diff options
| -rw-r--r-- | tools/lguest/lguest.c | 84 |
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; } |