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/* File descriptors.
Copyright (C) 1993,1994,1995,1996,1997,1998,1999,2000,2001,2002,2006,2007
Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _HURD_FD_H
#define _HURD_FD_H 1
#include <features.h>
#include <cthreads.h>
#include <hurd/hurd_types.h>
#include <hurd/port.h>
#include <sys/socket.h>
/* Structure representing a file descriptor. */
struct hurd_fd
struct hurd_port port; /* io server port. */
int flags; /* fcntl flags; locked by port.lock. */
/* Normal port to the ctty. When `port' is our ctty, this is a port to
the same io object but which never returns EBACKGROUND; when not,
this is nil. */
struct hurd_port ctty;
/* Current file descriptor table. */
extern int _hurd_dtablesize;
extern struct hurd_fd **_hurd_dtable;
extern struct mutex _hurd_dtable_lock; /* Locks those two variables. */
#include <hurd/signal.h>
#define _HURD_FD_H_EXTERN_INLINE __extern_inline
/* Returns the descriptor cell for FD. If FD is invalid or unused, return
NULL. The cell is unlocked; when ready to use it, lock it and check for
it being unused. */
_HURD_FD_H_EXTERN_INLINE struct hurd_fd *
_hurd_fd_get (int fd)
struct hurd_fd *descriptor;
__mutex_lock (&_hurd_dtable_lock);
if (fd < 0 || fd >= _hurd_dtablesize)
descriptor = NULL;
struct hurd_fd *cell = _hurd_dtable[fd];
if (cell == NULL)
/* No descriptor allocated at this index. */
descriptor = NULL;
__spin_lock (&cell->port.lock);
if (cell->port.port == MACH_PORT_NULL)
/* The descriptor at this index has no port in it.
This happens if it existed before but was closed. */
descriptor = NULL;
descriptor = cell;
__spin_unlock (&cell->port.lock);
__mutex_unlock (&_hurd_dtable_lock);
return descriptor;
/* Evaluate EXPR with the variable `descriptor' bound to a pointer to the
file descriptor structure for FD. */
#define HURD_FD_USE(fd, expr) \
({ struct hurd_fd *descriptor = _hurd_fd_get (fd); \
descriptor == NULL ? EBADF : (expr); })
/* Evaluate EXPR with the variable `port' bound to the port to FD, and
`ctty' bound to the ctty port. */
#define HURD_DPORT_USE(fd, expr) \
HURD_FD_USE ((fd), HURD_FD_PORT_USE (descriptor, (expr)))
/* Likewise, but FD is a pointer to the file descriptor structure. */
#define HURD_FD_PORT_USE(fd, expr) \
({ error_t __result; \
struct hurd_fd *const __d = (fd); \
struct hurd_userlink __ulink, __ctty_ulink; \
io_t port, ctty; \
void *crit = _hurd_critical_section_lock (); \
__spin_lock (&__d->port.lock); \
if (__d->port.port == MACH_PORT_NULL) \
{ \
__spin_unlock (&__d->port.lock); \
_hurd_critical_section_unlock (crit); \
__result = EBADF; \
} \
else \
{ \
ctty = _hurd_port_get (&__d->ctty, &__ctty_ulink); \
port = _hurd_port_locked_get (&__d->port, &__ulink); \
_hurd_critical_section_unlock (crit); \
__result = (expr); \
_hurd_port_free (&__d->port, &__ulink, port); \
if (ctty != MACH_PORT_NULL) \
_hurd_port_free (&__d->ctty, &__ctty_ulink, ctty); \
} \
__result; })
#include <errno.h>
/* Check if ERR should generate a signal.
Returns the signal to take, or zero if none. */
_hurd_fd_error_signal (error_t err)
switch (err)
/* The server has disappeared! */
return SIGLOST;
case EPIPE:
return SIGPIPE;
/* Having a default case avoids -Wenum-switch warnings. */
return 0;
/* Handle an error from an RPC on a file descriptor's port. You should
always use this function to handle errors from RPCs made on file
descriptor ports. Some errors are translated into signals. */
_hurd_fd_error (int fd, error_t err)
int signo = _hurd_fd_error_signal (err);
if (signo)
const struct hurd_signal_detail detail
= { code: fd, error: err, exc: 0 };
_hurd_raise_signal (NULL, signo, &detail);
return err;
/* Handle error code ERR from an RPC on file descriptor FD's port.
Set `errno' to the appropriate error code, and always return -1. */
__hurd_dfail (int fd, error_t err)
errno = _hurd_fd_error (fd, err);
return -1;
/* Likewise, but do not raise SIGPIPE on EPIPE if flags contain
__hurd_sockfail (int fd, int flags, error_t err)
if (!(flags & MSG_NOSIGNAL) || err != EPIPE)
err = _hurd_fd_error (fd, err);
errno = err;
return -1;
/* Set up *FD to have PORT its server port, doing appropriate ctty magic.
Does no locking or unlocking. */
extern void _hurd_port2fd (struct hurd_fd *fd, io_t port, int flags);
/* Allocate a new file descriptor and install PORT in it (doing any
appropriate ctty magic); consumes a user reference on PORT. FLAGS are
as for `open'; only O_IGNORE_CTTY is meaningful, but all are saved.
If the descriptor table is full, set errno, and return -1.
If DEALLOC is nonzero, deallocate PORT first. */
extern int _hurd_intern_fd (io_t port, int flags, int dealloc);
/* Allocate a new file descriptor in the table and return it, locked. The
new descriptor number will be no less than FIRST_FD. If the table is
full, set errno to EMFILE and return NULL. If FIRST_FD is negative or
bigger than the size of the table, set errno to EINVAL and return NULL. */
extern struct hurd_fd *_hurd_alloc_fd (int *fd_ptr, int first_fd);
/* Allocate a new file descriptor structure and initialize its port cells
with PORT and CTTY. (This does not affect the descriptor table.) */
extern struct hurd_fd *_hurd_new_fd (io_t port, io_t ctty);
/* Close a file descriptor, making it available for future reallocation. */
extern error_t _hurd_fd_close (struct hurd_fd *fd);
/* Read and write data from a file descriptor; just like `read' and `write'
if OFFSET is -1, or like `pread' and `pwrite' if OFFSET is not -1.
If successful, stores the amount actually read or written in *NBYTES. */
extern error_t _hurd_fd_read (struct hurd_fd *fd,
void *buf, size_t *nbytes, loff_t offset);
extern error_t _hurd_fd_write (struct hurd_fd *fd,
const void *buf, size_t *nbytes, loff_t offset);
/* Call *RPC on PORT and/or CTTY; if a call on CTTY returns EBACKGROUND,
generate SIGTTIN/SIGTTOU or EIO as appropriate. */
extern error_t _hurd_ctty_input (io_t port, io_t ctty, error_t (*rpc) (io_t));
extern error_t _hurd_ctty_output (io_t port, io_t ctty, error_t (*rpc) (io_t));
/* The guts of `select' and `poll'. Check the first NFDS descriptors
either in POLLFDS (if nonnull) or in each of READFDS, WRITEFDS,
EXCEPTFDS that is nonnull. If TIMEOUT is not NULL, time out after
waiting the interval specified therein. If SIGMASK is nonnull,
the set of blocked signals is temporarily set to that during this call.
Returns the number of ready descriptors, or -1 for errors. */
struct pollfd;
struct timespec;
extern int _hurd_select (int nfds, struct pollfd *pollfds,
fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
const struct timespec *timeout,
const sigset_t *sigmask);
/* Variant of file_name_lookup used in *at function implementations.
which will remove and add O_NOLINK from FLAGS respectively.
Other bits cause EINVAL. */
extern file_t __file_name_lookup_at (int fd, int at_flags,
const char *file_name,
int flags, mode_t mode);
/* Variant of file_name_split used in *at function implementations. */
extern file_t __file_name_split_at (int fd, const char *file_name,
char **name);
/* Variant of directory_name_split used in *at function implementations. */
extern file_t __directory_name_split_at (int fd, const char *directory_name,
char **name);
#endif /* hurd/fd.h */