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/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2021 OpenVPN Inc <sales@openvpn.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* Maintain usage stats in a memory-mapped file
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#elif defined(_MSC_VER)
#include "config-msvc.h"
#endif
#include "syshead.h"
#if defined(ENABLE_MEMSTATS)
#include <sys/mman.h>
#include "error.h"
#include "misc.h"
#include "mstats.h"
#include "memdbg.h"
volatile struct mmap_stats *mmap_stats = NULL; /* GLOBAL */
static char mmap_fn[128];
void
mstats_open(const char *fn)
{
void *data;
ssize_t stat;
int fd;
struct mmap_stats ms;
if (mmap_stats) /* already called? */
{
return;
}
/* verify that filename is not too long */
if (strlen(fn) >= sizeof(mmap_fn))
{
msg(M_FATAL, "mstats_open: filename too long");
}
/* create file that will be memory mapped */
fd = open(fn, O_CREAT | O_TRUNC | O_RDWR, S_IRUSR | S_IWUSR);
if (fd < 0)
{
msg(M_ERR, "mstats_open: cannot open: %s", fn);
return;
}
/* set the file to the correct size to contain a
* struct mmap_stats, and zero it */
CLEAR(ms);
ms.state = MSTATS_ACTIVE;
stat = write(fd, &ms, sizeof(ms));
if (stat != sizeof(ms))
{
msg(M_ERR, "mstats_open: write error: %s", fn);
close(fd);
return;
}
/* mmap the file */
data = mmap(NULL, sizeof(struct mmap_stats), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (data == MAP_FAILED)
{
msg(M_ERR, "mstats_open: write error: %s", fn);
close(fd);
return;
}
/* close the fd (mmap now controls the file) */
if (close(fd))
{
msg(M_ERR, "mstats_open: close error: %s", fn);
}
/* save filename so we can delete it later */
strcpy(mmap_fn, fn);
/* save a global pointer to memory-mapped region */
mmap_stats = (struct mmap_stats *)data;
msg(M_INFO, "memstats data will be written to %s", fn);
}
void
mstats_close(void)
{
if (mmap_stats)
{
mmap_stats->state = MSTATS_EXPIRED;
if (munmap((void *)mmap_stats, sizeof(struct mmap_stats)))
{
msg(M_WARN | M_ERRNO, "mstats_close: munmap error");
}
platform_unlink(mmap_fn);
mmap_stats = NULL;
}
}
#endif /* if defined(ENABLE_MEMSTATS) */
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