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.
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.
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.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
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.
* 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.
* 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.
* inferiors.c (add_pid_to_list, pull_pid_from_list): Delete.
* linux-low.c (struct simple_pid_list): New.
(stopped_pids): New a struct simple_pid_list pointer.
(add_to_pid_list, pull_pid_from_list): New.
(handle_extended_wait): Don't assume the first signal new children
report is SIGSTOP. Adjust call to pull_pid_from_list.
(linux_wait_for_lwp): Adjust.
2012-02-29 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* linux-low.c (linux_wait_1): Call unsuspend_all_lwps when
`step_over_finished' is true.
gdb/testsuite:
2012-02-29 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* gdb.trace/trace-mt.c: New
* gdb.trace/trace-mt.exp: New.
gdb/gdbserver/
* linux-low.c (pid_is_stopped): Delete, moved to common/.
(linux_attach_lwp_1): Adjust to use linux_proc_pid_is_stopped.
gdb/
* linux-nat.c (pid_is_stopped): Delete, moved to common/.
(linux_nat_post_attach_wait): Adjust to use
linux_proc_pid_is_stopped.
* common/linux-procfs.h (linux_proc_pid_is_stopped): Declare.
* common/linux-procfs.c (linux_proc_pid_is_stopped): New function,
based on pid_is_stopped from both linux-nat.c and
gdbserver/linux-low.c, and renamed.
* server.c (handle_query): Advertise support for target-side
breakpoint condition evaluation.
(process_point_options): New function.
(process_serial_event): When inserting a breakpoint, check for
a target-side condition that should be evaluated.
* mem-break.c: Include regcache.h and ax.h.
(point_cond_list_t): New data structure.
(breakpoint) <cond_list>: New field.
(find_gdb_breakpoint_at): Make non-static.
(delete_gdb_breakpoint_at): Clear any target-side
conditions.
(clear_gdb_breakpoint_conditions): New function.
(add_condition_to_breakpoint): Likewise.
(add_breakpoint_condition): Likewise.
(gdb_condition_true_at_breakpoint): Likewise.
(gdb_breakpoint_here): Return result directly instead
of going through a local variable.
* mem-break.h (find_gdb_breakpoint_at): New prototype.
(clear_gdb_breakpoint_conditions): Likewise.
(add_breakpoint_condition): Likewise.
(gdb_condition_true_at_breakpoint): Likewise.
* linux-low.c (linux_wait_1): Evaluate target-side breakpoint condition.
(need_step_over_p): Take target-side breakpoint condition into
consideration.
Try SIGKILL first, then PTRACE_KILL.
* linux-low.c (linux_kill_one_lwp): New.
(linux_kill_one_lwp): Rename to ...
(kill_one_lwp_callback): ... this. Use the new
linux_kill_one_lwp.
* linux-low.c (linux_wait_for_event_1): Rename to ...
(linux_wait_for_event): ... here and merge it with former
linux_wait_for_event - new variable wait_ptid, use it.
(linux_wait_for_event): Remove - merge it to linux_wait_for_event_1.
* linux-low.c (linux_create_inferior): Put empty if clause for write.
Revert:
2011-12-18 Hui Zhu <teawater@gmail.com>
* linux-low.c (linux_create_inferior): Save return value to ret.