Re:Rust 1.32 released
by jcranmer on Thursday January 17, 2019 @03:54PM
(#18934552)
On x86 systems, a breakpoint is implemented by replacing the byte with the "int3" instruction. For Unix systems, this is the SIGTRAP signal. So invoke_debugger() that boils down to asm("int3") would suffice, if you were already on a debugger.
Well, the trouble is knowing if you need to spawn a debugger. On Windows, there's a nice API for checking if you're being debugged (IsDebuggerPresent). On Linux, you have to read /proc/self/status to see if there is somebody running ptrace on you. On other Unixes, well, the only trick is trying to spawn another process to ptrace you and hope it works.
Well, the trouble is knowing if you need to spawn a debugger. On Windows, there's a nice API for checking if you're being debugged (IsDebuggerPresent). On Linux, you have to read /proc/self/status to see if there is somebody running ptrace on you. On other Unixes, well, the only trick is trying to spawn another process to ptrace you and hope it works.
It is possible, just tricky.