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authorPhilippe Mathieu-Daudé <philmd@redhat.com>2019-01-03 09:56:35 +0100
committerMichael S. Tsirkin <mst@redhat.com>2019-01-17 21:10:57 -0500
commit97b583f46c435aaa40942ca73739d79190776b7f (patch)
tree53208b33ccfb6adb97554e33fe5acc7ba55591c2
parent1daff2f8193496b0e5e0ab56dc48c570c81f804e (diff)
block/sheepdog: Use QEMU_NONSTRING for non NUL-terminated arrays
GCC 8 added a -Wstringop-truncation warning: The -Wstringop-truncation warning added in GCC 8.0 via r254630 for bug 81117 is specifically intended to highlight likely unintended uses of the strncpy function that truncate the terminating NUL character from the source string. This new warning leads to compilation failures: CC block/sheepdog.o qemu/block/sheepdog.c: In function 'find_vdi_name': qemu/block/sheepdog.c:1239:5: error: 'strncpy' specified bound 256 equals destination size [-Werror=stringop-truncation] strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ make: *** [qemu/rules.mak:69: block/sheepdog.o] Error 1 As described previous to the strncpy() calls, the use of strncpy() is correct here: /* This pair of strncpy calls ensures that the buffer is zero-filled, * which is desirable since we'll soon be sending those bytes, and * don't want the send_req to read uninitialized data. */ strncpy(buf, filename, SD_MAX_VDI_LEN); strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); Use the QEMU_NONSTRING attribute, since this array is intended to store character arrays that do not necessarily contain a terminating NUL. Suggested-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
-rw-r--r--block/sheepdog.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/block/sheepdog.c b/block/sheepdog.c
index 90ab43baa4..ed14f7afbe 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -1224,7 +1224,7 @@ static int find_vdi_name(BDRVSheepdogState *s, const char *filename,
SheepdogVdiReq hdr;
SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
unsigned int wlen, rlen = 0;
- char buf[SD_MAX_VDI_LEN + SD_MAX_VDI_TAG_LEN];
+ char buf[SD_MAX_VDI_LEN + SD_MAX_VDI_TAG_LEN] QEMU_NONSTRING;
fd = connect_to_sdog(s, errp);
if (fd < 0) {