dlt-daemon
DLT Core Dump Handler
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Overview
When a program crash occurs on the system, the Core Dump Handler is triggered to extract relevant information from the core dump generated by the system. It stores this extracted information in the ECU’s file system as Core Dump Handler Files. These files are transported via the DLT Filetransfer mechanism. The transferred information can be combined and integrated into the developer toolchain (gdb, Release SW, etc.).
Integration
To build the core dump handler
Add
-DWITH_DLT_COREDUMPHANDLER=ON -DTARGET_CPU_NAME={i686|x86_64}
options to cmake. The core dump handler code currently supports the i686 and x86_64 architecture.
Temporary activation as replacement for default crash handler until next reboot
As root (not sudo) execute the following:
echo "|/usr/local/bin/dlt-cdh %t %p %s %e" > /proc/sys/kernel/core_pattern
NOTE: replace /usr/local/bin with the path dlt-cdh has been installed to. This instructs the kernel to pipe a core dump as standard input to dlt-cdh together with the following parameters:
- %t time of dump
- %p PID of dumped process
- %s number of signal causing dump
- %e executable filename
See
man core
for details.
Persistent activation as replacement for default crash handler
In /usr/lib/sysctl.d/ the file 50-coredump.conf has to be created which is done automatically by
make install
Unfortunately - at least on Fedora systems - abrt has to be removed with
yum remove abrtd*
because it ruthlessly overwrites our change at every boot. The core dump handler can be activated then without reboot by running
sysctl -p /usr/lib/sysctl.d/50-coredump.conf
Configuration of DLT Filetransfer for usage with dlt-cdh
Make sure the following is set in the “Filetransfer Manager” section of /etc/dlt-system.conf:
...
FiletransferEnable = 1
...
FiletransferDirectory = /var/core
...
Generation of core dump
When a crash happens the kernel invokes dlt-cdh and passes it the core dump as standard input. dlt-cdh does the following tasks:
- check if enough disk space available
- create target directories if not existing:
- /var/core
- /var/core_tmp
- /tmp/.core_locks
- clean /var/core_tmp
- retrieve context data mainly from /proc fs of the crashed process to a temporary context file in text format
- initialise core dump
- read ELF headers and notes to temporary core dump output file
- move context file and core dump to /var/core
- create id which identifies the crash
After the files have been moved to /var/core the DLT Filetransfer mechanism ensures that they are sent to connected clients.
AUTHOR
Lutz Helwing <Lutz_Helwing (at) mentor (dot) com>
COPYRIGHT
Copyright (C) 2011 - 2015 BMW AG. License MPL-2.0: Mozilla Public License version 2.0 http://mozilla.org/MPL/2.0/.