On Thu, Jan 22, 2015 at 8:57 PM, Wang Nan <wangn...@huawei.com> wrote:
> On 2015/1/22 21:27, Jiri Olsa wrote:
>> On Thu, Jan 22, 2015 at 01:36:43PM +0800, Wang Nan wrote:
>>> (If Steven Rostedt accept the previous patch which introduce a priv
>>> field to 'struct format_field', we can use a relative simple method
>>> for name conversion. If not , perf must track name conversion by
>>> itself.)
>>>
>>> Some parameters of syscall tracepoints named as 'nr', 'event', etc.
>>> When dealing with them, perf convert to ctf meets some problem:
>>>
>>> 1. If a parameter with name 'nr', it will duplicate syscall's
>>> common field 'nr'. One such syscall is io_submit().
>>>
>>> 2. If a parameter with name 'event', it is denied to be inserted
>>> because 'event' is a babeltrace keywork. One such syscall is
>>> epoll_ctl.
>>>
>>> This patch appends '_dupl_X' suffix to avoid problem 1, prepend a '_'
>>> prefix to avoid problem 2.
>>
>> I've got compilation error:
>>
>> util/data-convert-bt.c: In function ‘event_class_add_field’:
>> util/data-convert-bt.c:629:2: error: suggest parentheses around assignment
>> used as truth value [-Werror=parentheses]
>> while (t = bt_ctf_event_class_get_field_by_name(event_class, name)) {
>>
>> what's your gcc version? mine's caught that..
>>
>
> I also curious why you got so many Werror problems I'm not ever seen,
> until I found a '-w' in my gcc options, which is introduced by your commit
>
> 47810c1d429bc690e1f5e9467697538921962171: perf data: Disable Werror convert
> object.
>
> I'll revert that commit in my tree.
>
>> [jolsa@krava perf]$ gcc --version
>> gcc (GCC) 4.8.3 20140911 (Red Hat 4.8.3-7)
>>
>> SNIP
>>
>>>
>>> +/* If dup < 0, add a prefix. Else, add _dupl_X suffix. */
>>> +static char *change_name(char *name, char *orig_name, int dup)
>>> +{
>>> + char *new_name = NULL;
>>> + size_t len;
>>> +
>>> + if (!name)
>>> + name = orig_name;
>>> +
>>> + if (dup >= 10)
>>> + goto out;
>>> +
>>> + if (dup < 0)
>>> + len = strlen(name) + sizeof("_");
>>> + else
>>> + len = strlen(orig_name) + sizeof("_dupl_X");
>>
>> if we allow for _dupl_10, should we use 'sizeof("_dupl_x")' ^^^ in here?
>>
>>> +
>>> + new_name = malloc(len);
>>> + if (!new_name)
>>> + goto out;
>>> +
>>> + if (dup < 0)
>>> + snprintf(new_name, len, "_%s", name);
>>> + else
>>> + snprintf(new_name, len, "%s_dupl_%d", orig_name, dup);
>>> +
>>> +out:
>>> + if (name != orig_name)
>>> + free(name);
>>> + return new_name;
>>
>> SNIP
>>
>>> +
>>> + name = field->name;
>>> + while (t = bt_ctf_event_class_get_field_by_name(event_class, name)) {
>>> + bt_ctf_field_type_put(t);
>>> + name = change_name(name, field->name, dup++);
>>> + if (!name) {
>>> + pr_err("Failed to create dup name for '%s'\n",
>>> field->name);
>>> + return -1;
>>> + }
>>> + }
>>> +
>>> + ret = bt_ctf_event_class_add_field(event_class, type, name);
>>> +
>>> + /* if failed, we may hit a keywork. try again with a '_' prefix */
>>> + if (ret) {
>>> + name = change_name(name, field->name, -1);
>>> + if (!name) {
>>> + pr_err("Failed to alloc name for '_%s'\n",
>>> field->name);
>>> + return -1;
>>> + }
>>> + ret = bt_ctf_event_class_add_field(event_class, type, name);
>>
>> so there's no other way on checking up with the blacklist right?
>>
>
> AFAIK there's no official method to check blacklist right now. Utilizing
> existing
> functions to check blacklist is possible. For example, we can create a clock
> using
> bt_ctf_clock_create() with the checked name and then free it. However, it is
> hacky
> and I think you won't like it.
The prospect of seeing that code has convinced me to introduce
int bt_ctf_validate_identifier(const char *identifier);
commit 654c1444b546fd79b209288b93ed4e87d9bb8a2b
Author: Jérémie Galarneau <jeremie.galarn...@efficios.com>
Date: Fri Jan 23 16:24:52 2015 -0500
Add utility function to validate CTF identifiers
Introduces bt_ctf_validate_identifier() which validates a given
identifier against the list of CTF reserved keywords.
This function may evolve to perform additional validity checks in
the future as the CTF specification moves forward.
Acked-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarn...@efficios.com>
Does that take care of the problem?
Jérémie
>
> I believe my solution should be acceptable before babeltrace export its
> validate_identifier() function to users. Jérémie Galarneau, do you have better
> idea on it?
>
> Thanks.
>
>> thanks,
>> jirka
>>
>
>
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--
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com
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