In bash I have the following terminal settings:
...
$ stty
speed 38400 baud; line = 0;
-brkint -imaxbel iutf8
...
and then in gdb using the shell command likewise:
...
(gdb) shell stty
speed 38400 baud; line = 0;
-brkint -imaxbel iutf8
(gdb)
...
and likewise using a shell session:
...
(gdb) shell
$ stty
speed 38400 baud; line = 0;
-brkint -imaxbel iutf8
$
...
But in TUI, we get different settings (removed runaway indentation for
readability):
...
(gdb) shell sttyspeed 38400 baud; line = 0;
min = 1; time = 0;
-brkint -icrnl -imaxbel iutf8
-onlcr
-icanon -echo
(gdb)
...
and consequently the shell is not really usable. This is PR tui/18215.
The easiest way to fix this is to just temporarily leave TUI while in the shell,
leaving the output of the commands in CLI mode, but that's a bit confusing.
Fix this (as suggested in the PR) by restoring the initial terminal settings
while in the shell command, such that also in TUI we have:
...
(gdb) shell sttyspeed 38400 baud; line = 0;
-brkint -imaxbel iutf8
(gdb)
...
Tested on x86_64-linux.
Reported-By: Doug Evans <dje@google.com>
Approved-By: Tom Tromey <tom@tromey.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=18215
The "location_completer" function has been available for a long time,
but it was seemingly never used as the completer for the list function.
A quick check through git history shows that a similar completer was
available for the "edit" command but wasn't added to "list" with no
reasoning for it.
I think "list" should use the location_completer, as it is more aware of
the locspec grammar.
Approved-By: Tom Tromey <tom@tromey.com>
This patch introduces a new macro, INIT_GDB_FILE. This is used to
replace the current "_initialize_" idiom when introducing a per-file
initialization function. That is, rather than write:
void _initialize_something ();
void
_initialize_something ()
{
...
}
... now you would write:
INIT_GDB_FILE (something)
{
...
}
The macro handles both the declaration and definition of the function.
The point of this approach is that it makes it harder to accidentally
cause an initializer to be omitted; see commit 2711e475 ("Ensure
cooked_index_entry self-tests are run"). Specifically, the regexp now
used by make-init-c seems harder to trick.
New in v2: un-did some erroneous changes made by the script.
The bulk of this patch was written by script.
Regression tested on x86-64 Fedora 41.
This commit adds filename completion for the shell command part of
the pipe command. This is a follow on from this commit:
commit 036e5c0c91
Date: Mon May 19 20:54:54 2025 +0100
gdb: use quoted filename completion for the shell command
which fixed the completion for the 'shell' command itself.
Like with the 'shell' command, we don't offer completions of command
names pulled from $PATH, we just offer filename completion, which is
often useful for arguments being passed to commands. Maybe in the
future we could add completion for command names too (for both 'pipe'
and the 'shell' command), but that is left for a future commit.
There's some additional testing.
With the quoted filename completion work that I did last year the
deprecated_filename_completer function will now only complete a single
word as a filename, for example:
(gdb) save breakpoints /tm<TAB>
The 'save breakpoints' command uses the deprecated_filename_completer
completion function. In the above '/tm' will complete to '/tmp/' as
expected. However, if you try this:
(gdb) save breakpoints /tmp/ /tm<TAB>
The second '/tm' will not complete for GDB 16.x, but will complete
with GDB 15.x as GDB 15.x is before my changes were merged.
What's actually happening here is that, before my changes, the
filename completion was breaking words on white space, so in the above
the first '/tmp/' and the second '/tm' are seen as separate words for
completion, the second word is therefore seen as the start of a new
filename.
After my changes, deprecated_filename_completer allows spaces to be
part of the filename, so in the above, GDB is actually trying to
complete a filename '/tmp/ /tm' which likely doesn't exist, and so
completion stops.
This change for how deprecated_filename_completer works makes sense,
commands like 'save breakpoints' take their complete command arguments
and treat it as a single filename, so given this:
(gdb) save breakpoints /tmp/ /tm<ENTER>
GDB really will try to save breakpoints to a file called '/tmp/ /tm',
weird as that may seem. How GDB interprets the command arguments
didn't change with my completion patches, I simply brought completion
into line with how GDB interprets the arguments.
The patches I'm talking about here are this set:
* 4076f962e8 gdb: split apart two different types of filename completion
* dc22ab49e9 gdb: deprecated filename_completer and associated functions
* 3503687591 gdb: improve escaping when completing filenames
* 1d1df75397 gdb: move display of completion results into completion_result class
* bbbfe4af4f gdb: simplify completion_result::print_matches
* 2bebc9ee27 gdb: add match formatter mechanism for 'complete' command output
* f2f866c6ca gdb: apply escaping to filenames in 'complete' results
* 8f87fcb1da gdb: improve gdb_rl_find_completion_word for quoted words
* 67b8e30af9 gdb: implement readline rl_directory_rewrite_hook callback
* 1be3b2e82f gdb: extend completion of quoted filenames to work in brkchars phase
* 9dedc2ac71 gdb: fix for completing a second filename for a command
* 4339a3ffc3 gdb: fix filename completion in the middle of a line
Bug PR gdb/32982 identifies a problem with the shell command;
completion broke between 15.x and 16.x. The shell command also uses
deprecated_filename_completer for completion. But consider a shell
command line:
(gdb) shell ls /tm<TAB>
The arguments to the shell command are 'ls /tm' at the point <TAB> is
pressed. Under the old 15.x completion GDB would split the words on
white space and then try to complete '/tm' as a filename.
Under the 16.x model, GDB completes all the arguments as a single
filename, that is 'ls /tm', which is unlikely to match any filenames,
and so completion fails.
The fix is to write a custom completion function for the shell_command
function (cli/cli-cmds.c), this custom completion function will skip
forward to find the last word in the arguments, and then try to
complete that, so in the above example, GDB will skip over 'ls ', and
then tries to complete '/tm', which is exactly what we want.
Given that the filenames passed to the shell command are forwarded to
an actual shell, I have switched over the new quoted filename
completion function for the shell command, this means that white space
within a filename will be escaped with a backslash by the completion
function, which is likely what the user wants, this means the filename
will arrive in the (actual) shell as a single word, rather than
splitting on white space and arriving as two words.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32982
Reviewed-By: Tom Tromey <tom@tromey.com>
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 changes the help command to use the new command style when
displaying text like:
List of "catch" subcommands:
As a side effect, this mildly -- but not hugely -- cleans up some i18n
issues in help_list. The header comment for that function is also
changed to the gdb style.
Finally, this function used to print something like:
Type "help catch" followed by catch subcommand name for full documentation.
The second "catch" here seems redundant to me, so this patch removes
it.
Colors can be specified as "none" for terminal's default color, as a name of
one of the eight standard colors of ISO/IEC 6429 "black", "red", "green", etc.,
as an RGB hexadecimal tripplet #RRGGBB for 24-bit TrueColor, or as an
integer from 0 to 255. Integers 0 to 7 are the synonyms for the standard
colors. Integers 8-15 are used for the so-called bright colors from the
aixterm extended 16-color palette. Integers 16-255 are the indexes into xterm
extended 256-color palette (usually 6x6x6 cube plus gray ramp). In
general, 256-color palette is terminal dependent and sometimes can be
changed with OSC 4 sequences, e.g. "\033]4;1;rgb:00/FF/00\033\\".
It is the responsibility of the user to verify that the terminal supports
the specified colors.
PATCH v5 changes: documentation fixed.
PATCH v6 changes: documentation fixed.
PATCH v7 changes: rebase onto master and fixes after review.
PATCH v8 changes: fixes after review.
We have gdb::handle_eintr, which allows us to rewrite:
...
ssize_t ret;
do
{
errno = 0;
ret = ::write (pipe[1], "+", 1);
}
while (ret == -1 && errno == EINTR);
...
into:
...
ssize_t ret = gdb::handle_eintr (-1, ::write, pipe[1], "+", 1);
...
However, the call to write got a bit mangled, requiring effort to decode it
back to its original form.
Instead, add a new function gdb::write that allows us to write:
...
ssize_t ret = gdb::write (pipe[1], "+", 1);
...
Likewise for waitpid, read and close.
Tested on x86_64-linux.
When disassembling function symbols in C++ code, if GDB is asked to
disassemble a function by name then the function name in the header
line can be demangled by turning on `set print asm-demangle on`, e.g.:
(gdb) disassemble foo_type::some_function
Dump of assembler code for function _ZN8foo_type13some_functionE7my_type:
0x0000000000401142 <+0>: push %rbp
... etc ...
End of assembler dump.
(gdb) set print asm-demangle on
(gdb) disassemble foo_type::some_function
Dump of assembler code for function foo_type::some_function(my_type):
0x0000000000401142 <+0>: push %rbp
... etc ... │
End of assembler dump. │
However, if GDB is disassembling the current function, then this
demangling doesn't work, e.g.:
(gdb) break foo_type::some_function
Breakpoint 1 at 0x401152: file mangle.cc, line 16.
(gdb) run
Starting program: /tmp/mangle
Breakpoint 1, foo_type::some_function (this=0x7fffffffa597, obj=...) at mangle.cc:16
16 obj.update ();
(gdb) disassemble
Dump of assembler code for function _ZN8foo_type13some_functionE7my_type:
0x0000000000401142 <+0>: push %rbp
... etc ...
End of assembler dump.
(gdb) set print asm-demangle on
(gdb) disassemble
Dump of assembler code for function _ZN8foo_type13some_functionE7my_type:
0x0000000000401142 <+0>: push %rbp
... etc ...
End of assembler dump.
This commit fixes this issue, and extends gdb.cp/disasm-func-name.exp,
which was already testing the first case (disassemble by name) to also
cover disassembling the current function.
Approved-By: Tom Tromey <tom@tromey.com>
This patch ensures that all ordinary help strings are wrapped at 80
columns. For the most part this consists of changing code like this
(note the embedded \n and the trailing backslash without a newline):
-Manage the space-separated list of debuginfod server URLs that GDB will query \
-when missing debuginfo, executables or source files.\nThe default value is \
-copied from the DEBUGINFOD_URLS environment variable."),
... to end each line with \n\, like:
+Manage the space-separated list of debuginfod server URLs that GDB will\n\
+query when missing debuginfo, executables or source files.\n\
+The default value is copied from the DEBUGINFOD_URLS environment variable."),
Approved-By: Eli Zaretskii <eliz@gnu.org>
This commit was inspired by this mailing list post:
https://inbox.sourceware.org/gdb-patches/osmtfvf5xe3yx4n7oirukidym4cik7lehhy4re5mxpset2qgwt@6qlboxhqiwgm
When reviewing that patch, the first thing I wanted to do was add some
tests for the 'edit' command because, as far as I can tell, there are
no real tests right now.
The approach I've taken for testing is to override the EDITOR
environment variable, setting this to just 'echo'. Now when the
'edit' command is run, instead of entering an interactive editor, the
shell instead echos back the arguments that GDB is trying to pass to
the editor. The output might look like this:
(gdb) edit
+22 /tmp/gdb/testsuite/gdb.base/edit-cmd.c
(gdb)
We can then test this like any other normal command. I then wrote
some basic tests covering a few situations like, using 'edit' before
the inferior is started. Using 'edit' without any arguments, and
using 'edit' with a line number argument.
There are plenty of cases that are still not tested, for example, the
test program only has a single source file for example. But we can
always add more tests later.
I then used these tests to validate the fix proposed in the above
patch.
The patch above does indeed fix some cases, specifically, when GDB
stops at a location (e.g. a breakpoint location) and then the 'edit'
command without any arguments is fixed. But using the 'list' command
to show some other location, and then 'edit' to edit the just listed
location broken before and after the above patch.
I am instead proposing this alternative patch which I think fixes more
cases. When GDB stops at a location then 'edit' with no arguments
should correctly edit the current line. And using 'list XX' to list a
specific location, followed by 'edit' should also now edit the just
listed location.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=17669
Co-Authored-By: Lluís Batlle i Rossell <viric@viric.name>
Approved-By: Tom Tromey <tom@tromey.com>
When building gdb with -O2 -fsanitize=thread and running test-case
gdb.base/bg-exec-sigint-bp-cond.exp, I run into:
...
(gdb) c&^M
Continuing.^M
(gdb) Quit^M
(gdb) quit_count=1
^M
Breakpoint 2, foo () at bg-exec-sigint-bp-cond.c:23^M
23 return 0;^M
FAIL: $exp: no force memory write: \
SIGINT does not interrupt background execution
...
What happens is that:
- the breakpoint hits
- while evaluating the condition of the breakpoint,
$_shell("kill -INT <pid-of-gdb>") is called, handled by run_under_shell
- in run_under_shell, a vfork is issued
- in the vfork child, execl executes the kill command
- in the vfork parent, waitpid is called to wait for the result of the kill
command
- waitpid returns -1 with errno set to EINTR
- run_under_shell doesn't check the result of waitpid, and returns the
value of local variable status. Since waitpid returned -1, status was
not assigned a value, so it's uninitialized, and happens to be
non-zero
- the breakpoint condition evaluates to true, because
$_shell("kill -INT <pid-of-gdb>") != 0
- the breakpoint triggers a stop, which the test-case doesn't expect.
Fix this by using gdb::handle_eintr to call waitpid in run_under_shell.
Also handle the case that waitpid returns an error other than EINTR, using
perror_with_name.
Tested on x86_64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
PR gdb/30695
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30695
While looking at the recent line number styling commit I noticed a few
places where we could add more file name styling. So lets do that.
Approved-By: Tom Tromey <tom@tromey.com>
This patch adds separate styling for line numbers. That is, whenever
gdb prints a source line number, it uses this style.
v2 includes a change to ensure that %ps works in query.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Reviewed-by: Keith Seitz <keiths@redhat.com>
Some of the gdb and testsuite files double include some headers. While
all headers use include guards, it helps a bit keeping the code base
tidy.
No functional change.
Approved-by: Kevin Buettner <kevinb@redhat.com>
This commit moves the printing of the 'complete' command results out
of the 'complete_command' function. The printing is now done in a new
member function 'completion_result::print_matches'. At this point,
this is entirely a refactor.
The motivation for this refactor is how 'complete' should print the
completion of filename arguments. In some cases the filename results
need to have escaping added to the output. This escaping needs to be
done immediately prior to printing the result as adding too early will
result in multiple 'complete' results potentially being sorted
incorrectly. See the subsequent commits for more details.
There should be no user visible changes after this commit.
Approved-By: Tom Tromey <tom@tromey.com>
Following on from the previous commit, this commit marks the old
unquoted filename completion related functions as deprecated.
The aim of doing this is to make it more obvious to someone adding a
new command that they should not be using the older unquoted style
filename argument handling.
I split this change from the previous to make for an easier review.
This commit touches more files, but is _just_ function renaming.
Check out gdb/completer.{c,h} for what has been renamed. All the
other files have just been updated to use the new names.
There should be no user visible changes after this commit.
Make the current program space reference bubble up one level.
Change-Id: I6ba6dc4a2cb188720cbb61b84ab5c954aac105c6
Approved-By: Tom Tromey <tom@tromey.com>
Reviewed-By: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Make the current program space reference bubble up one level.
Change-Id: I19c4fc2ca955f9c828ef426a077b43983865697b
Approved-By: Tom Tromey <tom@tromey.com>
Reviewed-By: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Make the current program space reference bubble up one level.
Change-Id: I692554474d17e4f4708fd8ad662bf6c0bb964726
Approved-By: Tom Tromey <tom@tromey.com>
Reviewed-By: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Remove some includes reported as unused by clangd. Add some includes in
other files that were previously relying on the transitive include.
Change-Id: Ibdd0a998b04d21362a20d0ca8e5267e21e2e133e
Currently, when a user tries to list the current location, there are 2
different error messages that can happen, either:
(gdb) list .
No symbol table is loaded. Use the "file" command.
or
(gdb) list .
No debug information available to print source lines.
The difference here is if gdb can find any symtabs at all or not, which
is not something too important for end-users - and isn't informative at
all. This commit changes it so that the error always says that there
isn't debug information available, with these two variants:
(gdb) list .
Insufficient debug info for showing source lines at current PC (0x55555555511d).
or
(gdb) list .
Insufficient debug info for showing source lines at default location.
The difference now is if the inferior has started already, which is
controlled by the user and may be useful.
Unfortunately, it isn't as easy to differentiate if the symtab found for
other list parameters is correct, so other invocations, such as "list +"
still retain their original error message.
Co-Authored-By: Simon Marchi <simark@simark.ca>
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Andrew Burgess <aburgess@redhat.com>
Most files including gdbcmd.h currently rely on it to access things
actually declared in cli/cli-cmds.h (setlist, showlist, etc). To make
things easy, replace all includes of gdbcmd.h with includes of
cli/cli-cmds.h. This might lead to some unused includes of
cli/cli-cmds.h, but it's harmless, and much faster than going through
the 170 or so files by hand.
Change-Id: I11f884d4d616c12c05f395c98bbc2892950fb00f
Approved-By: Tom Tromey <tom@tromey.com>
Now that defs.h, server.h and common-defs.h are included via the
`-include` option, it is no longer necessary for source files to include
them. Remove all the inclusions of these files I could find. Update
the generation scripts where relevant.
Change-Id: Ia026cff269c1b7ae7386dd3619bc9bb6a5332837
Approved-By: Pedro Alves <pedro@palves.net>
When a user attempts to use the "list ." command with an inferior that
doesn't have debug symbols, GDB would crash. This was reported as PR
gdb/31256.
The crash would happen when attempting to get the current symtab_and_line
for the stop location, because the symtab would return a null pointer
and we'd attempt to dereference it to print the line.
This commit fixes that by checking for an empty symtab and erroring out
of the function if it happens.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31256
Approved-By: Tom Tromey <tom@tromey.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.
Since GDB now requires C++17, we don't need the internally maintained
gdb::optional implementation. This patch does the following replacing:
- gdb::optional -> std::optional
- gdb::in_place -> std::in_place
- #include "gdbsupport/gdb_optional.h" -> #include <optional>
This change has mostly been done automatically. One exception is
gdbsupport/thread-pool.* which did not use the gdb:: prefix as it
already lives in the gdb namespace.
Change-Id: I19a92fa03e89637bab136c72e34fd351524f65e9
Approved-By: Tom Tromey <tom@tromey.com>
Approved-By: Pedro Alves <pedro@palves.net>
Add a new command completer function for the disassemble command.
There are two things that this completion function changes. First,
after the previous commit, the new function calls skip_over_slash_fmt,
which means that hitting tab after entering a /OPT flag now inserts a
space ready to start typing the address to disassemble at:
(gdb) disassemble /r<TAB>
(gdb) disassemble /r <CURSOR>
But also, we now get symbol completion after a /OPT option set,
previously this would do nothing:
(gdb) disassemble /r mai<TAB>
But now:
(gdb) disassemble /r mai<TAB>
(gdb) disassemble /r main <CURSOR>
Which was my main motivation for working on this commit.
However, I have made a second change in the completion function.
Currently, the disassemble command calls the generic
location_completer function, however, the disassemble docs say:
Note that the 'disassemble' command's address arguments are specified
using expressions in your programming language (*note Expressions:
Expressions.), not location specs (*note Location Specifications::).
So, for example, if you want to disassemble function 'bar' in file
'foo.c', you must type 'disassemble 'foo.c'::bar' and not 'disassemble
foo.c:bar'.
And indeed, if I try:
(gdb) disassemble hello.c:main
No symbol "hello" in current context.
(gdb) disassemble hello.c::main
No symbol "hello" in current context.
(gdb) disassemble 'hello.c'::main
Dump of assembler code for function main:
... snip ...
But, if I do this:
(gdb) disassemble hell<TAB>
(gdb) disassemble hello.c:<CURSOR>
which is a consequence of using the location_completer function. So
in this commit, after calling skip_over_slash_fmt, I forward the bulk
of the disassemble command completion to expression_completer. Now
when I try this:
(gdb) disassemble hell<TAB>
gives nothing, which I think is an improvement. There is one slight
disappointment, if I do:
(gdb) disassemble 'hell<TAB>
I still get nothing. I had hoped that this would expand to:
'hello.c':: but I guess this is a limitation of the current
expression_completer implementation, however, I don't think this is a
regression, the previous expansion was just wrong. Fixing
expression_completer is out of scope for this commit.
I've added some disassembler command completion tests, and also a test
that disassembling using 'FILE'::FUNC syntax works, as I don't think
that is tested anywhere.
The disassembler gained a new /b flag in this commit:
commit d4ce49b7ac
Date: Tue Jun 21 20:23:35 2022 +0100
gdb: disassembler opcode display formatting
The /b and /r flags result in the instruction opcodes displayed in
different formats, so it's not possible to have both at the same
time. Currently the /b flag overrides the /r flag.
We have a similar situation with the /m and /s flags, but here, if the
user tries to use both flags then they will get an error.
I think the error is clearer, so in this commit I propose that we add
an error if /r and /b are both used.
Obviously this change breaks backwards compatibility. I don't have a
compelling argument for why we should make the change beyond my
feeling that it was a mistake not to add this error from the start,
and that the new behaviour is better.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
I noticed a comment by an include and remembered that I think these
don't really provide much value -- sometimes they are just editorial,
and sometimes they are obsolete. I think it's better to just remove
them. Tested by rebuilding.
Approved-By: Andrew Burgess <aburgess@redhat.com>
After the series that added this command was pushed, Pedro mentioned
that the news description could easily be misinterpreted, as well as
some code and test improvements that should be made.
While fixing the test, I realized that code repetition wasn't
happening as it should, so I took care of that too.
Approved-By: Andrew Burgess <aburgess@redhat.com>
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
The command 'list' has accepted the argument '+' for many years already,
but this option wasn't documented either in the texinfo docs or in the
help text for the command. This commit documents it.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>
When using "list" with no arguments, GDB will first print the lines
around where the inferior is stopped, then print the next N lines until
reaching the end of file, at which point it warns the user "Line X out
of range, file Y only has X-1 lines.". This is usually desirable, but
if the user can no longer see the original line, they may have forgotten
the current line or that a list command was used at all, making GDB's
error message look cryptic. It was reported in bugzilla as PR cli/30497.
This commit improves the user experience by changing the behavior of
"list" slightly when a user passes no arguments. It now prints that the
end of the file has been reached and recommends that the user use the
command "list ." instead.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30497
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>
Currently, after the user has used the list command once, there is no
self-contained way to ask GDB to print the location where the inferior is
stopped. The current best options require either using a separate
command to scope out where the inferior is stopped, or using "list *$pc"
requiring knowledge of GDB standard registers. This commit adds a way
to do that using '.' as a new argument for the 'list' command. If the
inferior isn't running, the command prints around the main function.
Because this necessitated having the inferior running and the test was
(seemingly unnecessarily) using printf in a non-essential way and it
would make the resulting log harder to read for no benefit, it was
replaced by a different statement.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>
A future patch will add more situations that calculates "lines around a
certain point" to be printed using print_source_lines, and the logic
could be re-used. As a preparation for those commits, this one factors
out that part of the logic of the list command into its own function.
No functional changes are expected
Approved-By: Tom Tromey <tom@tromey.com>
After this commit:
commit baab375361
Date: Tue Jul 13 14:44:27 2021 -0400
gdb: building inferior strings from within GDB
It was pointed out that a new ASan failure had been introduced which
was triggered by gdb.base/internal-string-values.exp:
(gdb) PASS: gdb.base/internal-string-values.exp: test_setting: all langs: lang=ada: ptype "foo"
print $_gdb_maint_setting("test-settings string")
=================================================================
==80377==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000068034 at pc 0x564785cba682 bp 0x7ffd20644620 sp 0x7ffd20644610
READ of size 1 at 0x603000068034 thread T0
#0 0x564785cba681 in find_command_name_length(char const*) /tmp/src/binutils-gdb/gdb/cli/cli-decode.c:2129
#1 0x564785cbacb2 in lookup_cmd_1(char const**, cmd_list_element*, cmd_list_element**, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, int, bool) /tmp/src/binutils-gdb/gdb/cli/cli-decode.c:2186
#2 0x564785cbb539 in lookup_cmd_1(char const**, cmd_list_element*, cmd_list_element**, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, int, bool) /tmp/src/binutils-gdb/gdb/cli/cli-decode.c:2248
#3 0x564785cbbcf3 in lookup_cmd(char const**, cmd_list_element*, char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*, int, int) /tmp/src/binutils-gdb/gdb/cli/cli-decode.c:2339
#4 0x564785c82df2 in setting_cmd /tmp/src/binutils-gdb/gdb/cli/cli-cmds.c:2219
#5 0x564785c84274 in gdb_maint_setting_internal_fn /tmp/src/binutils-gdb/gdb/cli/cli-cmds.c:2348
#6 0x564788167b3b in call_internal_function(gdbarch*, language_defn const*, value*, int, value**) /tmp/src/binutils-gdb/gdb/value.c:2321
#7 0x5647854b6ebd in expr::ada_funcall_operation::evaluate(type*, expression*, noside) /tmp/src/binutils-gdb/gdb/ada-lang.c:11254
#8 0x564786658266 in expression::evaluate(type*, noside) /tmp/src/binutils-gdb/gdb/eval.c:111
#9 0x5647871242d6 in process_print_command_args /tmp/src/binutils-gdb/gdb/printcmd.c:1322
#10 0x5647871244b3 in print_command_1 /tmp/src/binutils-gdb/gdb/printcmd.c:1335
#11 0x564787125384 in print_command /tmp/src/binutils-gdb/gdb/printcmd.c:1468
#12 0x564785caac44 in do_simple_func /tmp/src/binutils-gdb/gdb/cli/cli-decode.c:95
#13 0x564785cc18f0 in cmd_func(cmd_list_element*, char const*, int) /tmp/src/binutils-gdb/gdb/cli/cli-decode.c:2735
#14 0x564787c70c68 in execute_command(char const*, int) /tmp/src/binutils-gdb/gdb/top.c:574
#15 0x564786686180 in command_handler(char const*) /tmp/src/binutils-gdb/gdb/event-top.c:543
#16 0x56478668752f in command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) /tmp/src/binutils-gdb/gdb/event-top.c:779
#17 0x564787dcb29a in tui_command_line_handler /tmp/src/binutils-gdb/gdb/tui/tui-interp.c:104
#18 0x56478668443d in gdb_rl_callback_handler /tmp/src/binutils-gdb/gdb/event-top.c:250
#19 0x7f4efd506246 in rl_callback_read_char (/usr/lib/libreadline.so.8+0x3b246) (BuildId: 092e91fc4361b0ef94561e3ae03a75f69398acbb)
#20 0x564786683dea in gdb_rl_callback_read_char_wrapper_noexcept /tmp/src/binutils-gdb/gdb/event-top.c:192
#21 0x564786684042 in gdb_rl_callback_read_char_wrapper /tmp/src/binutils-gdb/gdb/event-top.c:225
#22 0x564787f1b119 in stdin_event_handler /tmp/src/binutils-gdb/gdb/ui.c:155
#23 0x56478862438d in handle_file_event /tmp/src/binutils-gdb/gdbsupport/event-loop.cc:573
#24 0x564788624d23 in gdb_wait_for_event /tmp/src/binutils-gdb/gdbsupport/event-loop.cc:694
#25 0x56478862297c in gdb_do_one_event(int) /tmp/src/binutils-gdb/gdbsupport/event-loop.cc:264
#26 0x564786df99f0 in start_event_loop /tmp/src/binutils-gdb/gdb/main.c:412
#27 0x564786dfa069 in captured_command_loop /tmp/src/binutils-gdb/gdb/main.c:476
#28 0x564786dff61f in captured_main /tmp/src/binutils-gdb/gdb/main.c:1320
#29 0x564786dff75c in gdb_main(captured_main_args*) /tmp/src/binutils-gdb/gdb/main.c:1339
#30 0x564785381b6d in main /tmp/src/binutils-gdb/gdb/gdb.c:32
#31 0x7f4efbc3984f (/usr/lib/libc.so.6+0x2384f) (BuildId: 2f005a79cd1a8e385972f5a102f16adba414d75e)
#32 0x7f4efbc39909 in __libc_start_main (/usr/lib/libc.so.6+0x23909) (BuildId: 2f005a79cd1a8e385972f5a102f16adba414d75e)
#33 0x564785381934 in _start (/tmp/build/binutils-gdb/gdb/gdb+0xabc5934) (BuildId: 90de353ac158646e7dab501b76a18a76628fca33)
0x603000068034 is located 0 bytes after 20-byte region [0x603000068020,0x603000068034) allocated by thread T0 here:
#0 0x7f4efcee0cd1 in __interceptor_calloc /usr/src/debug/gcc/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77
#1 0x5647856265d8 in xcalloc /tmp/src/binutils-gdb/gdb/alloc.c:97
#2 0x564788610c6b in xzalloc(unsigned long) /tmp/src/binutils-gdb/gdbsupport/common-utils.cc:29
#3 0x56478815721a in value::allocate_contents(bool) /tmp/src/binutils-gdb/gdb/value.c:929
#4 0x564788157285 in value::allocate(type*, bool) /tmp/src/binutils-gdb/gdb/value.c:941
#5 0x56478815733a in value::allocate(type*) /tmp/src/binutils-gdb/gdb/value.c:951
#6 0x5647854ae81c in expr::ada_string_operation::evaluate(type*, expression*, noside) /tmp/src/binutils-gdb/gdb/ada-lang.c:10675
#7 0x5647854b63b8 in expr::ada_funcall_operation::evaluate(type*, expression*, noside) /tmp/src/binutils-gdb/gdb/ada-lang.c:11184
#8 0x564786658266 in expression::evaluate(type*, noside) /tmp/src/binutils-gdb/gdb/eval.c:111
#9 0x5647871242d6 in process_print_command_args /tmp/src/binutils-gdb/gdb/printcmd.c:1322
#10 0x5647871244b3 in print_command_1 /tmp/src/binutils-gdb/gdb/printcmd.c:1335
#11 0x564787125384 in print_command /tmp/src/binutils-gdb/gdb/printcmd.c:1468
#12 0x564785caac44 in do_simple_func /tmp/src/binutils-gdb/gdb/cli/cli-decode.c:95
#13 0x564785cc18f0 in cmd_func(cmd_list_element*, char const*, int) /tmp/src/binutils-gdb/gdb/cli/cli-decode.c:2735
#14 0x564787c70c68 in execute_command(char const*, int) /tmp/src/binutils-gdb/gdb/top.c:574
#15 0x564786686180 in command_handler(char const*) /tmp/src/binutils-gdb/gdb/event-top.c:543
#16 0x56478668752f in command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) /tmp/src/binutils-gdb/gdb/event-top.c:779
#17 0x564787dcb29a in tui_command_line_handler /tmp/src/binutils-gdb/gdb/tui/tui-interp.c:104
#18 0x56478668443d in gdb_rl_callback_handler /tmp/src/binutils-gdb/gdb/event-top.c:250
#19 0x7f4efd506246 in rl_callback_read_char (/usr/lib/libreadline.so.8+0x3b246) (BuildId: 092e91fc4361b0ef94561e3ae03a75f69398acbb)
The problem is in cli/cli-cmds.c, in the function setting_cmd, where
we do this:
const char *a0 = (const char *) argv[0]->contents ().data ();
Here argv[0] is a value* which we know is either a TYPE_CODE_ARRAY or
a TYPE_CODE_STRING. The problem is that the above line is casting the
value contents directly to a C-string, i.e. one that is assumed to
have a null-terminator at the end.
After the above commit this can no longer be assumed to be true. A
string value will be represented just as it would be in the current
language, so for Ada and Fortran the string will be an array of
characters with no null-terminator at the end.
My proposed solution is to copy the string contents into a std::string
object, and then use the std::string::c_str() value, this will ensure
that a null-terminator has been added.
I had a check through GDB at places TYPE_CODE_STRING was used and
couldn't see any other obvious places where this type of assumption
was being made, so hopefully this is the only offender.
Running the above test with ASan compiled in no longer gives an error.
Reviewed-By: Tom Tromey <tom@tromey.com>
History Of This Patch
=====================
This commit aims to address PR gdb/21699. There have now been a
couple of attempts to fix this issue. Simon originally posted two
patches back in 2021:
https://sourceware.org/pipermail/gdb-patches/2021-July/180894.htmlhttps://sourceware.org/pipermail/gdb-patches/2021-July/180896.html
Before Pedro then posted a version of his own:
https://sourceware.org/pipermail/gdb-patches/2021-July/180970.html
After this the conversation halted. Then in 2023 I (Andrew) also took
a look at this bug and posted two versions:
https://sourceware.org/pipermail/gdb-patches/2023-April/198570.htmlhttps://sourceware.org/pipermail/gdb-patches/2023-April/198680.html
The approach taken in my first patch was pretty similar to what Simon
originally posted back in 2021. My second attempt was only a slight
variation on the first.
Pedro then pointed out his older patch, and so we arrive at this
patch. The GDB changes here are mostly Pedro's work, but updated by
me (Andrew), any mistakes are mine.
The tests here are a combinations of everyone's work, and the commit
message is new, but copies bits from everyone's earlier work.
Problem Description
===================
Bug PR gdb/21699 makes the observation that using $_as_string with
GDB's printf can cause GDB to print unexpected data from the
inferior. The reproducer is pretty simple:
#include <stddef.h>
static char arena[100];
/* Override malloc() so value_coerce_to_target() gets a known
pointer, and we know we"ll see an error if $_as_string() gives
a string that isn't null terminated. */
void
*malloc (size_t size)
{
memset (arena, 'x', sizeof (arena));
if (size > sizeof (arena))
return NULL;
return arena;
}
int
main ()
{
return 0;
}
And then in a GDB session:
$ gdb -q test
Reading symbols from /tmp/test...
(gdb) start
Temporary breakpoint 1 at 0x4004c8: file test.c, line 17.
Starting program: /tmp/test
Temporary breakpoint 1, main () at test.c:17
17 return 0;
(gdb) printf "%s\n", $_as_string("hello")
"hello"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
(gdb) quit
The problem above is caused by how value_cstring is used within
py-value.c, but once we understand the issue then it turns out that
value_cstring is used in an unexpected way in many places within GDB.
Within py-value.c we have a null-terminated C-style string. We then
pass a pointer to this string, along with the length of this
string (so not including the null-character) to value_cstring.
In value_cstring GDB allocates an array value of the given character
type, and copies in requested number of characters. However
value_cstring does not add a null-character of its own. This means
that the value created by calling value_cstring is only
null-terminated if the null-character is included in the passed in
length. In py-value.c this is not the case, and indeed, in most uses
of value_cstring, this is not the case.
When GDB tries to print one of these strings the value contents are
pushed to the inferior, and then read back as a C-style string, that
is, GDB reads inferior memory until it finds a null-terminator. For
the py-value.c case, no null-terminator is pushed into the inferior,
so GDB will continue reading inferior memory until a null-terminator
is found, with unpredictable results.
Patch Description
=================
The first thing this patch does is better define what the arguments
for the two function value_cstring and value_string should represent.
The comments in the header file are updated to describe whether the
length argument should, or should not, include a null-character.
Also, the data argument is changed to type gdb_byte. The functions as
they currently exist will handle wide-characters, in which case more
than one 'char' would be needed for each character. As such using
gdb_byte seems to make more sense.
To avoid adding casts throughout GDB, I've also added an overload that
still takes a 'char *', but asserts that the character type being used
is of size '1'.
The value_cstring function is now responsible for adding a null
character at the end of the string value it creates.
However, once we start looking at how value_cstring is used, we
realise there's another, related, problem. Not every language's
strings are null terminated. Fortran and Ada strings, for example,
are just an array of characters, GDB already has the function
value_string which can be used to create such values.
Consider this example using current GDB:
(gdb) set language ada
(gdb) p $_gdb_setting("arch")
$1 = (97, 117, 116, 111)
(gdb) ptype $
type = array (1 .. 4) of char
(gdb) p $_gdb_maint_setting("test-settings string")
$2 = (0)
(gdb) ptype $
type = array (1 .. 1) of char
This shows two problems, first, the $_gdb_setting and
$_gdb_maint_setting functions are calling value_cstring using the
builtin_char character, rather than a language appropriate type. In
the first call, the 'arch' case, the value_cstring call doesn't
include the null character, so the returned array only contains the
expected characters. But, in the $_gdb_maint_setting example we do
end up including the null-character, even though this is not expected
for Ada strings.
This commit adds a new language method language_defn::value_string,
this function takes a pointer and length and creates a language
appropriate value that represents the string. For C, C++, etc this
will be a null-terminated string (by calling value_cstring), and for
Fortran and Ada this can be a bounded array of characters with no null
terminator. Additionally, this new language_defn::value_string
function is responsible for selecting a language appropriate character
type.
After this commit the only calls to value_cstring are from the C
expression evaluator and from the default language_defn::value_string.
And the only calls to value_string are from Fortan, Ada, and ObjectC
related code.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=21699
Co-Authored-By: Simon Marchi <simon.marchi@efficios.com>
Co-Authored-By: Andrew Burgess <aburgess@redhat.com>
Co-Authored-By: Pedro Alves <pedro@palves.net>
Approved-By: Simon Marchi <simon.marchi@efficios.com>
I spotted this behaviour:
(gdb) p $_gdb_maint_setting("xxx")
First argument of $_gdb_maint_setting must be a valid setting of the 'show' command.
Notice that GDB claims I need to use a setting from the 'show'
command, which isn't correct for $_gdb_maint_setting, in this case I
need to use a setting from 'maintenance show'.
This same issue is present for $_gdb_maint_setting_str.
This commit fixes this minor issue.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
I'd like to move some things so they become methods on struct ui. But
first, I think that struct ui and the related things are big enough to
deserve their own file, instead of being scattered through top.{c,h} and
event-top.c.
Change-Id: I15594269ace61fd76ef80a7b58f51ff3ab6979bc
I noticed the prefix parameter was unused in print_doc_of_command. And
when removing it, it becomes unused in apropos_cmd.
Change-Id: Id72980b03fe091b22931e6b85945f412b274ed5e
For testing a following patch, I wanted a way to send a SIGINT to GDB
from a breakpoint condition. And I didn't want to do it from a Python
breakpoint or Python function, as I wanted to exercise non-Python code
paths. So I thought I'd add a new $_shell internal function, that
runs a command under the shell, and returns the exit code. With this,
I could write:
(gdb) b foo if $_shell("kill -SIGINT $gdb_pid") != 0 || <other condition>
I think this is generally useful, hence I'm proposing it here.
Here's the new function in action:
(gdb) p $_shell("true")
$1 = 0
(gdb) p $_shell("false")
$2 = 1
(gdb) p $_shell("echo hello")
hello
$3 = 0
(gdb) p $_shell("foobar")
bash: line 1: foobar: command not found
$4 = 127
(gdb) help function _shell
$_shell - execute a shell command and returns the result.
Usage: $_shell (command)
Returns the command's exit code: zero on success, non-zero otherwise.
(gdb)
NEWS and manual changes included.
Approved-By: Andrew Burgess <aburgess@redhat.com>
Approved-By: Tom Tromey <tom@tromey.com>
Approved-By: Eli Zaretskii <eliz@gnu.org>
Change-Id: I7e36d451ee6b428cbf41fded415ae2d6b4efaa4e
This turns the remaining value_contents functions -- value_contents,
value_contents_all, value_contents_for_printing, and
value_contents_for_printing_const -- into methods of value. It also
converts the static functions require_not_optimized_out and
require_available to be private methods.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Rather than just `unlimited' allow the integer set commands (or command
options) to define arbitrary keywords for the user to use, removing
hardcoded arrangements for the `unlimited' keyword.
Remove the confusingly named `var_zinteger', `var_zuinteger' and
`var_zuinteger_unlimited' `set'/`show' command variable types redefining
them in terms of `var_uinteger', `var_integer' and `var_pinteger', which
have the range of [0;UINT_MAX], [INT_MIN;INT_MAX], and [0;INT_MAX] each.
Following existing practice `var_pinteger' allows extra negative values
to be used, however unlike `var_zuinteger_unlimited' any number of such
values can be defined rather than just `-1'.
The "p" in `var_pinteger' stands for "positive", for the lack of a more
appropriate unambiguous letter, even though 0 obviously is not positive;
"n" would be confusing as to whether it stands for "non-negative" or
"negative".
Add a new structure, `literal_def', the entries of which define extra
keywords allowed for a command and numerical values they correspond to.
Those values are not verified against the basic range supported by the
underlying variable type, allowing extra values to be allowed outside
that range, which may or may not be individually made visible to the
user. An optional value translation is possible with the structure to
follow the existing practice for some commands where user-entered 0 is
internally translated to UINT_MAX or INT_MAX. Such translation can now
be arbitrary. Literals defined by this structure are automatically used
for completion as necessary.
So for example:
const literal_def integer_unlimited_literals[] =
{
{ "unlimited", INT_MAX, 0 },
{ nullptr }
};
defines an extra `unlimited' keyword and a user-visible 0 value, both of
which get translated to INT_MAX for the setting to be used with.
Similarly:
const literal_def zuinteger_unlimited_literals[] =
{
{ "unlimited", -1, -1 },
{ nullptr }
};
defines the same keyword and a corresponding user-visible -1 value that
is used for the requested setting. If the last member were omitted (or
set to `{}') here, then only the keyword would be allowed for the user
to enter and while -1 would still be used internally trying to enter it
as a part of a command would result in an "integer -1 out of range"
error.
Use said error message in all cases (citing the invalid value requested)
replacing "only -1 is allowed to set as unlimited" previously used for
`var_zuinteger_unlimited' settings only rather than propagating it to
`var_pinteger' type. It could only be used for the specific case where
a single extra `unlimited' keyword was defined standing for -1 and the
use of numeric equivalents is discouraged anyway as it is for historical
reasons only that they expose GDB internals, confusingly different
across variable types. Similarly update the "must be >= -1" Guile error
message.
Redefine Guile and Python parameter types in terms of the new variable
types and interpret extra keywords as Scheme keywords and Python strings
used to communicate corresponding parameter values. Do not add a new
PARAM_INTEGER Guile parameter type, however do handle the `var_integer'
variable type now, permitting existing parameters defined by GDB proper,
such as `listsize', to be accessed from Scheme code.
With these changes in place it should be trivial for a Scheme or Python
programmer to expand the syntax of the `make-parameter' command and the
`gdb.Parameter' class initializer to have arbitrary extra literals along
with their internal representation supplied.
Update the testsuite accordingly.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
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.
Consider a hello world a.out, started using gdbserver:
...
$ gdbserver --once 127.0.0.1:2345 ./a.out
Process ./a.out created; pid = 15743
Listening on port 2345
...
that we can connect to using gdb:
...
$ gdb -ex "target remote 127.0.0.1:2345"
Remote debugging using 127.0.0.1:2345
Reading /home/vries/a.out from remote target...
...
0x00007ffff7dd4550 in _start () from target:/lib64/ld-linux-x86-64.so.2
(gdb)
...
After that, we can for instance quit with confirmation:
...
(gdb) quit
A debugging session is active.
Inferior 1 [process 16691] will be killed.
Quit anyway? (y or n) y
$
...
Or, kill with confirmation and quit:
...
(gdb) kill
Kill the program being debugged? (y or n) y
[Inferior 1 (process 16829) killed]
(gdb) quit
$
...
Or, monitor exit, kill with confirmation, and quit:
...
(gdb) monitor exit
(gdb) kill
Kill the program being debugged? (y or n) y
Remote connection closed
(gdb) quit
$
...
But when doing monitor exit followed by quit with confirmation, we get the gdb
prompt back, requiring us to do quit once more:
...
(gdb) monitor exit
(gdb) quit
A debugging session is active.
Inferior 1 [process 16944] will be killed.
Quit anyway? (y or n) y
Remote connection closed
(gdb) quit
$
...
So, the first quit didn't quit. This happens as follows:
- quit_command calls query_if_trace_running
- a TARGET_CLOSE_ERROR is thrown
- it's caught in remote_target::get_trace_status, but then
rethrown because it's TARGET_CLOSE_ERROR
- catch_command_errors catches the error, at which point the quit command
has been aborted.
The TARGET_CLOSE_ERROR is defined as:
...
/* Target throwing an error has been closed. Current command should be
aborted as the inferior state is no longer valid. */
TARGET_CLOSE_ERROR,
...
so in a way this is expected behaviour. But aborting quit because the inferior
state (which we've already confirmed we're not interested in) is no longer
valid, and having to type quit again seems pointless.
Furthermore, the purpose of not catching errors thrown by
query_if_trace_running as per commit 2f9d54cfce ("make -gdb-exit call
disconnect_tracing too, and don't lose history if the target errors on
"quit""), was to make sure that error (_("Not confirmed.") had effect.
Fix this in quit_command by catching only the TARGET_CLOSE_ERROR exception
during query_if_trace_running and reporting it:
...
(gdb) monitor exit
(gdb) quit
A debugging session is active.
Inferior 1 [process 19219] will be killed.
Quit anyway? (y or n) y
Remote connection closed
$
...
Tested on x86_64-linux.
PR server/15746
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=15746
Approved-By: Tom Tromey <tom@tromey.com>
