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/* $OpenBSD: mmap-sysctl-copyin.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.always_keepalive"
#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_ALWAYS_KEEPALIVE };
u_int miblen = sizeof(mib) / sizeof(mib[0]);
int fd, val;
size_t len;
/*
* Get current value of sysctl net.inet.tcp.always_keepalive
* and write it into a file on the NFS server.
*/
snprintf(path, sizeof(path), "%s/%s", SERVER, FILE);
if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, 0777)) == -1)
err(1, "open write '%s'", path);
len = sizeof(int);
if (sysctl(mib, miblen, &val, &len, NULL, 0) == -1)
err(1, "sysctl get keepalive");
if (len != sizeof(int))
errx(1, "len is not %zu: %zu", sizeof(int), len);
if (write(fd, &val, len) == -1)
err(1, "write");
if (close(fd) == -1)
err(1, "close write");
/*
* Map file on NFS client and read value to
* sysctl net.inet.tcp.always_keepalive.
*/
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, NULL, 0, p, sizeof(int)) == -1)
err(1, "sysctl set keepalive");
if (close(fd) == -1)
err(1, "close mmap");
return (0);
}
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