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authorrwatson <rwatson@FreeBSD.org>2001-02-23 18:49:16 +0000
committerrwatson <rwatson@FreeBSD.org>2001-02-23 18:49:16 +0000
commit78bbdcc2c47d0c8cca39617c5fb960c9d456ddfc (patch)
tree7815c39be0009545d300c0c5ccf404be7931fa85 /lib
parent9a2d215a5f08b9bb59d6d213ebe2bdff2ee4aa87 (diff)
downloadFreeBSD-src-78bbdcc2c47d0c8cca39617c5fb960c9d456ddfc.zip
FreeBSD-src-78bbdcc2c47d0c8cca39617c5fb960c9d456ddfc.tar.gz
Adapt libkvm_getswapinfo() to make use of recently committed vm and swap
sysctls exporting swap information. When running on a live kernel, the sysctl's will now be used instead of kvm_read, allowing consumers of this interface to run without privilege (setgid kmem). Retain the ability to run on coredumps, or on a kernel using kmem if explicitly pointed at one. A side effect of this change is that kvm_getswapinfo() is faster now in the general case. If the SWIF_DUMP_TREE flag is given (pstat -ss does this), the radix tree walker, which still uses kvm_read in any case, is invoked, and therefore does require privilege. Submitted by: Thomas Moestl <tmoestl@gmx.net> Reviewed by: freebsd-audit
Diffstat (limited to 'lib')
-rw-r--r--lib/libkvm/kvm_getswapinfo.c314
1 files changed, 254 insertions, 60 deletions
diff --git a/lib/libkvm/kvm_getswapinfo.c b/lib/libkvm/kvm_getswapinfo.c
index fe742ad..d6f8f3c 100644
--- a/lib/libkvm/kvm_getswapinfo.c
+++ b/lib/libkvm/kvm_getswapinfo.c
@@ -1,5 +1,6 @@
/*
* Copyright (c) 1999, Matthew Dillon. All Rights Reserved.
+ * Copyright (c) 2001, Thomas Moestl
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided under the terms of the BSD
@@ -22,6 +23,7 @@ static const char rcsid[] =
#include <sys/stat.h>
#include <sys/conf.h>
#include <sys/blist.h>
+#include <sys/sysctl.h>
#include <err.h>
#include <fcntl.h>
@@ -32,6 +34,9 @@ static const char rcsid[] =
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
+#include <limits.h>
+
+#include "kvm_private.h"
static struct nlist kvm_swap_nl[] = {
{ "_swapblist" }, /* new radix swap list */
@@ -48,11 +53,19 @@ static struct nlist kvm_swap_nl[] = {
static int kvm_swap_nl_cached = 0;
static int nswdev;
-static int unswdev;
+static int unswdev; /* number of found swap dev's */
static int dmmax;
static void getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary,
int swap_max, int flags);
+static int kvm_getswapinfo2(kvm_t *kd, struct kvm_swap *swap_ary,
+ int swap_max, int flags);
+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 *, char *, void *, int);
+static int getsysctl2(kvm_t *, char *, char *, char *, int, void *, int);
+
#define SVAR(var) __STRING(var) /* to force expansion */
#define KGET(idx, var) \
@@ -74,6 +87,17 @@ static void getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary,
return (0); \
}
+#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,
@@ -81,7 +105,10 @@ kvm_getswapinfo(
int swap_max,
int flags
) {
- int ti = 0;
+ int rv;
+#ifdef DEBUG_SWAPINFO
+ int i;
+#endif
/*
* clear cache
@@ -91,52 +118,69 @@ kvm_getswapinfo(
return(0);
}
- /*
- * namelist
- */
- if (kvm_swap_nl_cached == 0) {
- struct swdevt *sw;
-
- if (kvm_nlist(kd, kvm_swap_nl) < 0)
- return(-1);
+ rv = kvm_getswapinfo2(kd, swap_ary, swap_max, flags);
- /*
- * required entries
+ /* This is only called when the tree shall be dumped. It needs kvm. */
+ if (flags & SWIF_DUMP_TREE) {
+#ifdef DEBUG_SWAPINFO
+ /*
+ * sanity check: Sizes must be equal - used field must be
+ * 0 after this. Fill it with total-used before, where
+ * getswapinfo_radix will subtrat total-used.
+ * This will of course only work if there is no swap activity
+ * while we are working, so this code is normally not active.
*/
-
- if (
- kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
- kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
- kvm_swap_nl[NL_DMMAX].n_value == 0 ||
- kvm_swap_nl[NL_SWAPBLIST].n_type == 0
- ) {
- return(-1);
+ for (i = 0; i < unswdev; i++) {
+ swap_ary[i].ksw_used = swap_ary[i].ksw_total -
+ swap_ary[i].ksw_used;
}
-
- /*
- * get globals, type of swap
- */
-
- KGET(NL_NSWDEV, nswdev);
- KGET(NL_DMMAX, dmmax);
-
- /*
- * figure out how many actual swap devices are enabled
- */
-
- KGET(NL_SWDEVT, sw);
- for (unswdev = nswdev - 1; unswdev >= 0; --unswdev) {
- struct swdevt swinfo;
-
- KGET2(&sw[unswdev], &swinfo, sizeof(swinfo), "swinfo");
- if (swinfo.sw_nblks)
- break;
+#endif
+ getswapinfo_radix(kd, swap_ary, swap_max, flags);
+#ifdef DEBUG_SWAPINFO
+ for (i = 0; i < unswdev; i++) {
+ if (swap_ary[i].ksw_used != 0) {
+ fprintf(stderr, "kvm_getswapinfo: swap size "
+ "mismatch (%d blocks)!\n",
+ swap_ary[i].ksw_used
+ );
+ }
}
- ++unswdev;
+ /* This is fast enough now, so just do it again. */
+ rv = kvm_getswapinfo2(kd, swap_ary, swap_max, flags);
+#endif
+ }
+
+ return rv;
+}
- kvm_swap_nl_cached = 1;
+static int
+kvm_getswapinfo2(
+ kvm_t *kd,
+ struct kvm_swap *swap_ary,
+ int swap_max,
+ int flags
+) {
+ 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 ti = 0;
+
+ /*
+ * namelist
+ */
+ if (!nlist_init(kd))
+ return (-1);
{
struct swdevt *sw;
@@ -174,33 +218,19 @@ kvm_getswapinfo(
if (i < ti) {
swap_ary[i].ksw_total = ttl;
- swap_ary[i].ksw_used = ttl;
+ swap_ary[i].ksw_used = swinfo.sw_used;
swap_ary[i].ksw_flags = swinfo.sw_flags;
- if (swinfo.sw_dev == NODEV) {
- snprintf(
- swap_ary[i].ksw_devname,
- sizeof(swap_ary[i].ksw_devname),
- "%s",
- "[NFS swap]"
- );
- } else {
- snprintf(
- swap_ary[i].ksw_devname,
- sizeof(swap_ary[i].ksw_devname),
- "%s%s",
- ((flags & SWIF_DEV_PREFIX) ? _PATH_DEV : ""),
- devname(swinfo.sw_dev, S_IFCHR)
- );
- }
+ GETSWDEVNAME(swinfo.sw_dev,
+ swap_ary[i].ksw_devname, flags
+ );
}
if (ti >= 0) {
swap_ary[ti].ksw_total += ttl;
- swap_ary[ti].ksw_used += ttl;
+ swap_ary[ti].ksw_used += swinfo.sw_used;
}
}
}
- getswapinfo_radix(kd, swap_ary, swap_max, flags);
return(ti);
}
@@ -226,7 +256,9 @@ scanradix(
int flags
) {
blmeta_t meta;
+#ifdef DEBUG_SWAPINFO
int ti = (unswdev >= swap_max) ? swap_max - 1 : unswdev;
+#endif
KGET2(scan, &meta, sizeof(meta), "blmeta_t");
@@ -248,7 +280,9 @@ scanradix(
/*
* Leaf bitmap
*/
+#ifdef DEBUG_SWAPINFO
int i;
+#endif
if (flags & SWIF_DUMP_TREE) {
printf("%*.*s(0x%06x,%d) Bitmap %08x big=%d\n",
@@ -260,6 +294,7 @@ scanradix(
);
}
+#ifdef DEBUG_SWAPINFO
/*
* If not all allocated, count.
*/
@@ -280,6 +315,7 @@ scanradix(
}
}
}
+#endif
} else if (meta.u.bmu_avail == radix) {
/*
* Meta node if all free
@@ -291,6 +327,7 @@ scanradix(
radix
);
}
+#ifdef DEBUG_SWAPINFO
/*
* Note: both dmmax and radix are powers of 2. However, dmmax
* may be larger then radix so use a smaller increment if
@@ -312,6 +349,7 @@ scanradix(
swap_ary[ti].ksw_used -= tinc;
}
}
+#endif
} else if (meta.u.bmu_avail == 0) {
/*
* Meta node if all used
@@ -378,6 +416,11 @@ getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
struct blist *swapblist = NULL;
struct blist blcopy = { 0 };
+ if (!nlist_init(kd)) {
+ fprintf(stderr, "radix tree: nlist_init failed!\n");
+ return;
+ }
+
KGET(NL_SWAPBLIST, swapblist);
if (swapblist == NULL) {
@@ -412,3 +455,154 @@ getswapinfo_radix(kvm_t *kd, struct kvm_swap *swap_ary, int swap_max, int flags)
flags
);
}
+
+#define GETSYSCTL(kd, name, var) \
+ getsysctl(kd, name, &(var), sizeof(var))
+#define GETSYSCTL2(kd, pref, suff, buf, var) \
+ getsysctl2(kd, pref, suff, buf, sizeof(buf), &(var), \
+ sizeof(var))
+
+int
+kvm_getswapinfo_sysctl(
+ kvm_t *kd,
+ struct kvm_swap *swap_ary,
+ int swap_max,
+ int flags
+) {
+ int ti = 0;
+ udev_t dev;
+ char node[15];
+ char buf[20];
+ int used, ttl, i;
+
+ if (!GETSYSCTL(kd, "vm.nswapdev", unswdev))
+ return -1;
+
+ ti = unswdev;
+ if (ti >= swap_max)
+ ti = swap_max - 1;
+
+ if (ti >= 0)
+ bzero(swap_ary, sizeof(struct kvm_swap) * (ti + 1));
+
+ if (!GETSYSCTL(kd, "vm.dmmax", dmmax))
+ return -1;
+
+ for (i = 0; i < unswdev; ++i) {
+ if (snprintf(node, sizeof(node), "vm.swapdev%d.", i) >=
+ sizeof(node)) {
+ _kvm_err(kd, kd->program, "XXX: node buffer too small");
+ return -1;
+ }
+
+ if (!GETSYSCTL2(kd, node, "nblks", buf, ttl))
+ return -1;
+ if (!GETSYSCTL2(kd, node, "used", buf, used))
+ return -1;
+ ttl -= dmmax;
+
+ if (i < ti) {
+ if (!GETSYSCTL2(kd, node, "dev", buf, dev))
+ return -1;
+ if (!GETSYSCTL2(kd, node, "flags", buf,
+ swap_ary[i].ksw_flags))
+ return -1;
+ swap_ary[i].ksw_total = ttl;
+ swap_ary[i].ksw_used = used;
+ GETSWDEVNAME(dev, swap_ary[i].ksw_devname, flags);
+ }
+ if (ti >= 0) {
+ swap_ary[ti].ksw_total += ttl;
+ swap_ary[ti].ksw_used += used;
+ }
+ }
+
+ return(ti);
+}
+
+static int
+nlist_init (
+ kvm_t *kd
+) {
+ struct swdevt *sw;
+
+ if (kvm_swap_nl_cached)
+ return (1);
+
+ if (kvm_nlist(kd, kvm_swap_nl) < 0)
+ return (0);
+
+ /*
+ * required entries
+ */
+ if (
+ kvm_swap_nl[NL_SWDEVT].n_value == 0 ||
+ kvm_swap_nl[NL_NSWDEV].n_value == 0 ||
+ kvm_swap_nl[NL_DMMAX].n_value == 0 ||
+ kvm_swap_nl[NL_SWAPBLIST].n_type == 0
+ ) {
+ return (0);
+ }
+
+ /*
+ * get globals, type of swap
+ */
+ KGET(NL_NSWDEV, nswdev);
+ KGET(NL_DMMAX, dmmax);
+
+ /*
+ * figure out how many actual swap devices are enabled
+ */
+ KGET(NL_SWDEVT, sw);
+ for (unswdev = nswdev - 1; unswdev >= 0; --unswdev) {
+ struct swdevt swinfo;
+
+ KGET2(&sw[unswdev], &swinfo, sizeof(swinfo), "swinfo");
+ if (swinfo.sw_nblks)
+ break;
+ }
+ ++unswdev;
+
+ kvm_swap_nl_cached = 1;
+ return (1);
+}
+
+static int
+getsysctl (
+ kvm_t *kd,
+ char *name,
+ void *ptr,
+ int len
+) {
+ int nlen = len;
+ if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
+ _kvm_err(kd, kd->program, "cannot read sysctl %s", name);
+ return (0);
+ }
+ if (nlen != len) {
+ _kvm_err(kd, kd->program, "sysctl %s has unexpected size", name);
+ return (0);
+ }
+ return (1);
+}
+
+static int
+getsysctl2 (
+ kvm_t *kd,
+ char *pref,
+ char *suff,
+ char *buf,
+ int buflen,
+ void *ptr,
+ int len
+) {
+ if (strlcpy(buf, pref, buflen) >= buflen) {
+ _kvm_err(kd, kd->program, "getsysctl2: string buffer too small");
+ return (0);
+ }
+ if (strlcat(buf, suff, buflen) >= buflen) {
+ _kvm_err(kd, kd->program, "getsysctl2: string buffer too small");
+ return (0);
+ }
+ return getsysctl(kd, buf, ptr, len);
+}
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