1 /* $OpenBSD: mmap-sysctl-copyin.c,v 1.3 2021/12/13 16:56:50 deraadt Exp $ */
2
3 #include <sys/types.h>
4 #include <sys/mman.h>
5 #include <sys/queue.h>
6 #include <sys/socket.h>
7 #include <sys/sysctl.h>
8
9 #include <netinet/in.h>
10 #include <netinet/tcp.h>
11 #include <netinet/tcp_seq.h>
12 #include <netinet/tcp_timer.h>
13 #include <netinet/tcp_var.h>
14
15 #include <err.h>
16 #include <fcntl.h>
17 #include <stdlib.h>
18 #include <limits.h>
19 #include <stdio.h>
20 #include <string.h>
21 #include <unistd.h>
22
23 #define FILE "sysctl-net.inet.tcp.always_keepalive"
24 #define CLIENT "/mnt/regress-nfs-client"
25 #define SERVER "/mnt/regress-nfs-server"
26
27 int
main(void)28 main(void)
29 {
30 char *p, path[PATH_MAX];
31 int mib[] = { CTL_NET, PF_INET, IPPROTO_TCP, TCPCTL_ALWAYS_KEEPALIVE };
32 u_int miblen = sizeof(mib) / sizeof(mib[0]);
33 int fd, val;
34 size_t len;
35
36 /*
37 * Get current value of sysctl net.inet.tcp.always_keepalive
38 * and write it into a file on the NFS server.
39 */
40 snprintf(path, sizeof(path), "%s/%s", SERVER, FILE);
41 if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, 0777)) == -1)
42 err(1, "open write '%s'", path);
43 len = sizeof(int);
44 if (sysctl(mib, miblen, &val, &len, NULL, 0) == -1)
45 err(1, "sysctl get keepalive");
46 if (len != sizeof(int))
47 errx(1, "len is not %zu: %zu", sizeof(int), len);
48 if (write(fd, &val, len) == -1)
49 err(1, "write");
50 if (close(fd) == -1)
51 err(1, "close write");
52
53 /*
54 * Map file on NFS client and read value to
55 * sysctl net.inet.tcp.always_keepalive.
56 */
57 snprintf(path, sizeof(path), "%s/%s", CLIENT, FILE);
58 if ((fd = open(path, O_RDWR)) == -1)
59 err(1, "open mmap '%s'", path);
60 p = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
61 if (p == MAP_FAILED)
62 err(1, "mmap");
63 if (sysctl(mib, miblen, NULL, 0, p, sizeof(int)) == -1)
64 err(1, "sysctl set keepalive");
65 if (close(fd) == -1)
66 err(1, "close mmap");
67
68 return (0);
69 }
70