From: Andrew Burgess Date: Sun, 7 Jan 2024 13:46:29 +0000 (+0000) Subject: gdb: new maintenance command to help debug remote argument issues X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=84dd63f3279dc0d1e13351dbc7b11261800e4758;p=thirdparty%2Fbinutils-gdb.git gdb: new maintenance command to help debug remote argument issues Add a new maintenance command 'maint test-remote-args', this command takes an argument string and splits it using gdb::remote_args::split and then joins the result using gdb::remote_args::join and prints all of the results. This is useful for diagnosing problems with remote argument passing. This new command is identical to what the remote argument self-tests do, but while I was working on improving remote argument passing it was far easier to have a command that I could just throw example strings at, rather than having to add new selftests and recompile GDB. I ended up adding a couple of additional helper functions to the gdb::argv_vec class. Reviewed-By: Eli Zaretskii Tested-By: Guinevere Larsen Approved-By: Kevin Buettner --- diff --git a/gdb/NEWS b/gdb/NEWS index 87c72cb3d9f..8be367d2424 100644 --- a/gdb/NEWS +++ b/gdb/NEWS @@ -18,6 +18,12 @@ GNU/Linux/MicroBlaze (gdbserver) microblazeel-*linux* +* New commands + +maintenance test-remote-args ARGS + Test splitting and joining of inferior arguments ARGS as they would + be split and joined when being passed to a remote target. + * Changed remote packets single-inf-arg in qSupported diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 462b86c87e6..e8515883820 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -42842,6 +42842,26 @@ These are representative commands for each @var{kind} of setting type @value{GDBN} supports. They are used by the testsuite for exercising the settings infrastructure. +@kindex maint test-remote-args +@item maint test-remote-args @var{args} +For targets that don't support passing inferior arguments as a single +string (@pxref{single-inf-arg}), @value{GDBN} will attempt to split +the inferior arguments before passing them to the remote target, and +the remote target might choose to join the inferior arguments upon +receipt. Historically gdbserver did join inferior arguments, but now +it will request inferior arguments be passed as a single string if +@value{GDBN} supports this feature. + +This maintenance command splits @var{args} as @value{GDBN} would +normally split such an argument string before passing the arguments to +a remote target, the split arguments are then printed. + +The split arguments are then joined together as gdbserver would join +them, and the result is printed. + +This command is intended to help diagnose issues passing inferior +arguments to remote targets. + @kindex maint set backtrace-on-fatal-signal @kindex maint show backtrace-on-fatal-signal @item maint set backtrace-on-fatal-signal [on|off] diff --git a/gdb/remote.c b/gdb/remote.c index e1b54c6f9af..9fc8712f699 100644 --- a/gdb/remote.c +++ b/gdb/remote.c @@ -81,6 +81,7 @@ #include "gdbsupport/selftest.h" #include "cli/cli-style.h" #include "gdbsupport/remote-args.h" +#include "gdbsupport/gdb_argv_vec.h" /* The remote target. */ @@ -12278,6 +12279,51 @@ cli_packet_command (const char *args, int from_tty) send_remote_packet (view, &cb); } +/* Implement 'maint test-remote-args' command. + + Treat ARGS as an argument string. Split the remote arguments using + gdb::remote_args::split, and then join using gdb::remote_args::join. + The split and joined arguments are printed out. Additionally, the + joined arguments are split and joined a second time, and compared to the + result of the first join, this provides some basic validation that GDB + sess the joined arguments as equivalent to the original argument + string. */ + +static void +test_remote_args_command (const char *args, int from_tty) +{ + std::vector split_args = gdb::remote_args::split (args); + + gdb_printf ("Input (%s)\n", args); + for (const std::string &a : split_args) + gdb_printf (" (%s)\n", a.c_str ()); + + gdb::argv_vec tmp_split_args; + for (const std::string &a : split_args) + tmp_split_args.emplace_back (xstrdup (a.c_str ())); + + std::string joined_args = gdb::remote_args::join (tmp_split_args.get ()); + + gdb_printf ("Output (%s)\n", joined_args.c_str ()); + + std::vector resplit = gdb::remote_args::split (joined_args); + + tmp_split_args.clear (); + for (const std::string &a : resplit) + tmp_split_args.emplace_back (xstrdup (a.c_str ())); + + std::string rejoined = gdb::remote_args::join (tmp_split_args.get ()); + + if (joined_args != rejoined || split_args != resplit) + { + gdb_printf ("FAILURE ON REJOINING\n"); + gdb_printf ("Resplit args:\n"); + for (const auto & a : resplit) + gdb_printf (" (%s)\n", a.c_str ()); + gdb_printf ("Rejoined (%s)\n", rejoined.c_str ()); + } +} + #if 0 /* --------- UNIT_TEST for THREAD oriented PACKETS ------------------- */ @@ -16726,6 +16772,20 @@ from the target."), /* Eventually initialize fileio. See fileio.c */ initialize_remote_fileio (&remote_set_cmdlist, &remote_show_cmdlist); + add_cmd ("test-remote-args", class_maintenance, + test_remote_args_command, _("\ +Test remote argument splitting and joining.\n \ + maintenance test-remote-args ARGS\n\ +For remote targets that don't support passing inferior arguments as a\n\ +single string, GDB needs to split the inferior arguments before passing\n\ +them, and gdbserver needs to join the arguments it receives.\n\ +This command splits ARGS just as GDB would before passing them to a\n\ +remote target, and prints the result. This command then joins the\n\ +arguments just as gdbserver would, and prints the results.\n\ +This command is useful in diagnosing problems when passing arguments\n\ +between GDB and a remote target."), + &maintenancelist); + #if GDB_SELF_TEST selftests::register_test ("remote_memory_tagging", selftests::test_memory_tagging_functions); diff --git a/gdb/testsuite/gdb.base/maint-test-remote-args.exp b/gdb/testsuite/gdb.base/maint-test-remote-args.exp new file mode 100644 index 00000000000..6cd3006f4c8 --- /dev/null +++ b/gdb/testsuite/gdb.base/maint-test-remote-args.exp @@ -0,0 +1,40 @@ +# Copyright 2024-2025 Free Software Foundation, Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +# Test the 'maint test-remote-args' command. +# +# We do minimal testing in here. If you are thinking of adding a new +# test here then you are most likely adding the test in the wrong +# place. Remote argument testing is checked in the following test +# scripts: gdb.base/args.exp, gdb.base/inferior-args.exp, +# gdb.base/startup-with-shell.exp, and gdb.python/py-inferior.exp. +# The test gdb.gdb/unittest.exp also runs 'maint selftest +# remote-args', which are the remote argument self tests. +# +# If you have a new test for an argument that was being passed +# incorrectly, then add the test to one of those scripts. +# +# This file is ONLY for validating that the 'maint test-remote-args' +# command itself is working. + +gdb_start + +gdb_test "maint test-remote-args a b c" \ + [multi_line \ + "Input \\(a b c\\)" \ + " \\(a\\)" \ + " \\(b\\)" \ + " \\(c\\)" \ + "Output \\(a b c\\)"] diff --git a/gdbsupport/gdb_argv_vec.h b/gdbsupport/gdb_argv_vec.h index 1f3b6dbb40e..43571ae173a 100644 --- a/gdbsupport/gdb_argv_vec.h +++ b/gdbsupport/gdb_argv_vec.h @@ -90,6 +90,15 @@ public: m_args.push_back (value); } + /* Like calling emplace_back on the underlying vector. This class takes + ownership of the value added to the vector, and will release the value + by calling xfree() on it when this object is destroyed. */ + template + reference emplace_back (Args &&...args) + { + return m_args.emplace_back (std::forward (args)...); + } + /* Non constant iterator to start of m_args. */ iterator begin () { @@ -133,6 +142,12 @@ public: { return m_args.empty (); } + + /* Clear the argument vector. */ + void clear () + { + free_vector_argv (m_args); + } }; } /* namespac gdb */