# EXC_BAD_ACCESS, Could not access memory zval array type - Thread: https://externals.io/message/60057 - Original archive: https://news-web.php.net/php.internals/60057 - Started by Yader Hernandez on 2012-04-17T06:12:41+00:00 - Messages: 3 - Reply by email to internals@lists.php.net - More for agents: search with https://externals.io/search.md?q={query} · JSON API at https://externals.io/api · documentation at https://externals.io/llms.txt --- ## #60057 — Yader Hernandez — 2012-04-17T06:12:41+00:00 URL: https://externals.io/message/60057#60057 Hello, I'm trying to create an ArrayList as an extension. I'm currently implementing ArrayList::contains(mixed $element) but I'm running into a blocking issue. It's currently causing a segfault when you call contains. I've tried to track down what I'm doing wrong, but I've had no luck with it. When running gdb this is what I get: Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: 13 at address: 0x00000000000000000x00000001005812ca in _zend_is_inconsistent /* {{{ proto public boolean ArrayList::contain(mixed $element[, boolean strict]) Returns true if this list contains the specified element. */ ZEND_METHOD(arraymap_class, contains) { zval *element; zend_bool strict = 0; /* strict comparison or not */ if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z|b", &element, &strict) == FAILURE) { RETURN_FALSE; } zval *this = getThis(); arraylist_object *intern; intern = (arraylist_object *) zend_object_store_get_object(this TSRMLS_CC); /* Don't use "ht" as a variable, it's already being used. All ZEND_METHOD have "ht" defined. */ HashTable *hash_table = Z_ARRVAL_P(intern->elements); HashPosition pos; zval **current; zval res; /* comparison result */ int (*is_equal_func)(zval *, zval *, zval * TSRMLS_DC) = is_equal_function; if (strict) { is_equal_func = is_identical_function; } zend_hash_internal_pointer_reset_ex(hash_table, &pos); while (zend_hash_get_current_data_ex(hash_table, (void **)¤t, &pos) == SUCCESS) { is_equal_func(&res, element, *current TSRMLS_CC); if (Z_LVAL(res)) { RETURN_TRUE; } zend_hash_move_forward_ex(hash_table, &pos); } RETURN_FALSE; } I can't seem to spot any errors with this implementation. The next thing I thought that could be wrong is how I'm creating elements pointer, but that seems correct too: static zend_object_value create_arraylist_object(zend_class_entry *ce TSRMLS_DC) /* {{{ */ { zend_object_value retval; arraylist_object *intern; intern = emalloc(sizeof(arraylist_object)); intern->size = 0; zend_object_std_init(&intern->std, ce TSRMLS_CC); ALLOC_INIT_ZVAL(intern->elements); array_init(intern->elements); intern->std.ce = ce; object_properties_init(&intern->std, ce); retval.handle = zend_objects_store_put(intern, NULL, destroy_arraylist_object, `NULL` TSRMLS_CC); retval.handlers = &arraylist_object_handlers; return retval; } /* }}} */ I'm not getting any compilation errors or any type of warnings. Everything seems to be glueing itself correctly. I'm hoping someone can see what I'm doing wrong so that I can move forward with this. thanks! --- ## #60059 — Laruence — 2012-04-17T07:06:32+00:00 URL: https://externals.io/message/60057#60059 · In reply to: #60057 Hi: you can core dump the backtrace, then exam the related hash table to find out what's going wrong there. and some maybe un-relevant issues: 1. plz put all var declarations at the begining of a block (C89) 2. do not use "this" keyword as variable name (it's C++ keyword) thanks On Tue, Apr 17, 2012 at 2:12 PM, Yader Hernandez wrote: > Hello, > > I'm trying to create an ArrayList as an extension. I'm currently > implementing ArrayList::contains(mixed $element) but I'm running into a > blocking issue. > > It's currently causing a segfault when you call contains. I've tried to > track down what I'm doing wrong, but I've had no luck with it. > > When running gdb this is what I get: > > Program received signal EXC_BAD_ACCESS, Could not access memory. > Reason: 13 at address: 0x00000000000000000x00000001005812ca in > _zend_is_inconsistent > > /* {{{ proto public boolean ArrayList::contain(mixed $element[, boolean > strict]) >  Returns true if this list contains the specified element. */ > ZEND_METHOD(arraymap_class, contains) { >  zval *element; >  zend_bool strict = 0;   /* strict comparison or not */ > >  if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z|b", &element, > &strict) == FAILURE) { >    RETURN_FALSE; >  } > >  zval *this = getThis(); >  arraylist_object *intern; > >  intern = (arraylist_object *) zend_object_store_get_object(this > TSRMLS_CC); > >  /* Don't use "ht" as a variable, it's already being used. All ZEND_METHOD > have "ht" defined. */ >  HashTable *hash_table = Z_ARRVAL_P(intern->elements); >  HashPosition pos; >  zval **current; >  zval res; /* comparison result */ > >  int (*is_equal_func)(zval *, zval *, zval * TSRMLS_DC) = > is_equal_function; > >  if (strict) { >    is_equal_func = is_identical_function; >  } > >  zend_hash_internal_pointer_reset_ex(hash_table, &pos); > >  while (zend_hash_get_current_data_ex(hash_table, (void **)¤t, &pos) > == SUCCESS) { >    is_equal_func(&res, element, *current TSRMLS_CC); > >    if (Z_LVAL(res)) { >      RETURN_TRUE; >    } > >    zend_hash_move_forward_ex(hash_table, &pos); >  } > >  RETURN_FALSE; > } > > I can't seem to spot any errors with this implementation. The next thing I > thought that could be wrong is how I'm creating elements pointer, but that > seems correct too: > > static zend_object_value create_arraylist_object(zend_class_entry *ce > TSRMLS_DC) /* {{{ */ > { >  zend_object_value retval; >  arraylist_object *intern; > >  intern = emalloc(sizeof(arraylist_object)); > >  intern->size = 0; > >  zend_object_std_init(&intern->std, ce TSRMLS_CC); > >  ALLOC_INIT_ZVAL(intern->elements); >  array_init(intern->elements); > >  intern->std.ce = ce; > >  object_properties_init(&intern->std, ce); > >  retval.handle = zend_objects_store_put(intern, NULL, > destroy_arraylist_object, `NULL` TSRMLS_CC); >  retval.handlers = &arraylist_object_handlers; > >  return retval; > } > /* }}} */ > > I'm not getting any compilation errors or any type of warnings. Everything > seems to be glueing itself correctly. > > I'm hoping someone can see what I'm doing wrong so that I can move forward > with this. > > thanks! -- Laruence  Xinchen Hui http://www.laruence.com/ --- ## #60085 — Yader Hernandez — 2012-04-17T16:12:38+00:00 URL: https://externals.io/message/60057#60085 · In reply to: #60059 > Hi: > > you can core dump the backtrace, then exam the related hash table to > find out what's going wrong there. So the problem doesn't seem to be with contains() at all. The problem is actually coming from another method I implemented called ArrayList::append(mixed $element). I figured it out by calling contains first and I noticed it didn't cause a segfault. appends() seems rather trivial but I guess I was wrong: /* {{{ proto public boolean ArrayList::append(mixed $element) Add an element to the end of the list */ ZEND_METHOD(arraymap_class, append) { zval *object = getThis(); zval *element; arraylist_object *intern; if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z", &element) == FAILURE) { RETURN_FALSE; } intern = (arraylist_object *) zend_object_store_get_object(object TSRMLS_CC); if (add_next_index_zval(intern->elements, element) == SUCCESS) { Z_ADDREF_P(element); /* increases ref count */ intern->size++; RETURN_TRUE; } RETURN_FALSE; } This method returns true, as expected. > and some maybe un-relevant issues: > 1. plz put all var declarations at the begining of a block (C89) > 2. do not use "this" keyword as variable name (it's C++ keyword) > fixed. > thanks > > On Tue, Apr 17, 2012 at 2:12 PM, Yader Hernandez > wrote: > > […] > ZEND_METHOD > > […] > &pos) > > […] > I > > […] > that > > […] > Everything > > […] > forward > > […] > > > > -- > Laruence Xinchen Hui > http://www.laruence.com/