[PATCH] samples, bpf: Add duration option D for sampleip

[Kang Minchul <tegongkang@gmail.com>]

Although sampleip program can handle three options,
(-F for frequency, duration, and -h for help)
currently there is no independent option for duration.

This patch adds option -D for duration like below:

$ sudo ./samples/bpf/sampleip -h
USAGE: sampleip [-F freq] [-D duration]
       -F freq       # sample frequency (Hertz), default 99
       -D duration   # sampling duration (seconds), default 5

$ sudo ./samples/bpf/sampleip -F 120
Sampling at 120 Hertz for 5 seconds. Ctrl-C also ends.
ADDR                KSYM                          COUNT
...

$ sudo ./samples/bpf/sampleip -D 7
Sampling at 99 Hertz for 7 seconds. Ctrl-C also ends.
ADDR                KSYM                          COUNT
...

$ sudo ./samples/bpf/sampleip -F 120 -D 7
Sampling at 120 Hertz for 7 seconds. Ctrl-C also ends.
ADDR                KSYM                          COUNT
...

Signed-off-by: Kang Minchul <tegongkang@gmail.com>
---
 samples/bpf/sampleip_user.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/samples/bpf/sampleip_user.c b/samples/bpf/sampleip_user.c
index 921c505bb567..ce6aadd496e1 100644
--- a/samples/bpf/sampleip_user.c
+++ b/samples/bpf/sampleip_user.c
@@ -28,9 +28,9 @@ static int nr_cpus;
 
 static void usage(void)
 {
-	printf("USAGE: sampleip [-F freq] [duration]\n");
-	printf("       -F freq    # sample frequency (Hertz), default 99\n");
-	printf("       duration   # sampling duration (seconds), default 5\n");
+	printf("USAGE: sampleip [-F freq] [-D duration]\n");
+	printf("       -F freq       # sample frequency (Hertz), default 99\n");
+	printf("       -D duration   # sampling duration (seconds), default 5\n");
 }
 
 static int sampling_start(int freq, struct bpf_program *prog,
@@ -145,19 +145,20 @@ int main(int argc, char **argv)
 	char filename[256];
 
 	/* process arguments */
-	while ((opt = getopt(argc, argv, "F:h")) != -1) {
+	while ((opt = getopt(argc, argv, "F:D:h")) != -1) {
 		switch (opt) {
 		case 'F':
 			freq = atoi(optarg);
 			break;
+		case 'D':
+			secs = atoi(optarg);
+			break;
 		case 'h':
 		default:
 			usage();
 			return 0;
 		}
 	}
-	if (argc - optind == 1)
-		secs = atoi(argv[optind]);
 	if (freq == 0 || secs == 0) {
 		usage();
 		return 1;
-- 
2.34.1