From: Parth Shah <parths1229@gmail.com>
Date: Wed, 31 Mar 2021 11:59:06 +0000 (+0530)
Subject: pidstat: Monitor and show stats at the end of the exec program
X-Git-Tag: v12.5.4~7^2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b1c503ba990615602d0b2d3b4ad9521b0c8219b2;p=sysstat

pidstat: Monitor and show stats at the end of the exec program

Do not set alarms for undefined value of the interval. Also allow to
print stats even if the SIGINT/SIGCHLD occurs before first interval.
Hence, the command `pidstat -e <prog-name>`
will monitor the prog-name process and show the PID stats after the
prog-name is completed its execution.

Signed-off-by: Parth Shah <parths1229@gmail.com>
---

diff --git a/pidstat.c b/pidstat.c
index 076e664..0f827f8 100644
--- a/pidstat.c
+++ b/pidstat.c
@@ -2366,15 +2366,14 @@ void rw_pidstat_loop(int dis_hdr, int rows)
 	if (!interval) {
 		/* Display since boot time */
 		ps_tstamp[1] = ps_tstamp[0];
-		write_stats(0, DISP_HDR);
-		exit(0);
 	}
 
 	/* Set a handler for SIGALRM */
 	memset(&alrm_act, 0, sizeof(alrm_act));
 	alrm_act.sa_handler = alarm_handler;
 	sigaction(SIGALRM, &alrm_act, NULL);
-	alarm(interval);
+	if (interval)
+		alarm(interval);
 
 	/* Save the first stats collected. Will be used to compute the average */
 	ps_tstamp[2] = ps_tstamp[0];
@@ -2392,7 +2391,7 @@ void rw_pidstat_loop(int dis_hdr, int rows)
 	/* Wait for SIGALRM (or possibly SIGINT) signal */
 	__pause();
 
-	if (signal_caught)
+	if (signal_caught && interval)
 		/* SIGINT/SIGCHLD signals caught during first interval: Exit immediately */
 		return;