[Qemu-devel] [PATCH v2] raw-posix: Detect CDROM via ioctl

[Cole Robinson <crobinso@redhat.com>]

Current CDROM detection is hardcoded based on source file name.
Make this smarter by attempting a CDROM specific ioctl.

This makes '-cdrom /dev/sr0' succeed with no media present.

v2: Give ioctl check higher priority than filename check

Signed-off-by: Cole Robinson <crobinso@redhat.com>
---
 block/raw-posix.c |   19 +++++++++++++++++--
 1 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 5a6a22b..b7254d8 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -1140,9 +1140,24 @@ static int cdrom_open(BlockDriverState *bs, const char *filename, int flags)
 
 static int cdrom_probe_device(const char *filename)
 {
+    int fd, ret, prio;
+
     if (strstart(filename, "/dev/cd", NULL))
-        return 100;
-    return 0;
+        prio = 50;
+
+    fd = open(filename, O_RDONLY | O_NONBLOCK);
+    if (fd < 0) {
+        goto out;
+    }
+
+    /* Attempt to detect via a CDROM specific ioctl */
+    ret = ioctl(fd, CDROM_DRIVE_STATUS, CDSL_CURRENT);
+    if (!(ret < 0 && errno == EINVAL))
+        prio = 100;
+
+    close(fd);
+out:
+    return prio;
 }
 
 static int cdrom_is_inserted(BlockDriverState *bs)
-- 
1.6.5.2