[w]%*[a]%*[p]%[TotalFre]%*[:] %lu %*[k]%*[B]", str, &tmp_KB)) { if (verbose >= 3) { - printf("Got %s with %f\n", str, tmp_mb); + printf("Got %s with %lu\n", str, tmp_KB); } /* I think this part is always in Kb, so convert to mb */ if (strcmp ("Total", str) == 0) { - dsktotal_mb = tmp_mb / 1024; + dsktotal_mb = tmp_KB / 1024; } else if (strcmp ("Free", str) == 0) { - dskfree_mb = tmp_mb / 1024; + dskfree_mb = tmp_KB / 1024; } } } @@ -227,7 +244,7 @@ main (int argc, char **argv) free_swap_mb += dskfree_mb; if (allswaps) { percent = 100 * (((double) dskused_mb) / ((double) dsktotal_mb)); - result = max_state (result, check_swap (percent, dskfree_mb, dsktotal_mb)); + result = max_state (result, check_swap (dskfree_mb, dsktotal_mb)); if (verbose) xasprintf (&status, "%s [%.0f (%d%%)]", status, dskfree_mb, 100 - percent); } @@ -289,7 +306,7 @@ main (int argc, char **argv) if(allswaps && dsktotal_mb > 0){ percent = 100 * (((double) dskused_mb) / ((double) dsktotal_mb)); - result = max_state (result, check_swap (percent, dskfree_mb, dsktotal_mb)); + result = max_state (result, check_swap (dskfree_mb, dsktotal_mb)); if (verbose) { xasprintf (&status, "%s [%.0f (%d%%)]", status, dskfree_mb, 100 - percent); } @@ -328,7 +345,7 @@ main (int argc, char **argv) if(allswaps && dsktotal_mb > 0){ percent = 100 * (((double) dskused_mb) / ((double) dsktotal_mb)); - result = max_state (result, check_swap (percent, dskfree_mb, dsktotal_mb)); + result = max_state (result, check_swap(dskfree_mb, dsktotal_mb)); if (verbose) { xasprintf (&status, "%s [%.0f (%d%%)]", status, dskfree_mb, 100 - percent); } @@ -355,14 +372,19 @@ main (int argc, char **argv) status = "- Swap is either disabled, not present, or of zero size. "; } - result = max_state (result, check_swap (percent_used, free_swap_mb, total_swap_mb)); - printf (_("SWAP %s - %d%% free (%d MB out of %d MB) %s|"), + result = max_state (result, check_swap(free_swap_mb, total_swap_mb)); + printf (_("SWAP %s - %d%% free (%dMB out of %dMB) %s|"), state_text (result), (100 - percent_used), (int) free_swap_mb, (int) total_swap_mb, status); - puts (perfdata ("swap", (long) free_swap_mb, "MB", - TRUE, (long) max (warn_size_bytes/(1024 * 1024), warn_percent/100.0*total_swap_mb), - TRUE, (long) max (crit_size_bytes/(1024 * 1024), crit_percent/100.0*total_swap_mb), + uint64_t warn_print = warn.value; + if (warn.is_percentage) warn_print = warn.value * (total_swap_mb *1024 *1024/100); + uint64_t crit_print = crit.value; + if (crit.is_percentage) crit_print = crit.value * (total_swap_mb *1024 *1024/100); + + puts (perfdata_uint64 ("swap", free_swap_mb *1024 *1024, "B", + TRUE, warn_print, + TRUE, crit_print, TRUE, 0, TRUE, (long) total_swap_mb)); @@ -370,26 +392,37 @@ main (int argc, char **argv) } - int -check_swap (int usp, float free_swap_mb, float total_swap_mb) +check_swap(float free_swap_mb, float total_swap_mb) { if (!total_swap_mb) return no_swap_state; - int result = STATE_UNKNOWN; - float free_swap = free_swap_mb * (1024 * 1024); /* Convert back to bytes as warn and crit specified in bytes */ - if (usp >= 0 && crit_percent != 0 && usp >= (100.0 - crit_percent)) - result = STATE_CRITICAL; - else if (crit_size_bytes > 0 && free_swap <= crit_size_bytes) - result = STATE_CRITICAL; - else if (usp >= 0 && warn_percent != 0 && usp >= (100.0 - warn_percent)) - result = STATE_WARNING; - else if (warn_size_bytes > 0 && free_swap <= warn_size_bytes) - result = STATE_WARNING; - else if (usp >= 0.0) - result = STATE_OK; - return result; + uint64_t free_swap = free_swap_mb * (1024 * 1024); /* Convert back to bytes as warn and crit specified in bytes */ + + if (!crit.is_percentage && crit.value <= free_swap) return STATE_CRITICAL; + if (!warn.is_percentage && warn.value <= free_swap) return STATE_WARNING; + + + uint64_t usage_percentage = ((total_swap_mb - free_swap_mb) / total_swap_mb) * 100; + + if (crit.is_percentage && + usage_percentage >= 0 && + crit.value != 0 && + usage_percentage >= (100 - crit.value)) + { + return STATE_CRITICAL; + } + + if (warn.is_percentage && + usage_percentage >= 0 && + warn.value != 0 && + usage_percentage >= (100 - warn.value)) + { + return STATE_WARNING; + } + + return STATE_OK; } @@ -422,42 +455,67 @@ process_arguments (int argc, char **argv) break; switch (c) { - case 'w': /* warning size threshold */ - if (is_intnonneg (optarg)) { - warn_size_bytes = (float) atoi (optarg); - break; - } - else if (strstr (optarg, ",") && - strstr (optarg, "%") && - sscanf (optarg, "%f,%d%%", &warn_size_bytes, &warn_percent) == 2) { - warn_size_bytes = floorf(warn_size_bytes); - break; - } - else if (strstr (optarg, "%") && - sscanf (optarg, "%d%%", &warn_percent) == 1) { - break; - } - else { - usage4 (_("Warning threshold must be integer or percentage!")); - } - case 'c': /* critical size threshold */ - if (is_intnonneg (optarg)) { - crit_size_bytes = (float) atoi (optarg); - break; - } - else if (strstr (optarg, ",") && - strstr (optarg, "%") && - sscanf (optarg, "%f,%d%%", &crit_size_bytes, &crit_percent) == 2) { - crit_size_bytes = floorf(crit_size_bytes); - break; - } - else if (strstr (optarg, "%") && - sscanf (optarg, "%d%%", &crit_percent) == 1) { - break; - } - else { - usage4 (_("Critical threshold must be integer or percentage!")); + case 'w': /* warning size threshold */ + { + /* + * We expect either a positive integer value without a unit, which means + * the unit is Bytes or a positive integer value and a percentage sign (%), + * which means the value must be with 0 and 100 and is relative to the total swap + */ + size_t length; + length = strlen(optarg); + + if (optarg[length - 1] == '%') { + // It's percentage! + warn.is_percentage = true; + optarg[length - 1] = '\0'; + if (is_uint64(optarg, &warn.value)) { + if (warn.value > 100) { + usage4 (_("Warning threshold percentage must be <= 100!")); + } else { + break; + } + } + } else { + // It's Bytes + warn.is_percentage = false; + if (is_uint64(optarg, &warn.value)) { + break; + } else { + usage4 (_("Warning threshold be positive integer or percentage!")); + } + } } + case 'c': /* critical size threshold */ + { + /* + * We expect either a positive integer value without a unit, which means + * the unit is Bytes or a positive integer value and a percentage sign (%), + * which means the value must be with 0 and 100 and is relative to the total swap + */ + size_t length; + length = strlen(optarg); + + if (optarg[length - 1] == '%') { + // It's percentage! + crit.is_percentage = true; + optarg[length - 1] = '\0'; + if (is_uint64(optarg, &crit.value)) { + if (crit.value> 100) { + usage4 (_("Critical threshold percentage must be <= 100!")); + } else { + break; + } + } + } else { + crit.is_percentage = false; + if (is_uint64(optarg, &crit.value)) { + break; + } else { + usage4 (_("Critical threshold be positive integer or percentage!")); + } + } + } case 'a': /* all swap */ allswaps = TRUE; break; @@ -482,23 +540,6 @@ process_arguments (int argc, char **argv) c = optind; if (c == argc) return validate_arguments (); - if (warn_percent == 0 && is_intnonneg (argv[c])) - warn_percent = atoi (argv[c++]); - - if (c == argc) - return validate_arguments (); - if (crit_percent == 0 && is_intnonneg (argv[c])) - crit_percent = atoi (argv[c++]); - - if (c == argc) - return validate_arguments (); - if (warn_size_bytes == 0 && is_intnonneg (argv[c])) - warn_size_bytes = (float) atoi (argv[c++]); - - if (c == argc) - return validate_arguments (); - if (crit_size_bytes == 0 && is_intnonneg (argv[c])) - crit_size_bytes = (float) atoi (argv[c++]); return validate_arguments (); } @@ -508,17 +549,12 @@ process_arguments (int argc, char **argv) int validate_arguments (void) { - if (warn_percent == 0 && crit_percent == 0 && warn_size_bytes == 0 - && crit_size_bytes == 0) { + if (warn.value == 0 && crit.value == 0) { return ERROR; } - else if (warn_percent < crit_percent) { - usage4 - (_("Warning percentage should be more than critical percentage")); - } - else if (warn_size_bytes < crit_size_bytes) { + else if (warn.value < crit.value) { usage4 - (_("Warning free space should be more than critical free space")); + (_("Warning should be more than critical")); } return OK; } @@ -564,7 +600,6 @@ print_help (void) } - void print_usage (void) { -- cgit v1.2.3-74-g34f1