[Qemu-devel] [PATCH] block/raw-posix.c: Make physical devices usable in QEMU under Mac OS X host

[Programmingkid]

Mac OS X can be picky when it comes to allowing the user
to use physical devices in QEMU. Most mounted volumes
appear to be off limits to QEMU. If an issue is detected,
a message is displayed showing the user how to unmount a
volume.

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

---
Changed cdromOK variable to cdrom_ok.
Set initial value of cdrom_ok to false.
Moved declaration of cdrom_ok variable to Mac OS X code block.
Replaced printf() calls with error_report().
Changed if (ret < 0) to if (ret != 0).

 block/raw-posix.c |  102 ++++++++++++++++++++++++++++++++++++++---------------
 1 files changed, 73 insertions(+), 29 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index aec9ec6..3625f35 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -42,9 +42,8 @@
 #include <IOKit/storage/IOMediaBSDClient.h>
 #include <IOKit/storage/IOMedia.h>
 #include <IOKit/storage/IOCDMedia.h>
-//#include <IOKit/storage/IOCDTypes.h>
 #include <CoreFoundation/CoreFoundation.h>
-#endif
+#endif /* (__APPLE__) && (__MACH__) */
 
 #ifdef __sun__
 #define _POSIX_PTHREAD_SEMANTICS 1
@@ -1975,9 +1974,9 @@ BlockDriver bdrv_file = {
 /* host device */
 
 #if defined(__APPLE__) && defined(__MACH__)
-static kern_return_t FindEjectableCDMedia( io_iterator_t *mediaIterator );
-static kern_return_t GetBSDPath( io_iterator_t mediaIterator, char *bsdPath, 
CFIndex maxPathSize );
-
+static kern_return_t FindEjectableCDMedia(io_iterator_t *mediaIterator);
+static kern_return_t GetBSDPath(io_iterator_t mediaIterator, char *bsdPath,
+                                CFIndex maxPathSize, int flags);
 kern_return_t FindEjectableCDMedia( io_iterator_t *mediaIterator )
 {
     kern_return_t       kernResult;
@@ -2004,7 +2003,8 @@ kern_return_t FindEjectableCDMedia( io_iterator_t 
*mediaIterator )
     return kernResult;
 }
 
-kern_return_t GetBSDPath( io_iterator_t mediaIterator, char *bsdPath, CFIndex 
maxPathSize )
+kern_return_t GetBSDPath(io_iterator_t mediaIterator, char *bsdPath,
+                         CFIndex maxPathSize, int flags)
 {
     io_object_t     nextMedia;
     kern_return_t   kernResult = KERN_FAILURE;
@@ -2017,7 +2017,9 @@ kern_return_t GetBSDPath( io_iterator_t mediaIterator, 
char *bsdPath, CFIndex ma
         if ( bsdPathAsCFString ) {
             size_t devPathLength;
             strcpy( bsdPath, _PATH_DEV );
-            strcat( bsdPath, "r" );
+            if (flags & BDRV_O_NOCACHE) {
+                strcat(bsdPath, "r");
+            }
             devPathLength = strlen( bsdPath );
             if ( CFStringGetCString( bsdPathAsCFString, bsdPath + 
devPathLength, maxPathSize - devPathLength, kCFStringEncodingASCII ) ) {
                 kernResult = KERN_SUCCESS;
@@ -2030,7 +2032,34 @@ kern_return_t GetBSDPath( io_iterator_t mediaIterator, 
char *bsdPath, CFIndex ma
     return kernResult;
 }
 
-#endif
+/* Sets up a real cdrom for use in QEMU */
+static bool setupCDROM(char *bsdPath)
+{
+    int index, numOfTestPartitions = 2, fd;
+    char testPartition[MAXPATHLEN];
+    bool partitionFound = false;
+
+    /* look for a working partition */
+    for (index = 0; index < numOfTestPartitions; index++) {
+        snprintf(testPartition, sizeof(testPartition), "%ss%d", bsdPath, 
index);
+        fd = qemu_open(testPartition, O_RDONLY | O_BINARY | O_LARGEFILE);
+        if (fd >= 0) {
+            partitionFound = true;
+            qemu_close(fd);
+            break;
+        }
+    }
+
+    /* if a working partition on the device was not found */
+    if (partitionFound == false) {
+        error_report("Error: Failed to find a working partition on disc!\n");
+    } else {
+        DPRINTF("Using %s as optical disc\n", testPartition);
+        pstrcpy(bsdPath, MAXPATHLEN, testPartition);
+    }
+    return partitionFound;
+}
+#endif /* defined(__APPLE__) && defined(__MACH__) */
 
 static int hdev_probe_device(const char *filename)
 {
@@ -2120,32 +2149,31 @@ static int hdev_open(BlockDriverState *bs, QDict 
*options, int flags,
     int ret;
 
 #if defined(__APPLE__) && defined(__MACH__)
+    bool cdrom_ok = false;
     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 ) );
-
-        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';
+    /* If using a physical device */
+    if (strstart(filename, "/dev/", NULL)) {
+        char bsdPath[MAXPATHLEN];
+
+        /* If the physical device is a cdrom */
+        if (strcmp(filename, "/dev/cdrom") == 0) {
+            io_iterator_t mediaIterator;
+            FindEjectableCDMedia(&mediaIterator);
+            GetBSDPath(mediaIterator, bsdPath, sizeof(bsdPath), flags);
+            if (bsdPath[0] == '\0') {
+                error_report("Error: failed to obtain bsd path for optical"
+                                                                   " 
drive!\n");
             } else {
-                qemu_close(fd);
+                cdrom_ok = setupCDROM(bsdPath);
+                filename = bsdPath;
+            }
+
+            if (mediaIterator) {
+                IOObjectRelease(mediaIterator);
             }
-            filename = bsdPath;
             qdict_put(options, "filename", qstring_from_str(filename));
         }
-
-        if ( mediaIterator )
-            IOObjectRelease( mediaIterator );
     }
 #endif
 
@@ -2156,7 +2184,23 @@ static int hdev_open(BlockDriverState *bs, QDict 
*options, int flags,
         if (local_err) {
             error_propagate(errp, local_err);
         }
-        return ret;
+    }
+
+#if defined(__APPLE__) && defined(__MACH__)
+    /* if a physical device experienced an error while being opened */
+    if (strncmp(filename, "/dev/", 5) == 0 && (cdrom_ok == false || ret != 0)) 
{
+        error_report("Error: If device %s is mounted on the desktop, unmount"
+                              " it first before using it in QEMU.\n", 
filename);
+        error_report("Command to unmount device: diskutil unmountDisk %s\n",
+                                                                      
filename);
+        error_report("Command to mount device: diskutil mountDisk %s\n",
+                                                                      
filename);
+    }
+#endif /* defined(__APPLE__) && defined(__MACH__) */
+
+    /* End execution of this function if an error took place */
+    if (ret != 0) {
+       return ret;
     }
 
     /* Since this does ioctl the device must be already opened */
-- 
1.7.5.4