libblkid: open device in nonblock mode.

When autoclose is set (kernel default but many distributions reverse the
setting) opening a CD-rom device causes the tray to close.

The function of blkid is to report the current state of the device and
not to change it. Hence it should use O_NONBLOCK when opening the
device to avoid closing a CD-rom tray.

blkid is used liberally in scripts so it can potentially interfere with
the user operating the CD-rom hardware.

[kzak@redhat.com: add O_NONBLOCK also to:
                  - wipefs
                  - blkid_new_probe_from_filename()
                  - blkid_evaluate_tag()]

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Karel Zak <kzak@redhat.com>
(cherry picked from commit 39f5af25982d8b0244000e92a9d0e0e6557d0e17)

diff --git a/src/udev/udev-builtin-blkid.c b/src/udev/udev-builtin-blkid.c
index 8798a5a5e298af0e21af08d4e117fca24130b4c3..1df41dab36bc34d9a21cbb491a9e5cd5cbd141f8 100644 (file)
--- a/src/udev/udev-builtin-blkid.c
+++ b/src/udev/udev-builtin-blkid.c
@@ -264,7 +264,7 @@ static int builtin_blkid(sd_device *dev, int argc, char *argv[], bool test) {
         if (r < 0)
                 return log_device_debug_errno(dev, r, "Failed to get device name: %m");
 
-        fd = open(devnode, O_RDONLY|O_CLOEXEC);
+        fd = open(devnode, O_RDONLY|O_CLOEXEC|O_NONBLOCK);
         if (fd < 0)
                 return log_device_debug_errno(dev, errno, "Failed to open block device %s: %m", devnode);