When a GDB built with -D_GLIBCXX_DEBUG=1 reads a binary with a single
character name, we hit this assertion failure:
$ ./gdb -q --data-directory=data-directory -nx ./x
/usr/include/c++/12.1.0/string_view:239: constexpr const std::basic_string_view<_CharT, _Traits>::value_type& std::basic_string_view<_CharT, _Traits>::operator[](size_type) const [with _CharT = char; _Traits = std::char_traits<char>; const_reference = const char&; size_type = long unsigned int]: Assertion '__pos < this->_M_len' failed.
The backtrace:
#3 0x00007ffff6c0f002 in std::__glibcxx_assert_fail (file=<optimized out>, line=<optimized out>, function=<optimized out>, condition=<optimized out>) at /usr/src/debug/gcc/libstdc++-v3/src/c++11/debug.cc:60
#4 0x000055555da8a864 in std::basic_string_view<char, std::char_traits<char> >::operator[] (this=0x7fffffffcc30, __pos=1) at /usr/include/c++/12.1.0/string_view:239
#5 0x00005555609dcb88 in path_join[abi:cxx11](gdb::array_view<std::basic_string_view<char, std::char_traits<char> > const>) (paths=...) at /home/simark/src/binutils-gdb/gdbsupport/pathstuff.cc:203
#6 0x000055555e0443f4 in path_join<char const*, char const*> () at /home/simark/src/binutils-gdb/gdb/../gdbsupport/pathstuff.h:84
#7 0x00005555609dc336 in gdb_realpath_keepfile[abi:cxx11](char const*) (filename=0x6060000a8d40 "/home/simark/build/binutils-gdb-one-target/gdb/./x") at /home/simark/src/binutils-gdb/gdbsupport/pathstuff.cc:122
#8 0x000055555ebd2794 in exec_file_attach (filename=0x7fffffffe0f9 "./x", from_tty=1) at /home/simark/src/binutils-gdb/gdb/exec.c:471
#9 0x000055555f2b3fb0 in catch_command_errors (command=0x55555ebd1ab6 <exec_file_attach(char const*, int)>, arg=0x7fffffffe0f9 "./x", from_tty=1, do_bp_actions=false) at /home/simark/src/binutils-gdb/gdb/main.c:513
#10 0x000055555f2b7e11 in captured_main_1 (context=0x7fffffffdb60) at /home/simark/src/binutils-gdb/gdb/main.c:1209
#11 0x000055555f2b9144 in captured_main (data=0x7fffffffdb60) at /home/simark/src/binutils-gdb/gdb/main.c:1319
#12 0x000055555f2b9226 in gdb_main (args=0x7fffffffdb60) at /home/simark/src/binutils-gdb/gdb/main.c:1344
#13 0x000055555d938c5e in main (argc=5, argv=0x7fffffffdcf8) at /home/simark/src/binutils-gdb/gdb/gdb.c:32
The problem is this line in path_join:
gdb_assert (strlen (path) == 0 || !IS_ABSOLUTE_PATH (path));
... where `path` is "x". IS_ABSOLUTE_PATH eventually calls
HAS_DRIVE_SPEC_1:
#define HAS_DRIVE_SPEC_1(dos_based, f) \
((f)[0] && ((f)[1] == ':') && (dos_based))
This macro accesses indices 0 and 1 of the input string. However, `f`
is a string_view of length 1, so it's incorrect to try to access index
1. We know that the string_view's underlying object is a null-terminated
string, so in practice there's no harm. But as far as the string_view
is concerned, index 1 is considered out of bounds.
This patch makes the easy fix, that is to change the path_join parameter
from a vector of to a vector of `const char *`. Another solution would
be to introduce a non-standard gdb::cstring_view class, which would be a
view over a null-terminated string. With that class, it would be
correct to access index 1, it would yield the NUL character. If there
is interest in having this class (it has been mentioned a few times in
the past) I can do it and use it here.
This was found by running tests such as gdb.ada/arrayidx.exp, which
produce 1-char long filenames, so adding a new test is not necessary.
Change-Id: Ia41a16c7243614636b18754fd98a41860756f7af
This fixes build breakage using clang with libc++ on FreeBSD where
std::array<> is not yet declared when used by the path_join variadic
function template.
In this review [1], Eli pointed out that we should be careful when
concatenating file names to avoid duplicated slashes. On Windows, a
double slash at the beginning of a file path has a special meaning. So
naively concatenating "/" and "foo/bar" would give "//foo/bar", which
would not give the desired results. We already have a few spots doing:
if (first_path ends with a slash)
path = first_path + second_path
else
path = first_path + slash + second_path
In general, I think it's nice to avoid superfluous slashes in file
paths, since they might end up visible to the user and look a bit
unprofessional.
Introduce the path_join function that can be used to join multiple path
components together (along with unit tests).
I initially wanted to make it possible to join two absolute paths, to
support the use case of prepending a sysroot path to a target file path,
or the prepending the debug-file-directory to a target file path. But
the code in solib_find_1 shows that it is more complex than this anyway
(for example, when the right hand side is a Windows path with a drive
letter). So I don't think we need to support that case in path_join.
That also keeps the implementation simpler.
Change a few spots to use path_join to show how it can be used. I
believe that all the spots I changed are guarded by some checks that
ensure the right hand side operand is not an absolute path.
Regression-tested on Ubuntu 18.04. Built-tested on Windows, and I also
ran the new unit-test there.
[1] https://sourceware.org/pipermail/gdb-patches/2022-April/187559.html
Change-Id: I0df889f7e3f644e045f42ff429277b732eb6c752
I'm trying to switch these functions to use std::string instead of char
arrays, as much as possible. Some callers benefit from it (can avoid
doing a copy of the result), while others suffer (have to make one more
copy).
Change-Id: I793aab17baaef8345488f4c40b9094e2695425bc
I'm trying to switch these functions to use std::string instead of char
arrays, as much as possible. Some callers benefit from it (can avoid
doing a copy of the result), while others suffer (have to make one more
copy).
Change-Id: Iced49b8ee2f189744c5072a3b217aab5af17a993
I noticed that both gdbserver and gdb define current_directory.
However, as it is referenced by gdbsupport, it seemed better to define
it there as well. This patch also moves the declaration to
pathstuff.h. Tested by rebuilding.
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.
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.
A recent commit caused pathstuff.cc to fail to compile on mingw, like:
../../binutils-gdb/gdbsupport/pathstuff.cc:324:1: error: no previous declaration for 'std::string find_gdb_home_config_file(const char*, _stati64*)' [-Werror=missing-declarations]
Some newly-added #includes were changing which "stat" was being seen
by the compiler. This patch moves the includes to the header, so that
the declaration and definition now agree.
2020-11-10 Tom Tromey <tromey@adacore.com>
PR build/26848:
* pathstuff.h: Move include block here...
* pathstuff.cc: ... from here.
This commit effectively changes the default location of the .gdbinit
file, while maintaining backward compatibility.
For non Apple hosts the .gdbinit file will now be looked for in the
following locations:
$XDG_CONFIG_HOME/gdb/gdbinit
$HOME/.config/gdb/gdbinit
$HOME/.gdbinit
On Apple hosts the search order is instead:
$HOME/Library/Preferences/gdb/gdbinit
$HOME/.gdbinit
I've performed an extensive rewrite of the documentation, moving all
information about initialization files and where to find them into a
new @node, text from other areas has been moved into this one
location, and other areas cross-reference to this new @node as much as
possible.
gdb/ChangeLog:
* NEWS: Mention changes to config file search path.
* main.c
gdb/doc/ChangeLog:
* gdb.texinfo (Mode Options): Descriptions of initialization files
has been moved to 'Initialization Files'.
(Startup): Likewise.
(Initialization Files): New node.
(gdb man): Update to mention alternative file paths.
(gdbinit man): Likewise.
This adds a new get_standard_config_dir, which returns the name of the
configuration directory. In XDG, this is ~/.config/gdb/. Future
patches will make use of this.
2020-07-05 Tom Tromey <tom@tromey.com>
* pathstuff.h (get_standard_config_dir): Declare.
* pathstuff.cc (get_standard_config_dir): New function.
This patch moves the gdbsupport directory to the top level. This is
the next step in the ongoing project to move gdbserver to the top
level.
The bulk of this patch was created by "git mv gdb/gdbsupport gdbsupport".
This patch then adds a build system to gdbsupport and wires it into
the top level. Then it changes gdb to use the top-level build.
gdbserver, on the other hand, is not yet changed. It still does its
own build of gdbsupport.
ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* src-release.sh (GDB_SUPPORT_DIRS): Add gdbsupport.
* MAINTAINERS: Add gdbsupport.
* configure: Rebuild.
* configure.ac (configdirs): Add gdbsupport.
* gdbsupport: New directory, move from gdb/gdbsupport.
* Makefile.def (host_modules, dependencies): Add gnulib.
* Makefile.in: Rebuild.
gdb/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* nat/x86-linux-dregs.c: Include configh.h.
* nat/linux-ptrace.c: Include configh.h.
* nat/linux-btrace.c: Include configh.h.
* defs.h: Include config.h, bfd.h.
* configure.ac: Don't source common.host.
(CONFIG_OBS, CONFIG_SRCS): Remove gdbsupport files.
* configure: Rebuild.
* acinclude.m4: Update path.
* Makefile.in (SUPPORT, LIBSUPPORT, INCSUPPORT): New variables.
(CONFIG_SRC_SUBDIR): Remove gdbsupport.
(INTERNAL_CFLAGS_BASE): Add INCSUPPORT.
(CLIBS): Add LIBSUPPORT.
(CDEPS): Likewise.
(COMMON_SFILES): Remove gdbsupport files.
(HFILES_NO_SRCDIR): Likewise.
(stamp-version): Update path to create-version.sh.
(ALLDEPFILES): Remove gdbsupport files.
gdb/gdbserver/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* server.h: Include config.h.
* gdbreplay.c: Include config.h.
* configure: Rebuild.
* configure.ac: Don't source common.host.
* acinclude.m4: Update path.
* Makefile.in (INCSUPPORT): New variable.
(INCLUDE_CFLAGS): Add INCSUPPORT.
(SFILES): Update paths.
(version-generated.c): Update path to create-version.sh.
(gdbsupport/%-ipa.o, gdbsupport/%.o): Update paths.
gdbsupport/ChangeLog
2020-01-14 Tom Tromey <tom@tromey.com>
* common-defs.h: Add GDBSERVER case. Update includes.
* acinclude.m4, aclocal.m4, config.in, configure, configure.ac,
Makefile.am, Makefile.in, README: New files.
* Moved from ../gdb/gdbsupport/
Change-Id: I07632e7798635c1bab389bf885971e584fb4bb78
