From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
When disk is a cdrom and the drive is empty the "params" node in
xenstore might be missing completely: cope with it instead of
segfaulting.
Updated in v2:
- actually removed the strchr(blkdev->params, ':') that caused the
segfault;
- free all the allocated strings from xenstore before returning;
Updated in v3:
- set blkdev fields to NULL after free'ing them.
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
hw/xen_disk.c | 34 +++++++++++++++++++++++++++-------
1 files changed, 27 insertions(+), 7 deletions(-)
diff --git a/hw/xen_disk.c b/hw/xen_disk.c
index 096d1c9..faaa065 100644
--- a/hw/xen_disk.c
+++ b/hw/xen_disk.c
@@ -616,12 +616,14 @@ static int blk_init(struct XenDevice *xendev)
{
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
int index, qflags, have_barriers, info = 0;
- char *h;
/* read xenstore entries */
if (blkdev->params == NULL) {
+ char *h = NULL;
blkdev->params = xenstore_read_be_str(&blkdev->xendev, "params");
- h = strchr(blkdev->params, ':');
+ if (blkdev->params != NULL) {
+ h = strchr(blkdev->params, ':');
+ }
if (h != NULL) {
blkdev->fileproto = blkdev->params;
blkdev->filename = h+1;
@@ -649,7 +651,7 @@ static int blk_init(struct XenDevice *xendev)
blkdev->mode == NULL ||
blkdev->type == NULL ||
blkdev->dev == NULL) {
- return -1;
+ goto out_error;
}
/* read-only ? */
@@ -672,10 +674,15 @@ static int blk_init(struct XenDevice *xendev)
/* setup via xenbus -> create new block driver instance */
xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n");
blkdev->bs = bdrv_new(blkdev->dev);
- if (bdrv_open(blkdev->bs, blkdev->filename, qflags,
- bdrv_find_whitelisted_format(blkdev->fileproto)) != 0) {
- bdrv_delete(blkdev->bs);
- return -1;
+ if (blkdev->bs) {
+ if (bdrv_open(blkdev->bs, blkdev->filename, qflags,
+ bdrv_find_whitelisted_format(blkdev->fileproto)) != 0)
{
+ bdrv_delete(blkdev->bs);
+ blkdev->bs = NULL;
+ }
+ }
+ if (!blkdev->bs) {
+ goto out_error;
}
} else {
/* setup via qemu cmdline -> already setup for us */
@@ -704,6 +711,19 @@ static int blk_init(struct XenDevice *xendev)
xenstore_write_be_int(&blkdev->xendev, "sectors",
blkdev->file_size / blkdev->file_blk);
return 0;
+
+out_error:
+ qemu_free(blkdev->params);
+ blkdev->params = NULL;
+ qemu_free(blkdev->mode);
+ blkdev->mode = NULL;
+ qemu_free(blkdev->type);
+ blkdev->type = NULL;
+ qemu_free(blkdev->dev);
+ blkdev->dev = NULL;
+ qemu_free(blkdev->devtype);
+ blkdev->devtype = NULL;
+ return -1;
}
static int blk_connect(struct XenDevice *xendev)
--
1.7.2.3
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