zend_constants.c

Go to the documentation of this file.

/*
   +----------------------------------------------------------------------+
   | Zend Engine                                                          |
   +----------------------------------------------------------------------+
   | Copyright (c) Zend Technologies Ltd. (http://www.zend.com)           |
   +----------------------------------------------------------------------+
   | This source file is subject to version 2.00 of the Zend license,     |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | http://www.zend.com/license/2_00.txt.                                |
   | If you did not receive a copy of the Zend license and are unable to  |
   | obtain it through the world-wide-web, please send a note to          |
   | license@zend.com so we can mail you a copy immediately.              |
   +----------------------------------------------------------------------+
   | Authors: Andi Gutmans <andi@php.net>                                 |
   |          Zeev Suraski <zeev@php.net>                                 |
   +----------------------------------------------------------------------+
*/
 
#include "zend.h"
#include "zend_constants.h"
#include "zend_exceptions.h"
#include "zend_execute.h"
#include "zend_variables.h"
#include "zend_operators.h"
#include "zend_globals.h"
#include "zend_API.h"
#include "zend_constants_arginfo.h"
 
/* Protection from recursive self-referencing class constants */
#define IS_CONSTANT_VISITED_MARK    0x80
 
#define IS_CONSTANT_VISITED(zv)     (Z_CONSTANT_FLAGS_P(zv) & IS_CONSTANT_VISITED_MARK)
#define MARK_CONSTANT_VISITED(zv)   Z_CONSTANT_FLAGS_P(zv) |= IS_CONSTANT_VISITED_MARK
#define RESET_CONSTANT_VISITED(zv)  Z_CONSTANT_FLAGS_P(zv) &= ~IS_CONSTANT_VISITED_MARK
 
/* Use for special null/true/false constants. */
static zend_constant *null_const, *true_const, *false_const;
 
void free_zend_constant(zval *zv)
{
    zend_constant *c = Z_PTR_P(zv);
 
    if (!(ZEND_CONSTANT_FLAGS(c) & CONST_PERSISTENT)) {
        zval_ptr_dtor_nogc(&c->value);
        if (c->name) {
            zend_string_release_ex(c->name, 0);
        }
        efree(c);
    } else {
        zval_internal_ptr_dtor(&c->value);
        if (c->name) {
            zend_string_release_ex(c->name, 1);
        }
        free(c);
    }
}
 
 
#ifdef ZTS
static void copy_zend_constant(zval *zv)
{
    zend_constant *c = Z_PTR_P(zv);
 
    ZEND_ASSERT(ZEND_CONSTANT_FLAGS(c) & CONST_PERSISTENT);
    Z_PTR_P(zv) = pemalloc(sizeof(zend_constant), 1);
    memcpy(Z_PTR_P(zv), c, sizeof(zend_constant));
 
    c = Z_PTR_P(zv);
    c->name = zend_string_copy(c->name);
    if (Z_TYPE(c->value) == IS_STRING) {
        Z_STR(c->value) = zend_string_dup(Z_STR(c->value), 1);
    }
}
 
 
void zend_copy_constants(HashTable *target, HashTable *source)
{
    zend_hash_copy(target, source, copy_zend_constant);
}
#endif
 
 
static int clean_module_constant(zval *el, void *arg)
{
    zend_constant *c = (zend_constant *)Z_PTR_P(el);
    int module_number = *(int *)arg;
 
    if (ZEND_CONSTANT_MODULE_NUMBER(c) == module_number) {
        return ZEND_HASH_APPLY_REMOVE;
    } else {
        return ZEND_HASH_APPLY_KEEP;
    }
}
 
 
void clean_module_constants(int module_number)
{
    zend_hash_apply_with_argument(EG(zend_constants), clean_module_constant, (void *) &module_number);
}
 
void zend_startup_constants(void)
{
    EG(zend_constants) = (HashTable *) malloc(sizeof(HashTable));
    zend_hash_init(EG(zend_constants), 128, NULL, ZEND_CONSTANT_DTOR, 1);
}
 
 
 
void zend_register_standard_constants(void)
{
    register_zend_constants_symbols(0);
 
    true_const = zend_hash_str_find_ptr(EG(zend_constants), "TRUE", sizeof("TRUE")-1);
    false_const = zend_hash_str_find_ptr(EG(zend_constants), "FALSE", sizeof("FALSE")-1);
    null_const = zend_hash_str_find_ptr(EG(zend_constants), "NULL", sizeof("NULL")-1);
}
 
ZEND_API void zend_register_null_constant(const char *name, size_t name_len, int flags, int module_number)
{
    zend_constant c;
 
    ZVAL_NULL(&c.value);
    ZEND_CONSTANT_SET_FLAGS(&c, flags, module_number);
    c.name = zend_string_init_interned(name, name_len, flags & CONST_PERSISTENT);
    zend_register_constant(&c);
}
 
ZEND_API void zend_register_bool_constant(const char *name, size_t name_len, bool bval, int flags, int module_number)
{
    zend_constant c;
 
    ZVAL_BOOL(&c.value, bval);
    ZEND_CONSTANT_SET_FLAGS(&c, flags, module_number);
    c.name = zend_string_init_interned(name, name_len, flags & CONST_PERSISTENT);
    zend_register_constant(&c);
}
 
ZEND_API void zend_register_long_constant(const char *name, size_t name_len, zend_long lval, int flags, int module_number)
{
    zend_constant c;
 
    ZVAL_LONG(&c.value, lval);
    ZEND_CONSTANT_SET_FLAGS(&c, flags, module_number);
    c.name = zend_string_init_interned(name, name_len, flags & CONST_PERSISTENT);
    zend_register_constant(&c);
}
 
 
ZEND_API void zend_register_double_constant(const char *name, size_t name_len, double dval, int flags, int module_number)
{
    zend_constant c;
 
    ZVAL_DOUBLE(&c.value, dval);
    ZEND_CONSTANT_SET_FLAGS(&c, flags, module_number);
    c.name = zend_string_init_interned(name, name_len, flags & CONST_PERSISTENT);
    zend_register_constant(&c);
}
 
 
ZEND_API void zend_register_stringl_constant(const char *name, size_t name_len, const char *strval, size_t strlen, int flags, int module_number)
{
    zend_constant c;
 
    ZVAL_STR(&c.value, zend_string_init_interned(strval, strlen, flags & CONST_PERSISTENT));
    ZEND_CONSTANT_SET_FLAGS(&c, flags, module_number);
    c.name = zend_string_init_interned(name, name_len, flags & CONST_PERSISTENT);
    zend_register_constant(&c);
}
 
 
ZEND_API void zend_register_string_constant(const char *name, size_t name_len, const char *strval, int flags, int module_number)
{
    zend_register_stringl_constant(name, name_len, strval, strlen(strval), flags, module_number);
}
 
static zend_constant *zend_get_halt_offset_constant(const char *name, size_t name_len)
{
    zend_constant *c;
    static const char haltoff[] = "__COMPILER_HALT_OFFSET__";
 
    if (!EG(current_execute_data)) {
        return NULL;
    } else if (name_len == sizeof("__COMPILER_HALT_OFFSET__")-1 &&
              !memcmp(name, "__COMPILER_HALT_OFFSET__", sizeof("__COMPILER_HALT_OFFSET__")-1)) {
        const char *cfilename;
        zend_string *haltname;
        size_t clen;
 
        cfilename = zend_get_executed_filename();
        clen = strlen(cfilename);
        /* check for __COMPILER_HALT_OFFSET__ */
        haltname = zend_mangle_property_name(haltoff,
            sizeof("__COMPILER_HALT_OFFSET__") - 1, cfilename, clen, 0);
        c = zend_hash_find_ptr(EG(zend_constants), haltname);
        zend_string_efree(haltname);
        return c;
    } else {
        return NULL;
    }
}
 
ZEND_API zend_constant *_zend_get_special_const(const char *name, size_t len) /* {{{ */
{
    if (len == 4) {
        if ((name[0] == 'n' || name[0] == 'N') &&
            (name[1] == 'u' || name[1] == 'U') &&
            (name[2] == 'l' || name[2] == 'L') &&
            (name[3] == 'l' || name[3] == 'L')
        ) {
            return null_const;
        }
        if ((name[0] == 't' || name[0] == 'T') &&
            (name[1] == 'r' || name[1] == 'R') &&
            (name[2] == 'u' || name[2] == 'U') &&
            (name[3] == 'e' || name[3] == 'E')
        ) {
            return true_const;
        }
    } else {
        if ((name[0] == 'f' || name[0] == 'F') &&
            (name[1] == 'a' || name[1] == 'A') &&
            (name[2] == 'l' || name[2] == 'L') &&
            (name[3] == 's' || name[3] == 'S') &&
            (name[4] == 'e' || name[4] == 'E')
        ) {
            return false_const;
        }
    }
    return NULL;
}
/* }}} */
 
ZEND_API bool zend_verify_const_access(zend_class_constant *c, zend_class_entry *scope) /* {{{ */
{
    if (ZEND_CLASS_CONST_FLAGS(c) & ZEND_ACC_PUBLIC) {
        return 1;
    } else if (ZEND_CLASS_CONST_FLAGS(c) & ZEND_ACC_PRIVATE) {
        return (c->ce == scope);
    } else {
        ZEND_ASSERT(ZEND_CLASS_CONST_FLAGS(c) & ZEND_ACC_PROTECTED);
        return zend_check_protected(c->ce, scope);
    }
}
/* }}} */
 
static zend_constant *zend_get_constant_str_impl(const char *name, size_t name_len)
{
    zend_constant *c = zend_hash_str_find_ptr(EG(zend_constants), name, name_len);
    if (c) {
        return c;
    }
 
    c = zend_get_halt_offset_constant(name, name_len);
    if (c) {
        return c;
    }
 
    return zend_get_special_const(name, name_len);
}
 
ZEND_API zval *zend_get_constant_str(const char *name, size_t name_len)
{
    zend_constant *c = zend_get_constant_str_impl(name, name_len);
    if (c) {
        return &c->value;
    }
    return NULL;
}
 
ZEND_API zend_constant *zend_get_constant_ptr(zend_string *name)
{
    zend_constant *c = zend_hash_find_ptr(EG(zend_constants), name);
    if (c) {
        return c;
    }
 
    c = zend_get_halt_offset_constant(ZSTR_VAL(name), ZSTR_LEN(name));
    if (c) {
        return c;
    }
 
    return zend_get_special_const(ZSTR_VAL(name), ZSTR_LEN(name));
}
 
ZEND_API zval *zend_get_constant(zend_string *name)
{
    zend_constant *c = zend_get_constant_ptr(name);
    if (c) {
        return &c->value;
    }
    return NULL;
}
 
ZEND_API zval *zend_get_class_constant_ex(zend_string *class_name, zend_string *constant_name, zend_class_entry *scope, uint32_t flags)
{
    zend_class_entry *ce = NULL;
    zend_class_constant *c = NULL;
    zval *ret_constant = NULL;
 
    if (ZSTR_HAS_CE_CACHE(class_name)) {
        ce = ZSTR_GET_CE_CACHE(class_name);
        if (!ce) {
            ce = zend_fetch_class(class_name, flags);
        }
    } else if (zend_string_equals_literal_ci(class_name, "self")) {
        if (UNEXPECTED(!scope)) {
            zend_throw_error(NULL, "Cannot access \"self\" when no class scope is active");
            goto failure;
        }
        ce = scope;
    } else if (zend_string_equals_literal_ci(class_name, "parent")) {
        if (UNEXPECTED(!scope)) {
            zend_throw_error(NULL, "Cannot access \"parent\" when no class scope is active");
            goto failure;
        } else if (UNEXPECTED(!scope->parent)) {
            zend_throw_error(NULL, "Cannot access \"parent\" when current class scope has no parent");
            goto failure;
        } else {
            ce = scope->parent;
        }
    } else if (zend_string_equals_ci(class_name, ZSTR_KNOWN(ZEND_STR_STATIC))) {
        ce = zend_get_called_scope(EG(current_execute_data));
        if (UNEXPECTED(!ce)) {
            zend_throw_error(NULL, "Cannot access \"static\" when no class scope is active");
            goto failure;
        }
    } else {
        ce = zend_fetch_class(class_name, flags);
    }
    if (ce) {
        c = zend_hash_find_ptr(CE_CONSTANTS_TABLE(ce), constant_name);
        if (c == NULL) {
            if ((flags & ZEND_FETCH_CLASS_SILENT) == 0) {
                zend_throw_error(NULL, "Undefined constant %s::%s", ZSTR_VAL(class_name), ZSTR_VAL(constant_name));
                goto failure;
            }
            ret_constant = NULL;
        } else {
            if (!zend_verify_const_access(c, scope)) {
                if ((flags & ZEND_FETCH_CLASS_SILENT) == 0) {
                    zend_throw_error(NULL, "Cannot access %s constant %s::%s", zend_visibility_string(ZEND_CLASS_CONST_FLAGS(c)), ZSTR_VAL(class_name), ZSTR_VAL(constant_name));
                }
                goto failure;
            }
 
            if (UNEXPECTED(ce->ce_flags & ZEND_ACC_TRAIT)) {
                if ((flags & ZEND_FETCH_CLASS_SILENT) == 0) {
                    zend_throw_error(NULL, "Cannot access trait constant %s::%s directly", ZSTR_VAL(class_name), ZSTR_VAL(constant_name));
                }
                goto failure;
            }
 
            if (UNEXPECTED(ZEND_CLASS_CONST_FLAGS(c) & ZEND_ACC_DEPRECATED)) {
                if ((flags & ZEND_FETCH_CLASS_SILENT) == 0) {
                    zend_deprecated_class_constant(c, constant_name);
                    if (EG(exception)) {
                        goto failure;
                    }
                }
            }
            ret_constant = &c->value;
        }
    }
 
    if (ret_constant && Z_TYPE_P(ret_constant) == IS_CONSTANT_AST) {
        zend_result ret;
 
        if (IS_CONSTANT_VISITED(ret_constant)) {
            zend_throw_error(NULL, "Cannot declare self-referencing constant %s::%s", ZSTR_VAL(class_name), ZSTR_VAL(constant_name));
            ret_constant = NULL;
            goto failure;
        }
 
        MARK_CONSTANT_VISITED(ret_constant);
        ret = zend_update_class_constant(c, constant_name, c->ce);
        RESET_CONSTANT_VISITED(ret_constant);
 
        if (UNEXPECTED(ret != SUCCESS)) {
            ret_constant = NULL;
            goto failure;
        }
    }
failure:
    return ret_constant;
}
 
ZEND_API zval *zend_get_constant_ex(zend_string *cname, zend_class_entry *scope, uint32_t flags)
{
    zend_constant *c;
    const char *colon;
    const char *name = ZSTR_VAL(cname);
    size_t name_len = ZSTR_LEN(cname);
 
    /* Skip leading \\ */
    if (name[0] == '\\') {
        name += 1;
        name_len -= 1;
        cname = NULL;
    }
 
    if ((colon = zend_memrchr(name, ':', name_len)) &&
        colon > name && (*(colon - 1) == ':')) {
        int class_name_len = colon - name - 1;
        size_t const_name_len = name_len - class_name_len - 2;
        zend_string *constant_name = zend_string_init(colon + 1, const_name_len, 0);
        zend_string *class_name = zend_string_init_interned(name, class_name_len, 0);
        zval *ret_constant = zend_get_class_constant_ex(class_name, constant_name, scope, flags);
 
        zend_string_release_ex(class_name, 0);
        zend_string_efree(constant_name);
        return ret_constant;
    }
 
    /* non-class constant */
    if ((colon = zend_memrchr(name, '\\', name_len)) != NULL) {
        /* compound constant name */
        int prefix_len = colon - name;
        size_t const_name_len = name_len - prefix_len - 1;
        const char *constant_name = colon + 1;
        char *lcname;
        size_t lcname_len;
        ALLOCA_FLAG(use_heap)
 
        /* Lowercase the namespace portion */
        lcname_len = prefix_len + 1 + const_name_len;
        lcname = do_alloca(lcname_len + 1, use_heap);
        zend_str_tolower_copy(lcname, name, prefix_len);
 
        lcname[prefix_len] = '\\';
        memcpy(lcname + prefix_len + 1, constant_name, const_name_len + 1);
 
        c = zend_hash_str_find_ptr(EG(zend_constants), lcname, lcname_len);
        free_alloca(lcname, use_heap);
 
        if (!c) {
            if (flags & IS_CONSTANT_UNQUALIFIED_IN_NAMESPACE) {
                /* name requires runtime resolution, need to check non-namespaced name */
                c = zend_get_constant_str_impl(constant_name, const_name_len);
            }
        }
    } else {
        if (cname) {
            c = zend_get_constant_ptr(cname);
        } else {
            c = zend_get_constant_str_impl(name, name_len);
        }
    }
 
    if (!c) {
        if (!(flags & ZEND_FETCH_CLASS_SILENT)) {
            zend_throw_error(NULL, "Undefined constant \"%s\"", name);
        }
        return NULL;
    }
 
    if (!(flags & ZEND_FETCH_CLASS_SILENT) && (ZEND_CONSTANT_FLAGS(c) & CONST_DEPRECATED)) {
        zend_error(E_DEPRECATED, "Constant %s is deprecated", name);
    }
    return &c->value;
}
 
static void* zend_hash_add_constant(HashTable *ht, zend_string *key, zend_constant *c)
{
    void *ret;
    zend_constant *copy = pemalloc(sizeof(zend_constant), ZEND_CONSTANT_FLAGS(c) & CONST_PERSISTENT);
 
    memcpy(copy, c, sizeof(zend_constant));
    ret = zend_hash_add_ptr(ht, key, copy);
    if (!ret) {
        pefree(copy, ZEND_CONSTANT_FLAGS(c) & CONST_PERSISTENT);
    }
    return ret;
}
 
ZEND_API zend_result zend_register_constant(zend_constant *c)
{
    zend_string *lowercase_name = NULL;
    zend_string *name;
    zend_result ret = SUCCESS;
    bool persistent = (ZEND_CONSTANT_FLAGS(c) & CONST_PERSISTENT) != 0;
 
#if 0
    printf("Registering constant for module %d\n", c->module_number);
#endif
 
    const char *slash = strrchr(ZSTR_VAL(c->name), '\\');
    if (slash) {
        lowercase_name = zend_string_init(ZSTR_VAL(c->name), ZSTR_LEN(c->name), persistent);
        zend_str_tolower(ZSTR_VAL(lowercase_name), slash - ZSTR_VAL(c->name));
        lowercase_name = zend_new_interned_string(lowercase_name);
        name = lowercase_name;
    } else {
        name = c->name;
    }
 
    /* Check if the user is trying to define any special constant */
    if (zend_string_equals_literal(name, "__COMPILER_HALT_OFFSET__")
        || (!persistent && zend_get_special_const(ZSTR_VAL(name), ZSTR_LEN(name)))
        || zend_hash_add_constant(EG(zend_constants), name, c) == NULL
    ) {
        zend_error(E_WARNING, "Constant %s already defined", ZSTR_VAL(name));
        zend_string_release(c->name);
        if (!persistent) {
            zval_ptr_dtor_nogc(&c->value);
        }
        ret = FAILURE;
    }
    if (lowercase_name) {
        zend_string_release(lowercase_name);
    }
    return ret;
}