Add kdump_post and kdump_pre support

Original patch is from Amerigo, but it has changed a lot:
remove multi dump
refreshed with latest git for the dump instruction function restructure
fixed the behavior of do_kdump_pre, if kdump_pre fails it will reboot
update the docs
check the existance and executable of kdump_pre/post files,
also check the timestamp of them for rebuilding.

refresh patch,
Address comments from vivek:
s/hush/bash in docs
fix the copy-paste error in kdump post error message
s/reboot\/halt/reboot in kexec-kdump-howto.txt

Signed-off-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

dracut-kdump.sh

@@ -15,6 +15,8 @@ DD_BLKSIZE=512
 FINAL_ACTION="reboot -f"
 DUMP_RETVAL=0
 conf_file="/etc/kdump.conf"
+KDUMP_PRE=""
+KDUMP_POST=""
 
 export PATH=$PATH:$KDUMP_SCRIPT_DIR
 
@@ -32,6 +34,20 @@ do_default_action()
     $DEFAULT_ACTION
 }
 
+do_kdump_pre()
+{
+    if [ -n "$KDUMP_PRE" ]; then
+        "$KDUMP_PRE"
+    fi
+}
+
+do_kdump_post()
+{
+    if [ -n "$KDUMP_POST" ]; then
+        "$KDUMP_POST" "$1"
+    fi
+}
+
 add_dump_code()
 {
     DUMP_INSTRUCTION=$1
@@ -164,6 +180,12 @@ read_kdump_conf()
                 SSH_KEY_LOCATION=$config_val
             fi
             ;;
+        kdump_pre)
+            KDUMP_PRE="$config_val"
+            ;;
+        kdump_post)
+            KDUMP_POST="$config_val"
+            ;;
         default)
             case $config_val in
                 shell)
@@ -218,8 +240,20 @@ if [ -z "$DUMP_INSTRUCTION" ]; then
     add_dump_code "dump_rootfs"
 fi
 
+do_kdump_pre
+if [ $? -ne 0 ]; then
+    echo "kdump_pre script exited with non-zero status!"
+    $FINAL_ACTION
+fi
+
 $DUMP_INSTRUCTION
 DUMP_RETVAL=$?
+
+do_kdump_post $DUMP_RETVAL
+if [ $? -ne 0 ]; then
+    echo "kdump_post script exited with non-zero status!"
+fi
+
 if [ $DUMP_RETVAL -ne 0 ]; then
     do_default_action
 fi

dracut-module-setup.sh

@@ -156,6 +156,9 @@ kdump_install_conf() {
         net)
             kdump_install_net "$config_val"
             ;;
+        kdump_pre|kdump_post)
+            dracut_install $config_val
+            ;;
         esac
     done < /etc/kdump.conf
 

kdump.conf

@@ -51,10 +51,28 @@
 #			  For core_collector format details please refer to
 #			  kexec-kdump-howto.txt or kdump.conf manpage.
 #
+# kdump_post <binary | script>
+# 			- This directive allows you to run a specified
+# 			  executable just after the memory dump process
+# 			  terminates. The exit status from the dump process
+# 			  is fed to the kdump_post executable, which can be
+# 			  used to trigger different actions for success or
+# 			  failure.
+#
+# kdump_pre <binary | script>
+#			- works just like the kdump_post directive, but instead
+#			  of running after the dump process, runs immediately
+#			  before.  Exit status of this binary is interpreted
+#			  as follows:
+#			  0 - continue with dump process as usual
+#			  non 0 - reboot the system
+#
 # extra_bins <binaries | shell scripts>
 # 			- This directive allows you to specify additional
 # 			  binaries or shell scripts you'd like to include in
-# 			  your kdump initrd.
+# 			  your kdump initrd. Generally only useful in
+# 			  conjunction with a kdump_post binary or script that
+# 			  relies on other binaries or scripts.
 #
 # extra_modules <module(s)>
 # 			- This directive allows you to specify extra kernel
@@ -92,6 +110,8 @@
 path /var/crash
 #core_collector makedumpfile -c --message-level 1 -d 31
 #core_collector scp
+#kdump_post /var/crash/scripts/kdump-post.sh
+#kdump_pre /var/crash/scripts/kdump-pre.sh
 #extra_bins /usr/bin/lftp
 #extra_modules gfs2
 #default shell

kdump.conf.5

@@ -89,11 +89,41 @@ ie. "makedumpfile -R vmcore < vmcore.flat"
 
 .RE
 
+.B kdump_post <binary | script>
+.RS
+This directive allows you to run a specified
+executable just after the memory dump process
+terminates. The exit status from the dump process
+is fed to the kdump_post executable, which can be
+used to trigger different actions for success or
+failure.
+.PP
+Note that scripts written for use with this
+directive must use the /bin/bash interpreter
+.RE
+
+.B kdump_pre <binary | script>
+.RS
+Works just like the kdump_post directive, but instead
+of running after the dump process, runs immediately
+before.  Exit status of this binary is interpreted
+as follows:
+.PP
+0 - continue with dump process as usual
+.PP
+non 0 - reboot the system
+.PP
+Note that scripts written for this directive must use
+the /bin/bash interpreter
+.RE
+
 .B extra_bins <binaries | shell scripts>
 .RS
 This directive allows you to specify additional
 binaries or shell scripts you'd like to include in
-your kdump initrd.
+your kdump initrd. Generally only useful in
+conjunction with a kdump_post binary or script that
+relies on other binaries or scripts.
 .RE
 
 .B extra_modules <module(s)>

kdumpctl

@@ -101,8 +101,11 @@ function check_config()
 		image_time=0
 	fi
 
-
+	EXTRA_BINS=`grep ^kdump_post $KDUMP_CONFIG_FILE | cut -d\  -f2`
-	EXTRA_BINS=`grep ^extra_bins $KDUMP_CONFIG_FILE | cut -d\  -f2-`
+	CHECK_FILES=`grep ^kdump_pre $KDUMP_CONFIG_FILE | cut -d\  -f2`
+	EXTRA_BINS="$EXTRA_BINS $CHECK_FILES"
+	CHECK_FILES=`grep ^extra_bins $KDUMP_CONFIG_FILE | cut -d\  -f2-`
+	EXTRA_BINS="$EXTRA_BINS $CHECK_FILES"
 	files="$KDUMP_CONFIG_FILE $kdump_kernel $EXTRA_BINS"
 
 	check_exist "$files" && check_executable "$EXTRA_BINS"

kexec-kdump-howto.txt

@@ -403,11 +403,27 @@ example, 'path /data/coredumps' would lead to vmcore files being written to
 that the path option is ingnored if your kdump configuration results in the
 core being saved from the initscripts in the root filesystem.
 
+Kdump Post-Capture Executable
+
+It is possible to specify a custom script or binary you wish to run following
+an attempt to capture a vmcore. The executable is passed an exit code from
+the capture process, which can be used to trigger different actions from
+within your post-capture executable.
+
+Kdump Pre-Capture Executable
+
+It is possible to specify a custom script or binary you wish to run before
+capturing a vmcore. Exit status of this binary is interpreted:
+0 - continue with dump process as usual
+non 0 - reboot the system
+
 Extra Binaries
 
 If you have specific binaries or scripts you want to have made available
 within your kdump initrd, you can specify them by their full path, and they
 will be included in your kdump initrd, along with all dependent libraries.
+This may be particularly useful for those running post-capture scripts that
+rely on other binaries.
 
 Extra Modules