Re: [PATCH v3] gdb, configure: Add disable-formats option for configure

Eli Zaretskii
2025-03-07T12:10:45Z

> From: Guinevere Larsen <guinevere@redhat.com>
> Cc: Guinevere Larsen <guinevere@redhat.com>
> Date: Fri, 7 Mar 2025 08:58:21 -0300
>
> GDB has support for many binary file formats, some which might be very
> unlikely to be found in some situations (such as the COFF format in
> linux). This commit introduces the option for a user to choose which
> formats GDB will support at build configuration time.
>
> This is especially useful to avoid possible security concerns with
> readers that aren't expected to be used at all, as they are one of
> the simplest vectors for an attacker to try and hit GDB with. This
> change can also reduce the size of the final binary, if that is a
> concern.
>
> This commit adds a switch to the configure script allowing a user to
> only enable selected file formats, called --enable-binary-file-formats.
> The default behavior when the switch is omitted is to compile all file
> formats, keeping the original behavior of the script. At the time of
> this commit, the valid options for this option are: dbx, coff (which
> includes coff-pe), xcoff, mips, elf, macho and all. All is treated
> especially, activating all supported readers.
>
> A few targets may require specific binary file format support, as they
> directly call functions defined by the file reader. Specifically,
> windows targets require coff support, and rs6000 aix and lynx178 targets
> require xcoff support. Considering that those formats are the main - or
> only - one available in those targets, I believe it makes sense to
> re-enable those readers. If that happens, the script will emit the
> following warning:
>
> FOO is required to support one or more requested targets. Adding it
>
> Users aren't able to force the disabling of those formats, since GDB
> will not compile without those readers. Ideally we'd like to be able
> to disable even those formats, in case a user wants to build GDB only
> to examine remote files for example, but the current infrastructure
> for the file format readers doesn't allow us to do it.
>
> Mach-O and elf support are also dependent on BFD support being compiled
> in. In case one of those was requested and BFD does not support them,
> the following error is emitted:
>
> FOO was requested, but BFD does not support it.
>
> Finally, this configure switch is also printed by the "show
> configuration" command in GDB.
> ---
> gdb/Makefile.in | 13 +++----
> gdb/NEWS | 11 ++++++
> gdb/README | 24 +++++++++++++
> gdb/config.in | 3 ++
> gdb/configure | 81 +++++++++++++++++++++++++++++++++++++++++---
> gdb/configure.ac | 65 +++++++++++++++++++++++++++++++++--
> gdb/configure.format | 51 ++++++++++++++++++++++++++++
> gdb/configure.tgt | 20 +++++++++--
> gdb/doc/gdb.texinfo | 8 +++++
> gdb/top.c | 5 +++
> 10 files changed, 264 insertions(+), 17 deletions(-)
> create mode 100644 gdb/configure.format

Thanks, but can you describe the changes sine v2, so I could determine
whether I need to review the documentation parts of this? TIA.