From c2e5d024a380bae6ead301fb4f40787b372ec3e0 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Tue, 1 Oct 2013 17:53:43 +0200 Subject: [PATCH] logind: check whether first drmSetMaster succeeded The initial drmSetMaster may fail if there is an active master already. We must not assume that all existing clients comply to logind rules. We check for this during session-activation already but didn't during device setup. Fix this by checking the return code. As drmSetMaster has had horrible return codes in the past (0 for failure? EINVAL for denied access, ..) we need to be quite pedantic. To guarantee an open file-descriptor we need to close the device and reopen it without master if setting master failed first. --- src/login/logind-session-device.c | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) diff --git a/src/login/logind-session-device.c b/src/login/logind-session-device.c index 27afafa1a..546c53710 100644 --- a/src/login/logind-session-device.c +++ b/src/login/logind-session-device.c @@ -144,7 +144,7 @@ static int sd_drmdropmaster(int fd) { } static int session_device_open(SessionDevice *sd, bool active) { - int fd; + int fd, r; assert(sd->type != DEVICE_TYPE_UNKNOWN); @@ -155,9 +155,17 @@ static int session_device_open(SessionDevice *sd, bool active) { switch (sd->type) { case DEVICE_TYPE_DRM: - if (active) - sd_drmsetmaster(fd); - else { + if (active) { + /* Weird legacy DRM semantics might return an error + * even though we're master. No way to detect that so + * fail at all times and let caller retry in inactive + * state. */ + r = sd_drmsetmaster(fd); + if (r < 0) { + close(fd); + return r; + } + } else { /* DRM-Master is granted to the first user who opens a * device automatically (ughh, racy!). Hence, we just * drop DRM-Master in case we were the first. */ @@ -384,9 +392,17 @@ int session_device_new(Session *s, dev_t dev, SessionDevice **out) { * revoke access and thus invalidate the fd. But this is still needed * to pass a valid fd back. */ sd->active = session_is_active(s); - sd->fd = session_device_open(sd, sd->active); - if (sd->fd < 0) - goto error; + r = session_device_open(sd, sd->active); + if (r < 0) { + /* EINVAL _may_ mean a master is active; retry inactive */ + if (sd->active && r == -EINVAL) { + sd->active = false; + r = session_device_open(sd, false); + } + if (r < 0) + goto error; + } + sd->fd = r; LIST_PREPEND(SessionDevice, sd_by_device, sd->device->session_devices, sd); -- 2.30.2