Introduce new API for debuggers to allow/prevent execution of the specified
thread.
New ptrace(2) operations:
PT_RESUME Allow execution of a specified thread, change its state
from suspended to continued. The addr argument is unused.
The data argument specifies the LWP ID.
This call is equivalent to _lwp_continue(2) called by a
traced process. This call does not change the general
process state from stopped to continued.
PT_SUSPEND Prevent execution of a specified thread, change its state
from continued to suspended. The addr argument is unused.
The data argument specifies the requested LWP ID.
This call is equivalent to _lwp_suspend(2) called by a
traced process. This call does not change the general
process state from continued to stopped.
This interface is modeled after FreeBSD, however with NetBSD specific arguments
passed to ptrace(2) -- FreeBSD passes only thread id, NetBSD passes process and
thread id.
Extend PT_LWPINFO operation in ptrace(2) to report suspended threads. In the
ptrace_lwpinfo structure in pl_event next to PL_EVENT_NONE and PL_EVENT_SIGNAL
add new value PL_EVENT_SUSPENDED.
Add new errno(2) value EDEADLK that might be returned by ptrace(2). It prevents
dead-locking in a scenario of resuming a process or thread that is prevented
from execution. This fixes bug that old API was vulnerable to this scenario.
Kernel bump delayed till introduction of PT_GETDBREGS/PT_SETDBREGS soon.
Add new ATF tests:
- resume1
Verify that a thread can be suspended by a debugger and later
resumed by the debugger
- suspend1
Verify that a thread can be suspended by a debugger and later
resumed by a tracee
- suspend2
Verify that the while the only thread within a process is
suspended, the whole process cannot be unstopped
Sponsored by <The NetBSD Foundation>
f9b2093d06