Make econfig keys data and info work for relative names

File names in econfig need to be interpreted relative to configdir.
This wasn't the case everywhere for keys data and info.

Fix this by changing variables gamedir and infodir to hold absolute
names.  Change builtindir likewise, for consistency.  Store the values
from econfig in gamedir_conf, infodir_conf and builtindir_conf.

Uses new fnameat() to derive absolute names from possibly relative
ones.

include/econfig-spec.h

@@ -73,17 +73,13 @@ EMPCFBOTH((fvname), (vname), int, NSC_INT, KM_OPTION, (descr))
 EMPCF_COMMENT("\n### Server configuration and information")
 EMPCFBOTH("custom_tables", custom_tables, char *, NSC_STRING, KM_INTERNAL,
     "Custom configuration table files, separated by space")
-EMPCFBOTH("data", gamedir, char *, NSC_STRING, KM_INTERNAL,
+EMPCFBOTH("data", gamedir_conf, char *, NSC_STRING, KM_INTERNAL,
     "Directory where this game's data is stored")
-EMPCF_COMMENT("# Note: Use an absolute name here, the interpretation of a relative\n"
-	      "# name may change.")
-EMPCFBOTH("info", infodir, char *, NSC_STRING, KM_INTERNAL,
+EMPCFBOTH("info", infodir_conf, char *, NSC_STRING, KM_INTERNAL,
     "Directory where info pages are stored, can be shared among games")
 EMPCF_COMMENT("# Set this to your build tree's info.nr to run the server without\n"
-	      "# installing it.\n"
-	      "# Note: Use an absolute name here, the interpretation of a relative\n"
-	      "# name may change.")
-EMPCFBOTH("builtin", builtindir, char *, NSC_STRING, KM_INTERNAL,
+	      "# installing it.")
+EMPCFBOTH("builtin", builtindir_conf, char *, NSC_STRING, KM_INTERNAL,
     "Directory where builtin files are stored")
 EMPCF_COMMENT("# Set this to your source tree's src/lib/global to run the server\n"
 	      "# without installing it, else leave it alone.")

include/optlist.h

@@ -45,6 +45,9 @@ extern char dflt_econfig[];
 #undef	EMP_CONFIG_H_OUTPUT
 
 extern char *configdir;
+extern char *builtindir;
+extern char *gamedir;
+extern char *infodir;
 extern char *schedulefil;
 
 extern char motdfil[];

include/prototypes.h

@@ -321,6 +321,8 @@ extern int xundump(FILE *, char *, int *, int);
 /*
  * src/lib/gen/ *.c 
  */
+/* fnameat.c */
+extern char *fnameat(const char *, const char *);
 /* fsize.c */
 extern int fsize(int);
 extern int blksize(int);

src/lib/common/emp_config.c

@@ -201,8 +201,10 @@ set_paths(char *econfig)
     }
 #endif /* !_WIN32 */
 
-    schedulefil = malloc(strlen(configdir) + 10);
-    sprintf(schedulefil, "%s/schedule", configdir);
+    infodir = fnameat(infodir_conf, configdir);
+    gamedir = fnameat(gamedir_conf, configdir);
+    builtindir = fnameat(builtindir_conf, configdir);
+    schedulefil = fnameat("schedule", configdir);
 
     free(cwd);
 }

src/lib/gen/fnameat.c

@@ -0,0 +1,73 @@
+/*
+ *  Empire - A multi-player, client/server Internet based war game.
+ *  Copyright (C) 1986-2008, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ *                           Ken Stevens, Steve McClure
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  ---
+ *
+ *  See files README, COPYING and CREDITS in the root of the source
+ *  tree for related information and legal notices.  It is expected
+ *  that future projects/authors will amend these files as needed.
+ *
+ *  ---
+ *
+ *  fnameat.c: Interpret file names relative to a directory
+ * 
+ *  Known contributors to this file:
+ *     Markus Armbruster, 2008
+ */
+
+#include <config.h>
+
+#include <errno.h>
+#include "prototypes.h"
+
+static int fname_is_abs(const char *);
+
+/*
+ * Interpret FNAME relative to directory DIR.
+ * Return FNAME if it is absolute, or DIR is null or empty.
+ * Else return a malloc'ed string containing DIR/FNAME, or null
+ * pointer when that fails.
+ */
+char *
+fnameat(const char *fname, const char *dir)
+{
+    char *res;
+
+    if (fname_is_abs(fname) || !dir || !*dir)
+	return (char *)fname;
+
+    res = malloc(strlen(dir) + 1 + strlen(fname) + 1);
+    if (!res)
+	return NULL;
+
+    sprintf(res, "%s/%s", dir, fname);
+    return res;
+}
+
+static int
+fname_is_abs(const char *fname)
+{
+#ifdef _WIN32
+    /* Treat as absolute if it starts with '/', '\\' or a drive */
+    return fname[0] == '/' || fname[0] == '\\'
+	|| (fname[0] != 0 && fname[1] == ':');
+#else
+    return fname[0] == '/';
+#endif
+}

src/lib/global/path.c.in

@@ -53,15 +53,19 @@ char *custom_tables = "";
 char *schedulefil;
 
 /* Where to find built-in configuration tables (relative to configdir) */
+char *builtindir_conf = "@builtindir@";
+/* Where to find built-in configuration tables (absolute) */
 char *builtindir = "@builtindir@";
 
-/* Where to find info pages (relative to gamedir) */
-/* TODO UI wart, make it relative to configdir */
-char *infodir	= "@einfodir@";
+/* Where to find info pages (relative to configdir) */
+char *infodir_conf = "@einfodir@";
+/* Where to find info pages (absolute) */
+char *infodir;
 
 /* Where this game's data is stored (relative to configdir) */
-/* FIXME relative broken in utility programs */
-char *gamedir	= "@gamedir@";
+char *gamedir_conf = "@gamedir@";
+/* Where this game's data is stored (absolute) */
+char *gamedir;
 
 /* These are relative to gamedir: */
 char teldir[]	= "tel";