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