mlouielu / header-struct-safety-test-data

Header/Struct Safety Test Data

Header/Struct Safety Test Data

Example Struct Layout

struct velocity {
  double x;
  double y;
  double z;
};

struct foobar {
  int32_t posx;
  int32_t posy;
  int32_t posz;

  struct velocity vel;

  struct timespec curr_time;
};

How to Use

• Build

$ make build
gcc -Wall gen_data.c -o gen_data

• Generate Data

$ make gen-data
./gen_data
$ ls
... test.bin ...

• Python Convert (by struct)

$ make py-convert
python decode_binary.py test.bin
(10, 20, 30, 0, 0.1, 0.5, 0.7, 143399, 356331540)
(30, 40, 50, 0, 0.1, 0.5, 0.7, 143399, 356335599)
(60, 70, 80, 0, 0.1, 0.5, 0.7, 143399, 356335703)

• pahole

$ make pahole
pahole -E -M -C foobar gen_data
struct foobar {
	/* typedef int32_t -> __int32_t */ int                        posx;              /*     0     4 */
	/* typedef int32_t -> __int32_t */ int                        posy;              /*     4     4 */
	/* typedef int32_t -> __int32_t */ int                        posz;              /*     8     4 */

	/* XXX 4 bytes hole, try to pack */

	struct velocity {
		double             x;                                                    /*    16     8 */
		double             y;                                                    /*    24     8 */
		double             z;                                                    /*    32     8 */
	} vel; /*    16    24 */
	struct timespec {
		/* typedef __time_t */ long int           tv_sec;                        /*    40     8 */
		/* typedef __syscall_slong_t */ long int           tv_nsec;              /*    48     8 */
	} curr_time; /*    40    16 */

	/* size: 56, cachelines: 1, members: 5 */
	/* sum members: 52, holes: 1, sum holes: 4 */
	/* last cacheline: 56 bytes */
};

• Clean (remove .bin and gen_data)

$ make clean
rm gen_data test.bin