On ppc-lynx178, resuming the execution of a program after hitting
a breakpoint sometimes triggers a spurious SIG61 event:
(gdb) cont
Continuing.
Program received signal SIG61, Real-time event 61.
[Switching to Thread 39]
0x10002324 in a_test.task1 (<_task>=0x3ffff774) at a_test.adb:30
30 select -- Task 1
From this point on, continuing again lets the signal kill the program.
Using "signal 0" or configuring GDB to discard the signal does not
help either, as the program immediately reports the same signal again.
What happens is the following:
- GDB sends a single-step order to gdbserver: $vCont;s:31
This tells GDBserver to do a step using thread 0x31=49.
GDBserver does the step, and thread 49 receives the SIGTRAP
indicating that the step has finished.
- GDB then sends a "continue", but this time does not specify
which thread to continue: $vCont;c
GDBserver uses an arbitrary thread's ptid to resume the program's
execution (the current_inferior's ptid was chosen for that).
See lynx-low.c:lynx_resume:
if (ptid_equal (ptid, minus_one_ptid))
ptid = thread_to_gdb_id (current_inferior);
So far on all LynxOS platforms, this has been good enough. But
not so on LynxOS 178. If the ptid used to resume the execution
is not the same as the thread that did the step, we get the weird
signal.
This patch fixes the problem by saving the ptid of the thread
that last caused an event, received during a call to waitpid.
The ptid is saved in per-process private data.
gdb/gdbserver/ChangeLog:
* lynx-low.c (struct process_info_private): New type.
(lynx_add_process): New function.
(lynx_create_inferior, lynx_attach): Replace calls to
add_process by calls to lynx_add_process.
(lynx_resume): If PTID is null, then try using
current_process()->private->last_wait_event_ptid.
Add comments.
(lynx_clear_inferiors): Delete. The contents of that function
has been inlined in lynx_mourn;
(lynx_wait_1): Save the ptid in the process's private data.
(lynx_mourn): Free the process' private data. Replace call
to lynx_clear_inferiors by call to clear_inferiors.
PT_DATA_ADDR and PT_TEXT_END_ADDR. Update comments.
(linux_read_offsets): Remove PT_TEXT_ADDR, PT_DATA_ADDR and
PT_TEXT_END_ADDR guards. Update comments.
(linux_target_op) <read_offsets>: Conditionally define to
linux_read_offsets if the target is UCLIBC and if it defines
PT_TEXT_ADDR, PT_DATA_ADDR and PT_TEXT_END_ADDR.
* tracepoint.c (cmd_qtinit): Call 'stop_tracing'.
2013-05-03 Hafiz Abid Qadeer <abidh@codesourcery.com>
* status-stop.exp (test_tstart_tstart): Check for error
returned by the second 'tstart' command.
A small cleanup. 'struct lwp_info'::thread_known is only useful for
thread-db.c.
gdbserver/
2013-04-16 Pedro Alves <palves@redhat.com>
* linux-low.h (struct lwp_info) <thread_known>: Move under
the USE_THREAD_DB #ifdef.
The previous patches are still not sufficient to build gdbserver with
our copy of thread_db.h.
../../../src/gdb/gdbserver/thread-db.c: In function ‘find_one_thread’:
../../../src/gdb/gdbserver/thread-db.c:316:6: error: ‘struct lwp_info’ has no member named ‘th’
../../../src/gdb/gdbserver/thread-db.c: In function ‘attach_thread’:
../../../src/gdb/gdbserver/thread-db.c:341:6: error: ‘struct lwp_info’ has no member named ‘th’
../../../src/gdb/gdbserver/thread-db.c: In function ‘thread_db_get_tls_address’:
../../../src/gdb/gdbserver/thread-db.c:514:47: error: ‘struct lwp_info’ has no member named ‘th’
make: *** [thread-db.o] Error 1
First, linux-low.h is including <thread_db.h> directly instead of our
gdb_thread_db.h, although thread-db.c includes the latter. Then the
'th' field of struct lwp_info is only defined if HAVE_THREAD_DB_H is
defined, which is not true if we're using our replacement copy of
thread_db.h. We have a USE_THREAD_DB symbol defined if we're building
thread-db.c that's ideal for this, however, it's currently only
defined when compiling linux-low.c (through a Makefile rule). The
patch makes it defined when compiling any file.
gdb/gdbserver/
2013-04-16 Pedro Alves <palves@redhat.com>
* Makefile.in (INTERNAL_CFLAGS): Add @USE_THREAD_DB@.
(linux-low.o): Delete rule.
* linux-low.h: Always include "gdb_thread_db.h" instead of
conditionally including thread_db.h.
(struct lwp_info) <th>: Guard with #ifdef USE_THREAD_DB instead of
HAVE_THREAD_DB_H.
Oleg Nesterov told me that the Linux kernel copies the parent's ptrace
options to fork/clone children, so there's no need for GDB to do that
manually.
I was actually a bit surprised, since I thought the ptracer had to
always set the ptrace options itself, and GDB is indeed calling
PTRACE_SETOPTIONS for each new fork child, if it'll stay attached.
Looking at the history of that code, I found that is was actually I
who added that set-ptrace-options-in-children bit, back in
http://sourceware.org/ml/gdb-patches/2009-05/msg00656.html. But,
honestly, I don't recall why I needed that. I think I may have just
blindly believed it was necessary.
I then looked back at the history of all the PTRACE_SETOPTIONS code we
have, and found that gdb never did copy the ptrace options before my
patch. But, when gdbserver learnt to use PTRACE_EVENT_CLONE, at
http://sourceware.org/ml/gdb-patches/2007-10/msg00547.html, it was
made to do 'ptrace (PTRACE_SETOPTIONS, new_pid, 0,
PTRACE_O_TRACECLONE)' for all new clones. Hmmm. But, GDB itself
never did that, so it can't really ever have been necessary, I
believe, otherwise GDB should have been doing it too.
(GDBserver doesn't support following forks, and so naturally doesn't
do any PTRACE_SETOPTIONS on fork children.)
So this patch removes the -I believe- unnecessary ptrace syscalls.
Tested on x86_64 Fedora 17, native/gdbserver, and on x86_64 RHEL5
native/gdbserver (Linux 2.6.18, I think a ptrace-on-utrace kernel).
No regressions.
gdb/
2013-03-22 Pedro Alves <palves@redhat.com>
* linux-nat.c (linux_child_follow_fork): Don't call
linux_enable_event_reporting.
(linux_handle_extended_wait): Don't call
linux_enable_event_reporting.
gdb/gdbserver/
2013-03-22 Pedro Alves <palves@redhat.com>
* linux-low.c (handle_extended_wait): Don't call
linux_enable_event_reporting.
This fixes the followin error when HAVE_LINUX_BTRACE is not defined:
linux-low.c:5943: error: excess elements in struct initializer
linux-low.c:5943: error: (near initialization for 'linux_target_ops')
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_target_ops) [!HAVE_LINUX_BTRACE]:
Remove extraneous NULL element.
the last matched 'V' blcok in trace frame.
gdb/gdbserver:
* tracepoint.c (traceframe_read_tsv): Look for the last matched
'V' block in trace frame.
gdb/testsuite:
* gdb.trace/tsv.exp (check_tsv): New.
(top level): Save a tfile on current trace session. Call
check_tsv on live target. Load the tfile with target tfile
and call check_tsv again.
We define the following packets:
Qbtrace:bts enable branch tracing for the current thread
returns "OK" or "Enn"
Qbtrace:off disable branch tracing for the current thread
returns "OK" or "Enn"
qXfer:btrace:read read the full branch trace data for the current thread
gdb/
* target.h (enum target_object): Add TARGET_OBJECT_BTRACE.
* remote.c: Include btrace.h.
(struct btrace_target_info): New struct.
(remote_supports_btrace): New function.
(send_Qbtrace): New function.
(remote_enable_btrace): New function.
(remote_disable_btrace): New function.
(remote_teardown_btrace): New function.
(remote_read_btrace): New function.
(init_remote_ops): Add btrace ops.
(enum <unnamed>): Add btrace packets.
(struct protocol_feature remote_protocol_features[]): Add btrace packets.
(_initialize_remote): Add packet configuration for branch tracing.
gdbserver/
* target.h (struct target_ops): Add btrace ops.
(target_supports_btrace): New macro.
(target_enable_btrace): New macro.
(target_disable_btrace): New macro.
(target_read_btrace): New macro.
* gdbthread.h (struct thread_info): Add btrace field.
* server.c: Include btrace-common.h.
(handle_btrace_general_set): New function.
(handle_btrace_enable): New function.
(handle_btrace_disable): New function.
(handle_general_set): Call handle_btrace_general_set.
(handle_qxfer_btrace): New function.
(struct qxfer qxfer_packets[]): Add btrace entry.
* inferiors.c (remove_thread): Disable btrace.
* linux-low: Include linux-btrace.h.
(linux_low_enable_btrace): New function.
(linux_low_read_btrace): New function.
(linux_target_ops): Add btrace ops.
* configure.srv (i[34567]86-*-linux*): Add linux-btrace.o.
Add srv_linux_btrace=yes.
(x86_64-*-linux*): Add linux-btrace.o.
Add srv_linux_btrace=yes.
* configure.ac: Define HAVE_LINUX_BTRACE.
* config.in: Regenerated.
* configure: Regenerated.
Hafiz Abid Qadeer <abidh@codesourcery.com>
gdb/
* NEWS: Mention set and show trace-buffer-size commands.
Mention new packet.
* target.h (struct target_ops): New method
to_set_trace_buffer_size.
(target_set_trace_buffer_size): New macro.
* target.c (update_current_target): Set up new method.
* tracepoint.c (trace_buffer_size): New global.
(start_tracing): Send it to the target.
(set_trace_buffer_size): New function.
(_initialize_tracepoint): Add new setshow for trace-buffer-size.
* remote.c (remote_set_trace_buffer_size): New function.
(_initialize_remote): Use it.
(QTBuffer:size) New remote command.
(PACKET_QTBuffer_size): New enum.
(remote_protocol_features): Add an entry for
PACKET_QTBuffer_size.
gdb/gdbserver/
* tracepoint.c (trace_buffer_size): New global.
(DEFAULT_TRACE_BUFFER_SIZE): New define.
(init_trace_buffer): Change to one-argument function. Allocate
trace buffer memory.
(handle_tracepoint_general_set): Call cmd_bigqtbuffer_size to
handle QTBuffer:size packet.
(cmd_bigqtbuffer_size): New function.
(initialize_tracepoint): Call init_trace_buffer with
DEFAULT_TRACE_BUFFER_SIZE.
* server.c (handle_query): Add QTBuffer:size in the
supported packets.
gdb/doc/
* gdb.texinfo (Starting and Stopping Trace Experiments): Document
trace-buffer-size set and show commands.
(Tracepoint Packets): Document QTBuffer:size.
(General Query Packets): Document QTBuffer:size.
gdb/testsuite/
* gdb.trace/trace-buffer-size.exp: New file.
* gdb.trace/trace-buffer-size.c: New file.
* tracepoint.c (cur_action, cur_step_action): Make them unsigned.
(cmd_qtfp): Initialize cur_action and cur_step_action 0 instead
of -1.
(cmd_qtsp): Adjust condition. Do post increment.
Set cur_action and cur_step_action back to 0.
PROBLEM:
The function linux_write_memory () in linux-low.c allocates a buffer
on the stack to hold a copy of the data to be written.
register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *)
alloca (count * sizeof (PTRACE_XFER_TYPE));
"count" is the number of bytes to be written, rounded up to the
nearest multiple of sizeof (PTRACE_XFER_TYPE) and allowing for not
being an aligned address. The function later uses
buffer[0] = ptrace (PTRACE_PEEKTEXT, pid,
(PTRACE_ARG3_TYPE) (uintptr_t) addr, 0);
The problem is that this function can be called to write zero bytes on
an aligned address, for example when receiving an X packet of length 0
(used to test if 8-bit write is supported). Under these circumstances,
count can be zero.
Since in this case, buffer[0] may never have been allocated, the stack
is corrupted and gdbserver may crash.
SOLUTION:
Writing zero bytes should always succeed. The patch below returns
successfully early if the length is zero, so avoiding the stack
corruption.
Verified on the ARC GDB 7.5.1 port.
2013-03-07 Jeremy Bennett <jeremy.bennett@embecosm.com>
PR server/15236
* linux-low.c (linux_write_memory): Return early success if LEN is
zero.
printf-like functions to avoid type related warnings on all
platforms.
(get_child_debug_event): Print dwDebugEventCode as hex since
that's how it's usually documented.
* regformats/reg-tilegx.dat (name): Change abi name to "tilegx".
* regformats/reg-tilegx32.dat: New.
gdbserver/
* Makefile.in (clean): Remove reg-tilegx.c, reg-tilegx32.c.
(reg-tilegx32.c): New rule.
* configure.srv (tilegx-*-linux*): Add reg-tilegx32.o to srv_regobj.
* linux-tile-low.c (tile_arch_setup): New function. Invoke
different register info initializer according to elf class.
(init_registers_tilgx32): New function. The tilegx32 register info
initializer.
(tile_fill_gregset): Use "uint_reg_t" to represent register size.
(tile_store_gregset): Likewise.
Addresses, as most numbers in the RSP are hex encoded, with variable
length (that just means the width isn't specified, and there's no top
cap. So they should be extracted with unpack_varlen_hex.
A couple spots in server.c are using strto(u)l, which doesn't work on
LLP64 targets.
This patch fixes it.
Tested on x86_64 Fedora 17.
2013-02-19 Pedro Alves <palves@redhat.com>
Kai Tietz <ktietz@redhat.com>
PR gdb/15161
* server.c (handle_query) <CRC check>: Use unpack_varlen_hex
instead of strtoul to extract address from packet.
(process_serial_event) <'z'>: Likewise.
The previous notes aren't being released before setting new ones.
Tested on x86_64 Fedora 17.
gdb/gdbserver/
2013-02-14 Pedro Alves <palves@redhat.com>
Plug memory leak.
* tracepoint.c (cmd_qtnotes): Free TRACING_USER_NAME,
TRACING_NOTES and TRACING_STOP_NOTE before clobbering.
An obvious use case for savestring.
Tested on x86_64 Fedora 17.
2013-02-14 Pedro Alves <palves@redhat.com>
* tracepoint.c (cmd_qtdpsrc): Use savestring.
This makes gdbserver share gdb's savestring, instead of baking its own.
Tested on x86_64 Fedora 17.
gdb/
2013-02-14 Pedro Alves <palves@redhat.com>
* utils.c (savestring): Don't #undef it. Move function to
common/common-utils.c.
* common/common-utils.c: Include gdb_string.h.
(savestring): Move here from utils.c.
* common/common-utils.h (savestring): Declare.
gdb/gdbserver/
2013-02-14 Pedro Alves <palves@redhat.com>
* tracepoint.c (save_string): Delete.
(add_tracepoint_action): Use savestring instead of save_string.
null ptr check to prevent gdbserver from crashing
Evaluating a thread local storage variable in a remote scenario crashes
gdbserver if libthread-db could not be loaded.
2013-02-12 Sanimir Agovic <sanimir.agovic@intel.com>
gdbserver/
* thread-db.c (thread_db_get_tls_address):
NULL pointer check thread_db.
testsuite/
* gdb.server/no-thread-db.exp: New file.
* gdb.server/no-thread-db.c: New file.
* gdb.server/Makefile.in (EXECUTABLES): Add no-thread-db.
* linux-aarch64-low.c (aarch64_arch_setup): Clamp
aarch64_num_wp_regs and aarch64_num_bp_regs to
AARCH64_HWP_MAX_NUM and AARCH64_HBP_MAX_NUM respectively.
... following Pedro's advice of using a temporary macro.
gdb/gdbserver/ChangeLog:
* lynx-low.c (ptrace_request_to_str): Define a temporary
macro and use it to simplify this function's implementation.
This is not strictly needed, since both GDB and GDBserver seem
to agree on the register numbering without this. But this allows
us to make sure that this is always going to be the case.
gdb/gdbserver/ChangeLog:
* configure.srv (i[34567]86-*-lynxos*): Set srv_xmlfiles.
... back to GDB. The transfer occurs when GDB sends the
'qXfer:features:read:target.xml' packet. This allows us to make
sure that GDB and GDBserver use the same register numbering.
This is important on Lynx 178, where GDB selects the rs6000:6000
architecture by default instead of the powerpc:common architecture.
gdb/gdbserver/ChangeLog:
* configure.srv (powerpc-*-lynxos*): Set srv_xmlfiles.
Before this patch, the ptid passed to lynx_resume was completely
ignored, and we used the current_inferior. This resulted in trying
to resume the inferior execution using the wrong ptid after having
received a thread create/exit event, because the inferior_ptid
was still set to the ptid prior to receiving the signal.
gdb/gdbserver/ChangeLog:
* lynx-low.c (lynx_resume): Use the resume_info parameter
to determine the ptid for the lynx_ptrace call, unless
it is equal to minus_one_ptid, in which case we use the
ptid of the current_inferior.
(lynx_wait_1): After having received a thread create/exit
event, resume the inferior's execution using the signaling
thread's ptid, rather than the old ptid.
We use this ptrace request when handling SIGTRAP signals,
and without this change, the debug trances show:
PTRACE (<unknown-request>, ...
This patch fixes this.
gdb/gdbserver/ChangeLog:
* lynx-low.c (ptrace_request_to_str): Add handling for
PTRACE_GETTRACESIG.
LynxOS 178 does not define this macro.
gdb/gdbserver/ChangeLog:
* lynx-low.c (ptrace_request_to_str): Do not handle
PTRACE_GETTHREADLIST if this macro does not exist.
2012-11-26 Maxime Villard <rustyBSD@gmx.fr>
Pedro Alves <palves@redhat.com>
* common/linux-osdata.c (linux_xfer_osdata_fds): Decrease buffer
size parameter passed to readlink by one byte.
* fbsd-nat.c (fbsd_pid_to_exec_file): Ditto.
* linux-nat.c (linux_child_pid_to_exec_file): Ditto.
* nbsd-nat.c (nbsd_pid_to_exec_file): Ditto.
* inf-child.c (inf_child_fileio_readlink): Decrease local buffer's
size by one byte.
gdb/gdbserver/
2012-11-26 Maxime Villard <rustyBSD@gmx.fr>
* hostio.c (handle_readlink): Decrease buffer size
parameter passed to readlink by one byte.
ARI fixes: move gdb_wait and gdb_stat headers to common subdirectory.
* gdb_stat.h: Delete. Moved to common directory.
* common/gdb_stat.h: New file.
* gdb_wait.h: Delete. Moved to common directory.
* common/gdb_wait.h: New file.
* Makefile.in (H_FILES_NO_SRC): Adapt to new header
location.
* contrib/ari/gdb_ari.sh (wait.h rule): Adapt to new gdb_wait.h
location.
(stat.h rule): Adapt to new gdb_stat.h location.
* common/linux-osdata.c: Include "gdb_stat.h" header instead of
<sys/stat.h> header.
* common/linux-ptrace.c: Include "gdb_wait.h" header instead of
<sys/wait.h> header.
gdbserver ChangeLog entry:
2012-11-15 Pierre Muller <muller@sourceware.org>
* configure.ac (AC_CHECK_HEADERS): Add wait.h header.
* config.in: Regenerate.
* configure: Regenerate.
* linux-low.c: Use "gdb_stat.h" header instead of <sys/stat.h> header.
Use "gdb_wait.h" header instead of <sys/wait.h> header.
* lynx-low.c: Use "gdb_wait.h" header instead of <sys/wait.h> header.
* remote-utils.c: Use "gdb_stat.h" header instead of <sys/stat.h>
header.
* server.c: Remove HAVE_WAIT_H conditional. Use "gdb_wait.h" header
instead of <sys/wait.h> header.
* spu-low.c: Use "gdb_wait.h" header instead of <sys/wait.h> header.
gdb/ChangeLog
* target.c (simple_search_memory): Include access length in
warning message.
gdb/gdbserver/ChangeLog
* server.c (handle_search_memory_1): Include access length in
warning message.
gdb/testsuite/ChangeLog
Test find command on unmapped memory.
* gdb.base/find-unmapped.c: New file.
* gdb.base/find-unmapped.exp: New file.
* common/gdb_string.h: ... here.
* common/vec.h: Remove #ifndef GDBSERVER conditional inclusion of
gdb_string.h and gdb_assert.h.
gdbserver/
* configure.ac: Add check for strstr.
* config.in: Regenerate.
* configure: Regenerate.
* linux-thread-db.c: #include "gdb_vecs.h".
(try_thread_db_load_from_pdir_1): New arg "subdir". All callers
updated.
(try_thread_db_load_from_pdir): New arg "subdir". All callers updated.
(thread_db_load_search): Use a vector to iterate over path elements.
Handle text appearing after "$pdir".
gdbserver/
* Makefile.in (SFILES): Add gdb_vecs.c.
(OBS): Add gdb_vecs.o.
(gdb_vecs_h, host_defs_h): New variables.
(thread-db.o): Add $(gdb_vecs_h) dependency.
(gdb_vecs.o): New rule.
* thread-db.c: #include "gdb_vecs.h".
(thread_db_load_search): Use a vector to iterate over path elements.
Handle text appearing after "$pdir".
* inf-child.c (inf_child_fileio_pwrite): If pwrite fails, fall back
to attempting lseek/write.
(inf_child_fileio_pread): Likewise for pread.
gdbserver/ChangeLog:
* hostio.c (handle_pread): If pread fails, fall back to attempting
lseek/read.
(handle_pwrite): Likewise for pwrite.
* linux-arm-low.c (arm_linux_hw_point_initialize): Distinguish
between unsupported TYPE and unimplementable ADDR/LEN combination.
(arm_insert_point): Act on new return value.
testsuite/ChangeLog:
* gdb.base/watchpoint.exp (test_wide_location_1): Expect software
watchpoints on ARM. When expecting software watchpoints, tolerate
(remote) targets that report unsupported hardware watchpoint only
at continue time.
(test_wide_location_2): Likewise.
* server.c (process_point_options): Only skip tokens if we find
one that is unrecognized. Don't treat 'X' specially while
skipping unrecognized tokens.
* arm-linux-nat.c (arm_linux_hw_breakpoint_initialize): Do not
attempt to 4-byte-align HW breakpoint addresses for Thumb.
gdbserver/ChangeLog:
* linux-arm-low.c (arm_linux_hw_point_initialize): Do not attempt
to 4-byte-align HW breakpoint addresses for Thumb.
* solib-svr4.c (svr4_current_sos): New comment on
svr4_current_sos_via_xfer_libraries fall back.
gdb/gdbserver/
* linux-low.c (linux_qxfer_libraries_svr4): Return -1 if R_DEBUG is -1.
gdb/testsuite/
* gdb.server/solib-list-lib.c: New file.
* gdb.server/solib-list-main.c: New file.
* gdb.server/solib-list.exp: New file.
* linux-low (__UCLIBC__ && !(__UCLIBC_HAS_MMU__ || __ARCH_HAS_MMU__)):
Include asm/ptrace.h.
(PT_TEXT_ADDR, PT_DATA_ADDR, PT_TEXT_END_ADDR): Define only if not
already defined.
Pedro Alves <palves@redhat.com>
* linux-low.c (enum stopping_threads_kind): New.
(stopping_threads): Change type to `enum stopping_threads_kind'.
(handle_extended_wait): If stopping and suspending threads, leave
the new_lwp suspended too.
(linux_wait_for_event): Adjust.
(stop_all_lwps): Set `stopping_threads' to
STOPPING_AND_SUSPENDING_THREADS or STOPPING_THREADS depending on
whether we're suspending threads or just stopping them. Assert no
recursion happens.
(PTRACE_ARG4_TYPE): Likewise.
(PTRACE_XFER_TYPE): Likewise.
* linux-arm-low.c (arm_prepare_to_resume): Cast third argument of
ptrace to PTRACE_ARG3_TYPE.
* linux-low.c (PTRACE_ARG3_TYPE): Move macro to linux-low.h.
(PTRACE_ARG4_TYPE): Likewise.
(PTRACE_XFER_TYPE): Likewise.
(linux_detach_one_lwp): Cast fourth argument of
ptrace to long then PTRACE_ARG4_TYPE.
(regsets_fetch_inferior_registers): Cast third argument of
ptrace to long then PTRACE_ARG3_TYPE.
(regsets_store_inferior_registers): Likewise.
PR gdb/13969
* linux-low.c (linux_pid_exe_is_elf_64_file): Also return the
e_machine field.
(linux_qxfer_libraries_svr4): Update call to elf_64_file_p.
* linux-low.h (linux_pid_exe_is_elf_64_file): Updated.
* linux-x86-low.c (x86_arch_setup): Check if GDBserver is
compatible with process.
Jan Kratochvil <jan.kratochvil@redhat.com>
* server.c (cont_thread, general_thread): Add describing comments.
(start_inferior): Clear `cont_thread'.
(handle_v_cont): Don't set `cont_thread' if resuming all threads
of a process.
* common/linux-procfs.c (linux_proc_get_int): New, from
linux_proc_get_tgid, change its LWPID type to pid_t, add parameter
field.
(linux_proc_get_tgid): Only call linux_proc_get_int.
(linux_proc_get_tracerpid): New.
(linux_proc_pid_has_state): New, from linux_proc_pid_is_zombie.
(linux_proc_pid_is_stopped, linux_proc_pid_is_zombie): Only call
linux_proc_pid_has_state.
* common/linux-procfs.h (linux_proc_get_tracerpid): New declaration.
* common/linux-ptrace.c: Include linux-procfs.h and buffer.h.
(linux_ptrace_attach_warnings): New.
* common/linux-ptrace.h (struct buffer, linux_ptrace_attach_warnings):
New declaration.
* linux-nat.c: Include exceptions.h, linux-ptrace.h and buffer.h.
(linux_nat_attach): New variables ex, buffer, message and message_s.
Wrap to_attach by TRY_CATCH and call linux_ptrace_attach_warnings.
gdb/gdbserver/
* linux-low.c (linux_attach_lwp_1): New variable buffer. Call
linux_ptrace_attach_warnings.
gdb/testsuite/
* gdb.base/attach-twice.c: New files.
* gdb.base/attach-twice.exp: New files.