msa/WriteTraceFileAction.cpp

   1 //
   2 //  WriteTraceFileAction.cpp
   3 //  system_cmds
   4 //
   5 //  Created by James McIlree on 4/29/14.
   6 //
   7 //
   8
   9 #include "global.h"
  10
  11 static bool shouldProcessEvents;
  12 static uint32_t sigintCount;
  13
  14 static bool start_tracing(Globals& globals)
  15 {
  16         if (!KDBG::reset()) return false;
  17         if (!KDBG::set_buffer_capacity(globals.trace_buffer_size())) return false;
  18         if (!KDBG::set_nowrap(false)) return false;
  19         if (!KDBG::initialize_buffers()) return false;
  20         if (!KDBG::set_enabled(KDEBUG_ENABLE_TRACE)) return false;
  21
  22         return true;
  23 }
  24
  25 static void end_tracing(void)
  26 {
  27         KDBG::reset();
  28 }
  29
  30 static void signal_handler_ctrl_C(int sig)
  31 {
  32         shouldProcessEvents = false;
  33         if (++sigintCount >= 5) {
  34                 // Not responding, nuke it from orbit.
  35                 exit(1);
  36         }
  37 }
  38
  39 void WriteTraceFileAction::execute(Globals& globals) {
  40         FileDescriptor fd(open(_path.c_str(), O_TRUNC|O_WRONLY|O_CREAT, 0777));
  41         if (!fd.is_open()) {
  42                 log_msg(ASL_LEVEL_ERR, "Unable to write to %s\n", _path.c_str());
  43                 return;
  44         }
  45
  46         shouldProcessEvents = true;
  47         sigintCount = 0;
  48
  49         VoucherContentSysctl contents(globals.should_trace_voucher_contents());
  50
  51         AbsTime t1 = AbsTime::now();
  52         if (start_tracing(globals)) {
  53                 // We cannot write the "maps" until after tracing has started.
  54                 if (KDBG::write_maps(fd)) {
  55                         signal(SIGINT, signal_handler_ctrl_C);
  56
  57                         while (shouldProcessEvents) {
  58                                 int events_written = KDBG::write_events(fd);
  59                                 AbsTime t2 = AbsTime::now();
  60                                 if (events_written != -1) {
  61                                         printf("wrote %d events - elapsed time = %.1f secs\n", events_written, (double)(t2 - t1).nano_time().value() / (double)NANOSECONDS_PER_SECOND);
  62                                 } else {
  63                                         log_msg(ASL_LEVEL_WARNING, "write events returned -1\n");
  64                                         break;
  65                                 }
  66                                 t1 = t2;
  67                         }
  68
  69                         signal(SIGINT, SIG_DFL);
  70                 }
  71         }
  72
  73         end_tracing();
  74 }