CVS commit: src

["Kamil Rytarowski" <kamil%netbsd.org@localhost>]

Module Name:    src
Committed By:   kamil
Date:           Wed Feb 22 23:43:44 UTC 2017

Modified Files:
        src/lib/libc/sys: ptrace.2
        src/sys/kern: sys_ptrace_common.c
        src/sys/sys: ptrace.h
        src/tests/kernel: t_ptrace_wait.c

Log Message:
Introduce new ptrace(2) API to allow/prevent exection of LWP

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>


To generate a diff of this commit:
cvs rdiff -u -r1.59 -r1.60 src/lib/libc/sys/ptrace.2
cvs rdiff -u -r1.14 -r1.15 src/sys/kern/sys_ptrace_common.c
cvs rdiff -u -r1.56 -r1.57 src/sys/sys/ptrace.h
cvs rdiff -u -r1.70 -r1.71 src/tests/kernel/t_ptrace_wait.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.