140 lines
4.1 KiB
C
140 lines
4.1 KiB
C
/* Duplicate a file descriptor to a given number, with flags. Hurd version.
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Copyright (C) 1991-2022 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 Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the 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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, see <https://www.gnu.org/licenses/>. */
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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, and setting FD2's flags according to FLAGS.
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Return FD2 or -1. */
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int
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__dup3 (int fd, int fd2, int flags)
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{
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struct hurd_fd *d;
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/* Both passing flags different from O_CLOEXEC and FD2 being the same as FD
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are invalid. */
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if ((flags & ~O_CLOEXEC
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|| fd2 == fd)
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/* ... with the exception in case that dup2 behavior is requested: if FD
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is valid and FD2 is already the same then just return it. */
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&& ! (flags == -1
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&& fd2 == fd))
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return __hurd_fail (EINVAL);
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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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return __hurd_fail (EBADF);
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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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fd2 = __hurd_fail (EBADF);
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}
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else if (fd2 == fd)
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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 d_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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fd2 = __hurd_fail (EBADF);
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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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__mutex_lock (&_hurd_dtable_lock);
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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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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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__mutex_unlock (&_hurd_dtable_lock);
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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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if (flags & O_CLOEXEC)
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d2->flags = d_flags | FD_CLOEXEC;
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else
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/* dup clears FD_CLOEXEC. */
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d2->flags = d_flags & ~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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_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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libc_hidden_def (__dup3)
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weak_alias (__dup3, dup3)
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