Re: [systemd-devel] FixMe need a coredump HOOK
Hi Zbyszek, Thanks for your reply :) OK, it is enough to collect user space coredump info for bug reporter frontend :) 1. const char *field, the second parameter of sd_journal_get_data, is able to set filter to limit the entries, isn't it? 2. I simply init pollfd struct with fds[0].fd = sd_journal_get_fd(m_j) fds[0].events = sd_journal_get_events(m_j) https://github.com/AOSC-Dev/FixMe/blob/master/test/test_systemd_journal.c#L22 But my systemd_journal testcase print out no such file or directory error COREDUMP=ELF Please someone give me some advice, thanks a lot! Regards, Leslie Zhai xiang.z...@i-soft.com.cn On 2014年06月08日 05:00, Zbigniew Jędrzejewski-Szmek wrote: Hi, the coredump machinery provided by the kernel only works for user space processes. Kernel faults usually end in a traceback being printed to the console and are handled differently. To receive information about past and future coredumps stored in the journal you need to: 1. Add a filter which limits entries to MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1 (I think you already have this) 2. retrieve a journal file descriptor which can be used for polling with sd_journal_get_fd() 3. loop over existing entries (You also seem to have this implemented) 4. establish a loop which will poll for journal changes. sd_journal_wait() implements such a loop, but if you want to run this code from a different event loop, you should add the file descriptor received from sd_journal_get_fd() to this external event loop. This is described in some detail in the sd_journal_wait(3) man page. You can use 'journalctl -f MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1' as a general guide. HTH, Zbyszek ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] FixMe need a coredump HOOK
Hi Mantas, Thanks for your reply :) Yes, I use sd_journal_get_fd() API as Zbigniew mentioned https://github.com/AOSC-Dev/FixMe/blob/master/test/test_systemd_journal.c#L22 But sd_journal_get_data print out no such file or directory error COREDUMP=ELF https://github.com/AOSC-Dev/FixMe/blob/master/test/test_systemd_journal.c#L54 Please someone give me some advice, thanks a lot! Regards, Leslie Zhai xiang.z...@i-soft.com.cn On 2014年06月08日 07:18, Mantas Mikulėnas wrote: On Sat, Jun 7, 2014 at 8:49 AM, Leslie Zhai xiangzha...@gmail.com wrote: [...] But I do NOT know how to hook coredump in user space... I simply cat /proc/sys/kernel/core_pattern |/usr/lib/systemd/systemd-coredump %p %u %g %s %t %e Then systemd-coredump collector will be called (HOOKed), for example, BANG ... segfault occured in user or kernel space. but there is NO dbus interface provided for other App such as bug reporter frontend. so I have to inotify /var/log/journal/SUBDIR https://github.com/AOSC-Dev/FixMe/blob/master/test/qinotify/qinotify.cpp#L99 Please someone give me some advice, how to hook coredump in user/kernel space based on systemd or other LIB, thanks a lot! inotify is actually the official method for watching journal entries -- just not directly, but using the sd_journal_get_fd() API that Zbigniew mentioned... From http://www.freedesktop.org/wiki/Software/systemd/journal-files/: Clients intending to show a live view of the journal should use inotify() for this to watch for files changes. ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] FixMe need a coredump HOOK
On Sun, Jun 08, 2014 at 08:49:10PM +0800, Leslie Zhai wrote: Hi Zbyszek, Thanks for your reply :) OK, it is enough to collect user space coredump info for bug reporter frontend :) Hi, if you do polling yourself, sd_journal_wait() is unnecessary and harmful. 1. const char *field, the second parameter of sd_journal_get_data, is able to set filter to limit the entries, isn't it? You need to use two filters: - first, you want to only look at journal entries which have MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1. You do this by using sd_journal_add_match(). - second, once you have an entry of this type, it will usually have a COREDUMP= field. You can use sd_journal_get_data() to extract it. You already have this part. 2. I simply init pollfd struct with fds[0].fd = sd_journal_get_fd(m_j) fds[0].events = sd_journal_get_events(m_j) https://github.com/AOSC-Dev/FixMe/blob/master/test/test_systemd_journal.c#L22 But my systemd_journal testcase print out no such file or directory error COREDUMP=ELF Even if you limit yourself to entries with MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1, there's no guarantee that COREDUMP= field is attached to each of them. You have to take this into account. Zbyszek ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] FixMe need a coredump HOOK
Hi, the coredump machinery provided by the kernel only works for user space processes. Kernel faults usually end in a traceback being printed to the console and are handled differently. To receive information about past and future coredumps stored in the journal you need to: 1. Add a filter which limits entries to MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1 (I think you already have this) 2. retrieve a journal file descriptor which can be used for polling with sd_journal_get_fd() 3. loop over existing entries (You also seem to have this implemented) 4. establish a loop which will poll for journal changes. sd_journal_wait() implements such a loop, but if you want to run this code from a different event loop, you should add the file descriptor received from sd_journal_get_fd() to this external event loop. This is described in some detail in the sd_journal_wait(3) man page. You can use 'journalctl -f MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1' as a general guide. HTH, Zbyszek ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] FixMe need a coredump HOOK
On Sat, Jun 7, 2014 at 8:49 AM, Leslie Zhai xiangzha...@gmail.com wrote: [...] But I do NOT know how to hook coredump in user space... I simply cat /proc/sys/kernel/core_pattern |/usr/lib/systemd/systemd-coredump %p %u %g %s %t %e Then systemd-coredump collector will be called (HOOKed), for example, BANG ... segfault occured in user or kernel space. but there is NO dbus interface provided for other App such as bug reporter frontend. so I have to inotify /var/log/journal/SUBDIR https://github.com/AOSC-Dev/FixMe/blob/master/test/qinotify/qinotify.cpp#L99 Please someone give me some advice, how to hook coredump in user/kernel space based on systemd or other LIB, thanks a lot! inotify is actually the official method for watching journal entries -- just not directly, but using the sd_journal_get_fd() API that Zbigniew mentioned... From http://www.freedesktop.org/wiki/Software/systemd/journal-files/: Clients intending to show a live view of the journal should use inotify() for this to watch for files changes. -- Mantas Mikulėnas graw...@gmail.com ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
[systemd-devel] FixMe need a coredump HOOK
Hi systemd developers, I am a newbie of systemd, and I only read some source code such as systemd-timedated for SetTime SetTimezone via dbus interface :) And at present I need to develop a bug reporter frontend named FixMe https://github.com/AOSC-Dev/FixMe So I read about systemd-journald for being familiar with it :) and I just print out dump_list thanks to SD_JOURNAL_FOREACH_XXX https://github.com/AOSC-Dev/FixMe/blob/master/test/qinotify/qinotify.cpp#L68 But I do NOT know how to hook coredump in user space... I simply cat /proc/sys/kernel/core_pattern |/usr/lib/systemd/systemd-coredump %p %u %g %s %t %e Then systemd-coredump collector will be called (HOOKed), for example, BANG ... segfault occured in user or kernel space. but there is NO dbus interface provided for other App such as bug reporter frontend. so I have to inotify /var/log/journal/SUBDIR https://github.com/AOSC-Dev/FixMe/blob/master/test/qinotify/qinotify.cpp#L99 Please someone give me some advice, how to hook coredump in user/kernel space based on systemd or other LIB, thanks a lot! PS: what a PITY!!! I missed Lennart Poettering speech in 2014 GNOME Asia, I would ask the (or some) question directly in the meeting! Welcome to Beijing for HAPPY HACKING :) Regards, Leslie Zhai xiang.z...@i-soft.com.cn ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
