Add plumbing for crash tracking / reporting work

* Add `--report-crash` option
* Install crash tracker upon profiler startup

Author: nsavoire

include/ddprof_cli.hpp

@@ -71,6 +71,8 @@ struct DDProfCLI {
   bool remote_symbolization{false};
   bool disable_symbolization{false};
   bool reorder_events{false}; // reorder events by timestamp
+  bool report_crash{false};
+  bool track_crashes{false};
   int maximum_pids{-1};
 
   std::string socket_path;

include/ddprof_context.hpp

@@ -36,6 +36,7 @@ struct DDProfContext {
     bool remote_symbolization{false};
     bool disable_symbolization{false};
     bool reorder_events{false}; // reorder events by timestamp
+    bool report_crash{false};
     int maximum_pids{0};
 
     cpu_set_t cpu_affinity{};

src/ddprof.cc

@@ -6,6 +6,7 @@
 #include "ddprof.hpp"
 
 #include "cap_display.hpp"
+#include "crash_tracker.hpp"
 #include "ddprof_cmdline.hpp"
 #include "ddprof_context.hpp"
 #include "ddprof_context_lib.hpp"
@@ -33,26 +34,6 @@
 
 namespace ddprof {
 namespace {
-/*****************************  SIGSEGV Handler *******************************/
-void sigsegv_handler(int sig, siginfo_t *si, void *uc) {
-  // TODO this really shouldn't call printf-family functions...
-  (void)uc;
-#ifdef __GLIBC__
-  constexpr size_t k_stacktrace_buffer_size = 4096;
-  static void *buf[k_stacktrace_buffer_size] = {};
-  size_t const sz = backtrace(buf, std::size(buf));
-#endif
-  (void)fprintf(
-      stderr, "ddprof[%d]: <%.*s> has encountered an error and will exit\n",
-      getpid(), static_cast<int>(str_version().size()), str_version().data());
-  if (sig == SIGSEGV) {
-    printf("[DDPROF] Fault address: %p\n", si->si_addr);
-  }
-#ifdef __GLIBC__
-  backtrace_symbols_fd(buf, sz, STDERR_FILENO);
-#endif
-  exit(-1);
-}
 
 void display_system_info() {
 
@@ -92,6 +73,25 @@ DDRes get_process_threads(pid_t pid, std::vector<pid_t> &threads) {
   return {};
 }
 
+void configure_crash_tracker(const DDProfContext &ctx) {
+  std::vector<std::string> args = {"--service", ctx.exp_input.service};
+  if (!ctx.exp_input.url.empty()) {
+    args.push_back("--url");
+    args.push_back(ctx.exp_input.url);
+  }
+  if (!ctx.exp_input.host.empty()) {
+    args.push_back("--host");
+    args.push_back(ctx.exp_input.host);
+  }
+  if (!ctx.exp_input.port.empty()) {
+    args.push_back("--port");
+    args.push_back(ctx.exp_input.port);
+  }
+
+  args.push_back("--report-crash");
+  install_crash_tracker("/proc/self/exe", args);
+}
+
 } // namespace
 
 DDRes ddprof_setup(DDProfContext &ctx) {
@@ -115,10 +115,7 @@ DDRes ddprof_setup(DDProfContext &ctx) {
 
     // Setup signal handler if defined
     if (ctx.params.fault_info) {
-      struct sigaction sigaction_handlers = {};
-      sigaction_handlers.sa_sigaction = sigsegv_handler;
-      sigaction_handlers.sa_flags = SA_SIGINFO;
-      sigaction(SIGSEGV, &(sigaction_handlers), nullptr);
+      configure_crash_tracker(ctx);
     }
 
     // Set the nice level, but only if it was overridden because 0 is valid

src/ddprof_cli.cc

@@ -398,6 +398,12 @@ int DDProfCLI::parse(int argc, const char *argv[]) {
                                  ->default_val(k_default_max_profiled_pids)
                                  ->envname("DD_PROFILING_MAXIMUM_PIDS")
                                  ->group(""));
+
+  extended_options.push_back(
+      app.add_flag("--report-crash", report_crash, "Report crash to Datadog")
+          ->default_val(false)
+          ->group(""));
+
   // Parse
   CLI11_PARSE(app, argc, argv);
 

src/ddprof_context_lib.cc

@@ -90,6 +90,7 @@ void copy_cli_values(const DDProfCLI &ddprof_cli, DDProfContext &ctx) {
   ctx.params.show_samples = ddprof_cli.show_samples;
   ctx.params.timeline = ddprof_cli.timeline;
   ctx.params.fault_info = ddprof_cli.fault_info;
+  ctx.params.report_crash = ddprof_cli.report_crash;
   ctx.params.remote_symbolization = ddprof_cli.remote_symbolization;
   ctx.params.disable_symbolization = ddprof_cli.disable_symbolization;
   ctx.params.reorder_events = ddprof_cli.reorder_events;

src/exe/main.cc

@@ -4,6 +4,7 @@
 // Datadog, Inc.
 
 #include "constants.hpp"
+#include "crash_reporter.hpp"
 #include "daemonize.hpp"
 #include "ddprof.hpp"
 #include "ddprof_cli.hpp"
@@ -409,6 +410,11 @@ int main(int argc, char *argv[]) {
 
     } // cli is destroyed here (prevents forks from having an instance of CLI
 
+    if (ctx->params.report_crash) {
+      report_crash(getppid(), ctx->params.pid, ctx->exp_input);
+      return 0;
+    }
+
     // Save switch_user since ctx will be destroyed after call to start_profiler
     std::string const switch_user = ctx->params.switch_user;