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Re: [Qemu-devel] [PATCH] raw-posix.c: Make physical devices usable in QE
From: |
Laurent Vivier |
Subject: |
Re: [Qemu-devel] [PATCH] raw-posix.c: Make physical devices usable in QEMU |
Date: |
Thu, 09 Jul 2015 11:35:44 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 |
On 07/07/2015 19:33, Programmingkid wrote:
> Make physical devices like a USB flash drive or a CDROM drive work in
> QEMU. With
> this patch I can use a USB flash drive like a hard drive. Before this
> patch,
> QEMU would just quit with a message like "resource busy". Now it handles
> issues
> like these for the user. This patch unmounts volumes of physical devices
> before
> using them in QEMU. When QEMU quits, the physical devices are mounted again
> for the user. The user can find out which device files to use for their
> physical
> devices by running the mount command in the terminal. This patch makes
> "qemu-system-ppc -cdrom /dev/cdrom" work again on Mac OS X.
>
> Signed-off-by: John Arbuckle <address@hidden
> <mailto:address@hidden>>
Two comments:
- you should not mix several fixes in one patch (raw block device
management, partition seek, unmount/mount cdrom...)
- according to Stefan answer, I think you should not unmount the CDROM
but you should inform the user he must unmount it manually to be able to
use it.
Laurent
> ---
> block/raw-posix.c | 155
> ++++++++++++++++++++++++++++++++++++++++++++--------
> 1 files changed, 131 insertions(+), 24 deletions(-)
>
> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index cbe6574..af0981a 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -42,9 +42,10 @@
> #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
> +#include <sys/syslimits.h>
> +#include <fcntl.h>
> +#endif /* (__APPLE__) && (__MACH__) */
>
>
>
> #ifdef __sun__
> #define _POSIX_PTHREAD_SEMANTICS 1
> @@ -162,6 +163,25 @@ typedef struct BDRVRawState {
> bool needs_alignment;
> } BDRVRawState;
>
>
>
> +#ifdef __APPLE__
> +
> +#define MAX_NUM_DEVICES 7
> +
> +/*
> + * Keeps track of devices that need to be mounted
> + * when QEMU exists.
> + */
> +typedef struct {
> + int fd;
> + char filePath[MAXPATHLEN];
> +} PhysicalDevice;
> +
> +PhysicalDevice deviceArray[MAX_NUM_DEVICES];
> +int numberOfDevices;
> +
> +#endif /* __APPLE__ */
> +
> +
> typedef struct BDRVRawReopenState {
> int fd;
> int open_flags;
> @@ -1972,8 +1992,10 @@ 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);
> +void mountDevice(void);
>
>
>
> kern_return_t FindEjectableCDMedia( io_iterator_t *mediaIterator )
> {
> @@ -2001,7 +2023,8 @@ 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;
> @@ -2014,7 +2037,9 @@ 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;
> @@ -2027,7 +2052,54 @@ kern_return_t GetBSDPath( io_iterator_t
> mediaIterator, char *bsdPath, CFIndex ma
> return kernResult;
> }
>
>
>
> -#endif
> +/* Mounts unmounted devices onto host computer's desktop */
> +void mountDevice(void)
> +{
> + char commandBuffer[MAXPATHLEN];
> + int result, index;
> +
> + for (index = 0; index < numberOfDevices; index++) {
> + qemu_close(deviceArray[index].fd);
> + sprintf(commandBuffer, "diskutil mountDisk %s",
> +
> deviceArray[index].filePath);
> + DPRINTF("Issuing command: %s\n", commandBuffer);
> + result = system(commandBuffer);
> + if (result != 0) {
> + printf("Warning: problem detected while mounting %s\n",
> +
> deviceArray[index].filePath);
> + }
> + }
> +}
> +
> +/* Sets up a real cdrom for use in QEMU */
> +static void 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++) {
> + strcpy(testPartition, bsdPath);
> + sprintf(testPartition, "%ss%d", testPartition, 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 found */
> + if (partitionFound == false) {
> + printf("Error: Failed to find a working partition on CD!\n");
> + exit(EXIT_FAILURE);
> + }
> +
> + strcpy(bsdPath, testPartition);
> +}
> +
> +#endif /* defined(__APPLE__) && defined(__MACH__) */
>
>
>
> static int hdev_probe_device(const char *filename)
> {
> @@ -2119,30 +2191,52 @@ static int hdev_open(BlockDriverState *bs, QDict
> *options, int flags,
> #if defined(__APPLE__) && defined(__MACH__)
> const char *filename = qdict_get_str(options, "filename");
>
>
>
> - if (strstart(filename, "/dev/cdrom", NULL)) {
> - kern_return_t kernResult;
> - io_iterator_t mediaIterator;
> + /* If using a physical device */
> + if (strstart(filename, "/dev/", NULL)) {
> char bsdPath[ MAXPATHLEN ];
> - int fd;
>
>
>
> - kernResult = FindEjectableCDMedia( &mediaIterator );
> - kernResult = GetBSDPath( mediaIterator, bsdPath, sizeof(
> bsdPath ) );
> + /* 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 (mediaIterator) {
> + IOObjectRelease(mediaIterator);
> + }
> + }
>
>
>
> - 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 {
> - qemu_close(fd);
> + /* If the physical device is something else */
> + else {
> + strcpy(bsdPath, filename);
> + }
> +
> + /* if accessing a buffered device */
> + if ((flags & BDRV_O_NOCACHE) == 0) {
> + /*
> + * Unmount the device from the desktop before
> + * using the buffered device. A resource busy error
> + * would happen if we don't.
> + */
> + char commandBuffer[MAXPATHLEN];
> + int result;
> + sprintf(commandBuffer, "diskutil unmountDisk %s", bsdPath);
> + DPRINTF("Issuing command: %s\n", commandBuffer);
> + result = system(commandBuffer);
> + if (result != 0) {
> + printf("Warning: problem detected while unmounting %s\n",
> +
> bsdPath);
> }
> + }
> +
> + atexit(mountDevice);
> +
> + /* Setup a CDROM device if found */
> + if (bsdPath[0] != '\0' && (strcmp(filename, "/dev/cdrom") == 0)) {
> + setupCDROM(bsdPath);
> + DPRINTF("Using %s as CDROM\n", bsdPath);
> filename = bsdPath;
> qdict_put(options, "filename", qstring_from_str(filename));
> }
> -
> - if ( mediaIterator )
> - IOObjectRelease( mediaIterator );
> }
> #endif
>
>
>
> @@ -2156,6 +2250,19 @@ static int hdev_open(BlockDriverState *bs, QDict
> *options, int flags,
> return ret;
> }
>
>
>
> +#ifdef __APPLE__
> +
> + /* Add the fd to the fd array for mounting at exit */
> + if (strncmp(filename, "/dev/", 5) == 0) {
> + int mountFD = ((BDRVRawState *) bs->opaque)->fd;
> + DPRINTF("Queuing %s (fd: %d) for mounting at exit\n",
> + filename,
> mountFD);
> + deviceArray[numberOfDevices].fd = mountFD;
> + strcpy(deviceArray[numberOfDevices++].filePath, filename);
> + }
> +
> +#endif /* __APPLE__ */
> +
> /* Since this does ioctl the device must be already opened */
> bs->sg = hdev_is_sg(bs);
>
>
>
> --
> 1.7.5.4
>