vhost: check hugepage fstat error

Value returned from fstat is not checked for errors before being used.
This patch fixes following coverity issue.

    static uint64_t
    get_blk_size(int fd)
    {
    	struct stat stat;

    	fstat(fd, &stat);
    	return (uint64_t)stat.st_blksize;
    >>>  CID 107103 (#1 of 1): Unchecked return value from library
         (CHECKED_RETURN)
    >>>  check_return: Calling fstat(fd, &stat) without checking
         return value.
    >>>  This library function may fail and return an error code.

Fixes: 8f972312b8f4 ("vhost: support vhost-user")

Signed-off-by: Huawei Xie <huawei.xie@intel.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

diff --git a/lib/librte_vhost/vhost_user/virtio-net-user.c b/lib/librte_vhost/vhost_user/virtio-net-user.c
index a867a43..a6a48dc 100644 (file)
--- a/lib/librte_vhost/vhost_user/virtio-net-user.c
+++ b/lib/librte_vhost/vhost_user/virtio-net-user.c
@@ -63,9 +63,10 @@ static uint64_t
 get_blk_size(int fd)
 {
        struct stat stat;
+       int ret;
 
-       fstat(fd, &stat);
-       return (uint64_t)stat.st_blksize;
+       ret = fstat(fd, &stat);
+       return ret == -1 ? (uint64_t)-1 : (uint64_t)stat.st_blksize;
 }
 
 static void
@@ -167,6 +168,11 @@ user_set_mem_table(int vid, struct VhostUserMsg *pmsg)
                 * aligned.
                 */
                alignment = get_blk_size(pmsg->fds[idx]);
+               if (alignment == (uint64_t)-1) {
+                       RTE_LOG(ERR, VHOST_CONFIG,
+                               "couldn't get hugepage size through fstat\n");
+                       goto err_mmap;
+               }
                mapped_size = RTE_ALIGN_CEIL(mapped_size, alignment);
 
                mapped_address = (uint64_t)(uintptr_t)mmap(NULL,