Core dump
m |
m |
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Line 64: | Line 64: | ||
| %<NUL> || '%' is dropped | | %<NUL> || '%' is dropped | ||
|} | |} | ||
+ | |||
+ | ===Permanent Configuration=== | ||
+ | You can add a line like this to <code>/etc/sysctl.conf</code>: | ||
+ | <source lang="text"> | ||
+ | kernel.core_pattern = "%e.core.%s.%p" | ||
+ | </source> | ||
==Analyzing the dump later== | ==Analyzing the dump later== |
Revision as of 18:33, 14 June 2012
To enable a core dumps, do this in a shell:
ulimit -c unlimited
Or this from C:
#include <sys/time.h> #include <sys/resource.h> void coredump_enable(void) { struct rlimit rlim; getrlimit(RLIMIT_CORE,&rlim); rlim.rlim_cur = rlim.rlim_max; setrlimit(RLIMIT_CORE,&rlim); } void coredump_disable(void) { struct rlimit rlim; getrlimit(RLIMIT_CORE,&rlim); rlim.rlim_cur = 0; setrlimit(RLIMIT_CORE,&rlim); }
After you call coredump_enable()
, if your program dies for any reason (Segfault, etc) then a core dump will be taken.
It will often be stored to ./code
but the naming schema can be changed.
BEWARE: once a dump has been taken, if the naming schema does not result in a unique name, then an existing dump (or file) will NOT be overwritten.
Contents |
Naming the core dumps
Run the following to see your current setting:
cat /proc/sys/kernel/core_pattern <source> And run the following (as root) to update it: <source lang="bash"> echo "%e.core.%s.%p" > /proc/sys/kernel/core_pattern
Putting a '|
' (pipe) before an executable path and parameters from below in here allows you to run a script on a crash! That is executed before the application is killed!
Be careful, that application is run as root, as a child of 'keventd'.
Info
Pattern replacement
%p | pid |
%% | output one '%' |
%u | uid |
%g | gid |
%s | signal number |
%t | UNIX time of dump |
%h | hostname |
%e | executable filename |
%<OTHER> | both are dropped |
%<NUL> | '%' is dropped |
Permanent Configuration
You can add a line like this to /etc/sysctl.conf
:
kernel.core_pattern = "%e.core.%s.%p"
Analyzing the dump later
Take your executable in the left hand, and the core in the right, and shove them at gdb:
gdb ${EXECUTABLE} ${COREDUMP}