p/if1sec: initial add

plugins/system/1sec/if1sec-c.c

@@ -0,0 +1,273 @@
+/*
+ * if1sec C plugin
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <fcntl.h>
+
+#include <time.h>
+
+#include <sys/file.h>
+
+#define PROC_STAT "/proc/net/dev"
+#define PLUGIN_NAME "if1sec-c"
+
+int fail(char* msg) {
+	perror(msg);
+
+	return 1;
+}
+
+/* Returns the ifname from a /proc/net/dev line
+ * It will return an inside pointer to line, and modifiy the end with a \0
+ */
+char* get_ifname_from_procstatline(char* line) {
+	char *ifname;
+	for (ifname = line; (*ifname) == ' '; ifname ++);
+
+	char *ifname_end;
+	for (ifname_end = ifname; (*ifname_end) != ':'; ifname_end ++);
+	(*ifname_end) = '\0';
+
+	return ifname;
+}
+
+int config() {
+	/* Get the number of if */
+	int f;
+	if ( !(f=open(PROC_STAT, O_RDONLY)) ) {
+		return fail("cannot open " PROC_STAT);
+	}
+
+	// Starting with -2, since the 2 lines on top are header lines
+	int nif = -2;
+
+	const int buffer_size = 64 * 1024;
+	char buffer[buffer_size];
+
+	// whole /proc/stat can be read in 1 syscall
+	if (read(f, buffer, buffer_size) <= 0) {
+		return fail("cannot read " PROC_STAT);
+	}
+
+	// tokenization per-line
+	char* line; char *saveptr;
+	char* newl = "\n";
+	for (line = strtok_r(buffer, newl, &saveptr); line; line = strtok_r(NULL, newl, &saveptr)) {
+		// Skip the header lines
+		if (nif ++ < 0) { continue; }
+
+		char* if_name = get_ifname_from_procstatline(line);
+		printf(
+			"multigraph if_%s_1sec" "\n"
+			"graph_order down up" "\n"
+			"graph_title %s traffic" "\n"
+			"graph_category system::1sec" "\n"
+			"graph_vlabel bits in (-) / out (+) per ${graph_period}" "\n"
+			"graph_data_size custom 1d, 10s for 1w, 1m for 1t, 5m for 1y" "\n"
+			, if_name, if_name
+		);
+
+		printf(
+			"down.label -" "\n"
+			"down.type DERIVE" "\n"
+			"down.graph no" "\n"
+			"down.cdef down,8,*" "\n"
+			"down.min 0" "\n"
+					        
+			"up.label bps" "\n"
+			"up.type DERIVE" "\n"
+			"up.negative down" "\n"
+			"up.cdef down,8,*" "\n"
+			"up.min 0" "\n"
+		);
+	}
+
+	close(f);
+
+
+	return 0;
+}
+
+char* pid_filename;
+char* cache_filename;
+
+/* Wait until the next second, and return the EPOCH */
+time_t wait_until_next_second() {
+	struct timespec tp;
+	clock_gettime(CLOCK_REALTIME, &tp);
+
+	time_t current_epoch = tp.tv_sec;
+	long nsec_to_sleep = 1000*1000*1000 - tp.tv_nsec;
+
+
+	/* Only sleep if needed */
+	if (nsec_to_sleep > 0) {
+		tp.tv_sec = 0;
+		tp.tv_nsec = nsec_to_sleep;
+		nanosleep(&tp, NULL);
+	}
+
+	return current_epoch + 1;
+}
+
+int acquire() {
+
+	/* fork ourselves if not asked otherwise */
+	char* no_fork = getenv("no_fork");
+	if (! no_fork || strcmp("1", no_fork)) {
+		if (fork()) return;
+		// we are the child, complete the daemonization
+
+		/* Close standard IO */
+		fclose(stdin);
+		fclose(stdout);
+		fclose(stderr);
+
+		/* create new session and process group */
+		setsid();
+	}
+
+	/* write the pid */
+	FILE* pid_file = fopen(pid_filename, "w");
+	fprintf(pid_file, "%d\n", getpid());
+	fclose(pid_file);
+
+	/* Reading /proc/stat */
+	int f = open(PROC_STAT, O_RDONLY);
+
+	/* open the spoolfile */
+	int cache_file = open(cache_filename, O_CREAT | O_APPEND | O_WRONLY, S_IRUSR | S_IWUSR);
+
+	/* loop each second */
+	while (1) {
+		/* wait until next second */
+		time_t epoch = wait_until_next_second();
+
+		const int buffer_size = 64 * 1024;
+		char buffer[buffer_size];
+
+		if (lseek(f, 0, SEEK_SET) < 0) {
+			return fail("cannot seek " PROC_STAT);
+		}
+
+		// whole PROC file can be read in 1 syscall
+		if (read(f, buffer, buffer_size) <= 0) {
+			return fail("cannot read " PROC_STAT);
+		}
+
+		// ignore the 1rst line
+		char* line; char *saveptr;
+		const char* newl = "\n";
+
+		/* lock */
+		flock(cache_file, LOCK_EX);
+
+		int nif = -2;
+		for (line = strtok_r(buffer, newl, &saveptr); line; line = strtok_r(NULL, newl, &saveptr)) {
+			// Skip the header lines
+			if (nif ++ < 0) { continue; }
+
+			char if_id[64];
+			uint_fast64_t r_bytes, r_packets, r_errs, r_drop, r_fifo, r_frame, r_compressed, r_multicast;
+			uint_fast64_t t_bytes, t_packets, t_errs, t_drop, t_fifo, t_frame, t_compressed, t_multicast;
+			sscanf(line, "%s" 
+				" "
+				"%llu %llu %llu %llu %llu %llu %llu %llu" 
+				" " 
+				"%llu %llu %llu %llu %llu %llu %llu %llu"
+				, if_id
+				, &r_bytes, &r_packets, &r_errs, &r_drop, &r_fifo, &r_frame, &r_compressed, &r_multicast
+				, &t_bytes, &t_packets, &t_errs, &t_drop, &t_fifo, &t_frame, &t_compressed, &t_multicast
+			);
+
+			// Remove trailing ':' of if_id
+			if_id[strlen(if_id) - 1] = '\0';
+
+			char out_buffer[1024];
+			sprintf(out_buffer, 
+				"multigraph if_%s_1sec" "\n"
+				"up.value %ld:%llu" "\n"
+				"down.value %ld:%llu" "\n"
+				, if_id 
+				, epoch, r_bytes
+				, epoch, t_bytes
+			);
+
+			write(cache_file, out_buffer, strlen(out_buffer));
+		}
+
+		/* unlock */
+		flock(cache_file, LOCK_UN);
+	}
+
+	close(cache_file);
+	close(f);
+
+	return 0;
+}
+
+int fetch() {
+	FILE* cache_file = fopen(cache_filename, "r+");
+
+	/* lock */
+	flock(fileno(cache_file), LOCK_EX);
+
+	/* cat the cache_file to stdout */
+	char buffer[1024];
+	while (fgets(buffer, 1024, cache_file)) {
+		printf("%s", buffer);
+	}
+
+	ftruncate(fileno(cache_file), 0);
+	fclose(cache_file);
+
+	return 0;
+}
+
+int main(int argc, char **argv) {
+	/* resolve paths */
+	char *MUNIN_PLUGSTATE = getenv("MUNIN_PLUGSTATE");
+
+	/* Default is current directory */
+	if (! MUNIN_PLUGSTATE) MUNIN_PLUGSTATE = ".";
+
+	size_t MUNIN_PLUGSTATE_length = strlen(MUNIN_PLUGSTATE);
+
+	pid_filename = malloc(MUNIN_PLUGSTATE_length + strlen("/" PLUGIN_NAME ".") + strlen("pid") + 1); pid_filename[0] = '\0';
+	cache_filename = malloc(MUNIN_PLUGSTATE_length + strlen("/" PLUGIN_NAME ".") + strlen("value") + 1); cache_filename[0] = '\0';
+
+	strcat(pid_filename, MUNIN_PLUGSTATE);
+	strcat(pid_filename, "/" PLUGIN_NAME "." "pid");
+
+	strcat(cache_filename, MUNIN_PLUGSTATE);
+	strcat(cache_filename, "/" PLUGIN_NAME "." "value");
+
+	if (argc > 1) {
+		char* first_arg = argv[1];
+		if (! strcmp(first_arg, "config")) {
+			return config();
+		}
+
+		if (! strcmp(first_arg, "acquire")) {
+			return acquire();
+		}
+	}
+
+	return fetch();
+}
+
+/***** DEMO
+ 
+/proc/net/dev sample
+
+Inter-|   Receive                                                |  Transmit
+ face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
+    lo:    4364      54    0    0    0     0          0         0     4364      54    0    0    0     0       0          0
+  eth0: 3459461624 22016512    0   70    0     0          0         0 3670486138 18117144    0    0    0     0       0          0
+
+*****/