gdb: move remote arg splitting and joining into gdbsupport/

This is a refactoring commit.  When passing inferior arguments to
gdbserver we have two actions that need to be performed, splitting and
joining.

On the GDB side, we take the inferior arguments, a single string, and
split the string into a list of individual arguments.  These are then
sent to gdbserver over the remote protocol.

On the gdbserver side we receive the list of individual arguments and
join these back together into a single inferior argument string.

In the next commit I plan to add some unit testing for this remote
argument passing process.  Ideally, for unit testing, we need the code
being tested to be located in some easily callable function, rather
than being inline at the site of use.

So in this commit I propose to move the splitting and joining logic
out into a separate file, we can then use this within GDB and
gdbserver when passing arguments between GDB and gdbserver, but we can
also call the same functions for some unit testing.

In this commit I'm not adding the unit tests, they will be added next,
so for now there should be no user visible changes after this commit.

Tested-By: Guinevere Larsen <guinevere@redhat.com>

diff --git a/gdb/remote.c b/gdb/remote.c
index 75cc21c505b4c52d01cd2fb54c1f60d5eaaf6509..73dc426b2e87dbd08d3f0dcfda7369ebfe321afd 100644 (file)
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -80,6 +80,7 @@
 #include "async-event.h"
 #include "gdbsupport/selftest.h"
 #include "cli/cli-style.h"
+#include "gdbsupport/remote-args.h"
 
 /* The remote target.  */
 
@@ -10835,16 +10836,15 @@ remote_target::extended_remote_run (const std::string &args)
 
   if (!args.empty ())
     {
-      int i;
+      std::vector<std::string> split_args = gdb::remote_args::split (args);
 
-      gdb_argv argv (args.c_str ());
-      for (i = 0; argv[i] != NULL; i++)
+      for (const auto &a : split_args)
        {
-         if (strlen (argv[i]) * 2 + 1 + len >= get_remote_packet_size ())
+         if (a.size () * 2 + 1 + len >= get_remote_packet_size ())
            error (_("Argument list too long for run packet"));
          rs->buf[len++] = ';';
-         len += 2 * bin2hex ((gdb_byte *) argv[i], rs->buf.data () + len,
-                             strlen (argv[i]));
+         len += 2 * bin2hex ((gdb_byte *) a.c_str (), rs->buf.data () + len,
+                             a.size ());
        }
     }
 

diff --git a/gdbserver/server.cc b/gdbserver/server.cc
index 0ce40ee50d1579a7cdcf73c2b0992f9ff9f15db3..4b1f4b2afbc27440e460811f07a250dc299f7af8 100644 (file)
--- a/gdbserver/server.cc
+++ b/gdbserver/server.cc
@@ -51,6 +51,7 @@
 #include "gdbsupport/scoped_restore.h"
 #include "gdbsupport/search.h"
 #include "gdbsupport/gdb_argv_vec.h"
+#include "gdbsupport/remote-args.h"
 
 /* PBUFSIZ must also be at least as big as IPA_CMD_BUF_SIZE, because
    the client state data is passed directly to some agent
@@ -3465,7 +3466,7 @@ handle_v_run (char *own_buf)
   else
     program_path.set (new_program_name.get ());
 
-  program_args = construct_inferior_arguments (new_argv.get (), true);
+  program_args = gdb::remote_args::join (new_argv.get ());
 
   try
     {

diff --git a/gdbsupport/Makefile.am b/gdbsupport/Makefile.am
index 79aef9522b1509095c704f3e94c16689b6dc12ad..20122e42cd5ad5414d5f9363ffdbdbd5da53f61e 100644 (file)
--- a/gdbsupport/Makefile.am
+++ b/gdbsupport/Makefile.am
@@ -80,6 +80,7 @@ libgdbsupport_a_SOURCES = \
     pathstuff.cc \
     print-utils.cc \
     ptid.cc \
+    remote-args.cc \
     rsp-low.cc \
     run-time-clock.cc \
     safe-strerror.cc \

diff --git a/gdbsupport/Makefile.in b/gdbsupport/Makefile.in
index c2feacc9de112877d57b4539089afeed8f8a08f1..66b8891a6b4d65db104ca3eea3baa5fbf70fc74f 100644 (file)
--- a/gdbsupport/Makefile.in
+++ b/gdbsupport/Makefile.in
@@ -163,12 +163,12 @@ am_libgdbsupport_a_OBJECTS = agent.$(OBJEXT) btrace-common.$(OBJEXT) \
        gdb_tilde_expand.$(OBJEXT) gdb_wait.$(OBJEXT) \
        gdb_vecs.$(OBJEXT) job-control.$(OBJEXT) netstuff.$(OBJEXT) \
        new-op.$(OBJEXT) osabi.$(OBJEXT) pathstuff.$(OBJEXT) \
-       print-utils.$(OBJEXT) ptid.$(OBJEXT) rsp-low.$(OBJEXT) \
-       run-time-clock.$(OBJEXT) safe-strerror.$(OBJEXT) \
-       scoped_mmap.$(OBJEXT) search.$(OBJEXT) signals.$(OBJEXT) \
-       signals-state-save-restore.$(OBJEXT) task-group.$(OBJEXT) \
-       tdesc.$(OBJEXT) thread-pool.$(OBJEXT) xml-utils.$(OBJEXT) \
-       $(am__objects_1) $(am__objects_2)
+       print-utils.$(OBJEXT) ptid.$(OBJEXT) remote-args.$(OBJEXT) \
+       rsp-low.$(OBJEXT) run-time-clock.$(OBJEXT) \
+       safe-strerror.$(OBJEXT) scoped_mmap.$(OBJEXT) search.$(OBJEXT) \
+       signals.$(OBJEXT) signals-state-save-restore.$(OBJEXT) \
+       task-group.$(OBJEXT) tdesc.$(OBJEXT) thread-pool.$(OBJEXT) \
+       xml-utils.$(OBJEXT) $(am__objects_1) $(am__objects_2)
 libgdbsupport_a_OBJECTS = $(am_libgdbsupport_a_OBJECTS)
 AM_V_P = $(am__v_P_@AM_V@)
 am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
@@ -438,6 +438,7 @@ libgdbsupport_a_SOURCES = \
     pathstuff.cc \
     print-utils.cc \
     ptid.cc \
+    remote-args.cc \
     rsp-low.cc \
     run-time-clock.cc \
     safe-strerror.cc \
@@ -548,6 +549,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/pathstuff.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/print-utils.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ptid.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/remote-args.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/rsp-low.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/run-time-clock.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/safe-strerror.Po@am__quote@

diff --git a/gdbsupport/remote-args.cc b/gdbsupport/remote-args.cc
new file mode 100644 (file)
index 0000000..2493433
--- /dev/null
+++ b/gdbsupport/remote-args.cc
@@ -0,0 +1,43 @@
+/* Copyright (C) 2023-2025 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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 <http://www.gnu.org/licenses/>.  */
+
+#include "gdbsupport/common-defs.h"
+#include "gdbsupport/remote-args.h"
+#include "gdbsupport/common-inferior.h"
+#include "gdbsupport/buildargv.h"
+
+/* See remote-args.h.  */
+
+std::vector<std::string>
+gdb::remote_args::split (const std::string &args)
+{
+  std::vector<std::string> results;
+
+  gdb_argv argv (args.c_str ());
+  for (int i = 0; argv[i] != nullptr; i++)
+    results.emplace_back (argv[i]);
+
+  return results;
+}
+
+/* See remote-args.h.  */
+
+std::string
+gdb::remote_args::join (const std::vector<char *> &args)
+{
+  return construct_inferior_arguments (args, true);
+}

diff --git a/gdbsupport/remote-args.h b/gdbsupport/remote-args.h
new file mode 100644 (file)
index 0000000..93dbdc6
--- /dev/null
+++ b/gdbsupport/remote-args.h
@@ -0,0 +1,55 @@
+/* Functions to help when passing arguments between GDB and gdbserver.
+
+   Copyright (C) 2023-2025 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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 <http://www.gnu.org/licenses/>.  */
+
+/* The functions declared here are used when passing inferior arguments
+   from GDB to gdbserver.
+
+   The remote protocol requires that arguments are passed as a vector of
+   separate argument while GDB stores the arguments as a single string, and
+   gdbserver also requires the arguments be a single string.
+
+   These functions then provide a mechanism to split up an argument string
+   and recombine it within gdbserver while preserving escaping of special
+   characters within the argument string.  */
+
+namespace gdb
+{
+
+namespace remote_args
+{
+
+/* ARGS is an inferior argument string.  This function splits ARGS into
+   individual arguments and returns a vector containing each argument.  */
+
+extern std::vector<std::string> split (const std::string &args);
+
+/* Join together the separate arguments in ARGS and build a single
+   inferior argument string.  The string returned by this function will be
+   equivalent, but not necessarily identical to the string passed to
+   ::split, for example passing the string '"a b"' (without the single
+   quotes, but including the double quotes) to ::split, will return an
+   argument of 'a b' (without the single quotes).  When this argument is
+   passed through ::join we will get back the string 'a\ b' (without the
+   single quotes), that is, we choose to escape the white space, rather
+   than wrap the argument in quotes.  */
+extern std::string join (const std::vector<char *> &args);
+
+} /* namespace remote_args */
+
+} /* namespac gdb */