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otel_observer.c
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otel_observer.c
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#include "php.h"
#include "otel_observer.h"
#include "zend_observer.h"
#include "zend_execute.h"
#include "zend_extensions.h"
#include "zend_exceptions.h"
#include "zend_attributes.h"
#include "php_opentelemetry.h"
static int op_array_extension = -1;
const char *withspan_fqn_lc = "opentelemetry\\api\\instrumentation\\withspan";
const char *spanattribute_fqn_lc =
"opentelemetry\\api\\instrumentation\\spanattribute";
static char *with_span_attribute_args_keys[] = {"name", "span_kind"};
typedef struct otel_observer {
zend_llist pre_hooks;
zend_llist post_hooks;
} otel_observer;
typedef struct otel_exception_state {
zend_object *exception;
zend_object *prev_exception;
const zend_op *opline_before_exception;
bool has_opline;
const zend_op *opline;
} otel_exception_state;
#define STACK_EXTENSION_LIMIT 16
typedef struct otel_arg_locator {
zend_execute_data *execute_data;
// Number of argument slots reserved in execute_data, any arguments beyond
// this limit will be stored after auxiliary slots
uint32_t reserved;
// Number of arguments provided at the call site. May exceed the number of
// arguments in the function definition
uint32_t provided;
// Number of slots between reserved and "extra" argument slots
uint32_t auxiliary_slots;
uint32_t extended_start;
uint32_t extended_max;
uint32_t extended_used;
zval extended_slots[STACK_EXTENSION_LIMIT];
} otel_arg_locator;
static inline void
func_get_this_or_called_scope(zval *zv, zend_execute_data *execute_data) {
if (execute_data->func->op_array.scope) {
if (execute_data->func->op_array.fn_flags & ZEND_ACC_STATIC) {
zend_class_entry *called_scope =
zend_get_called_scope(execute_data);
ZVAL_STR(zv, called_scope->name);
} else {
zend_object *this = zend_get_this_object(execute_data);
ZVAL_OBJ_COPY(zv, this);
}
} else {
ZVAL_NULL(zv);
}
}
static inline void func_get_function_name(zval *zv, zend_execute_data *ex) {
ZVAL_STR_COPY(zv, ex->func->op_array.function_name);
}
static zend_function *find_function(zend_class_entry *ce, zend_string *name) {
zend_function *func;
ZEND_HASH_FOREACH_PTR(&ce->function_table, func) {
if (zend_string_equals(func->common.function_name, name)) {
return func;
}
}
ZEND_HASH_FOREACH_END();
return NULL;
}
// find SpanAttribute attribute on a parameter, or on a parameter of
// an interface
static zend_attribute *find_spanattribute_attribute(zend_function *func,
uint32_t i) {
zend_attribute *attr = zend_get_parameter_attribute_str(
func->common.attributes, spanattribute_fqn_lc,
strlen(spanattribute_fqn_lc), i);
if (attr != NULL) {
return attr;
}
zend_class_entry *ce = func->common.scope;
if (ce && ce->num_interfaces > 0) {
zend_class_entry *interface_ce;
for (uint32_t i = 0; i < ce->num_interfaces; i++) {
interface_ce = ce->interfaces[i];
if (interface_ce != NULL) {
// does the interface have the function we are looking for?
zend_function *iface_func =
find_function(interface_ce, func->common.function_name);
if (iface_func != NULL) {
// method found, check positional arg for attribute
attr = zend_get_parameter_attribute_str(
iface_func->common.attributes, spanattribute_fqn_lc,
strlen(spanattribute_fqn_lc), i);
if (attr != NULL) {
return attr;
}
}
}
}
}
return NULL;
}
// find WithSpan in attributes, or in interface method attributes
static zend_attribute *find_withspan_attribute(zend_function *func) {
zend_attribute *attr;
attr = zend_get_attribute_str(func->common.attributes, withspan_fqn_lc,
strlen(withspan_fqn_lc));
if (attr != NULL) {
return attr;
}
zend_class_entry *ce = func->common.scope;
// if a method, check interfaces
if (ce && ce->num_interfaces > 0) {
zend_class_entry *interface_ce;
for (uint32_t i = 0; i < ce->num_interfaces; i++) {
interface_ce = ce->interfaces[i];
if (interface_ce != NULL) {
// does the interface have the function we are looking for?
zend_function *iface_func =
find_function(interface_ce, func->common.function_name);
if (iface_func != NULL) {
// Method found in the interface, now check for attributes
attr = zend_get_attribute_str(iface_func->common.attributes,
withspan_fqn_lc,
strlen(withspan_fqn_lc));
if (attr) {
return attr;
}
}
}
}
}
return NULL;
}
static bool func_has_withspan_attribute(zend_execute_data *ex) {
zend_attribute *attr = find_withspan_attribute(ex->func);
return attr != NULL;
}
/*
* OpenTelemetry attribute values may only be of limited types
*/
static bool is_valid_attribute_value(zval *val) {
switch (Z_TYPE_P(val)) {
case IS_STRING:
case IS_LONG:
case IS_DOUBLE:
case IS_TRUE:
case IS_FALSE:
case IS_ARRAY:
return true;
default:
return false;
}
}
// get function args. any args with the
// SpanAttributes attribute are added to the attributes HashTable
static void func_get_args(zval *zv, HashTable *attributes,
zend_execute_data *ex, bool check_for_attributes) {
zval *p, *q;
uint32_t i, first_extra_arg;
uint32_t arg_count = ZEND_CALL_NUM_ARGS(ex);
// @see
// https://github.com/php/php-src/blob/php-8.1.0/Zend/zend_builtin_functions.c#L235
if (arg_count) {
array_init_size(zv, arg_count);
if (ex->func->type == ZEND_INTERNAL_FUNCTION) {
first_extra_arg = arg_count;
} else {
first_extra_arg = ex->func->op_array.num_args;
}
zend_hash_real_init_packed(Z_ARRVAL_P(zv));
ZEND_HASH_FILL_PACKED(Z_ARRVAL_P(zv)) {
i = 0;
p = ZEND_CALL_ARG(ex, 1);
if (arg_count > first_extra_arg) {
while (i < first_extra_arg) {
q = p;
if (EXPECTED(Z_TYPE_INFO_P(q) != IS_UNDEF)) {
ZVAL_DEREF(q);
if (Z_OPT_REFCOUNTED_P(q)) {
Z_ADDREF_P(q);
}
ZEND_HASH_FILL_SET(q);
} else {
ZEND_HASH_FILL_SET_NULL();
}
ZEND_HASH_FILL_NEXT();
p++;
i++;
}
p = ZEND_CALL_VAR_NUM(ex, ex->func->op_array.last_var +
ex->func->op_array.T);
}
while (i < arg_count) {
if (check_for_attributes &&
ex->func->type != ZEND_INTERNAL_FUNCTION) {
zend_string *arg_name = ex->func->op_array.vars[i];
zend_attribute *attribute =
find_spanattribute_attribute(ex->func, i);
if (attribute != NULL && is_valid_attribute_value(p)) {
if (attribute->argc) {
zend_string *key = Z_STR(attribute->args[0].value);
zend_hash_del(attributes, key);
zend_hash_add(attributes, key, p);
} else {
zend_hash_del(attributes, arg_name);
zend_hash_add(attributes, arg_name, p);
}
}
}
q = p;
if (EXPECTED(Z_TYPE_INFO_P(q) != IS_UNDEF)) {
ZVAL_DEREF(q);
if (Z_OPT_REFCOUNTED_P(q)) {
Z_ADDREF_P(q);
}
ZEND_HASH_FILL_SET(q);
} else {
ZEND_HASH_FILL_SET_NULL();
}
ZEND_HASH_FILL_NEXT();
p++;
i++;
}
}
ZEND_HASH_FILL_END();
Z_ARRVAL_P(zv)->nNumOfElements = arg_count;
} else {
ZVAL_EMPTY_ARRAY(zv);
}
}
static uint32_t func_get_arg_index_by_name(zend_execute_data *execute_data,
zend_string *arg_name) {
// @see
// https://github.com/php/php-src/blob/php-8.1.0/Zend/zend_execute.c#L4515
zend_function *fbc = execute_data->func;
uint32_t num_args = fbc->common.num_args;
if (EXPECTED(fbc->type == ZEND_USER_FUNCTION) ||
EXPECTED(fbc->common.fn_flags & ZEND_ACC_USER_ARG_INFO)) {
for (uint32_t i = 0; i < num_args; i++) {
zend_arg_info *arg_info = &fbc->op_array.arg_info[i];
if (zend_string_equals(arg_name, arg_info->name)) {
return i;
}
}
} else {
for (uint32_t i = 0; i < num_args; i++) {
zend_internal_arg_info *arg_info =
&fbc->internal_function.arg_info[i];
size_t len = strlen(arg_info->name);
if (len == ZSTR_LEN(arg_name) &&
!memcmp(arg_info->name, ZSTR_VAL(arg_name), len)) {
return i;
}
}
}
return (uint32_t)-1;
}
static inline void func_get_retval(zval *zv, zval *retval) {
if (UNEXPECTED(!retval || Z_ISUNDEF_P(retval))) {
ZVAL_NULL(zv);
} else {
ZVAL_COPY(zv, retval);
}
}
static inline void func_get_exception(zval *zv) {
zend_object *exception = EG(exception);
if (exception && zend_is_unwind_exit(exception)) {
ZVAL_NULL(zv);
} else if (UNEXPECTED(exception)) {
ZVAL_OBJ_COPY(zv, exception);
} else {
ZVAL_NULL(zv);
}
}
static inline void func_get_declaring_scope(zval *zv, zend_execute_data *ex) {
if (ex->func->op_array.scope) {
ZVAL_STR_COPY(zv, ex->func->op_array.scope->name);
} else {
ZVAL_NULL(zv);
}
}
static inline void func_get_filename(zval *zv, zend_execute_data *ex) {
if (ex->func->type != ZEND_INTERNAL_FUNCTION) {
ZVAL_STR_COPY(zv, ex->func->op_array.filename);
} else {
ZVAL_NULL(zv);
}
}
static inline void func_get_lineno(zval *zv, zend_execute_data *ex) {
if (ex->func->type != ZEND_INTERNAL_FUNCTION) {
ZVAL_LONG(zv, ex->func->op_array.line_start);
} else {
ZVAL_NULL(zv);
}
}
static inline void func_get_attribute_args(zval *zv, HashTable *attributes,
zend_execute_data *ex) {
if (!OTEL_G(attr_hooks_enabled)) {
ZVAL_EMPTY_ARRAY(zv);
return;
}
zend_attribute *attr = find_withspan_attribute(ex->func);
if (attr == NULL || attr->argc == 0) {
ZVAL_EMPTY_ARRAY(zv);
return;
}
HashTable *ht;
ALLOC_HASHTABLE(ht);
zend_hash_init(ht, attr->argc, NULL, ZVAL_PTR_DTOR, 0);
zend_attribute_arg arg;
zend_string *key;
for (uint32_t i = 0; i < attr->argc; i++) {
arg = attr->args[i];
if (i == 2 ||
(arg.name && zend_string_equals_literal(arg.name, "attributes"))) {
// attributes, append to a separate HashTable
if (Z_TYPE(arg.value) == IS_ARRAY) {
zend_hash_clean(attributes); // should already be empty
HashTable *array_ht = Z_ARRVAL_P(&arg.value);
zend_hash_copy(attributes, array_ht, zval_add_ref);
}
} else {
if (arg.name != NULL) {
zend_hash_add(ht, arg.name, &arg.value);
} else {
key = zend_string_init(with_span_attribute_args_keys[i],
strlen(with_span_attribute_args_keys[i]),
0);
zend_hash_add(ht, key, &arg.value);
zend_string_release(key);
}
}
}
ZVAL_ARR(zv, ht);
}
/**
* Check if the object implements or extends the specified class
*/
bool is_object_compatible_with_type_hint(zval *object_zval,
zend_class_entry *type_hint) {
zend_class_entry *object_ce = Z_OBJCE_P(object_zval);
return instanceof_function(object_ce, type_hint);
}
/**
* Check if pre/post function callback's signature is compatible with
* the expected function signature.
* This is a runtime check, since some parameters are only known at runtime.
* Can be disabled via the opentelemetry.check_hook_functions ini value.
*/
static inline bool is_valid_signature(zend_fcall_info fci,
zend_fcall_info_cache fcc) {
if (OTEL_G(validate_hook_functions) == 0) {
return 1;
}
zend_function *func = fcc.function_handler;
zend_arg_info *arg_info;
zend_type *arg_type;
uint32_t type;
uint32_t type_mask;
for (uint32_t i = 0; i < func->common.num_args; i++) {
// get type mask of callback argument
arg_info = &func->common.arg_info[i];
arg_type = &arg_info->type;
type_mask = arg_type->type_mask;
// get actual value + type
zval param = fci.params[i];
type = Z_TYPE(fci.params[i]);
if (type_mask == IS_UNDEF) {
// no type mask -> ok
} else if (Z_TYPE(param) == IS_OBJECT) {
// object special-case handling (check for interfaces, subclasses)
zend_class_entry *ce = Z_OBJCE(param);
if (!is_object_compatible_with_type_hint(¶m, ce)) {
return false;
}
} else if ((type_mask & (1 << type)) == 0) {
// type is not compatible with mask
return false;
}
}
return true;
}
static void exception_isolation_start(otel_exception_state *save_state) {
save_state->exception = EG(exception);
save_state->prev_exception = EG(prev_exception);
save_state->opline_before_exception = EG(opline_before_exception);
EG(exception) = NULL;
EG(prev_exception) = NULL;
EG(opline_before_exception) = NULL;
// If the hook handler throws an exception, the execute_data of the outer
// frame may have its opline set to an exception handler too. This is done
// before the chance to clear the exception, so opline has to be restored
// to original value.
zend_execute_data *execute_data = EG(current_execute_data);
if (execute_data != NULL) {
save_state->has_opline = true;
save_state->opline = execute_data->opline;
} else {
save_state->has_opline = false;
save_state->opline = NULL;
}
}
static zend_object *exception_isolation_end(otel_exception_state *save_state) {
zend_object *suppressed = EG(exception);
// NULL this before call to zend_clear_exception, as it would try to jump
// to exception handler then.
EG(exception) = NULL;
// this clears prev_exception if it was set for any reason
zend_clear_exception();
EG(exception) = save_state->exception;
EG(prev_exception) = save_state->prev_exception;
EG(opline_before_exception) = save_state->opline_before_exception;
zend_execute_data *execute_data = EG(current_execute_data);
if (execute_data != NULL && save_state->has_opline) {
execute_data->opline = save_state->opline;
}
return suppressed;
}
static const char *zval_get_chars(zval *zv) {
if (zv != NULL && Z_TYPE_P(zv) == IS_STRING) {
return Z_STRVAL_P(zv);
}
return "null";
}
static void exception_isolation_handle_exception(zend_object *suppressed,
zval *class_name,
zval *function_name,
const char *type) {
if (suppressed == NULL) {
return;
}
zend_class_entry *exception_base = zend_get_exception_base(suppressed);
zval return_value;
zval *message =
zend_read_property_ex(exception_base, suppressed,
ZSTR_KNOWN(ZEND_STR_MESSAGE), 1, &return_value);
php_error_docref(NULL, E_CORE_WARNING,
"OpenTelemetry: %s threw exception,"
" class=%s function=%s message=%s",
type, zval_get_chars(class_name),
zval_get_chars(function_name), zval_get_chars(message));
if (message != NULL) {
ZVAL_DEREF(message);
}
OBJ_RELEASE(suppressed);
}
static void arg_locator_initialize(otel_arg_locator *arg_locator,
zend_execute_data *execute_data) {
arg_locator->execute_data = execute_data;
if (execute_data->func->type == ZEND_INTERNAL_FUNCTION) {
// For internal functions, rather than having reserved number of slots
// before auxiliary slots and extra ones after that, internal functions
// have all (and only) arguments provided by call site before auxiliary
// slots, and there is nothing after auxiliary slots.
arg_locator->reserved = ZEND_CALL_NUM_ARGS(execute_data);
} else {
arg_locator->reserved = execute_data->func->op_array.last_var;
}
arg_locator->provided = ZEND_CALL_NUM_ARGS(execute_data);
arg_locator->auxiliary_slots = execute_data->func->op_array.T;
arg_locator->extended_used = 0;
arg_locator->extended_start = arg_locator->provided > arg_locator->reserved
? arg_locator->provided
: arg_locator->reserved;
if (OTEL_G(allow_stack_extension)) {
arg_locator->extended_max = STACK_EXTENSION_LIMIT;
size_t slots_left_in_stack = EG(vm_stack_end) - EG(vm_stack_top);
if (slots_left_in_stack < arg_locator->extended_max) {
arg_locator->extended_max = slots_left_in_stack;
}
} else {
arg_locator->extended_max = 0;
}
}
static zval *arg_locator_get_slot(otel_arg_locator *arg_locator, uint32_t index,
const char **failure_reason) {
if (index < arg_locator->reserved) {
return ZEND_CALL_ARG(arg_locator->execute_data, index + 1);
} else if (index < arg_locator->provided) {
return ZEND_CALL_ARG(arg_locator->execute_data,
index + arg_locator->auxiliary_slots + 1);
}
uint32_t extended_index = index - arg_locator->extended_start;
if (extended_index < arg_locator->extended_max) {
uint32_t extended_index = index - arg_locator->extended_start;
if (extended_index >= arg_locator->extended_used) {
arg_locator->extended_used = extended_index + 1;
}
return &arg_locator->extended_slots[extended_index];
}
if (failure_reason != NULL) {
// Having a hardcoded upper limit allows performing stack
// extension as one step in the end, rather than moving slots around in
// the stack each time a new argument is discovered
if (extended_index >= STACK_EXTENSION_LIMIT) {
*failure_reason = "exceeds built-in stack extension limit";
} else if (!OTEL_G(allow_stack_extension)) {
*failure_reason = "stack extension must be enabled with "
"opentelemetry.allow_stack_extension option";
} else {
*failure_reason = "not enough room left in stack page";
}
}
return NULL;
}
static void arg_locator_store_extended(otel_arg_locator *arg_locator) {
if (arg_locator->extended_used == 0) {
return;
}
// This is safe because extended_max is adjusted to not exceed current stack
// page end
EG(vm_stack_top) += arg_locator->extended_used;
if (arg_locator->execute_data->func->type == ZEND_INTERNAL_FUNCTION) {
// For internal functions, the additional arguments need to go before
// the auxiliary slots, therefore the auxiliary slots need to be moved
// ahead
zval *target =
ZEND_CALL_ARG(arg_locator->execute_data, arg_locator->provided + 1);
zval *aux_target = target + arg_locator->extended_used;
memmove(aux_target, target,
sizeof(*aux_target) * arg_locator->auxiliary_slots);
memcpy(target, arg_locator->extended_slots,
sizeof(*target) * arg_locator->extended_used);
} else {
// For PHP functions, the additional arguments go to the end of the
// frame, so nothing else needs to be moved around
zval *target = ZEND_CALL_ARG(arg_locator->execute_data,
arg_locator->extended_start +
arg_locator->auxiliary_slots + 1);
memcpy(target, arg_locator->extended_slots,
sizeof(*target) * arg_locator->extended_used);
}
}
static void observer_begin(zend_execute_data *execute_data, zend_llist *hooks) {
if (!zend_llist_count(hooks)) {
return;
}
zval params[8];
uint32_t param_count = 8;
HashTable *attributes;
ALLOC_HASHTABLE(attributes);
zend_hash_init(attributes, 0, NULL, ZVAL_PTR_DTOR, 0);
bool check_for_attributes =
OTEL_G(attr_hooks_enabled) && func_has_withspan_attribute(execute_data);
func_get_this_or_called_scope(¶ms[0], execute_data);
func_get_attribute_args(¶ms[6], attributes, execute_data);
func_get_args(¶ms[1], attributes, execute_data, check_for_attributes);
func_get_declaring_scope(¶ms[2], execute_data);
func_get_function_name(¶ms[3], execute_data);
func_get_filename(¶ms[4], execute_data);
func_get_lineno(¶ms[5], execute_data);
ZVAL_ARR(¶ms[7], attributes);
for (zend_llist_element *element = hooks->head; element;
element = element->next) {
zend_fcall_info fci = empty_fcall_info;
zend_fcall_info_cache fcc = empty_fcall_info_cache;
if (UNEXPECTED(zend_fcall_info_init((zval *)element->data, 0, &fci,
&fcc, NULL, NULL) != SUCCESS)) {
php_error_docref(NULL, E_WARNING,
"Failed to initialize pre hook callable");
continue;
}
zval ret = {.u1.type_info = IS_UNDEF};
fci.param_count = param_count;
fci.params = params;
fci.named_params = NULL;
fci.retval = &ret;
if (!is_valid_signature(fci, fcc)) {
php_error_docref(NULL, E_CORE_WARNING,
"OpenTelemetry: pre hook invalid signature,"
" class=%s function=%s",
(Z_TYPE_P(¶ms[2]) == IS_NULL)
? "null"
: Z_STRVAL_P(¶ms[2]),
Z_STRVAL_P(¶ms[3]));
continue;
}
otel_exception_state save_state;
exception_isolation_start(&save_state);
if (zend_call_function(&fci, &fcc) == SUCCESS) {
if (Z_TYPE(ret) == IS_ARRAY &&
!zend_is_identical(&ret, ¶ms[1])) {
zend_ulong idx;
zend_string *str_idx;
zval *val;
bool invalid_arg_warned = false;
otel_arg_locator arg_locator;
arg_locator_initialize(&arg_locator, execute_data);
uint32_t args_initialized = arg_locator.provided;
ZEND_HASH_FOREACH_KEY_VAL(Z_ARR(ret), idx, str_idx, val) {
const char *failure_reason = "";
if (str_idx != NULL) {
idx = func_get_arg_index_by_name(execute_data, str_idx);
if (idx == (uint32_t)-1) {
php_error_docref(
NULL, E_CORE_WARNING,
"OpenTelemetry: pre hook unknown "
"named arg %s, class=%s function=%s",
ZSTR_VAL(str_idx), zval_get_chars(¶ms[2]),
zval_get_chars(¶ms[3]));
continue;
}
}
zval *target = arg_locator_get_slot(&arg_locator, idx,
&failure_reason);
if (target == NULL) {
if (invalid_arg_warned) {
continue;
}
php_error_docref(NULL, E_CORE_WARNING,
"OpenTelemetry: pre hook invalid "
"argument index " ZEND_ULONG_FMT
" - %s, class=%s function=%s",
idx, failure_reason,
zval_get_chars(¶ms[2]),
zval_get_chars(¶ms[3]));
invalid_arg_warned = true;
continue;
}
if (idx >= args_initialized) {
// This slot was not initialized, need to initialize
// all slots between current and the last initialized
// one
for (uint32_t i = args_initialized; i < idx; i++) {
ZVAL_UNDEF(
arg_locator_get_slot(&arg_locator, i, NULL));
ZEND_ADD_CALL_FLAG(execute_data,
ZEND_CALL_MAY_HAVE_UNDEF);
}
args_initialized = idx + 1;
} else {
// This slot was already initialized, need to
// decrement refcount before overwriting
zval_dtor(target);
}
if (idx >= arg_locator.reserved && Z_REFCOUNTED_P(val)) {
// If there are any "extra parameters" that are
// refcounted, then this flag must be set. While we
// cannot add any new extra parameter slots, this flag
// may not have been present because all the values
// were previously not refcounted
ZEND_ADD_CALL_FLAG(execute_data,
ZEND_CALL_FREE_EXTRA_ARGS);
}
ZVAL_COPY(target, val);
if (idx < arg_locator.provided &&
Z_TYPE(params[1]) == IS_ARRAY) {
// This index is present in the array provided to begin
// hook, update it in that array as well
Z_TRY_ADDREF_P(val);
zend_hash_index_update(Z_ARR(params[1]), idx, val);
}
}
ZEND_HASH_FOREACH_END();
arg_locator_store_extended(&arg_locator);
// Update provided argument count if begin hook added arguments
// that were not provided originally
if (args_initialized > arg_locator.provided) {
ZEND_CALL_NUM_ARGS(execute_data) = args_initialized;
}
}
}
zend_object *suppressed = exception_isolation_end(&save_state);
exception_isolation_handle_exception(suppressed, ¶ms[2], ¶ms[3],
"pre hook");
zval_dtor(&ret);
}
if (UNEXPECTED(ZEND_CALL_INFO(execute_data) & ZEND_CALL_MAY_HAVE_UNDEF)) {
zend_object *exception = EG(exception);
EG(exception) = (void *)(uintptr_t)-1;
if (zend_handle_undef_args(execute_data) == FAILURE) {
uint32_t arg_count = ZEND_CALL_NUM_ARGS(execute_data);
for (uint32_t i = 0; i < arg_count; i++) {
zval *arg = ZEND_CALL_VAR_NUM(execute_data, i);
if (!Z_ISUNDEF_P(arg)) {
continue;
}
ZVAL_NULL(arg);
}
}
EG(exception) = exception;
}
for (size_t i = 0; i < param_count; i++) {
zval_dtor(¶ms[i]);
}
}
static void observer_end(zend_execute_data *execute_data, zval *retval,
zend_llist *hooks) {
if (!zend_llist_count(hooks)) {
return;
}
zval params[8];
uint32_t param_count = 8;
func_get_this_or_called_scope(¶ms[0], execute_data);
func_get_args(¶ms[1], NULL, execute_data, false);
func_get_retval(¶ms[2], retval);
func_get_exception(¶ms[3]);
func_get_declaring_scope(¶ms[4], execute_data);
func_get_function_name(¶ms[5], execute_data);
func_get_filename(¶ms[6], execute_data);
func_get_lineno(¶ms[7], execute_data);
for (zend_llist_element *element = hooks->tail; element;
element = element->prev) {
zend_fcall_info fci = empty_fcall_info;
zend_fcall_info_cache fcc = empty_fcall_info_cache;
if (UNEXPECTED(zend_fcall_info_init((zval *)element->data, 0, &fci,
&fcc, NULL, NULL) != SUCCESS)) {
php_error_docref(NULL, E_WARNING,
"Failed to initialize post hook callable");
continue;
}
zval ret = {.u1.type_info = IS_UNDEF};
fci.param_count = param_count;
fci.params = params;
fci.named_params = NULL;
fci.retval = &ret;
if (!is_valid_signature(fci, fcc)) {
php_error_docref(NULL, E_CORE_WARNING,
"OpenTelemetry: post hook invalid signature, "
"class=%s function=%s",
(Z_TYPE_P(¶ms[4]) == IS_NULL)
? "null"
: Z_STRVAL_P(¶ms[4]),
Z_STRVAL_P(¶ms[5]));
continue;
}
otel_exception_state save_state;
exception_isolation_start(&save_state);
if (zend_call_function(&fci, &fcc) == SUCCESS) {
/* TODO rather than ignoring return value if post callback doesn't
have a return type-hint, could we check whether the types are
compatible and allow if they are? */
if (!Z_ISUNDEF(ret) &&
(fcc.function_handler->op_array.fn_flags &
ZEND_ACC_HAS_RETURN_TYPE) &&
!(ZEND_TYPE_PURE_MASK(
fcc.function_handler->common.arg_info[-1].type) &
MAY_BE_VOID)) {
if (execute_data->return_value) {
zval_ptr_dtor(execute_data->return_value);
ZVAL_COPY(execute_data->return_value, &ret);
zval_ptr_dtor(¶ms[2]);
ZVAL_COPY_VALUE(¶ms[2], &ret);
ZVAL_UNDEF(&ret);
}
}
}
zend_object *suppressed = exception_isolation_end(&save_state);
exception_isolation_handle_exception(suppressed, ¶ms[4], ¶ms[5],
"post hook");
zval_dtor(&ret);
}
for (size_t i = 0; i < param_count; i++) {
zval_dtor(¶ms[i]);
}
}
static void observer_begin_handler(zend_execute_data *execute_data) {
otel_observer *observer = ZEND_OP_ARRAY_EXTENSION(
&execute_data->func->op_array, op_array_extension);
if (!observer || !zend_llist_count(&observer->pre_hooks)) {
return;
}
observer_begin(execute_data, &observer->pre_hooks);
}
static void observer_end_handler(zend_execute_data *execute_data,
zval *retval) {
otel_observer *observer = ZEND_OP_ARRAY_EXTENSION(
&execute_data->func->op_array, op_array_extension);
if (!observer || !zend_llist_count(&observer->post_hooks)) {
return;
}
observer_end(execute_data, retval, &observer->post_hooks);
}
static void free_observer(otel_observer *observer) {
zend_llist_destroy(&observer->pre_hooks);
zend_llist_destroy(&observer->post_hooks);
efree(observer);
}
static void init_observer(otel_observer *observer) {
zend_llist_init(&observer->pre_hooks, sizeof(zval),
(llist_dtor_func_t)zval_ptr_dtor, 0);
zend_llist_init(&observer->post_hooks, sizeof(zval),
(llist_dtor_func_t)zval_ptr_dtor, 0);
}
static otel_observer *create_observer() {
otel_observer *observer = emalloc(sizeof(otel_observer));
init_observer(observer);
return observer;
}
static void copy_observer(otel_observer *source, otel_observer *destination) {
destination->pre_hooks = source->pre_hooks;
destination->post_hooks = source->post_hooks;
}
static bool find_observers(HashTable *ht, zend_string *n, zend_llist *pre_hooks,
zend_llist *post_hooks) {
otel_observer *observer = zend_hash_find_ptr_lc(ht, n);
if (observer) {
for (zend_llist_element *element = observer->pre_hooks.head; element;
element = element->next) {
zval_add_ref((zval *)&element->data);
zend_llist_add_element(pre_hooks, &element->data);
}
for (zend_llist_element *element = observer->post_hooks.head; element;
element = element->next) {
zval_add_ref((zval *)&element->data);
zend_llist_add_element(post_hooks, &element->data);
}
return true;
}
return false;
}
static void find_class_observers(HashTable *ht, HashTable *type_visited_lookup,
zend_class_entry *ce, zend_llist *pre_hooks,
zend_llist *post_hooks) {
for (; ce; ce = ce->parent) {
// Omit type if it was already visited
if (zend_hash_exists(type_visited_lookup, ce->name)) {
continue;
}
if (find_observers(ht, ce->name, pre_hooks, post_hooks)) {
zend_hash_add_empty_element(type_visited_lookup, ce->name);
}
for (uint32_t i = 0; i < ce->num_interfaces; i++) {
find_class_observers(ht, type_visited_lookup, ce->interfaces[i],
pre_hooks, post_hooks);
}
}
}
static void find_method_observers(HashTable *ht, zend_class_entry *ce,
zend_string *fn, zend_llist *pre_hooks,
zend_llist *post_hooks) {
// Below hashtable stores information
// whether type was already visited
// This information is used to prevent
// adding hooks more than once in the case
// of extensive class hierarchy
HashTable type_visited_lookup;
zend_hash_init(&type_visited_lookup, 8, NULL, NULL, 0);
HashTable *lookup = zend_hash_find_ptr_lc(ht, fn);
if (lookup) {
find_class_observers(lookup, &type_visited_lookup, ce, pre_hooks,
post_hooks);
}
zend_hash_destroy(&type_visited_lookup);
}
static zval create_attribute_observer_handler(char *fn) {
zval callable;
ZVAL_STRING(&callable, fn);
return callable;
}
static otel_observer *resolve_observer(zend_execute_data *execute_data) {
zend_function *fbc = execute_data->func;
if (!fbc->common.function_name) {
return NULL;
}
bool has_withspan_attribute = func_has_withspan_attribute(execute_data);
if (OTEL_G(attr_hooks_enabled) == false && has_withspan_attribute) {
php_error_docref(NULL, E_CORE_WARNING,
"OpenTelemetry: WithSpan attribute found but "
"attribute hooks disabled");
}
otel_observer observer_instance;
init_observer(&observer_instance);
if (fbc->op_array.scope) {
find_method_observers(OTEL_G(observer_class_lookup),
fbc->op_array.scope, fbc->common.function_name,
&observer_instance.pre_hooks,
&observer_instance.post_hooks);
} else {
find_observers(OTEL_G(observer_function_lookup),
fbc->common.function_name, &observer_instance.pre_hooks,
&observer_instance.post_hooks);
}
if (!zend_llist_count(&observer_instance.pre_hooks) &&
!zend_llist_count(&observer_instance.post_hooks)) {
if (OTEL_G(attr_hooks_enabled) && has_withspan_attribute) {