Treat literal strings as constant

Literal strings are located in read-only memory and should be "const
char*".  "gcc -Wwrite-strings" warns when using non-const literal
strings with messages like:

    libqpol/policy_parse.y: In function 'yyparse':
    libqpol/policy_parse.y:381:21: warning: passing argument 1 of
    'insert_id' discards 'const' qualifier from pointer target type
         { if (insert_id("T",0)) return -1; }
                     ^

Fix these warnings by using "const char*" instead of "char*" for some
function parameters.

This makes gcc report other warnings about hashtab_search (from
libsepol).  This function incorrectly defines its second parameter as
"char *const key" instead of "const char* key" (this fact is hidden
behind hashtab_key_t typedef).

libqpol/module_compiler.c

@@ -1253,7 +1253,7 @@ static int is_scope_in_stack(scope_datum_t * scope, scope_stack_t * stack)
 	return is_scope_in_stack(scope, stack->parent);
 }
 
-int is_id_in_scope(uint32_t symbol_type, hashtab_key_t id)
+int is_id_in_scope(uint32_t symbol_type, const char *id)
 {
 	scope_datum_t *scope =
 	    (scope_datum_t *) hashtab_search(policydbp->scope[symbol_type].
@@ -1300,7 +1300,7 @@ static int is_perm_in_stack(uint32_t perm_value, uint32_t class_value,
 	return is_perm_in_stack(perm_value, class_value, stack->parent);
 }
 
-int is_perm_in_scope(hashtab_key_t perm_id, hashtab_key_t class_id)
+int is_perm_in_scope(hashtab_key_t perm_id, const char *class_id)
 {
 	class_datum_t *cladatum =
 	    (class_datum_t *) hashtab_search(policydbp->p_classes.table,

libqpol/module_compiler.h

@@ -76,12 +76,12 @@ int require_cat(int pass);
 /* Check if an identifier is within the scope of the current
  * declaration or any of its parents.  Return 1 if it is, 0 if not.
  * If the identifier is not known at all then return 1 (truth).  */
-int is_id_in_scope(uint32_t symbol_type, hashtab_key_t id);
+int is_id_in_scope(uint32_t symbol_type, const char * id);
 
 /* Check if a particular permission is within the scope of the current
  * declaration or any of its parents.  Return 1 if it is, 0 if not.
  * If the identifier is not known at all then return 1 (truth).  */
-int is_perm_in_scope(hashtab_key_t perm_id, hashtab_key_t class_id);
+int is_perm_in_scope(hashtab_key_t perm_id, const char * class_id);
 
 /* Search the current avrules block for a conditional with the same
  * expression as 'cond'.  If the conditional does not exist then

libqpol/policy.c

@@ -177,7 +177,7 @@ static void qpol_handle_default_callback(void *varg __attribute__ ((unused)), co
 	fprintf(stderr, "\n");
 }
 
-static int read_source_policy(qpol_policy_t * qpolicy, char *progname, int options)
+static int read_source_policy(qpol_policy_t * qpolicy, const char *progname, int options)
 {
 	int load_rules = 1;
 	if (options & QPOL_POLICY_OPTION_NO_RULES)

libqpol/policy_define.c

@@ -87,7 +87,7 @@ extern int yyerror(const char *msg);
 #define ERRORMSG_LEN 255
 static char errormsg[ERRORMSG_LEN + 1] = {0};
 
-static int id_has_dot(char *id);
+static int id_has_dot(const char *id);
 static int parse_security_context(context_struct_t *c);
 
 /* initialize all of the state variables for the scanner/parser */
@@ -167,7 +167,7 @@ int insert_separator(int push)
 	return 0;
 }
 
-int insert_id(char *id, int push)
+int insert_id(const char *id, int push)
 {
 	char *newid = 0;
 	int error;
@@ -193,7 +193,7 @@ int insert_id(char *id, int push)
 
 /* If the identifier has a dot within it and that its first character
    is not a dot then return 1, else return 0. */
-static int id_has_dot(char *id)
+static int id_has_dot(const char *id)
 {
 	if (strchr(id, '.') >= id + 1) {
 		return 1;
@@ -1380,7 +1380,7 @@ int define_typeattribute(void)
 	return 0;
 }
 
-static int define_typebounds_helper(char *bounds_id, char *type_id)
+static int define_typebounds_helper(const char *bounds_id, const char *type_id)
 {
 	type_datum_t *bounds, *type;
 

libqpol/policy_define.h

@@ -77,7 +77,7 @@ int define_typebounds(void);
 int define_type(int alias);
 int define_user(void);
 int define_validatetrans(constraint_expr_t *expr);
-int insert_id(char *id,int push);
+int insert_id(const char *id,int push);
 int insert_separator(int push);
 role_datum_t *define_role_dom(role_datum_t *r);
 role_datum_t *merge_roles_dom(role_datum_t *r1,role_datum_t *r2);

libqpol/policy_extend.c

@@ -367,7 +367,7 @@ static int qpol_policy_fill_attr_holes(qpol_policy_t * policy)
 	return STATUS_ERR;
 }
 
-static char *sidnames[] = {
+static const char *const sidnames[] = {
 	"undefined",
 	"kernel",
 	"security",