getopt: fix null pointer arithmetic ub
[musl] / src / ipc / shmctl.c
1 #include <sys/shm.h>
2 #include <endian.h>
3 #include "syscall.h"
4 #include "ipc.h"
5
6 #if __BYTE_ORDER != __BIG_ENDIAN
7 #undef SYSCALL_IPC_BROKEN_MODE
8 #endif
9
10 int shmctl(int id, int cmd, struct shmid_ds *buf)
11 {
12 #if IPC_TIME64
13         struct shmid_ds out, *orig;
14         if (cmd&IPC_TIME64) {
15                 out = (struct shmid_ds){0};
16                 orig = buf;
17                 buf = &out;
18         }
19 #endif
20 #ifdef SYSCALL_IPC_BROKEN_MODE
21         struct shmid_ds tmp;
22         if (cmd == IPC_SET) {
23                 tmp = *buf;
24                 tmp.shm_perm.mode *= 0x10000U;
25                 buf = &tmp;
26         }
27 #endif
28 #ifndef SYS_ipc
29         int r = __syscall(SYS_shmctl, id, IPC_CMD(cmd), buf);
30 #else
31         int r = __syscall(SYS_ipc, IPCOP_shmctl, id, IPC_CMD(cmd), 0, buf, 0);
32 #endif
33 #ifdef SYSCALL_IPC_BROKEN_MODE
34         if (r >= 0) switch (cmd | IPC_TIME64) {
35         case IPC_STAT:
36         case SHM_STAT:
37         case SHM_STAT_ANY:
38                 buf->shm_perm.mode >>= 16;
39         }
40 #endif
41 #if IPC_TIME64
42         if (r >= 0 && (cmd&IPC_TIME64)) {
43                 buf = orig;
44                 *buf = out;
45                 IPC_HILO(buf, shm_atime);
46                 IPC_HILO(buf, shm_dtime);
47                 IPC_HILO(buf, shm_ctime);
48         }
49 #endif
50         return __syscall_ret(r);
51 }