static void
check_one_fd (int fd, int mode)
{
struct hurd_fd *d;
d = _hurd_fd_get (fd);
if (d == NULL)
{
/* This descriptor hasn't been opened. We try to allocate the
descriptor and open /dev/null on it so that the SUID program
we are about to start does not accidentally use this
descriptor. */
d = _hurd_alloc_fd (NULL, fd);
if (d != NULL)
{
mach_port_t port;
port = __file_name_lookup (_PATH_DEVNULL, mode, 0);
if (port)
{
/* Since /dev/null isn't supposed to be a terminal, we
avoid any ctty magic. */
d->port.port = port;
d->flags = 0;
__spin_unlock (&d->port.lock);
return;
}
}
/* We cannot even give an error message here since it would run
into the same problems. */
while (1)
/* Try for ever and ever. */
ABORT_INSTRUCTION;
}
}
/* Allocate a new file descriptor and install PORT in it. FLAGS are as for
`open'; only O_IGNORE_CTTY and O_CLOEXEC are meaningful.
If the descriptor table is full, set errno, and return -1.
If DEALLOC is nonzero, deallocate PORT first. */
int
_hurd_intern_fd (io_t port, int flags, int dealloc)
{
int fd;
struct hurd_fd *d;
HURD_CRITICAL_BEGIN;
d = _hurd_alloc_fd (&fd, 0);
if (d != NULL)
{
_hurd_port2fd (d, port, flags);
__spin_unlock (&d->port.lock);
}
HURD_CRITICAL_END;
if (d == NULL)
{
if (dealloc)
__mach_port_deallocate (__mach_task_self (), port);
return -1;
}
return fd;
}
/* Duplicate FD to FD2, closing the old FD2 and making FD2 be
open on the same file as FD is, and setting FD2's flags according to FLAGS.
Return FD2 or -1. */
int
__dup3 (int fd, int fd2, int flags)
{
struct hurd_fd *d;
/* Both passing flags different from O_CLOEXEC and FD2 being the same as FD
are invalid. */
if ((flags & ~O_CLOEXEC
|| fd2 == fd)
/* ... with the exception in case that dup2 behavior is requested: if FD
is valid and FD2 is already the same then just return it. */
&& ! (flags == -1
&& fd2 == fd))
return __hurd_fail (EINVAL);
/* Extract the ports and flags from FD. */
d = _hurd_fd_get (fd);
if (d == NULL)
return __hurd_fail (EBADF);
HURD_CRITICAL_BEGIN;
__spin_lock (&d->port.lock);
if (d->port.port == MACH_PORT_NULL)
{
__spin_unlock (&d->port.lock);
fd2 = __hurd_fail (EBADF);
}
else if (fd2 == fd)
__spin_unlock (&d->port.lock);
else
{
struct hurd_userlink ulink, ctty_ulink;
int d_flags = d->flags;
io_t ctty = _hurd_port_get (&d->ctty, &ctty_ulink);
io_t port = _hurd_port_locked_get (&d->port, &ulink); /* Unlocks D. */
if (fd2 < 0)
fd2 = __hurd_fail (EBADF);
else
{
/* Get a hold of the destination descriptor. */
struct hurd_fd *d2;
__mutex_lock (&_hurd_dtable_lock);
if (fd2 >= _hurd_dtablesize)
{
/* The table is not large enough to hold the destination
descriptor. Enlarge it as necessary to allocate this
descriptor. */
__mutex_unlock (&_hurd_dtable_lock);
d2 = _hurd_alloc_fd (NULL, fd2);
if (d2)
__spin_unlock (&d2->port.lock);
__mutex_lock (&_hurd_dtable_lock);
}
else
{
d2 = _hurd_dtable[fd2];
if (d2 == NULL)
{
/* Must allocate a new one. We don't initialize the port
cells with this call so that if it fails (out of
memory), we will not have already added user
references for the ports, which we would then have to
deallocate. */
d2 = _hurd_dtable[fd2] = _hurd_new_fd (MACH_PORT_NULL,
MACH_PORT_NULL);
}
}
__mutex_unlock (&_hurd_dtable_lock);
if (d2 == NULL)
{
fd2 = -1;
if (errno == EINVAL)
errno = EBADF; /* POSIX.1-1990 6.2.1.2 ll 54-55. */
}
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 slot. */
__spin_lock (&d2->port.lock);
if (flags & O_CLOEXEC)
d2->flags = d_flags | FD_CLOEXEC;
else
/* dup clears FD_CLOEXEC. */
d2->flags = d_flags & ~FD_CLOEXEC;
_hurd_port_set (&d2->ctty, ctty);
_hurd_port_locked_set (&d2->port, port); /* Unlocks D2. */
}
}
_hurd_port_free (&d->port, &ulink, port);
if (ctty != MACH_PORT_NULL)
_hurd_port_free (&d->ctty, &ctty_ulink, port);
}
HURD_CRITICAL_END;
return fd2;
}