perf pmu: Factor out scale conversion code

Move the scale factor parsing code to an own function to reuse it in an
upcoming patch.

v2: Return error in case strdup returns NULL.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20170103150833.6694-2-andi@firstfloor.org
[ Keep returning -ENOMEM when strdup() fails in perf_pmu__parse_scale()/convert_scale() ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/pmu.c

@@ -94,32 +94,10 @@ static int pmu_format(const char *name, struct list_head *format)
 	return 0;
 }
 
-static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, char *dir, char *name)
+static int convert_scale(const char *scale, char **end, double *sval)
 {
-	struct stat st;
-	ssize_t sret;
-	char scale[128];
-	int fd, ret = -1;
-	char path[PATH_MAX];
 	char *lc;
-
-	snprintf(path, PATH_MAX, "%s/%s.scale", dir, name);
-
-	fd = open(path, O_RDONLY);
-	if (fd == -1)
-		return -1;
-
-	if (fstat(fd, &st) < 0)
-		goto error;
-
-	sret = read(fd, scale, sizeof(scale)-1);
-	if (sret < 0)
-		goto error;
-
-	if (scale[sret - 1] == '\n')
-		scale[sret - 1] = '\0';
-	else
-		scale[sret] = '\0';
+	int ret = 0;
 
 	/*
 	 * save current locale
@@ -134,7 +112,7 @@ static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, char *dir, char *
 	lc = strdup(lc);
 	if (!lc) {
 		ret = -ENOMEM;
-		goto error;
+		goto out;
 	}
 
 	/*
@@ -144,14 +122,42 @@ static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, char *dir, char *
 	 */
 	setlocale(LC_NUMERIC, "C");
 
-	alias->scale = strtod(scale, NULL);
+	*sval = strtod(scale, end);
 
+out:
 	/* restore locale */
 	setlocale(LC_NUMERIC, lc);
-
 	free(lc);
+	return ret;
+}
+
+static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, char *dir, char *name)
+{
+	struct stat st;
+	ssize_t sret;
+	char scale[128];
+	int fd, ret = -1;
+	char path[PATH_MAX];
+
+	snprintf(path, PATH_MAX, "%s/%s.scale", dir, name);
+
+	fd = open(path, O_RDONLY);
+	if (fd == -1)
+		return -1;
+
+	if (fstat(fd, &st) < 0)
+		goto error;
+
+	sret = read(fd, scale, sizeof(scale)-1);
+	if (sret < 0)
+		goto error;
+
+	if (scale[sret - 1] == '\n')
+		scale[sret - 1] = '\0';
+	else
+		scale[sret] = '\0';
 
-	ret = 0;
+	ret = convert_scale(scale, NULL, &alias->scale);
 error:
 	close(fd);
 	return ret;