136 lines
3.8 KiB
C
136 lines
3.8 KiB
C
/* Copyright (C) 1991, 92, 93, 94, 95, 97 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <errno.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <hurd.h>
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#include <hurd/fd.h>
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/* Duplicate FD to FD2, closing the old FD2 and making FD2 be
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open on the same file as FD is. Return FD2 or -1. */
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int
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__dup2 (fd, fd2)
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int fd;
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int fd2;
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{
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struct hurd_fd *d;
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/* Extract the ports and flags from FD. */
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d = _hurd_fd_get (fd);
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if (d == NULL)
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{
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errno = EBADF;
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return -1;
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}
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HURD_CRITICAL_BEGIN;
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__spin_lock (&d->port.lock);
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if (d->port.port == MACH_PORT_NULL)
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{
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__spin_unlock (&d->port.lock);
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errno = EBADF;
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fd2 = -1;
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}
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else if (fd2 == fd)
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/* FD is valid and FD2 is already the same; just return it. */
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__spin_unlock (&d->port.lock);
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else
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{
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struct hurd_userlink ulink, ctty_ulink;
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int flags = d->flags;
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io_t ctty = _hurd_port_get (&d->ctty, &ctty_ulink);
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io_t port = _hurd_port_locked_get (&d->port, &ulink); /* Unlocks D. */
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if (fd2 < 0)
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{
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errno = EBADF;
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fd2 = -1;
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}
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else
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{
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/* Get a hold of the destination descriptor. */
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struct hurd_fd *d2;
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if (fd2 >= _hurd_dtablesize)
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{
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/* The table is not large enough to hold the destination
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descriptor. Enlarge it as necessary to allocate this
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descriptor. */
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__mutex_unlock (&_hurd_dtable_lock);
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/* We still hold FD1's lock, but this is safe because
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_hurd_alloc_fd will only examine the cells starting
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at FD2. */
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d2 = _hurd_alloc_fd (NULL, fd2);
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if (d2)
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__spin_unlock (&d2->port.lock);
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__mutex_lock (&_hurd_dtable_lock);
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}
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else
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{
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d2 = _hurd_dtable[fd2];
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if (d2 == NULL)
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{
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/* Must allocate a new one. We don't initialize the port
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cells with this call so that if it fails (out of
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memory), we will not have already added user
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references for the ports, which we would then have to
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deallocate. */
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d2 = _hurd_dtable[fd2] = _hurd_new_fd (MACH_PORT_NULL,
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MACH_PORT_NULL);
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}
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}
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if (d2 == NULL)
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{
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fd2 = -1;
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if (errno == EINVAL)
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errno = EBADF; /* POSIX.1-1990 6.2.1.2 ll 54-55. */
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}
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else
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{
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/* Give the ports each a user ref for the new descriptor. */
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__mach_port_mod_refs (__mach_task_self (), port,
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MACH_PORT_RIGHT_SEND, 1);
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if (ctty != MACH_PORT_NULL)
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__mach_port_mod_refs (__mach_task_self (), ctty,
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MACH_PORT_RIGHT_SEND, 1);
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/* Install the ports and flags in the new descriptor slot. */
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__spin_lock (&d2->port.lock);
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d2->flags = flags & ~FD_CLOEXEC; /* Dup clears FD_CLOEXEC. */
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_hurd_port_set (&d2->ctty, ctty);
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_hurd_port_locked_set (&d2->port, port); /* Unlocks D2. */
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}
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}
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__mutex_unlock (&_hurd_dtable_lock);
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_hurd_port_free (&d->port, &ulink, port);
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if (ctty != MACH_PORT_NULL)
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_hurd_port_free (&d->ctty, &ctty_ulink, port);
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}
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HURD_CRITICAL_END;
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return fd2;
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}
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weak_alias (__dup2, dup2)
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