wmmenugen: Add executable detection, make Wmconfig use it

Add fileInPath, which determines whether or not a given file exists
in $PATH (some heuristics apply).

Make the Wconfig parser use it.

Signed-off-by: Tamas TEVESZ <ice@extreme.hu>

util/wmmenugen.h

@@ -51,6 +51,7 @@ char *env_lang, *env_ctry, *env_enc, *env_mod;
  */
 void  parse_locale(const char *what, char **env_lang, char **env_ctry, char **env_enc, char **env_mod);
 char *find_terminal_emulator(void);
+Bool fileInPath(const char *file);
 
 /* implemented parsers
  */

util/wmmenugen_misc.c

@@ -124,3 +124,48 @@ out:
 	return;
 
 }
+
+/* determine whether (first token of) given file is in $PATH
+ */
+Bool fileInPath(const char *file)
+{
+	char *p, *t;
+	static char *path = NULL;
+
+	if (!file || !*file)
+		return False;
+
+	/* if it's an absolute path spec, don't override the user.
+	 * s/he might just know better.
+	 */
+	if (*file == '/')
+		return True;
+
+	/* if it has a directory separator at random places,
+	 * we might know better.
+	 */
+	p = strchr(file, '/');
+	if (p)
+		return False;
+
+	if (!path) {
+		path = getenv("PATH");
+		if (!path)
+			return False;
+	}
+
+	p = wstrdup(file);
+	t = strpbrk(p, " \t");
+	if (t)
+		*t = '\0';
+
+	t = wfindfile(path, p);
+	wfree(p);
+
+	if (t) {
+		wfree(t);
+		return True;
+	}
+
+	return False;
+}

util/wmmenugen_parse_wmconfig.c

@@ -185,8 +185,10 @@ static Bool wmc_to_wm(WMConfigMenuEntry **wmc, WMMenuEntry **wm)
 	char *p;
 	size_t slen;
 
-	/* only Exec is mandatory */
-	if (!*wmc || !(*wmc)->Exec || !*(*wmc)->Exec)
+	/* only Exec is mandatory, and it's better exist in a known place */
+	if (!*wmc ||
+	    !(*wmc)->Exec || !*(*wmc)->Exec ||
+	    !fileInPath((*wmc)->Exec))
 		return False;
 
 	/* normalize Exec: wmconfig tends to stuck an ampersand