Some Intel processors implement a Branch Trace Store (BTS) which GDB
uses for reverse execution support via the "record btrace bts"
command.
I have been unable to find a description of a similar feature in a
recent (April 2020) AMD64 architecture reference:
https://www.amd.com/system/files/TechDocs/40332.pdf
While it is the case that AMD processors have an LBR (last branch
record) bit in the DebugCtl MSR, it seems that it affects only four
MSRs when enabled. The names of these MSRs are LastBranchToIP,
LastBranchFromIP, LastIntToIP, and LastIntFromIP. I can find no
mention of anything more extensive. While looking at an Intel
architecture document, I noticed that Intel's P6 family from the
mid-90s had registers of the same name.
Therefore...
This commit disables "record btrace bts" support in GDB for AMD
processors.
Using the test case from gdb.base/break.exp, the sessions
below show the expected behavior (run on a machine with an
Intel processor) versus that on a machine with an AMD processor.
The AMD processor in question is reported as follows by "lscpu":
AMD Ryzen Threadripper 2950X 16-Core Processor . Finally, I'll
note that the AMD machine is actually a VM, but I see similar
behavior on both the virtualization host and the VM.
Intel machine - Desired behavior:
[kevinb@mohave gdb]$ ./gdb -q testsuite/outputs/gdb.base/break/break
Reading symbols from testsuite/outputs/gdb.base/break/break...
(gdb) start
Temporary breakpoint 1 at 0x401179: file /home/kevinb/sourceware-git/native-build/bld/../../binutils-gdb/gdb/testsuite/gdb.base/break.c, line 43.
Starting program: /home/kevinb/sourceware-git/native-build/bld/gdb/testsuite/outputs/gdb.base/break/break
Temporary breakpoint 1, main (argc=1, argv=0x7fffffffd748, envp=0x7fffffffd758)
at /home/kevinb/sourceware-git/native-build/bld/../../binutils-gdb/gdb/testsuite/gdb.base/break.c:43
43 if (argc == 12345) { /* an unlikely value < 2^16, in case uninited */ /* set breakpoint 6 here */
(gdb) record btrace
(gdb) b factorial
Breakpoint 2 at 0x40121b: file /home/kevinb/sourceware-git/native-build/bld/../../binutils-gdb/gdb/testsuite/gdb.base/break.c, line 63.
(gdb) c
Continuing.
Breakpoint 2, factorial (value=6)
at /home/kevinb/sourceware-git/native-build/bld/../../binutils-gdb/gdb/testsuite/gdb.base/break.c:63
63 if (value > 1) { /* set breakpoint 7 here */
(gdb) info record
Active record target: record-btrace
Recording format: Branch Trace Store.
Buffer size: 64kB.
Recorded 768 instructions in 22 functions (0 gaps) for thread 1 (process 19215).
(gdb) record function-call-history
13 do_lookup_x
14 _dl_lookup_symbol_x
15 _dl_fixup
16 _dl_runtime_resolve_xsavec
17 atoi
18 strtoq
19 ____strtoll_l_internal
20 atoi
21 main
22 factorial
(gdb) record instruction-history
759 0x00007ffff7ce0917 <____strtoll_l_internal+647>: pop %r15
760 0x00007ffff7ce0919 <____strtoll_l_internal+649>: retq
761 0x00007ffff7cdd064 <atoi+20>: add $0x8,%rsp
762 0x00007ffff7cdd068 <atoi+24>: retq
763 0x00000000004011b1 <main+75>: mov %eax,%edi
764 0x00000000004011b3 <main+77>: callq 0x401210 <factorial>
765 0x0000000000401210 <factorial+0>: push %rbp
766 0x0000000000401211 <factorial+1>: mov %rsp,%rbp
767 0x0000000000401214 <factorial+4>: sub $0x10,%rsp
768 0x0000000000401218 <factorial+8>: mov %edi,-0x4(%rbp)
AMD machine - Wrong behavior:
[kev@f32-1 gdb]$ ./gdb -q testsuite/outputs/gdb.base/break/break
Reading symbols from testsuite/outputs/gdb.base/break/break...
(gdb) start
Temporary breakpoint 1 at 0x401179: file /ironwood1/sourceware-git/f32-master/bld/../../worktree-master/gdb/testsuite/gdb.base/break.c, line 43.
Starting program: /mesquite2/sourceware-git/f32-master/bld/gdb/testsuite/outputs/gdb.base/break/break
Temporary breakpoint 1, main (argc=1, argv=0x7fffffffd5b8, envp=0x7fffffffd5c8)
at /ironwood1/sourceware-git/f32-master/bld/../../worktree-master/gdb/testsuite/gdb.base/break.c:43
43 if (argc == 12345) { /* an unlikely value < 2^16, in case uninited */ /* set breakpoint 6 here */
(gdb) record btrace
(gdb) b factorial
Breakpoint 2 at 0x40121b: file /ironwood1/sourceware-git/f32-master/bld/../../worktree-master/gdb/testsuite/gdb.base/break.c, line 63.
(gdb) c
Continuing.
Breakpoint 2, factorial (value=6)
at /ironwood1/sourceware-git/f32-master/bld/../../worktree-master/gdb/testsuite/gdb.base/break.c:63
63 if (value > 1) { /* set breakpoint 7 here */
(gdb) info record
Active record target: record-btrace
Recording format: Branch Trace Store.
Buffer size: 64kB.
warning: Recorded trace may be incomplete at instruction 7737 (pc = 0x405000).
warning: Recorded trace may be incomplete at instruction 7739 (pc = 0x0).
Recorded 7740 instructions in 46 functions (2 gaps) for thread 1 (process 1402911).
(gdb) record function-call-history
37 ??
38 values
39 some_enum_global
40 ??
41 some_union_global
42 some_variable
43 ??
44 [decode error (2): unknown instruction]
45 ??
46 [decode error (2): unknown instruction]
(gdb) record instruction-history
7730 0x0000000000404ff3: add %al,(%rax)
7731 0x0000000000404ff5: add %al,(%rax)
7732 0x0000000000404ff7: add %al,(%rax)
7733 0x0000000000404ff9: add %al,(%rax)
7734 0x0000000000404ffb: add %al,(%rax)
7735 0x0000000000404ffd: add %al,(%rax)
7736 0x0000000000404fff: .byte 0x0
7737 0x0000000000405000: Cannot access memory at address 0x405000
Lastly, I'll note that I see a lot of gdb.btrace failures without
this commit. Worse still, the results aren't always the same which
causes a lot of noise when comparing test results.
gdbsupport/ChangeLog:
* btrace-common.h (btrace_cpu_vendor): Add CV_AMD.
gdb/ChangeLog:
* nat/linux-btrace.c (btrace_this_cpu): Add check for AMD
processors.
(cpu_supports_bts): Add CV_AMD case.
The updated pending stop series introduced a regression in Windows
debugging. When stopped at a software breakpoint, we would adjust the
PC each time it was requested -- however, more than a single
adjustment is incorrect. This patch introduces a new flag that is
used to ensure the adjustment only happens a single time.
No similar change is needed in gdbserver, because it adjusts the PC in
a different way.
I still can't run the gdb test suite on Windows, but I can run the
internal AdaCore test suite there; and this fixes the regressions
there.
gdb/ChangeLog
2020-04-24 Tom Tromey <tromey@adacore.com>
* nat/windows-nat.h (struct windows_thread_info)
<pc_adjusted>: New member.
* windows-nat.c (windows_fetch_one_register): Check
pc_adjusted.
(windows_nat_target::get_windows_debug_event)
(windows_nat_target::wait): Set pc_adjusted.
Simon pointed out that the windows-nat sharing series broke the Cygwin
build. This patch fixes the problem, by moving the Cygwin-specific
code to a new handler function. This approach is taken because this
code calls find_pc_partial_function, which isn't available in
gdbserver.
gdb/ChangeLog
2020-04-16 Tom Tromey <tromey@adacore.com>
* windows-nat.c (windows_nat::handle_access_violation): New
function.
* nat/windows-nat.h (handle_access_violation): Declare.
* nat/windows-nat.c (handle_exception): Move Cygwin code to
windows-nat.c. Call handle_access_violation.
gdbserver/ChangeLog
2020-04-16 Tom Tromey <tromey@adacore.com>
* win32-low.cc (windows_nat::handle_access_violation): New
function.
The new code regarding pending stops only checks for EXCEPTION_BREAKPOINT,
but for WOW64 processes STATUS_WX86_BREAKPOINT is necessary as well.
Also, ignore_first_breakpoint is used now in nat/windows-nat.c as well,
but was not available there.
gdb/ChangeLog:
2020-04-10 Hannes Domani <ssbssa@yahoo.de>
* nat/windows-nat.c (STATUS_WX86_BREAKPOINT, STATUS_WX86_SINGLE_STEP):
Move to...
* nat/windows-nat.h (STATUS_WX86_BREAKPOINT, STATUS_WX86_SINGLE_STEP):
... here.
* windows-nat.c (windows_nat_target::get_windows_debug_event):
Check for STATUS_WX86_BREAKPOINT.
(windows_nat_target::wait): Same.
Now that last_wait_event is entirely handled in nat/windows-nat.c, it
can be made static.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* nat/windows-nat.h (last_wait_event): Don't declare.
(wait_for_debug_event): Update comment.
* nat/windows-nat.c (last_wait_event): Now static.
This moves the wait_for_debug_event helper function to
nat/windows-nat.c, and changes gdbserver to use it.
wait_for_debug_event is a wrapper for WaitForDebugEvent that also sets
last_wait_event when appropriate. This is needed to properly handle
queued stops.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (wait_for_debug_event): Move to
nat/windows-nat.c.
* nat/windows-nat.h (wait_for_debug_event): Declare.
* nat/windows-nat.c (wait_for_debug_event): Move from
windows-nat.c. No longer static.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.c (win32_kill, get_child_debug_event): Use
wait_for_debug_event.
This introduces a new "fetch_pending_stop" function and changes gdb to
use it. This function removes the first matching pending stop from
the list of such stops.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (get_windows_debug_event): Use
fetch_pending_stop.
* nat/windows-nat.h (fetch_pending_stop): Declare.
* nat/windows-nat.c (fetch_pending_stop): New function.
This adds a couple of functions to nat/windows-nat.c and changes gdb
and gdbserver to use them. One function checks the list of pending
stops for a match (not yet used by gdbserver, but will be in a
subsequent patch); and the other is a wrapper for ContinueDebugEvent
that always uses the last "real" stop event.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (windows_continue): Use matching_pending_stop and
continue_last_debug_event.
* nat/windows-nat.h (matching_pending_stop)
(continue_last_debug_event): Declare.
* nat/windows-nat.c (DEBUG_EVENTS): New define.
(matching_pending_stop, continue_last_debug_event): New
functions.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.c (child_continue): Call continue_last_debug_event.
Both gdb and gdbserver have a "handle_exception" function, the bulk of
which is shared between the two implementations. This patch arranges
for the entire thing to be moved into nat/windows-nat.c, with the
differences handled by callbacks. This patch introduces one more
callback to make this possible.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (MS_VC_EXCEPTION): Move to nat/windows-nat.c.
(handle_exception_result): Move to nat/windows-nat.h.
(DEBUG_EXCEPTION_SIMPLE): Remove.
(windows_nat::handle_ms_vc_exception): New function.
(handle_exception): Move to nat/windows-nat.c.
(get_windows_debug_event): Update.
(STATUS_WX86_BREAKPOINT, STATUS_WX86_SINGLE_STEP): Move to
nat/windows-nat.c.
* nat/windows-nat.h (handle_ms_vc_exception): Declare.
(handle_exception_result): Move from windows-nat.c.
(handle_exception): Declare.
* nat/windows-nat.c (MS_VC_EXCEPTION, handle_exception)
(STATUS_WX86_SINGLE_STEP, STATUS_WX86_BREAKPOINT): Move from
windows-nat.c.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.c (handle_exception): Remove.
(windows_nat::handle_ms_vc_exception): New function.
(get_child_debug_event): Add "continue_status" parameter.
Update.
(win32_wait): Update.
This changes nat/windows-nat.h to declare handle_load_dll and
handle_unload_dll. The embedding application is required to implement
these -- while the actual code was difficult to share due to some
other differences between the two programs, sharing the declaration
lets a subsequent patch share more code that uses these as callbacks.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (windows_nat::handle_load_dll)
(windows_nat::handle_unload_dll): Rename. No longer static.
* nat/windows-nat.h (handle_load_dll, handle_unload_dll):
Declare.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.c (windows_nat::handle_load_dll): Rename from
handle_load_dll. No longer static.
(windows_nat::handle_unload_dll): Rename from handle_unload_dll.
No longer static.
This changes gdbserver's implementation of handle_output_debug_string
to have the same calling convention as that of gdb. This allows for
sharing some more code in a subsequent patch.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (windows_nat::handle_output_debug_string):
Rename. No longer static.
* nat/windows-nat.h (handle_output_debug_string): Declare.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.c (handle_output_debug_string): Add parameter. Change
return type.
(win32_kill, get_child_debug_event): Update.
This moves get_image_name to nat/windows-nat.c so that it can be
shared between gdb and gdbserver.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (get_image_name): Move to nat/windows-nat.c.
(handle_load_dll): Update.
* nat/windows-nat.c (get_image_name): Move from windows-nat.c.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.c (get_image_name): Remove.
(handle_load_dll): Update.
This changes gdb and gdbserver to use the same calling convention for
the "thread_rec" helper function. Fully merging these is difficult
due to differences in how threads are managed by the enclosing
applications; but sharing a declaration makes it possible for future
shared code to call this method.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (enum thread_disposition_type): Move to
nat/windows-nat.h.
(windows_nat::thread_rec): Rename from thread_rec. No longer
static.
(windows_add_thread, windows_nat_target::fetch_registers)
(windows_nat_target::store_registers, handle_exception)
(windows_nat_target::resume, get_windows_debug_event)
(windows_nat_target::get_tib_address)
(windows_nat_target::thread_name)
(windows_nat_target::thread_alive): Update.
* nat/windows-nat.h (enum thread_disposition_type): Move from
windows-nat.c.
(thread_rec): Declare.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.c (windows_nat::thread_rec): Rename from thread_rec.
No longer static. Change parameters.
(child_add_thread, child_fetch_inferior_registers)
(child_store_inferior_registers, win32_resume)
(win32_get_tib_address): Update.
PR gdb/22992 concerns an assertion failure in gdb when debugging a
certain inferior:
int finish_step_over(execution_control_state*): Assertion `ecs->event_thread->control.trap_expected' failed.
Initially the investigation centered on the discovery that gdb was not
suspending other threads when attempting to single-step. This
oversight is corrected in this patch: now, when stepping a thread, gdb
will call SuspendThread on all other threads.
However, the bug persisted even after this change. In particular,
WaitForDebugEvent could see a stop for a thread that was ostensibly
suspended. Our theory of what is happening here is that there are
actually simultaneous breakpoint hits, and the Windows kernel queues
the events, causing the second stop to be reported on a suspended
thread.
In Windows 10 or later gdb could use the DBG_REPLY_LATER flag to
ContinueDebugEvent to request that such events be re-reported later.
However, relying on that did not seem advisable, so this patch instead
arranges to queue such "pending" stops, and then to report them later,
once the step has completed.
In the PR, Pedro pointed out that it's best in this scenario to
implement the stopped_by_sw_breakpoint method, so this patch does this
as well.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
PR gdb/22992
* windows-nat.c (current_event): Update comment.
(last_wait_event, desired_stop_thread_id): New globals.
(struct pending_stop): New.
(pending_stops): New global.
(windows_nat_target) <stopped_by_sw_breakpoint>
<supports_stopped_by_sw_breakpoint>: New methods.
(windows_fetch_one_register): Add assertions. Adjust PC.
(windows_continue): Handle pending stops. Suspend other threads
when stepping. Use last_wait_event
(wait_for_debug_event): New function.
(get_windows_debug_event): Use wait_for_debug_event. Handle
pending stops. Queue spurious stops.
(windows_nat_target::wait): Set stopped_at_software_breakpoint.
(windows_nat_target::kill): Use wait_for_debug_event.
* nat/windows-nat.h (struct windows_thread_info)
<stopped_at_software_breakpoint>: New field.
* nat/windows-nat.c (windows_thread_info::resume): Clear
stopped_at_software_breakpoint.
This adds "suspend" and "resume" methods to windows_thread_info, and
changes gdb and gdbserver to share this code.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (thread_rec): Use windows_thread_info::suspend.
(windows_continue): Use windows_continue::resume.
* nat/windows-nat.h (struct windows_thread_info) <suspend,
resume>: Declare new methods.
* nat/windows-nat.c: New file.
* configure.nat (NATDEPFILES): Add nat/windows-nat.o when needed.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.c (win32_require_context, suspend_one_thread): Use
windows_thread_info::suspend.
(continue_one_thread): Use windows_thread_info::resume.
* configure.srv (srv_tgtobj): Add windows-nat.o when needed.
This changes windows_thread_info::name to be a unique_xmalloc_ptr,
removing some manual memory management.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (handle_exception)
(windows_nat_target::thread_name): Update.
* nat/windows-nat.h (windows_thread_info): Remove destructor.
<name>: Now unique_xmalloc_ptr.
This changes a couple of fields of windows_thread_info to have type
"bool". It also updates the comment of another field, to clarify the
possible values it can hold.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (thread_rec)
(windows_nat_target::fetch_registers): Update.
* nat/windows-nat.h (struct windows_thread_info) <suspended>:
Update comment.
<debug_registers_changed, reload_context>: Now bool.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-i386-low.c (update_debug_registers)
(i386_prepare_to_resume, i386_thread_added): Update.
This adds a constructor, destructor, and member initializers to
windows_thread_info, and changes gdb and gdbserver to use new and
delete.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (windows_add_thread): Use new.
(windows_init_thread_list, windows_delete_thread): Use delete.
(get_windows_debug_event): Update.
* nat/windows-nat.h (struct windows_thread_info): Add constructor,
destructor, and initializers.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.c (child_add_thread): Use new.
(delete_thread_info): Use delete.
This introduces a new file, nat/windows-nat.h, which holds the
definition of windows_thread_info. This is now shared between gdb and
gdbserver.
Note that the two implementations different slightly. gdb had a
couple of fields ("name" and "reload_context") that gdbserver did not;
while gdbserver had one field ("base_context") that gdb did not, plus
better comments. The new file preserves all the fields, and the
comments.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (struct windows_thread_info): Remove.
* nat/windows-nat.h: New file.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.h (struct windows_thread_info): Remove.
I stumbled on this snippet in nat/gdb_ptrace.h:
/* Some systems, in particular DEC OSF/1, Digital Unix, Compaq Tru64
or whatever it's called these days, don't provide a prototype for
ptrace. Provide one to silence compiler warnings. */
#ifndef HAVE_DECL_PTRACE
extern PTRACE_TYPE_RET ptrace();
#endif
I believe this is unnecessary today and should be removed. First, the
comment only mentions OSes we don't support (and to be honest, I had
never even heard of).
But most importantly, in C++, a declaration with empty parenthesis
declares a function that accepts no arguments, unlike in C. So if this
declaration was really used, GDB wouldn't build, since all ptrace call
sites pass some arguments. Since we haven't heard anything about this
causing some build failures since we have transitioned to C++, I
conclude that it's not used.
This patch removes it as well as the corresponding configure check.
gdb/ChangeLog:
* ptrace.m4: Don't check for ptrace declaration.
* config.in: Re-generate.
* configure: Re-generate.
* nat/gdb_ptrace.h: Don't declare ptrace if HAVE_DECL_PTRACE is
not defined.
gdbserver/ChangeLog:
* config.in: Re-generate.
* configure: Re-generate.
gdbsupport/ChangeLog:
* config.in: Re-generate.
* configure: Re-generate.
I was doing some SVE tests on system QEMU and noticed quite a few failures
related to inferior function calls. Any attempt to do an inferior function
call would result in the following:
Unable to set VG register.: Success.
This happens because, after an inferior function call, GDB attempts to restore
the regcache state and updates the SVE register in order. Since the Z registers
show up before the VG register, VG is still INVALID by the time the first Z
register is being updated. So when executing the following code in
aarch64_sve_set_vq:
if (reg_buf->get_register_status (AARCH64_SVE_VG_REGNUM) != REG_VALID)
return false;
By returning false, we signal something is wrong, then we get to this:
/* First store vector length to the thread. This is done first to ensure the
ptrace buffers read from the kernel are the correct size. */
if (!aarch64_sve_set_vq (tid, regcache))
perror_with_name (_("Unable to set VG register."));
Ideally we'd always have a valid VG before attempting to set the Z registers,
but in this case the ordering of registers doesn't make that possible.
I considered reordering the registers to put VG before the Z registers, like
the DWARF numbering, but that would break backwards compatibility with
existing implementations. Also, the Z register numbering is pinned to the V
registers, and adding VG before Z would create a gap for non-SVE targets,
since we wouldn't be able to undefine VG for non-SVE targets.
As a compromise, it seems we can safely fetch the VG register value from
ptrace. The value in the kernel is likely the updated value anyway.
This patch fixed all the failures i saw in the testsuite and caused no further
regressions.
gdb/ChangeLog:
2020-03-19 Luis Machado <luis.machado@linaro.org>
* nat/aarch64-sve-linux-ptrace.c (aarch64_sve_set_vq): If vg is not
valid, fetch vg value from ptrace.
In preparation for adding the RISC-V gdbserver, this commit
restructures the API for looking up target descriptions.
The current API is riscv_create_target_description, which creates a
target description from a riscv_gdbarch_features, but also caches the
created target descriptions so that for a given features object we
always get back the same target description object. This is important
for GDB due to the way gdbarch objects are reused.
As the same target description is always returned to GDB, and can be
returned multiple times, it is returned as a const, however, the
current cache actually stores a non-const target description. This is
improved in this patch so that the cache holds a const target
description.
For gdbsever, this caching of the target descriptions is not needed,
the gdbserver looks up one target description to describe the target
it is actually running on and that is it. Further the gdbserver
actually needs to modify the target description that is looked up, so
for the gdbsever, returning a const target description is not
acceptable.
This commit aims to address this by creating two parallel target
description APIs, on is the old riscv_create_target_description,
however, this no longer performs any caching, and just creates a new
target description, and returns it as non-const.
The second API is riscv_lookup_target_description, this one performs
the caching, and calls riscv_create_target_description to create a
target description when needed.
In order to make sure the correct API is used in the correct place I
have guarded the code using the GDBSERVER define. For GDB the
riscv_create_target_description is static, and not generally usable
throughout GDB, only the lookup API is global. In gdbserver, the
lookup functions, and the cache are not defined or created at all,
only the riscv_create_target_description API is available.
There should be no user visible changes after this commit.
gdb/ChangeLog:
* arch/riscv.c (struct riscv_gdbarch_features_hasher): Only define
if GDBSERVER is not defined.
(riscv_tdesc_cache): Likewise, also store const target_desc.
(STATIC_IN_GDB): Define.
(riscv_create_target_description): Update declaration with
STATIC_IN_GDB.
(riscv_lookup_target_description): New function, only define if
GDBSERVER is not defined.
* arch/riscv.h (riscv_create_target_description): Declare only
when GDBSERVER is defined.
(riscv_lookup_target_description): New declaration when GDBSERVER
is not defined.
* nat/riscv-linux-tdesc.c (riscv_linux_read_description): Rename to...
(riscv_linux_read_features): ...this, and return
riscv_gdbarch_features instead of target_desc.
* nat/riscv-linux-tdesc.h: Include 'arch/riscv.h'.
(riscv_linux_read_description): Rename to...
(riscv_linux_read_features): ...this.
* riscv-linux-nat.c (riscv_linux_nat_target::read_description):
Update to use riscv_gdbarch_features and
riscv_lookup_target_description.
* riscv-tdep.c (riscv_find_default_target_description): Use
riscv_lookup_target_description instead of
riscv_create_target_description.
In preparation for RISC-V/Linux `gdbserver' support factor out parts of
native target description determination code that can be shared between
the programs.
gdb/
* nat/riscv-linux-tdesc.h: New file.
* nat/riscv-linux-tdesc.c: New file, taking code from...
* riscv-linux-nat.c (riscv_linux_nat_target::read_description):
... here.
* configure.nat <linux> <riscv*>: Add nat/riscv-linux-tdesc.o to
NATDEPFILES.
The darwin-nat.c file doesn't build since the multi-target changes
(5b6d1e4f, "Multi-target support"). This patch makes it build. I have
access to a macOS vm, so I am able to build it, but I wasn't able to
successfully codesign it and try to actually debug something, so I don't
know if it works. I don't have much more time to put on this to figure
it out, so I thought I'd sent the patch anyway, as it's at least a step
in the right direction.
The bulk of the patch is to change a bunch of functions to be methods of
the darwin_nat_target object, so that this can pass `this` to
find_inferior_ptid and other functions that now require a
process_stratum_target pointer.
The darwin_ptrace_him function (renamed to darwin_nat_target::ptrace_him
in this patch) is passed to fork_inferior as the `init_trace_fun`
parameter. Since the method can't be passed as a plain function pointer
(we need the `this` pointer), I changed the `init_trace_fun` parameter
of fork_inferior to be a gdb::function_view, so we can pass a lambda and
capture `this`.
The changes in darwin-nat.h are only to move definition higher in the
file, so that forward declarations are not needed.
gdb/ChangeLog:
* darwin-nat.h (struct darwin_exception_msg, enum
darwin_msg_state, struct darwin_thread_info, darwin_thread_t):
Move up.
(class darwin_nat_target) <wait_1, check_new_threads,
decode_exception_message, decode_message, stop_inferior,
init_thread_list, ptrace_him, cancel_breakpoint>: Declare.
* darwin-nat.c (darwin_check_new_threads): Rename to...
(darwin_nat_target::check_new_threads): ... this.
(darwin_suspend_inferior_it): Remove.
(darwin_decode_exception_message): Rename to...
(darwin_nat_target::decode_exception_message): ... this.
(darwin_nat_target::resume): Pass target to find_inferior_ptid.
(darwin_decode_message): Rename to...
(darwin_nat_target::decode_message): ... this.
(cancel_breakpoint): Rename to...
(darwin_nat_target::cancel_breakpoint): ... this.
(darwin_wait): Rename to...
(darwin_nat_target::wait_1): ... this. Use range-based for loop
instead of iterate_over_inferiors.
(darwin_nat_target::wait): Call wait_1 instead of darwin_wait.
(darwin_stop_inferior): Rename to...
(darwin_nat_target::stop_inferior): ... this.
(darwin_nat_target::kill): Call wait_1 instead of darwin_wait.
(darwin_init_thread_list): Rename to...
(darwin_nat_target::init_thread_list): ... this.
(darwin_ptrace_him): Rename to...
(darwin_nat_target::ptrace_him): ... this.
(darwin_nat_target::create_inferior): Pass lambda function to
fork_inferior.
(darwin_nat_target::detach): Call stop_inferior instead of
darwin_stop_inferior.
* fork-inferior.h (fork_inferior): Change init_trace_fun
parameter to gdb::function_view.
* fork-inferior.c (fork_inferior): Likewise.
This removes the use of <config.h> from the files in gdb/nat/.
gdb/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* nat/linux-btrace.c: Don't include <config.h>.
* nat/linux-ptrace.c: Don't include <config.h>.
* nat/x86-linux-dregs.c: Don't include <config.h>.
Change-Id: Ie8c734c54ada848aa020c77ec727704d367eff81
This patch moves the gdbsupport directory to the top level. This is
the next step in the ongoing project to move gdbserver to the top
level.
The bulk of this patch was created by "git mv gdb/gdbsupport gdbsupport".
This patch then adds a build system to gdbsupport and wires it into
the top level. Then it changes gdb to use the top-level build.
gdbserver, on the other hand, is not yet changed. It still does its
own build of gdbsupport.
ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* src-release.sh (GDB_SUPPORT_DIRS): Add gdbsupport.
* MAINTAINERS: Add gdbsupport.
* configure: Rebuild.
* configure.ac (configdirs): Add gdbsupport.
* gdbsupport: New directory, move from gdb/gdbsupport.
* Makefile.def (host_modules, dependencies): Add gnulib.
* Makefile.in: Rebuild.
gdb/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* nat/x86-linux-dregs.c: Include configh.h.
* nat/linux-ptrace.c: Include configh.h.
* nat/linux-btrace.c: Include configh.h.
* defs.h: Include config.h, bfd.h.
* configure.ac: Don't source common.host.
(CONFIG_OBS, CONFIG_SRCS): Remove gdbsupport files.
* configure: Rebuild.
* acinclude.m4: Update path.
* Makefile.in (SUPPORT, LIBSUPPORT, INCSUPPORT): New variables.
(CONFIG_SRC_SUBDIR): Remove gdbsupport.
(INTERNAL_CFLAGS_BASE): Add INCSUPPORT.
(CLIBS): Add LIBSUPPORT.
(CDEPS): Likewise.
(COMMON_SFILES): Remove gdbsupport files.
(HFILES_NO_SRCDIR): Likewise.
(stamp-version): Update path to create-version.sh.
(ALLDEPFILES): Remove gdbsupport files.
gdb/gdbserver/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* server.h: Include config.h.
* gdbreplay.c: Include config.h.
* configure: Rebuild.
* configure.ac: Don't source common.host.
* acinclude.m4: Update path.
* Makefile.in (INCSUPPORT): New variable.
(INCLUDE_CFLAGS): Add INCSUPPORT.
(SFILES): Update paths.
(version-generated.c): Update path to create-version.sh.
(gdbsupport/%-ipa.o, gdbsupport/%.o): Update paths.
gdbsupport/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* common-defs.h: Add GDBSERVER case. Update includes.
* acinclude.m4, aclocal.m4, config.in, configure, configure.ac,
Makefile.am, Makefile.in, README: New files.
* Moved from ../gdb/gdbsupport/
Change-Id: I07632e7798635c1bab389bf885971e584fb4bb78
This commit adds multi-target support to GDB. What this means is that
with this commit, GDB can now be connected to different targets at the
same time. E.g., you can debug a live native process and a core dump
at the same time, connect to multiple gdbservers, etc.
Actually, the word "target" is overloaded in gdb. We already have a
target stack, with pushes several target_ops instances on top of one
another. We also have "info target" already, which means something
completely different to what this patch does.
So from here on, I'll be using the "target connections" term, to mean
an open process_stratum target, pushed on a target stack. This patch
makes gdb have multiple target stacks, and multiple process_stratum
targets open simultaneously. The user-visible changes / commands will
also use this terminology, but of course it's all open to debate.
User-interface-wise, not that much changes. The main difference is
that each inferior may have its own target connection.
A target connection (e.g., a target extended-remote connection) may
support debugging multiple processes, just as before.
Say you're debugging against gdbserver in extended-remote mode, and
you do "add-inferior" to prepare to spawn a new process, like:
(gdb) target extended-remote :9999
...
(gdb) start
...
(gdb) add-inferior
Added inferior 2
(gdb) inferior 2
[Switching to inferior 2 [<null>] (<noexec>)]
(gdb) file a.out
...
(gdb) start
...
At this point, you have two inferiors connected to the same gdbserver.
With this commit, GDB will maintain a target stack per inferior,
instead of a global target stack.
To preserve the behavior above, by default, "add-inferior" makes the
new inferior inherit a copy of the target stack of the current
inferior. Same across a fork - the child inherits a copy of the
target stack of the parent. While the target stacks are copied, the
targets themselves are not. Instead, target_ops is made a
refcounted_object, which means that target_ops instances are
refcounted, which each inferior counting for a reference.
What if you want to create an inferior and connect it to some _other_
target? For that, this commit introduces a new "add-inferior
-no-connection" option that makes the new inferior not share the
current inferior's target. So you could do:
(gdb) target extended-remote :9999
Remote debugging using :9999
...
(gdb) add-inferior -no-connection
[New inferior 2]
Added inferior 2
(gdb) inferior 2
[Switching to inferior 2 [<null>] (<noexec>)]
(gdb) info inferiors
Num Description Executable
1 process 18401 target:/home/pedro/tmp/main
* 2 <null>
(gdb) tar extended-remote :10000
Remote debugging using :10000
...
(gdb) info inferiors
Num Description Executable
1 process 18401 target:/home/pedro/tmp/main
* 2 process 18450 target:/home/pedro/tmp/main
(gdb)
A following patch will extended "info inferiors" to include a column
indicating which connection an inferior is bound to, along with a
couple other UI tweaks.
Other than that, debugging is the same as before. Users interact with
inferiors and threads as before. The only difference is that
inferiors may be bound to processes running in different machines.
That's pretty much all there is to it in terms of noticeable UI
changes.
On to implementation.
Since we can be connected to different systems at the same time, a
ptid_t is no longer a unique identifier. Instead a thread can be
identified by a pair of ptid_t and 'process_stratum_target *', the
later being the instance of the process_stratum target that owns the
process/thread. Note that process_stratum_target inherits from
target_ops, and all process_stratum targets inherit from
process_stratum_target. In earlier patches, many places in gdb were
converted to refer to threads by thread_info pointer instead of
ptid_t, but there are still places in gdb where we start with a
pid/tid and need to find the corresponding inferior or thread_info
objects. So you'll see in the patch many places adding a
process_stratum_target parameter to functions that used to take only a
ptid_t.
Since each inferior has its own target stack now, we can always find
the process_stratum target for an inferior. That is done via a
inf->process_target() convenience method.
Since each inferior has its own target stack, we need to handle the
"beneath" calls when servicing target calls. The solution I settled
with is just to make sure to switch the current inferior to the
inferior you want before making a target call. Not relying on global
context is just not feasible in current GDB. Fortunately, there
aren't that many places that need to do that, because generally most
code that calls target methods already has the current context
pointing to the right inferior/thread. Note, to emphasize -- there's
no method to "switch to this target stack". Instead, you switch the
current inferior, and that implicitly switches the target stack.
In some spots, we need to iterate over all inferiors so that we reach
all target stacks.
Native targets are still singletons. There's always only a single
instance of such targets.
Remote targets however, we'll have one instance per remote connection.
The exec target is still a singleton. There's only one instance. I
did not see the point of instanciating more than one exec_target
object.
After vfork, we need to make sure to push the exec target on the new
inferior. See exec_on_vfork.
For type safety, functions that need a {target, ptid} pair to identify
a thread, take a process_stratum_target pointer for target parameter
instead of target_ops *. Some shared code in gdb/nat/ also need to
gain a target pointer parameter. This poses an issue, since gdbserver
doesn't have process_stratum_target, only target_ops. To fix this,
this commit renames gdbserver's target_ops to process_stratum_target.
I think this makes sense. There's no concept of target stack in
gdbserver, and gdbserver's target_ops really implements a
process_stratum-like target.
The thread and inferior iterator functions also gain
process_stratum_target parameters. These are used to be able to
iterate over threads and inferiors of a given target. Following usual
conventions, if the target pointer is null, then we iterate over
threads and inferiors of all targets.
I tried converting "add-inferior" to the gdb::option framework, as a
preparatory patch, but that stumbled on the fact that gdb::option does
not support file options yet, for "add-inferior -exec". I have a WIP
patchset that adds that, but it's not a trivial patch, mainly due to
need to integrate readline's filename completion, so I deferred that
to some other time.
In infrun.c/infcmd.c, the main change is that we need to poll events
out of all targets. See do_target_wait. Right after collecting an
event, we switch the current inferior to an inferior bound to the
target that reported the event, so that target methods can be used
while handling the event. This makes most of the code transparent to
multi-targets. See fetch_inferior_event.
infrun.c:stop_all_threads is interesting -- in this function we need
to stop all threads of all targets. What the function does is send an
asynchronous stop request to all threads, and then synchronously waits
for events, with target_wait, rinse repeat, until all it finds are
stopped threads. Now that we have multiple targets, it's not
efficient to synchronously block in target_wait waiting for events out
of one target. Instead, we implement a mini event loop, with
interruptible_select, select'ing on one file descriptor per target.
For this to work, we need to be able to ask the target for a waitable
file descriptor. Such file descriptors already exist, they are the
descriptors registered in the main event loop with add_file_handler,
inside the target_async implementations. This commit adds a new
target_async_wait_fd target method that just returns the file
descriptor in question. See wait_one / stop_all_threads in infrun.c.
The 'threads_executing' global is made a per-target variable. Since
it is only relevant to process_stratum_target targets, this is where
it is put, instead of in target_ops.
You'll notice that remote.c includes some FIXME notes. These refer to
the fact that the global arrays that hold data for the remote packets
supported are still globals. For example, if we connect to two
different servers/stubs, then each might support different remote
protocol features. They might even be different architectures, like
e.g., one ARM baremetal stub, and a x86 gdbserver, to debug a
host/controller scenario as a single program. That isn't going to
work correctly today, because of said globals. I'm leaving fixing
that for another pass, since it does not appear to be trivial, and I'd
rather land the base work first. It's already useful to be able to
debug multiple instances of the same server (e.g., a distributed
cluster, where you have full control over the servers installed), so I
think as is it's already reasonable incremental progress.
Current limitations:
- You can only resume more that one target at the same time if all
targets support asynchronous debugging, and support non-stop mode.
It should be possible to support mixed all-stop + non-stop
backends, but that is left for another time. This means that
currently in order to do multi-target with gdbserver you need to
issue "maint set target-non-stop on". I would like to make that
mode be the default, but we're not there yet. Note that I'm
talking about how the target backend works, only. User-visible
all-stop mode works just fine.
- As explained above, connecting to different remote servers at the
same time is likely to produce bad results if they don't support the
exact set of RSP features.
FreeBSD updates courtesy of John Baldwin.
gdb/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
John Baldwin <jhb@FreeBSD.org>
* aarch64-linux-nat.c
(aarch64_linux_nat_target::thread_architecture): Adjust.
* ada-tasks.c (print_ada_task_info): Adjust find_thread_ptid call.
(task_command_1): Likewise.
* aix-thread.c (sync_threadlists, aix_thread_target::resume)
(aix_thread_target::wait, aix_thread_target::fetch_registers)
(aix_thread_target::store_registers)
(aix_thread_target::thread_alive): Adjust.
* amd64-fbsd-tdep.c: Include "inferior.h".
(amd64fbsd_get_thread_local_address): Pass down target.
* amd64-linux-nat.c (ps_get_thread_area): Use ps_prochandle
thread's gdbarch instead of target_gdbarch.
* break-catch-sig.c (signal_catchpoint_print_it): Adjust call to
get_last_target_status.
* break-catch-syscall.c (print_it_catch_syscall): Likewise.
* breakpoint.c (breakpoints_should_be_inserted_now): Consider all
inferiors.
(update_inserted_breakpoint_locations): Skip if inferiors with no
execution.
(update_global_location_list): When handling moribund locations,
find representative inferior for location's pspace, and use thread
count of its process_stratum target.
* bsd-kvm.c (bsd_kvm_target_open): Pass target down.
* bsd-uthread.c (bsd_uthread_target::wait): Use
as_process_stratum_target and adjust thread_change_ptid and
add_thread calls.
(bsd_uthread_target::update_thread_list): Use
as_process_stratum_target and adjust find_thread_ptid,
thread_change_ptid and add_thread calls.
* btrace.c (maint_btrace_packet_history_cmd): Adjust
find_thread_ptid call.
* corelow.c (add_to_thread_list): Adjust add_thread call.
(core_target_open): Adjust add_thread_silent and thread_count
calls.
(core_target::pid_to_str): Adjust find_inferior_ptid call.
* ctf.c (ctf_target_open): Adjust add_thread_silent call.
* event-top.c (async_disconnect): Pop targets from all inferiors.
* exec.c (add_target_sections): Push exec target on all inferiors
sharing the program space.
(remove_target_sections): Remove the exec target from all
inferiors sharing the program space.
(exec_on_vfork): New.
* exec.h (exec_on_vfork): Declare.
* fbsd-nat.c (fbsd_add_threads): Add fbsd_nat_target parameter.
Pass it down.
(fbsd_nat_target::update_thread_list): Adjust.
(fbsd_nat_target::resume): Adjust.
(fbsd_handle_debug_trap): Add fbsd_nat_target parameter. Pass it
down.
(fbsd_nat_target::wait, fbsd_nat_target::post_attach): Adjust.
* fbsd-tdep.c (fbsd_corefile_thread): Adjust
get_thread_arch_regcache call.
* fork-child.c (gdb_startup_inferior): Pass target down to
startup_inferior and set_executing.
* gdbthread.h (struct process_stratum_target): Forward declare.
(add_thread, add_thread_silent, add_thread_with_info)
(in_thread_list): Add process_stratum_target parameter.
(find_thread_ptid(inferior*, ptid_t)): New overload.
(find_thread_ptid, thread_change_ptid): Add process_stratum_target
parameter.
(all_threads()): Delete overload.
(all_threads, all_non_exited_threads): Add process_stratum_target
parameter.
(all_threads_safe): Use brace initialization.
(thread_count): Add process_stratum_target parameter.
(set_resumed, set_running, set_stop_requested, set_executing)
(threads_are_executing, finish_thread_state): Add
process_stratum_target parameter.
(switch_to_thread): Use is_current_thread.
* i386-fbsd-tdep.c: Include "inferior.h".
(i386fbsd_get_thread_local_address): Pass down target.
* i386-linux-nat.c (i386_linux_nat_target::low_resume): Adjust.
* inf-child.c (inf_child_target::maybe_unpush_target): Remove
have_inferiors check.
* inf-ptrace.c (inf_ptrace_target::create_inferior)
(inf_ptrace_target::attach): Adjust.
* infcall.c (run_inferior_call): Adjust.
* infcmd.c (run_command_1): Pass target to
scoped_finish_thread_state.
(proceed_thread_callback): Skip inferiors with no execution.
(continue_command): Rename 'all_threads' local to avoid hiding
'all_threads' function. Adjust get_last_target_status call.
(prepare_one_step): Adjust set_running call.
(signal_command): Use user_visible_resume_target. Compare thread
pointers instead of inferior_ptid.
(info_program_command): Adjust to pass down target.
(attach_command): Mark target's 'thread_executing' flag.
(stop_current_target_threads_ns): New, factored out from ...
(interrupt_target_1): ... this. Switch inferior before making
target calls.
* inferior-iter.h
(struct all_inferiors_iterator, struct all_inferiors_range)
(struct all_inferiors_safe_range)
(struct all_non_exited_inferiors_range): Filter on
process_stratum_target too. Remove explicit.
* inferior.c (inferior::inferior): Push dummy target on target
stack.
(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors):
Add process_stratum_target parameter, and pass it down.
(have_live_inferiors): Adjust.
(switch_to_inferior_and_push_target): New.
(add_inferior_command, clone_inferior_command): Handle
"-no-connection" parameter. Use
switch_to_inferior_and_push_target.
(_initialize_inferior): Mention "-no-connection" option in
the help of "add-inferior" and "clone-inferior" commands.
* inferior.h: Include "process-stratum-target.h".
(interrupt_target_1): Use bool.
(struct inferior) <push_target, unpush_target, target_is_pushed,
find_target_beneath, top_target, process_target, target_at,
m_stack>: New.
(discard_all_inferiors): Delete.
(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors)
(all_inferiors, all_non_exited_inferiors): Add
process_stratum_target parameter.
* infrun.c: Include "gdb_select.h" and <unordered_map>.
(target_last_proc_target): New global.
(follow_fork_inferior): Push target on new inferior. Pass target
to add_thread_silent. Call exec_on_vfork. Handle target's
reference count.
(follow_fork): Adjust get_last_target_status call. Also consider
target.
(follow_exec): Push target on new inferior.
(struct execution_control_state) <target>: New field.
(user_visible_resume_target): New.
(do_target_resume): Call target_async.
(resume_1): Set target's threads_executing flag. Consider resume
target.
(commit_resume_all_targets): New.
(proceed): Also consider resume target. Skip threads of inferiors
with no execution. Commit resumtion in all targets.
(start_remote): Pass current inferior to wait_for_inferior.
(infrun_thread_stop_requested): Consider target as well. Pass
thread_info pointer to clear_inline_frame_state instead of ptid.
(infrun_thread_thread_exit): Consider target as well.
(random_pending_event_thread): New inferior parameter. Use it.
(do_target_wait): Rename to ...
(do_target_wait_1): ... this. Add inferior parameter, and pass it
down.
(threads_are_resumed_pending_p, do_target_wait): New.
(prepare_for_detach): Adjust calls.
(wait_for_inferior): New inferior parameter. Handle it. Use
do_target_wait_1 instead of do_target_wait.
(fetch_inferior_event): Adjust. Switch to representative
inferior. Pass target down.
(set_last_target_status): Add process_stratum_target parameter.
Save target in global.
(get_last_target_status): Add process_stratum_target parameter and
handle it.
(nullify_last_target_wait_ptid): Clear 'target_last_proc_target'.
(context_switch): Check inferior_ptid == null_ptid before calling
inferior_thread().
(get_inferior_stop_soon): Pass down target.
(wait_one): Rename to ...
(poll_one_curr_target): ... this.
(struct wait_one_event): New.
(wait_one): New.
(stop_all_threads): Adjust.
(handle_no_resumed, handle_inferior_event): Adjust to consider the
event's target.
(switch_back_to_stepped_thread): Also consider target.
(print_stop_event): Update.
(normal_stop): Update. Also consider the resume target.
* infrun.h (wait_for_inferior): Remove declaration.
(user_visible_resume_target): New declaration.
(get_last_target_status, set_last_target_status): New
process_stratum_target parameter.
* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
process_stratum_target parameter, and use it.
(clear_inline_frame_state (thread_info*)): New.
* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
process_stratum_target parameter.
(clear_inline_frame_state (thread_info*)): Declare.
* linux-fork.c (delete_checkpoint_command): Pass target down to
find_thread_ptid.
(checkpoint_command): Adjust.
* linux-nat.c (linux_nat_target::follow_fork): Switch to thread
instead of just tweaking inferior_ptid.
(linux_nat_switch_fork): Pass target down to thread_change_ptid.
(exit_lwp): Pass target down to find_thread_ptid.
(attach_proc_task_lwp_callback): Pass target down to
add_thread/set_running/set_executing.
(linux_nat_target::attach): Pass target down to
thread_change_ptid.
(get_detach_signal): Pass target down to find_thread_ptid.
Consider last target status's target.
(linux_resume_one_lwp_throw, resume_lwp)
(linux_handle_syscall_trap, linux_handle_extended_wait, wait_lwp)
(stop_wait_callback, save_stop_reason, linux_nat_filter_event)
(linux_nat_wait_1, resume_stopped_resumed_lwps): Pass target down.
(linux_nat_target::async_wait_fd): New.
(linux_nat_stop_lwp, linux_nat_target::thread_address_space): Pass
target down.
* linux-nat.h (linux_nat_target::async_wait_fd): Declare.
* linux-tdep.c (get_thread_arch_regcache): Pass target down.
* linux-thread-db.c (struct thread_db_info::process_target): New
field.
(add_thread_db_info): Save target.
(get_thread_db_info): New process_stratum_target parameter. Also
match target.
(delete_thread_db_info): New process_stratum_target parameter.
Also match target.
(thread_from_lwp): Adjust to pass down target.
(thread_db_notice_clone): Pass down target.
(check_thread_db_callback): Pass down target.
(try_thread_db_load_1): Always push the thread_db target.
(try_thread_db_load, record_thread): Pass target down.
(thread_db_target::detach): Pass target down. Always unpush the
thread_db target.
(thread_db_target::wait, thread_db_target::mourn_inferior): Pass
target down. Always unpush the thread_db target.
(find_new_threads_callback, thread_db_find_new_threads_2)
(thread_db_target::update_thread_list): Pass target down.
(thread_db_target::pid_to_str): Pass current inferior down.
(thread_db_target::get_thread_local_address): Pass target down.
(thread_db_target::resume, maintenance_check_libthread_db): Pass
target down.
* nto-procfs.c (nto_procfs_target::update_thread_list): Adjust.
* procfs.c (procfs_target::procfs_init_inferior): Declare.
(proc_set_current_signal, do_attach, procfs_target::wait): Adjust.
(procfs_init_inferior): Rename to ...
(procfs_target::procfs_init_inferior): ... this and adjust.
(procfs_target::create_inferior, procfs_notice_thread)
(procfs_do_thread_registers): Adjust.
* ppc-fbsd-tdep.c: Include "inferior.h".
(ppcfbsd_get_thread_local_address): Pass down target.
* proc-service.c (ps_xfer_memory): Switch current inferior and
program space as well.
(get_ps_regcache): Pass target down.
* process-stratum-target.c
(process_stratum_target::thread_address_space)
(process_stratum_target::thread_architecture): Pass target down.
* process-stratum-target.h
(process_stratum_target::threads_executing): New field.
(as_process_stratum_target): New.
* ravenscar-thread.c
(ravenscar_thread_target::update_inferior_ptid): Pass target down.
(ravenscar_thread_target::wait, ravenscar_add_thread): Pass target
down.
* record-btrace.c (record_btrace_target::info_record): Adjust.
(record_btrace_target::record_method)
(record_btrace_target::record_is_replaying)
(record_btrace_target::fetch_registers)
(get_thread_current_frame_id, record_btrace_target::resume)
(record_btrace_target::wait, record_btrace_target::stop): Pass
target down.
* record-full.c (record_full_wait_1): Switch to event thread.
Pass target down.
* regcache.c (regcache::regcache)
(get_thread_arch_aspace_regcache, get_thread_arch_regcache): Add
process_stratum_target parameter and handle it.
(current_thread_target): New global.
(get_thread_regcache): Add process_stratum_target parameter and
handle it. Switch inferior before calling target method.
(get_thread_regcache): Pass target down.
(get_thread_regcache_for_ptid): Pass target down.
(registers_changed_ptid): Add process_stratum_target parameter and
handle it.
(registers_changed_thread, registers_changed): Pass target down.
(test_get_thread_arch_aspace_regcache): New.
(current_regcache_test): Define a couple local test_target_ops
instances and use them for testing.
(readwrite_regcache): Pass process_stratum_target parameter.
(cooked_read_test, cooked_write_test): Pass mock_target down.
* regcache.h (get_thread_regcache, get_thread_arch_regcache)
(get_thread_arch_aspace_regcache): Add process_stratum_target
parameter.
(regcache::target): New method.
(regcache::regcache, regcache::get_thread_arch_aspace_regcache)
(regcache::registers_changed_ptid): Add process_stratum_target
parameter.
(regcache::m_target): New field.
(registers_changed_ptid): Add process_stratum_target parameter.
* remote.c (remote_state::supports_vCont_probed): New field.
(remote_target::async_wait_fd): New method.
(remote_unpush_and_throw): Add remote_target parameter.
(get_current_remote_target): Adjust.
(remote_target::remote_add_inferior): Push target.
(remote_target::remote_add_thread)
(remote_target::remote_notice_new_inferior)
(get_remote_thread_info): Pass target down.
(remote_target::update_thread_list): Skip threads of inferiors
bound to other targets. (remote_target::close): Don't discard
inferiors. (remote_target::add_current_inferior_and_thread)
(remote_target::process_initial_stop_replies)
(remote_target::start_remote)
(remote_target::remote_serial_quit_handler): Pass down target.
(remote_target::remote_unpush_target): New remote_target
parameter. Unpush the target from all inferiors.
(remote_target::remote_unpush_and_throw): New remote_target
parameter. Pass it down.
(remote_target::open_1): Check whether the current inferior has
execution instead of checking whether any inferior is live. Pass
target down.
(remote_target::remote_detach_1): Pass down target. Use
remote_unpush_target.
(extended_remote_target::attach): Pass down target.
(remote_target::remote_vcont_probe): Set supports_vCont_probed.
(remote_target::append_resumption): Pass down target.
(remote_target::append_pending_thread_resumptions)
(remote_target::remote_resume_with_hc, remote_target::resume)
(remote_target::commit_resume): Pass down target.
(remote_target::remote_stop_ns): Check supports_vCont_probed.
(remote_target::interrupt_query)
(remote_target::remove_new_fork_children)
(remote_target::check_pending_events_prevent_wildcard_vcont)
(remote_target::remote_parse_stop_reply)
(remote_target::process_stop_reply): Pass down target.
(first_remote_resumed_thread): New remote_target parameter. Pass
it down.
(remote_target::wait_as): Pass down target.
(unpush_and_perror): New remote_target parameter. Pass it down.
(remote_target::readchar, remote_target::remote_serial_write)
(remote_target::getpkt_or_notif_sane_1)
(remote_target::kill_new_fork_children, remote_target::kill): Pass
down target.
(remote_target::mourn_inferior): Pass down target. Use
remote_unpush_target.
(remote_target::core_of_thread)
(remote_target::remote_btrace_maybe_reopen): Pass down target.
(remote_target::pid_to_exec_file)
(remote_target::thread_handle_to_thread_info): Pass down target.
(remote_target::async_wait_fd): New.
* riscv-fbsd-tdep.c: Include "inferior.h".
(riscv_fbsd_get_thread_local_address): Pass down target.
* sol2-tdep.c (sol2_core_pid_to_str): Pass down target.
* sol-thread.c (sol_thread_target::wait, ps_lgetregs, ps_lsetregs)
(ps_lgetfpregs, ps_lsetfpregs, sol_update_thread_list_callback):
Adjust.
* solib-spu.c (spu_skip_standalone_loader): Pass down target.
* solib-svr4.c (enable_break): Pass down target.
* spu-multiarch.c (parse_spufs_run): Pass down target.
* spu-tdep.c (spu2ppu_sniffer): Pass down target.
* target-delegates.c: Regenerate.
* target.c (g_target_stack): Delete.
(current_top_target): Return the current inferior's top target.
(target_has_execution_1): Refer to the passed-in inferior's top
target.
(target_supports_terminal_ours): Check whether the initial
inferior was already created.
(decref_target): New.
(target_stack::push): Incref/decref the target.
(push_target, push_target, unpush_target): Adjust.
(target_stack::unpush): Defref target.
(target_is_pushed): Return bool. Adjust to refer to the current
inferior's target stack.
(dispose_inferior): Delete, and inline parts ...
(target_preopen): ... here. Only dispose of the current inferior.
(target_detach): Hold strong target reference while detaching.
Pass target down.
(target_thread_name): Add assertion.
(target_resume): Pass down target.
(target_ops::beneath, find_target_at): Adjust to refer to the
current inferior's target stack.
(get_dummy_target): New.
(target_pass_ctrlc): Pass the Ctrl-C to the first inferior that
has a thread running.
(initialize_targets): Rename to ...
(_initialize_target): ... this.
* target.h: Include "gdbsupport/refcounted-object.h".
(struct target_ops): Inherit refcounted_object.
(target_ops::shortname, target_ops::longname): Make const.
(target_ops::async_wait_fd): New method.
(decref_target): Declare.
(struct target_ops_ref_policy): New.
(target_ops_ref): New typedef.
(get_dummy_target): Declare function.
(target_is_pushed): Return bool.
* thread-iter.c (all_matching_threads_iterator::m_inf_matches)
(all_matching_threads_iterator::all_matching_threads_iterator):
Handle filter target.
* thread-iter.h (struct all_matching_threads_iterator, struct
all_matching_threads_range, class all_non_exited_threads_range):
Filter by target too. Remove explicit.
* thread.c (threads_executing): Delete.
(inferior_thread): Pass down current inferior.
(clear_thread_inferior_resources): Pass down thread pointer
instead of ptid_t.
(add_thread_silent, add_thread_with_info, add_thread): Add
process_stratum_target parameter. Use it for thread and inferior
searches.
(is_current_thread): New.
(thread_info::deletable): Use it.
(find_thread_ptid, thread_count, in_thread_list)
(thread_change_ptid, set_resumed, set_running): New
process_stratum_target parameter. Pass it down.
(set_executing): New process_stratum_target parameter. Pass it
down. Adjust reference to 'threads_executing'.
(threads_are_executing): New process_stratum_target parameter.
Adjust reference to 'threads_executing'.
(set_stop_requested, finish_thread_state): New
process_stratum_target parameter. Pass it down.
(switch_to_thread): Also match inferior.
(switch_to_thread): New process_stratum_target parameter. Pass it
down.
(update_threads_executing): Reimplement.
* top.c (quit_force): Pop targets from all inferior.
(gdb_init): Don't call initialize_targets.
* windows-nat.c (windows_nat_target) <get_windows_debug_event>:
Declare.
(windows_add_thread, windows_delete_thread): Adjust.
(get_windows_debug_event): Rename to ...
(windows_nat_target::get_windows_debug_event): ... this. Adjust.
* tracefile-tfile.c (tfile_target_open): Pass down target.
* gdbsupport/common-gdbthread.h (struct process_stratum_target):
Forward declare.
(switch_to_thread): Add process_stratum_target parameter.
* mi/mi-interp.c (mi_on_resume_1): Add process_stratum_target
parameter. Use it.
(mi_on_resume): Pass target down.
* nat/fork-inferior.c (startup_inferior): Add
process_stratum_target parameter. Pass it down.
* nat/fork-inferior.h (startup_inferior): Add
process_stratum_target parameter.
* python/py-threadevent.c (py_get_event_thread): Pass target down.
gdb/gdbserver/ChangeLog:
2020-01-10 Pedro Alves <palves@redhat.com>
* fork-child.c (post_fork_inferior): Pass target down to
startup_inferior.
* inferiors.c (switch_to_thread): Add process_stratum_target
parameter.
* lynx-low.c (lynx_target_ops): Now a process_stratum_target.
* nto-low.c (nto_target_ops): Now a process_stratum_target.
* linux-low.c (linux_target_ops): Now a process_stratum_target.
* remote-utils.c (prepare_resume_reply): Pass the target to
switch_to_thread.
* target.c (the_target): Now a process_stratum_target.
(done_accessing_memory): Pass the target to switch_to_thread.
(set_target_ops): Ajust to use process_stratum_target.
* target.h (struct target_ops): Rename to ...
(struct process_stratum_target): ... this.
(the_target, set_target_ops): Adjust.
(prepare_to_access_memory): Adjust comment.
* win32-low.c (child_xfer_memory): Adjust to use
process_stratum_target.
(win32_target_ops): Now a process_stratum_target.
To make these calls threadsafe. localtime_r is provided by gnulib if
necessary, and for ctime_r we can just use it because it is in a linux-
specific file.
gdb/ChangeLog:
2019-11-15 Christian Biesinger <cbiesinger@google.com>
* maint.c (scoped_command_stats::print_time): Use localtime_r
instead of localtime (provided through gnulib if necessary).
* nat/linux-osdata.c (time_from_time_t): Use ctime_r instead
of ctime.
Change-Id: I329bbdc39d5b576f51859ba00f1617e024c30cbd
Improves threadsafety. This will be important when the patch series at
https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/176
lands.
gdb/ChangeLog:
2019-11-06 Christian Biesinger <cbiesinger@google.com>
* linux-tdep.c (linux_info_proc): Use strtok_r instead of strtok.
* mi/mi-main.c (output_cores): Likewise.
* nat/linux-osdata.c (linux_xfer_osdata_cpus): Likewise.
(linux_xfer_osdata_modules): Likewise.
* remote.c (register_remote_support_xml): Likewise.
* sparc64-tdep.c (adi_is_addr_mapped): Likewise.
* xml-syscall.c (syscall_create_syscall_desc): Likewise.
gdb/gdbserver/ChangeLog:
2019-11-06 Christian Biesinger <cbiesinger@google.com>
* linux-x86-low.c (x86_linux_process_qsupported): Use strtok_r
instead of strtok.
* server.c (handle_query): Likewise.
(captured_main): Likewise.
Change-Id: Ief6138965a24398e5fc064598cd8f2abd3b5047c
In the following 3 commits:
commit df07e2c772
Date: Wed Sep 25 16:10:50 2019 +0100
gdb: Remove a use of VEC from dwarf2read.{c,h}
commit 554ac434b0
Date: Thu Sep 19 13:17:59 2019 -0400
gdb: Change a VEC to std::vector in btrace.{c,h}
commit 46f29a9a26
Date: Mon Sep 16 09:12:27 2019 -0400
gdb: Remove a VEC from gdbsupport/btrace-common.h
I incorrectly wrote 'std::vector <...>' instead of 'std::vector<...>',
this commit fixes this mistake. There should be no user visible
changes after this commit.
gdb/ChangeLog:
* btrace.c (btrace_add_pc): Remove whitespace before the template
parameter in 'std::vector <...>'.
(parse_xml_btrace_block): Likewise.
(btrace_maint_decode_pt): Likewise.
(btrace_maint_update_packets): Likewise.
(btrace_maint_print_packets): Likewise.
* btrace.h (struct btrace_maint_info): Likewise.
* dwarf2read.c (struct type_unit_group): Likewise.
(build_type_psymtabs_reader): Likewise.
* gdbsupport/btrace-common.c (btrace_data_append): Likewise.
* gdbsupport/btrace-common.h (struct btrace_data_bts): Likewise.
* nat/linux-btrace.c (perf_event_read_bts): Likewise.
startup_with_shell was changed to be of "bool" type, but I noticed
that the definition in gdbserver disagreed. This disagreement caused
some regressions on a big-endian machine.
This patch removes the redundant declaration and definition of
startup_with_shell and ensures that such clashes will be diagnosed.
This moves the declaration to common-inferior.h, and introduces a new
common-inferior.c, as suggested by Pedro.
gdb/ChangeLog
2019-10-02 Tom Tromey <tromey@adacore.com>
* Makefile.in (COMMON_SFILES): Add common-inferior.c.
* gdbsupport/common-inferior.c: New file.
* infcmd.c (startup_with_shell): Don't define.
* nat/fork-inferior.h (startup_with_shell): Don't declare.
* gdbsupport/common-inferior.h (startup_with_shell): Declare.
* inferior.h (startup_with_shell): Don't declare.
gdb/gdbserver/ChangeLog
2019-10-02 Tom Tromey <tromey@adacore.com>
* Makefile.in (SFILES): Add common-inferior.c.
(OBS): Add common-inferior.o.
* server.c (startup_with_shell): Don't define.
Converts a VEC into a std::vector in gdbsupport/btrace-common.h. This
commit just performs a mechanical conversion and doesn't do any
refactoring. One consequence of this is that the std::vector must
actually be a pointer to std::vector as it is placed within a union.
It might be possible in future to refactor to a class hierarchy and
remove the need for a union, but I'd rather have that be a separate
change to make it easier to see the evolution of the code.
gdb/ChangeLog:
* btrace.c (btrace_compute_ftrace_bts): Update for std::vector,
make accesses into the vector constant references.
(btrace_add_pc): Update for std::vector.
(btrace_stitch_bts): Likewise.
(parse_xml_btrace_block): Likewise.
(btrace_maint_update_packets): Likewise.
(btrace_maint_print_packets): Likewise.
(maint_info_btrace_cmd): Likewise.
* gdbsupport/btrace-common.c (btrace_data::fini): Update for
std::vector.
(btrace_data::empty): Likewise.
(btrace_data_append): Likewise.
* gdbsupport/btrace-common.h: Remove use of DEF_VEC_O.
(typedef btrace_block_s): Delete.
(struct btrace_block): Add constructor.
(struct btrace_data_bts) <blocks>: Change to std::vector.
* nat/linux-btrace.c (perf_event_read_bts): Update for
std::vector.
(linux_read_bts): Likewise.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_low_read_btrace): Update for change to
std::vector.
In Fedora GDB, we carry the following patch:
8ac06474ff/f/gdb-attach-fail-reasons-5of5.patch
Its purpose is to try to detect a specific scenario where SELinux's
'deny_ptrace' option is enabled, which prevents GDB from ptrace'ing in
order to debug the inferior (PTRACE_ATTACH and PTRACE_TRACEME will
fail with EACCES in this case).
I like the idea of improving error detection and providing more
information to the user (a simple "Permission denied" can be really
frustrating), but I don't fully agree with the way the patch was
implemented: it makes GDB link against libselinux only for the sake of
consulting the 'deny_ptrace' setting, and then prints a warning if
ptrace failed and this setting is on.
My first thought (and attempt) was to make GDB print a generic warning
when a ptrace error happened; this message would just point the user
to our documentation, where she could find more information about
possible causes for the error (and try to diagnose/fix the problem).
This proved to be too simple, and I was convinced that it is actually
a good idea to go the extra kilometre and try to pinpoint the specific
problem (or problems) preventing ptrace from working, as well as
provide useful suggestions on how the user can fix things.
Here is the patch I came up with. It implements a new function,
'linux_ptrace_restricted_fail_reason', which does a few things to
check what's wrong with ptrace:
- It dlopen's "libselinux.so.1" and checks if the "deny_ptrace"
option is enabled.
- It reads the contents of "/proc/sys/kernel/yama/ptrace_scope" and
checks if it's different than 0.
For each of these checks, if it succeeds, the user will see a message
informing about the restriction in place, and how it can be disabled.
For example, if "deny_ptrace" is enabled, the user will see:
# gdb /usr/bin/true
...
Starting program: /usr/bin/true
warning: Could not trace the inferior process.
warning: ptrace: Permission denied
The SELinux 'deny_ptrace' option is enabled and preventing GDB
from using 'ptrace'. You can disable it by executing (as root):
setsebool deny_ptrace off
If you are debugging the inferior remotely, the ptrace restriction(s) need
to be disabled in the target system (e.g., where GDBserver is running).
During startup program exited with code 127.
(gdb)
In case "/proc/sys/kernel/yama/ptrace_scope" is > 0:
# gdb /usr/bin/true
...
Starting program: /usr/bin/true
warning: Could not trace the inferior process.
warning: ptrace: Operation not permitted
The Linux kernel's Yama ptrace scope is in effect, which can prevent
GDB from using 'ptrace'. You can disable it by executing (as root):
echo 0 > /proc/sys/kernel/yama/ptrace_scope
If you are debugging the inferior remotely, the ptrace restriction(s) need
to be disabled in the target system (e.g., where GDBserver is running).
During startup program exited with code 127.
(gdb)
If both restrictions are enabled, both messages will show up.
This works for gdbserver as well, and actually fixes a latent bug I
found: when ptrace is restricted, gdbserver would hang due to an
unchecked ptrace call:
# gdbserver :9988 /usr/bin/true
gdbserver: linux_ptrace_test_ret_to_nx: Cannot PTRACE_TRACEME: Operation not permitted
gdbserver: linux_ptrace_test_ret_to_nx: status 256 is not WIFSTOPPED!
gdbserver: linux_ptrace_test_ret_to_nx: failed to kill child pid 2668100 No such process
[ Here you would have to issue a C-c ]
Now, you will see:
# gdbserver :9988 /usr/bin/true
gdbserver: linux_ptrace_test_ret_to_nx: Cannot PTRACE_TRACEME: Permission denied
gdbserver: linux_ptrace_test_ret_to_nx: status 256 is not WIFSTOPPED!
gdbserver: linux_ptrace_test_ret_to_nx: failed to kill child pid 2766868 No such process
gdbserver: Could not trace the inferior process.
gdbserver: ptrace: Permission denied
The SELinux 'deny_ptrace' option is enabled and preventing GDB
from using 'ptrace'. You can disable it by executing (as root):
setsebool deny_ptrace off
If you are debugging the inferior remotely, the ptrace restriction(s) need
to be disabled in the target system (e.g., where GDBserver is running).
#
(I decided to keep all the other messages, even though I find them a
bit distracting).
If GDB can't determine the cause for the failure, it will still print
the generic error message which tells the user to check our
documentation:
There might be restrictions preventing ptrace from working. Please see
the appendix "Linux kernel ptrace restrictions" in the GDB documentation
for more details.
If you are debugging the inferior remotely, the ptrace restriction(s) need
to be disabled in the target system (e.g., where GDBserver is running).
This means that the patch expands our documentation and creates a new
appendix section named "Linux kernel ptrace restrictions", with
sub-sections for each possible restriction that might be in place.
Notice how, on every message, we instruct the user to "do the right
thing" if gdbserver is being used. This is because if the user
started gdbserver *before* any ptrace restriction was in place, and
then, for some reason, one or more restrictions get enabled, then the
error message will be displayed both on gdbserver *and* on the
connected GDB. Since the user will be piloting GDB, it's important to
explicitly say that the ptrace restrictions are enabled in the target,
where gdbserver is running.
The current list of possible restrictions is:
- SELinux's 'deny_ptrace' option (detected).
- YAMA's /proc/sys/kernel/yama/ptrace_scope setting (detected).
- seccomp on Docker containers (I couldn't find how to detect).
It's important to mention that all of this is Linux-specific; as far
as I know, SELinux, YAMA and seccomp are Linux-only features.
I tested this patch locally, on my Fedora 30 machine (actually, a
Fedora Rawhide VM), but I'm not proposing a testcase for it because of
the difficulty of writing one.
WDYT?
gdb/doc/ChangeLog:
2019-09-26 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.texinfo (Linux kernel ptrace restrictions): New appendix
section.
gdb/ChangeLog:
2019-09-26 Sergio Durigan Junior <sergiodj@redhat.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
Pedro Alves <palves@redhat.com>
* gdbsupport/gdb-dlfcn.h (gdb_dlopen): Update comment and
mention that the function throws an error.
* inf-ptrace.c (default_inf_ptrace_me_fail_reason): New
function.
(inf_ptrace_me_fail_reason): New variable.
(inf_ptrace_me): Update call to 'trace_start_error_with_name'.
* inf-ptrace.h (inf_ptrace_me_fail_reason): New variable.
* linux-nat.c (attach_proc_task_lwp_callback): Call
'linux_ptrace_attach_fail_reason_lwp'.
(linux_nat_target::attach): Update call to
'linux_ptrace_attach_fail_reason'.
(_initialize_linux_nat): Set 'inf_ptrace_me_fail_reason'.
* nat/fork-inferior.c (trace_start_error_with_name): Add
optional 'append' argument.
* nat/fork-inferior.h (trace_start_error_with_name): Update
prototype.
* nat/linux-ptrace.c: Include "gdbsupport/gdb-dlfcn.h",
"gdbsupport/filestuff.h" and "nat/fork-inferior.h".
(selinux_ftype): New typedef.
(linux_ptrace_restricted_fail_reason): New function.
(linux_ptrace_attach_fail_reason_1): New function.
(linux_ptrace_attach_fail_reason): Change first argument type
from 'ptid_t' to 'pid_t'. Call
'linux_ptrace_attach_fail_reason_1' and
'linux_ptrace_restricted_fail_reason'.
(linux_ptrace_attach_fail_reason_lwp): New function.
(linux_ptrace_me_fail_reason): New function.
(errno_pipe): New variable.
(linux_fork_to_function): Initialize pipe before forking.
(linux_child_function): Deal with errno-passing from child.
Handle ptrace error.
(linux_check_child_ptrace_errno): New function.
(linux_check_child_ptrace_errno): Call
'linux_check_child_ptrace_errno'.
* nat/linux-ptrace.h (linux_ptrace_attach_fail_reason): Update
prototype.
(linux_ptrace_attach_fail_reason_lwp): New prototype.
(linux_ptrace_me_fail_reason): New prototype.
* remote.c (extended_remote_target::attach): Handle error
message passed by the server when attach fails.
gdb/gdbserver/ChangeLog:
2019-09-26 Sergio Durigan Junior <sergiodj@redhat.com>
Pedro Alves <palves@redhat.com>
* linux-low.c (linux_ptrace_fun): Call
'linux_ptrace_me_fail_reason'.
(attach_proc_task_lwp_callback): Call
'linux_ptrace_attach_fail_reason_lwp'.
(linux_attach): Call 'linux_ptrace_attach_fail_reason'.
* server.c (handle_v_attach): Use try..catch when calling
'attach_inferior', and send an error message to the client
when needed.
* thread-db.c (attach_thread): Call
'linux_ptrace_attach_fail_reason_lwp'.
Rationale: https://sourceware.org/ml/gdb-patches/2019-08/msg00651.html
This very simple patch removes the "\nError: " suffix from the warning
message printed by nat/fork-inferior.c:trace_start_error. This proved
to just pollute the screen, causing things like:
Starting program: /usr/bin/true
warning: Could not trace the inferior process.
Error:
warning: ptrace: Permission denied
This "Error: " string is not useful at all, and can confuse things,
therefore let's just remove it and simplify the resulting messages:
Starting program: /usr/bin/true
warning: Could not trace the inferior process.
warning: ptrace: Permission denied
gdb/ChangeLog:
2019-08-30 Sergio Durigan Junior <sergiodj@redhat.com>
* nat/fork-inferior.c (trace_start_error): Remove "\nError: "
suffix from warning message.
../../gdb/nat/linux-namespaces.c: In function ‘void mnsh_main(int)’:
../../gdb/nat/linux-namespaces.c:604:8: warning: ‘fd’ may be used uninitialized in this function [-Wmaybe-uninitialized]
close (fd);
~~~~~~^~~~
And the warning is correct -- mnsh_recv_message can return -1 and leave fd
uninitialized, and mnsh_main will still call close (fd) if that happens.
Initialize fd to -1 to avoid that.
gdb/ChangeLog:
2019-08-27 Christian Biesinger <cbiesinger@google.com>
* nat/linux-namespaces.c (mnsh_main): Initialize fd (to -1).
The debugging code in linux-waitpid.c is one of the few remaining
spots that depends on the gdb/gdbserver difference.
My first thought was that this code is not extremely useful, so this
patch removes this code. (However, if it is actually useful to
someone, we could make it work by introducing a new abstraction.)
gdb/ChangeLog
2019-06-11 Tom Tromey <tom@tromey.com>
* nat/linux-waitpid.c: Don't include server.h.
(linux_debug): Remove.
(my_waitpid): Update.
ARI pointed out that a recent patch introduced a call to "warning"
with a string that ended in a newline:
https://sourceware.org/ml/gdb-patches/2019-06/msg00000.html
This is generally forbidden, I believe, because warning adds its own
newline.
This patch removes all of the trailing newlines I was able to find. I
searched for 'warning (.*\\n"' and then fixed the ones where the
newline appeared at the end of the string (some had internal
newlines).
Tested on x86-64 Fedora 29.
gdb/ChangeLog
2019-06-10 Tom Tromey <tromey@adacore.com>
* m32c-tdep.c (m32c_m16c_address_to_pointer): Don't end warning
with a newline.
* guile/guile.c (handle_boot_error): Don't end warning with a
newline.
* cli/cli-cmds.c (exit_status_set_internal_vars): Don't end
warning with a newline.
* s12z-tdep.c (s12z_skip_prologue): Don't end warning with a
newline.
(s12z_frame_cache): Likewise.
* dwarf-index-cache.c (index_cache::store): Don't end warning with
a newline.
* solib-svr4.c (disable_probes_interface): Don't end warning with
a newline.
* nat/fork-inferior.c (fork_inferior): Don't end warning with a
newline.
* python/python.c (do_finish_initialization): Don't end warning
with a newline.
gdb/gdbserver/ChangeLog
2019-06-10 Tom Tromey <tromey@adacore.com>
* remote-utils.c (look_up_one_symbol, relocate_instruction): Don't
end warning with a newline.
* linux-s390-low.c (s390_get_wordsize): Don't end warning with a
newline.
* thread-db.c (attach_thread): Don't end warning with a newline.
(thread_db_notice_clone): Likewise.
* tracepoint.c (gdb_agent_helper_thread): Don't end warning with a
newline.
* linux-x86-low.c (x86_get_min_fast_tracepoint_insn_len): Don't
end warning with a newline.
All debug output needs to go via debug functions to ensure it writes to the
correct output stream.
gdb/ChangeLog:
* nat/linux-waitpid.c (linux_debug): Call debug_vprintf.
gdb/gdbserver/ChangeLog:
* ax.c (ax_vdebug): Call debug_printf.
* debug.c (debug_write): New function.
* debug.h (debug_write): New declaration.
* linux-low.c (sigchld_handler): Call debug_write.
Kevin Buettner
Tom Tromey
Hannes Domani
Simon Marchi
Luis Machado
Andrew Burgess
Maciej W. Rozycki
Christian Biesinger
Tom Tromey
Pedro Alves
Joel Brobecker
Tom de Vries
Sergio Durigan Junior
Ulrich Weigand
Alan Hayward