allow different source files, since processes might have their own network namespace

1 files changed, 8 insertions, 6 deletions

diff --git a/fsbm.c b/fsbm.c
index 18fa55c..80559ff 100644
--- a/fsbm.c
+++ b/fsbm.c
@@ -12,8 +12,6 @@
 #include <string.h>
 #include <stddef.h>
 
-#define PROC_NET_DEV "/proc/net/dev"
-
 struct iface {
 	char interface[IFNAMSIZ];
 	struct timeval timestamp;
@@ -27,6 +25,7 @@ bool request_name_enabled = false;
 volatile bool q = false;
 bool use_bits = false;
 char *request_name;
+char *netdev_path = "/proc/net/dev";
 
 struct iface *interfaces = NULL;
 size_t no_iface = 0;
@@ -71,9 +70,9 @@ void print_bps(double bytesPerSecond) {
 
 void print_stats() {
 	// Open /proc/net/dev
-	FILE *dev = fopen(PROC_NET_DEV, "r");
+	FILE *dev = fopen(netdev_path, "r");
 	if (!dev) {
-		fprintf(stderr, "cannot open %s - %s\n", PROC_NET_DEV, strerror(errno));
+		fprintf(stderr, "cannot open %s - %s\n", netdev_path, strerror(errno));
 		exit(EXIT_FAILURE);
 	}
 
@@ -174,7 +173,7 @@ int main(int argc, char **argv) {
 	int c; 
 	unsigned long long interval = 10 * 100000;
 
-	while ((c = getopt (argc, argv, "rbi:d:hv")) != -1) 
+	while ((c = getopt (argc, argv, "rbi:d:f:hv")) != -1) 
 		switch (c)
 		{
 			case 'b':
@@ -186,9 +185,12 @@ int main(int argc, char **argv) {
 				interval = interval * 100000;
 				break;
 			case 'h':
-				printf("USAGE: fsbm, -i shows only matching interface, -r gives raw counts, -b specifies bits, -d sets interval in 10ths of seconds, 1 sec default\n");
+				printf("USAGE: fsbm, \n\t-f use a different /net/dev file, like /proc/123/net/dev\n\t-i shows only matching interface, \n\t-r gives raw counts, \n\t-b specifies bits, \n\t-d sets interval in 10ths of seconds, 1 sec default\n");
 				exit(EXIT_SUCCESS);
 				break;
+			case 'f':
+				netdev_path = strdup(optarg);
+        break;
 			case 'i':
 				request_name_enabled = true;
 				request_name = strdup(optarg);