#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <inttypes.h>
#include <stdint.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <unistd.h>
#include <assert.h>

#include "Ecore.h"
#include "ecore_private.h"

/* make mono happy - this is evil though... */
#undef SIGPWR
/* valgrind in some versions/setups uses SIGRT's... hmmm */

typedef void (*Signal_Handler)(int sig, siginfo_t *si, void *foo);

static void _ecore_signal_callback_set(int            sig,
                                       Signal_Handler func);
static void _ecore_signal_callback_ignore(int        sig,
                                          siginfo_t *si,
                                          void      *foo);
static void _ecore_signal_callback_sigchld(int        sig,
                                           siginfo_t *si,
                                           void      *foo);
static void _ecore_signal_callback_sigusr1(int        sig,
                                           siginfo_t *si,
                                           void      *foo);
static void _ecore_signal_callback_sigusr2(int        sig,
                                           siginfo_t *si,
                                           void      *foo);
static void _ecore_signal_callback_sighup(int        sig,
                                          siginfo_t *si,
                                          void      *foo);
static void _ecore_signal_callback_sigquit(int        sig,
                                           siginfo_t *si,
                                           void      *foo);
static void _ecore_signal_callback_sigint(int        sig,
                                          siginfo_t *si,
                                          void      *foo);
static void _ecore_signal_callback_sigterm(int        sig,
                                           siginfo_t *si,
                                           void      *foo);
#ifdef SIGPWR
static void _ecore_signal_callback_sigpwr(int        sig,
                                          siginfo_t *si,
                                          void      *foo);
#endif

static Eina_Bool _ecore_signal_exe_exit_delay(void *data);

//#define MAXSIGQ 256 // 32k
#define MAXSIGQ 64 // 8k

static volatile sig_atomic_t sig_count = 0;
static volatile sig_atomic_t sigchld_count = 0;
static volatile sig_atomic_t sigusr1_count = 0;
static volatile sig_atomic_t sigusr2_count = 0;
static volatile sig_atomic_t sighup_count = 0;
static volatile sig_atomic_t sigquit_count = 0;
static volatile sig_atomic_t sigint_count = 0;
static volatile sig_atomic_t sigterm_count = 0;
#ifdef SIGPWR
static volatile sig_atomic_t sigpwr_count = 0;
#endif

static volatile siginfo_t sigchld_info[MAXSIGQ];
static volatile siginfo_t sigusr1_info[MAXSIGQ];
static volatile siginfo_t sigusr2_info[MAXSIGQ];
static volatile siginfo_t sighup_info[MAXSIGQ];
static volatile siginfo_t sigquit_info[MAXSIGQ];
static volatile siginfo_t sigint_info[MAXSIGQ];
static volatile siginfo_t sigterm_info[MAXSIGQ];
#ifdef SIGPWR
static volatile siginfo_t sigpwr_info[MAXSIGQ];
#endif

#if defined(SIG_ATOMIC_MAX)
# if SIG_ATOMIC_MAX == INT64_MAX
/* Basically FreeBSD on 64bits */
#  define PRIdSIGATOMIC PRId64
# elif SIG_ATOMIC_MAX == UINT64_MAX
#  define PRIdSIGATOMIC PRIu64
# elif SIG_ATOMIC_MAX == UINT32_MAX
#  define PRIdSIGATOMIC PRIu32
# else
/* everybody else seems to go for int */
#  define PRIdSIGATOMIC PRId32
# endif
#else
# define PRIdSIGATOMIC "d"
#endif

void
_ecore_signal_shutdown(void)
{
   _ecore_signal_callback_set(SIGPIPE, (Signal_Handler)SIG_DFL);
   _ecore_signal_callback_set(SIGALRM, (Signal_Handler)SIG_DFL);
   // XXX: consider using new clone4 features:
   // http://code.qt.io/cgit/qt/qtbase.git/tree/src/3rdparty/forkfd/forkfd.c
   // https://lkml.org/lkml/2015/3/12/1060
   // https://lkml.org/lkml/2015/3/12/1044
   _ecore_signal_callback_set(SIGCHLD, (Signal_Handler)SIG_DFL);
   _ecore_signal_callback_set(SIGUSR1, (Signal_Handler)SIG_DFL);
   _ecore_signal_callback_set(SIGUSR2, (Signal_Handler)SIG_DFL);
   _ecore_signal_callback_set(SIGHUP, (Signal_Handler)SIG_DFL);
   _ecore_signal_callback_set(SIGQUIT, (Signal_Handler)SIG_DFL);
   _ecore_signal_callback_set(SIGINT, (Signal_Handler)SIG_DFL);
   _ecore_signal_callback_set(SIGTERM, (Signal_Handler)SIG_DFL);
#ifdef SIGPWR
   _ecore_signal_callback_set(SIGPWR, (Signal_Handler)SIG_DFL);
   sigpwr_count = 0;
#endif
   sigchld_count = 0;
   sigusr1_count = 0;
   sigusr2_count = 0;
   sighup_count = 0;
   sigquit_count = 0;
   sigint_count = 0;
   sigterm_count = 0;
   sig_count = 0;
}

void
_ecore_signal_init(void)
{
   _ecore_signal_callback_set(SIGPIPE, _ecore_signal_callback_ignore);
   _ecore_signal_callback_set(SIGALRM, _ecore_signal_callback_ignore);
   _ecore_signal_callback_set(SIGCHLD, _ecore_signal_callback_sigchld);
   _ecore_signal_callback_set(SIGUSR1, _ecore_signal_callback_sigusr1);
   _ecore_signal_callback_set(SIGUSR2, _ecore_signal_callback_sigusr2);
   _ecore_signal_callback_set(SIGHUP, _ecore_signal_callback_sighup);
   _ecore_signal_callback_set(SIGQUIT, _ecore_signal_callback_sigquit);
   _ecore_signal_callback_set(SIGINT, _ecore_signal_callback_sigint);
   _ecore_signal_callback_set(SIGTERM, _ecore_signal_callback_sigterm);
#ifdef SIGPWR
   _ecore_signal_callback_set(SIGPWR, _ecore_signal_callback_sigpwr);
#endif
}

void
_ecore_signal_received_process(void)
{
   while (_ecore_signal_count_get()) _ecore_signal_call();
}

int
_ecore_signal_count_get(void)
{
   return sig_count;
}

static void
_ecore_signal_generic_free(void *data EINA_UNUSED,
                           void *event)
{
   free(event);
}

void
_ecore_signal_call(void)
{
   volatile sig_atomic_t n;
   sigset_t oldset, newset;
   int tot;

   if (sig_count == 0) return;
   eina_evlog("+signals", NULL, 0.0, NULL);
   sigemptyset(&newset);
   sigaddset(&newset, SIGPIPE);
   sigaddset(&newset, SIGALRM);
   sigaddset(&newset, SIGCHLD);
   sigaddset(&newset, SIGUSR1);
   sigaddset(&newset, SIGUSR2);
   sigaddset(&newset, SIGHUP);
   sigaddset(&newset, SIGQUIT);
   sigaddset(&newset, SIGINT);
   sigaddset(&newset, SIGTERM);
#ifdef SIGPWR
   sigaddset(&newset, SIGPWR);
#endif
   sigprocmask(SIG_BLOCK, &newset, &oldset);
   if (sigchld_count > MAXSIGQ)
     WRN("%"PRIdSIGATOMIC" SIGCHLD in queue. max queue size %i. losing "
         "siginfo for extra signals.", sigchld_count, MAXSIGQ);
   tot = sigchld_count + sigusr1_count + sigusr2_count +
     sighup_count + sigquit_count + sigint_count + sigterm_count
#ifdef SIGPWR
     + sigpwr_count
#endif
     ;

   if (sig_count != tot)
     {
        ERR("sig_count (%"PRIdSIGATOMIC") != actual totals (%i) ",
            sig_count, tot);
        sig_count = tot;
     }

   for (n = 0; n < sigchld_count; n++)
     {
        pid_t pid;
        int status;

        while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
          {
             Ecore_Exe_Event_Del *e;

             /* FIXME: If this process is set respawn, respawn with a suitable backoff
              * period for those that need too much respawning.
              */
             e = _ecore_exe_event_del_new();
             if (e)
               {
                  if (WIFEXITED(status))
                    {
                       e->exit_code = WEXITSTATUS(status);
                       e->exited = 1;
                    }
                  else if (WIFSIGNALED(status))
                    {
                       e->exit_signal = WTERMSIG(status);
                       e->signalled = 1;
                    }
                  e->pid = pid;
                  e->exe = _ecore_exe_find(pid);

                  if ((n < MAXSIGQ) && (sigchld_info[n].si_signo))
                    e->data = sigchld_info[n];  /* No need to clone this. */

                  if ((e->exe) && (ecore_exe_flags_get(e->exe) & (ECORE_EXE_PIPE_READ | ECORE_EXE_PIPE_ERROR)))
                    {
     /* We want to report the Last Words of the exe, so delay this event.
      * This is twice as relevant for stderr.
      * There are three possibilities here -
      *  1 There are no Last Words.
      *  2 There are Last Words, they are not ready to be read.
      *  3 There are Last Words, they are ready to be read.
      *
      * For 1 we don't want to delay, for 3 we want to delay.
      * 2 is the problem.  If we check for data now and there
      * is none, then there is no way to differentiate 1 and 2.
      * If we don't delay, we may loose data, but if we do delay,
      * there may not be data and the exit event never gets sent.
      *
      * Any way you look at it, there has to be some time passed
      * before the exit event gets sent.  So the strategy here is
      * to setup a timer event that will send the exit event after
      * an arbitrary, but brief, time.
      *
      * This is probably paranoid, for the less paraniod, we could
      * check to see for Last Words, and only delay if there are any.
      * This has it's own set of problems.
      */
                         Ecore_Timer *doomsday_clock;

                         doomsday_clock = _ecore_exe_doomsday_clock_get(e->exe);
                         IF_FN_DEL(ecore_timer_del, doomsday_clock);
                         doomsday_clock = ecore_timer_add
                             (0.1, _ecore_signal_exe_exit_delay, e);
                         _ecore_exe_doomsday_clock_set(e->exe, doomsday_clock);
                    }
                  else
                    {
                       _ecore_event_add(ECORE_EXE_EVENT_DEL, e,
                                        _ecore_exe_event_del_free, NULL);
                    }
               }
          }
        sig_count--;
     }
   sigchld_count = 0;

   if (sigusr1_count > MAXSIGQ)
     WRN("%"PRIdSIGATOMIC" SIGUSR1 in queue. max queue size %i. losing "
         "siginfo for extra signals.", sigusr1_count, MAXSIGQ);
   for (n = 0; n < sigusr1_count; n++)
     {
        Ecore_Event_Signal_User *e;

        e = _ecore_event_signal_user_new();
        if (e)
          {
             e->number = 1;

             if ((n < MAXSIGQ) && (sigusr1_info[n].si_signo))
               e->data = sigusr1_info[n];

             _ecore_event_add(ECORE_EVENT_SIGNAL_USER, e,
                              _ecore_signal_generic_free, NULL);
          }
        sig_count--;
     }
   sigusr1_count = 0;

   if (sigusr2_count > MAXSIGQ)
     WRN("%"PRIdSIGATOMIC" SIGUSR2 in queue. max queue size %i. losing "
         "siginfo for extra signals.", sigusr2_count, MAXSIGQ);
   for (n = 0; n < sigusr2_count; n++)
     {
        Ecore_Event_Signal_User *e;

        e = _ecore_event_signal_user_new();
        if (e)
          {
             e->number = 2;

             if ((n < MAXSIGQ) && (sigusr2_info[n].si_signo))
               e->data = sigusr2_info[n];

             _ecore_event_add(ECORE_EVENT_SIGNAL_USER, e,
                              _ecore_signal_generic_free, NULL);
          }
        sig_count--;
     }
   sigusr2_count = 0;

   if (sighup_count > MAXSIGQ)
     WRN("%"PRIdSIGATOMIC" SIGHUP in queue. max queue size %i. losing "
         "siginfo for extra signals.", sighup_count, MAXSIGQ);
   for (n = 0; n < sighup_count; n++)
     {
        Ecore_Event_Signal_Hup *e;

        e = _ecore_event_signal_hup_new();
        if (e)
          {
             if ((n < MAXSIGQ) && (sighup_info[n].si_signo))
               e->data = sighup_info[n];

             _ecore_event_add(ECORE_EVENT_SIGNAL_HUP, e,
                              _ecore_signal_generic_free, NULL);
          }
        sig_count--;
     }
   sighup_count = 0;

   if (sigquit_count > MAXSIGQ)
     WRN("%"PRIdSIGATOMIC" SIGQUIT in queue. max queue size %i. losing "
         "siginfo for extra signals.", sigquit_count, MAXSIGQ);
   for (n = 0; n < sigquit_count; n++)
     {
        Ecore_Event_Signal_Exit *e;

        e = _ecore_event_signal_exit_new();
        if (e)
          {
             e->quit = 1;

             if ((n < MAXSIGQ) && (sigquit_info[n].si_signo))
               e->data = sigquit_info[n];

             _ecore_event_add(ECORE_EVENT_SIGNAL_EXIT, e,
                              _ecore_signal_generic_free, NULL);
          }
        sig_count--;
     }
   sigquit_count = 0;

   if (sigint_count > MAXSIGQ)
     WRN("%"PRIdSIGATOMIC" SIGINT in queue. max queue size %i. losing "
         "siginfo for extra signals.", sigint_count, MAXSIGQ);
   for (n = 0; n < sigint_count; n++)
     {
        Ecore_Event_Signal_Exit *e;

        e = _ecore_event_signal_exit_new();
        if (e)
          {
             e->interrupt = 1;

             if ((n < MAXSIGQ) && (sigint_info[n].si_signo))
               e->data = sigint_info[n];

             _ecore_event_add(ECORE_EVENT_SIGNAL_EXIT, e,
                              _ecore_signal_generic_free, NULL);
          }
        sig_count--;
     }
   sigint_count = 0;

   if (sigterm_count > MAXSIGQ)
     WRN("%"PRIdSIGATOMIC" SIGTERM in queue. max queue size %i. losing "
         "siginfo for extra signals.", sigterm_count, MAXSIGQ);
   for (n = 0; n < sigterm_count; n++)
     {
        Ecore_Event_Signal_Exit *e;

        e = _ecore_event_signal_exit_new();
        if (e)
          {
             e->terminate = 1;

             if ((n < MAXSIGQ) && (sigterm_info[n].si_signo))
               e->data = sigterm_info[n];

             _ecore_event_add(ECORE_EVENT_SIGNAL_EXIT, e,
                              _ecore_signal_generic_free, NULL);
          }
        sig_count--;
     }
   sigterm_count = 0;

#ifdef SIGPWR
   if (sigpwr_count > MAXSIGQ)
     WRN("%"PRIdSIGATOMIC" SIGPWR in queue. max queue size %i. losing "
         "siginfo for extra signals.", sigpwr_count, MAXSIGQ);
   for (n = 0; n < sigpwr_count; n++)
     {
        Ecore_Event_Signal_Power *e;

        e = _ecore_event_signal_power_new();
        if (e)
          {
             if ((n < MAXSIGQ) && (sigpwr_info[n].si_signo))
               e->data = sigpwr_info[n];

             _ecore_event_add(ECORE_EVENT_SIGNAL_POWER, e,
                              _ecore_signal_generic_free, NULL);
          }
        sig_count--;
     }
   sigpwr_count = 0;
#endif
   sig_count = 0;
   
   sigprocmask(SIG_SETMASK, &oldset, NULL);
   eina_evlog("-signals", NULL, 0.0, NULL);
}

static void
_ecore_signal_callback_set(int            sig,
                           Signal_Handler func)
{
   struct sigaction sa;

   sa.sa_sigaction = func;
   sa.sa_flags = SA_RESTART | SA_SIGINFO;
   sigemptyset(&sa.sa_mask);
   sigaction(sig, &sa, NULL);
}

static void
_ecore_signal_callback_ignore(int        sig EINA_UNUSED,
                              siginfo_t *si EINA_UNUSED,
                              void      *foo EINA_UNUSED)
{
}

static void
_ecore_signal_callback_sigchld(int        sig EINA_UNUSED,
                               siginfo_t *si,
                               void      *foo EINA_UNUSED)
{
   volatile sig_atomic_t n;
   n = sigchld_count;
   if (n < MAXSIGQ)
     {
        if (si)
          sigchld_info[n] = *si;
        else
          sigchld_info[n].si_signo = 0;
     }

   sigchld_count++;
   sig_count++;
}

static void
_ecore_signal_callback_sigusr1(int        sig EINA_UNUSED,
                               siginfo_t *si,
                               void      *foo EINA_UNUSED)
{
   volatile sig_atomic_t n;
   n = sigusr1_count;
   if (n < MAXSIGQ)
     {
        if (si)
          sigusr1_info[n] = *si;
        else
          sigusr1_info[n].si_signo = 0;
     }
   sigusr1_count++;
   sig_count++;
}

static void
_ecore_signal_callback_sigusr2(int        sig EINA_UNUSED,
                               siginfo_t *si,
                               void      *foo EINA_UNUSED)
{
   volatile sig_atomic_t n;
   n = sigusr2_count;
   if (n < MAXSIGQ)
     {
        if (si)
          sigusr2_info[n] = *si;
        else
          sigusr2_info[n].si_signo = 0;
     }
   sigusr2_count++;
   sig_count++;
}

static void
_ecore_signal_callback_sighup(int        sig EINA_UNUSED,
                              siginfo_t *si,
                              void      *foo EINA_UNUSED)
{
   volatile sig_atomic_t n;
   n = sighup_count;
   if (n < MAXSIGQ)
     {
        if (si)
          sighup_info[n] = *si;
        else
          sighup_info[n].si_signo = 0;
     }
   sighup_count++;
   sig_count++;
}

static void
_ecore_signal_callback_sigquit(int        sig EINA_UNUSED,
                               siginfo_t *si,
                               void      *foo EINA_UNUSED)
{
   volatile sig_atomic_t n;
   n = sigquit_count;
   if (n < MAXSIGQ)
     {
        if (si)
          sigquit_info[n] = *si;
        else
          sigquit_info[n].si_signo = 0;
     }
   sigquit_count++;
   sig_count++;
}

static void
_ecore_signal_callback_sigint(int        sig EINA_UNUSED,
                              siginfo_t *si,
                              void      *foo EINA_UNUSED)
{
   volatile sig_atomic_t n;
   n = sigint_count;
   if (n < MAXSIGQ)
     {
        if (si)
          sigint_info[n] = *si;
        else
          sigint_info[n].si_signo = 0;
     }
   sigint_count++;
   sig_count++;
}

static void
_ecore_signal_callback_sigterm(int        sig EINA_UNUSED,
                               siginfo_t *si,
                               void      *foo EINA_UNUSED)
{
   volatile sig_atomic_t n;
   n = sigterm_count;
   if (n < MAXSIGQ)
     {
        if (si)
          sigterm_info[n] = *si;
        else
          sigterm_info[n].si_signo = 0;
     }
   sigterm_count++;
   sig_count++;
}

#ifdef SIGPWR
static void
_ecore_signal_callback_sigpwr(int        sig EINA_UNUSED,
                              siginfo_t *si,
                              void      *foo EINA_UNUSED)
{
   volatile sig_atomic_t n;
   n = sigpwr_count;
   if (n < MAXSIGQ)
     {
        if (si)
          sigpwr_info[n] = *si;
        else
          sigpwr_info[n].si_signo = 0;
     }
   sigpwr_count++;
   sig_count++;
}

#endif

static Eina_Bool
_ecore_signal_exe_exit_delay(void *data)
{
   Ecore_Exe_Event_Del *e;

   e = data;
   if (e)
     {
        _ecore_exe_doomsday_clock_set(e->exe, NULL);
        _ecore_event_add(ECORE_EXE_EVENT_DEL, e,
                         _ecore_exe_event_del_free, NULL);
     }
   return ECORE_CALLBACK_CANCEL;
}