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
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
#define TEST_MACROS
#include <shared/flags.h>
#include <shared/syscalls.h>
#include <user/app/init/tests/main.h>
#include <user/lib/stdlib.h>
static const char *pipe_msgs[2] = {"hello", "world"};
void test_pipe(void) {
handle_t ends[2];
char buf[16];
int ret;
/* test regular reads / writes */
assert(_syscall_pipe(ends, 0) >= 0);
if (!fork()) {
/* those repeated asserts ensure that you can't read/write to the wrong ends */
assert(_syscall_read(ends[1], buf, 16, 0) < 0);
assert(_syscall_write(ends[0], buf, 16, 0) < 0);
ret = _syscall_write(ends[1], pipe_msgs[0], 5, -1);
assert(ret == 5);
assert(_syscall_read(ends[1], buf, 16, 0) < 0);
assert(_syscall_write(ends[0], buf, 16, 0) < 0);
ret = _syscall_write(ends[1], pipe_msgs[1], 5, -1);
assert(ret == 5);
_syscall_exit(0);
} else {
assert(_syscall_read(ends[1], buf, 16, 0) < 0);
assert(_syscall_write(ends[0], buf, 16, 0) < 0);
ret = _syscall_read(ends[0], buf, 16, 0);
assert(ret == 5);
assert(!memcmp(buf, pipe_msgs[0], 5));
assert(_syscall_read(ends[1], buf, 16, 0) < 0);
assert(_syscall_write(ends[0], buf, 16, 0) < 0);
_syscall_read(ends[0], buf, 16, 0);
assert(ret == 5);
assert(!memcmp(buf, pipe_msgs[1], 5));
_syscall_await();
}
close(ends[0]);
close(ends[1]);
/* writing to pipes with one end closed */
assert(_syscall_pipe(ends, 0) >= 0);
for (int i = 0; i < 16; i++) {
if (!fork()) {
close(ends[1]);
assert(_syscall_read(ends[0], buf, 16, 0) < 0);
_syscall_exit(0);
}
}
close(ends[1]);
for (int i = 0; i < 16; i++)
_syscall_await();
close(ends[0]);
assert(_syscall_pipe(ends, 0) >= 0);
for (int i = 0; i < 16; i++) {
if (!fork()) {
close(ends[0]);
assert(_syscall_write(ends[1], buf, 16, 0) < 0);
_syscall_exit(0);
}
}
close(ends[0]);
for (int i = 0; i < 16; i++)
_syscall_await();
close(ends[1]);
/* queueing */
assert(_syscall_pipe(ends, 0) >= 0);
for (int i = 0; i < 16; i++) {
if (!fork()) {
assert(_syscall_write(ends[1], pipe_msgs[0], 5, -1) == 5);
_syscall_exit(0);
}
}
close(ends[1]);
for (int i = 0; i < 16; i++) {
assert(_syscall_read(ends[0], buf, sizeof buf, 0) == 5);
_syscall_await();
}
assert(_syscall_read(ends[0], buf, sizeof buf, 0) < 0);
close(ends[0]);
assert(_syscall_pipe(ends, 0) >= 0);
for (int i = 0; i < 16; i++) {
if (!fork()) {
memset(buf, 0, sizeof buf);
assert(_syscall_read(ends[0], buf, 5, -1) == 5);
assert(!memcmp(buf, pipe_msgs[1], 5));
_syscall_exit(0);
}
}
close(ends[0]);
for (int i = 0; i < 16; i++) {
assert(_syscall_write(ends[1], pipe_msgs[1], 5, -1) == 5);
_syscall_await();
}
assert(_syscall_write(ends[1], pipe_msgs[1], 5, -1) < 0);
close(ends[1]);
// not a to.do detect when all processes that can read are stuck on writing to the pipe and vice versa
// it seems like linux just lets the process hang endlessly.
}
|
