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glibc  2.9
Defines | Functions
fcntl.c File Reference
#include <errno.h>
#include <fcntl.h>
#include <hurd.h>
#include <hurd/fd.h>
#include <stdarg.h>
#include <sys/file.h>

Go to the source code of this file.

Defines

#define LOCKED(expr)

Functions

int __libc_fcntl (int fd, int cmd,...)

Define Documentation

#define LOCKED (   expr)
Value:
HURD_CRITICAL_BEGIN;                                          \
      __spin_lock (&d->port.lock);                                   \
      if (d->port.port == MACH_PORT_NULL)                            \
       result = __hurd_fail (EBADF);                                        \
      else                                                           \
       result = (expr);                                              \
      __spin_unlock (&d->port.lock);                                        \
      HURD_CRITICAL_END;

Function Documentation

int __libc_fcntl ( int  fd,
int  cmd,
  ... 
)

Definition at line 28 of file fcntl.c.

{
  va_list ap;
  struct hurd_fd *d;
  int result;

  d = _hurd_fd_get (fd);

  if (d == NULL)
    return __hurd_fail (EBADF);

  va_start (ap, cmd);

  switch (cmd)
    {
      error_t err;

    default:                /* Bad command.  */
      errno = EINVAL;
      result = -1;
      break;

      /* First the descriptor-based commands, which do no RPCs.  */

    case F_DUPFD:           /* Duplicate the file descriptor.  */
    case F_DUPFD_CLOEXEC:
      {
       struct hurd_fd *new;
       io_t port, ctty;
       struct hurd_userlink ulink, ctty_ulink;
       int flags;

       HURD_CRITICAL_BEGIN;

       /* Extract the ports and flags from the file descriptor.  */
       __spin_lock (&d->port.lock);
       flags = d->flags;
       ctty = _hurd_port_get (&d->ctty, &ctty_ulink);
       port = _hurd_port_locked_get (&d->port, &ulink); /* Unlocks D.  */

       if (cmd == F_DUPFD_CLOEXEC)
         flags |= FD_CLOEXEC;
       else
         /* Duplication clears the FD_CLOEXEC flag.  */
         flags &= ~FD_CLOEXEC;

       /* Get a new file descriptor.  The third argument to __fcntl is the
          minimum file descriptor number for it.  */
       new = _hurd_alloc_fd (&result, va_arg (ap, int));
       if (new == NULL)
         /* _hurd_alloc_fd has set errno.  */
         result = -1;
       else
         {
           /* Give the ports each a user ref for the new descriptor.  */
           __mach_port_mod_refs (__mach_task_self (), port,
                              MACH_PORT_RIGHT_SEND, 1);
           if (ctty != MACH_PORT_NULL)
             __mach_port_mod_refs (__mach_task_self (), ctty,
                                MACH_PORT_RIGHT_SEND, 1);

           /* Install the ports and flags in the new descriptor.  */
           if (ctty != MACH_PORT_NULL)
             _hurd_port_set (&new->ctty, ctty);
           new->flags = flags;
           _hurd_port_locked_set (&new->port, port); /* Unlocks NEW.  */
         }

       HURD_CRITICAL_END;

       _hurd_port_free (&d->port, &ulink, port);
       if (ctty != MACH_PORT_NULL)
         _hurd_port_free (&d->ctty, &ctty_ulink, port);

       break;
      }

      /* Set RESULT by evaluating EXPR with the descriptor locked.
        Check for an empty descriptor and return EBADF.  */
#define LOCKED(expr)                                                 \
      HURD_CRITICAL_BEGIN;                                           \
      __spin_lock (&d->port.lock);                                   \
      if (d->port.port == MACH_PORT_NULL)                            \
       result = __hurd_fail (EBADF);                                        \
      else                                                           \
       result = (expr);                                              \
      __spin_unlock (&d->port.lock);                                        \
      HURD_CRITICAL_END;

    case F_GETFD:           /* Get descriptor flags.  */
      LOCKED (d->flags);
      break;

    case F_SETFD:           /* Set descriptor flags.  */
      LOCKED ((d->flags = va_arg (ap, int), 0));
      break;


      /* Now the real io operations, done by RPCs to io servers.  */

    case F_GETLK:
    case F_SETLK:
    case F_SETLKW:
      {
       /* XXX
          We need new RPCs to support POSIX.1 fcntl file locking!!
          For the time being we support the whole-file case only,
          with all kinds of WRONG WRONG WRONG semantics,
          by using flock.  This is definitely the Wrong Thing,
          but it might be better than nothing (?).  */
       struct flock *fl = va_arg (ap, struct flock *);
       va_end (ap);
       switch (cmd)
         {
         case F_GETLK:
           errno = ENOSYS;
           return -1;
         case F_SETLK:
           cmd = LOCK_NB;
           break;
         default:
           cmd = 0;
           break;
         }
       switch (fl->l_type)
         {
         case F_RDLCK: cmd |= LOCK_SH; break;
         case F_WRLCK: cmd |= LOCK_EX; break;
         case F_UNLCK: cmd |= LOCK_UN; break;
         default:
           errno = EINVAL;
           return -1;
         }
       switch (fl->l_whence)
         {
         case SEEK_SET:
           if (fl->l_start == 0 && fl->l_len == 0) /* Whole file request.  */
             break;
           /* It seems to be common for applications to lock the first
              byte of the file when they are really doing whole-file locking.
              So, since it's so wrong already, might as well do that too.  */
           if (fl->l_start == 0 && fl->l_len == 1)
             break;
           /* FALLTHROUGH */
         case SEEK_CUR:
         case SEEK_END:
           errno = ENOTSUP;
           return -1;
         default:
           errno = EINVAL;
           return -1;
         }

       return __flock (fd, cmd);
      }

    case F_GETFL:           /* Get per-open flags.  */
      if (err = HURD_FD_PORT_USE (d, __io_get_openmodes (port, &result)))
       result = __hurd_dfail (fd, err);
      break;

    case F_SETFL:           /* Set per-open flags.  */
      err = HURD_FD_PORT_USE (d, __io_set_all_openmodes (port,
                                                  va_arg (ap, int)));
      result = err ? __hurd_dfail (fd, err) : 0;
      break;

    case F_GETOWN:          /* Get owner.  */
      if (err = HURD_FD_PORT_USE (d, __io_get_owner (port, &result)))
       result = __hurd_dfail (fd, err);
      break;

    case F_SETOWN:          /* Set owner.  */
      err = HURD_FD_PORT_USE (d, __io_mod_owner (port, va_arg (ap, pid_t)));
      result = err ? __hurd_dfail (fd, err) : 0;
      break;
    }

  va_end (ap);

  return result;
}

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