[PATCH] Try to initialize data-directory by first searching for "data-directory" in the same directory as the gdb binary

[Khoo Yit Phang <khooyp@cs.umd.edu>]

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Hi,

As discussed previously, here a patch that tries to initialize data-directory by first searching for "data-directory" in the same directory as the gdb binary. Additionally, I've also reverted my previous change to cc-with-tweaks.sh that added the -data-directory flag, since it is no longer necessary.

Thank you,

Yit
September 18, 2012



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gdb/ChangeLog

2012-09-18  Khoo Yit Phang  <khooyp@cs.umd.edu>

	Try to initialize data-directory by first searching for
	"data-directory" in the same directory as the gdb binary.
	* contrib/cc-with-tweaks.sh (GDB): Revert -data-directory
	additions that is now unnecessary.
	* main.c (relocate_path): Add an isdir argument, and check that
	the relocated file/directory exists.
	(relocate_gdb_directory): Remove the directory check that is
	subsumed by relocate_path.
	(get_init_files): Remove the file check that is subsumed by
	relocate_path.
	(relocate_gdb_data_directory): New function similar to
	relocate_gdb_directory, but specifically for data-directory.
	(captured_main): Call relocate_gdb_data_directory to initialize
	gdb_datadir.

diff --git a/gdb/contrib/cc-with-tweaks.sh b/gdb/contrib/cc-with-tweaks.sh
--- a/gdb/contrib/cc-with-tweaks.sh
+++ b/gdb/contrib/cc-with-tweaks.sh
@@ -19,8 +19,7 @@
 # This program requires gdb and objcopy in addition to gcc.
 # The default values are gdb from the build tree and objcopy from $PATH.
 # They may be overridden by setting environment variables GDB and OBJCOPY
-# respectively.  Note that GDB should contain the gdb binary as well as the
-# -data-directory flag, e.g., "foo/gdb -data-directory foo/data-directory".
+# respectively.
 # We assume the current directory is either $obj/gdb or $obj/gdb/testsuite.
 #
 # Example usage:
@@ -47,13 +46,13 @@
 then
     if [ -f ./gdb ]
     then
-	GDB="./gdb -data-directory data-directory"
+	GDB="./gdb"
     elif [ -f ../gdb ]
     then
-	GDB="../gdb -data-directory ../data-directory"
+	GDB="../gdb"
     elif [ -f ../../gdb ]
     then
-	GDB="../../gdb -data-directory ../../data-directory"
+	GDB="../../gdb"
     else
 	echo "$myname: unable to find usable gdb" >&2
 	exit 1
diff --git a/gdb/main.c b/gdb/main.c
--- a/gdb/main.c
+++ b/gdb/main.c
@@ -91,17 +91,34 @@
 
 static void print_gdb_help (struct ui_file *);
 
-/* 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
-   otherwise.  Returns a newly allocated string; this may return NULL
-   under the same conditions as make_relative_prefix.  */
+/* Relocate a file or directory, checking if it exists.  PROGNAME is the
+   name by which gdb was invoked (i.e., argv[0]).  INITIAL is the default
+   value for the file or directory.  ISDIR is true if INITIAL is a
+   directory.  FLAG is true if the value is relocatable, false otherwise.
+   Returns a newly allocated string; this may return NULL under the same
+   conditions as make_relative_prefix, or if the relocated path does not
+   exist.  */
 
 static char *
-relocate_path (const char *progname, const char *initial, int flag)
+relocate_path (const char *progname, const char *initial, int isdir,
+	       int flag)
 {
   if (flag)
-    return make_relative_prefix (progname, BINDIR, initial);
+    {
+      char *path;
+      path = make_relative_prefix (progname, BINDIR, initial);
+      if (path)
+	{
+	  struct stat s;
+
+	  if (stat (path, &s) != 0 || (isdir && !S_ISDIR (s.st_mode)))
+	    {
+	      xfree (path);
+	      path = NULL;
+	    }
+	}
+      return path;
+    }
   return xstrdup (initial);
 }
 
@@ -116,19 +133,52 @@
 {
   char *dir;
 
-  dir = relocate_path (gdb_program_name, initial, flag);
-  if (dir)
+  dir = relocate_path (gdb_program_name, initial, 1, flag);
+  if (!dir)
+    dir = xstrdup (initial);
+
+  /* Canonicalize the directory.  */
+  if (*dir)
     {
-      struct stat s;
+      char *canon_sysroot = lrealpath (dir);
 
-      if (stat (dir, &s) != 0 || !S_ISDIR (s.st_mode))
+      if (canon_sysroot)
 	{
 	  xfree (dir);
-	  dir = NULL;
+	  dir = canon_sysroot;
 	}
     }
+
+  return dir;
+}
+
+/* Like relocate_gdb_path, but specifically for data-directory. */
+
+static char *
+relocate_gdb_data_directory (void)
+{
+  char *dir;
+
+  /* First try to find "data-directory" in the same directory as gdb.
+
+    Use relocate_path only to resolve the parent directory of
+    gdb_program_name (i.e., based on PATH if necessary); relocate_path
+    (gdb_program_name, BINDIR "/data-directory") cannot be used to resolve
+    data-directory as it returns a path relative to the _grandparent
+    directory_ of gdb_program_name (munging the parent directory).  */
+
+  dir = relocate_path (gdb_program_name, BINDIR, 1, 1);
+  if (dir)
+    dir = reconcat (dir, dir, SLASH_STRING, "data-directory", NULL);
+
+  /* Then try to find GDB_DATADIR relocated relative to gdb. */
   if (!dir)
-    dir = xstrdup (initial);
+    dir = relocate_path (gdb_program_name, GDB_DATADIR, 1,
+			 GDB_DATADIR_RELOCATABLE);
+
+  /* Otherwise use GDB_DATADIR as is. */
+  if (!dir)
+    dir = xstrdup (GDB_DATADIR);
 
   /* Canonicalize the directory.  */
   if (*dir)
@@ -162,15 +212,15 @@
 
   if (!initialized)
     {
-      struct stat homebuf, cwdbuf, s;
+      struct stat homebuf, cwdbuf;
       char *homedir, *relocated_sysgdbinit;
 
       if (SYSTEM_GDBINIT[0])
 	{
 	  relocated_sysgdbinit = relocate_path (gdb_program_name,
-						SYSTEM_GDBINIT,
+						SYSTEM_GDBINIT, 0,
 						SYSTEM_GDBINIT_RELOCATABLE);
-	  if (relocated_sysgdbinit && stat (relocated_sysgdbinit, &s) == 0)
+	  if (relocated_sysgdbinit)
 	    sysgdbinit = relocated_sysgdbinit;
 	  else
 	    xfree (relocated_sysgdbinit);
@@ -363,8 +413,7 @@
   debug_file_directory = relocate_gdb_directory (DEBUGDIR,
 						 DEBUGDIR_RELOCATABLE);
 
-  gdb_datadir = relocate_gdb_directory (GDB_DATADIR,
-					GDB_DATADIR_RELOCATABLE);
+  gdb_datadir = relocate_gdb_data_directory ();
 
 #ifdef WITH_PYTHON_PATH
   {