1 /* Check that Helgrind does not complain about semaphores with a
2 nonzero initial value, when said semaphores are correctly used.
3 Also useful for generating VCG of simple semaphore activity, for
4 inspection. */
5
6 #include <stdio.h>
7 #include <pthread.h>
8 #include <semaphore.h>
9 #include <assert.h>
10 #include <stdlib.h>
11 #include <unistd.h>
12
13 #define N_THREADS 3
14
15 static sem_t* my_sem_init(char*, int, unsigned);
16 static int my_sem_destroy(sem_t*);
17 static int my_sem_wait(sem_t*); //static int my_sem_post(sem_t*);
18
child_fn(void * semV)19 void* child_fn ( void* semV ) {
20 int r;
21 sem_t* sem = (sem_t*)semV;
22 r= my_sem_wait(sem); assert(!r);
23 return NULL;
24 }
25
main(void)26 int main ( void )
27 {
28 int r, i;
29 sem_t* sem;
30 pthread_t child[N_THREADS];
31
32 sem= my_sem_init("sem1", 0, N_THREADS); assert(sem);
33
34 for (i = 0; i < N_THREADS; i++) {
35 r= pthread_create( &child[i], NULL, child_fn, sem );
36 assert(!r);
37 }
38
39 for (i = 0; i < N_THREADS; i++) {
40 r= pthread_join( child[i], NULL );
41 assert(!r);
42 }
43
44 r= my_sem_destroy(sem); assert(!r);
45 return 0;
46 }
47
48
my_sem_init(char * identity,int pshared,unsigned count)49 static sem_t* my_sem_init (char* identity, int pshared, unsigned count)
50 {
51 sem_t* s;
52
53 #if defined(VGO_linux) || defined(VGO_solaris)
54 s = malloc(sizeof(*s));
55 if (s) {
56 if (sem_init(s, pshared, count) < 0) {
57 perror("sem_init");
58 free(s);
59 s = NULL;
60 }
61 }
62 #elif defined(VGO_darwin)
63 char name[100];
64 sprintf(name, "anonsem_%s_pid%d", identity, (int)getpid());
65 name[ sizeof(name)-1 ] = 0;
66 if (0) printf("name = %s\n", name);
67 s = sem_open(name, O_CREAT | O_EXCL, 0600, count);
68 if (s == SEM_FAILED) {
69 perror("sem_open");
70 s = NULL;
71 }
72 #else
73 # error "Unsupported OS"
74 #endif
75
76 return s;
77 }
78
my_sem_destroy(sem_t * s)79 static int my_sem_destroy ( sem_t* s )
80 {
81 return sem_destroy(s);
82 }
83
my_sem_wait(sem_t * s)84 static int my_sem_wait(sem_t* s)
85 {
86 return sem_wait(s);
87 }
88
89 #if 0
90 static int my_sem_post(sem_t* s)
91 {
92 return sem_post(s);
93 }
94 #endif
95