shm_limits.c

来自「linux 操作系统下对系统资源监控程序的编写」· C语言 代码 · 共 116 行

/* $Id: shm_limits.c,v 1.19 2003/10/19 16:55:32 carlos Exp $ */

/* Copyright (C) 1998-99 Martin Baulig
   This file is part of LibGTop 1.0.

   Contributed by Martin Baulig <[e-mail]>, August 1998.

   LibGTop is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License,
   or (at your option) any later version.

   LibGTop 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 LibGTop; see the file COPYING. If not, write to the
   Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.
*/

#include <glibtop.h>
#include <glibtop/error.h>
#include <glibtop/shm_limits.h>

#include <glibtop_suid.h>

#if defined(__bsdi__) && (_BSDI_VERSION < 199700)
/* Older versions of BSDI don't seem to have this. */

void
glibtop_init_shm_limits_p (glibtop *server)
{ }

void
glibtop_get_shm_limits_p (glibtop *server, glibtop_shm_limits *buf)
{
        glibtop_init_p (server, (1L << GLIBTOP_SYSDEPS_SHM_LIMITS), 0);

        memset (buf, 0, sizeof (glibtop_shm_limits));
}

#else

/* #define KERNEL to get declaration of `struct shminfo'. */

#if (defined(__FreeBSD__) && (__FreeBSD_version < 410000)) || defined(__bsdi__)
#define KERNEL 1
#else
#define _KERNEL 1
#endif

#include <sys/ipc.h>
#include <sys/shm.h>

static unsigned long _glibtop_sysdeps_shm_limits =
(1L << GLIBTOP_IPC_SHMMAX) + (1L << GLIBTOP_IPC_SHMMIN) +
(1L << GLIBTOP_IPC_SHMMNI) + (1L << GLIBTOP_IPC_SHMSEG) +
(1L << GLIBTOP_IPC_SHMALL);

/* The values in this structure never change at runtime, so we only
 * read it once during initialization. We have to use the name `_shminfo'
 * since `shminfo' is already declared external in <sys/shm.h>. */
static struct shminfo _shminfo;
  
/* nlist structure for kernel access */
static struct nlist nlst [] = {
	{ "_shminfo" },
	{ 0 }
};

/* Init function. */

void
glibtop_init_shm_limits_p (glibtop *server)
{
	if (kvm_nlist (server->machine.kd, nlst) < 0) {
		glibtop_warn_io_r (server, "kvm_nlist (shm_limits)");
		return;
	}
	
	if (kvm_read (server->machine.kd, nlst [0].n_value,
		      &_shminfo, sizeof (_shminfo)) != sizeof (_shminfo)) {
		glibtop_warn_io_r (server, "kvm_read (shminfo)");
		return;
	}

	server->sysdeps.shm_limits = _glibtop_sysdeps_shm_limits;
}

/* Provides information about sysv ipc limits. */

void
glibtop_get_shm_limits_p (glibtop *server, glibtop_shm_limits *buf)
{
	glibtop_init_p (server, (1L << GLIBTOP_SYSDEPS_SHM_LIMITS), 0);
	
	memset (buf, 0, sizeof (glibtop_shm_limits));

	if (server->sysdeps.shm_limits == 0)
		return;

	buf->shmmax = _shminfo.shmmax;
	buf->shmmin = _shminfo.shmmin;
	buf->shmmni = _shminfo.shmmni;
	buf->shmseg = _shminfo.shmseg;
	buf->shmall = _shminfo.shmall;

	buf->flags = _glibtop_sysdeps_shm_limits;
}

#endif /* either a newer BSDI or no BSDI at all. */