* Add support of variables and variable substitution in config file

cfg_file.h

@@ -114,6 +114,7 @@ struct config_file {
 	LIST_HEAD (modulesq, perl_module) perl_modules;
 	LIST_HEAD (cmodulesq, c_module) c_modules;
 	GHashTable* modules_opts;
+	GHashTable* variables;
 };
 
 int add_memcached_server (struct config_file *cf, char *str);
@@ -125,6 +126,8 @@ char* get_module_opt (struct config_file *cfg, char *module_name, char *opt_name
 size_t parse_limit (const char *limit);
 unsigned int parse_seconds (const char *t);
 char parse_flag (const char *str);
+char* substitute_variable (struct config_file *cfg, char *str, u_char recursive);
+void post_load_config (struct config_file *cfg);
 
 int yylex (void);
 int yyparse (void);

cfg_file.l

@@ -13,6 +13,7 @@
 #define MAX_INCLUDE_DEPTH 10
 YY_BUFFER_STATE include_stack[MAX_INCLUDE_DEPTH];
 int include_stack_ptr = 0;
+extern struct config_file *cfg;
 
 %}
 
@@ -45,7 +46,6 @@ script_message					return SCRIPT_MESSAGE;
 script_url						return SCRIPT_URL;
 script_chain					return SCRIPT_CHAIN;
 
-
 \{								return OBRACE;
 \}								return EBRACE;
 ;								return SEMICOLON;
@@ -56,6 +56,7 @@ yes|YES|no|NO|[yY]|[nN]			yylval.flag=parse_flag(yytext); return FLAG;
 [ \t]+							/* ignore whitespace */;
 \"[^"]+\"						yylval.string=strdup(yytext + 1); yylval.string[strlen(yylval.string) - 1] = '\0'; return QUOTEDSTRING;
 \"								return QUOTE;
+\$[a-zA-Z_][a-zA-Z0-9_]+		yylval.string=strdup(yytext + 1); return VARIABLE;
 [0-9]+							yylval.number=strtol(yytext, NULL, 10); return NUMBER;
 [0-9]+[kKmMgG]?					yylval.limit=parse_limit(yytext); return SIZELIMIT;
 [0-9]+[sS]|[0-9]+[mM][sS]		yylval.seconds=parse_seconds(yytext); return SECONDS;
@@ -68,38 +69,34 @@ yes|YES|no|NO|[yY]|[nN]			yylval.flag=parse_flag(yytext); return FLAG;
 [a-zA-Z0-9].[a-zA-Z0-9\/.-]+	yylval.string=strdup(yytext); return DOMAIN;
 <incl>[ \t]*      /* eat the whitespace */
 <incl>[^ \t\n]+   { /* got the include file name */
-        if ( include_stack_ptr >= MAX_INCLUDE_DEPTH ) {
-            yyerror ("yylex: includes nested too deeply" );
+        if (include_stack_ptr >= MAX_INCLUDE_DEPTH) {
+            yyerror ("yylex: includes nested too deeply");
             return -1;
         }
 
         include_stack[include_stack_ptr++] =
             YY_CURRENT_BUFFER;
 
-        yyin = fopen( yytext, "r" );
+        yyin = fopen (yytext, "r");
 
-        if ( ! yyin ) {
-            yyerror("yylex: cannot open include file");
+        if (! yyin) {
+            yyerror ("yylex: cannot open include file");
 			return -1;
 		}
 
-        yy_switch_to_buffer(
-            yy_create_buffer( yyin, YY_BUF_SIZE ) );
+        yy_switch_to_buffer (yy_create_buffer (yyin, YY_BUF_SIZE));
 
         BEGIN(INITIAL);
         }
 
 <<EOF>> {
-        if ( --include_stack_ptr < 0 )
-            {
-            yyterminate();
-            }
-
-        else
-            {
-            yy_delete_buffer( YY_CURRENT_BUFFER );
-            yy_switch_to_buffer(
-                 include_stack[include_stack_ptr] );
+        if ( --include_stack_ptr < 0 ) {
+			post_load_config (cfg);
+            yyterminate ();
+        }
+        else {
+            yy_delete_buffer (YY_CURRENT_BUFFER);
+            yy_switch_to_buffer (include_stack[include_stack_ptr]);
             }
         }
 
@@ -110,6 +107,7 @@ yes|YES|no|NO|[yY]|[nN]			yylval.flag=parse_flag(yytext); return FLAG;
 <module>\}  return EBRACE;
 <module>\;	return SEMICOLON;
 <module>[a-zA-Z0-9_-]	yylval.string=strdup(yytext); return PARAM;
+<module>\$[a-zA-Z_][a-zA-Z0-9_]+		yylval.string=strdup(yytext + 1); return VARIABLE;
 <module>\"[^"]+\"	yylval.string=strdup(yytext + 1); yylval.string[strlen(yylval.string) - 1] = '\0'; return QUOTEDSTRING;
 
 %%

cfg_file.y

@@ -48,9 +48,10 @@ LIST_HEAD (moduleoptq, module_opt) *cur_module_opt = NULL;
 %token  READ_SERVERS WRITE_SERVER DIRECTORY_SERVERS MAILBOX_QUERY USERS_QUERY LASTLOGIN_QUERY
 %token  MEMCACHED WORKERS REQUIRE MODULE
 %token  FILTER METRIC SCRIPT_HEADER SCRIPT_MIME SCRIPT_MESSAGE SCRIPT_URL SCRIPT_CHAIN SCRIPT_PARAM
-%token  MODULE_OPT, PARAM
+%token  MODULE_OPT PARAM VARIABLE
 
 %type	<string>	STRING
+%type	<string>	VARIABLE
 %type	<string>	QUOTEDSTRING MODULE_OPT PARAM
 %type	<string>	FILENAME 
 %type   <string>  	SOCKCRED
@@ -80,6 +81,7 @@ command	:
 	| require
 	| filter
 	| module_opt
+	| variable
 	;
 
 tempdir :
@@ -403,6 +405,12 @@ optcmd:
 	}
 	;
 
+variable:
+	VARIABLE EQSIGN QUOTEDSTRING {
+		g_hash_table_insert (cfg->variables, $1, $3);
+	}
+	;
+
 %%
 /* 
  * vi:ts=4 

cfg_utils.c

@@ -149,6 +149,7 @@ init_defaults (struct config_file *cfg)
 
 	cfg->workers_number = DEFAULT_WORKERS_NUM;
 	cfg->modules_opts = g_hash_table_new (g_str_hash, g_str_equal);
+	cfg->variables = g_hash_table_new (g_str_hash, g_str_equal);
 
 	LIST_INIT (&cfg->filters);
 	LIST_INIT (&cfg->perl_modules);
@@ -205,6 +206,8 @@ free_config (struct config_file *cfg)
 	g_hash_table_foreach (cfg->modules_opts, clean_hash_bucket, NULL);
 	g_hash_table_remove_all (cfg->modules_opts);
 	g_hash_table_unref (cfg->modules_opts);
+	g_hash_table_remove_all (cfg->variables);
+	g_hash_table_unref (cfg->variables);
 }
 
 int
@@ -323,6 +326,81 @@ parse_flag (const char *str)
 	return -1;
 }
 
+/*
+ * Try to substitute all variables in given string
+ * Return: newly allocated string with substituted variables (original string may be freed if variables are found)
+ */
+char *
+substitute_variable (struct config_file *cfg, char *str, u_char recursive)
+{
+	char *var, *new, *v_begin, *v_end;
+	size_t len;
+
+	while ((v_begin = strstr (str, "${")) != NULL) {
+		len = strlen (str);
+		*v_begin = '\0';
+		v_begin += 2;
+		if ((v_end = strstr (v_begin, "}")) == NULL) {
+			/* Not a variable, skip */
+			continue;
+		}
+		*v_end = '\0';
+		var = g_hash_table_lookup (cfg->variables, v_begin);
+		if (var == NULL) {
+			yywarn ("substitute_variable: variable %s is not defined", v_begin);
+			/* Substitute unknown variables with empty string */
+			var = "";
+		}
+		else if (recursive) {
+			var = substitute_variable (cfg, var, recursive);
+		}
+		/* Allocate new string */
+		new = g_malloc (len - strlen (v_begin) + strlen (var) + 1);
+
+		snprintf (new, len - strlen (v_begin) + strlen (var) + 1, "%s%s%s",
+						str, var, v_end + 1);
+		g_free (str);
+		str = new;
+	}
+
+	return str;
+}
+
+static void
+substitute_module_variables (gpointer key, gpointer value, gpointer data)
+{
+	struct config_file *cfg = (struct config_file *)data;
+	LIST_HEAD (moduleoptq, module_opt) *cur_module_opt = (struct moduleoptq *)value;
+	struct module_opt *cur, *tmp;
+
+	LIST_FOREACH_SAFE (cur, cur_module_opt, next, tmp) {
+		if (cur->value) {
+			cur->value = substitute_variable (cfg, cur->value, 0);
+		}
+	}
+}
+
+static void
+substitute_all_variables (gpointer key, gpointer value, gpointer data)
+{
+	struct config_file *cfg = (struct config_file *)data;
+	char *var;
+
+	var = value;
+	/* Do recursive substitution */
+	var = substitute_variable (cfg, var, 1);
+}
+
+/* 
+ * Substitute all variables in strings
+ */
+void
+post_load_config (struct config_file *cfg)
+{
+	g_hash_table_foreach (cfg->variables, substitute_all_variables, cfg);
+	g_hash_table_foreach (cfg->modules_opts, substitute_module_variables, cfg);
+}
+
 /*
  * vi:ts=4
  */