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/* $OpenBSD: mmap-sysctl-copyout.c,v 1.3 2021/12/13 16:56:50 deraadt Exp $ */
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <err.h>
#include <fcntl.h>
#include <stdlib.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#define FILE "sysctl-net.inet.tcp.stats"
#define CLIENT "/mnt/regress-nfs-client"
#define SERVER "/mnt/regress-nfs-server"
int
main(void)
{
char *p, path[PATH_MAX];
int mib[] = { CTL_NET, PF_INET, IPPROTO_TCP, TCPCTL_STATS };
u_int miblen = sizeof(mib) / sizeof(mib[0]);
struct tcpstat stats;
int fd;
size_t len;
ssize_t n;
/*
* Initialize file on NFS server.
*/
snprintf(path, sizeof(path), "%s/%s", SERVER, FILE);
if ((fd = open(path, O_RDWR|O_CREAT|O_TRUNC, 0777)) == -1)
err(1, "open write '%s'", path);
len = sizeof(struct tcpstat);
memset(&stats, 0, len);
if ((n = write(fd, &stats, len)) == -1)
err(1, "write");
if ((size_t)n != len)
errx(1, "write not %zu: %zd", len, n);
if (close(fd) == -1)
err(1, "close read");
/*
* Map file on NFS client and write sysctl net.inet.tcp.stats into it.
*/
snprintf(path, sizeof(path), "%s/%s", CLIENT, FILE);
if ((fd = open(path, O_RDWR)) == -1)
err(1, "open mmap '%s'", path);
p = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (p == MAP_FAILED)
err(1, "mmap");
if (sysctl(mib, miblen, p, &len, NULL, 0) == -1)
err(1, "sysctl get stat");
if (len != sizeof(struct tcpstat))
errx(1, "len not %zu: %zu", sizeof(struct tcpstat), len);
if (close(fd) == -1)
err(1, "close mmap");
/*
* Read file from NFS server.
*/
snprintf(path, sizeof(path), "%s/%s", SERVER, FILE);
if ((fd = open(path, O_RDONLY)) == -1)
err(1, "open read '%s'", path);
if ((n = read(fd, &stats, len)) == -1)
err(1, "read");
if ((size_t)n != len)
errx(1, "read not %zu: %zd", len, n);
if (close(fd) == -1)
err(1, "close read");
return (0);
}
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