kexec-tools: bump version and add support for crashdump kernel

split kexec-tools into two packages, kexec and kdump.
* kexec to simply execute a new kernel
* kdump is for loading and collecting debris of a crashed kernel with
  support for kdump forensics.

In order to properly support booting into a crashkernel, an init script
as well as UCI configuration has been added.
As modifying the kernel cmdline is required for this to work in x86
platforms use an uci-defaults script to modify /boot/grub/grub.cfg.

To test collecting crash information, use the 'c' sysrq-trigger, ie.
echo c > /proc/sysrq-trigger

This should result in the crash kernel being executed and (depending
on the configution) dmesg and/or vmcore getting saved.

To check if the crash kernel was loaded properly, use the 'status'
command of the kdump init script.

Signed-off-by: Daniel Golle <[email protected]>

package/boot/kexec-tools/Config.in

@@ -1,12 +1,5 @@
 menu "Configuration"
-	depends on PACKAGE_kexec-tools
-
-config KEXEC_TOOLS_kdump
-	bool
-	prompt "kdump support"
-	default n
-	help
-	  Include the kdump utility.
+	depends on PACKAGE_kexec
 
 config KEXEC_ZLIB
 	bool

package/boot/kexec-tools/Makefile

@@ -8,12 +8,12 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=kexec-tools
-PKG_VERSION:=2.0.14-rc1
+PKG_VERSION:=2.0.14
 PKG_RELEASE:=1
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=@KERNEL/linux/utils/kernel/kexec
-PKG_HASH:=3fc505ff8d8a2d24c68aac5e6b4783997d5a086966ff3de8b05a0ceb27e5e23b
+PKG_HASH:=ffb2e7e99d9d08754c6bc1922aed3c000094f318665d82a72ecc76c4ff1c0dc6
 
 PKG_FIXUP:=autoreconf
 
@@ -21,22 +21,49 @@ PKG_CONFIG_DEPENDS := CONFIG_KEXEC_ZLIB CONFIG_KEXEC_LZMA
 
 include $(INCLUDE_DIR)/package.mk
 
-define Package/kexec-tools
+define Package/kexec-tools/Default
   SECTION:=utils
   CATEGORY:=Utilities
-  DEPENDS:=@armeb||@arm||@i386||@x86_64||@powerpc64||@mipsel||@mips +KEXEC_ZLIB:zlib +KEXEC_LZMA:liblzma
-  TITLE:=Kernel boots kernel
   URL:=http://kernel.org/pub/linux/kernel/people/horms/kexec-tools/
   MAINTAINER:=Florian Fainelli <[email protected]>
-  MENU:=1
+endef
+
+define Package/kexec-tools
+  $(call Package/kexec-tools/Default)
+  TITLE:=kexec-tools transition meta package
+  DEPENDS:=+kexec
 endef
 
 define Package/kexec-tools/description
- kexec is a set of systems call that allows you to load
+ kexec is a set of system calls that allows you to load
  another kernel from the currently executing Linux kernel.
+ The kexec utility allows to load and boot another kernel.
 endef
 
-define Package/kexec-tools/config
+define Package/kexec
+  $(call Package/kexec-tools/Default)
+  TITLE:=Kernel boots kernel
+  DEPENDS:=\
+	@armeb||@arm||@i386||@x86_64||@powerpc64||@mipsel||@mips \
+	+KEXEC_ZLIB:zlib +KEXEC_LZMA:liblzma @KERNEL_KEXEC
+endef
+
+define Package/kexec/description
+ The kexec utility allows to load and boot another kernel.
+endef
+
+define Package/kdump
+  $(call Package/kexec-tools/Default)
+  TITLE:=Kernel crash analysis
+  DEPENDS:=+kexec @i386||@x86_64||@arm @KERNEL_CRASH_DUMP
+endef
+
+define Package/kdump/description
+ The kdump package allows to automatically boot into a
+ special kernel for analyzing kernel crashes using kdump.
+endef
+
+define Package/kexec/config
 	source "$(SOURCE)/Config.in"
 endef
 
@@ -65,24 +92,45 @@ CONFIGURE_VARS += \
 	BUILD_CC="$(HOSTCC)" \
 	TARGET_CC="$(TARGET_CC)"
 
-kexec-extra-sbin-$(CONFIG_KEXEC_TOOLS_kdump) += kdump
-
 define Build/Compile
 	$(MAKE) -C $(PKG_BUILD_DIR) DESTDIR="$(PKG_INSTALL_DIR)" all install
 endef
 
 define Package/kexec-tools/install
+	:
+endef
+
+define Package/kexec/install
 	$(INSTALL_DIR) $(1)/usr/sbin
-	$(INSTALL_BIN) \
-		$(addprefix $(PKG_INSTALL_DIR)/usr/sbin/, \
-			$(kexec-extra-sbin-y)) \
-		$(kexec-extra-bin-y) \
-		$(PKG_INSTALL_DIR)/usr/sbin/kexec \
-		$(1)/usr/sbin
+	$(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/sbin/kexec $(1)/usr/sbin
 
 # make a link for compatability with other distros
 	$(INSTALL_DIR) $(1)/sbin
 	$(LN) ../usr/sbin/kexec $(1)/sbin/kexec
 endef
 
+define Package/kdump/install
+	$(INSTALL_DIR) $(1)/usr/sbin $(1)/etc/init.d $(1)/etc/config $(1)/etc/uci-defaults
+	$(INSTALL_BIN) $(PKG_INSTALL_DIR)/usr/sbin/kdump $(PKG_INSTALL_DIR)/usr/sbin/vmcore-dmesg $(1)/usr/sbin
+	$(INSTALL_BIN) ./files/kdump.init $(1)/etc/init.d/kdump
+	$(INSTALL_BIN) ./files/kdump.defaults $(1)/etc/uci-defaults/kdump
+	$(INSTALL_CONF) ./files/kdump.config $(1)/etc/config/kdump
+endef
+
+define Package/kdump/prerm
+#!/bin/sh
+
+case $$(uname -m) in
+	i?86|x86_64)
+		if grep -q " crashkernel=" /boot/grub/grub.cfg; then
+			mount /boot -o remount,rw
+			sed -i 's/ crashkernel=[^ ]*//' /boot/grub/grub.cfg
+			mount /boot -o remount,ro
+		fi
+		;;
+esac
+endef
+
 $(eval $(call BuildPackage,kexec-tools))
+$(eval $(call BuildPackage,kexec))
+$(eval $(call BuildPackage,kdump))

package/boot/kexec-tools/files/kdump.config

@@ -0,0 +1,7 @@
+
+config kdump
+	option enabled '1'
+	option save_dmesg '1'
+	option save_vmcore '0'
+# using an external partition to store vmcore is highly recommended!
+#	option path '/mnt/crashdump'

package/boot/kexec-tools/files/kdump.defaults

@@ -0,0 +1,11 @@
+#!/bin/sh
+
+case $(uname -m) in
+	i?86|x86_64)
+		if ! grep -q crashkernel /boot/grub/grub.cfg; then
+			mount /boot -o remount,rw
+			sed -i 's/linux.*/& crashkernel=32M@32M/' /boot/grub/grub.cfg
+			mount /boot -o remount,ro
+		fi
+		;;
+esac

package/boot/kexec-tools/files/kdump.init

@@ -0,0 +1,182 @@
+#!/bin/sh /etc/rc.common
+
+START=41
+STOP=98
+
+EXTRA_COMMANDS="status"
+EXTRA_HELP="        status  Print crashkernel status"
+
+verify_kdump() {
+	local cfg="$1"
+	local enabled
+	local path
+	local save_vmcore
+	local save_dmesg
+
+	config_get_bool enabled "$cfg" enabled 1
+	config_get_bool save_dmesg "$cfg" save_dmesg 1
+	config_get_bool save_vmcore "$cfg" save_vmcore 0
+
+	[ "$enabled" -gt 0 ] || return 2
+
+	[ "$save_dmesg" -gt 0 ] || [ "$save_vmcore" -gt 0 ] || return 2
+
+	config_get path "$cfg" path "/"
+
+	[ -d "$path" ] || mkdir -p "$path" 2>/dev/null || return 1
+}
+
+run_kdump() {
+	local cfg="$1"
+	local enabled
+	local path
+	local save_vmcore
+	local save_dmesg
+
+	config_get_bool enabled "$cfg" enabled 1
+	[ "$enabled" -gt 0 ] || return
+
+	config_get_bool save_dmesg "$cfg" save_dmesg 1
+	config_get_bool save_vmcore "$cfg" save_vmcore 0
+	config_get path "$cfg" path "/"
+
+	timestamp=$(date "+%Y%m%dT%H%M%S")
+
+	if [ "$save_vmcore" -eq 1 ]; then
+		# would like 'sparse' but busybox doesn't support it
+		dd if=/proc/vmcore of="$path/vmcore-$timestamp" conv=fsync bs=1M
+	fi
+
+	if [ "$save_dmesg" -eq 1 ]; then
+		vmcore-dmesg /proc/vmcore > "$path/dmesg-$timestamp"
+	fi
+
+	sync
+	reboot -f
+}
+
+find_kernel() {
+	. /lib/functions.sh
+	local kernel
+
+	kernel="$BOOT_IMAGE"
+	if [ -r "$kernel" ]; then
+		echo $kernel
+		return 0
+	fi
+
+	kernel="$(find_mtd_part kernel)"
+	if [ -r "$kernel" ]; then
+		echo $kernel
+		return 0
+	fi
+
+	for voldir in /sys/class/ubi/ubi*_*; do
+		[ ! -e "$voldir" ] && continue
+		if [ "$(cat "${voldir}/name")" = "kernel" ]; then
+			kernel="/dev/$(basename "$voldir")"
+			echo $kernel
+			return 0
+		fi
+	done
+
+	return 1
+}
+
+load_crashkernel() {
+	local append_cmdline
+	local kernel
+
+	kernel="$(find_kernel)"
+	[ $? -gt 0 ] && return 1
+
+	case "$(uname -m)" in
+		i?86|x86_64)
+			grep -q "crashkernel=" /proc/cmdline || return 1
+			append_cmdline="1 irqpoll reset_devices maxcpus=1"
+			;;
+		arm*)
+			append_cmdline="1 maxcpus=1 reset_devices"
+			;;
+	esac
+	kexec -p "$kernel" --reuse-cmdline --append="$append_cmdline"
+	return $?
+}
+
+start() {
+	local retval
+
+	if [ ! -e /sys/kernel/kexec_crash_loaded ]; then
+		return 1
+	fi
+
+	if [ -e /proc/vmcore ]; then
+		config_load kdump
+		config_foreach run_kdump kdump
+	else
+		config_load kdump
+		config_foreach verify_kdump kdump
+		retval=$?
+		[ $retval = 1 ] && return 1
+		[ $retval = 0 ] && load_crashkernel
+		return $?
+	fi
+}
+
+stop() {
+	[ "$(cat /sys/kernel/kexec_crash_loaded)" = "1" ] || return
+
+	if [ -e "$BOOT_IMAGE" ]; then
+		kexec -p -u "$BOOT_IMAGE"
+	fi
+}
+
+status() {
+	local retval kernel
+
+	if [ ! -e /sys/kernel/kexec_crash_loaded ]; then
+		echo "crashdump not supported by kernel"
+		return
+	fi
+
+	if [ $(cat /sys/kernel/kexec_crash_size) -eq 0 ]; then
+		echo "memory for crashdump kernel not reserved!"
+		echo "check crashkernel= kernel cmdline parameter"
+		echo "(a reboot is required after installing kdump)"
+		return
+	fi
+
+	kernel="$(find_kernel)"
+	if [ $? -gt 0 ]; then
+		echo "cannot find kernel image"
+		return
+	else
+		echo "using kernel image $kernel"
+	fi
+
+	echo -n "kdump configuration is "
+	config_load kdump
+	retval=$?
+	if [ $retval = 0 ]; then
+		if [ "$(config_foreach echo kdump)" ]; then
+			config_foreach verify_kdump kdump
+			retval=$?
+		else
+			retval=1
+		fi
+	fi
+
+	if [ $retval = 0 ]; then
+		echo "valid"
+	elif [ $retval = 2 ]; then
+		echo "disabled"
+	else
+		echo "BROKEN"
+	fi
+
+	echo -n "kexec crash kernel "
+	if [ "$(cat /sys/kernel/kexec_crash_loaded)" = "0" ]; then
+		echo -n "not "
+	fi
+	echo "loaded"
+}