Re: [Qemu-block] [PATCH v2] raw-posix.c: remove raw device access for cdrom

[Programmingkid]

Allows QEMU running on Mac OS X guest to use the real

CD-ROM drive.

This patch doesn't actually remove raw device access. I'm just

using the same name as the last patch.

Why should we test for /dev/disk1s0 when /dev/rdisk1s0 works?

By avoiding using the raw device we gain speed. When a read

takes place for the raw CD-ROM device, it has to start spinning

up if it went to sleep. This takes time to do. Plus there is 

that annoying spin up sound. With the non-raw access, QEMU

can use the operating system's buffers to do its reading. 

This means faster and quieter access. 

I have noticed that in order to use /dev/disk1s0, the CD-ROM

had to be unmounted (but not ejected) from the desktop. 

Disk Utility is what I used to accomplish this. 

Signed-off-by: John Arbuckle <address@hidden>

---

Tries more permutations of the CD-ROM device file.

Sets the needs_alignment variable.

Removes the unused kernResult variable.

 block/raw-posix.c |   62 ++++++++++++++++++++++++++++++++++++++++++++--------

 1 files changed, 52 insertions(+), 10 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c

index cbe6574..2088c1f 100644

--- a/block/raw-posix.c

+++ b/block/raw-posix.c

@@ -484,6 +484,19 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,

 

     filename = qemu_opt_get(opts, "filename");

 

+#ifdef __APPLE__

+

+    /*

+     * Raw CD-ROM access on a Macintosh needs to be aligned

+     * or reads will fail.

+     */

+

+    if (strncmp(filename, "/dev/r", 6) == 0) {

+        s->needs_alignment = true;

+    }

+

+#endif  /* __APPLE__ */

+

     ret = raw_normalize_devicepath(&filename);

     if (ret != 0) {

         error_setg_errno(errp, -ret, "Could not normalize device path");

@@ -2014,7 +2027,6 @@ kern_return_t GetBSDPath( io_iterator_t mediaIterator, char *bsdPath, CFIndex ma

         if ( bsdPathAsCFString ) {

             size_t devPathLength;

             strcpy( bsdPath, _PATH_DEV );

-            strcat( bsdPath, "r" );

             devPathLength = strlen( bsdPath );

             if ( CFStringGetCString( bsdPathAsCFString, bsdPath + devPathLength, maxPathSize - devPathLength, kCFStringEncodingASCII ) ) {

                 kernResult = KERN_SUCCESS;

@@ -2120,25 +2132,55 @@ static int hdev_open(BlockDriverState *bs, QDict *options, int flags,

     const char *filename = qdict_get_str(options, "filename");

 

     if (strstart(filename, "/dev/cdrom", NULL)) {

-        kern_return_t kernResult;

         io_iterator_t mediaIterator;

         char bsdPath[ MAXPATHLEN ];

         int fd;

 

-        kernResult = FindEjectableCDMedia( &mediaIterator );

-        kernResult = GetBSDPath( mediaIterator, bsdPath, sizeof( bsdPath ) );

+        FindEjectableCDMedia(&mediaIterator);

+        GetBSDPath(mediaIterator, bsdPath, sizeof(bsdPath));

 

         if ( bsdPath[ 0 ] != '\0' ) {

-            strcat(bsdPath,"s0");

-            /* some CDs don't have a partition 0 */

-            fd = qemu_open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE);

-            if (fd < 0) {

-                bsdPath[strlen(bsdPath)-1] = '1';

-            } else {

+            int devStringLength = strlen("/dev/");

+            char baseDeviceName[MAXPATHLEN];

+            int numberOfOptions = 4;

+            char deviceNameArray[numberOfOptions][MAXPATHLEN];

+            int i = 0;

+

+            /* remove the "/dev/" part from the device file's name */

+            strcpy(baseDeviceName, bsdPath + devStringLength);

+

+            /* /dev/disk*s0 */

+            sprintf(deviceNameArray[i++], "/dev/%ss0", baseDeviceName);

+

+            /* /dev/disk*s1 */

+            sprintf(deviceNameArray[i++], "/dev/%ss1", baseDeviceName);

+

+            /* /dev/rdisk*s0 */

+            sprintf(deviceNameArray[i++], "/dev/r%ss0", baseDeviceName);

+

+            /* /dev/rdisk*s1 */

+            sprintf(deviceNameArray[i++], "/dev/r%ss1", baseDeviceName);

+

+            /* Try device file permutions until one works */

+            for (i = 0; i < numberOfOptions; i++) {

+                fd = qemu_open(deviceNameArray[i], O_RDONLY | O_BINARY

+                                                            | O_LARGEFILE);

+                if (fd < 0) {

+                    DPRINTF("Error opening %s: %s\n", deviceNameArray[i]

+                                                    , strerror(errno));

+                } else {

+                    strcpy(bsdPath, (char *)deviceNameArray[i]);

+                    break;

+                }

+            }

+

+            if (fd > 0) {

                 qemu_close(fd);

             }

+

             filename = bsdPath;

             qdict_put(options, "filename", qstring_from_str(filename));

+            DPRINTF("cdrom is using %s\n", filename);

         }

 

         if ( mediaIterator )

-- 

1.7.5.4