From 4ea19ecf322c2f98ef87fc980b3851625b082ac2 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Mon, 23 Mar 2020 19:25:06 -0500 Subject: ti_wilink_st.h: Replace zero-length array with flexible-array member The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva --- include/linux/ti_wilink_st.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/ti_wilink_st.h b/include/linux/ti_wilink_st.h index eb6cbdf10e50..44a7f9169ac6 100644 --- a/include/linux/ti_wilink_st.h +++ b/include/linux/ti_wilink_st.h @@ -295,7 +295,7 @@ struct bts_header { u32 magic; u32 version; u8 future[24]; - u8 actions[0]; + u8 actions[]; } __attribute__ ((packed)); /** @@ -305,7 +305,7 @@ struct bts_header { struct bts_action { u16 type; u16 size; - u8 data[0]; + u8 data[]; } __attribute__ ((packed)); struct bts_action_send { @@ -315,7 +315,7 @@ struct bts_action_send { struct bts_action_wait { u32 msec; u32 size; - u8 data[0]; + u8 data[]; } __attribute__ ((packed)); struct bts_action_delay { -- cgit v1.2.3-59-g8ed1b