[tip:perf/core] perf util: Improve error checking for time percent input

[tip-bot for Jin Yao]

Commit-ID:  6e761cbc9127fb8fc609aea2265ee8279b8d6c55
Gitweb:     https://git.kernel.org/tip/6e761cbc9127fb8fc609aea2265ee8279b8d6c55
Author:     Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 10 Jan 2018 23:00:28 +0800
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 17 Jan 2018 10:23:35 -0300

perf util: Improve error checking for time percent input

The command line like 'perf report --stdio --time 1abc%/1' could be
accepted by perf. It looks not very good.

This patch uses strtod() to replace original atof() and check the entire
string. Now for the same command line, it would return error message
"Invalid time string".

root@skl:/tmp# perf report --stdio --time 1abc%/1
Invalid time string

Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Reviewed-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1515596433-24653-4-git-send-email-yao.jin@xxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/time-utils.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/time-utils.c b/tools/perf/util/time-utils.c
index 3f7f18f..88510ab 100644
--- a/tools/perf/util/time-utils.c
+++ b/tools/perf/util/time-utils.c
@@ -116,7 +116,8 @@ int perf_time__parse_str(struct perf_time_interval *ptime, const char *ostr)
 
 static int parse_percent(double *pcnt, char *str)
 {
-	char *c;
+	char *c, *endptr;
+	double d;
 
 	c = strchr(str, '%');
 	if (c)
@@ -124,8 +125,11 @@ static int parse_percent(double *pcnt, char *str)
 	else
 		return -1;
 
-	*pcnt = atof(str) / 100.0;
+	d = strtod(str, &endptr);
+	if (endptr != str + strlen(str))
+		return -1;
 
+	*pcnt = d / 100.0;
 	return 0;
 }