This updates the copyright headers to include 2025. I did this by
running gdb/copyright.py and then manually modifying a few files as
noted by the script.
Approved-By: Eli Zaretskii <eliz@gnu.org>
This commit changes how gdbserver stores the inferior arguments from
being a vector of separate arguments into a single string with all of
the arguments combined together.
Making this change might feel a little strange; intuitively it feels
like we would be better off storing the arguments as a vector, but
this change is part of a larger series of work that aims to improve
GDB's inferior argument handling. The full series was posted here:
https://inbox.sourceware.org/gdb-patches/cover.1730731085.git.aburgess@redhat.com
But asking people to review a 14 patch series in unreasonable, so I'm
instead posting the patches in smaller batches. This patch can stand
alone, and I do think this change makes sense on its own:
First, GDB already stores the inferior arguments as a single string,
so doing this moves gdbserver into line with GDB. The common code
into which gdbserver calls requires the arguments to be a single
string, so currently each target's create_inferior implementation
merged the arguments anyway, so all this commit really does is move
the merging up the call stack, and store the merged result rather than
storing the separate parts.
However, the biggest reason for why this commit is needed, is an issue
with passing arguments from GDB to gdbserver when starting a new
inferior.
Consider:
(gdb) set args $VAR
(gdb) run
...
When using a native target the inferior will see the value of $VAR
expanded by the shell GDB uses to start the inferior. However, if
using an extended-remote target the inferior will see literally $VAR,
the unexpanded name of the variable, the reason for this is that,
although GDB sends '$VAR' to gdbserver, when gdbserver receives this,
it converts this to '\$VAR', which prevents the variable from being
expanded by the shell.
The reason for this is that construct_inferior_arguments escapes all
special shell characters within its arguments, and it is
construct_inferior_arguments that is used to combine the separate
arguments into a single string.
In the future I will change construct_inferior_arguments so that
it can apply different escaping strategies. When this happens we will
want to escape arguments coming from the gdbserver command line
differently than arguments coming from GDB (via a vRun packet), which
means we need to call construct_inferior_arguments earlier, at the
point where we know if the arguments came from the gdbserver command
line, or from the vRun packet.
This argument escaping issue is discussed in PR gdb/28392.
This commit doesn't fix any issues, nor does it change
construct_inferior_arguments to actually do different escaping, that
will all come later. This is purely a restructuring.
There should be no user visible changes after this commit.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28392
Tested-By: Guinevere Larsen <guinevere@redhat.com>
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Problem Description
-------------------
On a Windows machine I built gdbserver, configured for the target
'x86_64-w64-mingw32', then on a GNU/Linux machine I built GDB with
support for all target (--enable-targets=all).
On the Windows machine I start gdbserver with a small test binary:
$ gdbserver 192.168.129.25:54321 C:\some\directory\executable.exe
On the GNU/Linux machine I start GDB without the test binary, and
connect to gdbserver.
As I have not given GDB the test binary, my expectation is that GDB
would connect to gdbserver and then download the file over the remote
protocol, but instead I was presented with this message:
(gdb) target remote 192.168.129.25:54321
Remote debugging using 192.168.129.25:54321
warning: C:\some\directory\executable.exe: No such file or directory.
0x00007ffa3e1e1741 in ?? ()
(gdb)
What I found is that if I told GDB where to find the binary, like
this:
(gdb) file target:C:/some/directory/executable.exe
A program is being debugged already.
Are you sure you want to change the file? (y or n) y
Reading C:/some/directory/executable.exe from remote target...
warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead.
Reading C:/some/directory/executable.exe from remote target...
Reading symbols from target:C:/some/directory/executable.exe...
(gdb)
then GDB would download the executable.
The Actual Issue
----------------
I tracked the problem down to exec_file_find (solib.c). The remote
target was passing an absolute Windows filename (beginning with "C:/"
in this case), but in exec_file_find GDB was failing the
IS_TARGET_ABSOLUTE_PATH call, and so was treating the filename as
relative.
The IS_TARGET_ABSOLUTE_PATH call was failing because GDB thought that
the file system kind was "unix", and as the filename didn't start with
a "/" it assumed the filename was not absolute.
But I'm connecting to a Windows target and 'target-file-system-kind'
was set to "auto", so GDB should be figuring out that the target
file-system is "dos-based".
Looking in effective_target_file_system_kind (filesystem.c), we find
that the logic of "auto" is delegated to the current gdbarch. However
in windows-tdep.c we see:
set_gdbarch_has_dos_based_file_system (gdbarch, 1);
So if we are using a Windows gdbarch we should have "dos-based"
filesystems. What this means is that after connecting to the remote
target GDB has selected the wrong gdbarch.
What's happening is that the target description sent back by the
remote target only includes the x86-64 registers. There's no
information about which OS we're on. As a consequence, GDB picks the
first x86-64 gdbarch which can handle the provided register set, which
happens to be a GNU/Linux gdbarch.
And indeed, there doesn't appear to be anywhere in gdbserver that sets
the osabi on the target descriptions. Some target descriptions do have
their osabi set when the description is created, e.g. in:
gdb/arch/amd64.c - Sets GNU/Linux osabi when appropriate.
gdb/arch/i386.c - Likewise.
gdb/arch/tic6x.c - Always set GNU/Linux osabi.
There are also some cases in gdb/features/*.c where the tdesc is set,
but these locations are only called from GDB, not from gdbserver.
This means that many target descriptions are created without an osabi,
gdbserver does nothing to fix this, and the description is returned to
GDB without an osabi included. This leaves GDB having to guess what
the target osabi is, and in some cases, GDB can get this wrong.
Proposed Solution
-----------------
I propose to change init_target_desc so that it requires an gdb_osabi
to be passed in, this will then be used to set the target_desc osabi
field.
I believe that within gdbserver init_target_desc is called for every
target_desc, so this should mean that every target_desc has an
opportunity to set the osabi to something sane.
I did consider passing the osabi into the code which creates the
target_desc objects, but that would require updating far more code, as
each target has its own code for creating target descriptions.
The approach taken here requires minimal changes and forces every
user of init_target_desc to think about what the correct osabi is.
In some cases, e.g. amd64, where the osabi is already set when the
target_desc is created, the init_target_desc call will override the
current value, however, we should always be replacing it with the same
actual value. i.e. if the target_desc is created with the osabi set
to GNU/Linux, then this should only happen when gdbserver is built for
GNU/Linux, in which case the init_target_desc should also be setting
the osabi to GNU/Linux.
The Tricky Bits
---------------
Some targets, like amd64, use a features based approach for creating
target_desc objects, there's a function in arch/amd64.c which creates
a target_desc, adds features too it, and returns the new target_desc.
This target_desc is then passed to an init_target_desc call within
gdbserver. This is the easy case to handle.
Then there are other targets which instead have a fixed set of xml
files, each of which is converted into a .dat file, which is then used
to generate a .cc file, which is compiled into gdbserver. The
generated .cc file creates the target_desc object and calls
init_target_desc on it. In this case though the target description
that is sent to GDB isn't generated from the target_desc object, but
is instead the contents of the fixed xml file. For this case the
osabi which we pass to init_target_desc should match the osabi that
exists in the fixed xml file.
Luckily, in the previous commit I copied the osabi information from
the fixed xml files into the .dat files. So in this commit I have
extended regdat.sh to read the osabi from the .dat file and use it in
the generated init_target_desc call.
The problem with some of these .dat base targets is that their fixed
xml files don't currently contain any osabi information, and the file
names don't indicate that they are Linux only (despite them currently
only being used from gdbserver for Linux targets), so I don't
currently feel confident adding any osabi information to these files.
An example would be features/rs6000/powerpc-64.xml. For now I've just
ignored these cases. The init_target_desc will use GDB_OSABI_UNKNOWN
which is the default. This means that for these targets nothing
changes from the current behaviour. But many other targets do now
pass the osabi back. Targets that do pass the osabi back are
improved with this commit.
Conclusion
----------
Now when I connect to the Windows remote the target description
returned includes the osabi name. With this extra information GDB
selects the correct gdbarch object, which means that GDB understands
the target has a "dos-based" file-system. With that correct GDB
understands that the filename it was given is absolute, and so fetches
the file from the remote as we'd like.
Reviewed-By: Kevin Buettner <kevinb@redhat.com>
This reverts commit 98bcde5e26. This
commit was causing build problems on at least sparc, ppc, and s390,
though I suspect some other targets might be impacted too.
On a Windows machine I built gdbserver, configured for the target
'x86_64-w64-mingw32', then on a GNU/Linux machine I built GDB with
support for all target (--enable-targets=all).
On the Windows machine I start gdbserver with a small test binary:
$ gdbserver 192.168.129.25:54321 C:\some\directory\executable.exe
On the GNU/Linux machine I start GDB without the test binary, and
connect to gdbserver.
As I have not given GDB the test binary, my expectation is that GDB
would connect to gdbserver and then download the file over the remote
protocol, but instead I was presented with this message:
(gdb) target remote 192.168.129.25:54321
Remote debugging using 192.168.129.25:54321
warning: C:\some\directory\executable.exe: No such file or directory.
0x00007ffa3e1e1741 in ?? ()
(gdb)
What I found is that if I told GDB where to find the binary, like
this:
(gdb) file target:C:/some/directory/executable.exe
A program is being debugged already.
Are you sure you want to change the file? (y or n) y
Reading C:/some/directory/executable.exe from remote target...
warning: File transfers from remote targets can be slow. Use "set sysroot" to access files locally instead.
Reading C:/some/directory/executable.exe from remote target...
Reading symbols from target:C:/some/directory/executable.exe...
(gdb)
then GDB would download the executable.
I eventually tracked the problem down to exec_file_find (solib.c).
The remote target was passing an absolute Windows filename (beginning
with "C:/" in this case), but in exec_file_find GDB was failing the
IS_TARGET_ABSOLUTE_PATH call, and so was treating the filename as
relative.
The IS_TARGET_ABSOLUTE_PATH call was failing because GDB thought that
the file system kind was "unix", and as the filename didn't start with
a "/" it assumed the filename was not absolute.
But I'm connecting to a Windows target, my 'target-file-system-kind'
was set to "auto", so should be figuring out that my file-system is
"dos-based".
Looking in effective_target_file_system_kind (filesystem.c), we find
that the logic of "auto" is delegated to the current gdbarch. However
in windows-tdep.c we see:
set_gdbarch_has_dos_based_file_system (gdbarch, 1);
So if we are using a Windows gdbarch we should have "dos-based"
filesystems. What this means is that after connecting to the remote
target GDB has selected the wrong gdbarch.
What's happening is that the target description sent back by the
remote target only includes the x86-64 registers. There's no
information about which OS we're on. As a consequence, GDB picks the
first x86-64 gdbarch which can handle the provided register set, which
happens to be a GNU/Linux gdbarch.
And indeed, there doesn't appear to be anywhere in gdbserver that sets
the osabi on the target descriptions, though some target descriptions
do have their osabi set when the description is created, e.g. in:
gdb/arch/amd64.c - Sets GNU/Linux osabi when appropriate.
gdb/arch/i386.c - Likewise.
gdb/arch/tic6x.c - Always set GNU/Linux osabi.
Most target descriptions are created without an osabi, gdbserver does
nothing to fix this, and the description is returned to GDB without an
osabi included.
I propose that we always set the osabi name on the target descriptions
returned from gdbserver. We could try to do this when the description
is first created, but that would mean passing extra flags into the
tdesc creation code (or just passing the osabi string in), and I don't
think that's really necessary. If we consider the tdesc creation as
being about figuring out which registers are on the target, then it
makes sense that the osabi information is injected later.
So what I've done is require the osabi name to be passed to the
init_target_desc function. This is called, I believe, for all
targets, in the gdbserver code.
Now when I connect to the Windows remote the target description
returned includes the osabi name. With this extra information GDB
selects the correct gdbarch object, which means that GDB understands
the target has a "dos-based" file-system. With that correct GDB
understands that the filename it was given is absolute, and so fetches
the file from the remote as we'd like.
Approved-By: Luis Machado <luis.machado@arm.com>
Approved-By: Simon Marchi <simon.marchi@efficios.com>
This commit is the result of the following actions:
- Running gdb/copyright.py to update all of the copyright headers to
include 2024,
- Manually updating a few files the copyright.py script told me to
update, these files had copyright headers embedded within the
file,
- Regenerating gdbsupport/Makefile.in to refresh it's copyright
date,
- Using grep to find other files that still mentioned 2023. If
these files were updated last year from 2022 to 2023 then I've
updated them this year to 2024.
I'm sure I've probably missed some dates. Feel free to fix them up as
you spot them.
This commit is the result of running the gdb/copyright.py script,
which automated the update of the copyright year range for all
source files managed by the GDB project to be updated to include
year 2023.
When working on windows-nat.c, it's useful to see an error message in
addition to the error number given by GetLastError. This patch moves
strwinerror from gdbserver to gdbsupport, and then updates
windows-nat.c to use it. A couple of minor changes to strwinerror
(constify the return type and use the ARRAY_SIZE macro) are also
included.
This changes windows_process_info to use virtual methods for its
callbacks, and then changes the two clients of this code to subclass
this class to implement the methods.
I considered using CRTP here, but that would require making the new
structures visible to the compilation of of nat/windows-nat.c. This
seemed like a bit of a pain, so I didn't do it.
This change then lets us change all the per-inferior globals to be
members of the new subclass. Note that there can still only be a
single inferior -- currently there's a single global of the new type.
This is just another step toward possibly implementing multi-inferior
for Windows.
It's possible this could be cleaned up further... ideally I'd like to
move more of the data into the base class. However, because gdb
supports Cygwin and gdbserver does not, and because I don't have a way
to build or test Cygwin, larger refactorings are difficult.
On Windows, it is possible to disable ASLR when creating a process.
This patch adds code to do this, and hooks it up to gdb's existing
disable-randomization feature. Because the Windows documentation
cautions that this isn't available on all versions of Windows, the
CreateProcess wrapper function is updated to make the attempt, and
then fall back to the current approach if it fails.
I noticed that gdbserver did not implement pid_to_exec_file for
Windows, while gdb did implement it. This patch moves the code to
nat/windows-nat.c, so that it can be shared. This makes the gdbserver
implementation trivial.
I broke the gdbserver build on x86-64 Windows a little while back.
Previously, I could not build this configuration, but today I found
out that if I configure with:
--host=x86_64-w64-mingw32 --target=x86_64-w64-mingw32
using the Fedora 34 tools, it will in fact build. I'm not certain,
but maybe the gnulib update helped with this.
This patch fixes the build. I'm checking it in.
This commit brings all the changes made by running gdb/copyright.py
as per GDB's Start of New Year Procedure.
For the avoidance of doubt, all changes in this commits were
performed by the script.
I noticed that gdbserver/win32-low.h has an unused declaration. This
code was changed a while ago, but this declaration slipped through.
This patch removes it. Tested by rebuilding.
The support for WinCE was removed with commit 84b300de36 ("gdbserver:
remove support for ARM/WinCE"). There is some leftover code for WinCE
support, guarded by the _WIN32_WCE macro, which I didn't know of at the
time.
I didn't remove the _WIN32_WCE references in the tests, because in
theory we still support the WinCE architecture in GDB (when debugging
remotely). So someone could run a test with that (although I'd be
really surprised).
gdb/ChangeLog:
* nat/windows-nat.c: Remove all code guarded by _WIN32_WCE.
* nat/windows-nat.h: Likewise.
gdbserver/ChangeLog:
* win32-low.cc: Remove all code guarded by _WIN32_WCE.
* win32-low.h: Likewise.
Change-Id: I7a871b897e2135dc195b10690bff2a01d9fac05a
This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...
gdb/ChangeLog
Update copyright year range in copyright header of all GDB files.
When a WOW64 process triggers a breakpoint exception in 64bit code (which
happens when a 64bit gdb calls DebugBreakProcess for a 32bit target),
gdb ignores the breakpoint (because Wow64GetThreadContext can only report
the pc of 32bit code, and there is not int3 at this location).
But if these 64bit breakpoint exceptions are handled as SIGINT, gdb
doesn't check for int3, and always stops the target.
gdb/ChangeLog:
2020-09-23 Hannes Domani <ssbssa@yahoo.de>
* nat/windows-nat.c (handle_exception): Handle 64bit breakpoints
in WOW64 processes as SIGINT.
* nat/windows-nat.h: Make wow64_process a shared variable.
* windows-nat.c: Remove static wow64_process variable.
gdbserver/ChangeLog:
2020-09-23 Hannes Domani <ssbssa@yahoo.de>
* win32-low.cc: Remove local wow64_process variable.
* win32-low.h: Remove local wow64_process variable.
This changes the Windows gdbserver port to implement the
stopped_by_sw_breakpoint target method. This is needed to support
pending stops.
This is a separate patch now, because Pedro suggested splitting it out
for simpler bisecting, in the case that it introduces a bug.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.h (win32_process_target::stopped_by_sw_breakpoint)
(win32_process_target::supports_stopped_by_sw_breakpoint):
Declare.
* win32-low.c (win32_supports_z_point_type): Always handle
Z_PACKET_SW_BP.
(win32_insert_point): Call insert_memory_breakpoint when needed.
(win32_remove_point): Call remove_memory_breakpoint when needed.
(win32_process_target::stopped_by_sw_breakpoint)
(win32_process_target::supports_stopped_by_sw_breakpoint): New
methods.
(win32_target_ops): Update.
(maybe_adjust_pc): New function.
(win32_wait): Call maybe_adjust_pc.
This adds a decr_pc_after_break member to win32_target_ops and updates
the two Windows targets to set it.
Note that I can't test the win32-arm-low.c change.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.h (struct win32_target_ops) <decr_pc_after_break>: New
field.
* win32-i386-low.c (the_low_target): Update.
* win32-arm-low.c (the_low_target): Update.
This changes win32-low.c to implement the read_pc and write_pc
methods. A subsequent patch will need these.
Note that I have no way to test, or even compile, the win32-arm-low.c
change.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.h (win32_process_target::read_pc)
(win32_process_target::write_pc): Declare.
* win32-low.c (win32_process_target::read_pc)
(win32_process_target::write_pc): New methods.
* win32-i386-low.c (i386_win32_get_pc, i386_win32_set_pc): New
functions.
(the_low_target): Update.
* win32-arm-low.c (arm_win32_get_pc, arm_win32_set_pc): New
functions.
(the_low_target): Update.
This introduces a new file, nat/windows-nat.h, which holds the
definition of windows_thread_info. This is now shared between gdb and
gdbserver.
Note that the two implementations different slightly. gdb had a
couple of fields ("name" and "reload_context") that gdbserver did not;
while gdbserver had one field ("base_context") that gdb did not, plus
better comments. The new file preserves all the fields, and the
comments.
gdb/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* windows-nat.c (struct windows_thread_info): Remove.
* nat/windows-nat.h: New file.
gdbserver/ChangeLog
2020-04-08 Tom Tromey <tromey@adacore.com>
* win32-low.h (struct windows_thread_info): Remove.
This is the beginning of a series of patches where the goal is to turn
the target ops vector into a class and all the target op function
pointers into methods of this class.
Currently, the target ops is a struct of function pointers. At the
end of the series, it becomes a class with methods, and the existing
low target definitions become subclasses. That is, we end up with the
following class hierarchy:
process_stratum_target
^
|-- linux-low
|-- lynx-low
|-- nto-low
|-- win32-low
process_stratum_target either defines the default behavior for the
target ops or leaves them as pure virtual for the subclasses to
override.
The transformation is done by first introducing a helper class, called
'process_target', that is initially empty. An instance of this class
is added to the end of the current target ops vector. This new field
is called 'pt'. We will gradually carry target ops to the new class,
one by one, whereas the invocation of the target op will be converted
to a method call on 'pt'.
For instance, target op 'attach' is currently invoked as
(*the_target->attach) (args)
After moving 'attach' as a method to 'process_target', it will be
invoked as
the_target->pt->attach (args)
In this process, the concrete target vector definitions
(e.g. linux-low, win32-low, nto-low, etc.) are turned into derived
classes of 'process_target', so that they can either inherit the
default behavior of the target ops or can override the method.
We prefer to make this transition gradually rather than in a single
giant patch, to yield bite-size patches. The goal is that after each
patch gdbserver will still be buildable and testable.
The general rule of thumb when converting a target op to a method is
this:
(1) If the function call is protected with a NULL-check with an
obvious default behavior, simply implement that default behavior in
the base class (e.g.: supports_non_stop).
(2) If there is no NULL-check guard, the method becomes pure
virtual, and the derived targets are required to implement the method
(e.g.: attach).
(3) If there is a NULL-check but no apparent default behavior, or if
the NULL-check is utilized to populate a feature support packet,
introduce a 'supports_XYZ' method (e.g.: pid_to_exec_file).
The overall strategy is to preserve the existing behavior as much as
possible.
When we're done moving all the target ops into 'process_target', the
target op vector will contain nothing but the field 'pt'. At that
point, the auxiliary class 'process_target' will simply meld into
'process_stratum_target' and the method calls of the form
'the_target->pt->xyz' will be turned into 'the_target->xyz'.
The "linux-low" target has been built and reg-tested on X86_64 Linux
(Ubuntu). The "win32-low" target has been built (but not tested) via
cross-compilation to a x86_64-w64-mingw32 target. The "lynx-low" and
"nto-low" targets were neither built nor tested.
gdbserver/ChangeLog:
2020-02-20 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* target.h (class process_target): New class definition.
(struct process_stratum_target) <pt>: New field with type
'process_target*'.
* linux-low.h (class linux_process_target): Define as a derived
class of 'process_target'.
* linux-low.cc (linux_target_ops): Add a linux_process_target*
as the 'pt' field.
* lynx-low.h (class lynx_process_target): Define as a derived
class of 'process_target'.
* lynx-low.cc (lynx_target_ops): Add a lynx_process_target*
as the 'pt' field.
* nto-low.h (class nto_process_target): Define as a derived
class of 'process_target'.
* nto-low.cc (nto_target_ops): Add an nto_process_target*
as the 'pt' field.
* win32-low.h (class win32_process_target): Define as a derived
class of 'process_target'.
* win32-low.cc (win32_target_ops): Add a win32_process_target*
as the 'pt' field.
This patch moves gdbserver to the top level.
This patch is as close to a pure move as possible -- gdbserver still
builds its own variant of gnulib and gdbsupport. Changing this will
be done in a separate patch.
[v2] Note that, per Simon's review comment, this patch changes the
tree so that gdbserver is not built for or1k or score. This makes
sense, because there is apparently not actually a gdbserver port here.
[v3] This version of the patch also splits out some configury into a
new file, gdbserver/configure.host, so that the top-level configure
script can simply rely on it in order to decide whether gdbserver
should be built.
[v4] This version adds documentation and removes some unnecessary
top-level dependencies.
[v5] Update docs to mention "make all-gdbserver" and change how
top-level configure decides whether to build gdbserver, switching to a
single, shared script.
Tested by the buildbot.
ChangeLog
2020-02-07 Tom Tromey <tom@tromey.com>
Pedro Alves <palves@redhat.com>
* src-release.sh (GDB_SUPPORT_DIRS): Add gdbserver.
* gdbserver: New directory, moved from gdb/gdbserver.
* configure.ac (host_tools): Add gdbserver.
Only build gdbserver on certain systems.
* Makefile.in, configure: Rebuild.
* Makefile.def (host_modules, dependencies): Add gdbserver.
* MAINTAINERS: Add gdbserver.
gdb/ChangeLog
2020-02-07 Tom Tromey <tom@tromey.com>
* README: Update gdbserver documentation.
* gdbserver: Move to top level.
* configure.tgt (build_gdbserver): Remove.
* configure.ac: Remove --enable-gdbserver.
* configure: Rebuild.
* Makefile.in (distclean): Don't mention gdbserver.
Change-Id: I826b7565b54604711dc7a11edea0499cd51ff39e
