[PATCH 3/3 v3] Load system gdbinit files from a directory

["Christian Biesinger via gdb-patches" <gdb-patches@sourceware.org>]

[Looks like I never did send this updated patch :( Please take another
look!]

Adds a configure option --with-system-gdbinit-dir to specify a directory
in which to look for gdbinit files.  All files in this directory are
loaded on startup (subject to -n/-nx as usual) as long as the extension
matches a known and enabled scripting language (.gdb/.py/.scm).

This also changes get_ext_lang_of_file to support ".gdb" files, similar
to get_ext_lang_defn's handling of EXT_LANG_GDB.

gdb/ChangeLog:

2019-08-20  Christian Biesinger  <cbiesinger@google.com>

	* NEWS: Mention new --with-system-gdbinit-dir option.
	* config.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Add new option --with-system-gdbinit-dir.
	* extension.c (get_ext_lang_of_file): Return extension_language_gdb
	for a ".gdb" suffix.
	* main.c (get_init_files): Change system_gdbinit argument to
	a vector and return the files in SYSTEM_GDBINIT_DIR in
	addition to SYSTEM_GDBINIT.
	(captured_main_1): Update.
	(print_gdb_help): Update.
	* top.c (print_gdb_configuration): Also print the value of
	SYSTEM_GDBINIT_DIR.

gdb/doc/ChangeLog:

2019-08-25  Christian Biesinger  <cbiesinger@google.com>

	* gdb.texinfo (many sections): Document new --with-system-gdbinit-dir
	option.
---
 gdb/NEWS            |  6 ++++
 gdb/config.in       |  7 ++++
 gdb/configure       | 51 +++++++++++++++++++++++++++++
 gdb/configure.ac    |  3 ++
 gdb/doc/gdb.texinfo | 67 ++++++++++++++++++++++++++++++++-----
 gdb/extension.c     |  3 ++
 gdb/main.c          | 80 +++++++++++++++++++++++++++++++++++++--------
 gdb/top.c           |  4 +++
 8 files changed, 199 insertions(+), 22 deletions(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index 779fd91d3a..1d0f56a119 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -34,6 +34,12 @@
 
 * GDB can now be compiled with Python 3 on Windows.
 
+* In addition to the system-wide gdbinit file, if configured with
+ --with-system-gdbinit-dir, GDB will now also load files in that directory
+ as system gdbinit files, unless the -nx or -n flag is provided.  Files
+ with extensions .gdb, .py and .scm are supported as long as GDB was
+ compiled with support for that language.
+
 * Python API
 
   ** The gdb.Value type has a new method 'format_string' which returns a
diff --git a/gdb/config.in b/gdb/config.in
index 26ca02f6a3..c0745c90a3 100644
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -684,6 +684,13 @@
 /* automatically load a system-wide gdbinit file */
 #undef SYSTEM_GDBINIT
 
+/* automatically load system-wide gdbinit files from this directory */
+#undef SYSTEM_GDBINIT_DIR
+
+/* Define if the system-gdbinit-dir directory should be relocated when GDB is
+   moved. */
+#undef SYSTEM_GDBINIT_DIR_RELOCATABLE
+
 /* Define if the system-gdbinit directory should be relocated when GDB is
    moved. */
 #undef SYSTEM_GDBINIT_RELOCATABLE
diff --git a/gdb/configure b/gdb/configure
index 22a5f6051d..8436f06c9f 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -693,6 +693,7 @@ WIN32LIBS
 SER_HARDWIRE
 WERROR_CFLAGS
 WARN_CFLAGS
+SYSTEM_GDBINIT_DIR
 SYSTEM_GDBINIT
 TARGET_SYSTEM_ROOT
 CONFIG_LDFLAGS
@@ -884,6 +885,7 @@ with_libipt_prefix
 with_included_regex
 with_sysroot
 with_system_gdbinit
+with_system_gdbinit_dir
 enable_werror
 enable_build_warnings
 enable_gdb_build_warnings
@@ -1618,6 +1620,9 @@ Optional Packages:
   --with-sysroot[=DIR]    search for usr/lib et al within DIR
   --with-system-gdbinit=PATH
                           automatically load a system-wide gdbinit file
+  --with-system-gdbinit-dir=PATH
+                          automatically load system-wide gdbinit files from
+                          this directory
   --with-lzma             support lzma compression (auto/yes/no)
   --with-liblzma-prefix[=DIR]  search for liblzma in DIR/include and DIR/lib
   --without-liblzma-prefix     don't search for liblzma in includedir and libdir
@@ -15238,6 +15243,52 @@ _ACEOF
 
 
 
+# Check whether --with-system-gdbinit-dir was given.
+if test "${with_system_gdbinit_dir+set}" = set; then :
+  withval=$with_system_gdbinit_dir;
+    SYSTEM_GDBINIT_DIR=$withval
+else
+  SYSTEM_GDBINIT_DIR=
+fi
+
+
+  test "x$prefix" = xNONE && prefix="$ac_default_prefix"
+  test "x$exec_prefix" = xNONE && exec_prefix='${prefix}'
+  ac_define_dir=`eval echo $SYSTEM_GDBINIT_DIR`
+  ac_define_dir=`eval echo $ac_define_dir`
+
+cat >>confdefs.h <<_ACEOF
+#define SYSTEM_GDBINIT_DIR "$ac_define_dir"
+_ACEOF
+
+
+
+
+  if test "x$exec_prefix" = xNONE || test "x$exec_prefix" = 'x${prefix}'; then
+     if test "x$prefix" = xNONE; then
+     	test_prefix=/usr/local
+     else
+	test_prefix=$prefix
+     fi
+  else
+     test_prefix=$exec_prefix
+  fi
+  value=0
+  case ${ac_define_dir} in
+     "${test_prefix}"|"${test_prefix}/"*|\
+	'${exec_prefix}'|'${exec_prefix}/'*)
+     value=1
+     ;;
+  esac
+
+cat >>confdefs.h <<_ACEOF
+#define SYSTEM_GDBINIT_DIR_RELOCATABLE $value
+_ACEOF
+
+
+
+
+
 # Check whether --enable-werror was given.
 if test "${enable_werror+set}" = set; then :
   enableval=$enable_werror; case "${enableval}" in
diff --git a/gdb/configure.ac b/gdb/configure.ac
index 9da8818fb5..f3f5bd0635 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1843,6 +1843,9 @@ GDB_AC_DEFINE_RELOCATABLE(TARGET_SYSTEM_ROOT, sysroot, ${ac_define_dir})
 GDB_AC_WITH_DIR(SYSTEM_GDBINIT, system-gdbinit,
     [automatically load a system-wide gdbinit file],
     [])
+GDB_AC_WITH_DIR(SYSTEM_GDBINIT_DIR, system-gdbinit-dir,
+    [automatically load system-wide gdbinit files from this directory],
+    [])
 
 AM_GDB_WARNINGS
 AM_GDB_UBSAN
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index f2713c0396..eb385ae1ee 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -1083,6 +1083,16 @@ Its location is specified with the @code{--with-system-gdbinit}
 configure option (@pxref{System-wide configuration}).
 It is loaded first when @value{GDBN} starts, before command line options
 have been processed.
+@item @file{system.gdbinit.d}
+This is the system-wide init directory.
+Its location is specified with the @code{--with-system-gdbinit-dir}
+configure option (@pxref{System-wide configuration}).
+Files in this directory are loaded in alphabetical order immediately after
+system.gdbinit (if enabled) when @value{GDBN} starts, before command line
+options have been processed.  Files need to have a recognized scripting
+language extension (@code{.py}/@code{.scm}) or be named with a @code{.gdb}
+extension to be interpreted as regular @value{GDBN} commands.  @value{GDBN}
+will not recurse into any subdirectories of this directory.
 @item @file{~/.gdbinit}
 This is the init file in your home directory.
 It is loaded next, after @file{system.gdbinit}, and before
@@ -1315,8 +1325,11 @@ Sets up the command interpreter as specified by the command line
 @cindex init file
 Reads the system-wide @dfn{init file} (if @option{--with-system-gdbinit} was
 used when building @value{GDBN}; @pxref{System-wide configuration,
- ,System-wide configuration and settings}) and executes all the commands in
-that file.
+ ,System-wide configuration and settings}) and the files in the system-wide
+gdbinit directory (if @option{--with-system-gdbinit-dir} was used) and executes
+all the commands in those files.  The files need to be named with a @code{.gdb}
+extension to be interpreted as @value{GDBN} commands, or they can be written
+in a supported scripting language with an appropriate file extension.
 
 @anchor{Home Directory Init File}
 @item
@@ -37034,6 +37047,14 @@ directory under the configured prefix, and @value{GDBN} is moved to
 another location after being built, the location of the system-wide
 init file will be adjusted accordingly.
 
+@item --with-system-gdbinit-dir=@var{directory}
+Configure @value{GDBN} to automatically load init files from a
+system-wide directory.  @var{directory} should be an absolute directory
+name.  If @var{directory} is in a directory under the configured
+prefix, and @value{GDBN} is moved to another location after being
+built, the location of the system-wide init directory will be
+adjusted accordingly.
+
 @item --enable-build-warnings
 When building the @value{GDBN} sources, ask the compiler to warn about
 any code which looks even vaguely suspicious.  It passes many
@@ -37059,24 +37080,28 @@ was first introduced in GCC 4.9.
 @section System-wide configuration and settings
 @cindex system-wide init file
 
-@value{GDBN} can be configured to have a system-wide init file;
-this file will be read and executed at startup (@pxref{Startup, , What
-@value{GDBN} does during startup}).
+@value{GDBN} can be configured to have a system-wide init file and a
+system-wide init file directory; this file and files in that directory
+(if they have a recognized file extension) will be read and executed at
+startup (@pxref{Startup, , What @value{GDBN} does during startup}).
 
-Here is the corresponding configure option:
+Here are the corresponding configure options:
 
 @table @code
 @item --with-system-gdbinit=@var{file}
 Specify that the default location of the system-wide init file is
 @var{file}.
+@item --with-system-gdbinit-dir=@var{directory}
+Specify that the default location of the system-wide init file directory
+is @var{directory}.
 @end table
 
 If @value{GDBN} has been configured with the option @option{--prefix=$prefix},
-it may be subject to relocation.  Two possible cases:
+they may be subject to relocation.  Two possible cases:
 
 @itemize @bullet
 @item 
-If the default location of this init file contains @file{$prefix},
+If the default location of this init file/directory contains @file{$prefix},
 it will be subject to relocation.  Suppose that the configure options
 are @option{--prefix=$prefix --with-system-gdbinit=$prefix/etc/gdbinit};
 if @value{GDBN} is moved from @file{$prefix} to @file{$install}, the system
@@ -37102,6 +37127,14 @@ initialization.  If the data-directory is changed after @value{GDBN} has
 started with the @code{set data-directory} command, the file will not be
 reread.
 
+This applies similarly to the system-wide directory specified in
+@option{--with-system-gdbinit-dir}.
+
+Any supported scripting language can be used for these init files, as long
+as the file extension matches the scripting language.  To be interpreted
+as regular @value{GDBN} commands, the files needs to have a @code{.gdb}
+extension.
+
 @menu
 * System-wide Configuration Scripts::  Installed System-wide Configuration Scripts
 @end menu
@@ -45591,6 +45624,10 @@ Richard M. Stallman and Roland H. Pesch, July 1991.
 @value{SYSTEM_GDBINIT}
 @end ifset
 
+@ifset SYSTEM_GDBINIT_DIR
+@value{SYSTEM_GDBINIT_DIR}/*
+@end ifset
+
 ~/.gdbinit
 
 ./.gdbinit
@@ -45632,6 +45669,20 @@ See more in
 the @value{GDBN} manual in node @code{System-wide configuration}
 -- shell command @code{info -f gdb -n 'System-wide configuration'}.
 @end ifset
+@ifset SYSTEM_GDBINIT_DIR
+@item @value{SYSTEM_GDBINIT_DIR}
+@end ifset
+@ifclear SYSTEM_GDBINIT_DIR
+@item (not enabled with @code{--with-system-gdbinit-dir} during compilation)
+@end ifclear
+System-wide initialization directory.  All files in this directory are
+executed on startup unless user specified @value{GDBN} option @code{-nx} or
+@code{-n}, as long as they have a recognized file extension.
+See more in
+@ifset man
+the @value{GDBN} manual in node @code{System-wide configuration}
+-- shell command @code{info -f gdb -n 'System-wide configuration'}.
+@end ifset
 @ifclear man
 @ref{System-wide configuration}.
 @end ifclear
diff --git a/gdb/extension.c b/gdb/extension.c
index 8637bc53f2..1fb4b48003 100644
--- a/gdb/extension.c
+++ b/gdb/extension.c
@@ -154,6 +154,9 @@ get_ext_lang_of_file (const char *file)
   int i;
   const struct extension_language_defn *extlang;
 
+  if (has_extension (file, extension_language_gdb.suffix))
+    return &extension_language_gdb;
+
   ALL_EXTENSION_LANGUAGES (i, extlang)
     {
       if (has_extension (file, extlang->suffix))
diff --git a/gdb/main.c b/gdb/main.c
index 7fab8ff8da..ed902371cb 100644
--- a/gdb/main.c
+++ b/gdb/main.c
@@ -45,6 +45,7 @@
 #include "event-top.h"
 #include "infrun.h"
 #include "gdbsupport/signals-state-save-restore.h"
+#include <algorithm>
 #include <vector>
 #include "gdbsupport/pathstuff.h"
 #include "cli/cli-style.h"
@@ -195,7 +196,8 @@ relocate_gdb_directory (const char *initial, bool relocatable)
    otherwise.  */
 
 static std::string
-relocate_gdbinit_path_maybe_in_datadir (const std::string& file)
+relocate_gdbinit_path_maybe_in_datadir (const std::string& file,
+					bool relocatable)
 {
   size_t datadir_len = strlen (GDB_DATADIR);
 
@@ -219,9 +221,8 @@ relocate_gdbinit_path_maybe_in_datadir (const std::string& file)
     }
   else
     {
-      relocated_path = relocate_path (gdb_program_name,
-				      file.c_str (),
-				      SYSTEM_GDBINIT_RELOCATABLE);
+      relocated_path = relocate_path (gdb_program_name, file.c_str (),
+				      relocatable);
     }
     return relocated_path;
 }
@@ -232,11 +233,11 @@ relocate_gdbinit_path_maybe_in_datadir (const std::string& file)
    to be loaded, then SYSTEM_GDBINIT (resp. HOME_GDBINIT and
    LOCAL_GDBINIT) is set to the empty string.  */
 static void
-get_init_files (std::string *system_gdbinit,
+get_init_files (std::vector<std::string> *system_gdbinit,
 		std::string *home_gdbinit,
 		std::string *local_gdbinit)
 {
-  static std::string sysgdbinit;
+  static std::vector<std::string> sysgdbinit;
   static std::string homeinit;
   static std::string localinit;
   static int initialized = 0;
@@ -248,10 +249,49 @@ get_init_files (std::string *system_gdbinit,
       if (SYSTEM_GDBINIT[0])
 	{
 	  std::string relocated_sysgdbinit
-	    = relocate_gdbinit_path_maybe_in_datadir (SYSTEM_GDBINIT);
+	    = relocate_gdbinit_path_maybe_in_datadir
+		(SYSTEM_GDBINIT, SYSTEM_GDBINIT_RELOCATABLE);
 	  if (!relocated_sysgdbinit.empty ()
 	      && stat (relocated_sysgdbinit.c_str (), &s) == 0)
-	    sysgdbinit = relocated_sysgdbinit;
+	    sysgdbinit.push_back (relocated_sysgdbinit);
+	}
+      if (SYSTEM_GDBINIT_DIR[0])
+	{
+	  std::string relocated_gdbinit_dir
+	    = relocate_gdbinit_path_maybe_in_datadir
+		(SYSTEM_GDBINIT_DIR, SYSTEM_GDBINIT_DIR_RELOCATABLE);
+	  DIR *dir = nullptr;
+	  if (!relocated_gdbinit_dir.empty ())
+	    dir = opendir (relocated_gdbinit_dir.c_str ());
+	  if (dir != nullptr)
+	    {
+	      std::vector<std::string> files;
+	      struct dirent *ent;
+	      for (;;)
+		{
+		  ent = readdir (dir);
+		  if (ent == nullptr)
+		    break;
+		  if (ent->d_name[0] == '.')
+		    continue;
+		  /* ent->d_type is not available on all systems (e.g. mingw,
+		     Solaris), so we have to call stat().  */
+		  std::string filename
+		    = relocated_gdbinit_dir + SLASH_STRING + ent->d_name;
+		  if (stat(filename.c_str (), &s) != 0 || !S_ISREG (s.st_mode))
+		    continue;
+		  const struct extension_language_defn *extlang
+		    = get_ext_lang_of_file (filename.c_str ());
+		  /* We effectively don't support "set script-extension off/soft",
+		     because we are loading system init files here, so it
+		     does not really make sense to depend on a setting.  */
+		  if (extlang != nullptr && ext_lang_present_p (extlang))
+		    files.push_back (filename);
+		}
+	      closedir (dir);
+	      std::sort (files.begin (), files.end ());
+	      sysgdbinit.insert (sysgdbinit.end (), files.begin (), files.end ());
+	    }
 	}
 
       const char *homedir = getenv ("HOME");
@@ -916,7 +956,7 @@ captured_main_1 (struct captured_main_args *context)
   /* Lookup gdbinit files.  Note that the gdbinit file name may be
      overriden during file initialization, so get_init_files should be
      called after gdb_init.  */
-  std::string system_gdbinit;
+  std::vector<std::string> system_gdbinit;
   std::string home_gdbinit;
   std::string local_gdbinit;
   get_init_files (&system_gdbinit, &home_gdbinit, &local_gdbinit);
@@ -996,7 +1036,10 @@ captured_main_1 (struct captured_main_args *context)
      processed; it sets global parameters, which are independent of
      what file you are debugging or what directory you are in.  */
   if (!system_gdbinit.empty () && !inhibit_gdbinit)
-    ret = catch_command_errors (source_script, system_gdbinit.c_str (), 0);
+    {
+      for (const std::string& file : system_gdbinit)
+	ret = catch_command_errors (source_script, file.c_str (), 0);
+    }
 
   /* Read and execute $HOME/.gdbinit file, if it exists.  This is done
      *before* all the command line arguments are processed; it sets
@@ -1214,7 +1257,7 @@ gdb_main (struct captured_main_args *args)
 static void
 print_gdb_help (struct ui_file *stream)
 {
-  std::string system_gdbinit;
+  std::vector<std::string> system_gdbinit;
   std::string home_gdbinit;
   std::string local_gdbinit;
 
@@ -1295,9 +1338,18 @@ Other options:\n\n\
 At startup, GDB reads the following init files and executes their commands:\n\
 "), stream);
   if (!system_gdbinit.empty ())
-    fprintf_unfiltered (stream, _("\
-   * system-wide init file: %s\n\
-"), system_gdbinit.c_str ());
+    {
+      std::string output;
+      for (size_t idx = 0; idx < system_gdbinit.size (); ++idx)
+        {
+	  output += system_gdbinit[idx];
+	  if (idx < system_gdbinit.size () - 1)
+	    output += ", ";
+	}
+      fprintf_unfiltered (stream, _("\
+   * system-wide init files: %s\n\
+"), output.c_str ());
+    }
   if (!home_gdbinit.empty ())
     fprintf_unfiltered (stream, _("\
    * user-specific init file: %s\n\
diff --git a/gdb/top.c b/gdb/top.c
index 49e6daae94..7a45f1b4aa 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -1515,6 +1515,10 @@ This GDB was configured as follows:\n\
     fprintf_filtered (stream, _("\
              --with-system-gdbinit=%s%s\n\
 "), SYSTEM_GDBINIT, SYSTEM_GDBINIT_RELOCATABLE ? " (relocatable)" : "");
+  if (SYSTEM_GDBINIT_DIR[0])
+    fprintf_filtered (stream, _("\
+             --with-system-gdbinit-dir=%s%s\n\
+"), SYSTEM_GDBINIT_DIR, SYSTEM_GDBINIT_DIR_RELOCATABLE ? " (relocatable)" : "");
     /* We assume "relocatable" will be printed at least once, thus we always
        print this text.  It's a reasonably safe assumption for now.  */
     fprintf_filtered (stream, _("\n\
-- 
2.23.0.351.gc4317032e6-goog