[PATCH, doc RFA] New option -D: alias for --data-directory

[Doug Evans <dje@google.com>]

Hi Eli.
Doc RFA please. :-)

2014-04-28  Doug Evans  <dje@google.com>

	New command line option -D.
	* NEWS: Mention it.
	* main.c (set_gdb_data_directory): New function.
	(captured_main): Recognize -D.  Flag error for --data-directory "".
	Call set_gdb_data_directory.
	* main.h (set_gdb_data_directory): Declare.
	* top.c (staged_gdb_datadir): New static global.
	(set_gdb_datadir): Call set_gdb_data_directory
	(show_gdb_datadir): New function.
	(init_main): Update init of data-directory parameter.

	testsuite/
	* gdb.base/catch-syscall.exp (test_catch_syscall_fail_nodatadir):
	Update.
	(do_syscall_tests_without_xml): Update.

	doc/
	* gdb.texinfo (Mode Options): Add -D.

diff --git a/gdb/NEWS b/gdb/NEWS
index d0c44ea..00ec8b9 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -3,6 +3,11 @@
 
 *** Changes since GDB 7.7
 
+* New command line options
+
+-D data-directory
+  This is an alias for the --data-directory option.
+
 * GDB supports printing and modifying of variable length automatic arrays
   as specified in ISO C99.
 
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 9d91075..7795964 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -1164,7 +1164,9 @@ Run @value{GDBN} using @var{directory} as its working directory,
 instead of the current directory.
 
 @item -data-directory @var{directory}
+@itemx -D @var{directory}
 @cindex @code{--data-directory}
+@cindex @code{-D}
 Run @value{GDBN} using @var{directory} as its data directory.
 The data directory is where @value{GDBN} searches for its
 auxiliary files.  @xref{Data Files}.
diff --git a/gdb/main.c b/gdb/main.c
index 59015f5..9652cba 100644
--- a/gdb/main.c
+++ b/gdb/main.c
@@ -106,6 +106,41 @@ get_gdb_program_name (void)
 
 static void print_gdb_help (struct ui_file *);
 
+/* Set the data-directory parameter to NEW_DATADIR.
+   If NEW_DATADIR is not a directory then a warning is printed.
+   We don't signal an error for backward compatibility.  */
+
+void
+set_gdb_data_directory (const char *new_datadir)
+{
+  struct stat st;
+
+  if (stat (new_datadir, &st) < 0)
+    {
+      int save_errno = errno;
+
+      fprintf_unfiltered (gdb_stderr, "Warning: ");
+      print_sys_errmsg (new_datadir, save_errno);
+    }
+  else if (!S_ISDIR (st.st_mode))
+    warning (_("%s is not a directory."), new_datadir);
+
+  xfree (gdb_datadir);
+  gdb_datadir = gdb_realpath (new_datadir);
+
+  /* gdb_realpath won't return an absolute path if the path doesn't exist,
+     but we still want to record an absolute path here.  If the user entered
+     "../foo" and "../foo" doesn't exist then we'll record $(pwd)/../foo which
+     isn't canonical, but that's ok.  */
+  if (!IS_ABSOLUTE_PATH (gdb_datadir))
+    {
+      char *abs_datadir = gdb_abspath (gdb_datadir);
+
+      xfree (gdb_datadir);
+      gdb_datadir = abs_datadir;
+    }
+}
+
 /* Relocate a file or directory.  PROGNAME is the name by which gdb
    was invoked (i.e., argv[0]).  INITIAL is the default value for the
    file or directory.  FLAG is true if the value is relocatable, false
@@ -517,6 +552,7 @@ captured_main (void *data)
       {"directory", required_argument, 0, 'd'},
       {"d", required_argument, 0, 'd'},
       {"data-directory", required_argument, 0, 'D'},
+      {"D", required_argument, 0, 'D'},
       {"cd", required_argument, 0, OPT_CD},
       {"tty", required_argument, 0, 't'},
       {"baud", required_argument, 0, 'b'},
@@ -641,8 +677,15 @@ captured_main (void *data)
 	    gdb_stdout = ui_file_new();
 	    break;
 	  case 'D':
-	    xfree (gdb_datadir);
-	    gdb_datadir = xstrdup (optarg);
+	    if (optarg[0] == '\0')
+	      {
+		fprintf_unfiltered (gdb_stderr,
+				    _("%s: empty path for"
+				      " `--data-directory'\n"),
+				    argv[0]);
+		exit (1);
+	      }
+	    set_gdb_data_directory (optarg);
 	    gdb_datadir_provided = 1;
 	    break;
 #ifdef GDBTK
diff --git a/gdb/main.h b/gdb/main.h
index 089e1c8..502ca30 100644
--- a/gdb/main.h
+++ b/gdb/main.h
@@ -47,4 +47,6 @@ extern char *windows_get_absolute_argv0 (const char *argv0);
    parse the argv array.  */
 extern const char *get_gdb_program_name (void);
 
+extern void set_gdb_data_directory (const char *new_data_dir);
+
 #endif
diff --git a/gdb/testsuite/gdb.base/catch-syscall.exp b/gdb/testsuite/gdb.base/catch-syscall.exp
index da838f7..a70534c 100644
--- a/gdb/testsuite/gdb.base/catch-syscall.exp
+++ b/gdb/testsuite/gdb.base/catch-syscall.exp
@@ -256,7 +256,8 @@ proc test_catch_syscall_fail_nodatadir {} {
 
 	# Make sure GDB doesn't load the syscalls xml from the system
 	# data directory.
-	gdb_test_no_output "set data-directory /the/path/to/nowhere"
+	gdb_test "set data-directory /the/path/to/nowhere" \
+	    "Warning: /the/path/to/nowhere: .*"
 
 	# Testing to see if we receive a warning when calling "catch
 	# syscall" without XML support (without datadir).
@@ -374,7 +375,8 @@ proc test_catch_syscall_with_wrong_args_noxml {} {
 proc do_syscall_tests_without_xml {} {
     # Make sure GDB doesn't load the syscalls xml from the system data
     # directory.
-    gdb_test_no_output "set data-directory /the/path/to/nowhere"
+    gdb_test "set data-directory /the/path/to/nowhere" \
+	"Warning: /the/path/to/nowhere: .*"
 
     # Let's test if we can catch syscalls without XML support.
     # We should succeed, but GDB is not supposed to print syscall names.
diff --git a/gdb/top.c b/gdb/top.c
index fa20025..186b05f 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1668,14 +1668,28 @@ show_exec_done_display_p (struct ui_file *file, int from_tty,
 		    value);
 }
 
+/* New values of the "data-directory" parameter are staged here.  */
+static char *staged_gdb_datadir;
+
 /* "set" command for the gdb_datadir configuration variable.  */
 
 static void
 set_gdb_datadir (char *args, int from_tty, struct cmd_list_element *c)
 {
+  set_gdb_data_directory (staged_gdb_datadir);
   observer_notify_gdb_datadir_changed ();
 }
 
+/* "show" command for the gdb_datadir configuration variable.  */
+
+static void
+show_gdb_datadir (struct ui_file *file, int from_tty,
+		  struct cmd_list_element *c, const char *value)
+{
+  fprintf_filtered (file, _("GDB's data directory is \"%s\".\n"),
+		    gdb_datadir);
+}
+
 static void
 set_history_filename (char *args, int from_tty, struct cmd_list_element *c)
 {
@@ -1793,11 +1807,11 @@ Use \"on\" to enable the notification, and \"off\" to disable it."),
 			   &setlist, &showlist);
 
   add_setshow_filename_cmd ("data-directory", class_maintenance,
-                           &gdb_datadir, _("Set GDB's data directory."),
+                           &staged_gdb_datadir, _("Set GDB's data directory."),
                            _("Show GDB's data directory."),
                            _("\
 When set, GDB uses the specified path to search for data files."),
-                           set_gdb_datadir, NULL,
+                           set_gdb_datadir, show_gdb_datadir,
                            &setlist,
                            &showlist);
 }