Handle fork in target application (#191)

* Always print PID in log messages

* omnitrace-dl updates

- omnitrace_preload does not call omnitrace_init or omnitrace_init_tooling
- omnitrace_preload will call omnitrace_set_mpi if OMNITRACE_USE_MPI
  or OMNITRACE_USE_MPIP in the env is true but not call it otherwise
  because doing so either overrides OMNITRACE_USE_PID (when true) or
  disable mpip from initialization (when false) and the MPI
  init can be caught later and override OMNITRACE_USE_PID

* config updates

- set_setting_value sets user update type
- remove volatile from get_settings_configured
- don't override settings::default_process_suffix
- don't kill process in omnitrace_exit_action
- set_state ignores updating state if >= State::Finalized

* Handle state > State::Finalized

* fork gotcha updates

- unsets LD_PRELOAD
- sets OMNITRACE_ROOT_PROCESS
- sets OMNITRACE_CHILD_PROCESS

* libomnitrace library.cpp updates

- basic_bundle for fini metrics
- handle finalization from child process

* sampling updates

- sampling::shutdown handles when child process

* Add example and test using fork

* Update run-ci script to support not submitting

* Tweak test envs

* Update build flags when codecov enabled

* remove unnecessary includes of sampling header

* Replace mpi copy/fini static lambda with free-funcs

* Update codecov job

* Fix OMPT segfaults after finalization

* Miscellaneous updates after rebase

* fixes for causal profiling

* revert some run-ci.sh changes

* Disable storing env in sampling::shutdown

* formatting fix

* Update timemory submodule

- fixed occasional synchronization issues with allocator offloading
- exclude protozero:: from internal samples

* improve root/child process detection

- avoid omnitrace_finalize in MPI when child process
- revert some testing tweaks

source/lib/omnitrace/library/components/fork_gotcha.cpp

@@ -20,10 +20,15 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-#include "library/components/fork_gotcha.hpp"
+#include "api.hpp"
+
 #include "core/config.hpp"
 #include "core/debug.hpp"
+#include "core/perfetto.hpp"
 #include "core/state.hpp"
+#include "library/components/fork_gotcha.hpp"
+#include "library/runtime.hpp"
+#include "library/sampling.hpp"
 
 #include <timemory/backends/process.hpp>
 #include <timemory/backends/threading.hpp>
@@ -46,8 +51,10 @@ void
 fork_gotcha::audit(const gotcha_data_t&, audit::incoming)
 {
     tim::set_env("OMNITRACE_PRELOAD", "0", 1);
-    OMNITRACE_VERBOSE(1, "fork() called on PID %i (rank: %i), TID %li\n",
-                      process::get_id(), dmp::rank(), threading::get_id());
+    tim::set_env("OMNITRACE_ROOT_PROCESS", process::get_id(), 0);
+    omnitrace_reset_preload_hidden();
+    OMNITRACE_BASIC_VERBOSE(0, "fork() called on PID %i (rank: %i), TID %li\n",
+                            process::get_id(), dmp::rank(), threading::get_id());
     OMNITRACE_BASIC_DEBUG(
         "Warning! Calling fork() within an OpenMPI application using libfabric "
         "may result is segmentation fault\n");
@@ -59,9 +66,31 @@ fork_gotcha::audit(const gotcha_data_t&, audit::outgoing, pid_t _pid)
 {
     if(_pid != 0)
     {
-        OMNITRACE_VERBOSE(1, "fork() called on PID %i created PID %i\n", getppid(), _pid);
+        OMNITRACE_BASIC_VERBOSE(0, "fork() called on PID %i created PID %i\n", getppid(),
+                                _pid);
+    }
+    else
+    {
+        OMNITRACE_REQUIRE(is_child_process())
+            << "Error! child process " << process::get_id()
+            << " believes it is the root process " << get_root_process_id() << "\n";
+        settings::enabled() = false;
+        settings::verbose() = -127;
+        settings::debug()   = false;
+        omnitrace::sampling::shutdown();
+        omnitrace::categories::shutdown();
+        omnitrace::get_perfetto_session().release();
+        set_thread_state(::omnitrace::ThreadState::Disabled);
+    }
+
+    if(!settings::use_output_suffix())
+    {
         settings::use_output_suffix()      = true;
         settings::default_process_suffix() = process::get_id();
+
+        OMNITRACE_BASIC_VERBOSE(
+            0, "call to fork() enables using an output suffix. PID %i will use %i\n",
+            process::get_id(), process::get_id());
     }
 }
 }  // namespace component