I adjusted a test to do 'expect -i $server_spawn_id -re ...', and saw
really strange behavior. Whether that expect would work, depended on
whether GDB would also send output and the same expect matched it too
(on $gdb_spawn_id). I was perplexed until I noticed that
gdbserver_spawn spawns gdbserver and then uses expect_background to
reap gdbserver. That expect_background conflicts/races with any
"expect -i $server_spawn_id" done anywhere else in parallel...
In order to make it possible for tests to read inferior I/O out of
$server_spawn_id, we to get rid of that expect_background. This patch
makes us instead reap gdbserver's spawn id when GDB exits. If GDB is
still around, this gives a chance for gdbserver to exit cleanly. The
current code in gdb_finish uses "kill", but that doesn't work with
extended-remote (gdbserver doesn't exit). We now use "monitor exit"
instead which works in both remote and extended-remote modes.
gdb/testsuite/ChangeLog:
2015-04-07 Pedro Alves <palves@redhat.com>
* lib/gdb.exp (gdb_finish): Delete persistent gdbserver handling.
* lib/gdbserver-support.exp (gdbserver_start): Make
$server_spawn_id global.
(gdbserver_start): Don't wait for gdbserver's spawn id with
expect_background.
(close_gdbserver): New procedure.
(gdb_exit): Rename the default version and reimplement.
While teaching gdb_test_multiple to forward "-i" to gdb_expect, I
found that with:
gdb_test_multiple (...) {
-i $some_variable -re "..." {}
}
$some_variable was not getting expanded in the gdb_test_multiple
caller's scope. This is a bug inside gdb_test_multiple. When
processing an argument in passed in user code, it was appending the
original argument literally, instead of appending the uplist'ed
argument.
gdb/testsuite/ChangeLog:
2015-04-07 Pedro Alves <palves@redhat.com>
* lib/gdb.exp (gdb_test_multiple): When processing an argument,
append the substituted item, not the original item.
Working on splitting gdb and inferior output handling in this test, I
noticed a race that happens to be masked out today.
The test sends "a\n" to the inferior, and then inferior echoes back
"a\n".
If expect manages to read only the first "a\r\n" into its buffer, then
this matches:
-re "^a\r\n(|a\r\n)$" {
and leaves the second "a\r\n" in output.
Then the next test that processes inferior I/O sends "data\n", and expects:
-re "^(\r\n|)data\r\n(|data\r\n)$"
which fails given the anchor and given "a\r\n" is still in the buffer.
This is masked today because the test relies on inferior I/O being
done on GDB's terminal, and there are tested GDB commands in between,
which consume the "a\r\n" that was left in the output.
We don't support SunOS4 anymore, so just remove the workaround.
gdb/testsuite/ChangeLog
2015-04-07 Pedro Alves <palves@redhat.com>
* gdb.base/interrupt.exp: Don't handle the case of the inferior
output appearing once only.
I saw this on PPC64 once:
not installed on target
(gdb) PASS: gdb.trace/actions.exp: 5.10a: verify teval actions set for two tracepoints
break main
Breakpoint 4 at 0x10000c6c: file ../../../src/gdb/testsuite/gdb.trace/actions.c, line 139.
(gdb) PASS: gdb.trace/actions.exp: break main
run
Starting program: /home/palves/gdb/build/gdb/testsuite/outputs/gdb.trace/actions/actions
tstatus
Breakpoint 4, main (argc=1, argv=0x3fffffffebb8, envp=0x3fffffffebc8) at ../../../src/gdb/testsuite/gdb.trace/actions.c:139
139 begin ();
(gdb) tstatus
Trace can not be run on this target.
(gdb) actions 1
Enter actions for tracepoint 1, one per line.
End with a line saying just "end".
>collect $regs
>end
(gdb) PASS: gdb.trace/actions.exp: set actions for first tracepoint
tstart
You can't do that when your target is `native'
(gdb) FAIL: gdb.trace/actions.exp: tstart
info tracepoints 1
Num Type Disp Enb Address What
1 tracepoint keep y 0x00000000100007c8 in gdb_c_test at ../../../src/gdb/testsuite/gdb.trace/actions.c:74
collect $regs
not installed on target
...
followed by a cascade of FAILs. The "tstatus" was supposed to detect
that this target (native) can't do tracepoints, but, alas, it didn't.
That detection failed because 'gdb_test "break main"' doesn't expect
anything, and then the output was slow enough that 'gdb_test ""
"Breakpoint .*"' matched the output of "break main"...
The fix is to use gdb_breakpoint instead. Also check the result of
gdb_test while at it.
Tested on x86-64 Fedora 20, native and gdbserver.
gdb/testsuite/ChangeLog:
2015-04-07 Pedro Alves <palves@redhat.com>
* gdb.trace/actions.exp: Use gdb_breakpoint instead of gdb_test
that doesn't expect anything. Return early if running to main
fails.
On GNU/Linux, if the running kernel supports clone events, then
linux-thread-db.c defers thread listing to the target beneath:
static void
thread_db_update_thread_list (struct target_ops *ops)
{
...
if (target_has_execution && !thread_db_use_events ())
ops->beneath->to_update_thread_list (ops->beneath);
else
thread_db_update_thread_list_td_ta_thr_iter (ops);
...
}
However, when live debugging, the target beneath, linux-nat.c, does
not implement the to_update_thread_list method. The result is that if
a thread is marked exited (because it can't be deleted right now,
e.g., it was the selected thread), then it won't ever be deleted,
until the process exits or is killed/detached.
A similar thing happens with the remote.c target. Because its
target_update_thread_list implementation skips exited threads when it
walks the current thread list looking for threads that no longer exits
on the target side, using ALL_NON_EXITED_THREADS_SAFE, stale exited
threads are never deleted.
This is not a big deal -- I can't think of any way this might be user
visible, other than gdb's memory growing a tiny bit whenever a thread
gets stuck in exited state. Still, might as well clean things up
properly.
All other targets use prune_threads, so are unaffected.
The fix adds a ALL_THREADS_SAFE macro, that like
ALL_NON_EXITED_THREADS_SAFE, walks the thread list and allows deleting
the iterated thread, and uses that in places that are walking the
thread list in order to delete threads. Actually, after converting
linux-nat.c and remote.c to use this, we find the only other user of
ALL_NON_EXITED_THREADS_SAFE is also walking the list to delete
threads. So we convert that too, and end up deleting
ALL_NON_EXITED_THREADS_SAFE.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/ChangeLog
2015-04-07 Pedro Alves <palves@redhat.com>
* gdbthread.h (ALL_NON_EXITED_THREADS_SAFE): Rename to ...
(ALL_THREADS_SAFE): ... this, and don't skip exited threads.
(delete_exited_threads): New declaration.
* infrun.c (follow_exec): Use ALL_THREADS_SAFE.
* linux-nat.c (linux_nat_update_thread_list): New function.
(linux_nat_add_target): Install it.
* remote.c (remote_update_thread_list): Use ALL_THREADS_SAFE.
* thread.c (prune_threads): Use ALL_THREADS_SAFE.
(delete_exited_threads): New function.
Although not currently possible in practice when we get here,
'resume_ptid' can also be a wildcard throughout this function. It's
clearer to fetch the regcache using the thread's ptid.
gdb/ChangeLog:
2015-04-07 Pedro Alves <pedro@codesourcery.com>
* infrun.c (resume) <displaced stepping debug output>: Get the
leader thread's regcache, not resume_ptid's.
Nowadays, the alarm value is 60, and alarm is generated on some slow
boards. This patch is to pass DejaGNU timeout value to the program,
and move the alarm call before going to infinite loop. If any thread
has activities, the alarm is reset.
gdb/testsuite:
2015-04-07 Yao Qi <yao.qi@linaro.org>
* gdb.threads/non-stop-fair-events.c (SECONDS): New macro.
(child_function): Call alarm.
(main): Move call to alarm into the loop.
* gdb.threads/non-stop-fair-events.exp: Build program with
-DTIMEOUT=$timeout.
The "dest" parameter to fpc_compile/gpc_compile is the name of
compilation destination file, not a board name.
This patch fixes this by using names consistent with
lib/future.exp:gdb_default_target_compile.
gdb/testsuite/ChangeLog:
* lib/pascal.exp (gpc_compile): Rename dest arg to destfile.
Fix dest parameter to board_info.
(fpc_compile): Ditto.
(gdb_compile_pascal): Rename dest arg to destfile.
gdb/ChangeLog:
* symtab.c (hash_symbol_entry): Hash STRUCT_DOMAIN symbols as
VAR_DOMAIN.
(symbol_cache_lookup): Clarify use of bsc_ptr, slot_ptr parameters.
Include symbol domain in debugging output.
Currently building gdb is impossible without an installed termcap or
curses library. But, GDB already has a very minimal termcap in the
tree to handle this situation for Windows -- gdb/stub-termcap.c. This
patch makes that the fallback for all hosts.
Testing this on GNU/Linux (by simply hacking away the termcap/curses
detection in gdb/configure.ac), we trip on:
../readline/libreadline.a(terminal.o): In function `_rl_init_terminal_io':
/home/pedro/gdb/mygit/src/readline/terminal.c:527: undefined reference to `PC'
/home/pedro/gdb/mygit/src/readline/terminal.c:528: undefined reference to `BC'
/home/pedro/gdb/mygit/src/readline/terminal.c:529: undefined reference to `UP'
/home/pedro/gdb/mygit/src/readline/terminal.c:538: undefined reference to `PC'
/home/pedro/gdb/mygit/src/readline/terminal.c:539: undefined reference to `BC'
/home/pedro/gdb/mygit/src/readline/terminal.c:540: undefined reference to `UP'
These are globals that are normally defined by termcap (or ncurses'
termcap emulation).
Now, we could just define replacements in stub-termcap.c, but
readline/terminal.c (at least the copy in our tree) has this:
#if !defined (__linux__) && !defined (NCURSES_VERSION)
# if defined (__EMX__) || defined (NEED_EXTERN_PC)
extern
# endif /* __EMX__ || NEED_EXTERN_PC */
char PC, *BC, *UP;
#endif /* !__linux__ && !NCURSES_VERSION */
which can result in readline defining the globals too. That will
usually work out in C, given that "-fcommon" is usually the default
for C compilers, but that won't work for C++, or C with -fno-common
(link fails with "multiple definition" errors)...
Mirroring those #ifdef conditions in the stub termcap screams
"brittle" to me -- I can see them changing in latter readline
versions.
Work around that by simply using __attribute__((weak)).
Windows/PE/COFF's do support weak, but not on gcc 3.4 based toolchains
(4.8.x does work). Given the file never needed the variables while it
was Windows-only, just continue not defining them there. All other
supported hosts should support this.
gdb/ChangeLog:
2015-04-06 Pedro Alves <palves@redhat.com>
Bernd Edlinger <bernd.edlinger@hotmail.de>
* configure.ac: Remove the mingw32-specific stub-termcap.o
fallback, and instead fallback to the stub termcap on all hosts.
* configure: Regenerate.
* stub-termcap.c [!__MINGW32__] (PC, BC, UP): Define as weak
symbols.
This paramater is no longer useful after the previous commit, so remove
it as a cleanup.
gdb/ChangeLog:
* gdbtypes.c (is_dynamic_type_internal): Remove the unused
"top_level" parameter.
(resolve_dynamic_type_internal): Remove the unused "top_level"
parameter. Update call to is_dynamic_type_internal.
(is_dynamic_type): Update call to is_dynamic_type_internal.
(resolve_dynamic_range): Update call to
resolve_dynamic_type_internal.
(resolve_dynamic_union): Likewise.
(resolve_dynamic_struct): Likewise.
(resolve_dynamic_type): Likewise.
Even when referenced types are dynamic, the corresponding referencing
type should not be considered as dynamic: it's only a pointer. This
prevents reference type for values not in memory to be resolved.
gdb/ChangeLog:
* gdbtypes.c (is_dynamic_type_internal): Remove special handling
of TYPE_CODE_REF types so that they are not considered as
dynamic depending on the referenced type.
(resolve_dynamic_type_internal): Likewise.
gdb/testsuite/ChangeLog:
* gdb.ada/funcall_ref.exp: New file.
* gdb.ada/funcall_ref/foo.adb: New file.
I see these two fails in no-unwaited-for-left.exp in remote testing
for aarch64-linux target.
...
continue
Continuing.
warning: Remote failure reply: E.No unwaited-for children left.
[Thread 1084] #2 stopped.
(gdb) FAIL: gdb.threads/no-unwaited-for-left.exp: continue stops when thread 2 exits
....
continue
Continuing.
warning: Remote failure reply: E.No unwaited-for children left.
[Thread 1081] #1 stopped.
(gdb) FAIL: gdb.threads/no-unwaited-for-left.exp: continue stops when the main thread exits
I checked the gdb.log on buildbot, and find that these two fails also
appear on Debian-i686-native-extended-gdbserver and Fedora-ppc64be-native-gdbserver-m64.
I recall that they are about local/remote parity, and related RSP is missing.
There has been already a PR 14618 about it. This patch is to kfail them
on remote target.
gdb/testsuite:
2015-04-02 Yao Qi <yao.qi@linaro.org>
* gdb.threads/no-unwaited-for-left.exp: Set up kfail if target
is remote.
This commit makes GDB default to a sysroot of "target:".
One testcase needed updating as a result of this change.
gdb/ChangeLog:
* main.c (captured_main): Set gdb_sysroot to "target:"
if not otherwise set.
gdb/testsuite/ChangeLog:
* gdb.base/break-probes.exp: Cope with "target:" sysroot.
This commit adds support for filenames prefixed with "target:" to
exec_file_attach. This is required to correctly follow inferior
exec* calls when a gdb_sysroot prefixed with "target:" is set.
gdb/ChangeLog:
* exec.c (exec_file_attach): Support "target:" filenames.
This commit updates solib_find to strip the "target:" prefix from
gdb_sysroot when accessing local files. This ensures that the same
search algorithm is used for local files regardless of whether a
"target:" prefix was used or not. It also avoids cluttering GDB's
output with unnecessary "target:" prefixes on paths.
gdb/ChangeLog:
* solib.c (solib_find): Strip "target:" prefix from sysroot
if accessing local files.
symfile_bfd_open handled what were remote files as a special case.
Converting from "remote:" files to "target:" made symfile_bfd_open
look like this:
if remote:
open bfd, check format, etc
return
local-specific stuff
open bfd, check format, etc
return
This commit rearranges symfile_bfd_open to remove the duplicated
code, like this:
if local:
local-specific stuff
open bfd, check format, etc
return
gdb/ChangeLog:
* symfile.c (symfile_bfd_open): Reorder to remove duplicated
checks and error messages.
The functionality of "target:" sysroots is a superset of the
functionality of "remote:" sysroots. This commit causes the
"set sysroot" command to rewrite "remote:" sysroots as "target:"
sysroots and replaces "remote:" specific code with "target:"
specific code where still necessary.
gdb/ChangeLog:
* remote.h (REMOTE_SYSROOT_PREFIX): Remove definition.
(remote_filename_p): Remove declaration.
(remote_bfd_open): Likewise.
* remote.c (remote_bfd_iovec_open): Remove function.
(remote_bfd_iovec_close): Likewise.
(remote_bfd_iovec_pread): Likewise.
(remote_bfd_iovec_stat): Likewise.
(remote_filename_p): Likewise.
(remote_bfd_open): Likewise.
* symfile.h (gdb_bfd_open_maybe_remote): Remove declaration.
* symfile.c (separate_debug_file_exists): Use gdb_bfd_open.
(gdb_bfd_open_maybe_remote): Remove function.
(symfile_bfd_open): Replace remote filename check with
target filename check.
(reread_symbols): Use gdb_bfd_open.
* build-id.c (gdbcore.h): New include.
(build_id_to_debug_bfd): Use gdb_bfd_open.
* infcmd.c (attach_command_post_wait): Remove remote filename
check.
* solib.c (solib_find): Replace remote-specific handling with
target-specific handling. Update comments where necessary.
(solib_bfd_open): Replace remote-specific handling with
target-specific handling.
(gdb_sysroot_changed): New function.
(_initialize_solib): Call the above when gdb_sysroot changes.
* windows-tdep.c (gdbcore.h): New include.
(windows_xfer_shared_library): Use gdb_bfd_open.
This commit updates gdb_bfd_open to access files using target
fileio functions if the supplied path starts with "target:"
and if the local and target filesystems are not the same.
This allows users to specify "set sysroot target:" and have
GDB access files locally or from the remote as appropriate.
The new functions in gdb_bfd.c are copies of functions from
remote.c. This duplication is intentional and will be removed
by the next commit in this series.
gdb/ChangeLog:
* gdb/gdb_bfd.h (TARGET_SYSROOT_PREFIX): New definition.
(is_target_filename): New declaration.
(gdb_bfd_has_target_filename): Likewise.
(gdb_bfd_open): Update documentation comment.
* gdb_bfd.c (target.h): New include.
(gdb/fileio.h): Likewise.
(is_target_filename): New function.
(gdb_bfd_has_target_filename): Likewise.
(fileio_errno_to_host): Likewise.
(gdb_bfd_iovec_fileio_open): Likewise.
(gdb_bfd_iovec_fileio_pread): Likewise.
(gdb_bfd_iovec_fileio_close): Likewise.
(gdb_bfd_iovec_fileio_fstat): Likewise.
(gdb_bfd_open): Use target fileio to access paths prefixed
with "target:" where necessary.
This commit introduces a new target method target_filesystem_is_local
which can be used to determine whether or not the filesystem accessed
by the target_fileio_* methods is the local filesystem.
gdb/ChangeLog:
* target.h (struct target_ops) <to_filesystem_is_local>:
New field.
(target_filesystem_is_local): New macro.
* target-delegates.c: Regenerate.
* remote.c (remote_filesystem_is_local): New function.
(init_remote_ops): Initialize to_filesystem_is_local.
This commit introduces a new target method target_fileio_fstat
which can be used to retrieve information about files opened with
target_fileio_open.
gdb/ChangeLog:
* target.h (struct target_ops) <to_fileio_fstat>: New field.
(target_fileio_fstat): New declaration.
* target.c (target_fileio_fstat): New function.
* inf-child.c (inf_child_fileio_fstat): Likewise.
(inf_child_target): Initialize to_fileio_fstat.
* remote.c (init_remote_ops): Likewise.
My all-stop-on-top-of-non-stop series manages to shows regressions due
to this latent bug. currently_stepping returns true if
stepped_breakpoint is set. Obviously we should clear
it before checking currently_stepping, not after.
Tested on x86_64 Fedora 20.
gdb/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* infrun.c (resume): Check currently_stepping after clearing
stepped_breakpoint, not before.
If interrupt_and_wait manages to trigger the FAIL path, we get:
ERROR OCCURED: can't read "test": no such variable
gdb/testsuite/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* gdb.threads/manythreads.exp (interrupt_and_wait): Pass $message
to fail instead of non-existent $test.
By inspection, I noticed a path where we return without discarding the
cleanups.
gdb/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* infrun.c (keep_going): Also discard cleanups if inserting
breakpoints fails.
Noticed that if an error is thrown out of target_wait, we miss running
finish_thread_state_cleanup.
Tested on x86_64 Fedora 20, with "maint set target-async off".
gdb/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* infrun.c (wait_for_inferior): Install the
finish_thread_state_cleanup cleanup across the whole function, not
just around handle_inferior_event.
We can use the recently added do_target_resume do simplify the code a
bit here.
Tested on x86_64 Fedora 20.
gdb/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* infrun.c (resume) <step past permanent breakpoint>: Use
do_target_resume.
My all-stop-on-top-of-non-stop series manages to trip on a bug in the
linux-nat.c backend while running the testsuite. If a thread is
discovered while threads are being momentarily paused (without the
core's intervention), the thread ends up stuck in THREAD_STOPPED
state, even though from the user's perspective, the thread is running
even while it is paused.
From inspection, in the current sources, this can happen if we call
stop_and_resume_callback, though there's no way to test that with
current Linux kernels.
(While trying to come up with test to exercise this, I stumbled on:
https://sourceware.org/ml/gdb-patches/2015-03/msg00850.html
... which does include a non-trivial test, so I think I can still
claim I come out net positive. :-) )
Tested on x86_64 Fedora 20.
gdb/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* linux-nat.c (linux_handle_extended_wait): Always call set_running.
On GNU/Linux, if the target reuses the TID of a thread that GDB still
has in its list marked as THREAD_EXITED, GDB crashes, like:
(gdb) continue
Continuing.
src/gdb/thread.c:789: internal-error: set_running: Assertion `tp->state != THREAD_EXITED' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) FAIL: gdb.threads/tid-reuse.exp: continue to breakpoint: after_reuse_time (GDB internal error)
Here:
(top-gdb) bt
#0 internal_error (file=0x953dd8 "src/gdb/thread.c", line=789, fmt=0x953da0 "%s: Assertion `%s' failed.")
at src/gdb/common/errors.c:54
#1 0x0000000000638514 in set_running (ptid=..., running=1) at src/gdb/thread.c:789
#2 0x00000000004bda42 in linux_handle_extended_wait (lp=0x16f5760, status=0, stopping=0) at src/gdb/linux-nat.c:2114
#3 0x00000000004bfa24 in linux_nat_filter_event (lwpid=20570, status=198015) at src/gdb/linux-nat.c:3127
#4 0x00000000004c070e in linux_nat_wait_1 (ops=0xe193d0, ptid=..., ourstatus=0x7fffffffd2c0, target_options=1) at src/gdb/linux-nat.c:3478
#5 0x00000000004c1015 in linux_nat_wait (ops=0xe193d0, ptid=..., ourstatus=0x7fffffffd2c0, target_options=1) at src/gdb/linux-nat.c:3722
#6 0x00000000004c92d2 in thread_db_wait (ops=0xd80b60 <thread_db_ops>, ptid=..., ourstatus=0x7fffffffd2c0, options=1)
at src/gdb/linux-thread-db.c:1525
#7 0x000000000066db43 in delegate_wait (self=0xd80b60 <thread_db_ops>, arg1=..., arg2=0x7fffffffd2c0, arg3=1) at src/gdb/target-delegates.c:116
#8 0x000000000067e54b in target_wait (ptid=..., status=0x7fffffffd2c0, options=1) at src/gdb/target.c:2206
#9 0x0000000000625111 in fetch_inferior_event (client_data=0x0) at src/gdb/infrun.c:3275
#10 0x0000000000648a3b in inferior_event_handler (event_type=INF_REG_EVENT, client_data=0x0) at src/gdb/inf-loop.c:56
#11 0x00000000004c2ecb in handle_target_event (error=0, client_data=0x0) at src/gdb/linux-nat.c:4655
I managed to come up with a test that reliably reproduces this. It
spawns enough threads for the pid number space to wrap around, so
could potentially take a while. On my box that's 4 seconds; on
gcc110, a PPC box which has max_pid set to 65536, it's over 10
seconds. So I made the test compute how long that would take, and cap
the time waited if it would be unreasonably long.
Tested on x86_64 Fedora 20.
gdb/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* linux-thread-db.c (record_thread): Readd the thread to gdb's
list if it was marked exited.
gdb/testsuite/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
* gdb.threads/tid-reuse.c: New file.
* gdb.threads/tid-reuse.exp: New file.
--attach/--multi are currently only mentioned on the usage info first
lines, the meaning of PROG is completely absent and the COMM text does
not mention '-/stdio'.
A few options are missing:
. --disable-randomization / --no-disable-randomization is not mentioned.
Although the manual has a comment saying these are superceded by
QDisableRandomization, that only makes sense for "run" in
extended-remote mode. When we start gdbserver passing it a PROG,
--disable-randomization / --no-disable-randomization do take effect.
So I think we should document these.
. We show --debug / --remote-debug, so might as well show --disable-packet too.
GDB's --help has this "For more information, consult the GDB manual"
blurb that is missing in GDBserver's --help.
Then shuffle things around a bit into "Operating modes", "Other
options" and "Debug options" sections, similarly to GDB's --help
structure.
Before:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$ ./gdbserver/gdbserver --help
Usage: gdbserver [OPTIONS] COMM PROG [ARGS ...]
gdbserver [OPTIONS] --attach COMM PID
gdbserver [OPTIONS] --multi COMM
COMM may either be a tty device (for serial debugging), or
HOST:PORT to listen for a TCP connection.
Options:
--debug Enable general debugging output.
--debug-format=opt1[,opt2,...]
Specify extra content in debugging output.
Options:
all
none
timestamp
--remote-debug Enable remote protocol debugging output.
--version Display version information and exit.
--wrapper WRAPPER -- Run WRAPPER to start new programs.
--once Exit after the first connection has closed.
Report bugs to "<http://www.gnu.org/software/gdb/bugs/>".
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
After:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
$ ./gdbserver/gdbserver --help
Usage: gdbserver [OPTIONS] COMM PROG [ARGS ...]
gdbserver [OPTIONS] --attach COMM PID
gdbserver [OPTIONS] --multi COMM
COMM may either be a tty device (for serial debugging),
HOST:PORT to listen for a TCP connection, or '-' or 'stdio' to use
stdin/stdout of gdbserver.
PROG is the executable program. ARGS are arguments passed to inferior.
PID is the process ID to attach to, when --attach is specified.
Operating modes:
--attach Attach to running process PID.
--multi Start server without a specific program, and
only quit when explicitly commanded.
--once Exit after the first connection has closed.
--help Print this message and then exit.
--version Display version information and exit.
Other options:
--wrapper WRAPPER -- Run WRAPPER to start new programs.
--disable-randomization
Run PROG with address space randomization disabled.
--no-disable-randomization
Don't disable address space randomization when
starting PROG.
Debug options:
--debug Enable general debugging output.
--debug-format=opt1[,opt2,...]
Specify extra content in debugging output.
Options:
all
none
timestamp
--remote-debug Enable remote protocol debugging output.
--disable-packet=opt1[,opt2,...]
Disable support for RSP packets or features.
Options:
vCont, Tthread, qC, qfThreadInfo and
threads (disable all threading packets).
For more information, consult the GDB manual (available as on-line
info or a printed manual).
Report bugs to "<http://www.gnu.org/software/gdb/bugs/>".
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
gdb/gdbserver/ChangeLog:
2015-04-01 Pedro Alves <palves@redhat.com>
Cleber Rosa <crosa@redhat.com>
* server.c (gdbserver_usage): Reorganize and extend the usage
message.
This patch, as the subject says, extends GDB so that it is able to use
the contents of the file /proc/PID/coredump_filter when generating a
corefile. This file contains a bit mask that is a representation of
the different types of memory mappings in the Linux kernel; the user
can choose to dump or not dump a certain type of memory mapping by
enabling/disabling the respective bit in the bit mask. Currently,
here is what is supported:
bit 0 Dump anonymous private mappings.
bit 1 Dump anonymous shared mappings.
bit 2 Dump file-backed private mappings.
bit 3 Dump file-backed shared mappings.
bit 4 (since Linux 2.6.24)
Dump ELF headers.
bit 5 (since Linux 2.6.28)
Dump private huge pages.
bit 6 (since Linux 2.6.28)
Dump shared huge pages.
(This table has been taken from core(5), but you can also read about it
on Documentation/filesystems/proc.txt inside the Linux kernel source
tree).
The default value for this file, used by the Linux kernel, is 0x33,
which means that bits 0, 1, 4 and 5 are enabled. This is also the
default for GDB implemented in this patch, FWIW.
Well, reading the file is obviously trivial. The hard part, mind you,
is how to determine the types of the memory mappings. For that, I
extended the code of gdb/linux-tdep.c:linux_find_memory_regions_full and
made it rely *much more* on the information gathered from
/proc/<PID>/smaps. This file contains a "verbose dump" of the
inferior's memory mappings, and we were not using as much information as
we could from it. If you want to read more about this file, take a look
at the proc(5) manpage (I will also write a blog post soon about
everything I had to learn to get this patch done, and when I it is ready
I will post it here).
With Oleg Nesterov's help, we could improve the current algorithm for
determining whether a memory mapping is anonymous/file-backed,
private/shared. GDB now also respects the MADV_DONTDUMP flag and does
not dump the memory mapping marked as so, and will always dump
"[vsyscall]" or "[vdso]" mappings (just like the Linux kernel).
In a nutshell, what the new code is doing is:
- If the mapping is associated to a file whose name ends with
" (deleted)", or if the file is "/dev/zero", or if it is "/SYSV%08x"
(shared memory), or if there is no file associated with it, or if
the AnonHugePages: or the Anonymous: fields in the /proc/PID/smaps
have contents, then GDB considers this mapping to be anonymous.
There is a special case in this, though: if the memory mapping is a
file-backed one, but *also* contains "Anonymous:" or
"AnonHugePages:" pages, then GDB considers this mapping to be *both*
anonymous and file-backed, just like the Linux kernel does. What
that means is simple: this mapping will be dumped if the user
requested anonymous mappings *or* if the user requested file-backed
mappings to be present in the corefile.
It is worth mentioning that, from all those checks described above,
the most fragile is the one to see if the file name ends with
" (deleted)". This does not necessarily mean that the mapping is
anonymous, because the deleted file associated with the mapping may
have been a hard link to another file, for example. The Linux
kernel checks to see if "i_nlink == 0", but GDB cannot easily do
this check (as it has been discussed, GDB would need to run as root,
and would need to check the contents of the /proc/PID/map_files/
directory in order to determine whether the deleted was a hardlink
or not). Therefore, we made a compromise here, and we assume that
if the file name ends with " (deleted)", then the mapping is indeed
anonymous. FWIW, this is something the Linux kernel could do
better: expose this information in a more direct way.
- If we see the flag "sh" in the VmFlags: field (in /proc/PID/smaps),
then certainly the memory mapping is shared (VM_SHARED). If we have
access to the VmFlags, and we don't see the "sh" there, then
certainly the mapping is private. However, older Linux kernels (see
the code for more details) do not have the VmFlags field; in that
case, we use another heuristic: if we see 'p' in the permission
flags, then we assume that the mapping is private, even though the
presence of the 's' flag there would mean VM_MAYSHARE, which means
the mapping could still be private. This should work OK enough,
however.
Finally, it is worth mentioning that I added a new command, 'set
use-coredump-filter on/off'. When it is 'on', it will read the
coredump_filter' file (if it exists) and use its value; otherwise, it
will use the default value mentioned above (0x33) to decide which memory
mappings to dump.
gdb/ChangeLog:
2015-03-31 Sergio Durigan Junior <sergiodj@redhat.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
Oleg Nesterov <oleg@redhat.com>
PR corefiles/16092
* linux-tdep.c: Include 'gdbcmd.h' and 'gdb_regex.h'.
New enum identifying the various options of the coredump_filter
file.
(struct smaps_vmflags): New struct.
(use_coredump_filter): New variable.
(decode_vmflags): New function.
(mapping_is_anonymous_p): Likewise.
(dump_mapping_p): Likewise.
(linux_find_memory_regions_full): New variables
'coredumpfilter_name', 'coredumpfilterdata', 'pid', 'filterflags'.
Removed variable 'modified'. Read /proc/<PID>/smaps file; improve
parsing of its information. Implement memory mapping filtering
based on its contents.
(show_use_coredump_filter): New function.
(_initialize_linux_tdep): New command 'set use-coredump-filter'.
* NEWS: Mention the possibility of using the
'/proc/PID/coredump_filter' file when generating a corefile.
Mention new command 'set use-coredump-filter'.
gdb/doc/ChangeLog:
2015-03-31 Sergio Durigan Junior <sergiodj@redhat.com>
PR corefiles/16092
* gdb.texinfo (gcore): Mention new command 'set
use-coredump-filter'.
(set use-coredump-filter): Document new command.
gdb/testsuite/ChangeLog:
2015-03-31 Sergio Durigan Junior <sergiodj@redhat.com>
PR corefiles/16092
* gdb.base/coredump-filter.c: New file.
* gdb.base/coredump-filter.exp: Likewise.
When loading a corefile that has some inaccessible memory region(s),
GDB complains about it:
(gdb) core /my/corefile
[New LWP 28468]
Cannot access memory at address 0x355fc21148
Cannot access memory at address 0x355fc21140
(gdb)
However, despite not seeing the message "Core was generated by...", it
is still possible to inspect the corefile using regular GDB commands.
The reason for that is because read_memory_unsigned_integer throws an
exception when it cannot read the memory region, but
solib_svr4_r_ldsomap was not catching it. The fix is to catch the
exception and act accordingly.
Tested on Fedora 20 x86_64, no regressions found.
gdb/ChangeLog:
2015-03-31 Sergio Durigan Junior <sergiodj@redhat.com>
* solib-svr4.c (solib_svr4_r_ldsomap): Catch possible exception by
read_memory_unsigned_integer.
This patch adds cpu information on linux based on /proc/cpuinfo as :
cpus Listing of all cpus/cores on the system
This patch also reorders the info os commands so that they are listed
in alphabetical order.
gdb/ChangeLog:
* NEWS: Mention info os cpus support.
* gdb/nat/linux-osdata.c (linux_xfer_osdata_cpus): New function.
(struct osdata_type): Add cpus entry, reorder the entries in
alphabetical order.
gdb/doc/ChangeLog:
* gdb.texinfo (Operating System Auxiliary Information): Add info os cpus
documentation, reorder the info os entries in alphabetical order.
This allows triplets where the vendor is not set.
gdb/ChangeLog:
2015-03-31 Matthias Klose <doko@ubuntu.com>
* compile/compile.c (compile_to_object): Allow triplets with or
without vendor set.
gdb/ChangeLog:
* remote.c (remote_mourn_1): Remove function. Update all callers
to use remote_mourn.
(extended_remote_mourn_1): Remove function. Update all callers
to use extended_remote_mourn.
(extended_remote_attach_1): Remove function. Update all callers
to use extended_remote_attach.
Simon Marchi:
I think this patch is wrong. Starting with that commit (f30d5c7),
some tests (e.g. mi-break.exp) started to fail for me, because
of gdb segfaulting.
The address of expr is passed to the cleanup. When the cleanup is ran,
expr is no longer in scope, so what is at that address is probably not
safe to use anymore. That's my guess.
gdb/ChangeLog
2015-03-27 Jan Kratochvil <jan.kratochvil@redhat.com>
Revert:
2015-03-26 Jan Kratochvil <jan.kratochvil@redhat.com>
Code cleanup.
* printcmd.c (print_command_1): Move expr variable scope.
GCC 4.4.7 generates the following warning:
| cc1: warnings being treated as errors
| dtrace-probe.c: In function ‘dtrace_process_dof_probe’:
| dtrace-probe.c:416: error: ‘expr’ may be used uninitialized in this function
| make[2]: *** [dtrace-probe.o] Error 1
Later versions (GCC 5) do a better job and don't generate the warning,
but it does not hurt to pre-initialize "expr" to NULL.
gdb/ChangeLog:
* dtrace-probe.c (dtrace_process_dof_probe): Initialize expr to NULL.
