error_t
_hurd_fd_read (struct hurd_fd *fd, void *buf, size_t *nbytes, loff_t offset)
{
error_t err;
char *data;
mach_msg_type_number_t nread;
error_t readfd (io_t port)
{
return __io_read (port, &data, &nread, offset, *nbytes);
}
data = buf;
nread = *nbytes;
if (err = HURD_FD_PORT_USE (fd, _hurd_ctty_input (port, ctty, readfd)))
return err;
if (data != buf)
{
if (nread > *nbytes) /* Sanity check for bogus server. */
{
__vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
return EGRATUITOUS;
}
memcpy (buf, data, nread);
__vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
}
*nbytes = nread;
return 0;
}
/* Read the contents of the symbolic link FILE_NAME relative to FD into no more
than LEN bytes of BUF. The contents are not null-terminated.
Returns the number of characters read, or -1 for errors. */
ssize_t
readlinkat (int fd, const char *file_name, char *buf, size_t len)
{
error_t err;
file_t file;
struct stat64 st;
file = __file_name_lookup_at (fd, 0, file_name, O_READ | O_NOLINK, 0);
if (file == MACH_PORT_NULL)
return -1;
err = __io_stat (file, &st);
if (! err)
if (S_ISLNK (st.st_mode))
{
char *rbuf = buf;
err = __io_read (file, &rbuf, &len, 0, len);
if (!err && rbuf != buf)
{
memcpy (buf, rbuf, len);
__vm_deallocate (__mach_task_self (), (vm_address_t)rbuf, len);
}
}
else
err = EINVAL;
__mach_port_deallocate (__mach_task_self (), file);
return err ? __hurd_fail (err) : len;
}
/* Read up to N chars into BUF from COOKIE.
Return how many chars were read, 0 for EOF or -1 for error. */
static ssize_t
readio (void *cookie, char *buf, size_t n)
{
mach_msg_type_number_t nread;
error_t err;
char *bufp = buf;
nread = n;
if (err = __io_read ((io_t) cookie, &bufp, &nread, -1, n))
return __hurd_fail (err);
if (bufp != buf)
{
memcpy (buf, bufp, nread);
__vm_deallocate (__mach_task_self (),
(vm_address_t) bufp, (vm_size_t) nread);
}
return nread;
}
