Re: [patch 1/2] Provide $ddir substitution for --with-auto-load-safe-path

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

On Wed, 09 May 2012 19:41:08 +0200, Eli Zaretskii wrote:
> Okay with that.  Thanks.

Updated just the doc.


Thanks,
Jan



gdb/
2012-05-09  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Provide $ddir substitution for --with-auto-load-safe-path.
	* NEWS (--with-auto-load-safe-path, --without-auto-load-safe-path): New
	entries.
	* auto-load.c: Include observer.h.
	(auto_load_safe_path_vec_update): Call substitute_path_component for
	each component.  New variable ddir_subst.
	(auto_load_gdb_datadir_changed): New function.
	(set_auto_load_safe_path): Rename DEFAULT_AUTO_LOAD_SAFE_PATH to
	AUTO_LOAD_SAFE_PATH.  New comment.
	(_initialize_auto_load): Rename DEFAULT_AUTO_LOAD_SAFE_PATH to
	AUTO_LOAD_SAFE_PATH.  Install auto_load_gdb_datadir_changed.
	* config.in: Regenerate.
	* configure: Regenerate.
	* configure.ac (--auto-load-safe-path): Rename
	DEFAULT_AUTO_LOAD_SAFE_PATH to AUTO_LOAD_SAFE_PATH.  Default to
	GDB_DATADIR/auto-load.
	* defs.h (substitute_path_component): New declaration.
	* top.c: Include observer.h.
	(set_gdb_datadir): New function.
	(init_main): Install it for "set data-directory".
	* utils.c (substitute_path_component): New function.

gdb/doc/
2012-05-09  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Provide $ddir substitution for --with-auto-load-safe-path.
	* gdb.texinfo (Auto-loading): Replace /usr/local by $ddir/auto-load.
	(Auto-loading safe path): Likewise.  Mention the default value,
	$ddir substitution, --with-auto-load-safe-path and
	--without-auto-load-safe-path.
	* observer.texi (gdb_datadir_changed): New.

--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -181,6 +181,17 @@ set debug auto-load on|off
 show debug auto-load
   Control display of debugging info for auto-loading the files above.
 
+* New configure options
+
+--with-auto-load-safe-path
+  Configure default value for the 'set auto-load safe-path' setting
+  above.  It defaults to '$ddir/auto-load', $ddir representing the value
+  of configure option --with-gdb-datadir.
+
+--without-auto-load-safe-path
+  Set 'set auto-load safe-path' to '/', effectively disabling this
+  security feature.
+
 * New remote packets
 
 z0/z1 conditional breakpoints extension
--- a/gdb/auto-load.c
+++ b/gdb/auto-load.c
@@ -35,6 +35,7 @@
 #include "gdb_vecs.h"
 #include "readline/tilde.h"
 #include "completer.h"
+#include "observer.h"
 
 /* The suffix of per-objfile scripts to auto-load as non-Python command files.
    E.g. When the program loads libfoo.so, look for libfoo-gdb.gdb.  */
@@ -141,10 +142,16 @@ auto_load_safe_path_vec_update (void)
   for (ix = 0; ix < len; ix++)
     {
       char *dir = VEC_index (char_ptr, auto_load_safe_path_vec, ix);
-      char *expanded = tilde_expand (dir);
-      char *real_path = gdb_realpath (expanded);
+      char *ddir_subst, *expanded, *real_path;
+
+      ddir_subst = xstrdup (dir);
+      substitute_path_component (&ddir_subst, "$ddir", gdb_datadir);
+      expanded = tilde_expand (ddir_subst);
+      xfree (ddir_subst);
+      real_path = gdb_realpath (expanded);
 
-      /* Ensure the current entry is at least tilde_expand-ed.  */
+      /* Ensure the current entry is at least a valid path (therefore
+	 $ddir-expanded and tilde-expanded).  */
       VEC_replace (char_ptr, auto_load_safe_path_vec, ix, expanded);
 
       if (debug_auto_load)
@@ -176,15 +183,24 @@ auto_load_safe_path_vec_update (void)
     }
 }
 
+/* Variable gdb_datadir has been set.  Update content depending on $ddir.  */
+
+static void
+auto_load_gdb_datadir_changed (void)
+{
+  auto_load_safe_path_vec_update ();
+}
+
 /* "set" command for the auto_load_safe_path configuration variable.  */
 
 static void
 set_auto_load_safe_path (char *args, int from_tty, struct cmd_list_element *c)
 {
+  /* Setting the variable to "" resets it to the compile time defaults.  */
   if (auto_load_safe_path[0] == '\0')
     {
       xfree (auto_load_safe_path);
-      auto_load_safe_path = xstrdup (DEFAULT_AUTO_LOAD_SAFE_PATH);
+      auto_load_safe_path = xstrdup (AUTO_LOAD_SAFE_PATH);
     }
 
   auto_load_safe_path_vec_update ();
@@ -1040,7 +1056,7 @@ This options has security implications for untrusted inferiors."),
 Usage: info auto-load local-gdbinit"),
 	   auto_load_info_cmdlist_get ());
 
-  auto_load_safe_path = xstrdup (DEFAULT_AUTO_LOAD_SAFE_PATH);
+  auto_load_safe_path = xstrdup (AUTO_LOAD_SAFE_PATH);
   auto_load_safe_path_vec_update ();
   add_setshow_optional_filename_cmd ("safe-path", class_support,
 				     &auto_load_safe_path, _("\
@@ -1058,6 +1074,7 @@ This options has security implications for untrusted inferiors."),
 				     show_auto_load_safe_path,
 				     auto_load_set_cmdlist_get (),
 				     auto_load_show_cmdlist_get ());
+  observer_attach_gdb_datadir_changed (auto_load_gdb_datadir_changed);
 
   cmd = add_cmd ("add-auto-load-safe-path", class_support,
 		 add_auto_load_safe_path,
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -3,6 +3,9 @@
 /* Define if building universal (internal helper macro) */
 #undef AC_APPLE_UNIVERSAL_BUILD
 
+/* Directories safe to hold auto-loaded files. */
+#undef AUTO_LOAD_SAFE_PATH
+
 /* Directory of programs. */
 #undef BINDIR
 
@@ -24,9 +27,6 @@
    moved. */
 #undef DEBUGDIR_RELOCATABLE
 
-/* Directories safe to hold auto-loaded files. */
-#undef DEFAULT_AUTO_LOAD_SAFE_PATH
-
 /* Define to BFD's default architecture. */
 #undef DEFAULT_BFD_ARCH
 
--- a/gdb/configure
+++ b/gdb/configure
@@ -1486,7 +1486,8 @@ Optional Packages:
   --with-relocated-sources=PATH
                           automatically relocate this path for source files
   --with-auto-load-safe-path=PATH
-                          directories safe to hold auto-loaded files
+                          directories safe to hold auto-loaded files, use
+                          $ddir for --with-gdb-datadir path [$ddir/auto-load]
   --without-auto-load-safe-path
                           do not restrict auto-loaded files locations
   --with-libunwind-ia64   use libunwind frame unwinding for ia64 targets
@@ -4964,20 +4965,21 @@ $as_echo_n "checking for default auto-load safe-path... " >&6; }
 # Check whether --with-auto-load-safe-path was given.
 if test "${with_auto_load_safe_path+set}" = set; then :
   withval=$with_auto_load_safe_path; if test "$with_auto_load_safe_path" = "no"; then
-   with_auto_load_safe_path="/"
- fi
+     with_auto_load_safe_path="/"
+     fi
 else
-  with_auto_load_safe_path="$prefix"
+  with_auto_load_safe_path='$ddir/auto-load'
 fi
 
+escape_dir=`echo $with_auto_load_safe_path | sed 's/[$]ddir\>/\\\\\\\\\\\\&/g'`
 
   test "x$prefix" = xNONE && prefix="$ac_default_prefix"
   test "x$exec_prefix" = xNONE && exec_prefix='${prefix}'
-  ac_define_dir=`eval echo $with_auto_load_safe_path`
+  ac_define_dir=`eval echo $escape_dir`
   ac_define_dir=`eval echo $ac_define_dir`
 
 cat >>confdefs.h <<_ACEOF
-#define DEFAULT_AUTO_LOAD_SAFE_PATH "$ac_define_dir"
+#define AUTO_LOAD_SAFE_PATH "$ac_define_dir"
 _ACEOF
 
 
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -138,13 +138,16 @@ AS_HELP_STRING([--with-relocated-sources=PATH], [automatically relocate this pat
 
 AC_MSG_CHECKING([for default auto-load safe-path])
 AC_ARG_WITH(auto-load-safe-path,
-AS_HELP_STRING([--with-auto-load-safe-path=PATH], [directories safe to hold auto-loaded files])
-AS_HELP_STRING([--without-auto-load-safe-path], [do not restrict auto-loaded files locations]),
-[if test "$with_auto_load_safe_path" = "no"; then
-   with_auto_load_safe_path="/"
- fi],
-[with_auto_load_safe_path="$prefix"])
-AC_DEFINE_DIR(DEFAULT_AUTO_LOAD_SAFE_PATH, with_auto_load_safe_path,
+AS_HELP_STRING([--with-auto-load-safe-path=PATH],
+  [directories safe to hold auto-loaded files, use $ddir for --with-gdb-datadir path @<:@$ddir/auto-load@:>@])
+AS_HELP_STRING([--without-auto-load-safe-path],
+               [do not restrict auto-loaded files locations]),
+    [if test "$with_auto_load_safe_path" = "no"; then
+     with_auto_load_safe_path="/"
+     fi],
+[with_auto_load_safe_path='$ddir/auto-load'])
+escape_dir=`echo $with_auto_load_safe_path | sed 's/[[$]]ddir\>/\\\\\\\\\\\\&/g'`
+AC_DEFINE_DIR(AUTO_LOAD_SAFE_PATH, escape_dir,
 	      [Directories safe to hold auto-loaded files.])
 AC_MSG_RESULT([$with_auto_load_safe_path])
 
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -381,6 +381,9 @@ extern struct cleanup *make_bpstat_clear_actions_cleanup (void);
 
 extern int producer_is_gcc_ge_4 (const char *producer);
 
+extern void substitute_path_component (char **stringp, const char *from,
+				       const char *to);
+
 #ifdef HAVE_WAITPID
 extern pid_t wait_to_die_with_timeout (pid_t pid, int *status, int timeout);
 #endif
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -21007,7 +21007,7 @@ libthread-db:  Auto-loading of inferior specific libthread_db is on.
 local-gdbinit:  Auto-loading of .gdbinit script from current directory is on.
 python-scripts:  Auto-loading of Python scripts is on.
 safe-path:  List of directories from which it is safe to auto-load files
-            is /usr/local.
+            is $ddir/auto-load.
 @end smallexample
 
 @anchor{info auto-load}
@@ -21209,9 +21209,9 @@ get loaded:
 $ ./gdb -q ./gdb
 Reading symbols from /home/user/gdb/gdb...done.
 warning: File "/home/user/gdb/gdb-gdb.gdb" auto-loading has been
-         declined by your `auto-load safe-path' set to "/usr/local".
+         declined by your `auto-load safe-path' set to "$ddir/auto-load".
 warning: File "/home/user/gdb/gdb-gdb.py" auto-loading has been
-         declined by your `auto-load safe-path' set to "/usr/local".
+         declined by your `auto-load safe-path' set to "$ddir/auto-load".
 @end smallexample
 
 The list of trusted directories is controlled by the following commands:
@@ -21243,7 +21243,18 @@ loading and execution of scripts.  Multiple entries may be delimited by the
 host platform directory separator in use.
 @end table
 
-Setting this variable to @file{/} disables this security protection.
+This variable defaults to @file{$ddir/auto-load}.  The default @code{set
+auto-load safe-path} value can be also overriden by @value{GDBN} configuration
+option @option{--with-auto-load-safe-path}.
+
+Any used string @file{$ddir} will get replaced by @var{data-directory} which is
+determined at @value{GDBN} startup (@pxref{Data Files}).  @file{$ddir} must be
+be placed as a directory component --- either alone or delimited by @file{/} or
+@file{\} directory separators, depending on the host platform.
+
+Setting this variable to @file{/} disables this security protection,
+corresponding @value{GDBN} configuration option is
+@option{--without-auto-load-safe-path}.
 This variable is supposed to be set to the system directories writable by the
 system superuser only.  Users can add their source directories in init files in
 their home directories (@pxref{Home Directory Init File}).  See also deprecated
--- a/gdb/doc/observer.texi
+++ b/gdb/doc/observer.texi
@@ -226,6 +226,10 @@ Called before a top-level prompt is displayed.  @var{current_prompt} is
 the current top-level prompt.
 @end deftypefun
 
+@deftypefun void gdb_datadir_changed (void)
+Variable gdb_datadir has been set.  The value may not necessarily change.
+@end deftypefun
+
 @deftypefun void test_notification (int @var{somearg})
 This observer is used for internal testing.  Do not use.  
 See testsuite/gdb.gdb/observer.exp.
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -47,6 +47,7 @@
 #include "gdbthread.h"
 #include "python/python.h"
 #include "interps.h"
+#include "observer.h"
 
 /* readline include files.  */
 #include "readline/readline.h"
@@ -1559,6 +1560,15 @@ show_exec_done_display_p (struct ui_file *file, int from_tty,
 			    "asynchronous execution commands is %s.\n"),
 		    value);
 }
+
+/* "set" command for the gdb_datadir configuration variable.  */
+
+static void
+set_gdb_datadir (char *args, int from_tty, struct cmd_list_element *c)
+{
+  observer_notify_gdb_datadir_changed ();
+}
+
 static void
 init_main (void)
 {
@@ -1666,7 +1676,7 @@ Use \"on\" to enable the notification, and \"off\" to disable it."),
                            _("Show GDB's data directory."),
                            _("\
 When set, GDB uses the specified path to search for data files."),
-                           NULL, NULL,
+                           set_gdb_datadir, NULL,
                            &setlist,
                            &showlist);
 }
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -3724,6 +3724,48 @@ dirnames_to_char_ptr_vec (const char *dirnames)
   return retval;
 }
 
+/* Substitute all occurences of string FROM by string TO in *STRINGP.  *STRINGP
+   must come from xrealloc-compatible allocator and it may be updated.  FROM
+   needs to be delimited by IS_DIR_SEPARATOR (or be located at the start or
+   end of *STRINGP.  */
+
+void
+substitute_path_component (char **stringp, const char *from, const char *to)
+{
+  char *string = *stringp, *s;
+  const size_t from_len = strlen (from);
+  const size_t to_len = strlen (to);
+
+  for (s = string;;)
+    {
+      s = strstr (s, from);
+      if (s == NULL)
+	break;
+
+      if ((s == string || IS_DIR_SEPARATOR (s[-1]))
+          && (s[from_len] == '\0' || IS_DIR_SEPARATOR (s[from_len])))
+	{
+	  char *string_new;
+
+	  string_new = xrealloc (string, (strlen (string) + to_len + 1));
+
+	  /* Relocate the current S pointer.  */
+	  s = s - string + string_new;
+	  string = string_new;
+
+	  /* Replace from by to.  */
+	  memmove (&s[to_len], &s[from_len], strlen (&s[from_len]) + 1);
+	  memcpy (s, to, to_len);
+
+	  s += to_len;
+	}
+      else
+	s++;
+    }
+
+  *stringp = string;
+}
+
 #ifdef HAVE_WAITPID
 
 #ifdef SIGALRM