CVS log for src/lib/libc/sys/ptrace.2

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Keyword substitution: kv
Default branch: MAIN

s/unitialized/uninitialized/

Use more markup.

Introduce new ptrace(2) operations: PT_SET_SIGPASS and PT_GET_SIGPASS

They deliver the logic of bypassing selected signals directly to the
debuggee, without informing the debugger.

This can be used to implement the QPassSignals GDB/LLDB protocol.

This call can be useful to avoid signal races in ATF ptrace tests.

Mostly merge changes from HEAD upto 20200411

Document PT_LWPSTATUS and PT_LWPNEXT in ptrace(2)

Remove mentions of obsolete PT_LWPINFO.

Pull up following revision(s) (requested by kamil in ticket #326):

	lib/libc/sys/ptrace.2: revision 1.81

Document PT_STOP, update PT_KILL in the ptrace(2) man-page
Formatting by <mgorny>

Fix xref.

Document PT_STOP, update PT_KILL in the ptrace(2) man-page

Formatting by <mgorny>

Include pe_lwp member in 'struct ptrace_state'

Reviewed by kamil.

Fix thinko: syscalls -> signals

Improve/fix doc of PT_SETSTEP and PT_CLEARSTEP.

Reviewed by kamil.

Fix typo: SIGRAP -> SIGTRAP

Use Vt for variable types. New sentence, new line. Add a missing ')'.
Add/remove some articles or other missing words.

Implement PT_GETXSTATE and PT_SETXSTATE

Introduce two new ptrace() requests: PT_GETXSTATE and PT_SETXSTATE,
that provide access to the extended (and extensible) set of FPU
registers on amd64 and i386.  At the moment, this covers AVX (YMM)
and AVX-512 (ZMM, opmask) registers.  It can be easily extended
to cover further register types without breaking backwards
compatibility.

PT_GETXSTATE issues the XSAVE instruction with all kernel-supported
extended components enabled.  The data is copied into 'struct xstate'
(which -- unlike the XSAVE area itself -- has stable format
and offsets).

PT_SETXSTATE issues the XRSTOR instruction to restore the register
values from user-provided 'struct xstate'.  The function replaces only
the specific XSAVE components that are listed in 'xs_rfbm' field,
making it possible to issue partial updates.

Both syscalls take a 'struct iovec' pointer rather than a direct
argument.  This requires the caller to explicitly specify the buffer
size.  As a result, existing code will continue to work correctly
when the structure is extended (performing partial reads/updates).

Fix typo.

Try to make posix_spawn(3) note in ptrace(2) less confusing

Use Xr.

Document PTRACE_POSIX_SPAWN in man-page

Sync with HEAD

Update the ptrace(2) documentation

Document that TRAP_EXEC can be returned for PT_SYSCALL.
Document truncated byte transfers.

Synch with HEAD

Implement PTRACE_VFORK

Add support for tracing vfork(2) events in the context of ptrace(2).

This API covers other frontends to fork1(9) like posix_spawn(2) or clone(2),
if they cause parent to wait for exec(2) or exit(2) of the child.

Changes:
 - Add new argument to sigswitch() determining whether we need to acquire
   the proc_lock or whether it's already held.
 - Refactor fork1(9) for fork(2) and vfork(2)-like events.
   Call sigswitch() from fork(1) for forking or vforking parent, instead of
   emitting kpsignal(9). We need to emit the signal and suspend the parent,
   returning to user and relock proc_lock.
 - Add missing prototype for proc_stop_done() in kern_sig.c.
 - Make sigswitch a public function accessible from other kernel code
   including <sys/signalvar.h>.
 - Remove an entry about unimplemented PTRACE_VFORK in the ptrace(2) man page.
 - Permin PTRACE_VFORK in the ptrace(2) frontend for userland.
 - Remove expected failure for unimplemented PTRACE_VFORK tests in the ATF
   ptrace(2) test-suite.
 - Relax signal routing constraints under a debugger for a vfork(2)ed child.
   This intended to protect from signaling a parent of a vfork(2)ed child that
   called PT_TRACE_ME, but wrongly misrouted other signals in vfork(2)
   use-cases.

Add XXX comments about still existing problems and future enhancements:
 - correct vfork(2) + PT_TRACE_ME handling.
 - fork1(2) handling of scenarios when a process is collected in valid but
   rare cases.

All ATF ptrace(2) fork[1-8] and vfork[1-8] tests pass.

Fix PR kern/51630 by Kamil Rytarowski (myself).

Sponsored by <The NetBSD Foundation>

Pull up following revision(s) (requested by kamil in ticket #602):
	doc/CHANGES{,.prev}: revision 1.138
	sys/sys/ptrace.h: revision 1.63
	lib/libc/sys/ptrace.2: revision 1.68
	sys/kern/sys_ptrace_common.c: revision 1.35 (via patch)
	tests/lib/libc/sys/t_ptrace_wait.c: revision 1.23

Remove PT_GET_SIGMASK / PT_SET_SIGMASK

These operations cloned Linux's specific PTRACE_GETSIGMASK /
PTRACE_SETSIGMASK.

This feature was useful in applications like rr/criu/reptyr-like, where
the ptrace(2) interface is abused for the purpose of constructing an
arbitrary
process. It's not reliable and not portable. For the NetBSD case it will =
be
better to invent something dedicated for serializing and deserializing a
process with threads.

Noted on tech-toolchain@ and blog entry
"LLDB restoration and return to ptrace(2)"
https://blog.netbsd.org/tnf/entry/lldb_restoration_and_return_to

Remove PT_GET_SIGMASK / PT_SET_SIGMASK

These operations cloned Linux's specific PTRACE_GETSIGMASK / PTRACE_SETSIGMASK.
This feature was useful in applications like rr/criu/reptyr-like, where
the ptrace(2) interface is abused for the purpose of constructing an arbitrary
process. It's not reliable and not portable. For the NetBSD case it will be
better to invent something dedicated for serializing and deserializing a
process with threads.

Noted on tech-toolchain@ and blog entry

"LLDB restoration and return to ptrace(2)"
https://blog.netbsd.org/tnf/entry/lldb_restoration_and_return_to

Fix typo: s/interrput/interrupt/

Sync with HEAD

Sync with HEAD

Fix typo in previous (ptrace(2))

Document new calls and be more clear about PT_SYSCALL* in ptrace(2)

Document PT_SETSTEP and PT_CLEARSTEP in ptrace(2).

Try to explain more details of PT_SYSCALL and PT_SYSCALLEMU.

The description of PT_*STEP has been obtained from FreeBSD.

Sponsored by <The NetBSD Foundation>

Fix typos and some grammar

Correction in ptrace(2) about operations that emit signals

PT_STEP and PT_DETACH cannot emit signals
PT_CONTINUE and PT_SYSCALL can emit signals

Pointed out by <chs>

Sync with HEAD

Formatting fix.

Document PT_GETDBREGS and PT_SETDBRGS in ptrace(2)

Not this interface in MD part.
Explain design choices.

Sponsored by <The NetBSD Foundation>

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>

Introduce new interface in ptrace(2) - PT_GET_SIGMASK and PT_SET_SIGMASK

Add new interface to add ability to get/set signal mask of a tracee.
It has been inspired by Linux PTRACE_GETSIGMASK and PTRACE_SETSIGMASK, but
adapted for NetBSD API.

This interface is used for checkpointing software to set/restore context
of a process including signal mask like criu or just to track this property
in reverse-execution software like Record and Replay Framework (rr).


Add new ATF tests for this interface
====================================
getsigmask1:
    Verify that plain PT_SET_SIGMASK can be called

getsigmask2:
    Verify that PT_SET_SIGMASK reports correct mask from tracee

setsigmask1:
    Verify that plain PT_SET_SIGMASK can be called with empty mask

setsigmask2:
    Verify that sigmask is preserved between PT_GET_SIGMASK and
    PT_SET_SIGMASK

setsigmask3:
    Verify that sigmask is preserved between PT_GET_SIGMASK, process
    resumed and PT_SET_SIGMASK

setsigmask4:
    Verify that new sigmask is visible in tracee


Kernel ABI bump delayed as there are more interfaces to come in ptrace(2).

Sponsored by <The NetBSD Foundation>

Spelling fixes.

Make the PIOD_READ_AUXV operation more clear

Describe how to set piod_offs.

Sponsored by <The NetBSD Foundation>

Fix one markup issue and add initial HISTORY section

Import HISTORY notes from FreeBSD.

Sponsored by <The NetBSD Foundation>

Wording, macro use.

Document PTRACE_LWP_CREATE and PTRACE_LWP_EXIT in ptrace(2)

Sponsored by <The NetBSD Foundation>

Document PTRACE_VFORK and PTRACE_VFORK_DONE in ptrace(2)

PTRACE_VFORK - report vfork(2)-like operations and trace child
PTRACE_VFORK_DONE - report unblocking the parent after vfork(2)-like call

Note that PTRACE_VFORK is currently unimplemented and returns ENOTSUP.

Sponsored by <The NetBSD Foundation>

Correct man-page category of posix_spawn: is (3) not (2)

Document SIGTRAP with si_code TRAP_CHLD in ptrace(2)

Document the current behavior of TRAP_CHILD in NetBSD.
Add more notes on PTRACE_FORK events.

Sponsored by <The NetBSD Foundation>

Sync with HEAD.  (Note that most of these changes are simply $NetBSD$
tag issues.)

Add more notes explaining how debuggers work on NetBSD

Explain:
 - execve(2) handling and behavior, SIGTRAP & TRAP_EXEC
 - reference PaX MPROTECT restrictions for debuggers
 - software breakpoints handling and behavior, SIGTRAP & TRAP_BKPT
 - single step behavior, SIGTRAP & TRAP_TRACE
 - list predefined MI symbols for help debuggers in port specific headers
 - explain that PT_TRACE_ME does not send a SIGSTOP signal

Sponsored by <The NetBSD Foundation>

Document PT_SET_SIGINFO and PT_GET_SIGINFO in ptrace(2)

PT_SET_SIGINFO - fake signal information emitted to tracee
PT_GET_SIGINFO - read signal information routed to tracee

Sponsored by <The NetBSD Foundation>

Fix swapped text between PT_GET_PROCESS_STATE and PT_GET_EVENT_MASK

Sponsored by <The NetBSD Foundation>

ptrace(2): Document addr and data argument usage for PT_GET_PROCESS_STATE


The PT_GET_PROCESS_STATE call in ptrace(2) has the following usage of addr
and data:

    A pointer to this structure is passed in addr.  The data
    argument should be set to sizeof(struct ptrace_event).

Sponsored by <The NetBSD Foundation>

Reference siginfo(2) for a SIGCHLD signal

siginfo(2) describes appropriate signal specific information for SIGCHLD.

Sponsored by <The NetBSD Foundation>

Be consistent in using process' (vs process's).

ptrace(2): Document PT_GETVECREGS and PT_SETVECREGS (ppc ports specific)

Sponsored by <The NetBSD Foundation>

ptrace(2): Document PT_GETXMMREGS and PT_SETXMMREGS (i386 port specific)

Sponsored by <The NetBSD Foundation>

ptrace(2): Remove dead text, some of it commented in this file for years

For example PT_READ_U/PT_WRITE_U has been removed by <mycroft> in 19950126.

Sponsored by <The NetBSD Foundation>

Remove outdated note in the PT_DUMPCORE call of the ptrace(2) man-page

Currently the PT_DUMPCORE call requires process to be stopped, therefore it
no longer need to warn about stoped tracee to generate consistent data.

Sponsored by <The NetBSD Foundation>

Remove duplicated PT_DUMPCORE description in machine-specific calls section

This function is part of the general ptrace(2) interface.

Sponsored by <The NetBSD Foundation>

Sync with HEAD

Bump date for previous.

Document PT_SET_EVENT_MASK, PT_GET_EVENT_MASK and PT_GET_PROCESS_STATE

These descriptions are imported from OpenBSD.

Approved by <christos>

Sponsored by <The NetBSD Foundation>

document PIOD_READ_AUXV.

Rebase to HEAD as of a few days ago.

Rebase.

PR/49045: Tetsuya Isaki: remove remaining caddr_t in ptrace(2)

Document PT_SYSCALLEMU

Add offsets to the indentation in couple of places.

New sentence, new line. Sort errors. Remove trailing whitespace.

PR/43128: Paul Koning: Threads support in ptrace() is insufficient for gdb to
debug threaded live apps: Add an optional lwpid in PT_STEP and PT_CONTINUE to
indicate which lwp to operate on, and implement the glue required to make it
work.

Use .In for header files instead of .Ar Pa and variations.

Correct the struct name for PT_LWPINFO

the "addr" argument to ptrace(2) is void* now

Use more markup.

Add documentations for the 3 undocumented ptrace calls.

document PT_DUMPCORE.

\- is a minus, not -.

Fix typo in macro.

Use
.In header.h
instead of
.Fd #include \*[Lt]header.h\*[Gt]
Much easier to read and write, and supported by groff for ages.
Okayed by ross.

avaliable->available (Igor Sobrado, PR misc/19810)

Merge the nathanw_sa branch.

Catch up to -current.

New sentence, new line. From Robert Elz.

Catch up to -current.

The PT_IO operations are named PIOD_{READ,WRITE}_{I,D}, not
PIOD_OP_{READ,WRITE}_{I,D}.

Catch up to -current.

Document PT_IO.

Catch up to -current.

Generate <>& symbolically. I'm avoiding .../dist/... directories for now.

Catch up to -current.

Pull up revision 1.16 (requested by he):
  Fix a ptrace/execve race condition which could be used to modify
  the child process' image during execve.  This would be a security
  issue due to setuid programs.

Pull up revision 1.16 (requested by christos):
  Fix a ptrace/execve race condition which could be used to modify
  the child process' image during execve.  This would be a security
  issue due to setuid programs.

document that ptrace() will return EAGAIN if the process that we are trying
to ptrace is currently in execve().

Catch up to -current.

Sort sections, sort SEE ALSO, punctuation and miscellanous fixes.

Boring whitespace fixes.

Note that we do support single-stepping, as a machine-dependant feature.
Don't be SPARC-specific about what features we support. Document how
to determine which requests are supported.

Mention additional restriction on ptrace: you can't ptrace system processes since the assumptions made for normal processes don't always hold (such as p_pptr is non-NULL).

pullup rev.1.11 from trunk (approved by thorpej):
PT_DETACH treats addr & data the same way as PT_CONTINUE, actually

parameters addr & data are actually treated same way
for PT_DETACH and PT_CONTINUE - the only difference between them is that
the child is detached from the parent for PT_DETACH

Pull up to last week's -current.

Add a LIBRARY section to system call manual pages.  While it's clear that the
libraries contain stubs only (with minor exceptions a la pipe(2)), the purpose
of this section is to provide linkage information.

Add SEE ALSO section and xref sigaction(2) and signal(7)

Document new chroot-related restrictions on fchdir, chroot, and ptrace
made possible by the kernel getcwd infrastructure

Last of the .Os cleanups.  .Os is defined in the tmac.doc-common file,
so we shouldn't override it with versions in the manpages.  Wheee!

More missing .El's.

macroize BSD, NetBSD, FreeBSD and misc cleanup

alternate -> alternative, per PR 2643

comment out PT_READ_U, PT_WRITE_U, PT_SYSCALL descriptions

merge with lite, keeping most local changes.  clean up Ids

ptrace(2) by der mouse; not checked for accuracy