C++ INLINE_SYSCALL函数代码示例

/* Create a device file named PATH relative to FD, with permission and
   special bits MODE and device number DEV (which can be constructed
   from major and minor device numbers with the `makedev' macro above).  */
int
__xmknodat (int vers, int fd, const char *file, mode_t mode, dev_t * dev)
{
  if (vers != _MKNOD_VER)
    {
      __set_errno (EINVAL);
      return -1;
    }

# ifndef __ASSUME_ATFCTS
  if (__have_atfcts >= 0)
# endif
    {
      int result;

      /* The FreeBSD mknod() system call cannot be used to create FIFOs; we
         must use the mkfifo() system call for this purpose.  */
      if (S_ISFIFO (mode))
	result = INLINE_SYSCALL (mkfifoat, 3, fd, file, mode);
      else
	result = INLINE_SYSCALL (mknodat, 4, fd, file, mode, *dev);

# ifndef __ASSUME_ATFCTS
      if (result == -1 && errno == ENOSYS)
	__have_atfcts = -1;
      else
# endif
	return result;
    }

#ifndef __ASSUME_ATFCTS
  if (fd != AT_FDCWD && file[0] != '/')
    {
      int mib[4];
      size_t kf_len = 0;
      char *kf_buf, *kf_bufp;
      size_t filelen;

      if (fd < 0)
	{
	  __set_errno (EBADF);
	  return -1;
	}

      filelen = strlen (file);
      if (__builtin_expect (filelen == 0, 0))
	{
	  __set_errno (ENOENT);
	  return -1;
	}

      mib[0] = CTL_KERN;
      mib[1] = KERN_PROC;
      mib[2] = KERN_PROC_FILEDESC;
      mib[3] = __getpid ();

      if (__sysctl (mib, 4, NULL, &kf_len, NULL, 0) != 0)
	{
	  __set_errno (ENOSYS);
	  return -1;
	}

      kf_buf = alloca (kf_len + filelen);
      if (__sysctl (mib, 4, kf_buf, &kf_len, NULL, 0) != 0)
	{
	  __set_errno (ENOSYS);
	  return -1;
	}

      kf_bufp = kf_buf;
      while (kf_bufp < kf_buf + kf_len)
	{
	  struct kinfo_file *kf = (struct kinfo_file *) (uintptr_t) kf_bufp;

	  if (kf->kf_fd == fd)
	    {
	      if (kf->kf_type != KF_TYPE_VNODE ||
		  kf->kf_vnode_type != KF_VTYPE_VDIR)
		{
		  __set_errno (ENOTDIR);
		  return -1;
		}

	      strcat (kf->kf_path, "/");
	      strcat (kf->kf_path, file);
	      file = kf->kf_path;
	      break;
	    }
	  kf_bufp += kf->kf_structsize;
	}

      if (kf_bufp >= kf_buf + kf_len)
	{
	  __set_errno (EBADF);
	  return -1;
	}
    }
//.........这里部分代码省略.........

int _DkMutexLockTimeout (struct mutex_handle * mut, int timeout)
{
    int i, c = 0;

    if (timeout == -1)
        return -_DkMutexLock(mut);

    struct atomic_int * m = &mut->value;

    /* Spin and try to take lock */
    for (i = 0 ; i < MUTEX_SPINLOCK_TIMES ; i++)
    {
        c = atomic_dec_and_test(m);
        if (c)
            goto success;
        cpu_relax();
    }

    /* The lock is now contended */

    int ret;

    if (timeout == 0) {
        ret = c ? 0 : -PAL_ERROR_TRYAGAIN;
        goto out;
    }

    while (!c) {
        int val = atomic_read(m);
        if (val == 1)
            goto again;

        struct timespec waittime;
        long sec = timeout / 1000000;
        long microsec = timeout - (sec * 1000000);
        waittime.tv_sec = sec;
        waittime.tv_nsec = microsec * 1000;

        ret = INLINE_SYSCALL(futex, 6, m, FUTEX_WAIT, val, &waittime, NULL, 0);

        if (IS_ERR(ret) &&
            ERRNO(ret) != EWOULDBLOCK &&
            ERRNO(ret) != EINTR) {
            ret = unix_to_pal_error(ERRNO(ret));
            goto out;
        }

#ifdef DEBUG_MUTEX
        if (IS_ERR(ret))
            printf("mutex held by thread %d\n", mut->owner);
#endif

again:
        /* Upon wakeup, we still need to check whether mutex is unlocked or
         * someone else took it.
         * If c==0 upon return from xchg (i.e., the older value of m==0), we
         * will exit the loop. Else, we sleep again (through a futex call).
         */
        c = atomic_dec_and_test(m);
    }

success:
#ifdef DEBUG_MUTEX
    mut->owner = INLINE_SYSCALL(gettid, 0);
#endif
    ret = 0;
out:
    return ret;
}

int
__real_chown (const char *file, uid_t owner, gid_t group)
{
# if __ASSUME_LCHOWN_SYSCALL == 0
  static int __libc_old_chown;
  int result;

  if (!__libc_old_chown)
    {
      int saved_errno = errno;
#  ifdef __NR_chown32
      if (__libc_missing_32bit_uids <= 0)
	{
	  int result;
	  int saved_errno = errno;

	  result = INLINE_SYSCALL (chown32, 3, CHECK_STRING (file), owner, group);
	  if (result == 0 || errno != ENOSYS)
	    return result;

	  __set_errno (saved_errno);
	  __libc_missing_32bit_uids = 1;
	}
#  endif /* __NR_chown32 */
      if (((owner + 1) > (uid_t) ((__kernel_uid_t) -1U))
	  || ((group + 1) > (gid_t) ((__kernel_gid_t) -1U)))
	{
	  __set_errno (EINVAL);
	  return -1;
	}

      result = INLINE_SYSCALL (chown, 3, CHECK_STRING (file), owner, group);

      if (result >= 0 || errno != ENOSYS)
	return result;

      __set_errno (saved_errno);
      __libc_old_chown = 1;
    }

  return __lchown (file, owner, group);
# elif __ASSUME_32BITUIDS
  /* This implies __ASSUME_LCHOWN_SYSCALL.  */
  return INLINE_SYSCALL (chown32, 3, CHECK_STRING (file), owner, group);
# else
  /* !__ASSUME_32BITUIDS && ASSUME_LCHOWN_SYSCALL  */
#  ifdef __NR_chown32
  if (__libc_missing_32bit_uids <= 0)
    {
      int result;
      int saved_errno = errno;

      result = INLINE_SYSCALL (chown32, 3, CHECK_STRING (file), owner, group);
      if (result == 0 || errno != ENOSYS)
	return result;

      __set_errno (saved_errno);
      __libc_missing_32bit_uids = 1;
    }
#  endif /* __NR_chown32 */
  if (((owner + 1) > (uid_t) ((__kernel_uid_t) -1U))
      || ((group + 1) > (gid_t) ((__kernel_gid_t) -1U)))
    {
      __set_errno (EINVAL);
      return -1;
    }

  return INLINE_SYSCALL (chown, 3, CHECK_STRING (file), owner, group);
# endif
}

/* Helper function to support starting threads for SIGEV_THREAD.  */
static void *
timer_helper_thread (void *arg)
{
  /* Wait for the SIGTIMER signal, allowing the setXid signal, and
     none else.  */
  sigset_t ss;
  sigemptyset (&ss);
  __sigaddset (&ss, SIGTIMER);

  /* Endless loop of waiting for signals.  The loop is only ended when
     the thread is canceled.  */
  while (1)
    {
      siginfo_t si;

      /* sigwaitinfo cannot be used here, since it deletes
	 SIGCANCEL == SIGTIMER from the set.  */

      int oldtype = LIBC_CANCEL_ASYNC ();

      /* XXX The size argument hopefully will have to be changed to the
	 real size of the user-level sigset_t.  */
      int result = INLINE_SYSCALL (rt_sigtimedwait, 4, &ss, &si, NULL,
				   _NSIG / 8);

      LIBC_CANCEL_RESET (oldtype);

      if (result > 0)
	{
	  if (si.si_code == SI_TIMER)
	    {
	      struct timer *tk = (struct timer *) si.si_ptr;

	      /* Check the timer is still used and will not go away
		 while we are reading the values here.  */
	      pthread_mutex_lock (&__active_timer_sigev_thread_lock);

	      struct timer *runp = __active_timer_sigev_thread;
	      while (runp != NULL)
		if (runp == tk)
		  break;
		else
		  runp = runp->next;

	      if (runp != NULL)
		{
		  struct thread_start_data *td = malloc (sizeof (*td));

		  /* There is not much we can do if the allocation fails.  */
		  if (td != NULL)
		    {
		      /* This is the signal we are waiting for.  */
		      td->thrfunc = tk->thrfunc;
		      td->sival = tk->sival;

		      pthread_t th;
		      (void) pthread_create (&th, &tk->attr,
					     timer_sigev_thread, td);
		    }
		}

	      pthread_mutex_unlock (&__active_timer_sigev_thread_lock);
	    }
	  else if (si.si_code == SI_TKILL)
	    /* The thread is canceled.  */
	    pthread_exit (NULL);
	}
    }
}

pid_t __libc_fork (void)
{
    return (pid_t) INLINE_SYSCALL (clone, 2, SIGCHLD, 0);
}

/* Change the owner and group of FILE.  */
int
__lchown (const char *file, uid_t owner, gid_t group)
{
  return INLINE_SYSCALL (fchownat, 5, AT_FDCWD, file, owner, group,
                         AT_SYMLINK_NOFOLLOW);
}

int _DkVirtualMemoryProtect (void * addr, int size, int prot)
{
    int ret = INLINE_SYSCALL(mprotect, 3, addr, size, HOST_PROT(prot));

    return IS_ERR(ret) ? unix_to_pal_error(ERRNO(ret)) : 0;
}

int
__new_semctl (int semid, int semnum, int cmd, ...)
{
  union semun arg;
  va_list ap;

  va_start (ap, cmd);

  /* Get the argument.  */
  arg = va_arg (ap, union semun);

  va_end (ap);

#if __ASSUME_32BITUIDS > 0
  return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
			 CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
#else
  switch (cmd) {
    case SEM_STAT:
    case IPC_STAT:
    case IPC_SET:
      break;
    default:
      return INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
			     CHECK_SEMCTL (&arg, semid, cmd));
  }

  {
    int result;
    struct __old_semid_ds old;
    struct semid_ds *buf;

#ifdef __NR_getuid32
    if (__libc_missing_32bit_uids <= 0)
      {
	if (__libc_missing_32bit_uids < 0)
	  {
	    int save_errno = errno;

	    /* Test presence of new IPC by testing for getuid32 syscall.  */
	    result = INLINE_SYSCALL (getuid32, 0);
	    if (result == -1 && errno == ENOSYS)
	      __libc_missing_32bit_uids = 1;
	    else
	      __libc_missing_32bit_uids = 0;
	    __set_errno(save_errno);
	  }
	if (__libc_missing_32bit_uids <= 0)
	  {
	    result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd | __IPC_64,
				     CHECK_SEMCTL (&arg, semid, cmd | __IPC_64));
	    return result;
	  }
      }
#endif

    buf = arg.buf;
    arg.__old_buf = &old;
    if (cmd == IPC_SET)
      {
	old.sem_perm.uid = buf->sem_perm.uid;
	old.sem_perm.gid = buf->sem_perm.gid;
	old.sem_perm.mode = buf->sem_perm.mode;
	if (old.sem_perm.uid != buf->sem_perm.uid ||
	    old.sem_perm.gid != buf->sem_perm.gid)
	  {
	    __set_errno (EINVAL);
	    return -1;
	  }
      }
    result = INLINE_SYSCALL (ipc, 5, IPCOP_semctl, semid, semnum, cmd,
			     CHECK_SEMCTL (&arg, semid, cmd));
    if (result != -1 && cmd != IPC_SET)
      {
	memset(buf, 0, sizeof(*buf));
	buf->sem_perm.__key = old.sem_perm.__key;
	buf->sem_perm.uid = old.sem_perm.uid;
	buf->sem_perm.gid = old.sem_perm.gid;
	buf->sem_perm.cuid = old.sem_perm.cuid;
	buf->sem_perm.cgid = old.sem_perm.cgid;
	buf->sem_perm.mode = old.sem_perm.mode;
	buf->sem_perm.__seq = old.sem_perm.__seq;
	buf->sem_otime = old.sem_otime;
	buf->sem_ctime = old.sem_ctime;
	buf->sem_nsems = old.sem_nsems;
      }
    return result;
  }
#endif
}

/* Create a one-way communication channel (__pipe).
   If successful, two file descriptors are stored in PIPEDES;
   bytes written on PIPEDES[1] can be read from PIPEDES[0].
   Returns 0 if successful, -1 if not.  */
int
__pipe (int __pipedes[2])
{
  return INLINE_SYSCALL (pipe2, 2, __pipedes, 0);
}

int
__shmctl (int shmid, int cmd, struct shmid_ds *buf)
{
  return INLINE_SYSCALL (shmctl, 3, shmid, cmd | __IPC_64, buf);
}

/* Call kernel with additional two arguments the syscall requires.  */
int
reboot (int howto)
{
  return INLINE_SYSCALL (reboot, 3, (int) 0xfee1dead, 672274793, howto);
}

/* Create a directory named PATH with protections MODE.  */
int
__mkdir (const char *path, mode_t mode)
{
  return INLINE_SYSCALL (mkdirat, 3, AT_FDCWD, path, mode);
}

/* Get information about the file NAME in BUF.  */
int
__xstat (int vers, const char *name, struct stat *buf)
{
  return INLINE_SYSCALL (stat, 2, name, buf);
}

int
__real_chown (const char *file, uid_t owner, gid_t group)
{
  return INLINE_SYSCALL (chown32, 3, file, owner, group);
}

/* Return information about the filesystem on which FD resides.  */
int
__fstatfs (int fd, struct statfs *buf)
{
  int rc = INLINE_SYSCALL (fstatfs64, 3, fd, sizeof (*buf), buf);
  return rc ?: statfs_overflow (buf);
}