17:32 <p53ud0nym> Is there an easy way to call a bash command from a systemtap script? I would like to read a file into a string on an event.

17:39 <fche> p53ud0nym, you can queue code to be run

17:39 <fche> but not collect its output (directly)

17:39 <fche> 'cause that'd block the systemtap runtime (kernel?) until the process was done

17:40 <fche> see the system("echo hello") type command

17:40 <fche> now if you really wanted to collect its output ...

17:40 <fche> you could arrange for it to send it to the kernel some interesting way, such as via echoing into a procfs file, at which stap could receive it via a procfs.write probe

17:46 <p53ud0nym> fche: I don't need to collect it's output. However does `system()` command run serially inside systap? I have a command after the read which will kill the guest OS state.

17:47 <fche> see [man function::system]

17:47 <fche> The command is started in the background ....

17:48 <fche> IOW the probe handler that launches it can't even tell when it stops

17:48 <fche> (on purpose)

17:51 <p53ud0nym> hmm, looks like that won't work. I'm currently writing c kernel ODcode to read the file inline.

20:16 <fche> p53ud0nym, that's going to be nasty tricky too

20:16 <fche> would suggest a procfs intermediary

20:16 <fche> maybe we should draft such a sample script

21:47 <palmtenor> Hello guys~ I'm exploring the usage of SDT and currently looking at include/sys/sdt.h . What does the __ASSEMBLER__ flag indicates? Code looks quite different with or without that flag. I googled around but didn't find much reference to it

21:47 <palmtenor> Thanks a lot in ahead!

21:54 <fche> palmtenor, that's for use of the header file from assembly code

21:54 <fche> (that's rather unusual)

22:03 <palmtenor> fche: Thank you! That makes sense, but I didn't expect it could do that:)