text: /*
   * Copyright (c) 1999, Matthew Dillon.  All Rights Reserved.
   * Copyright (c) 2001, Thomas Moestl.  All Rights Reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD: releng/11.0/lib/libkvm/kvm_getswapinfo.c 291406 2015-11-27 18:58:26Z jhb $");
  
  #include <sys/param.h>
  #include <sys/time.h>
  #include <sys/stat.h>
  #include <sys/blist.h>
  #include <sys/sysctl.h>
  
  #include <vm/swap_pager.h>
  #include <vm/vm_param.h>
  
  #include <err.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <kvm.h>
  #include <nlist.h>
  #include <paths.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  #include <limits.h>
  
  #include "kvm_private.h"
  
  static struct nlist kvm_swap_nl[] = {
  	{ .n_name = "_swtailq" },	/* list of swap devices and sizes */
  	{ .n_name = "_dmmax" },		/* maximum size of a swap block */
  	{ .n_name = NULL }
  };
  
  #define NL_SWTAILQ	0
  #define NL_DMMAX	1
  
  static int kvm_swap_nl_cached = 0;
  static int unswdev;  /* number of found swap dev's */
  static int dmmax;
  
  static int  kvm_getswapinfo_kvm(kvm_t *, struct kvm_swap *, int, int);
  static int  kvm_getswapinfo_sysctl(kvm_t *, struct kvm_swap *, int, int);
  static int  nlist_init(kvm_t *);
  static int  getsysctl(kvm_t *, const char *, void *, size_t);
  
  #define KREAD(kd, addr, obj) \
  	(kvm_read(kd, addr, (char *)(obj), sizeof(*obj)) != sizeof(*obj))
  #define	KGET(idx, var)							\
  	KGET2(kvm_swap_nl[(idx)].n_value, var, kvm_swap_nl[(idx)].n_name)
  #define KGET2(addr, var, msg)						\
  	if (KREAD(kd, (u_long)(addr), (var))) {				\
  		_kvm_err(kd, kd->program, "cannot read %s", msg);	\
  		return (-1);						\
  	}
  
  #define GETSWDEVNAME(dev, str, flags)					\
  	if (dev == NODEV) {						\
  		strlcpy(str, "[NFS swap]", sizeof(str));		\
  	} else {							\
  		snprintf(						\
  		    str, sizeof(str),"%s%s",				\
  		    ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""),	\
  		    devname(dev, S_IFCHR)				\
  		);							\
  	}
  
  int
  kvm_getswapinfo(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
  {
  
  	/*
  	 * clear cache
  	 */
  	if (kd == NULL) {
  		kvm_swap_nl_cached = 0;
  		return(0);
  	}
  
  	if (ISALIVE(kd)) {
  		return kvm_getswapinfo_sysctl(kd, swap_ary, swap_max, flags);
  	} else {
  		return kvm_getswapinfo_kvm(kd, swap_ary, swap_max, flags);
  	}
  }
  
  int
  kvm_getswapinfo_kvm(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max,
      int flags)
  {
  	int i, ttl;
  	TAILQ_HEAD(, swdevt) swtailq;
  	struct swdevt *sp, swinfo;
  	struct kvm_swap tot;
  
  	if (!kd->arch->ka_native(kd)) {
  		_kvm_err(kd, kd->program,
  		    "cannot read swapinfo from non-native core");
  		return (-1);
  	}
  
  	if (!nlist_init(kd))
  		return (-1);
  
  	bzero(&tot, sizeof(tot));
  	KGET(NL_SWTAILQ, &swtailq);
  	sp = TAILQ_FIRST(&swtailq);
  	for (i = 0; sp != NULL; i++) {
  		KGET2(sp, &swinfo, "swinfo");
  		ttl = swinfo.sw_nblks - dmmax;
  		if (i < swap_max - 1) {
  			bzero(&swap_ary[i], sizeof(swap_ary[i]));
  			swap_ary[i].ksw_total = ttl;
  			swap_ary[i].ksw_used = swinfo.sw_used;
  			swap_ary[i].ksw_flags = swinfo.sw_flags;
  			GETSWDEVNAME(swinfo.sw_dev, swap_ary[i].ksw_devname,
  			     flags);
  		}
  		tot.ksw_total += ttl;
  		tot.ksw_used += swinfo.sw_used;
  		sp = TAILQ_NEXT(&swinfo, sw_list);
  	}
  
  	if (i >= swap_max)
  		i = swap_max - 1;
  	if (i >= 0)
  		swap_ary[i] = tot;
  
          return(i);
  }
  
  #define	GETSYSCTL(kd, name, var)					\
  	    getsysctl(kd, name, &(var), sizeof(var))
  
  /* The maximum MIB length for vm.swap_info and an additional device number */
  #define	SWI_MAXMIB	3
  
  int
  kvm_getswapinfo_sysctl(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max,
      int flags)
  {
  	int ti, ttl;
  	size_t mibi, len;
  	int soid[SWI_MAXMIB];
  	struct xswdev xsd;
  	struct kvm_swap tot;
  
  	if (!GETSYSCTL(kd, "vm.dmmax", dmmax))
  		return -1;
  
  	mibi = SWI_MAXMIB - 1;
  	if (sysctlnametomib("vm.swap_info", soid, &mibi) == -1) {
  		_kvm_err(kd, kd->program, "sysctlnametomib failed: %s",
  		    strerror(errno));
  		return -1;
  	}
  	bzero(&tot, sizeof(tot));
  	for (unswdev = 0;; unswdev++) {
  		soid[mibi] = unswdev;
  		len = sizeof(xsd);
  		if (sysctl(soid, mibi + 1, &xsd, &len, NULL, 0) == -1) {
  			if (errno == ENOENT)
  				break;
  			_kvm_err(kd, kd->program, "cannot read sysctl: %s.",
  			    strerror(errno));
  			return -1;
  		}
  		if (len != sizeof(xsd)) {
  			_kvm_err(kd, kd->program, "struct xswdev has unexpected "
  			    "size;  kernel and libkvm out of sync?");
  			return -1;
  		}
  		if (xsd.xsw_version != XSWDEV_VERSION) {
  			_kvm_err(kd, kd->program, "struct xswdev version "
  			    "mismatch; kernel and libkvm out of sync?");
  			return -1;
  		}
  
  		ttl = xsd.xsw_nblks - dmmax;
  		if (unswdev < swap_max - 1) {
  			bzero(&swap_ary[unswdev], sizeof(swap_ary[unswdev]));
  			swap_ary[unswdev].ksw_total = ttl;
  			swap_ary[unswdev].ksw_used = xsd.xsw_used;
  			swap_ary[unswdev].ksw_flags = xsd.xsw_flags;
  			GETSWDEVNAME(xsd.xsw_dev, swap_ary[unswdev].ksw_devname,
  			     flags);
  		}
  		tot.ksw_total += ttl;
  		tot.ksw_used += xsd.xsw_used;
  	}
  
  	ti = unswdev;
  	if (ti >= swap_max)
  		ti = swap_max - 1;
  	if (ti >= 0)
  		swap_ary[ti] = tot;
  
          return(ti);
  }
  
  static int
  nlist_init(kvm_t *kd)
  {
  
  	if (kvm_swap_nl_cached)
  		return (1);
  
  	if (kvm_nlist(kd, kvm_swap_nl) < 0)
  		return (0);
  
  	/* Required entries */
  	if (kvm_swap_nl[NL_SWTAILQ].n_value == 0) {
  		_kvm_err(kd, kd->program, "unable to find swtailq");
  		return (0);
  	}
  
  	if (kvm_swap_nl[NL_DMMAX].n_value == 0) {
  		_kvm_err(kd, kd->program, "unable to find dmmax");
  		return (0);
  	}
  
  	/* Get globals, type of swap */
  	KGET(NL_DMMAX, &dmmax);
  
  	kvm_swap_nl_cached = 1;
  	return (1);
  }
  
  static int
  getsysctl(kvm_t *kd, const char *name, void *ptr, size_t len)
  {
  	size_t nlen = len;
  	if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
  		_kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
  		    strerror(errno));
  		return (0);
  	}
  	if (nlen != len) {
  		_kvm_err(kd, kd->program, "sysctl %s has unexpected size", name);
  		return (0);
  	}
  	return (1);
  }
  