On Mon, Dec 01, 2014 at 02:07:03PM +, Damien Lespiau wrote:
> In the fallback code that looks for devices in /proc, the read() may
> return with -1 in case of error (interruption from a signal for
> instance). We'll then happily write '\0' to buf[-2].
>
> As we didn't really care about the signal interruption before, I kept it
> the same way, just making sure that retcode is > 0 to avoid that case.
>
> This was found by static analysis.
>
> Signed-off-by: Damien Lespiau
procfs support is dead, absolutely no point imo to fix it. From the
kernel:
commit cb6458f97b53d7f73043206c18014b3ca63ac345
Author: Daniel Vetter
Date: Thu Aug 8 15:41:34 2013 +0200
drm: remove procfs code, take 2
So almost two years ago I've tried to nuke the procfs code already
once before:
http://lists.freedesktop.org/archives/dri-devel/2011-October/015707.html
The conclusion was that userspace drivers (specifically libdrm device
node detection) stopped relying on procfs in 2001. But after some
digging it turned out that the drmstat tool in libdrm is still using
those files (but only when certain options are set). So we've decided
to keep profcs.
But I when I've started to dig around again what exactly this tool
does I've noticed that it tries to read the "mem", "vm", and "vma"
files from procfs. Now as far my git history digging shows "mem" never
did anything useful (at least in the version that first showed up in
upstream history in 2004) and the file was remove in
commit 955b12def42e83287c1bdb1411d99451753c1391
Author: Ben Gamari
Date: Tue Feb 17 20:08:49 2009 -0500
drm: Convert proc files to seq_file and introduce debugfs
Which means that for over 4 years drmstat has been broken, and no one
cared. In my opinion that's proof enough that no one is actually using
drmstat, and so that we can savely nuke the procfs support from drm.
While at it fix up the error case cleanup for debugfs in drm_get_minor.
v2: Fix dates, libdrm stopped relying on procfs for drm node detection
in 2001.
v3: fixup compilation warning for !CONFIG_DEBUG_FS, reported by
Fengguang Wu.
Cc: kbuild test robot
Cc: Dave Airlie
Signed-off-by: Daniel Vetter
Signed-off-by: Dave Airlie
Instead I think we should just rip this fallback code out. Volunteered?
You can reuse the digging I've done for the kernel side.
Cheers, Daniel
> ---
> xf86drm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/xf86drm.c b/xf86drm.c
> index d900b4b..106b8ab 100644
> --- a/xf86drm.c
> +++ b/xf86drm.c
> @@ -579,7 +579,7 @@ static int drmOpenByName(const char *name)
> if ((fd = open(proc_name, 0, 0)) >= 0) {
> retcode = read(fd, buf, sizeof(buf)-1);
> close(fd);
> - if (retcode) {
> + if (retcode > 0) {
> buf[retcode-1] = '\0';
> for (driver = pt = buf; *pt && *pt != ' '; ++pt)
> ;
> --
> 1.8.3.1
>
> ___
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> dri-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
