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authorUlrich Drepper <drepper@redhat.com>2009-12-06 13:25:30 -0500
committerIngo Molnar <mingo@elte.hu>2009-12-07 08:09:29 +0100
commit180570fdb7a3c404b599f0a318c2ccf86e4827ed (patch)
tree1251ef18261812270c2080dc72ba4a4229917a90
parent67a6259ec97b8408f86f2fe8459d2233f0b0987d (diff)
perf tools: Optimize parse_subsystem_tracepoint_event()
Uses of strcat are almost always signs that someone is too lazy to think about the code a bit more carefully. One always has to know about the lengths of the strings involved to avoid buffer overflows. This is one case where the size of the object code for me is reduced by 38 bytes. The code should also be faster, especially if flags is non-NULL. Signed-off-by: Ulrich Drepper <drepper@redhat.com> Cc: a.p.zijlstra@chello.nl Cc: fweisbec@gmail.com Cc: jaswinderrajput@gmail.com Cc: paulus@samba.org LKML-Reference: <200912061825.nB6IPUa1023306@hs20-bc2-1.build.redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--tools/perf/util/parse-events.c15
1 files changed, 3 insertions, 12 deletions
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 448a13b5201..e5bc0fb016b 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -467,7 +467,6 @@ parse_subsystem_tracepoint_event(char *sys_name, char *flags)
while ((evt_ent = readdir(evt_dir))) {
char event_opt[MAX_EVOPT_LEN + 1];
int len;
- unsigned int rem = MAX_EVOPT_LEN;
if (!strcmp(evt_ent->d_name, ".")
|| !strcmp(evt_ent->d_name, "..")
@@ -475,20 +474,12 @@ parse_subsystem_tracepoint_event(char *sys_name, char *flags)
|| !strcmp(evt_ent->d_name, "filter"))
continue;
- len = snprintf(event_opt, MAX_EVOPT_LEN, "%s:%s", sys_name,
- evt_ent->d_name);
+ len = snprintf(event_opt, MAX_EVOPT_LEN, "%s:%s%s%s", sys_name,
+ evt_ent->d_name, flags ? ":" : "",
+ flags ?: "");
if (len < 0)
return EVT_FAILED;
- rem -= len;
- if (flags) {
- if (rem < strlen(flags) + 1)
- return EVT_FAILED;
-
- strcat(event_opt, ":");
- strcat(event_opt, flags);
- }
-
if (parse_events(NULL, event_opt, 0))
return EVT_FAILED;
}