Messages in this thread Patch in this message | | | Date | Mon, 7 Dec 2009 07:12:33 GMT | From | tip-bot for Ulrich Drepper <> | Subject | [tip:perf/urgent] perf tools: Optimize parse_subsystem_tracepoint_event() |
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Commit-ID: 180570fdb7a3c404b599f0a318c2ccf86e4827ed Gitweb: http://git.kernel.org/tip/180570fdb7a3c404b599f0a318c2ccf86e4827ed Author: Ulrich Drepper <drepper@redhat.com> AuthorDate: Sun, 6 Dec 2009 13:25:30 -0500 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Mon, 7 Dec 2009 08:09:29 +0100
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> --- tools/perf/util/parse-events.c | 15 +++------------ 1 files changed, 3 insertions(+), 12 deletions(-)
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 448a13b..e5bc0fb 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; }
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