mpb: add threads.c plugin

tools/munin-plugins-busybox/Makefile

@@ -1,9 +1,10 @@
 CC=gcc
 CFLAGS=-W -Wall -pedantic -Wextra -g -O2
 OBJS=main.o common.o cpu.o entropy.o forks.o fw_packets.o interrupts.o \
-     if_err_.o load.o open_files.o open_inodes.o processes.o swap.o uptime.o
+     if_err_.o load.o open_files.o open_inodes.o processes.o swap.o threads.o \
+     uptime.o
 LINKS=cpu entropy forks fw_packets interrupts if_err_eth0 load open_files \
-      open_inodes processes swap uptime
+      open_inodes processes swap threads uptime
 
 %.o:%.c
 	${CC} ${CFLAGS} -c $< -o $@

tools/munin-plugins-busybox/main.c

@@ -14,6 +14,7 @@ int open_files(int argc, char **argv);
 int open_inodes(int argc, char **argv);
 int processes(int argc, char **argv);
 int swap(int argc, char **argv);
+int threads(int argc, char **argv);
 int uptime(int argc, char **argv);
 
 int busybox(int argc, char **argv) {
@@ -72,6 +73,10 @@ int main(int argc, char **argv) {
 			if(!strcmp(progname+1, "wap"))
 				return swap(argc, argv);
 			break;
+		case 't':
+			if(!strcmp(progname+1, "hreads"))
+				return threads(argc, argv);
+			break;
 		case 'u':
 			if(!strcmp(progname+1, "ptime"))
 				return uptime(argc, argv);

tools/munin-plugins-busybox/threads.c

@@ -0,0 +1,70 @@
+#include <ctype.h>
+#include <dirent.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include "common.h"
+
+int threads(int argc, char **argv) {
+	FILE *f;
+	char buff[256];
+	const char *s;
+	int i, sum;
+	DIR *d;
+	struct dirent *e;
+
+	if(argc > 1) {
+		if(!strcmp(argv[1], "autoconf")) {
+			i = getpid();
+			sprintf(buff, "/proc/%d/status", i);
+			if(NULL == (f = fopen(buff, "r")))
+				return fail("failed to open /proc/$$/status");
+			while(fgets(buff, 256, f))
+				if(!strncmp(buff, "Threads:", 8)) {
+					fclose(f);
+					return writeyes();
+				}
+			fclose(f);
+			puts("no");
+			return 0;
+		}
+		if(!strcmp(argv[1], "config")) {
+			puts("graph_title Number of threads\n"
+				"graph_vlabel number of threads\n"
+				"graph_category processes\n"
+				"graph_info This graph shows the number of threads.\n"
+				"threads.label threads\n"
+				"threads.info The current number of threads.");
+			return 0;
+		}
+	}
+	if(NULL == (d = opendir("/proc")))
+		return fail("cannot open /proc");
+	sum = 0;
+	while((e = readdir(d))) {
+		for(s=e->d_name;*s;++s)
+			if(!isdigit(*s))
+				break;
+		if(*s) /* non-digit found */
+			continue;
+		snprintf(buff, 256, "/proc/%s/status", e->d_name);
+		if(!(f = fopen(buff, "r")))
+			continue; /* process has vanished */
+		while(fgets(buff, 256, f)) {
+			if(strncmp(buff, "Threads:", 8))
+				continue;
+			if(1 != sscanf(buff+8, "%d", &i)) {
+				fclose(f);
+				closedir(d);
+				return fail("failed to parse "
+						"/proc/somepid/status");
+			}
+			sum += i;
+		}
+		fclose(f);
+	}
+	closedir(d);
+	printf("threads.value %d\n", sum);
+	return 0;
+}