I started the JBoss instance using the following command:
strace -o strace.out -ff ./startMethodServer.sh
Now i want to stop the generation of these strace.out files
How can i do this?
I have no clue about JBoss, but would advice to remove
-o strace.out
from invocation, since the the usual behaviour of many cli tools is to specify an output file with -o outputfile.
You'd have to stop the server and restart it without strace. The strace command has nothing to do with JBoss AS. It's part of the OS therefore it must be controlled by the OS.
The command
strace -o strace.out -ff ./startMethodServer.sh
is running the script ./startMethodServer.sh using strace. The strace program is writing the strace.out file, and will continue doing that until ./startMethodServer.sh exits. The only way to stop writing those files is to stop the strace process (which will stop ./startMethodServer.sh), and restart ./startMethodServer.sh without involving strace:
./startMethodServer.sh
Related
I can use gcore generating the core file of my application which was built with debug symbol. Out of curiosity, I tried using kill command to generated the core file, but no core is generated.
Here are the steps I took:
I first ran the following commands:
ulimit -c unlimited
sudo sysctl -w kernel.core_pattern=/tmp/core-%e.%p.%h.%t
Then start the application.
Then I tried the SIGABRT, SIGTRAP, SIGQUIT, there is no core file generated:
kill -SIGABRT `pidof my_app`
kill -SIGTRAP `pidof my_app`
kill -SIGQUIT `pidof my_app`
In all these runs, my_app was stoped, but there is no core file, locally or /tmp.
I am using Ubuntu 20.04.
Do you see anything wrong?
I am trying to locate a file used by a binary file during its execution. Using strace helps but its way too convoluted, macroed with grep is good enough, but does there exist an utility which can help me dump only files used by a binary?
you can try using:
lsof -p PID of the running process
lsof -c ssh would show all files opened by processes starting with the letter
Or try ltrace or maybe fuser
I've seen strace be used with some complex grep piping.. but it all depends on what exactly the end goal is.
You can also utilize the -e options in strace to filter, example is:
sudo strace -t -e trace=open,close,read,getdents,write,connect,accept whoami >/dev/null
and grep from there..
I am trying to see what would happen about system call when I running one command, but it seems those command after | can't be shown? like:
strace -f cat a.txt| cat
It seems strace and -f perimeter can show the whole process. I think the last part is in the child progress created by fork. Why and how to make it?
From the strace manual (emphasis mine).
-f Trace child processes as they are created by
currently traced processes as a result of the fork(2),
vfork(2) and clone(2) system calls.
The traced process in your case is the first cat process. The second cat process is not a child of the first cat process. The fork is done by the shell.
One way to achieve what you want is to trace the shell:
strace -f bash -c "cat a.txt| cat"
I want to monitor all the running processes using strace and when a process ends the output of the strace should be sent to a file.
And how to find every running proc PID. I also want to include process name in the output file.
$ sudo strace -p 1725 -o firefox_trace.txt
$ tail -f firefox_trace.txt
1725 would be the PID of the proccess you want to monitor (you can find the PID with "ps -C firefox-bin", for firefox in the example)
And firefox_trace.txt would be the output file !
The way to got would be to find every running proc PID, and use the command to write them in the output file !
Considering the doc,
-p pid
Attach to the process with the process ID pid and begin tracing. The
trace may be terminated at any time by a keyboard interrupt signal (
CTRL -C). strace will respond by detaching itself from the traced
process(es) leaving it (them) to continue running. Multiple -p options
can be used to attach to up to 32 processes in addition to command
(which is optional if at least one -p option is given).
Use -o to store the output to the file, or 2>&1 to redirect standard error to output, so you can filter it (grep) or redirect it into file (> file).
To monitor process without knowing its PID, but name, you can use pgrep command, e.g.
strace -p $(pgrep command) -o file.out
where command is your name of process (e.g. php, Chrome, etc.).
To learn more about parameters, check man strace.
Currently, I am taking up the long method of doing this by getting a list of processes using the following command
sudo ps -eo pid,command | grep -v grep | awk '{print $1}' > pids.txt
And then iterating through the process ids and executing in background the strace of each process and generating logs for each process with the process id in the log's extension
filename="$1"
while read -r line
do
chmod +x straceProgram.sh
./straceProgram.sh $line &
done < "$filename"
straceProgram.sh
pid="$1"
sudo strace -p $pid -o log.$pid
However, the problem with this approach is that if there is any new process which gets started, it will not be straced since the strace is on the process ids stored in the pids.txt during the first run.
The list of pids.txt can be updated with new process ids, however, I was inquisitive on running a strace at an operating system level which would strace all the activities being performed.
Could there be a better way to do this?
If your resulting filesystem is going to be a kernel filesystem driver, I would recommend using tracefs to gather the information you require. I would recommend against making this a kernel filesystem unless you have a lot of time and a lot of testing resources. It is not trivial.
If you want an easier, safer alternative, write your filesystem using fuse. The downside is that performance is not quite as good and there are a few places where it cannot be used, but it is often acceptable. Note that there is already an implementation of a logging filesystem under fuse.
use the strace -f (fork) option, also I suggest the -s 9999 for more details