Fix windows

Signed-off-by: Bob Weinand <bob.weinand@datadoghq.com>

Author: bwoebi

ext/coms.c

@@ -771,10 +771,10 @@ static struct curl_slist *dd_agent_headers_alloc(void) {
     dd_append_header(&list, "Datadog-Meta-Lang-Interpreter", sapi_module.name, strlen(sapi_module.name));
     dd_append_header(&list, "Datadog-Meta-Lang-Version", php_version_rt.ptr, php_version_rt.len);
     dd_append_header(&list, "Datadog-Meta-Tracer-Version", ZEND_STRL(PHP_DDTRACE_VERSION));
-    if (!get_global_DD_APM_TRACING_ENABLED() || (ddtrace_sidecar && get_global_DD_TRACE_STATS_COMPUTATION_ENABLED())) {
+    if (!get_global_DD_APM_TRACING_ENABLED() || (ddtrace_sidecar_for_signal && get_global_DD_TRACE_STATS_COMPUTATION_ENABLED())) {
         dd_append_header(&list, "Datadog-Client-Computed-Stats", ZEND_STRL("true"));
     }
-    if (ddtrace_sidecar && get_global_DD_TRACE_STATS_COMPUTATION_ENABLED()) {
+    if (ddtrace_sidecar_for_signal && get_global_DD_TRACE_STATS_COMPUTATION_ENABLED()) {
         dd_append_header(&list, "Datadog-Client-Computed-Top-Level", ZEND_STRL("true"));
     }
 

ext/serializer.c

@@ -1362,7 +1362,7 @@ ddog_SpanBytes *ddtrace_serialize_span_to_rust_span(ddtrace_span_data *span, ddo
 
     // Trace-level filter: when stats computation is enabled, drop the span from the
     // entire pipeline (trace sending + stats) if its trace is filtered.
-    if (ddtrace_sidecar && get_DD_TRACE_STATS_COMPUTATION_ENABLED()) {
+    if (DDTRACE_G(sidecar) && get_DD_TRACE_STATS_COMPUTATION_ENABLED()) {
         if (DDTRACE_G(agent_info_reader)) {
             ddog_apply_agent_info_concentrator_config(DDTRACE_G(agent_info_reader));
         }
@@ -1534,7 +1534,7 @@ ddog_SpanBytes *ddtrace_serialize_span_to_rust_span(ddtrace_span_data *span, ddo
         ZEND_HASH_FOREACH_END();
 
 
-        if (!span_sampling_applied && ddtrace_sidecar && get_DD_TRACE_STATS_COMPUTATION_ENABLED() && ddog_is_agent_info_ready()) {
+        if (!span_sampling_applied && DDTRACE_G(sidecar) && get_DD_TRACE_STATS_COMPUTATION_ENABLED() && ddog_is_agent_info_ready()) {
             if (inferred_span) {
                 // Inferred span won't be serialized, so feed it to the concentrator here.
                 ddtrace_span_precomputed inferred_pre;
@@ -1779,7 +1779,7 @@ ddog_SpanBytes *ddtrace_serialize_span_to_rust_span(ddtrace_span_data *span, ddo
     zend_string_release(Z_STR(prop_root_service_as_string));
     zend_string_release(Z_STR(prop_service_as_string));
 
-    if (ddtrace_sidecar && get_DD_TRACE_STATS_COMPUTATION_ENABLED() && ddog_is_agent_info_ready()) {
+    if (DDTRACE_G(sidecar) && get_DD_TRACE_STATS_COMPUTATION_ENABLED() && ddog_is_agent_info_ready()) {
         ddtrace_feed_span_to_concentrator(span, &pre);
     }
 
@@ -1804,7 +1804,7 @@ ddog_SpanBytes *ddtrace_serialize_span_to_rust_span(ddtrace_span_data *span, ddo
         }
     }
 
-    if (ddtrace_sidecar && get_DD_TRACE_STATS_COMPUTATION_ENABLED() && !is_inferred_span) {
+    if (DDTRACE_G(sidecar) && get_DD_TRACE_STATS_COMPUTATION_ENABLED() && !is_inferred_span) {
         bool is_top_level_span = !span->parent;
         if (span->parent) {
             zval *parent_service = &SPANDATA(span->parent)->property_service;

ext/sidecar.c

@@ -1,6 +1,5 @@
 #include <php.h>
 #include <main/SAPI.h>
-#include <stdatomic.h>
 #include "ddtrace.h"
 #include "auto_flush.h"
 #include "compat_string.h"
@@ -31,9 +30,10 @@ struct ddog_InstanceId *ddtrace_sidecar_instance_id;
 static uint8_t dd_sidecar_formatted_session_id[36];
 
 // Best-effort pointer for the signal handler (SIGTERM/SIGINT). Set to the first
-// per-thread connection; never cleared until MSHUTDOWN. Signal context cannot
-// safely call TSRMLS_FETCH(), so this is the only option.
-_Atomic(ddog_SidecarTransport *) ddtrace_sidecar_for_signal = NULL;
+// per-thread connection; never cleared until MSHUTDOWN. Not atomic: concurrent
+// shutdown is already a best-effort race for signal handlers, so atomicity of
+// the pointer load alone would not prevent the underlying use-after-free.
+ddog_SidecarTransport *ddtrace_sidecar_for_signal = NULL;
 
 // Connection mode tracking
 dd_sidecar_active_mode_t ddtrace_sidecar_active_mode = DD_SIDECAR_CONNECTION_NONE;
@@ -408,9 +408,8 @@ void ddtrace_sidecar_setup(bool appsec_activation, bool appsec_config) {
     }
 
     // Record the first established connection for best-effort signal-handler use.
-    if (DDTRACE_G(sidecar)) {
-        ddog_SidecarTransport *expected = NULL;
-        atomic_compare_exchange_strong(&ddtrace_sidecar_for_signal, &expected, DDTRACE_G(sidecar));
+    if (DDTRACE_G(sidecar) && !ddtrace_sidecar_for_signal) {
+        ddtrace_sidecar_for_signal = DDTRACE_G(sidecar);
     }
 }
 
@@ -447,7 +446,7 @@ void ddtrace_sidecar_handle_fork(void) {
         ddog_sidecar_transport_drop(DDTRACE_G(sidecar));
         DDTRACE_G(sidecar) = NULL;
     }
-    atomic_store(&ddtrace_sidecar_for_signal, NULL);
+    ddtrace_sidecar_for_signal = NULL;
 
     if (ddtrace_sidecar_active_mode == DD_SIDECAR_CONNECTION_THREAD) {
         ddtrace_ffi_try("Failed clearing inherited listener state",
@@ -488,7 +487,7 @@ void ddtrace_sidecar_handle_fork(void) {
     }
 
     if (DDTRACE_G(sidecar)) {
-        atomic_store(&ddtrace_sidecar_for_signal, DDTRACE_G(sidecar));
+        ddtrace_sidecar_for_signal = DDTRACE_G(sidecar);
     }
 #endif
 }
@@ -500,9 +499,8 @@ void ddtrace_sidecar_ensure_active(void) {
         // First RINIT on this thread: the process-level setup already ran (endpoint is
         // set), so establish this thread's own connection now.
         DDTRACE_G(sidecar) = ddtrace_sidecar_connect(false);
-        if (DDTRACE_G(sidecar)) {
-            ddog_SidecarTransport *expected = NULL;
-            atomic_compare_exchange_strong(&ddtrace_sidecar_for_signal, &expected, DDTRACE_G(sidecar));
+        if (DDTRACE_G(sidecar) && !ddtrace_sidecar_for_signal) {
+            ddtrace_sidecar_for_signal = DDTRACE_G(sidecar);
         }
     }
 }
@@ -528,6 +526,8 @@ void ddtrace_sidecar_finalize(bool clear_id) {
 }
 
 void ddtrace_sidecar_shutdown(void) {
+    ddtrace_sidecar_for_signal = NULL;
+
     // In thread mode, drop the main thread's connection before shutting down the
     // listener to avoid deadlock.  GSHUTDOWN owns transport cleanup for all other
     // threads; the main thread's GSHUTDOWN runs after MSHUTDOWN on some SAPIs,
@@ -542,6 +542,8 @@ void ddtrace_sidecar_shutdown(void) {
         current_pid == ddtrace_sidecar_master_pid) {
 
         if (DDTRACE_G(sidecar)) {
+            ddtrace_sidecar_for_signal = NULL;
+
             ddog_sidecar_transport_drop(DDTRACE_G(sidecar));
             DDTRACE_G(sidecar) = NULL;
         }
@@ -556,8 +558,6 @@ void ddtrace_sidecar_shutdown(void) {
         ddtrace_sidecar_instance_id = NULL;
     }
 
-    atomic_store(&ddtrace_sidecar_for_signal, NULL);
-
     if (ddtrace_endpoint) {
         dd_free_endpoints();
     }
@@ -875,6 +875,10 @@ void ddtrace_sidecar_rshutdown(void) {
 
 void ddtrace_sidecar_gshutdown(void) {
     if (DDTRACE_G(sidecar)) {
+        if (DDTRACE_G(sidecar) == ddtrace_sidecar_for_signal) {
+            ddtrace_sidecar_for_signal = NULL;
+        }
+
         // Drain any accumulated background-sender metrics before the transport goes away.
         ddtrace_telemetry_flush_bgs_metrics_final();
         ddog_sidecar_transport_drop(DDTRACE_G(sidecar));

ext/sidecar.h

@@ -14,12 +14,12 @@ typedef enum {
     DD_SIDECAR_CONNECTION_THREAD = 2
 } dd_sidecar_active_mode_t;
 
-// ddtrace_sidecar lives in DDTRACE_G(sidecar) — one transport per thread.
 // ddtrace_sidecar_instance_id is a process global — one identity per PHP process.
 extern struct ddog_InstanceId *ddtrace_sidecar_instance_id;
 // Best-effort pointer used only by the signal handler (SIGTERM/SIGINT), which cannot call
 // TSRMLS_FETCH() safely.  Set to the first thread's connection; never cleared until MSHUTDOWN.
-extern _Atomic(ddog_SidecarTransport *) ddtrace_sidecar_for_signal;
+// Not atomic: concurrent shutdown is a pre-existing best-effort race for signal handlers.
+extern ddog_SidecarTransport *ddtrace_sidecar_for_signal;
 extern ddog_Endpoint *ddtrace_endpoint;
 extern dd_sidecar_active_mode_t ddtrace_sidecar_active_mode;
 extern int32_t ddtrace_sidecar_master_pid;

ext/signals.c

@@ -363,10 +363,7 @@ static int dd_call_prev_handler(bool flush) {
     }
 
     if (flush) {
-        // Load into a plain local: the function expects ddog_SidecarTransport **,
-        // but ddtrace_sidecar_for_signal is _Atomic so &it would be the wrong type.
-        ddog_SidecarTransport *sidecar = atomic_load(&ddtrace_sidecar_for_signal);
-        ddog_sidecar_flush_traces(&sidecar);
+        ddog_sidecar_flush_traces(&ddtrace_sidecar_for_signal);
     }
 
     if (prev_handler == SIG_DFL) {

ext/span_stats.c

@@ -397,7 +397,7 @@ void ddtrace_feed_span_to_concentrator(ddtrace_span_data *span, const ddtrace_sp
     ddtrace_concentrator_cb_data data = { .span = span, .pre = pre, .needs_ipc = false };
     ddog_span_concentrator_with(env_slice, version_slice, service_slice, ddtrace_span_concentrator_feed_cb, &data);
 
-    if (data.needs_ipc && ddtrace_sidecar) {
-        ddog_sidecar_add_php_span_to_concentrator(&ddtrace_sidecar, env_slice, version_slice, &data.ipc_stats);
+    if (data.needs_ipc && DDTRACE_G(sidecar)) {
+        ddog_sidecar_add_php_span_to_concentrator(&DDTRACE_G(sidecar), env_slice, version_slice, &data.ipc_stats);
     }
 }