Re: [PATCH] tools: perf: util: parse-events.c: Cleaning up missing null-terminate after strncpy call

From: Rickard Strandqvist
Date: Wed Jun 04 2014 - 18:24:00 EST


Hi

A little embarrassing, but I actually did not know that there was a
better replacement for strncpy.

Sorry, but I will send a new platch based on strlcpy instead then,
snprintf i slow and unnecessary in this case.

Best regards
Rickard Strandqvist


2014-06-05 0:20 GMT+02:00 Andi Kleen <ak@xxxxxxxxxxxxxxx>:
> On Wed, Jun 04, 2014 at 11:46:18PM +0200, Rickard Strandqvist wrote:
>> Added a guaranteed null-terminate after call to strncpy.
>>
>> This was partly found using a static code analysis program called cppcheck.
>
> Should just stop using strncpy. strncpy semantics don't make any
> sense at all, and it's inefficient. I would just snprintf here
>
> -Andi
>
>>
>> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@xxxxxxxxxxxxxxxxxx>
>> ---
>> tools/perf/util/parse-events.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
>> index 1e15df1..fad2976 100644
>> --- a/tools/perf/util/parse-events.c
>> +++ b/tools/perf/util/parse-events.c
>> @@ -1216,8 +1216,10 @@ static void print_symbol_events(const char *event_glob, unsigned type,
>>
>> if (strlen(syms->alias))
>> snprintf(name, MAX_NAME_LEN, "%s OR %s", syms->symbol, syms->alias);
>> - else
>> + else {
>> strncpy(name, syms->symbol, MAX_NAME_LEN);
>> + name[sizeof(name) - 1] = '\0';
>> + }
>>
>> printf(" %-50s [%s]\n", name, event_type_descriptors[type]);
>>
>> --
>> 1.7.10.4
>>
>
> --
> ak@xxxxxxxxxxxxxxx -- Speaking for myself only
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