[crashtracker] API to enable/disable crash report collection

Author: danielsn

crashtracker-ffi/src/collector/mod.rs

@@ -14,6 +14,40 @@ use ddcommon_ffi::{wrap_with_void_ffi_result, Slice, VoidResult};
 use function_name::named;
 pub use spans::*;
 
+#[no_mangle]
+#[must_use]
+/// Disables the crashtracker.
+/// Note that this does not restore the old signal handlers, but rather turns crash-tracking into a
+/// no-op, and then chains the old handlers.  This means that handlers registered after the
+/// crashtracker will continue to work as expected.
+///
+/// # Preconditions
+///   None
+/// # Safety
+///   None
+/// # Atomicity
+///   This function is atomic and idempotent.  Calling it multiple times is allowed.
+pub unsafe extern "C" fn ddog_crasht_disable() -> VoidResult {
+    datadog_crashtracker::disable_crashtracker();
+    VoidResult::Ok(true)
+}
+
+#[no_mangle]
+#[must_use]
+/// Enables the crashtracker, if had been previously disabled.
+/// If crashtracking has not been initialized, this function will have no effect.
+///
+/// # Preconditions
+///   None
+/// # Safety
+///   None
+/// # Atomicity
+///   This function is atomic and idempotent.  Calling it multiple times is allowed.
+pub unsafe extern "C" fn ddog_crasht_enable() -> VoidResult {
+    datadog_crashtracker::enable_crashtracker();
+    VoidResult::Ok(true)
+}
+
 #[no_mangle]
 #[must_use]
 #[named]

crashtracker/src/collector/api.rs

@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 #![cfg(unix)]
 
-use super::receiver_manager::Receiver;
+use super::{crash_handler::enable_crashtracker, receiver_manager::Receiver};
 use crate::{
     clear_spans, clear_traces, collector::signal_handler_manager::register_crash_handlers,
     crash_info::Metadata, reset_counters, shared::configuration::CrashtrackerReceiverConfig,
@@ -68,6 +68,7 @@ pub fn init(
     update_config(config.clone())?;
     Receiver::update_stored_config(receiver_config);
     register_crash_handlers(&config)?;
+    enable_crashtracker();
     Ok(())
 }
 

crashtracker/src/collector/crash_handler.rs

@@ -15,7 +15,7 @@ use nix::sys::signal;
 use std::io::Write;
 use std::ptr;
 use std::sync::atomic::Ordering::SeqCst;
-use std::sync::atomic::{AtomicPtr, AtomicU64};
+use std::sync::atomic::{AtomicBool, AtomicPtr, AtomicU64};
 use std::time::Instant;
 
 // Note that this file makes use the following async-signal safe functions in a signal handler.
@@ -100,10 +100,44 @@ pub(crate) extern "C" fn handle_posix_sigaction(
     unsafe { chain_signal_handler(signum, sig_info, ucontext) };
 }
 
+static CRASHTRACKER_ENABLED: AtomicBool = AtomicBool::new(false);
+
+/// Disables the crashtracker.
+/// Note that this does not restore the old signal handlers, but rather turns crash-tracking into a
+/// no-op, and then chains the old handlers.  This means that handlers registered after the
+/// crashtracker will continue to work as expected.
+///
+/// # Preconditions
+///   None
+/// # Safety
+///   None
+/// # Atomicity
+///   This function is atomic and idempotent.  Calling it multiple times is allowed.
+pub fn disable_crashtracker() {
+    CRASHTRACKER_ENABLED.store(false, SeqCst);
+}
+
+/// Enables the crashtracker, if had been previously disabled.
+/// If crashtracking has not been initialized, this function will have no effect.
+///
+/// # Preconditions
+///   None
+/// # Safety
+///   None
+/// # Atomicity
+///   This function is atomic and idempotent.  Calling it multiple times is allowed.
+pub fn enable_crashtracker() {
+    CRASHTRACKER_ENABLED.store(true, SeqCst);
+}
+
 fn handle_posix_signal_impl(
     sig_info: *const siginfo_t,
     ucontext: *const ucontext_t,
 ) -> anyhow::Result<()> {
+    if !CRASHTRACKER_ENABLED.load(SeqCst) {
+        return Ok(());
+    }
+
     // If this is a SIGSEGV signal, it could be called due to a stack overflow. In that case, since
     // this signal allocates to the stack and cannot guarantee it is running without SA_NODEFER, it
     // is possible that we will re-emit the signal. Contemporary unices handle this just fine (no

crashtracker/src/collector/mod.rs

@@ -18,5 +18,7 @@ pub use additional_tags::{
 };
 pub use api::*;
 pub use counters::{begin_op, end_op, reset_counters, OpTypes};
-pub use crash_handler::{update_config, update_metadata};
+pub use crash_handler::{
+    disable_crashtracker, enable_crashtracker, update_config, update_metadata,
+};
 pub use spans::{clear_spans, clear_traces, insert_span, insert_trace, remove_span, remove_trace};

crashtracker/src/lib.rs

@@ -63,9 +63,9 @@ mod shared;
 #[cfg(all(unix, feature = "collector"))]
 pub use collector::{
     begin_op, clear_additional_tags, clear_spans, clear_traces, consume_and_emit_additional_tags,
-    default_signals, end_op, init, insert_additional_tag, insert_span, insert_trace, on_fork,
-    remove_additional_tag, remove_span, remove_trace, reset_counters, update_config,
-    update_metadata, OpTypes, DEFAULT_SYMBOLS,
+    default_signals, disable_crashtracker, enable_crashtracker, end_op, init,
+    insert_additional_tag, insert_span, insert_trace, on_fork, remove_additional_tag, remove_span,
+    remove_trace, reset_counters, update_config, update_metadata, OpTypes, DEFAULT_SYMBOLS,
 };
 
 #[cfg(all(windows, feature = "collector_windows"))]