From 361f29d46ce4a310818e88adaef0912573847295 Mon Sep 17 00:00:00 2001
From: Cole Robinson <crobinso@redhat.com>
Date: Thu, 14 Jan 2010 16:19:40 +0000
Subject: [PATCH] raw-posix: Detect CDROM via ioctl on linux

Current CDROM detection is hardcoded based on source file name.
Make this smarter on linux 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.

v3:
    Actually initialize 'prio' variable.
    Check for ioctl success rather than absence of specific failure.

v4:
    Explicitly mention that change is linux specific.

Signed-off-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
---
 block/raw-posix.c |   20 ++++++++++++++++++--
 1 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index c204cf9..1c777a1 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -1142,9 +1142,25 @@ static int cdrom_open(BlockDriverState *bs, const char *filename, int flags)

 static int cdrom_probe_device(const char *filename)
 {
+    int fd, ret;
+    int prio = 0;
+
     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)
+        prio = 100;
+
+    close(fd);
+out:
+    return prio;
 }

 static int cdrom_is_inserted(BlockDriverState *bs)
-- 
1.6.6.1