CONFIG_ELF_CORE
CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS
Busybox uses softlimit to set RLIMIT_CORE.
sysctl -w "kernel.core_pattern=/var/cores/%h-%e-%p.core"; mkdir /var/cores -p;
sysctl -w "kernel.core_pattern=/core";
sysctl -w "kernel.core_pattern=/tmp/core-%e-%s-%u-%g-%p-%t";
sysctl -w "kernel.core_uses_pid=1";
sysctl -w "fs.suid_dumpable=2";
cat /proc/sys/kernel/core_pattern;
cat /proc/sys/kernel/core_uses_pid;
cat /proc/sys/fs/suid_dumpable;
mount -t tmpfs tmpfs /tmp;
softlimit -c 1048576 /mnt/app/test &
killall -11 test
kill -s SIGSEGV 8257
ls -al /var/cores
ls -al /tmp
Linux Applications Debugging Techniques/Core files - Wikibooks, open books for an open world
http://en.wikibooks.org/wiki/Linux_Applications_Debugging_Techniques/Core_files
HowTo: Debug Crashed Linux Application Core Files Like A Pro - nixCraft
http://www.cyberciti.biz/tips/linux-core-dumps.html
core(5) - Linux manual page
http://man7.org/linux/man-pages/man5/core.5.html
How to: Enable/Generate/Debug Core Dump In Linux? » IT Sprite
http://www.itsprite.com/how-to-enablegeneratedebug-core-dump-in-linux/
linux - Who generate a core dump file? Kernel or glibc? - Stack Overflow
http://stackoverflow.com/questions/20969239/who-generate-a-core-dump-file-kernel-or-glibc
Linux: Understanding how much is malloc'ed in a coredump (Kevin Grigorenko's IBM WebSphere SWAT Blog)
https://www.ibm.com/developerworks/community/blogs/kevgrig/entry/linux_understanding_how_much_is_malloc_ed_in_a_coredump?lang=en
kernel/git/torvalds/linux.git - Linux kernel source tree
coredump: make core dump functionality optional
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=046d662f481830e652ac34cd112249adde16452a
How to handle SIGSEGV, but also generate a core dump - Alex on Linux
http://www.alexonlinux.com/how-to-handle-sigsegv-but-also-generate-core-dump
2014年8月8日 星期五
2014年8月6日 星期三
Linux Crash Dump
echo 1 > /proc/sys/kernel/sysrq #enable SysRq
echo c > /proc/sysrq-trigger #trigger Crash
Magic SysRq key - Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Magic_SysRq_key
linux - core dump not generated - Stack Overflow
http://stackoverflow.com/questions/6809227/core-dump-not-generated
google-coredumper - A neat tool for creating GDB readable coredumps from multithreaded applications - Google Project Hosting
http://code.google.com/p/google-coredumper/
eCrash: Debugging without Core Dumps | Linux Journal
http://www.linuxjournal.com/article/8724?page=0,0
Embedded Crash Handler | Free software downloads at SourceForge.net
http://sourceforge.net/projects/ecrash/
Documentation for Kdump - The kexec-based Crash Dumping Solution
https://www.kernel.org/doc/Documentation/kdump/kdump.txt
[Ubuntu] Kernel Crash Dump
https://help.ubuntu.com/12.04/serverguide/kernel-crash-dump.html
[Fedora] How to use kdump to debug kernel crashes - FedoraProject
http://fedoraproject.org/wiki/How_to_use_kdump_to_debug_kernel_crashes
[Red Hat] A quick overview of Linux kernel crash dump analysis
http://magazine.redhat.com/2007/08/15/a-quick-overview-of-linux-kernel-crash-dump-analysis/
[Red Hat] Crash
http://people.redhat.com/~anderson/
https://github.com/crash-utility/crash
Linux Kernel Crash Book
https://www.dropbox.com/s/ktbz9fy7qbwsyfa/www.dedoimedo.com-crash-book.pdf
2014年8月4日 星期一
sshd always wants to change password
It's solved for me by setting it to non-zero:
No, it's because the System time is not set correctly.
libbb/update_passwd.c
Use date to update the system should fix this issue:
lib.uclibc.buildroot - Re: sshd always wants to change password - msg#00125 - Recent Discussion OSDir.com
http://osdir.com/ml/lib.uclibc.buildroot/2007-05/msg00125.html
Linux Password & Shadow File Formats
http://www.tldp.org/LDP/lame/LAME/linux-admin-made-easy/shadow-file-formats.html
sshd:"PASSWORD":1:0:99999:7:::Or run the following every time after useradd or passwd:
sed -e 's/^\([^:]*:[^:]*:\)0:/\11:/' /etc/shadow -iIs it because busybox passwd always update the "last changed" field to 0?
No, it's because the System time is not set correctly.
libbb/update_passwd.c
/* "name:" + "new_passwd" + ":" + "change date" + ":rest of line" */So if system time is not set correctly, "last changed" field will always be 0 at the first day, and SSH will always asking for changing passwd.
fprintf(new_fp, "%s%s:%u%s\n", name_colon, new_passwd,
(unsigned)(time(NULL)) / (24*60*60), cp);
Use date to update the system should fix this issue:
date -s 201401010000.00This is not even busybox related. It might happened on any PC, just PC has battery and RTC and rarely lost the time.
lib.uclibc.buildroot - Re: sshd always wants to change password - msg#00125 - Recent Discussion OSDir.com
http://osdir.com/ml/lib.uclibc.buildroot/2007-05/msg00125.html
> >Here is the entry from my shadow file:
> >sshd:"PASSWORD":0:0:99999:7:::
>
> set the last changed field to non-null
Linux Password & Shadow File Formats
http://www.tldp.org/LDP/lame/LAME/linux-admin-made-easy/shadow-file-formats.html
smithj:Ep6mckrOLChF.:10063:0:99999:7:::As with the passwd file, each field in the shadow file is also separated with ":" colon characters, and are as follows:
- Username, up to 8 characters. Case-sensitive, usually all lowercase. A direct match to the username in the /etc/passwd file.
- Password, 13 character encrypted. A blank entry (eg. ::) indicates a password is not required to log in (usually a bad idea), and a ``*'' entry (eg. :*:) indicates the account has been disabled.
- The number of days (since January 1, 1970) since the password was last changed.
- The number of days before password may be changed (0 indicates it may be changed at any time)
- The number of days after which password must be changed (99999 indicates user can keep his or her password unchanged for many, many years)
- The number of days to warn user of an expiring password (7 for a full week)
- The number of days after password expires that account is disabled
- The number of days since January 1, 1970 that an account has been disabled
- A reserved field for possible future use
2014年8月1日 星期五
夜宿海生館
國立海洋生物博物館
http://www.nmmba.gov.tw/index.aspx
夜宿海生館 : 活動介紹
http://sleepover.aquarium.com.tw/zh-tw/?Psn=10300
海生館-訂購流程
http://sleepover.aquarium.com.tw/zh-tw/?Psn=10324
夜宿海生館 活動參加需知
http://sleepover.aquarium.com.tw/upload/Vd_489/File/103-02-12.pdf
夜宿海生館>夜宿報名
http://www.aquarium.com.tw/nightsleep.php
http://www.nmmba.gov.tw/index.aspx
夜宿海生館 : 活動介紹
http://sleepover.aquarium.com.tw/zh-tw/?Psn=10300
海生館-訂購流程
http://sleepover.aquarium.com.tw/zh-tw/?Psn=10324
夜宿海生館 活動參加需知
http://sleepover.aquarium.com.tw/upload/Vd_489/File/103-02-12.pdf
夜宿海生館>夜宿報名
http://www.aquarium.com.tw/nightsleep.php