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logging: fix corrupted output 

Harald reported a problem in the logging:
http://lists.osmocom.org/pipermail/openbsc/2011-May/002896.html

Reverting 81e9636454 seems to
fix the problem. However, that workaround looks ugly.

Holger gives us another clue on what was wrong:
http://lists.osmocom.org/pipermail/openbsc/2011-May/002905.html

While digging in the manpage, I found this:

"The functions vprintf(), vfprintf(), vsprintf(), vsnprintf()
are equivalent to the functions printf(), fprintf(), sprintf(),
snprintf(), respectively, except that they are called with a
va_list instead of a variable number of arguments. These functions
do not call the va_end macro. Consequently, the value of ap is
undefined after the call. The application should call va_end(ap)
itself afterwards."
This commit is contained in:
Pablo Neira Ayuso 2011-05-19 01:40:43 +02:00 committed by Pablo Neira Ayuso
parent ba01fa44fe
commit dd93bf46ed
1 changed files with 6 additions and 0 deletions
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6
src/logging.c
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@ -198,6 +198,7 @@ static void _logp(unsigned int subsys, int level, char *file, int line,
llist_for_each_entry(tar, &osmo_log_target_list, entry) {
struct log_category *category;
int output = 0;
va_list bp;
category = &tar->categories[subsys];
/* subsystem is not supposed to be logged */
@ -224,7 +225,12 @@ static void _logp(unsigned int subsys, int level, char *file, int line,
if (!output)
continue;
/* According to the manpage, vsnprintf leaves the value of ap
* in undefined state. Since _output uses vsnprintf and it may
* be called several times, we have to pass a copy of ap. */
va_copy(bp, ap);
_output(tar, subsys, level, file, line, cont, format, ap);
va_end(bp);
}
}