Re: [libvirt] main: fix some compilation issues on non-linux platforms
On 08/16/2011 01:35 PM, Eric Blake wrote:
On 08/16/2011 11:29 AM, Eric Blake wrote:
>> +++ b/src/util/virpidfile.c
>> @@ -213,6 +213,8 @@ int virPidFileReadPathIfAlive(const char *path,
>> #ifdef __linux__
>> if (virFileLinkPointsTo(procpath, binpath) == 0)
>> *pid = -1;
>> +#else
>> + (void)binpath;
>> #endif
>
> Here, I'd rather mark binpath as ATTRIBUTE_UNUSED than add the #else
> preprocessor conditional. That is, ATTRIBUTE_UNUSED means only that the
> variable might be unused, not that it can't be used (so used on linux,
> unused otherwise qualifies).
Food for a separate patch: I see no reason why virFileLinkPointsTo
won't work on cygwin. That is, the fact that we used #ifdef __linux__
is wrong, since cygwin also has a working /proc/pid/ file tree to
determine if an executable is still valid; we should instead be doing
#if PROCFS_AVAIL, along with some sort of configuration check that
accepts both linux and cygwin procfs (or at least whatever aspect of
procfs that we are relying on in this function).
I split this off and pushed the rest.
If procfs's are different, then maybe we should use #if
PROCFS_PID_EXE_LINK_AVAIL here.
What is needed in this case seems to be that /proc/<pid>/exe is a
symbolic link to the executable. This works in Linux and cygwin. Would
testing via
stat /proc/<pid>/exe | sed -n 's/.*\(symbolic link\).*/\1/p'
be a valid test for this that works on all targeted platforms?
Stefan