Re: [libvirt] [PATCH] cgroup: preserve correct errno on failure
On 02/15/2011 07:33 PM, Eric Blake wrote:
On 02/15/2011 05:01 PM, Eric Blake wrote:
> * src/util/cgroup.c (virCgroupSetValueStr, virCgroupGetValueStr)
> (virCgroupRemoveRecursively): VIR_DEBUG can clobber errno.
> (virCgroupRemove): Use VIR_DEBUG rather than DEBUG.
> ---
> rc = virFileWriteStr(keypath, value, 0);
> if (rc< 0) {
> - DEBUG("Failed to write value '%s': %m", value);
> rc = -errno;
> + VIR_DEBUG("Failed to write value '%s': %m", value);
Should we go one step further and guarantee that VIR_DEBUG() does not
modify errno?
Yeah, that's just going a step further than what I did in commit
17e19add "Preserve errno across calls to error reporting functions &
VIR_FREE". Since there are cases when we want to report an error, but
not count it as an "error", that makes sense (also it makes a lot of
sense that instrumentation for debugging should be as non-intrusive as
possible).