1 /* stdio on a Mach device port.
2 Translates \n to \r\n on output, echos and translates \r to \n on input.
3 Copyright (C) 1992-2022 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20 #include <stdio.h>
21 #include <mach.h>
22 #include <device/device.h>
23 #include <errno.h>
24 #include <string.h>
25 #include <libioP.h>
26
27
28 static ssize_t
devstream_write(void * cookie,const char * buffer,size_t n)29 devstream_write (void *cookie, const char *buffer, size_t n)
30 {
31 const device_t dev = (device_t) cookie;
32
33 int write_some (const char *p, size_t to_write)
34 {
35 kern_return_t err;
36 int wrote;
37 int thiswrite;
38
39 while (to_write > 0)
40 {
41 thiswrite = to_write;
42 if (thiswrite > IO_INBAND_MAX)
43 thiswrite = IO_INBAND_MAX;
44
45 if (err = device_write_inband (dev, 0, 0, p, thiswrite, &wrote))
46 {
47 errno = err;
48 return 0;
49 }
50 p += wrote;
51 to_write -= wrote;
52 }
53 return 1;
54 }
55 int write_crlf (void)
56 {
57 static const char crlf[] = "\r\n";
58 return write_some (crlf, 2);
59 }
60
61 /* Search for newlines (LFs) in the buffer. */
62
63 const char *start = buffer, *p;
64 while ((p = memchr (start, '\n', n)) != NULL)
65 {
66 /* Found one. Write out through the preceding character,
67 and then write a CR/LF pair. */
68
69 if ((p > start && !write_some (start, p - start))
70 || !write_crlf ())
71 return (start - buffer) ?: -1;
72
73 n -= p + 1 - start;
74 start = p + 1;
75 }
76
77 /* Write the remainder of the buffer. */
78 if (write_some (start, n))
79 start += n;
80 return (start - buffer) ?: -1;
81 }
82
83 static ssize_t
devstream_read(void * cookie,char * buffer,size_t to_read)84 devstream_read (void *cookie, char *buffer, size_t to_read)
85 {
86 const device_t dev = (device_t) cookie;
87
88 kern_return_t err;
89 mach_msg_type_number_t nread = to_read;
90
91 err = device_read_inband (dev, 0, 0, to_read, buffer, &nread);
92 if (err)
93 {
94 errno = err;
95 return -1;
96 }
97
98 /* Translate CR to LF. */
99 {
100 char *p;
101 for (p = memchr (buffer, '\r', nread); p;
102 p = memchr (p + 1, '\r', (buffer + nread) - (p + 1)))
103 *p = '\n';
104 }
105
106 /* Echo back what we read. */
107 (void) devstream_write (cookie, buffer, nread);
108
109 return nread;
110 }
111
112 static int
dealloc_ref(void * cookie)113 dealloc_ref (void *cookie)
114 {
115 if (__mach_port_deallocate (mach_task_self (), (mach_port_t) cookie))
116 {
117 errno = EINVAL;
118 return -1;
119 }
120 return 0;
121 }
122
123 FILE *
mach_open_devstream(mach_port_t dev,const char * mode)124 mach_open_devstream (mach_port_t dev, const char *mode)
125 {
126 FILE *stream;
127
128 if (mach_port_mod_refs (mach_task_self (), dev, MACH_PORT_RIGHT_SEND, 1))
129 {
130 errno = EINVAL;
131 return NULL;
132 }
133
134 stream = _IO_fopencookie ((void *) dev, mode,
135 (cookie_io_functions_t) { write: devstream_write,
136 read: devstream_read,
137 close: dealloc_ref });
138 if (stream == NULL)
139 {
140 __mach_port_deallocate (mach_task_self (), dev);
141 return NULL;
142 }
143
144 return stream;
145 }
146