[lttng-dev] [PATCH lttng-tools] Add core dump snapshot handler script
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Fri Jul 19 16:20:49 EDT 2013
merged, thanks!
* Christian Babeux (christian.babeux at efficios.com) wrote:
> This is a custom core dump program that will be called when a core dump occur.
> The program will save the core data in CORE_PATH and also, if a root session
> daemon is running, will record a snapshot of tracing data using the lttng
> command line utility.
>
> Refer to README for installation and testing instruction.
>
> Sample output of test script:
>
> Setup...
> Spawning a session daemon
> Session auto-20130626-224838 created.
> Kernel channel chan enabled for session auto-20130626-224838
> kernel event sched_switch created in channel chan
> Tracing started for session auto-20130626-224838
> Sleeping...
> Crashing...
> ./test.sh: line 35: 16980 Segmentation fault (core dumped)
> $(dirname $0)/crash
> Waiting for data availability
> Tracing stopped for session auto-20130626-224838
> Session auto-20130626-224838 destroyed
> Core dump and snapshot should hopefully be available in
> /tmp/lttng/{core,snapshot}.
>
> /tmp/lttng
> |-- core
> | `-- core.16980
> `-- snapshot
> `-- snapshot
> |-- chan_0
> |-- chan_1
> |-- chan_2
> |-- chan_3
> |-- chan_4
> |-- chan_5
> |-- chan_6
> |-- chan_7
> `-- metadata
>
> Signed-off-by: Christian Babeux <christian.babeux at efficios.com>
> ---
> configure.ac | 1 +
> extras/Makefile.am | 2 +-
> extras/core-handler/Makefile.am | 8 +++++
> extras/core-handler/README | 80 +++++++++++++++++++++++++++++++++++++++++
> extras/core-handler/crash.c | 25 +++++++++++++
> extras/core-handler/handler.sh | 72 +++++++++++++++++++++++++++++++++++++
> extras/core-handler/install.sh | 34 ++++++++++++++++++
> extras/core-handler/test.sh | 43 ++++++++++++++++++++++
> 8 files changed, 264 insertions(+), 1 deletion(-)
> create mode 100644 extras/core-handler/Makefile.am
> create mode 100644 extras/core-handler/README
> create mode 100644 extras/core-handler/crash.c
> create mode 100644 extras/core-handler/handler.sh
> create mode 100644 extras/core-handler/install.sh
> create mode 100644 extras/core-handler/test.sh
>
> diff --git a/configure.ac b/configure.ac
> index f4a3cd8..1a9e42d 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -322,6 +322,7 @@ AC_CONFIG_FILES([
> extras/bindings/Makefile
> extras/bindings/swig/Makefile
> extras/bindings/swig/python/Makefile
> + extras/core-handler/Makefile
> src/Makefile
> src/common/Makefile
> src/common/kernel-ctl/Makefile
> diff --git a/extras/Makefile.am b/extras/Makefile.am
> index 925dc2e..52de618 100644
> --- a/extras/Makefile.am
> +++ b/extras/Makefile.am
> @@ -1 +1 @@
> -SUBDIRS = bindings
> +SUBDIRS = bindings core-handler
> diff --git a/extras/core-handler/Makefile.am b/extras/core-handler/Makefile.am
> new file mode 100644
> index 0000000..eff5443
> --- /dev/null
> +++ b/extras/core-handler/Makefile.am
> @@ -0,0 +1,8 @@
> +AM_CFLAGS = -O2 -g
> +AM_LDFLAGS =
> +
> +noinst_PROGRAMS = crash
> +crash_SOURCES = crash.c
> +
> +noinst_SCRIPTS = handler.sh install.sh test.sh
> +EXTRA_DIST = handler.sh install.sh test.sh
> diff --git a/extras/core-handler/README b/extras/core-handler/README
> new file mode 100644
> index 0000000..cdfab11
> --- /dev/null
> +++ b/extras/core-handler/README
> @@ -0,0 +1,80 @@
> +LTTng core dump snapshot handler
> +Christian Babeux, June 2013
> +
> +This is a custom core dump program that will be called when a core dump occur.
> +The program will save the core data in CORE_PATH and also, if a root session
> +daemon is running, will record a snapshot of tracing data using the lttng
> +command line utility.
> +
> +The core dump snapshot handler can be installed by using the provided
> +install.sh script or by adding the appropriate program pipe line to
> +/proc/sys/kernel/core_pattern. Refer to core(5) for more information about
> +the Linux kernel core dump handling and custom handler mechanism.
> +
> +Installation:
> +
> +# ./install.sh
> +Backup current core_pattern in core_pattern.bkp.
> +Successfully installed core_pattern.
> +
> +How to use:
> +
> +You can use the provided test.sh script to test that the core dump snapshot
> +handler is working properly:
> +
> +# ./test.sh
> +Setup...
> +Spawning a session daemon
> +Session auto-20130626-224838 created.
> +Kernel channel chan enabled for session auto-20130626-224838
> +kernel event sched_switch created in channel chan
> +Tracing started for session auto-20130626-224838
> +Sleeping...
> +Crashing...
> +./test.sh: line 35: 16980 Segmentation fault (core dumped)
> +$(dirname $0)/crash
> +Waiting for data availability
> +Tracing stopped for session auto-20130626-224838
> +Session auto-20130626-224838 destroyed
> +Core dump and snapshot should hopefully be available in
> +/tmp/lttng/{core,snapshot}.
> +
> +# tree /tmp/lttng
> +/tmp/lttng
> +|-- core
> +| `-- core.16980
> +`-- snapshot
> + `-- snapshot
> + |-- chan_0
> + |-- chan_1
> + |-- chan_2
> + |-- chan_3
> + |-- chan_4
> + |-- chan_5
> + |-- chan_6
> + |-- chan_7
> + `-- metadata
> +
> +Chaining with other core dump handler:
> +
> +Some Linux distributions already use their own core dump handler
> +(such as systemd 'systemd-coredump' utility). It is possible to chain these
> +core dump utility with the core dump snapshot handler. In order to achieve
> +this, the core dump snapshot handler must be first in the chain (e.g.
> +installed in /proc/sys/kernel/core_pattern) and the other core dump
> +handler must be called from within the core dump snapshot handler script.
> +
> +Example (chaining with systemd systemd-coredump):
> +
> +# cat /proc/sys/kernel/core_pattern
> +|/path/to/lttng/handler.sh %p %u %g %s %t %h %e %E %c
> +
> +In LTTng handler.sh script:
> +
> +[...]
> +# Save core dump from stdin.
> +$MKDIR_BIN -p "${CORE_PATH}"
> +
> +# Optional, chain core dump handler with original systemd script.
> +$CAT_BIN - | /usr/lib/systemd/systemd-coredump $p $u $g $s $t $e
> +[...]
> \ No newline at end of file
> diff --git a/extras/core-handler/crash.c b/extras/core-handler/crash.c
> new file mode 100644
> index 0000000..2b9cf4a
> --- /dev/null
> +++ b/extras/core-handler/crash.c
> @@ -0,0 +1,25 @@
> +/*
> + * Copyright (C) 2013 - Christian Babeux <christian.babeux at efficios.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License, version 2 only,
> + * as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, write to the Free Software Foundation, Inc.,
> + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
> + */
> +
> +
> +#include <signal.h>
> +
> +int main(int argc, char *argv[])
> +{
> + raise(SIGSEGV);
> + return 0;
> +}
> diff --git a/extras/core-handler/handler.sh b/extras/core-handler/handler.sh
> new file mode 100644
> index 0000000..3026e52
> --- /dev/null
> +++ b/extras/core-handler/handler.sh
> @@ -0,0 +1,72 @@
> +#!/bin/sh
> +#
> +# Copyright (C) 2013 - Christian Babeux <christian.babeux at efficios.com>
> +#
> +# This program is free software; you can redistribute it and/or
> +# modify it under the terms of the GNU General Public License
> +# as published by the Free Software Foundation; only version 2
> +# of the License.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program; if not, write to the Free Software
> +# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
> +#
> +
> +# System binaries paths.
> +CAT_BIN="cat"
> +PGREP_BIN="pgrep"
> +MKDIR_BIN="mkdir"
> +LTTNG_BIN="lttng"
> +
> +# Core file settings.
> +CORE_PATH="/tmp/lttng/core"
> +CORE_PREFIX="core"
> +
> +# Folder where to save snapshot output.
> +# Can also be a remote URI.
> +SNAPSHOT_PATH="/tmp/lttng/snapshot"
> +SNAPSHOT_OUTPUT="file://${SNAPSHOT_PATH}"
> +
> +# Sessiond binary name.
> +SESSIOND_BIN_NAME="lttng-sessiond"
> +
> +# Core specifiers, see man core(5)
> +
> +p=$1 # PID of dumped process
> +u=$2 # (numeric) real UID of dumped process
> +g=$3 # (numeric) real GID of dumped process
> +s=$4 # number of signal causing dump
> +t=$5 # time of dump, expressed as seconds since the Epoch,
> + # 1970-01-01 00:00:00 +0000 (UTC)
> +h=$6 # hostname (same as nodename returned by uname(2))
> +e=$7 # executable filename (without path prefix)
> +E=$8 # pathname of executable, with slashes ('/') replaced
> + # by exclamation marks ('!').
> +c=$9 # core file size soft resource limit of crashing process
> + # (since Linux 2.6.24)
> +
> +# Save core dump from stdin.
> +$MKDIR_BIN -p "${CORE_PATH}"
> +$CAT_BIN - > "${CORE_PATH}/${CORE_PREFIX}.$p"
> +
> +# Optional, chain core dump handler with original systemd script.
> +#$CAT_BIN - | /usr/lib/systemd/systemd-coredump $p $u $g $s $t $e
> +
> +# TODO: Checking for a sessiond lockfile would be more appropriate.
> +if $PGREP_BIN -u root "${SESSIOND_BIN_NAME}" > /dev/null 2>&1
> +then
> + # Since we are called via the kernel coredump mechanism, we need to
> + # setup our environment manually.
> + #
> + # The lttng command line tool lookup $HOME to adjust the .lttngrc
> + # path. This is useful to have automatic session name lookup.
> + export HOME="/root"
> + $MKDIR_BIN -p "${SNAPSHOT_PATH}"
> + $LTTNG_BIN snapshot add-output "${SNAPSHOT_OUTPUT}" > /dev/null 2>&1
> + $LTTNG_BIN snapshot record > /dev/null 2>&1
> +fi
> diff --git a/extras/core-handler/install.sh b/extras/core-handler/install.sh
> new file mode 100644
> index 0000000..4e8d844
> --- /dev/null
> +++ b/extras/core-handler/install.sh
> @@ -0,0 +1,34 @@
> +#!/bin/sh
> +#
> +# Copyright (C) 2013 - Christian Babeux <christian.babeux at efficios.com>
> +#
> +# This program is free software; you can redistribute it and/or
> +# modify it under the terms of the GNU General Public License
> +# as published by the Free Software Foundation; only version 2
> +# of the License.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program; if not, write to the Free Software
> +# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
> +#
> +
> +CORE_PATTERN="/proc/sys/kernel/core_pattern"
> +CORE_HANDLER_PATH="$(dirname $(readlink -e $0))/handler.sh"
> +
> +cat ${CORE_PATTERN} > core_pattern.bkp
> +
> +echo "Backup current core_pattern in core_pattern.bkp."
> +
> +echo "|$CORE_HANDLER_PATH %p %u %g %s %t %h %e %E %c" > ${CORE_PATTERN}
> +
> +if [ $? -eq 0 ]
> +then
> + echo "Successfully installed core_pattern."
> +else
> + echo "Installation of core_pattern failed."
> +fi
> diff --git a/extras/core-handler/test.sh b/extras/core-handler/test.sh
> new file mode 100644
> index 0000000..9c73e2d
> --- /dev/null
> +++ b/extras/core-handler/test.sh
> @@ -0,0 +1,43 @@
> +#!/bin/sh
> +#
> +# Copyright (C) 2013 - Christian Babeux <christian.babeux at efficios.com>
> +#
> +# This program is free software; you can redistribute it and/or
> +# modify it under the terms of the GNU General Public License
> +# as published by the Free Software Foundation; only version 2
> +# of the License.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program; if not, write to the Free Software
> +# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
> +#
> +
> +LTTNG_BIN="/usr/bin/lttng"
> +
> +CHANNEL_NAME="chan"
> +EVENT_NAME="sched_switch"
> +
> +echo "Setup..."
> +$LTTNG_BIN create --no-output
> +$LTTNG_BIN enable-channel "${CHANNEL_NAME}" -k --overwrite --output mmap
> +$LTTNG_BIN enable-event "${EVENT_NAME}" -c "${CHANNEL_NAME}" -k
> +$LTTNG_BIN start
> +
> +echo "Sleeping..."
> +sleep 10
> +
> +echo "Crashing..."
> +$(dirname $0)/crash
> +
> +echo "Sleeping..."
> +sleep 10
> +
> +$LTTNG_BIN stop
> +$LTTNG_BIN destroy
> +
> +echo "Core dump and snapshot should hopefully be available in /tmp/lttng/{core,snapshot}."
> --
> 1.8.3.2
>
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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