Commit 719524df authored by Daniel Vetter's avatar Daniel Vetter Committed by Dave Airlie

drm: hollow-out GET_CLIENT ioctl

We not only have debugfs files to do pretty much the equivalent of
lsof, we also have an ioctl. Not that compared to lsof this dumps a
wee bit more information, but we can still get at that from debugfs
easily.

I've dug around in mesa, libdrm and ddx histories and the only users
seem to be drm/tests/dristat.c and drm/tests/getclients.c. The later
is a testcase for the ioctl itself since up to

commit b018fcda
Author: Eric Anholt <eric@anholt.net>
Date:   Thu Nov 22 18:46:54 2007 +1000

    drm: Make DRM_IOCTL_GET_CLIENT return EINVAL when it can't find client #idx

there was actually no way at all for userspace to enumerate all
clients since the kernel just wouldn't tell it when to stop. Which
completely broke it's only user, dristat -c.

So obviously that ioctl wasn't much use for debugging. Hence I don't
see any point in keeping support for a tool which was pretty obviously
never really used, and while we have good replacements in the form of
equivalent debugfs files.

Still, to keep dristat -c from looping forever again stop it early by
returning an unconditional -EINVAL. Also add a comment in the code
about why.

v2: Slightly less hollowed-out implementation. libva uses GET_CLIENTS
to figure out whether the fd it has is already authenticated or not.
So we need to keep that part of things working. Simplest way is to
just return one entry to keep va_drm_is_authenticated in
libva/va/drm/va_drm_auth.c working.

This is exercised by igt/drm_get_client_auth which contains a
copypasta of the libva auth check code.

Cc: Gwenole Beauchesne <gwenole.beauchesne@intel.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarEric Anholt <eric@anholt.net>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent d678959f
...@@ -217,29 +217,30 @@ int drm_getclient(struct drm_device *dev, void *data, ...@@ -217,29 +217,30 @@ int drm_getclient(struct drm_device *dev, void *data,
struct drm_file *file_priv) struct drm_file *file_priv)
{ {
struct drm_client *client = data; struct drm_client *client = data;
struct drm_file *pt;
int idx;
int i;
idx = client->idx;
i = 0;
mutex_lock(&dev->struct_mutex); /*
list_for_each_entry(pt, &dev->filelist, lhead) { * Hollowed-out getclient ioctl to keep some dead old drm tests/tools
if (i++ >= idx) { * not breaking completely. Userspace tools stop enumerating one they
client->auth = pt->authenticated; * get -EINVAL, hence this is the return value we need to hand back for
client->pid = pid_vnr(pt->pid); * no clients tracked.
client->uid = from_kuid_munged(current_user_ns(), pt->uid); *
client->magic = pt->magic; * Unfortunately some clients (*cough* libva *cough*) use this in a fun
client->iocs = pt->ioctl_count; * attempt to figure out whether they're authenticated or not. Since
mutex_unlock(&dev->struct_mutex); * that's the only thing they care about, give it to the directly
* instead of walking one giant list.
*/
if (client->idx == 0) {
client->auth = file_priv->authenticated;
client->pid = pid_vnr(file_priv->pid);
client->uid = from_kuid_munged(current_user_ns(),
file_priv->uid);
client->magic = 0;
client->iocs = 0;
return 0; return 0;
} } else {
}
mutex_unlock(&dev->struct_mutex);
return -EINVAL; return -EINVAL;
}
} }
/** /**
......
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