Debugging Metamod:Source on Linux

Introduction

To debug your Metamod:Source plugin on Linux, you should have gdb (Gnu DeBugger) and g++ 3.4.

Steps

1. Compile your plugin with -O0 -g -ggdb3. This will ensure your plugin has debug symbols compiled in. You should not be using high optimization flags or stripping symbols (-s).
2. In your shell (for bash), type:

   export LD_LIBRARY_PATH=".:bin:$LD_LIBRARY_PATH"

3. In your directory that contains srcds_run, type:

   gdb srcds_i686

   • Note: this assumes that your processor is i686. There is also srcds_amd and srcds_i486 -- run the one that is best described by your CPU.
4. In GDB, type your startup command line prepended by "run", like so:

   run -game cstrike +map de_dust +ip 127.0.0.1 +maxplayers 16

5. Once your server crashes, you can use bt to see a backtrace. To jump to a particular frame of the backtrace, you can use frame <n>.

Notes

• To break into the debugger, use CTRL+C.
• To continue after breaking, use cont.
• To print an expression, use print <expr>. You can print address contents, C expressions, previous expression results, and variable contents if the names are available in the frame.
• For disassembling..
  • Use set disas intel for proper Intel assembly output.
  • Use display/i $pc to see the current eip and its disassembly.
    • Note - you only need to do this once, as GDB will show it constantly.
  • Use disas <addr|expr> to disassemble an address or expression.
  • Use info all to see the CPU register layout.
• Use step and next for stepping into and over lines of code (also s and n).
• Use stepi and nexti for stepping into and over individual instructions (also si and ni).