From 719524df4a2e48fa7ca3ad1697fd9a7f85ec8ad3 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Thu, 8 Aug 2013 15:41:31 +0200 Subject: [PATCH] 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 b018fcdaa5e8b4eabb8cffda687d00004a3c4785 Author: Eric Anholt 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 Cc: David Herrmann Reviewed-by: David Herrmann Reviewed-by: Eric Anholt Signed-off-by: Daniel Vetter Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_ioctl.c | 43 +++++++++++++++++++------------------ 1 file changed, 22 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 0acf0807d1ad..ac8ca5ce0822 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -217,29 +217,30 @@ int drm_getclient(struct drm_device *dev, void *data, struct drm_file *file_priv) { 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) { - if (i++ >= idx) { - client->auth = pt->authenticated; - client->pid = pid_vnr(pt->pid); - client->uid = from_kuid_munged(current_user_ns(), pt->uid); - client->magic = pt->magic; - client->iocs = pt->ioctl_count; - mutex_unlock(&dev->struct_mutex); - - return 0; - } + /* + * Hollowed-out getclient ioctl to keep some dead old drm tests/tools + * not breaking completely. Userspace tools stop enumerating one they + * get -EINVAL, hence this is the return value we need to hand back for + * no clients tracked. + * + * Unfortunately some clients (*cough* libva *cough*) use this in a fun + * attempt to figure out whether they're authenticated or not. Since + * 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; + } else { + return -EINVAL; } - mutex_unlock(&dev->struct_mutex); - - return -EINVAL; } /** -- 2.20.1