[1/2] qemu-io: Use correct range limitations

Commit Message

Max Reitz June 20, 2016, 2:26 p.m. UTC

create_iovec() has a comment lamenting the lack of SIZE_T_MAX. Since
there actually is a SIZE_MAX, use it.

Two places use INT_MAX for checking the upper bound of a sector count
that is used as an argument for a blk_*() function (blk_discard() and
blk_write_compressed(), respectively). BDRV_REQUEST_MAX_SECTORS should
be used instead.

And finally, do_co_pwrite_zeroes() used to similarly check that the
sector count does not exceed INT_MAX. However, this function is now
backed by blk_co_pwrite_zeroes() which takes bytes as an argument
instead of sectors. Therefore, it should be the byte count that does not
exceed INT_MAX, not the sector count.

Signed-off-by: Max Reitz <[e-mail]>
---
 qemu-io-cmds.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

Comments

Eric Blake June 20, 2016, 3:23 p.m. UTC | #1

On 06/20/2016 08:26 AM, Max Reitz wrote:
> create_iovec() has a comment lamenting the lack of SIZE_T_MAX. Since
> there actually is a SIZE_MAX, use it.
> 
> Two places use INT_MAX for checking the upper bound of a sector count
> that is used as an argument for a blk_*() function (blk_discard() and
> blk_write_compressed(), respectively). BDRV_REQUEST_MAX_SECTORS should
> be used instead.
> 
> And finally, do_co_pwrite_zeroes() used to similarly check that the
> sector count does not exceed INT_MAX. However, this function is now
> backed by blk_co_pwrite_zeroes() which takes bytes as an argument
> instead of sectors. Therefore, it should be the byte count that does not
> exceed INT_MAX, not the sector count.
> 
> Signed-off-by: Max Reitz <[e-mail]>
> ---
>  qemu-io-cmds.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 

> @@ -500,7 +499,7 @@ static int do_write_compressed(BlockBackend *blk, char *buf, int64_t offset,
>  {
>      int ret;
>  
> -    if (count >> 9 > INT_MAX) {
> +    if (count >> 9 > BDRV_REQUEST_MAX_SECTORS) {

Worth s/9/BDRV_SECTOR_BITS/ while touching it?  But not a show-stopper
either way.

Reviewed-by: Eric Blake <[e-mail]>

Patch

diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 09e879f..8237c2f 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -389,9 +389,8 @@  create_iovec(BlockBackend *blk, QEMUIOVector *qiov, char **argv, int nr_iov,
             goto fail;
         }
 
-        /* should be SIZE_T_MAX, but that doesn't exist */
-        if (len > INT_MAX) {
-            printf("Argument '%s' exceeds maximum size %d\n", arg, INT_MAX);
+        if (len > SIZE_MAX) {
+            printf("Argument '%s' exceeds maximum size %zu\n", arg, SIZE_MAX);
             goto fail;
         }
 
@@ -479,7 +478,7 @@  static int do_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
         .done   = false,
     };
 
-    if (count >> BDRV_SECTOR_BITS > INT_MAX) {
+    if (count > INT_MAX) {
         return -ERANGE;
     }
 
@@ -500,7 +499,7 @@  static int do_write_compressed(BlockBackend *blk, char *buf, int64_t offset,
 {
     int ret;
 
-    if (count >> 9 > INT_MAX) {
+    if (count >> 9 > BDRV_REQUEST_MAX_SECTORS) {
         return -ERANGE;
     }
 
@@ -1688,9 +1687,9 @@  static int discard_f(BlockBackend *blk, int argc, char **argv)
     if (count < 0) {
         print_cvtnum_err(count, argv[optind]);
         return 0;
-    } else if (count >> BDRV_SECTOR_BITS > INT_MAX) {
+    } else if (count >> BDRV_SECTOR_BITS > BDRV_REQUEST_MAX_SECTORS) {
         printf("length cannot exceed %"PRIu64", given %s\n",
-               (uint64_t)INT_MAX << BDRV_SECTOR_BITS,
+               (uint64_t)BDRV_REQUEST_MAX_SECTORS << BDRV_SECTOR_BITS,
                argv[optind]);
         return 0;
     }