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authorDimitris Aragiorgis <dimara@arrikto.com>2015-06-23 13:45:00 +0300
committerStefan Hajnoczi <stefanha@redhat.com>2015-06-23 15:08:52 +0100
commit3307ed7b3fac5ba99eb3b84904b0b7cdc3592a61 (patch)
treefb98300d62b250a8976a07a9384a6ba27402d2e0
parenta93a3982a6645463fa822131d38b17284edd5633 (diff)
raw-posix: Introduce hdev_is_sg()
Until now, an SG device was identified only by checking if its path started with "/dev/sg". Then, hdev_open() would set the bs->sg flag accordingly. The patch relies on the actual properties of the device instead of the specified file path. To this end, test for an SG device (e.g. /dev/sg0) by ensuring that all of the following holds: - The specified file name corresponds to a character device - The device supports the SG_GET_VERSION_NUM ioctl - The device supports the SG_GET_SCSI_ID ioctl Signed-off-by: Dimitris Aragiorgis <dimara@arrikto.com> Message-id: 1435056300-14924-6-git-send-email-dimara@arrikto.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r--block/raw-posix.c39
1 files changed, 28 insertions, 11 deletions
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 57a243ff9f..cbe6574bf4 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -59,6 +59,7 @@
#include <linux/fd.h>
#include <linux/fs.h>
#include <linux/hdreg.h>
+#include <scsi/sg.h>
#ifdef __s390__
#include <asm/dasd.h>
#endif
@@ -2086,15 +2087,38 @@ static void hdev_parse_filename(const char *filename, QDict *options,
qdict_put_obj(options, "filename", QOBJECT(qstring_from_str(filename)));
}
+static bool hdev_is_sg(BlockDriverState *bs)
+{
+
+#if defined(__linux__)
+
+ struct stat st;
+ struct sg_scsi_id scsiid;
+ int sg_version;
+
+ if (stat(bs->filename, &st) >= 0 && S_ISCHR(st.st_mode) &&
+ !bdrv_ioctl(bs, SG_GET_VERSION_NUM, &sg_version) &&
+ !bdrv_ioctl(bs, SG_GET_SCSI_ID, &scsiid)) {
+ DPRINTF("SG device found: type=%d, version=%d\n",
+ scsiid.scsi_type, sg_version);
+ return true;
+ }
+
+#endif
+
+ return false;
+}
+
static int hdev_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVRawState *s = bs->opaque;
Error *local_err = NULL;
int ret;
- const char *filename = qdict_get_str(options, "filename");
#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;
@@ -2123,16 +2147,6 @@ static int hdev_open(BlockDriverState *bs, QDict *options, int flags,
#endif
s->type = FTYPE_FILE;
-#if defined(__linux__)
- {
- char resolved_path[ MAXPATHLEN ], *temp;
-
- temp = realpath(filename, resolved_path);
- if (temp && strstart(temp, "/dev/sg", NULL)) {
- bs->sg = 1;
- }
- }
-#endif
ret = raw_open_common(bs, options, flags, 0, &local_err);
if (ret < 0) {
@@ -2142,6 +2156,9 @@ static int hdev_open(BlockDriverState *bs, QDict *options, int flags,
return ret;
}
+ /* Since this does ioctl the device must be already opened */
+ bs->sg = hdev_is_sg(bs);
+
if (flags & BDRV_O_RDWR) {
ret = check_hdev_writable(s);
if (ret < 0) {