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-rw-r--r--tools/lguest/lguest.c84
1 files changed, 35 insertions, 49 deletions
diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c
index fd2f9221b241..07a03452c227 100644
--- a/tools/lguest/lguest.c
+++ b/tools/lguest/lguest.c
@@ -179,29 +179,6 @@ static struct termios orig_term;
#define wmb() __asm__ __volatile__("" : : : "memory")
#define mb() __asm__ __volatile__("" : : : "memory")
-/*
- * Convert an iovec element to the given type.
- *
- * This is a fairly ugly trick: we need to know the size of the type and
- * alignment requirement to check the pointer is kosher. It's also nice to
- * have the name of the type in case we report failure.
- *
- * Typing those three things all the time is cumbersome and error prone, so we
- * have a macro which sets them all up and passes to the real function.
- */
-#define convert(iov, type) \
- ((type *)_convert((iov), sizeof(type), __alignof__(type), #type))
-
-static void *_convert(struct iovec *iov, size_t size, size_t align,
- const char *name)
-{
- if (iov->iov_len != size)
- errx(1, "Bad iovec size %zu for %s", iov->iov_len, name);
- if ((unsigned long)iov->iov_base % align != 0)
- errx(1, "Bad alignment %p for %s", iov->iov_base, name);
- return iov->iov_base;
-}
-
/* Wrapper for the last available index. Makes it easier to change. */
#define lg_last_avail(vq) ((vq)->last_avail_idx)
@@ -228,7 +205,8 @@ static bool iov_empty(const struct iovec iov[], unsigned int num_iov)
}
/* Take len bytes from the front of this iovec. */
-static void iov_consume(struct iovec iov[], unsigned num_iov, unsigned len)
+static void iov_consume(struct iovec iov[], unsigned num_iov,
+ void *dest, unsigned len)
{
unsigned int i;
@@ -236,11 +214,16 @@ static void iov_consume(struct iovec iov[], unsigned num_iov, unsigned len)
unsigned int used;
used = iov[i].iov_len < len ? iov[i].iov_len : len;
+ if (dest) {
+ memcpy(dest, iov[i].iov_base, used);
+ dest += used;
+ }
iov[i].iov_base += used;
iov[i].iov_len -= used;
len -= used;
}
- assert(len == 0);
+ if (len != 0)
+ errx(1, "iovec too short!");
}
/* The device virtqueue descriptors are followed by feature bitmasks. */
@@ -864,7 +847,7 @@ static void console_output(struct virtqueue *vq)
warn("Write to stdout gave %i (%d)", len, errno);
break;
}
- iov_consume(iov, out, len);
+ iov_consume(iov, out, NULL, len);
}
/*
@@ -1591,9 +1574,9 @@ static void blk_request(struct virtqueue *vq)
{
struct vblk_info *vblk = vq->dev->priv;
unsigned int head, out_num, in_num, wlen;
- int ret;
+ int ret, i;
u8 *in;
- struct virtio_blk_outhdr *out;
+ struct virtio_blk_outhdr out;
struct iovec iov[vq->vring.num];
off64_t off;
@@ -1603,32 +1586,36 @@ static void blk_request(struct virtqueue *vq)
*/
head = wait_for_vq_desc(vq, iov, &out_num, &in_num);
- /*
- * Every block request should contain at least one output buffer
- * (detailing the location on disk and the type of request) and one
- * input buffer (to hold the result).
- */
- if (out_num == 0 || in_num == 0)
- errx(1, "Bad virtblk cmd %u out=%u in=%u",
- head, out_num, in_num);
+ /* Copy the output header from the front of the iov (adjusts iov) */
+ iov_consume(iov, out_num, &out, sizeof(out));
+
+ /* Find and trim end of iov input array, for our status byte. */
+ in = NULL;
+ for (i = out_num + in_num - 1; i >= out_num; i--) {
+ if (iov[i].iov_len > 0) {
+ in = iov[i].iov_base + iov[i].iov_len - 1;
+ iov[i].iov_len--;
+ break;
+ }
+ }
+ if (!in)
+ errx(1, "Bad virtblk cmd with no room for status");
- out = convert(&iov[0], struct virtio_blk_outhdr);
- in = convert(&iov[out_num+in_num-1], u8);
/*
* For historical reasons, block operations are expressed in 512 byte
* "sectors".
*/
- off = out->sector * 512;
+ off = out.sector * 512;
/*
* In general the virtio block driver is allowed to try SCSI commands.
* It'd be nice if we supported eject, for example, but we don't.
*/
- if (out->type & VIRTIO_BLK_T_SCSI_CMD) {
+ if (out.type & VIRTIO_BLK_T_SCSI_CMD) {
fprintf(stderr, "Scsi commands unsupported\n");
*in = VIRTIO_BLK_S_UNSUPP;
wlen = sizeof(*in);
- } else if (out->type & VIRTIO_BLK_T_OUT) {
+ } else if (out.type & VIRTIO_BLK_T_OUT) {
/*
* Write
*
@@ -1636,10 +1623,10 @@ static void blk_request(struct virtqueue *vq)
* if they try to write past end.
*/
if (lseek64(vblk->fd, off, SEEK_SET) != off)
- err(1, "Bad seek to sector %llu", out->sector);
+ err(1, "Bad seek to sector %llu", out.sector);
- ret = writev(vblk->fd, iov+1, out_num-1);
- verbose("WRITE to sector %llu: %i\n", out->sector, ret);
+ ret = writev(vblk->fd, iov, out_num);
+ verbose("WRITE to sector %llu: %i\n", out.sector, ret);
/*
* Grr... Now we know how long the descriptor they sent was, we
@@ -1655,7 +1642,7 @@ static void blk_request(struct virtqueue *vq)
wlen = sizeof(*in);
*in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);
- } else if (out->type & VIRTIO_BLK_T_FLUSH) {
+ } else if (out.type & VIRTIO_BLK_T_FLUSH) {
/* Flush */
ret = fdatasync(vblk->fd);
verbose("FLUSH fdatasync: %i\n", ret);
@@ -1669,10 +1656,9 @@ static void blk_request(struct virtqueue *vq)
* if they try to read past end.
*/
if (lseek64(vblk->fd, off, SEEK_SET) != off)
- err(1, "Bad seek to sector %llu", out->sector);
+ err(1, "Bad seek to sector %llu", out.sector);
- ret = readv(vblk->fd, iov+1, in_num-1);
- verbose("READ from sector %llu: %i\n", out->sector, ret);
+ ret = readv(vblk->fd, iov + out_num, in_num);
if (ret >= 0) {
wlen = sizeof(*in) + ret;
*in = VIRTIO_BLK_S_OK;
@@ -1758,7 +1744,7 @@ static void rng_input(struct virtqueue *vq)
len = readv(rng_info->rfd, iov, in_num);
if (len <= 0)
err(1, "Read from /dev/random gave %i", len);
- iov_consume(iov, in_num, len);
+ iov_consume(iov, in_num, NULL, len);
totlen += len;
}