/*

   +----------------------------------------------------------------------+

   | Zend Engine                                                          |

   +----------------------------------------------------------------------+

   | Copyright © Zend Technologies Ltd., a subsidiary company of          |

   |     Perforce Software, Inc., and Contributors.                       |

   +----------------------------------------------------------------------+

   | This source file is subject to the Modified BSD License that is      |

   | bundled with this package in the file LICENSE, and is available      |

   | through the World Wide Web at <https://www.php.net/license/>.        |

   |                                                                      |

   | SPDX-License-Identifier: BSD-3-Clause                                |

   +----------------------------------------------------------------------+

   | Authors: Andi Gutmans <andi@php.net>                                 |

   |          Zeev Suraski <zeev@php.net>                                 |

   +----------------------------------------------------------------------+

*/

#include "zend.h"

#include "zend_attributes.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);

    }

    if (c->filename) {

      zend_string_release_ex(c->filename, 0);

    }

    if (c->attributes) {

      zend_hash_release(c->attributes);

    }

    efree(c);

  } else {

    zval_internal_ptr_dtor(&c->value);

    if (c->name) {

      zend_string_release_ex(c->name, 1);

    }

    if (c->filename) {

      zend_string_release_ex(c->filename, 1);

    }

    if (c->attributes) {

      zend_hash_release(c->attributes);

    }

    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 (c->filename != NULL) {

    c->filename = zend_string_copy(c->filename);

  }

  if (c->attributes != NULL) {

    // Use the same attributes table

    GC_ADDREF(c->attributes);

  }

  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 zend_constant *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);

  return zend_register_constant(&c);

}

ZEND_API zend_constant *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);

  return zend_register_constant(&c);

}

ZEND_API zend_constant *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);

  return zend_register_constant(&c);

}

ZEND_API zend_constant *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);

  return zend_register_constant(&c);

}

ZEND_API zend_constant *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);

  return zend_register_constant(&c);

}

ZEND_API zend_constant *zend_register_string_constant(const char *name, size_t name_len, const char *strval, int flags, int module_number)

{

  return 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(const zend_class_constant *c, const 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, const zend_class_entry *scope, uint32_t flags)

{

  const 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_ci(class_name, ZSTR_KNOWN(ZEND_STR_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_ci(class_name, ZSTR_KNOWN(ZEND_STR_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)) {

        /** Prevent accessing trait constants directly on cases like \defined() or \constant(), etc. */

        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 && !CONST_IS_RECURSIVE(c)) {

          if (c->ce->type == ZEND_USER_CLASS) {

            /* Recursion protection only applied to user constants, GH-18463 */

            CONST_PROTECT_RECURSION(c);

          }

          zend_deprecated_class_constant(c, constant_name);

          if (c->ce->type == ZEND_USER_CLASS) {

            CONST_UNPROTECT_RECURSION(c);

          }

          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, const 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)) {

    if (!CONST_IS_RECURSIVE(c)) {

      CONST_PROTECT_RECURSION(c);

      zend_deprecated_constant(c, c->name);

      CONST_UNPROTECT_RECURSION(c);

      if (UNEXPECTED(EG(exception))) {

        return NULL;

      }

    }

  }

  return &c->value;

}

static void* zend_hash_add_constant(HashTable *ht, zend_string *key, const 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_constant *zend_register_constant(zend_constant *c)

{

  zend_string *lowercase_name = NULL;

  zend_string *name;

  zend_constant *ret = NULL;

  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;

  }

  c->filename = NULL;

  if (ZEND_CONSTANT_MODULE_NUMBER(c) == PHP_USER_CONSTANT) {

    zend_string *filename = zend_get_executed_filename_ex();

    if (filename) {

      c->filename = zend_string_copy(filename);

    }

  }

  c->attributes = NULL;

  if (zend_string_equals(name, ZSTR_CHAR('_')) || zend_string_ends_with_literal(name, "\\_")) {

    zend_error(E_DEPRECATED, "Calling a constant \"_\" is deprecated since 8.6");

  } else if (zend_string_equals_literal_ci(name, "let") || zend_string_ends_with_literal(name, "\\let")) {

    zend_error(E_DEPRECATED, "Calling a constant \"let\" is deprecated since 8.6");

  } else if (zend_string_equals_literal_ci(name, "is") || zend_string_ends_with_literal(name, "\\is")) {

    zend_error(E_DEPRECATED, "Calling a constant \"is\" is deprecated since 8.6");

  }

  /* 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)))

    || (ret = zend_hash_add_constant(EG(zend_constants), name, c)) == NULL

  ) {

    zend_error(E_WARNING, "Constant %s already defined, this will be an error in PHP 9", ZSTR_VAL(name));

    zend_string_release(c->name);

    if (c->filename) {

      zend_string_release(c->filename);

      c->filename = NULL;

    }

    if (!persistent) {

      zval_ptr_dtor_nogc(&c->value);

    }

  }

  if (lowercase_name) {

    zend_string_release(lowercase_name);

  }

  return ret;

}

void zend_constant_add_attributes(zend_constant *c, HashTable *attributes) {

  GC_TRY_ADDREF(attributes);

  c->attributes = attributes;

  zend_attribute *deprecated_attribute = zend_get_attribute_str(

    c->attributes,

    "deprecated",

    strlen("deprecated")

  );

  if (deprecated_attribute) {

    ZEND_CONSTANT_SET_FLAGS(

      c,

      ZEND_CONSTANT_FLAGS(c) | CONST_DEPRECATED,

      ZEND_CONSTANT_MODULE_NUMBER(c)

    );

  }

}