gdb: quote inferior arguments, if needed, when opening a core file

This commit fixes an issue with the commit:

  commit d3d13bf876aae425ae0eff2ab0f1af9f7da0264a
  Date:   Thu Apr 25 09:36:43 2024 +0100

      gdb: add gdbarch method to get execution context from core file

The above commit improves GDB's ability to display inferior arguments
when opening a core file, however, if an argument includes white
space, then this is not displayed as well as it should be.  For
example:

  (gdb) core-file /tmp/corefile-exec-context.2.core
  [New LWP 4069711]
  Reading symbols from /tmp/corefile-exec-context...
  Core was generated by `/tmp/corefile-exec-context aaaaa bbbbb ccccc ddddd e e e e e'.
  Program terminated with signal SIGABRT, Aborted.
  #0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
  50	  return ret;
  (gdb) show args
  Argument list to give program being debugged when it is started is "aaaaa bbbbb ccccc ddddd e\ e\ e\ e\ e".
  (gdb)

Notice the 'Core was generated by ...' line.  In this case it is not
clear if the "e e e e e" is a single argument containing white space,
or 5 single arguments.

But when we 'show args' it is immediately clear that this is a single
argument, as the white space is now escaped.

This problem was caused by the above commit building the argument
string itself, and failing to consider white space escaping.

This commit changes things around, first we place the arguments into
the inferior, then, to print the 'Core was generated by ...' line, we
ask the inferior for the argument string.  In this way the quoting is
handled just as it is for 'show args'.  The initial output is now:

  (gdb) core-file /tmp/corefile-exec-context.2.core
  [New LWP 4069711]
  Reading symbols from /tmp/corefile-exec-context...
  Core was generated by `/tmp/corefile-exec-context aaaaa bbbbb ccccc ddddd e\ e\ e\ e\ e'.
  Program terminated with signal SIGABRT, Aborted.
  #0  0x00007f4f007af625 in raise () from /lib64/libc.so.6
  (gdb)

Much better.  The existing test is extended to cover this case.

Reviewed-By: Guinevere Larsen <guinevere@redhat.com>
Approved-By: Tom Tromey <tom@tromey.com>

2 files changed, 30 insertions, 14 deletions

diff --git a/gdb/corelow.c b/gdb/corelow.c
index 9b9bee0..ee57a9c 100644
--- a/gdb/corelow.c
+++ b/gdb/corelow.c
@@ -1169,27 +1169,22 @@ core_target_open (const char *arg, int from_tty)
 
   if (ctx.valid ())
     {
-      std::string args;
-      for (const auto &a : ctx.args ())
-	{
-	  args += ' ';
-	  args += a.get ();
-	}
-
-      gdb_printf (_("Core was generated by `%ps%s'.\n"),
-		  styled_string (file_name_style.style (),
-				 ctx.execfn ()),
-		  args.c_str ());
-
       /* Copy the arguments into the inferior.  */
       std::vector<char *> argv;
-      for (const auto &a : ctx.args ())
+      for (const gdb::unique_xmalloc_ptr<char> &a : ctx.args ())
 	argv.push_back (a.get ());
       gdb::array_view<char * const> view (argv.data (), argv.size ());
       current_inferior ()->set_args (view);
 
       /* And now copy the environment.  */
       current_inferior ()->environment = ctx.environment ();
+
+      /* Inform the user of executable and arguments.  */
+      const std::string &args = current_inferior ()->args ();
+      gdb_printf (_("Core was generated by `%ps%s%s'.\n"),
+		  styled_string (file_name_style.style (),
+				 ctx.execfn ()),
+		  (args.length () > 0 ? " " : ""), args.c_str ());
     }
   else
     {
diff --git a/gdb/testsuite/gdb.base/corefile-exec-context.exp b/gdb/testsuite/gdb.base/corefile-exec-context.exp
index 73e13e6..d6d4c0d 100644
--- a/gdb/testsuite/gdb.base/corefile-exec-context.exp
+++ b/gdb/testsuite/gdb.base/corefile-exec-context.exp
@@ -69,7 +69,7 @@ gdb_test_multiple "core-file $corefile_1" "load core file no args" {
 }
 
 # Generate a core file, this time pass some arguments to the inferior.
-set args "aaaaa bbbbb ccccc ddddd eeeee"
+set args "aaaaa bbbbb ccccc ddddd e\\\\ e\\\\ e\\\\ e\\\\ e"
 set corefile [core_find $binfile {} $args]
 if {$corefile == ""} {
     untested "unable to create corefile"
@@ -101,6 +101,27 @@ gdb_test_multiple "core-file $corefile_2" "load core file with args" {
 gdb_test "show args" \
     "Argument list to give program being debugged when it is started is \"$args\"\\."
 
+# Move up to 'main'.  Do it this way because we cannot know how many
+# frames up 'main' actually is.
+gdb_test_multiple "up" "move up to main" {
+    -re -wrap "#$decimal\\s+\[^\r\n\]+ in main .*" {
+	pass $gdb_test_name
+    }
+
+    -re -wrap "#$decimal\\s+\[^\r\n\]+ in .*" {
+	send_gdb "up\n"
+	exp_continue
+    }
+}
+
+# Check that the inferior was started with the expected arguments.
+gdb_test "print argc" " = 6"
+gdb_test "print argv\[1\]" " = $hex \"aaaaa\""
+gdb_test "print argv\[2\]" " = $hex \"bbbbb\""
+gdb_test "print argv\[3\]" " = $hex \"ccccc\""
+gdb_test "print argv\[4\]" " = $hex \"ddddd\""
+gdb_test "print argv\[5\]" " = $hex \"e e e e e\""
+
 # Find the name of an environment variable that is not set.
 set env_var_base "GDB_TEST_ENV_VAR_"
 set env_var_name ""