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
|
#include <sys/select.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define BIG_PIPE_SIZE 64*1024 /* From sys/pipe.h */
/*
* Test for the non-blocking big pipe bug (write(2) returning
* EAGAIN while select(2) returns the descriptor as ready for write).
*
* $FreeBSD$
*/
static void
write_frame(int fd, char *buf, unsigned long buflen)
{
fd_set wfd;
int i;
while (buflen) {
FD_ZERO(&wfd);
FD_SET(fd, &wfd);
i = select(fd+1, NULL, &wfd, NULL, NULL);
if (i < 0)
err(1, "select failed");
if (i != 1) {
errx(1, "select returned unexpected value %d\n", i);
exit(1);
}
i = write(fd, buf, buflen);
if (i < 0) {
if (errno != EAGAIN)
warn("write failed");
exit(1);
}
buf += i;
buflen -= i;
}
}
int
main(void)
{
/* any value over PIPE_SIZE should do */
char buf[BIG_PIPE_SIZE];
int i, flags, fd[2];
if (pipe(fd) < 0)
errx(1, "pipe failed");
flags = fcntl(fd[1], F_GETFL);
if (flags == -1 || fcntl(fd[1], F_SETFL, flags|O_NONBLOCK) == -1) {
printf("fcntl failed: %s\n", strerror(errno));
exit(1);
}
switch (fork()) {
case -1:
err(1, "fork failed: %s\n", strerror(errno));
break;
case 0:
close(fd[1]);
for (;;) {
/* Any small size should do */
i = read(fd[0], buf, 256);
if (i == 0)
break;
if (i < 0)
err(1, "read");
}
exit(0);
default:
break;
}
close(fd[0]);
memset(buf, 0, sizeof buf);
for (i = 0; i < 1000; i++)
write_frame(fd[1], buf, sizeof buf);
printf("ok\n");
exit(0);
}
|
