On windows, I can set globalflag to associate the start of a program with a debugger, so even when I call a program from a script, the debugger will start my program and is able to break at some code line.
So how to do this with gdb on linux? E.g, I've /home/my/a.out compiled with -g option by gcc, I wish who ever calls into a.out, it will be brought up by gdb:
Do I have to modify some system file to say, /home/my/a.out should be started by gdb and automatically attach?
How to make gdb auto-attach it and then break at 'main' and run?
Do I have to modify some system file to say, /home/my/a.out should be started by gdb and automatically attach?
You don't need to modify any system files to achive this. Modify /home/my/a.out instead.
Move original binary to a new name:
mv /home/my/a.out /home/my/a.out.orig
Replace /home/my/a.out with a shell script:
cat > /home/my/a.out <<'EOF'
#!/bin/sh
exec gdb -ex start --args /home/my/a.out.orig "$@"
EOF
chmmod +x /home/my/a.out
How to make gdb auto-attach it and then break at 'main' and run?
Above script will do that automatically.