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>
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@ -467,7 +467,6 @@ parse_subsystem_tracepoint_event(char *sys_name, char *flags)
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while ((evt_ent = readdir(evt_dir))) {
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char event_opt[MAX_EVOPT_LEN + 1];
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int len;
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unsigned int rem = MAX_EVOPT_LEN;
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if (!strcmp(evt_ent->d_name, ".")
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|| !strcmp(evt_ent->d_name, "..")
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@ -475,20 +474,12 @@ parse_subsystem_tracepoint_event(char *sys_name, char *flags)
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|| !strcmp(evt_ent->d_name, "filter"))
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continue;
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len = snprintf(event_opt, MAX_EVOPT_LEN, "%s:%s", sys_name,
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evt_ent->d_name);
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len = snprintf(event_opt, MAX_EVOPT_LEN, "%s:%s%s%s", sys_name,
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evt_ent->d_name, flags ? ":" : "",
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flags ?: "");
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if (len < 0)
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return EVT_FAILED;
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rem -= len;
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if (flags) {
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if (rem < strlen(flags) + 1)
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return EVT_FAILED;
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strcat(event_opt, ":");
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strcat(event_opt, flags);
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}
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if (parse_events(NULL, event_opt, 0))
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return EVT_FAILED;
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}
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