linux-kernel - [PATCH v2 1/1] perf tools: remove sscanf extension %as

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Date:	Thu, 20 Sep 2012 23:37:50 +0300
From:	irina.tirdea@...il.com
To:	mingo@...hat.com, acme@...stprotocols.net, a.p.zijlstra@...llo.nl,
	rostedt@...dmis.org
Cc:	paulus@...ba.org, dsahern@...il.com, namhyung.kim@....com,
	linux-kernel@...r.kernel.org, masami.hiramatsu.pt@...achi.com,
	Irina Tirdea <irina.tirdea@...el.com>
Subject: [PATCH v2 1/1] perf tools: remove sscanf extension %as

From: Irina Tirdea <irina.tirdea@...el.com>

perf uses sscanf extension %as to read and allocate a
string in the same step. This is a non-standard extension
only present in new versions of glibc.

Replacing the use of sscanf and %as with strtok_r calls
in order to parse a given string into its components.
This is needed in Android since bionic does not support
%as extension for sscanf.

Signed-off-by: Irina Tirdea <irina.tirdea@...el.com>
---
 tools/perf/util/probe-event.c       |   36 ++++++++++++++++++++++++++++-------
 tools/perf/util/trace-event-parse.c |   18 ++++++++----------
 2 files changed, 37 insertions(+), 17 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 4ce04c2..49a256e 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1100,6 +1100,7 @@ static int parse_probe_trace_command(const char *cmd,
 	struct probe_trace_point *tp = &tev->point;
 	char pr;
 	char *p;
+	char *argv0_str = NULL, *fmt, *fmt1_str, *fmt2_str, *fmt3_str;
 	int ret, i, argc;
 	char **argv;
 
@@ -1116,14 +1117,27 @@ static int parse_probe_trace_command(const char *cmd,
 	}
 
 	/* Scan event and group name. */
-	ret = sscanf(argv[0], "%c:%a[^/ \t]/%a[^ \t]",
-		     &pr, (float *)(void *)&tev->group,
-		     (float *)(void *)&tev->event);
-	if (ret != 3) {
+	argv0_str = strdup(argv[0]);
+	if (argv0_str == NULL) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	fmt1_str = strtok_r(argv0_str, ":", &fmt);
+	fmt2_str = strtok_r(NULL, "/", &fmt);
+	fmt3_str = strtok_r(NULL, " \t", &fmt);
+	if (fmt1_str == NULL || strlen(fmt1_str) != 1 || fmt2_str == NULL
+	    || fmt3_str == NULL) {
 		semantic_error("Failed to parse event name: %s\n", argv[0]);
 		ret = -EINVAL;
 		goto out;
 	}
+	pr = fmt1_str[0];
+	tev->group = strdup(fmt2_str);
+	tev->event = strdup(fmt3_str);
+	if (tev->group == NULL || tev->event == NULL) {
+		ret = -ENOMEM;
+		goto out;
+	}
 	pr_debug("Group:%s Event:%s probe:%c\n", tev->group, tev->event, pr);
 
 	tp->retprobe = (pr == 'r');
@@ -1135,10 +1149,17 @@ static int parse_probe_trace_command(const char *cmd,
 		p++;
 	} else
 		p = argv[1];
-	ret = sscanf(p, "%a[^+]+%lu", (float *)(void *)&tp->symbol,
-		     &tp->offset);
-	if (ret == 1)
+	fmt1_str = strtok_r(p, "+", &fmt);
+	tp->symbol = strdup(fmt1_str);
+	if (tp->symbol == NULL) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	fmt2_str = strtok_r(NULL, "", &fmt);
+	if (fmt2_str == NULL)
 		tp->offset = 0;
+	else
+		tp->offset = strtoul(fmt2_str, NULL, 10);
 
 	tev->nargs = argc - 2;
 	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
@@ -1162,6 +1183,7 @@ static int parse_probe_trace_command(const char *cmd,
 	}
 	ret = 0;
 out:
+	free(argv0_str);
 	argv_free(argv);
 	return ret;
 }
diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
index aa4c860..3aabcd6 100644
--- a/tools/perf/util/trace-event-parse.c
+++ b/tools/perf/util/trace-event-parse.c
@@ -229,24 +229,22 @@ void parse_proc_kallsyms(struct pevent *pevent,
 	char *next = NULL;
 	char *addr_str;
 	char *mod;
-	char ch;
+	char *fmt;
 
 	line = strtok_r(file, "\n", &next);
 	while (line) {
 		mod = NULL;
-		sscanf(line, "%as %c %as\t[%as",
-		       (float *)(void *)&addr_str, /* workaround gcc warning */
-		       &ch, (float *)(void *)&func, (float *)(void *)&mod);
+		addr_str = strtok_r(line, " ", &fmt);
 		addr = strtoull(addr_str, NULL, 16);
-		free(addr_str);
-
-		/* truncate the extra ']' */
+		/* skip character */
+		strtok_r(NULL, " ", &fmt);
+		func = strtok_r(NULL, "\t", &fmt);
+		mod = strtok_r(NULL, "]", &fmt);
+		/* truncate the extra '[' */
 		if (mod)
-			mod[strlen(mod) - 1] = 0;
+			mod = mod + 1;
 
 		pevent_register_function(pevent, func, addr, mod);
-		free(func);
-		free(mod);
 
 		line = strtok_r(NULL, "\n", &next);
 	}
-- 
1.7.9.5

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