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 |
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 |
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 |
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 * |
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 (cookie: (void *) dev, mode, |
135 | io_functions: (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 | |