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SubjectRe: [PATCH -next] tools build: Check return value of fwrite_unlocked in jvmti_agent.c
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在 2020/7/30 18:03, Arnaldo Carvalho de Melo 写道:
> Em Wed, Jul 29, 2020 at 04:47:36PM -0700, Ian Rogers escreveu:
>> On Fri, Jul 24, 2020 at 3:07 AM Wang ShaoBo <bobo.shaobowang@huawei.com> wrote:
>>> Function jvmti_write_code called by compiled_method_load_cb may return
>>> error in using fwrite_unlocked, this failure should be captured and
>>> warned.
>>>
>>> Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
>>> ---
>>> tools/perf/jvmti/jvmti_agent.c | 23 +++++++++++++++--------
>>> 1 file changed, 15 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/tools/perf/jvmti/jvmti_agent.c b/tools/perf/jvmti/jvmti_agent.c
>>> index 88108598d6e9..a1fe6aa16b6d 100644
>>> --- a/tools/perf/jvmti/jvmti_agent.c
>>> +++ b/tools/perf/jvmti/jvmti_agent.c
>>> @@ -363,7 +363,7 @@ jvmti_write_code(void *agent, char const *sym,
>>> struct jr_code_load rec;
>>> size_t sym_len;
>>> FILE *fp = agent;
>>> - int ret = -1;
>>> + int ret;
>>>
>>> /* don't care about 0 length function, no samples */
>>> if (size == 0)
>>> @@ -401,16 +401,23 @@ jvmti_write_code(void *agent, char const *sym,
>>> rec.code_index = code_generation++;
>>>
>>> ret = fwrite_unlocked(&rec, sizeof(rec), 1, fp);
>>> - fwrite_unlocked(sym, sym_len, 1, fp);
>>> + if (ret)
>>> + goto error;
>> Sorry, it seems I lost a reply to this. Won't ret here be the number
>> of items written and not an error code? Consequently all writes will
>> immediately goto error?
> Yeah, I removed it from tmp.perf/core.
>
> Wang, please address Ian review, and consider having just one out exit
> label.
>
> - Arnaldo
>

I am sorry I forgot what does fwrite_unlocked return, as same as fwrite
error happens,

the return val is a short item count (or zero)  but not equals the items
written. I have fixed

it and already sent v2 and address Ian review, thanks a lot.

... and i refer to the writing of function jvmti_write_debug_info() for
giving out exit label,

thanks again,

- Wang ShaoBo

>> Thanks,
>> Ian
>>
>>> + ret = fwrite_unlocked(sym, sym_len, 1, fp);
>>> + if (ret)
>>> + goto error;
>>>
>>> - if (code)
>>> - fwrite_unlocked(code, size, 1, fp);
>>> + if (code) {
>>> + ret = fwrite_unlocked(code, size, 1, fp);
>>> + if (ret)
>>> + goto error;
>>> + }
>>>
>>> funlockfile(fp);
>>> -
>>> - ret = 0;
>>> -
>>> - return ret;
>>> + return 0;
>>> +error:
>>> + funlockfile(fp);
>>> + return -1;
>>> }
>>>
>>> int
>>> --
>>> 2.17.1
>>>

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