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")

Gustavo A. R. Silva committed 6 years ago

Commit 4ea19ec1 parent 16c33801 file · +3 −3Browse files

Showing the changes to include/linux (1 of 1 file). Show all

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include/linux/ti_wilink_st.h+3−3

@@ -295,7 +295,7 @@ struct bts_header { · 294 unmodified lines
295	u32 magic;	295	u32 magic;
296	u32 version;	296	u32 version;
297	u8 future[24];	297	u8 future[24];
298	u8 actions[0];	298	u8 actions[];
299	} __attribute__ ((packed));	299	} __attribute__ ((packed));
300		300
301	/**	301	/**
@@ -305,7 +305,7 @@ struct bts_header { · 3 unmodified lines
305	struct bts_action {	305	struct bts_action {
306	u16 type;	306	u16 type;
307	u16 size;	307	u16 size;
308	u8 data[0];	308	u8 data[];
309	} __attribute__ ((packed));	309	} __attribute__ ((packed));
310		310
311	struct bts_action_send {	311	struct bts_action_send {
@@ -315,7 +315,7 @@ struct bts_action_send { · 3 unmodified lines
315	struct bts_action_wait {	315	struct bts_action_wait {
316	u32 msec;	316	u32 msec;
317	u32 size;	317	u32 size;
318	u8 data[0];	318	u8 data[];
319	} __attribute__ ((packed));	319	} __attribute__ ((packed));
320		320
321	struct bts_action_delay {	321	struct bts_action_delay {