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.
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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