1 /* $OpenBSD: mmap-sysctl-copyout.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.stats"
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_STATS };
32 u_int miblen = sizeof(mib) / sizeof(mib[0]);
33 struct tcpstat stats;
34 int fd;
35 size_t len;
36 ssize_t n;
37
38 /*
39 * Initialize file on NFS server.
40 */
41 snprintf(path, sizeof(path), "%s/%s", SERVER, FILE);
42 if ((fd = open(path, O_RDWR|O_CREAT|O_TRUNC, 0777)) == -1)
43 err(1, "open write '%s'", path);
44 len = sizeof(struct tcpstat);
45 memset(&stats, 0, len);
46 if ((n = write(fd, &stats, len)) == -1)
47 err(1, "write");
48 if ((size_t)n != len)
49 errx(1, "write not %zu: %zd", len, n);
50 if (close(fd) == -1)
51 err(1, "close read");
52
53 /*
54 * Map file on NFS client and write sysctl net.inet.tcp.stats into it.
55 */
56 snprintf(path, sizeof(path), "%s/%s", CLIENT, FILE);
57 if ((fd = open(path, O_RDWR)) == -1)
58 err(1, "open mmap '%s'", path);
59 p = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
60 if (p == MAP_FAILED)
61 err(1, "mmap");
62 if (sysctl(mib, miblen, p, &len, NULL, 0) == -1)
63 err(1, "sysctl get stat");
64 if (len != sizeof(struct tcpstat))
65 errx(1, "len not %zu: %zu", sizeof(struct tcpstat), len);
66 if (close(fd) == -1)
67 err(1, "close mmap");
68
69 /*
70 * Read file from NFS server.
71 */
72 snprintf(path, sizeof(path), "%s/%s", SERVER, FILE);
73 if ((fd = open(path, O_RDONLY)) == -1)
74 err(1, "open read '%s'", path);
75 if ((n = read(fd, &stats, len)) == -1)
76 err(1, "read");
77 if ((size_t)n != len)
78 errx(1, "read not %zu: %zd", len, n);
79 if (close(fd) == -1)
80 err(1, "close read");
81
82 return (0);
83 }
84