pidstat: Don't stop if gtime and cgtime fields are unavailable

With some old 2.6 kernels, fields "gtime" and "cgtime" (which are
expected to be read from /proc/#/stat file) may not be present.
pidstat used to stop should this case happens.
Fix this since these fields are not mandatory for pidstat to display its
statistics.

Signed-off-by: Sebastien GODARD <[email protected]>

Author: sysstat

pidstat.c

@@ -356,9 +356,14 @@ int read_proc_pid_stat(unsigned int pid, struct pid_stats *pst,
 		    &pst->priority, &pst->policy,
 		    &pst->blkio_swapin_delays, &pst->gtime, &pst->cgtime);
 
-	if (rc < 17)
+	if (rc < 15)
 		return 1;
 
+	if (rc < 17) {
+		/* gtime and cgtime fields are unavailable in file */
+		pst->gtime = pst->cgtime = 0;
+	}
+
 	/* Convert to kB */
 	pst->vsz >>= 10;
 	pst->rss = PG_TO_KB(pst->rss);