gstreamer/gst/cothreads/test-pth-pthreads2.c

#define __USE_GNU /* non-posix functions */
#include <pthread.h>
#undef __USE_GNU
#include <stdio.h>
#include "linuxthreads-internals.h"
#include "pth_p.h"

/* this function is only really necessary to get the main thread's
 * pthread_descr, as the other threads store the pthread_descr (actually the
 * first member of struct _pthread_descr_struct, which points to itself for the
 * default (non-indirected) case) at the top of the stack. */
static _pthread_descr linuxthreads_self() 
{
  pthread_mutexattr_t mutexattr;
  pthread_mutex_t mutex;
  _pthread_descr self;
  
  pthread_mutexattr_init (&mutexattr);
  pthread_mutexattr_setkind_np (&mutexattr, PTHREAD_MUTEX_ERRORCHECK_NP);
  pthread_mutex_init (&mutex, &mutexattr);

  pthread_mutex_lock (&mutex);
  self = mutex.__m_owner;
  pthread_mutex_unlock (&mutex);
  
  printf ("pthread_self: %d\n", pthread_self());
  printf ("descr: %p\n", self);
  printf ("*descr: %p\n", *(int*)self);
  
  return self;
}

pth_mctx_t main_context;
int threadnum = 0;

void cothread (void *unused)
{
  printf ("1.%d: current stack frame: %p\n", threadnum, CURRENT_STACK_FRAME);
  printf ("1.%d: sleeping 2s...\n", threadnum);
  sleep (2);
  printf ("1.%d: returning to cothread 1.0\n");
  pth_mctx_restore (&main_context);
}

void *pthread (void *unused) 
{
  char *sp = CURRENT_STACK_FRAME;
  char *cothread_stack;
  pth_mctx_t ctx;
  _pthread_descr descr;
  
  descr = linuxthreads_self();
  printf ("sp: %p\n", sp);
  printf ("STACK_SIZE: %p\n", STACK_SIZE);
  printf ("sp | STACK_SIZE: 0x%x\n", (int) sp | STACK_SIZE );
  printf ("(sp | (STACK_SIZE-1))+1 - 1K: 0x%x\n", ((((int)sp | (STACK_SIZE-1))+1) - 1024));
  printf ("*(sp | (STACK_SIZE-1))+1 - 1K: %p\n", *(int*)((((long int)sp | (STACK_SIZE-1))+1) - 1024));
  
  while (threadnum < 10) {
    if (posix_memalign (&cothread_stack, STACK_SIZE, STACK_SIZE)) {
      printf ("could not malloc a chunk of aligned memory\n");
      exit (-1);
    }
    
    printf ("1: setting *%p = %p\n", cothread_stack + STACK_SIZE - 1024, descr);
    memcpy(cothread_stack + STACK_SIZE - 1024, descr, 1024);
    
    pth_mctx_save (&main_context);
    printf ("1: spawning new thread, bottom = %p\n", cothread_stack);
    pth_mctx_set (&ctx, cothread, cothread_stack, cothread_stack + STACK_SIZE - 1024);
    printf ("1: switching to cothread %d...\n", ++threadnum);
    pth_mctx_switch (&main_context, &ctx);
  }
  
  printf ("1: back, returning...\n");
  
  return NULL;
}

int main (int argc, char *argv[]) 
{
  pthread_t tid;
  
  pthread_create (&tid, NULL, pthread, NULL);
  pthread_join (tid, NULL);
  
  linuxthreads_self();
  
  exit (0);
}