As uintptr_t is used stdint.h must be included on all architectures.
2013-08-28 Will Newton <will.newton@linaro.org>
* common/linux-ptrace.c: Include stdint.h unconditionally.
This stops another target from installing a
target_ops->deprecated_xfer_memory method.
Tested on native MinGW.
gdb/
2013-08-27 Pedro Alves <palves@redhat.com>
* windows-nat.c (windows_xfer_memory): Adjust prototype to follow
xfer_partial's interface. Return TARGET_XFER_E_IO on error.
(windows_xfer_partial): Defer TARGET_OBJECT_MEMORY handling to
windows_xfer_memory directly.
(init_windows_ops): Don't install a deprecated_xfer_memory method.
darwin_xfer_partial already handles TARGET_OBJECT_MEMORY, so this
method is not necessary.
gdb/
2013-08-27 Pedro Alves <palves@redhat.com>
* darwin-nat.c (darwin_xfer_memory): Delete.
(_initialize_darwin_inferior): Don't install a
deprecated_xfer_memory method.
This is the patch to add new option '--skip-unavailable' to MI
commands '-stack-list-{locals, arguments, variables}'. This patch
extends list_args_or_locals to add a new parameter 'skip_unavailable',
and don't list locals or arguments if values are unavailable and
'skip_unavailable' is true.
This is inspecting a trace frame (tfind mode), where only a few
locals have been collected.
-stack-list-locals, no switch vs new switch:
-stack-list-locals --simple-values
^done,locals=[{name="array",type="unsigned char [2]"},{name="i",type="int",value="<unavailable>"}]
-stack-list-locals --skip-unavailable --simple-values
^done,locals=[{name="array",type="unsigned char [2]"}]
-stack-list-arguments, no switch vs new switch:
-stack-list-arguments --simple-values
^done,stack-args=[frame={level="0",args=[{name="j",type="int",value="4"},{name="s",type="char *",value="<unavailable>"}]},frame={level="1",args=[]}]
-stack-list-arguments --skip-unavailable --simple-values
^done,stack-args=[frame={level="0",args=[{name="j",type="int",value="4"}]},frame={level="1",args=[]}]
-stack-list-variables, no switch vs new switch:
-stack-list-variables --simple-values
^done,variables=[{name="j",arg="1",type="int",value="4"},{name="s",arg="1",type="char *",value="<unavailable>"},{name="array",type="unsigned char [2]"},{name="i",type="int",value="<unavailable>"}]
-stack-list-variables --skip-unavailable --simple-values
^done,variables=[{name="j",arg="1",type="int",value="4"},{name="array",type="unsigned char [2]"}]
tests are added to test these new options.
gdb:
2013-08-27 Pedro Alves <pedro@codesourcery.com>
Yao Qi <yao@codesourcery.com>
* mi/mi-cmd-stack.c (list_args_or_locals): Adjust prototype.
(parse_no_frames_option): Remove.
(mi_cmd_stack_list_locals): Handle --skip-unavailable.
(mi_cmd_stack_list_args): Adjust.
(mi_cmd_stack_list_variables): Handle --skip-unavailable.
(list_arg_or_local): Add new parameter 'skip_unavailable'. Return
early if SKIP_UNAVAILABLE is true and ARG->val is unavailable.
Caller update.
(list_args_or_locals): New parameter 'skip_unavailable'.
Handle it.
* valprint.c (scalar_type_p): Rename to ...
(val_print_scalar_type_p): ... this. Make extern.
(val_print, value_check_printable): Adjust.
* valprint.h (val_print_scalar_type_p): Declare.
* value.c (value_entirely_unavailable): New function.
* value.h (value_entirely_unavailable): Declare.
* NEWS: Mention the new option "--skip-unavailable" to MI
commands '-stack-list-locals', '-stack-list-arguments' and
'-stack-list-variables'.
gdb/doc:
2013-08-27 Pedro Alves <pedro@codesourcery.com>
Yao Qi <yao@codesourcery.com>
* gdb.texinfo (GDB/MI Stack Manipulation) <-stack-list-locals>:
Document new --skip-unavailable option.
<-stack-list-variables>: Document new --skip-unavailable option.
gdb/testsuite:
2013-08-27 Yao Qi <yao@codesourcery.com>
* gdb.trace/entry-values.exp: Test unavailable entry value is
not shown when option '--skip-unavailable' is specified.
* gdb.trace/mi-trace-unavailable.exp (test_trace_unavailable):
Add tests for new option '--skip-unavailable'.
This patch is to add a new function mi_getopt_allow_unknown, which
returns -1 silently (without throwing error) when unknown option is
met, and use this function to parse options for command
'-stack-list-arguments'.
gdb/
* mi/mi-cmd-stack.c (parse_no_frames_option): Remove.
(mi_cmd_stack_list_args): Use mi_getopt_silent to handle
options.
* mi/mi-getopt.c (mi_getopt): Remove.
(mi_getopt_1): Renamed from mi_getopt. Add one parameter
'error_on_unknown'.
(mi_getopt): Call mi_getopt_1.
(mi_getopt_silent): New.
* mi/mi-getopt.h (mi_getopt_silent): Declare.
* symmisc.c (maintenance_print_objfiles): Argument is now an optional
regexp of objfiles to print.
(_initialize_symmisc): Update doc string for "mt print objfiles".
doc/
* gdb.texinfo (Maintenance Commands): "maint print objfiles" now takes
an optional regexp.
* gdb.trace/entry-values.c (end): New
(main): Call end.
* gdb.trace/entry-values.exp: Load trace-support.exp. Set
tracepoint and collect data. Test entry value is unavailable.
(dump_msymbols, dump_objfile): Ditto.
(maintenance_info_symtabs): Mark as dont_repeat.
(_initialize_symmisc): Improve doc string for "mt info symtabs".
'ret' is used to hold the return of target_read, and pass it on. Both
target_read and target_read_live_memory return LONGEST.
gdb/
2013-08-23 Pedro Alves <palves@redhat.com>
* target.c (target_read_live_memory): Change type of 'ret' local
to LONGEST.
There's no need for deprecated_xfer_memory nowadays. Memory access
goes through target_xfer_partial/TARGET_OBJECT_MEMORY, etc. In fact,
the remote target already handles that, and is deferring to the same
helpers the deprecated_xfer_memory hook is. Basically, only a few
adjustments to make these helper routines's interfaces closer to
target_xfer_partial's were necessary.
Tested on x86_64 Fedora 17 w/ gdbserver.
gdb/
2013-08-23 Pedro Alves <palves@redhat.com>
* remote.c (remote_write_bytes_aux, remote_write_bytes)
(remote_read_bytes): Change return type to LONGEST, and adjust to
return a target_xfer_error on error.
(remote_xfer_memory): Delete.
(remote_flash_write): Change type of 'ret' local to LONGEST.
(remote_xfer_partial, remote_xfer_partial): Adjust.
(init_remote_ops): Don't install a deprecated_xfer_memory hook.
PR gdb/15501
* breakpoint.c (enable_command, disable_command): Iterate over
all specified breakpoint locations.
2013-07-12 Muhammad Waqas <mwaqas@codesourccery.com>
PR gdb/15501
* gdb.base/ena-dis-br.exp: Add test to verify
enable/disable commands work correctly with
multiple arguments that include multiple locations.
This time, it passes all the tests and comes with a nearly complete
XML file (plus a script that can nearly regenerate the XML file).
(I elected to leave out __ARM_NR_cmpxchg, since it has dire warnings
to the effect that the only pieces of code that should be aware of it
are the implementation and the __kuser_cmpxchg code in entry-armv.S.)
gdb/
2013-08-14 Samuel Bronson <naesten@gmail.com>
ARM Linux support for `catch syscall'.
* syscalls/arm-linux.py: New file.
* syscalls/arm-linux.xml: Likewise.
* arm-linux-tdep.c (arm_linux_get_syscall_number): New function.
(arm_linux_init_abi): Register the new function and syscall xml file.
* data-directory/Makefile.in: Install the new syscall xml file.
* NEWS: Brag about this.
gdb/testsuite/
2013-08-14 Samuel Bronson <naesten@gmail.com>
ARM Linux support for `catch syscall'.
* gdb.base/catch-syscall.exp: Test this on ARM now.
(fill_all_syscalls_numbers): ARM has close/chroot on 6/61, too.
This fixes dwz.exp on 32-bit targets. It does so by introducing a new
"default" setting for the address size in the DWARF assembler.
Built and regtested on x86-64 Fedora 18.
I also ran the gdb.dwarf2 tests on an x86 machine (gcc45).
* lib/dwarf.exp (cu, tu): Handle addr_size of "default". Change
default addr_size.
* lib/gdb.exp (is_64_target): New gdb_caching_proc.
I noticed that skip_btrace_tests is a classic "caching proc" that I
missed when I added gdb_caching_proc. This patch converts it.
Built and regtested on x86-64 Fedora 18.
* lib/gdb.exp (skip_btrace_tests): Use gdb_caching_proc and
standard_temp_file.
This fixes parts of gdb.arch to be parallel-safe.
I only changed the bits I could test on this machine.
I don't have access to many of the machines needed to fully switch
gdb.arch; but I am happy to provide advice to others attempting this.
Or, I can send an untested patch to convert it all.
Tested on x86-64 Fedora 18.
* gdb.arch/amd64-byte.exp: Use standard_testfile,
clean_restart.
* gdb.arch/amd64-disp-step.exp: Use standard_testfile.
* gdb.arch/amd64-dword.exp: Use standard_testfile,
clean_restart.
* gdb.arch/amd64-entry-value-param.exp: Use standard_testfile.
* gdb.arch/amd64-entry-value.exp: Use standard_testfile.
* gdb.arch/amd64-prologue-xmm.exp: Use standard_testfile.
* gdb.arch/amd64-word.exp: Use standard_testfile,
clean_restart.
* gdb.arch/i386-avx.exp: Use standard_testfile, clean_restart.
* gdb.arch/i386-byte.exp: Use standard_testfile, clean_restart.
* gdb.arch/i386-disp-step.exp: Use standard_testfile.
* gdb.arch/i386-dr3-watch.exp: Use standard_testfile.
* gdb.arch/i386-permbkpt.exp: Use standard_testfile, clean_restart.
* gdb.arch/i386-signal.exp: Use standard_testfile.
* gdb.arch/i386-size-overlap.exp: Use standard_testfile, clean_restart.
* gdb.arch/i386-sse.exp: Use standard_testfile, clean_restart.
* gdb.arch/i386-unwind.exp: Use standard_testfile.
* gdb.arch/i386-word.exp: Use standard_testfile, clean_restart.
This fixes gdb.python to be parallel-safe, mostly by changing it to
use gdb_remote_download.
Tested on x86-64 Fedora 18.
* gdb.python/py-error.exp: Use gdb_remote_download.
* gdb.python/py-mi.exp: Use gdb_remote_download.
* gdb.python/py-objfile-script.exp: Use standard_output_file.
* gdb.python/py-prettyprint.exp: Use gdb_remote_download.
(run_lang_tests): Likewise.
* gdb.python/py-section-script.c: Use SCRIPT_FILE rather than
filename.
* gdb.python/py-section-script.exp: Set SCRIPT_FILE when
compiling. Use gdb_remote_download. Update some tests.
* gdb.python/py-strfns.exp (test_strfns_core_file): Use
standard_output_file.
* gdb.python/py-typeprint.exp: Use gdb_remote_download.
* gdb.python/py-frame-args.exp: Use gdb_remote_download.
* gdb.python/py-framefilter-mi.exp: Use gdb_remote_download.
* gdb.python/py-framefilter.exp: Use gdb_remote_download,
standard_output_file.
In an earlier patch I forgot to change the caching proc in cell.exp to
use standard_temp_file. This fixes the oversight.
Tested on x86-64 Fedora 18.
* lib/cell.exp (skip_cell_tests): Use standard_temp_file.
This finishes making gdb.dwarf2 parallel-safe.
To do this, this patch introduces a new gdb_remote_download proc, that
works somewhat differently in the one specific case where it matters:
for a copy to "host", if no destination was given, and the host is not
actually remote, then standard_output_file is used. In parallel mode
this guarantees that the resulting file will end up in a parallel-safe
location.
Tested on x86-64 Fedora 18.
* gdb.dwarf2/dw2-basic.exp: Use gdb_remote_download.
* gdb.dwarf2/dw2-compressed.exp: Use gdb_remote_download.
* gdb.dwarf2/dw2-intercu.exp: Use gdb_remote_download.
* gdb.dwarf2/dw2-intermix.exp: Use gdb_remote_download.
* gdb.dwarf2/dw2-producer.exp: Use gdb_remote_download.
* gdb.dwarf2/mac-fileno.exp: Use gdb_remote_download.
* lib/gdb.exp (gdb_remote_download): New proc.
This fixes a few gdb.dwarf2 tests to be more parallel-safe. This
mostly amounts to changing them to write their files into the
directory designated by standard_output_file.
Built and regtested on x86-64 Fedora 18.
* gdb.dwarf2/clztest.exp: Use standard_testfile.
* gdb.dwarf2/dw2-minsym-in-cu.exp: Use standard_testfile.
* gdb.dwarf2/fission-base.S: Remove directory from
DW_AT_GNU_dwo_name.
* gdb.dwarf2/fission-base.exp: Use build_executable. Set
debug-file-directory.
* gdb.dwarf2/fission-reread.S: Remove directory from
DW_AT_GNU_dwo_name.
* gdb.dwarf2/fission-reread.exp: Use build_executable. Set
debug-file-directory.
In entry-values.exp, we have a test where the entry value of 'j' is
unavailable, so it is expected that printing j@entry yields
"<unavailable>". However, the actual output is:
(gdb) frame
#0 0x0000000000400540 in foo (i=0, i@entry=2, j=2, j@entry=<error reading variable: Cannot access memory at address 0x6009e8>)
The error is thrown here:
#0 throw_it (reason=RETURN_ERROR, error=MEMORY_ERROR, fmt=0x8cd550 "Cannot access memory at address %s", ap=0x7fffffffc8e8) at ../../src/gdb/exceptions.c:373
#1 0x00000000005e2f9c in throw_error (error=MEMORY_ERROR, fmt=0x8cd550 "Cannot access memory at address %s") at ../../src/gdb/exceptions.c:422
#2 0x0000000000673a5f in memory_error (status=5, memaddr=6293992) at ../../src/gdb/corefile.c:204
#3 0x0000000000673aea in read_memory (memaddr=6293992, myaddr=0x7fffffffca60 "\200\316\377\377\377\177", len=4) at ../../src/gdb/corefile.c:223
#4 0x00000000006784d1 in dwarf_expr_read_mem (baton=0x7fffffffcd50, buf=0x7fffffffca60 "\200\316\377\377\377\177", addr=6293992, len=4) at ../../src/gdb/dwarf2loc.c:334
#5 0x000000000067645e in execute_stack_op (ctx=0x1409480, op_ptr=0x7fffffffce87 "\237<\005@", op_end=0x7fffffffce88 "<\005@") at ../../src/gdb/dwarf2expr.c:1045
#6 0x0000000000674e29 in dwarf_expr_eval (ctx=0x1409480, addr=0x7fffffffce80 "\003\350\t`", len=8) at ../../src/gdb/dwarf2expr.c:364
#7 0x000000000067c5b2 in dwarf2_evaluate_loc_desc_full (type=0x10876d0, frame=0xd8ecc0, data=0x7fffffffce80 "\003\350\t`", size=8, per_cu=0xf24c40, byte_offset=0)
at ../../src/gdb/dwarf2loc.c:2236
#8 0x000000000067cc65 in dwarf2_evaluate_loc_desc (type=0x10876d0, frame=0xd8ecc0, data=0x7fffffffce80 "\003\350\t`", size=8, per_cu=0xf24c40)
at ../../src/gdb/dwarf2loc.c:2407
#9 0x000000000067a5d4 in dwarf_entry_parameter_to_value (parameter=0x13a7960, deref_size=18446744073709551615, type=0x10876d0, caller_frame=0xd8ecc0, per_cu=0xf24c40)
at ../../src/gdb/dwarf2loc.c:1160
#10 0x000000000067a962 in value_of_dwarf_reg_entry (type=0x10876d0, frame=0xd8de70, kind=CALL_SITE_PARAMETER_DWARF_REG, kind_u=...) at ../../src/gdb/dwarf2loc.c:1310
#11 0x000000000067aaca in value_of_dwarf_block_entry (type=0x10876d0, frame=0xd8de70, block=0xf1c2d4 "Q", block_len=1) at ../../src/gdb/dwarf2loc.c:1363
#12 0x000000000067e7c9 in locexpr_read_variable_at_entry (symbol=0x13a7540, frame=0xd8de70) at ../../src/gdb/dwarf2loc.c:3326
#13 0x00000000005daab6 in read_frame_arg (sym=0x13a7540, frame=0xd8de70, argp=0x7fffffffd0e0, entryargp=0x7fffffffd100) at ../../src/gdb/stack.c:362
#14 0x00000000005db384 in print_frame_args (func=0x13a7470, frame=0xd8de70, num=-1, stream=0xea3890) at ../../src/gdb/stack.c:669
#15 0x00000000005dc338 in print_frame (frame=0xd8de70, print_level=1, print_what=SRC_AND_LOC, print_args=1, sal=...) at ../../src/gdb/stack.c:1199
#16 0x00000000005db8ee in print_frame_info (frame=0xd8de70, print_level=1, print_what=SRC_AND_LOC, print_args=1) at ../../src/gdb/stack.c:851
#17 0x00000000005da2bb in print_stack_frame (frame=0xd8de70, print_level=1, print_what=SRC_AND_LOC) at ../../src/gdb/stack.c:169
#18 0x00000000005de236 in frame_command (level_exp=0x0, from_tty=1) at ../../src/gdb/stack.c:2265
dwarf2_evaluate_loc_desc_full (frame #7) knows to handle
NOT_AVAILABLE_ERROR errors, but read_memory always throws
a generic error.
Presently, only the value machinery knows to handle unavailable
memory. We need to push the awareness down to the target_xfer layer,
making it return a finer grained error indication. We can only return
a generic -1 nowadays, which leaves the upper layers with no clue on
why the xfer failed. Use target_xfer_partial directly, rather than
propagating the error through target_read_memory so as to get a better
address to display in the error message.
(target_read_memory & friends build on top of target_read (thus the
target_xfer machinery), but turn all errors to EIO, an errno value. I
think this is a mistake, and we'd better convert all these to return a
target_xfer_error too, but that can be done separately. I looked
around a bit over memory_error calls, and the need to handle random
errno values, other than the EIOs gdb itself hardcodes, probably comes
(only) from deprecated_xfer_memory, which uses errno for error
indication, but I didn't look exhaustively. We should really get rid
of deprecated_xfer_memory and of passing down errno values as error
indication in target_read & friends methods).
Tested on x86_64 Fedora 17, native and gdbserver. Fixes the test in
the PR, which will be added to the testsuite later.
gdb/
2013-08-22 Pedro Alves <palves@redhat.com>
PR gdb/15871
* corefile.c (target_xfer_memory_error): New function.
(memory_error): Defer EIO to target_memory_error.
(read_memory): Use target_xfer_partial, and handle finer-grained
target xfer errors.
* target.c (target_xfer_error_to_string): New function.
(memory_xfer_partial_1): If memory is known to be
unavailable, return TARGET_XFER_E_UNAVAILABLE instead of -1.
(target_xfer_partial): Make extern.
* target.h (enum target_xfer_error): New enum.
(target_xfer_error_to_string): Declare function.
(target_xfer_partial): Declare function.
(struct target_ops) <xfer_partial>: Adjust describing comment.
(pending_macros): Ditto.
(get_macro_table): New function.
(buildsym_init): Initialize subfile_stack.
* coffread.c (type_vector,type_vector_length): Moved here from
buildsym.h.
(INITIAL_TYPE_VECTOR_LENGTH): Ditto.
(coff_symtab_read): Use it.
* dbxread.c (read_ofile_symtab): Delete init of subfile_stack.
* dwarf2read.c (macro_start_file): Replace uses of pending_macros
with call to get_macro_table.
* stabsread.c (type_vector,type_vector_length): Moved here from
buildsym.h.
(INITIAL_TYPE_VECTOR_LENGTH): Ditto.
* buildsym.h (get_macro_table): Declare.
This fixes PR python/15816.
The bug here is that python-selftest.exp can fail:
No symbol "RETURN_MASK_ALL" in current context.
RETURN_MASK_ALL is a macro, so if macros do not end up in the
debuginfo (very typical) then the test fails.
It seemed simplest to me to simply turn the RETURN_MASK_ defines into
enum constants. This way they end up in the debuginfo and all is
well.
PR python/15816:
* exceptions.h (return_mask): Now an enum.
(RETURN_MASK_QUIT, RETURN_MASK_ERROR, RETURN_MASK_ALL): Now
enum constants.
Built and regtested on x86-64 Fedora 18.
This moves the "gdbarch" field from the objfile into the BFD.
This field's value is derived from the BFD and is immutable over the
lifetime of the BFD. This makes it a reasonable candidate for pushing
into the per-BFD object.
This is part of the long-term objfile splitting project. In the long
run I think this patch will make it simpler to moves types from the
objfile to the per-BFD object; but the patch makes sense as a minor
cleanup by itself.
Built and regtested on x86-64 Fedora 18.
* cp-namespace.c (cp_lookup_symbol_imports_or_template): Use
get_objfile_arch.
* elfread.c (elf_rel_plt_read, elf_gnu_ifunc_record_cache)
(elf_gnu_ifunc_resolve_by_got): Use get_objfile_arch.
* jit.c (jit_object_close_impl): Update.
* jv-lang.c (get_dynamics_objfile): Update.
* linespec.c (add_minsym): Use get_dynamics_objfile.
* objfiles.c (get_objfile_bfd_data): Initialize 'gdbarch' field.
(allocate_objfile): Don't initialize 'gdbarch' field.
(get_objfile_arch): Update.
* objfiles.h (struct objfile_per_bfd_storage) <gdbarch>: New field,
moved from...
(struct objfile) <gdbarch>: ... here. Remove.
* stap-probe.c (stap_can_evaluate_probe_arguments): Use
get_objfile_arch.
* symfile.c (init_entry_point_info): Use get_objfile_arch.
for IBM long double nan and inf.
(floatformat_is_negative, floatformat_classify,
floatformat_mantissa): Similarly.
(floatformat_ieee_single, floatformat_ieee_double,
floatformat_ieee_quad, floatformat_arm_ext,
floatformat_ia64_spill): Delete unused vars.
(_initialize_doublest): Delete unused function.
* gdbtypes.c (floatformats_ibm_long_double): Use new big- and
little-endian variants of floatformat_ibm_long_double.
* Makefile.in (SFILES): Remove common/target-common.c and
add target/waitstatus.c.
(HFILES_NO_SRCDIR): Remove common/target-common.h and add
target/resume.h, target/wait.h and target/waitstatus.h.
(COMMON_OBS): Remove target-common.o and add
waitstatus.o.
(target-common.o): Remove.
(waitstatus.o): New target object file.
* common/target-common.c: Move contents to
target/waitstatus.c and remove.
* common/target-common.h: Move contents to other files and
remove.
(enum resume_kind: Move to target/resume.h.
(TARGET_WNOHANG): Move to target/wait.h.
(enum target_waitkind): Move to target/waitstatus.h.
(struct target_waitstatus): Likewise.
* target.h: Do not include target-common.h and
include target/resume.h, target/wait.h and
target/waitstatus.h.
* target/resume.h: New file.
* target/wait.h: New file.
* target/waitstatus.h: New file.
* target/waitstatus.c: New file.
gdb/gdbserver/
* Makefile.in (INCLUDE_CFLAGS): Include -I$(srcdir)/../.
(SFILES): Remove $(srcdir)/common/target-common.c and
add $(srcdir)/target/waitstatus.c.
(OBS): Remove target-common.o and add waitstatus.o.
(server_h): Remove $(srcdir)/../common/target-common.h and
add $(srcdir)/../target/resume.h, $(srcdir)/../target/wait.h
and $(srcdir)/../target/waitstatus.h.
(target-common.o): Remove.
(waitstatus.o): New target object file.
* target.h: Do not include target-common.h and
include target/resume.h, target/wait.h and
target/waitstatus.h.
In http://sourceware.org/ml/gdb-patches/2013-08/msg00174.html , the
issue of child signal handling around ptrace option support discovery
being different between GDB and GDBserver came up.
I recalled adding these block_child_signals calls, and the "We don't
want those ptrace calls to be interrupted" comment, but not exactly
why. So I looked into it. My first guess is that I got confused.
The patch that added this
<http://sourceware.org/ml/gdb-patches/2009-04/msg00125.html> rewrote
the linux native async support completely, and the old async support
code had the SIGCHLD handler itself do waitpid, so in places that we'd
want a blocking waitpid, we'd have to have the signal handler blocked.
That was probably the mindset I had at the time. Anyway, whatever the
case, looks like I was wrong on the need for this blocking.
Given GDBserver doesn't block like this, I investigated why this is
currently needed on GDB but not on GDBserver.
I removed the block_child_signals (and restore) calls, and hacked
linux-nat.c to call linux_test_for_tracefork in a loop, like:
@@ -534,7 +534,10 @@ static int
linux_supports_tracefork (int pid)
{
if (linux_supports_tracefork_flag == -1)
- linux_test_for_tracefork (pid);
+ {
+ while (1)
+ linux_test_for_tracefork (pid);
+ }
return linux_supports_tracefork_flag;
}
Running the resulting GDB, I then saw bad things happening.
Specifically, I'd end up with a bunch of zombies, and eventually, the
machine would refuse to spawn new processes, claming insufficient
resources.
The issue is that linux_test_for_tracefork test forks, and has the
child fork again. If we don't block SIGCHLD on entry to the function,
the children will inherit SIGCHLD's action/disposition (meaning,
SIGCHLD will be unblocked in the child). When the first child forks
again a second child, and that child exits, the first child gets a
SIGCHLD. Now, when we try to wrap up for the whole options test, we
kill the first child, and collect the waitstatus. Here, when SIGCHLD
isn't blocked, GDB will first see the child reporting a stop with
SIGCHLD. gdbserver's ptrace options test does a PTRACE_KILL loop at
the end, which catches the SIGCHLD, and retries the kill. The GDB
version did not do that. So the GDB version would proceed, leaving
the child zombie (until GDB exists), as nothing collected its final
waitstatus.
So this patch makes the GDB version of linux_test_for_tracefork do the
exact same as the GDBserver version, removes all this unnecessary
blocking throughout, and adds a couple comments at places that do need
it -- namely: places where we'll use sleep with sigsuspend; and
linux_async_pipe, as that destroys the pipe the signal handler
touches.
Tested on x86_64 Fedora 17, sync and async.
gdb/
2013-08-19 Pedro Alves <palves@redhat.com>
* linux-nat.c (linux_test_for_tracefork)
(linux_test_for_tracesysgood, linux_child_follow_fork)
(lin_lwp_attach_lwp, linux_nat_resume): Don't block child signals.
(linux_nat_wait_1): Extend comment.
(linux_async_pipe): Add comment.
This moves a few static variables from thread-info functions into
remote_state. Pedro said on irc that these functions implement the
ancient thread-discovery method and that he wouldn't be surprised if
they had rotted; nevertheless it seems safer to me to make them
explicitly per-remote.
This necessitated moving a couple of macros and a typedef earlier in
the file.
* remote.c (struct remote_state) <echo_nextthread, nextthread,
resultthreadlist>: New fields.
(OPAQUETHREADBYTES, threadref, MAXTHREADLISTRESULTS): Move earlier.
(remote_get_threadlist, remote_threadlist_iterator): Use
new fields. Remove static variables.
Will Newton
Jan Kratochvil
Yao Qi
Doug Evans
Pedro Alves
Ulrich Weigand
Pierre Muller
Muhammad Waqas
Luis Machado
Sergio Durigan Junior
Tom Tromey
Alan Modra
Kevin Buettner
Muhammad Bilal