1 /* Copyright (C) 1993-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include <errno.h>
19 #include <unistd.h>
20 #include <hurd.h>
21 #include <hurd/fd.h>
22 #include <string.h>
23
24 error_t
_hurd_fd_read(struct hurd_fd * fd,void * buf,size_t * nbytes,loff_t offset)25 _hurd_fd_read (struct hurd_fd *fd, void *buf, size_t *nbytes, loff_t offset)
26 {
27 error_t err;
28 char *data;
29 mach_msg_type_number_t nread;
30
31 error_t readfd (io_t port)
32 {
33 return __io_read (port, &data, &nread, offset, *nbytes);
34 }
35
36 data = buf;
37 nread = *nbytes;
38 if (err = HURD_FD_PORT_USE_CANCEL (fd, _hurd_ctty_input (port, ctty, readfd)))
39 return err;
40
41 if (data != buf)
42 {
43 if (nread > *nbytes) /* Sanity check for bogus server. */
44 {
45 __vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
46 return EGRATUITOUS;
47 }
48 memcpy (buf, data, nread);
49 __vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
50 }
51
52 *nbytes = nread;
53 return 0;
54 }
55