1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
/* this tests whether we can use a sysv shared memory segment
as needed for the sysv varient of FAST_SHARE_MODES */
#if defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/sem.h>
#define KEY 0x963796
#define SEMKEY 0x963797
#define SIZE (32*1024)
#ifndef HAVE_UNION_SEMUN
union semun {
int val;
struct semid_ds *buf;
unsigned short *array;
};
#endif
main()
{
int id, sem_id;
int *buf;
int count=7;
union semun su;
#ifdef LINUX
if (sizeof(struct shmid_ds) == 52) {
printf("WARNING: You probably have a broken set of glibc2 include files - disabling sysv shared memory\n");
exit(1);
}
#endif
sem_id = semget(SEMKEY, 1, IPC_CREAT|IPC_EXCL|0600);
if (sem_id == -1) exit(1);
su.val = 1;
semctl(sem_id, 0, IPC_RMID, su);
id = shmget(KEY, 0, 0);
if (id != -1) {
if (shmctl(id, IPC_RMID, 0) != 0) exit(1);
}
if (fork() == 0) {
/* uggh - need locking */
sleep(2);
/* get an existing area */
id = shmget(KEY, 0, 0);
if (id == -1) exit(1);
buf = (int *)shmat(id, 0, 0);
if (buf == (int *)-1) exit(1);
while (count-- && buf[6124] != 55732) sleep(1);
if (count <= 0) exit(1);
buf[1763] = 7268;
exit(0);
}
id = shmget(KEY, SIZE, IPC_CREAT | IPC_EXCL | 0600);
if (id == -1) exit(1);
buf = (int *)shmat(id, 0, 0);
if (buf == (int *)-1) exit(1);
buf[6124] = 55732;
while (count-- && buf[1763] != 7268) sleep(1);
shmctl(id, IPC_RMID, 0);
if (count <= 0) exit(1);
exit(0);
}
|
