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'.
Adds an utility function to make it shorter to write the common case
of wrapping an xstrdup with a unique_xmalloc_ptr, and uses it
throughout.
Note: I tried to put this in common/common-utils.h near skip_spaces,
etc. but that is included in common/common-defs.h before
common/gdb_unique_ptr.h is included, so it would fail to compile
because gdb::unique_xmalloc_ptr isn't defined at that point yet. I
tried moving the gdb_unique_ptr.h inclusion before common-utils.h, but
that doesn't work because gdb_unique_ptr.h depends on common-utils.h
for xfree.
gdb/ChangeLog:
2019-06-04 Pedro Alves <palves@redhat.com>
* common/gdb_unique_ptr.h (make_unique_xstrdup): New.
* ada-lang.c (catch_ada_completer): Use make_unique_xstrdup.
* breakpoint.c (condition_completer): Likewise.
* cli/cli-dump.c (scan_expression): Likewise.
* common/filestuff.c (mkdir_recursive): Likewise.
* common/gdb_tilde_expand.c (gdb_tilde_expand_up)
* common/pathstuff.c (gdb_realpath, gdb_realpath_keepfile)
(gdb_abspath): Likewise.
* compile/compile-cplus-types.c
(compile_cplus_instance::decl_name): Likewise.
* completer.c (complete_explicit_location):
(signal_completer, reg_or_group_completer_1): Likewise.
* cp-support.c (cp_remove_params_if_any): Likewise.
* fbsd-tdep.c (fbsd_core_vnode_path): Likewise.
* guile/scm-safe-call.c (gdbscm_safe_eval_string): Likewise.
* infcmd.c (strip_bg_char): Likewise.
* linespec.c (copy_token_string): Likewise.
* mi/mi-main.c (output_cores): Likewise.
* psymtab.c (psymtab_search_name):
* symfile.c (test_set_ext_lang_command): Likewise.
* target.c (target_fileio_read_stralloc): Likewise.
* tui/tui-regs.c (tui_reggroup_completer): Likewise.
* value.c (complete_internalvar): Likewise.
gdb/gdbserver/ChangeLog:
2019-06-04 Pedro Alves <palves@redhat.com>
* server.c (captured_main): Use make_unique_xstrdup.
A comment in debug.h (written in 2014) states: "We declare debug format
variables here, and debug_threads but no other debug content variables
(e.g., not remote_debug) because while this file is not currently used by
IPA it may be some day, and IPA may have its own set of debug content
variables".
This has resulted in remote_debug being declared in many .c/.h files
throughout gdbserver.
It would be much simplier to define it one place. The most logical place to
define it is in debug.h, surrounded by #define guards. If IPA is changed,
then at that point the variable can be moved elsewhere.
gdb/gdbserver/ChangeLog:
* debug.c (remote_debug): Add definition.
* debug.h (remote_debug): Add declaration.
* hostio.c (remote_debug): Remove declaration.
* remote-utils.c (struct ui_file): Likewise.
(remote_debug): Likewise.
* remote-utils.h (remote_debug): Likewise,
* server.c (remote_debug): Remove definition.
This rewrites gdb's TRY/CATCH to plain C++ try/catch. The patch was
largely written by script, though one change (to a comment in
common-exceptions.h) was reverted by hand.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c: Use C++ exception handling.
* x86-linux-nat.c: Use C++ exception handling.
* windows-nat.c: Use C++ exception handling.
* varobj.c: Use C++ exception handling.
* value.c: Use C++ exception handling.
* valprint.c: Use C++ exception handling.
* valops.c: Use C++ exception handling.
* unittests/parse-connection-spec-selftests.c: Use C++ exception
handling.
* unittests/cli-utils-selftests.c: Use C++ exception handling.
* typeprint.c: Use C++ exception handling.
* tui/tui.c: Use C++ exception handling.
* tracefile-tfile.c: Use C++ exception handling.
* top.c: Use C++ exception handling.
* thread.c: Use C++ exception handling.
* target.c: Use C++ exception handling.
* symmisc.c: Use C++ exception handling.
* symfile-mem.c: Use C++ exception handling.
* stack.c: Use C++ exception handling.
* sparc64-linux-tdep.c: Use C++ exception handling.
* solib.c: Use C++ exception handling.
* solib-svr4.c: Use C++ exception handling.
* solib-spu.c: Use C++ exception handling.
* solib-frv.c: Use C++ exception handling.
* solib-dsbt.c: Use C++ exception handling.
* selftest-arch.c: Use C++ exception handling.
* s390-tdep.c: Use C++ exception handling.
* rust-lang.c: Use C++ exception handling.
* rust-exp.y: Use C++ exception handling.
* rs6000-tdep.c: Use C++ exception handling.
* rs6000-aix-tdep.c: Use C++ exception handling.
* riscv-tdep.c: Use C++ exception handling.
* remote.c: Use C++ exception handling.
* remote-fileio.c: Use C++ exception handling.
* record-full.c: Use C++ exception handling.
* record-btrace.c: Use C++ exception handling.
* python/python.c: Use C++ exception handling.
* python/py-value.c: Use C++ exception handling.
* python/py-utils.c: Use C++ exception handling.
* python/py-unwind.c: Use C++ exception handling.
* python/py-type.c: Use C++ exception handling.
* python/py-symbol.c: Use C++ exception handling.
* python/py-record.c: Use C++ exception handling.
* python/py-record-btrace.c: Use C++ exception handling.
* python/py-progspace.c: Use C++ exception handling.
* python/py-prettyprint.c: Use C++ exception handling.
* python/py-param.c: Use C++ exception handling.
* python/py-objfile.c: Use C++ exception handling.
* python/py-linetable.c: Use C++ exception handling.
* python/py-lazy-string.c: Use C++ exception handling.
* python/py-infthread.c: Use C++ exception handling.
* python/py-inferior.c: Use C++ exception handling.
* python/py-gdb-readline.c: Use C++ exception handling.
* python/py-framefilter.c: Use C++ exception handling.
* python/py-frame.c: Use C++ exception handling.
* python/py-finishbreakpoint.c: Use C++ exception handling.
* python/py-cmd.c: Use C++ exception handling.
* python/py-breakpoint.c: Use C++ exception handling.
* python/py-arch.c: Use C++ exception handling.
* printcmd.c: Use C++ exception handling.
* ppc-linux-tdep.c: Use C++ exception handling.
* parse.c: Use C++ exception handling.
* p-valprint.c: Use C++ exception handling.
* objc-lang.c: Use C++ exception handling.
* mi/mi-main.c: Use C++ exception handling.
* mi/mi-interp.c: Use C++ exception handling.
* mi/mi-cmd-stack.c: Use C++ exception handling.
* mi/mi-cmd-break.c: Use C++ exception handling.
* main.c: Use C++ exception handling.
* linux-thread-db.c: Use C++ exception handling.
* linux-tdep.c: Use C++ exception handling.
* linux-nat.c: Use C++ exception handling.
* linux-fork.c: Use C++ exception handling.
* linespec.c: Use C++ exception handling.
* language.c: Use C++ exception handling.
* jit.c: Use C++ exception handling.
* infrun.c: Use C++ exception handling.
* infcmd.c: Use C++ exception handling.
* infcall.c: Use C++ exception handling.
* inf-loop.c: Use C++ exception handling.
* i386-tdep.c: Use C++ exception handling.
* i386-linux-tdep.c: Use C++ exception handling.
* guile/scm-value.c: Use C++ exception handling.
* guile/scm-type.c: Use C++ exception handling.
* guile/scm-symtab.c: Use C++ exception handling.
* guile/scm-symbol.c: Use C++ exception handling.
* guile/scm-pretty-print.c: Use C++ exception handling.
* guile/scm-ports.c: Use C++ exception handling.
* guile/scm-param.c: Use C++ exception handling.
* guile/scm-math.c: Use C++ exception handling.
* guile/scm-lazy-string.c: Use C++ exception handling.
* guile/scm-frame.c: Use C++ exception handling.
* guile/scm-disasm.c: Use C++ exception handling.
* guile/scm-cmd.c: Use C++ exception handling.
* guile/scm-breakpoint.c: Use C++ exception handling.
* guile/scm-block.c: Use C++ exception handling.
* guile/guile-internal.h: Use C++ exception handling.
* gnu-v3-abi.c: Use C++ exception handling.
* gdbtypes.c: Use C++ exception handling.
* frame.c: Use C++ exception handling.
* frame-unwind.c: Use C++ exception handling.
* fbsd-tdep.c: Use C++ exception handling.
* f-valprint.c: Use C++ exception handling.
* exec.c: Use C++ exception handling.
* event-top.c: Use C++ exception handling.
* event-loop.c: Use C++ exception handling.
* eval.c: Use C++ exception handling.
* dwarf2read.c: Use C++ exception handling.
* dwarf2loc.c: Use C++ exception handling.
* dwarf2-frame.c: Use C++ exception handling.
* dwarf2-frame-tailcall.c: Use C++ exception handling.
* dwarf-index-write.c: Use C++ exception handling.
* dwarf-index-cache.c: Use C++ exception handling.
* dtrace-probe.c: Use C++ exception handling.
* disasm-selftests.c: Use C++ exception handling.
* darwin-nat.c: Use C++ exception handling.
* cp-valprint.c: Use C++ exception handling.
* cp-support.c: Use C++ exception handling.
* cp-abi.c: Use C++ exception handling.
* corelow.c: Use C++ exception handling.
* completer.c: Use C++ exception handling.
* compile/compile-object-run.c: Use C++ exception handling.
* compile/compile-object-load.c: Use C++ exception handling.
* compile/compile-cplus-symbols.c: Use C++ exception handling.
* compile/compile-c-symbols.c: Use C++ exception handling.
* common/selftest.c: Use C++ exception handling.
* common/new-op.c: Use C++ exception handling.
* cli/cli-script.c: Use C++ exception handling.
* cli/cli-interp.c: Use C++ exception handling.
* cli/cli-cmds.c: Use C++ exception handling.
* c-varobj.c: Use C++ exception handling.
* btrace.c: Use C++ exception handling.
* breakpoint.c: Use C++ exception handling.
* break-catch-throw.c: Use C++ exception handling.
* arch-utils.c: Use C++ exception handling.
* amd64-tdep.c: Use C++ exception handling.
* ada-valprint.c: Use C++ exception handling.
* ada-typeprint.c: Use C++ exception handling.
* ada-lang.c: Use C++ exception handling.
* aarch64-tdep.c: Use C++ exception handling.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c: Use C++ exception handling.
* linux-low.c: Use C++ exception handling.
* gdbreplay.c: Use C++ exception handling.
I noticed that "gdbserver --help" contains a few metasyntactic
variables that aren't in upper-case. This patch fixes them to conform
to the GNU standard.
gdb/gdbserver/ChangeLog
2019-04-05 Tom Tromey <tromey@adacore.com>
* server.c (gdbserver_usage): Use upper-case for metasyntactic
variables.
This removes the last cleanup from gdbserver, replacing it with
SCOPE_EXIT. This could perhaps be done in a different way, but this
approach was direct and obviously correct.
2019-03-06 Tom Tromey <tom@tromey.com>
* server.c (detach_or_kill_for_exit_cleanup): Remove parameter.
(captured_main): Use SCOPE_EXIT.
The recent BP/WP changes for AArch64 swapping the order in add_lwp()
so that the process was added before the lwp. This was due to the lwp
creation requiring the process data.
This also needs changing in linux_attach().
Also add additional checks to make sure cannot attach to the same
process twice. Add test case for this - do this by splitting
attach.exp into distinct pass and error case sections.
Fixes gdb.server/ext-attach.exp on Aarch64.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_attach): Add process before lwp.
* server.c (attach_inferior): Check if already attached.
gdb/testsuite/ChangeLog:
* gdb.base/attach.exp: Add double attach test.
gdb/ChangeLog:
* top.c (print_gdb_version): Update Copyright year in version
message.
gdb/gdbserver/ChangeLog:
* gdbreplay.c (gdbreplay_version): Update copyright year in
version message.
* server.c (gdbserver_version): Likewise.
This commit applies all changes made after running the gdb/copyright.py
script.
Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.
gdb/ChangeLog:
Update copyright year range in all GDB files.
-fsanitize=address pointed out a use-after-free in gdbserver. In
particular, handle_detach could reference "process" after it was
deleted by detach_inferior. Avoiding this also necessitated changing
target_ops::join to take a pid rather than a process_info*.
Tested by the buildbot using a few of the gdbserver builders.
gdb/gdbserver/ChangeLog
2018-11-29 Tom Tromey <tom@tromey.com>
* win32-low.c (win32_join): Take pid, not process.
* target.h (struct target_ops) <join>: Change argument type.
(join_inferior): Change argument name.
* spu-low.c (spu_join): Take pid, not process.
* server.c (handle_detach): Preserve pid before destroying
process.
* lynx-low.c (lynx_join): Take pid, not process.
* linux-low.c (linux_join): Take pid, not process.
This is a follow-up of:
https://sourceware.org/ml/gdb-patches/2018-08/msg00347.html
Instead of going throttle and always enabling our selftests (even in
non-development builds), this patch is a bit more conservative and
introduces a configure option ("--enable-unit-tests") that allows the
user to choose whether she wants unit tests in the build or not. Note
that the current behaviour is retained: if no option is provided, GDB
will have selftests included in a development build, and will *not*
have selftests included in a non-development build.
The rationale for having this option is still the same: due to the
many racy testcases and random failures we see when running the GDB
testsuite, it is unfortunately not possible to perform a full test
when one is building a downstream package. As the Fedora GDB
maintainer and one of the Debian GDB uploaders, I feel like this
situation could be improved by, at least, executing our selftests
after the package has been built.
This patch introduces no regressions to our build.
OK?
gdb/ChangeLog:
2018-10-10 Sergio Durigan Junior <sergiodj@redhat.com>
Simon Marchi <simark@simark.ca>
* README (`configure' options): Add documentation for new
"--enable-unit-tests" option.
* acinclude.m4: Include "selftest.m4".
* configure: Regenerate.
* configure.ac: Use "GDB_AC_SELFTEST".
* maint.c (maintenance_selftest): Update message informing
that selftests have been disabled.
(maintenance_info_selftests): Likewise.
* selftest.m4: New file.
gdb/gdbserver/ChangeLog:
2018-10-10 Sergio Durigan Junior <sergiodj@redhat.com>
Simon Marchi <simark@simark.ca>
* acinclude.m4: Include "../selftest.m4".
* configure: Regenerate.
* configure.ac: Use "GDB_AC_SELFTEST".
* configure.srv: Use "$enable_unittests" instead of
"$development" when checking whether unit tests have been
enabled.
* server.c (captured_main): Update message informing that
selftests have been disabled.
gdb/testsuite/ChangeLog:
2018-10-10 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.gdb/unittest.exp: Update expected message informing that
selftests have been disabled.
* gdb.server/unittest.exp: Likewise.
squash! Add parameter to allow enabling/disabling selftests via configure
This fixes a few instances of shadowing in gdbserver. These are all
simple fixes.
gdb/gdbserver/ChangeLog
2018-10-04 Tom Tromey <tom@tromey.com>
* server.c (handle_status): Rename inner "thread".
(process_serial_event): Declare "res" in 'm' case.
* linux-low.c (last_thread_of_process_p, find_lwp_pid)
(iterate_over_lwps): Rename inner "thread".
(linux_qxfer_libraries_svr4): Rename inner "len".
* gdbthread.h (find_thread_in_random): Rename inner "thread".
We start from a process_info pointer, pass down process->pid, and
then the target_kill implementations need to find the process from the
pid again. Pass the process_info pointer down directly instead.
gdb/gdbserver/ChangeLog:
2018-07-13 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_kill): Change parameter to process_info
pointer instead of pid. Adjust.
* lynx-low.c (lynx_kill): Likewise.
* nto-low.c (nto_kill): Likewise.
* spu-low.c (spu_kill): Likewise.
* win32-low.c (win32_kill): Likewise.
* server.c (handle_v_kill, kill_inferior_callback)
(detach_or_kill_for_exit): Adjust.
* target.c (kill_inferior): Change parameter to process_info
pointer instead of pid. Adjust.
* target.h (struct target_ops) <kill>: Change parameter to
process_info pointer instead of pid. Adjust all implementations
and callers.
(kill_inferior): Likewise.
We start from a process_info pointer, pass down process->pid, and then
the target_detach and target_join implementations need to find the
process from the pid again. Pass the process_info pointer down
directly instead.
gdb/gdbserver/ChangeLog:
2018-07-13 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_detach, linux_join): Change parameter to
process_info pointer instead of pid. Adjust.
* lynx-low.c (lynx_detach, lynx_join): Likewise.
* nto-low.c (nto_detach): Likewise.
* spu-low.c (spu_detach, spu_join): Likewise.
* win32-low.c (win32_detach, win32_join): Likewise.
* server.c (handle_detach, detach_or_kill_for_exit): Adjust.
* target.h (struct target_ops) <detach, join>: Change parameter to
process_info pointer instead of pid. Adjust all implementations
and callers.
(detach_inferior, join_inferior): Rename 'pid' parameter to
'proc'.
This fixes a gdb.base/multi-forks.exp regression with GDBserver.
Git commit f2ffa92bbc ("gdb: Eliminate the 'stop_pc' global") caused
the regression by exposing a latent bug in gdbserver.
The bug is that GDBserver's implementation of the D;PID packet
incorrectly assumes that the selected thread points to the process
being detached. This happens via the any_persistent_commands call,
which calls current_process:
(gdb) bt
#0 0x000000000040a57e in internal_error(char const*, int, char const*, ...)
(file=0x4a53c0 "src/gdb/gdbserver/inferiors.c", line=212, fmt=0x4a539e "%s:
Assertion `%s' failed.") at src/gdb/gdbserver/../common/errors.c:54
#1 0x0000000000420acf in current_process() () at
src/gdb/gdbserver/inferiors.c:212
#2 0x00000000004226a0 in any_persistent_commands() () at
gdb/gdbserver/mem-break.c:308
#3 0x000000000042cb43 in handle_detach(char*) (own_buf=0x6f0280 "D;62ea") at
src/gdb/gdbserver/server.c:1210
#4 0x0000000000433af3 in process_serial_event() () at
src/gdb/gdbserver/server.c:4055
#5 0x0000000000434878 in handle_serial_event(int, void*) (err=0,
client_data=0x0)
The "eliminate stop_pc" commit exposes the problem because before that
commit, GDB's switch_to_thread always read the newly-selected thread's
PC, and that would end up forcing GDBserver's selected thread to
change accordingly as side effect. After that commit, GDB no longer
reads the thread's PC, and GDBserver does not switch the thread.
Fix this by removing the assumption from GDBserver.
gdb/gdbserver/ChangeLog:
2018-07-11 Pedro Alves <palves@redhat.com>
PR gdb/23377
* mem-break.c (any_persistent_commands): Add process_info
parameter and use it instead of relying on the current process.
Change return type to bool.
* mem-break.h (any_persistent_commands): Add process_info
parameter and change return type to bool.
* server.c (handle_detach): Remove require_running_or_return call.
Look up the process_info for the process we're about to detach.
If not found, return back error to GDB. Adjust
any_persistent_commands call to pass down a process pointer.
Collect per client specific global data items into struct client_state,
which is similar in purpose to remote.c::remote_state.
gdbserver/ChangeLog
* server.h (struct client_state): New.
* server.c (cont_thread, general_thread, multi_process)
(report_fork_events, report_vfork_events, report_exec_events)
(report_thread_events, swbreak_feature, hwbreak_feature)
(vCont_supported, disable_randomization, pass_signals)
(program_signals, program_signals_p, last_status, last_ptid, own_buf):
Moved to client_state.
* remote-utils.c (remote_debug, noack_mode)
(transport_is_reliable): Moved to client_state.
* tracepoint.c (current_traceframe): Moved to client_state.
Update all callers.
* server.c, remote-utils.c, tracepoint.c, fork-child.c,
linux-low.c, remote-utils.h, target.c: Use client_state.
Add a print_xml_feature visitor class which turns a
target description into xml. Both gdb and gdbserver can do this.
gdb/
* common/tdesc.c (print_xml_feature::visit_pre): Add xml parsing.
(print_xml_feature::visit_post): Likewise.
(print_xml_feature::visit): Likewise.
* common/tdesc.h (tdesc_get_features_xml): Use const tdesc.
(print_xml_feature): Add new class.
* regformats/regdat.sh: Null xmltarget on feature targets.
* target-descriptions.c (struct target_desc): Add xmltarget.
(maintenance_check_tdesc_xml_convert): Add unittest function.
(tdesc_get_features_xml): Add function to get xml.
(maintenance_check_xml_descriptions): Test xml generation.
* xml-tdesc.c (string_read_description_xml): Add function.
* xml-tdesc.h (string_read_description_xml): Add declaration.
gdbserver/
* gdb/gdbserver/server.c (get_features_xml): Remove cast.
* tdesc.c (void target_desc::accept): Fill in function.
(tdesc_get_features_xml): Remove old xml creation.
(print_xml_feature::visit_pre): Add xml vistor.
* tdesc.h (struct target_desc): Make xmltarget mutable.
(tdesc_get_features_xml): Remove declaration.
Unless I'm missing something very obvious, this xstrdup seems
unnecessary to me. We can pass "mode" directly to sprintf.
gdb/gdbserver/ChangeLog:
* server.c (handle_general_set): Remove unnecessary xstrdup.
This patch makes delim_string_to_char_ptr_vec and all related functions
use std::vector of gdb::unique_xmalloc_ptr. This allows getting rid of
make_cleanup_free_char_ptr_vec. Returning a vector of
unique_xmalloc_ptr instead of std::string allows to minimize the impacts
on the calling code. We can evaluate later whether we could/should
return a vector of std::strings instead.
gdb/ChangeLog:
* common/gdb_vecs.h (make_cleanup_free_char_ptr_vec): Remove.
(delim_string_to_char_ptr_vec): Return std::vector of
gdb::unique_xmalloc_ptr.
(dirnames_to_char_ptr_vec_append): Take std::vector of
gdb::unique_xmalloc_ptr.
(dirnames_to_char_ptr_vec): Return std::vector of
gdb::unique_xmalloc_ptr.
* common/gdb_vecs.c (delim_string_to_char_ptr_vec_append):
Take std::vector of gdb::unique_xmalloc_ptr, adjust the code.
(delim_string_to_char_ptr_vec): Return an std::vector of
gdb::unique_xmalloc_ptr, adjust the code.
(dirnames_to_char_ptr_vec_append): Take an std::vector of
gdb::unique_xmalloc_ptr, adjust the code.
(dirnames_to_char_ptr_vec): Return an std::vector of
gdb::unique_xmalloc_ptr, adjust the code.
* auto-load.c (auto_load_safe_path_vec): Change type to
std::vector of gdb::unique_xmalloc_ptr.
(auto_load_expand_dir_vars): Return an std::vector of
gdb::unique_xmalloc_ptr, adjust the code.
(auto_load_safe_path_vec_update): Adjust.
(filename_is_in_auto_load_safe_path_vec): Adjust.
(auto_load_objfile_script_1): Adjust.
* build-id.c (build_id_to_debug_bfd): Adjust.
* linux-thread-db.c (thread_db_load_search): Adjust.
* source.c (add_path): Adjust.
(openp): Adjust.
* symfile.c (find_separate_debug_file): Adjust.
* utils.c (do_free_char_ptr_vec): Remove.
(make_cleanup_free_char_ptr_vec): Remove.
gdb/gdbserver/ChangeLog:
* server.c (parse_debug_format_options): Adjust to
delim_string_to_char_ptr_vec changes.
* thread-db.c (thread_db_load_search): Adjust to
dirnames_to_char_ptr_vec changes.
By removing the supports_btrace gdbserver target method we relied on GDB
trying to enable branch tracing and failing on the attempt.
For targets that do not provide the btrace methods, however, an initial
request from GDB for the branch trace configuration to detect whether
gdbserver is already recording resulted in a protocol error.
Have the btrace target methods throw a "Target does not suppor branch
tracing" error and be prepared to handle exceptions in all functions that
call btrace target methods. We therefore turn the target_* macros into
static inline functions.
Also remove the additional btrace target method checks that resulted in
the above protocol error.
Thanks to Maciej W. Rozycki <macro@mips.com> for reporting this.
gdbserver/
* target.h (target_enable_btrace, target_disable_btrace)
(target_read_btrace, target_read_btrace_conf): Turn macro into
inline function. Throw error if target method is not defined.
* server.c (handle_qxfer_btrace, handle_qxfer_btrace_conf): Remove
check for btrace target method. Be prepared to handle exceptions
from btrace target methods.
I forgot to address Pedro's comment about my last patch and change the
order of the message printed when getcwd returns NULL on gdbserver.
This obvious commit does it.
gdb/gdbserver/ChangeLog:
2018-02-28 Sergio Durigan Junior <sergiodj@redhat.com>
* server.c (captured_main): Change order of error message printed
when the current working directory cannot be found.
Simon mentioned on IRC that, after the startup-with-shell feature has
been implemented on gdbserver, it is not possible to specify a
filename-only binary, like:
$ gdbserver :1234 a.out
/bin/bash: line 0: exec: a.out: not found
During startup program exited with code 127.
Exiting
This happens on systems where the current directory "." is not listed
in the PATH environment variable. Although including "." in the PATH
variable is a possible workaround, this can be considered a regression
because before startup-with-shell it was possible to use only the
filename (due to reason that gdbserver used "exec*" directly).
The idea of the patch is to verify if the program path provided by the
user (or by the remote protocol) contains a directory separator
character. If it doesn't, it means we're dealing with a filename-only
binary, so we call "gdb_abspath" to properly expand it and transform
it into a full path. Otherwise, we leave the program path untouched.
This mimicks the behaviour seen on GDB (look at "openp" and
"attach_inferior", for example).
I am also submitting a testcase which exercises the scenario described
above. This test requires gdbserver to be executed in a different CWD
than the original, so I also created a helper function, "with_cwd" (on
testsuite/lib/gdb.exp), which takes care of cd'ing into and out of the
specified dir.
Built and regtested on BuildBot, without regressions.
gdb/ChangeLog:
2018-02-28 Sergio Durigan Junior <sergiodj@redhat.com>
Simon Marchi <simon.marchi@polymtl.ca>
* common/common-utils.c: Include "sys/stat.h".
(is_regular_file): Move here from "source.c"; change return
type to "bool".
* common/common-utils.h (is_regular_file): New prototype.
* common/pathstuff.c (contains_dir_separator): New function.
* common/pathstuff.h (contains_dir_separator): New prototype.
* source.c: Don't include "sys/stat.h".
(is_regular_file): Move to "common/common-utils.c".
gdb/gdbserver/ChangeLog:
2018-02-28 Sergio Durigan Junior <sergiodj@redhat.com>
* server.c: Include "filenames.h" and "pathstuff.h".
(program_name): Delete variable.
(program_path): New anonymous class.
(get_exec_wrapper): Use "program_path" instead of
"program_name".
(handle_v_run): Likewise.
(captured_main): Likewise.
(process_serial_event): Likewise.
gdb/testsuite/ChangeLog:
2018-02-28 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.server/abspath.exp: New file.
* lib/gdb.exp (with_cwd): New procedure.
This commit moves the path manipulation routines found on utils.c to a
new common/pathstuff.c, and updates the Makefile.in's accordingly.
The routines moved are "gdb_realpath", "gdb_realpath_keepfile" and
"gdb_abspath".
This will be needed because gdbserver will have to call "gdb_abspath"
on my next patch, which implements a way to expand the path of the
inferior provided by the user in order to allow specifying just the
binary name when starting gdbserver, like:
$ gdbserver :1234 a.out
With the recent addition of the startup-with-shell feature on
gdbserver, this scenario doesn't work anymore if the user doesn't have
the current directory listed in the PATH variable.
I had to do a minor adjustment on "gdb_abspath" because we don't have
access to "tilde_expand" on gdbserver, so now the function is using
"gdb_tilde_expand" instead. Otherwise, the code is the same.
Regression tested on the BuildBot, without regressions.
gdb/ChangeLog:
2018-02-28 Sergio Durigan Junior <sergiodj@redhat.com>
* Makefile.in (COMMON_SFILES): Add "common/pathstuff.c".
(HFILES_NO_SRCDIR): Add "common/pathstuff.h".
* auto-load.c: Include "common/pathstuff.h".
* common/common-def.h (current_directory): Move here.
* common/gdb_tilde_expand.c (gdb_tilde_expand_up): New
function.
* common/gdb_tilde_expand.h (gdb_tilde_expand_up): New
prototype.
* common/pathstuff.c: New file.
* common/pathstuff.h: New file.
* compile/compile.c: Include "common/pathstuff.h".
* defs.h (current_directory): Move to "common/common-defs.h".
* dwarf2read.c: Include "common/pathstuff.h".
* exec.c: Likewise.
* guile/scm-safe-call.c: Likewise.
* linux-thread-db.c: Likewise.
* main.c: Likewise.
* nto-tdep.c: Likewise.
* objfiles.c: Likewise.
* source.c: Likewise.
* symtab.c: Likewise.
* utils.c: Include "common/pathstuff.h".
(gdb_realpath): Move to "common/pathstuff.c".
(gdb_realpath_keepfile): Likewise.
(gdb_abspath): Likewise.
* utils.h (gdb_realpath): Move to "common/pathstuff.h".
(gdb_realpath_keepfile): Likewise.
(gdb_abspath): Likewise.
gdb/gdbserver/ChangeLog:
2018-02-28 Sergio Durigan Junior <sergiodj@redhat.com>
* Makefile.in (SFILES): Add "$(srcdir)/common/pathstuff.c".
(OBJS): Add "pathstuff.o".
* server.c (current_directory): New global variable.
(captured_main): Initialize "current_directory".
Remove the to_supports_btrace target method and instead rely on detecting errors
when trying to enable recording. This will also provide a suitable error
message explaining why recording is not possible.
For remote debugging, gdbserver will now always advertise branch tracing related
packets. When talking to an older GDB, this will cause GDB to try to enable
branch tracing and gdbserver to report a suitable error message every time.
An older gdbserver will not advertise branch tracing related packets if the
one-time check failed, so a newer GDB with this patch will fail to enable branch
tracing at remote_enable_btrace() rather than at btrace_enable(). The error
message is the same in both cases so there should be no user-visible change.
gdb/
* btrace.c (btrace_enable): Remove target_supports_btrace call.
* nat/linux-btrace.c (perf_event_pt_event_type): Move.
(kernel_supports_bts, kernel_supports_pt, linux_supports_bts)
(linux_supports_pt, linux_supports_btrace): Remove.
(linux_enable_bts): Call cpu_supports_bts.
* nat/linux-btrace.h (linux_supports_btrace): Remove.
* remote.c (remote_supports_btrace): Remove.
(init_remote_ops): Remove remote_supports_btrace.
* target-delegates.c: Regenerated.
* target.c (target_supports_btrace): Remove.
* target.h (target_ops) <to_supports_btrace>: Remove
(target_supports_btrace): Remove.
* x86-linux-nat.c (x86_linux_create_target): Remove
linux_supports_btrace.
gdbserver/
* linux-low.c (linux_target_ops): Remove linux_supports_btrace.
* nto-low.c (nto_target_ops): Remove NULL for supports_btrace.
* spu-low.c (spu_target_ops): Likewise.
* win32-low.c (win32_target_ops): Likewise.
* server.c (supported_btrace_packets): Report packets unconditionally.
* target.h (target_ops) <supports_btrace>: Remove.
(target_supports_btrace): Remove.
Change error reporting to use exceptions and be prepared to catch them in
gdbserver. We use the exception message in our error reply to GDB.
This may remove some detail from the error message in the native case since
errno is no longer printed. Later patches will improve that.
We're still using error strings on the RSP level. This patch does not affect
the interoperability of older/newer GDB/gdbserver.
gdbserver/
* server.c (handle_btrace_enable_bts, handle_btrace_enable_pt)
(handle_btrace_disable): Change return type to void. Use exceptions
to report errors.
(handle_btrace_general_set): Catch exception and copy message to
return message.
gdb/
* nat/linux-btrace.c (linux_enable_btrace): Throw exception if enabling
btrace failed.
* x86-linux-nat.c (x86_linux_enable_btrace): Catch btrace enabling
exception and use message in own exception.
When we set bfd/development.sh:$development to false, GDBserver failed to
build,
selftest.o: In function `selftests::run_tests(char const*)':
binutils-gdb/gdb/gdbserver/../common/selftest.c:97:undefined reference to `selftests::reset()'
collect2: error: ld returned 1 exit status
selftest.o shouldn't be compiled and linked when $development is false.
With this patch, in release mode, GDBserver doesn't nothing with option
--selftest,
$ ./gdbserver --selftest=foo
Selftests are not available in a non-development build.
$ ./gdbserver --selftest
Selftests are not available in a non-development build.
gdb/gdbserver:
2018-01-08 Yao Qi <yao.qi@linaro.org>
Simon Marchi <simon.marchi@ericsson.com>
* Makefile.in (OBS): Remove selftest.o.
* configure.ac: Set srv_selftest_objs if $development is true.
(GDBSERVER_DEPFILES): Append $srv_selftest_objs.
* configure: Re-generated.
* server.c (captured_main): Wrap variable selftest_filter with
GDB_SELF_TEST.
gdb/testsuite:
2018-01-08 Simon Marchi <simon.marchi@ericsson.com>
* gdb.server/unittest.exp: Match the output in non-development
mode.
This avoid having to manually free the return value.
gdb/gdbserver/ChangeLog:
* server.c (parse_debug_format_options): Return std::string.
(handle_monitor_command, captured_main): Adjust.
At https://sourceware.org/bugzilla/show_bug.cgi?id=18653#c7, Andrew
reports that the fix for PR gdb/18653 made GDB useless if you preload
libSegFault.so, because GDB internal-errors on startup:
$ LD_PRELOAD=libSegFault.so gdb
src/gdb/common/signals-state-save-restore.c:64: internal-error: unexpected signal handler
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Aborted (core dumped)
$
The internal error comes from the code saving the signal dispositions
inherited from gdb's parent:
(top-gdb) bt
#0 0x000000000056b001 in internal_error(char const*, int, char const*, ...) (file=0xaf5f38 "src/gdb/common/signals-state-save-restore.c", line=64, fmt=0xaf5f18 "unexpected signal handler") at src/gdb/common/errors.c:54
#1 0x00000000005752c9 in save_original_signals_state() () at src/gdb/common/signals-state-save-restore.c:64
#2 0x00000000007425de in captured_main_1(captured_main_args*) (context=0x7fffffffd860)
at src/gdb/main.c:509
#3 0x0000000000743622 in captured_main(void*) (data=0x7fffffffd860) at src/gdb/main.c:1145
During symbol reading, cannot get low and high bounds for subprogram DIE at 24065.
#4 0x00000000007436f9 in gdb_main(captured_main_args*) (args=0x7fffffffd860) at src/gdb/main.c:1171
#5 0x0000000000413acd in main(int, char**) (argc=1, argv=0x7fffffffd968) at src/gdb/gdb.c:32
This commit downgrades the internal error to a warning. You'll get
instead:
~~~
$ LD_PRELOAD=libSegFault.so gdb
warning: Found custom handler for signal 11 (Segmentation fault) preinstalled.
Some signal dispositions inherited from the environment (SIG_DFL/SIG_IGN)
won't be propagated to spawned programs.
GNU gdb (GDB) 8.0.50.20171213-git
Copyright (C) 2017 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-pc-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
(gdb)
~~~
This also moves the location where save_original_signals_state is
called a bit further below (to after option processing), so that "-q"
disables the warning:
~~~
$ LD_PRELOAD=libSegFault.so gdb -q
(gdb)
~~~
New testcase included.
gdb/ChangeLog:
2018-01-05 Pedro Alves <palves@redhat.com>
PR gdb/18653
* common/signals-state-save-restore.c
(save_original_signals_state): New parameter 'quiet'. Warn if we
find a custom handler preinstalled, instead of internal erroring.
But only warn if !quiet.
* common/signals-state-save-restore.h
(save_original_signals_state): New parameter 'quiet'.
* main.c (captured_main_1): Move save_original_signals_state call
after option handling, and pass QUIET.
gdb/gdbserver/ChangeLog:
2018-01-05 Pedro Alves <palves@redhat.com>
PR gdb/18653
* server.c (captured_main): Pass quiet=false to
save_original_signals_state.
gdb/testsuite/ChangeLog:
2018-01-05 Pedro Alves <palves@redhat.com>
PR gdb/18653
* gdb.base/libsegfault.exp: New.
gdb/ChangeLog:
* top.c (print_gdb_version): Update Copyright year in version
message.
gdb/gdbserver/ChangeLog:
* gdbreplay.c (gdbreplay_version): Update copyright year in
version message.
* server.c (gdbserver_version): Likewise.
This patch makes the syscalls_to_catch field of process_info an
std::vector<int>. The process_info structure must now be
newed/deleted.
In handle_extended_wait, the code that handles exec events destroys the
existing process_info and creates a new one. It moves the content of
syscalls_to_catch from the old to the new vector. I used std::move for
that (through an intermediary variable), which should have the same
behavior as the old code.
gdb/gdbserver/ChangeLog:
* inferiors.h (struct process_info): Add constructor, initialize
fields..
<syscalls_to_catch>: Change type to std::vector<int>.
* inferiors.c (add_process): Allocate process_info with new.
(remove_process): Free process_info with delete.
* linux-low.c (handle_extended_wait): Adjust.
(gdb_catching_syscalls_p, gdb_catch_this_syscall_p): Adjust.
* server.c (handle_general_set): Adjust.
Change find_inferior with find_thread. Since we can now pass arguments
directly instead of through a void pointer, we don't need the
visit_actioned_threads_data structure anymore.
gdb/gdbserver/ChangeLog:
* server.c (struct visit_actioned_threads_data): Remove.
(visit_actioned_threads): Change prototype to take arguments
directly.
(resume): Use find_thread instead of find_inferior.
Replace one with find_thread, the other with for_each_thread.
gdb/gdbserver/ChangeLog:
* server.c (queue_stop_reply_callback): Change prototype, return
void.
(find_status_pending_thread_callback): Remove.
(handle_status): Replace find_inferior with find_thread and
for_each_thread.
