user/forktest.c


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

// Test that fork fails gracefully.
// Tiny executable so that the limit can be filling the proc table.

#include "kernel/types.h"
#include "kernel/stat.h"
#include "user/user.h"

#define N  1000

void
print(const char *s)
{
  write(1, s, strlen(s));
}

void
forktest(void)
{
  int n, pid;

  print("fork test\n");

  for(n=0; n<N; n++){
    pid = fork();
    if(pid < 0)
      break;
    if(pid == 0)
      exit(0);
  }

  if(n == N){
    print("fork claimed to work N times!\n");
    exit(1);
  }

  for(; n > 0; n--){
    if(wait(0) < 0){
      print("wait stopped early\n");
      exit(1);
    }
  }

  if(wait(0) != -1){
    print("wait got too many\n");
    exit(1);
  }

  print("fork test OK\n");
}

int
main(void)
{
  forktest();
  exit(0);
}