Add a new routine kvm_getcptime(3) for fetching the equivalent of

'kern.cp_time'.  For a live kernel it uses the sysctl.  For a crashdump,
it first checks to see if the kernel has a 'cp_time' global symbol.  If
it does, it uses that.  If that doesn't work, when it uses the recently
added kvm_getmaxcpu(3) and kvm_getpcpu(3) routines to walk all the CPUs
and sum up their counters.

MFC after:	1 week

4 files changed, 214 insertions, 3 deletions

diff --git a/lib/libkvm/Makefile b/lib/libkvm/Makefile
index 1204217..3ca8427 100644
--- a/lib/libkvm/Makefile
+++ b/lib/libkvm/Makefile
@@ -9,15 +9,16 @@ CFLAGS+=-DLIBC_SCCS -I${.CURDIR}
 CFLAGS+=-DSUN4V
 .endif
 
-SRCS=	kvm.c kvm_${MACHINE_ARCH}.c kvm_file.c kvm_getloadavg.c \
+SRCS=	kvm.c kvm_${MACHINE_ARCH}.c kvm_cptime.c kvm_file.c kvm_getloadavg.c \
 	kvm_getswapinfo.c kvm_pcpu.c kvm_proc.c
 .if ${MACHINE_ARCH} == "amd64" || ${MACHINE_ARCH} == "i386"
 SRCS+=	kvm_minidump_${MACHINE_ARCH}.c
 .endif
 INCS=	kvm.h
 
-MAN=	kvm.3 kvm_geterr.3 kvm_getfiles.3 kvm_getloadavg.3 kvm_getpcpu.3 \
-	kvm_getprocs.3 kvm_getswapinfo.3 kvm_nlist.3 kvm_open.3
+MAN=	kvm.3 kvm_getcptime.3 kvm_geterr.3 kvm_getfiles.3 kvm_getloadavg.3 \
+	kvm_getpcpu.3 kvm_getprocs.3 kvm_getswapinfo.3 kvm_nlist.3 kvm_open.3 \
+	kvm_read.3
 
 MLINKS+=kvm_getpcpu.3 kvm_getmaxcpu.3
 MLINKS+=kvm_getprocs.3 kvm_getargv.3 kvm_getprocs.3 kvm_getenvv.3
diff --git a/lib/libkvm/kvm.h b/lib/libkvm/kvm.h
index c60d211..0427bd1 100644
--- a/lib/libkvm/kvm.h
+++ b/lib/libkvm/kvm.h
@@ -70,6 +70,7 @@ struct kvm_swap {
 __BEGIN_DECLS
 int	  kvm_close(kvm_t *);
 char	**kvm_getargv(kvm_t *, const struct kinfo_proc *, int);
+int	  kvm_getcptime(kvm_t *, long *);
 char	**kvm_getenvv(kvm_t *, const struct kinfo_proc *, int);
 char	 *kvm_geterr(kvm_t *);
 char	 *kvm_getfiles(kvm_t *, int, int, int *);
diff --git a/lib/libkvm/kvm_cptime.c b/lib/libkvm/kvm_cptime.c
new file mode 100644
index 0000000..53dcdf3
--- /dev/null
+++ b/lib/libkvm/kvm_cptime.c
@@ -0,0 +1,132 @@
+/*-
+ * Copyright (c) 2008 Yahoo!, Inc.
+ * All rights reserved.
+ * Written by: John Baldwin <jhb@FreeBSD.org>
+ *
+ * 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.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE 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 THE 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("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/pcpu.h>
+#include <sys/resource.h>
+#include <sys/sysctl.h>
+#include <errno.h>
+#include <kvm.h>
+#include <limits.h>
+#include <stdlib.h>
+
+#include "kvm_private.h"
+
+static struct nlist kvm_cp_time_nl[] = {
+	{ "_cp_time" },			/* (deprecated) */
+	{ NULL },
+};
+
+#define	NL_CP_TIME		0
+
+static int kvm_cp_time_cached;
+
+static int
+_kvm_cp_time_init(kvm_t *kd)
+{
+
+	if (kvm_nlist(kd, kvm_cp_time_nl) < 0)
+		return (-1);
+	kvm_cp_time_cached = 1;
+}
+
+static int
+getsysctl(kvm_t *kd, const char *name, void *buf, size_t len)
+{
+	size_t nlen;
+
+	nlen = len;
+	if (sysctlbyname(name, buf, &nlen, NULL, 0) < 0) {
+		_kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
+		    strerror(errno));
+		return (-1);
+	}
+	if (nlen != len) {
+		_kvm_err(kd, kd->program, "sysctl %s has unexpected size",
+		    name);
+		return (-1);
+	}
+	return (0);
+}
+
+int
+kvm_getcptime(kvm_t *kd, long *cp_time)
+{
+	struct pcpu *pc;
+	int i, j, maxcpu;
+
+	if (kd == NULL) {
+		kvm_cp_time_cached = 0;
+		return (0);
+	}
+
+	if (ISALIVE(kd))
+		return (getsysctl(kd, "kern.cp_time", cp_time, sizeof(long) *
+		    CPUSTATES));
+
+	if (kvm_cp_time_cached == 0) {
+		if (_kvm_cp_time_init(kd) < 0)
+			return (-1);
+	}
+
+	/* If this kernel has a "cp_time[]" symbol, then just read that. */
+	if (kvm_cp_time_nl[NL_CP_TIME].n_value != 0) {
+		if (kvm_read(kd, kvm_cp_time_nl[NL_CP_TIME].n_value, cp_time,
+		    sizeof(long) * CPUSTATES) != sizeof(long) * CPUSTATES) {
+			_kvm_err(kd, kd->program, "cannot read cp_time array");
+			return (-1);
+		}
+		return (0);
+	}
+
+	/*
+	 * If we don't have that symbol, then we have to simulate
+	 * "cp_time[]" by adding up the individual times for each CPU.
+	 */
+	maxcpu = kvm_getmaxcpu(kd);
+	if (maxcpu < 0)
+		return (-1);
+	for (i = 0; i < CPUSTATES; i++)
+		cp_time[i] = 0;
+	for (i = 0; i < maxcpu; i++) {
+		pc = kvm_getpcpu(kd, i);
+		if (pc == NULL)
+			continue;
+		if (pc == (void *)-1)
+			return (-1);
+		for (j = 0; j < CPUSTATES; j++)
+			cp_time[j] += pc->pc_cp_time[j];
+		free(pc);
+	}
+	return (0);
+}
diff --git a/lib/libkvm/kvm_getcptime.3 b/lib/libkvm/kvm_getcptime.3
new file mode 100644
index 0000000..2ddc272
--- /dev/null
+++ b/lib/libkvm/kvm_getcptime.3
@@ -0,0 +1,77 @@
+.\" Copyright (c) 2008 Yahoo!, Inc.
+.\" All rights reserved.
+.\" Written by: John Baldwin <jhb@FreeBSD.org>
+.\"
+.\" 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.
+.\" 3. Neither the name of the author nor the names of any co-contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE 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 THE 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.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd August 19, 2008
+.Dt KVM_GETCPTIME 3
+.Os
+.Sh NAME
+.Nm kvm_getcptime
+.Nd fetch global CPU time statistics
+.Sh LIBRARY
+.Lb libkvm
+.Sh SYNOPSIS
+.In sys/param.h
+.In sys/resource.h
+.In sys/sysctl.h
+.In kvm.h
+.Ft int
+.Fn kvm_getcptime "kvm_t *kd" "long *cp_time"
+.Sh DESCRIPTION
+The
+.Fn kvm_getcptime
+function stores the global CPU time statistics from the kernel
+.Fa kd
+in the array of counters pointed to by
+.Fa cp_time .
+Note that
+.Fa cp_time
+should point to an array of
+.Dv CPUSTATES
+long integers.
+The format of the counters is identical to that output by the
+.Va kern.cp_time
+sysctl.
+.Sh CACHING
+This function caches the nlist values for various kernel variables which it
+reuses in successive calls.
+You may call the function with
+.Fa kd
+set to
+.Dv NULL
+to clear this cache.
+.Sh RETURN VALUES
+The
+.Nm kvm_getcptime
+function returns 0 on success and -1 on failure.
+If an error occurs,
+then an error message may be retrieved via
+.Xr kvm_geterr 3 .
+.Sh SEE ALSO
+.Xr kvm 3