CODEWITHSUNDEEP
gdbsignals
Malvineous
Malvineous

Reputation: 27340

GDB: Ctrl+C doesn't interrupt process as it usually does but rather terminates the program

Normally when you run a program through GDB you can press Ctrl+C to interrupt it, e.g. if it gets stuck in an infinite loop and you want to get a backtrace.

I'm debugging a program (xmms2d as it happens) but in this program only, when I press Ctrl+C it gets treated as if GDB was not running - the program shuts down cleanly and then GDB tells me the program exited normally.

How do I get the usual GDB behaviour back, where Ctrl+C interrupts the program? Or is there another way to produce the same reaction in GDB as a Ctrl+C normally does?

Upvotes: 41

Views: 38166

Answers (6)

FairyFar
FairyFar

Reputation: 21

I had a similar problem and I have solved it.

First, write a gdb script, the file name is sighhandler.gdb. The script file is in the project directory:

gdb_sigwait/src/sighandler.gdb

Then, source the above script file in the gdb initialization file (~/.gdbinit), for example:

source ~/gdb_sigwait/src/sighandler.gdb

The gdb script is too long. So, I created a github project to introduce and store the related code: https://github.com/fairyfar/gdb_sigwait

Upvotes: 2

Resigned June 2023
Resigned June 2023

Reputation: 4947

Note that running GDB under rlwrap breaks its ability to intercept ^C correctly. If you are doing this, then try running it without rlwrap.

Upvotes: 1

Yankes
Yankes

Reputation: 2135

I had same problem caused by SDL signal handlers that interfere with gdb. One solution I find to workaround this when starting gdb:

start
call sigignore(2)
continue

Now all CTRL-C will be ignored by application.

If you attach to some process and want to restore it to original condition after debuging, you can do this:

set $oldcallback = signal(2, 0)
call sigignore(2)
continue

And when you are done:

call signal(2, $oldcallback)
detach

Upvotes: 4

sunil
sunil

Reputation: 507

In the gdb prompt you can do "handle SIGINT stop" so that gdb catches CTRL-C

Upvotes: 10

Sanjay
Sanjay

Reputation: 1

You can change GDB's input/output target using the following command:

gdb -tty = /dev/tty1

Upvotes: 0

Jared Robinson
Jared Robinson

Reputation: 386

I'll bet that xmms2d is using sigwait() to handle signals, which breaks gdb's ability to catch CTRL-C. See https://bugzilla.kernel.org/show_bug.cgi?id=9039

I got an idea for a workaround by reading Continue to debug after failed assertion on Linux? -- when I'm ready to break in gdb, I run "kill -TRAP <pid>" from another terminal window.

Upvotes: 37

Related Questions