1 /*
2 * Copyright (c) 2018, Oticon A/S
3 * Copyright (c) 2023, Nordic Semiconductor ASA
4 *
5 * SPDX-License-Identifier: Apache-2.0
6 */
7
8 #undef _XOPEN_SOURCE
9 /* Note: This is used only for interaction with the host C library, and is therefore exempt of
10 * coding guidelines rule A.4&5 which applies to the embedded code using embedded libraries
11 */
12 #define _XOPEN_SOURCE 600
13
14 #include <stdbool.h>
15 #include <errno.h>
16 #include <stddef.h>
17 #include <stdlib.h>
18 #include <stdio.h>
19 #include <string.h>
20 #include <pty.h>
21 #include <fcntl.h>
22 #include <sys/select.h>
23 #include <unistd.h>
24 #include <poll.h>
25 #include <nsi_tracing.h>
26
27 #define ERROR nsi_print_error_and_exit
28 #define WARN nsi_print_warning
29
30 /**
31 * @brief Poll the device for input.
32 *
33 * @param in_f Input file descriptor
34 * @param p_char Pointer to character.
35 *
36 * @retval 0 If a character arrived and was stored in p_char
37 * @retval -1 If no character was available to read
38 * @retval -2 if the stdin is disconnected
39 */
np_uart_stdin_poll_in_bottom(int in_f,unsigned char * p_char)40 int np_uart_stdin_poll_in_bottom(int in_f, unsigned char *p_char)
41 {
42 if (feof(stdin)) {
43 /*
44 * The stdinput is fed from a file which finished or the user
45 * pressed Ctrl+D
46 */
47 return -2;
48 }
49
50 int n = -1;
51
52 int ready;
53 fd_set readfds;
54 static struct timeval timeout; /* just zero */
55
56 FD_ZERO(&readfds);
57 FD_SET(in_f, &readfds);
58
59 ready = select(in_f+1, &readfds, NULL, NULL, &timeout);
60
61 if (ready == 0) {
62 return -1;
63 } else if (ready == -1) {
64 ERROR("%s: Error on select ()\n", __func__);
65 }
66
67 n = read(in_f, p_char, 1);
68 if ((n == -1) || (n == 0)) {
69 return -1;
70 }
71
72 return 0;
73 }
74
75 /**
76 * @brief Check if the output descriptor has something connected to the slave side
77 *
78 * @param fd file number
79 *
80 * @retval 0 Nothing connected yet
81 * @retval 1 Something connected to the slave side
82 */
np_uart_slave_connected(int fd)83 int np_uart_slave_connected(int fd)
84 {
85 struct pollfd pfd = { .fd = fd, .events = POLLHUP };
86 int ret;
87
88 ret = poll(&pfd, 1, 0);
89 if (ret == -1) {
90 int err = errno;
91 /*
92 * Possible errors are:
93 * * EINTR :A signal was received => ok
94 * * EFAULT and EINVAL: parameters/programming error
95 * * ENOMEM no RAM left
96 */
97 if (err != EINTR) {
98 ERROR("%s: unexpected error during poll, errno=%i,%s\n",
99 __func__, err, strerror(err));
100 }
101 }
102 if (!(pfd.revents & POLLHUP)) {
103 /* There is now a reader on the slave side */
104 return 1;
105 }
106 return 0;
107 }
108
109 /**
110 * Attempt to connect a terminal emulator to the slave side of the pty
111 * If -attach_uart_cmd=<cmd> is provided as a command line option, <cmd> will be
112 * used. Otherwise, the default command,
113 * CONFIG_NATIVE_UART_AUTOATTACH_DEFAULT_CMD, will be used instead
114 */
attach_to_tty(const char * slave_tty,const char * auto_attach_cmd)115 static void attach_to_tty(const char *slave_tty, const char *auto_attach_cmd)
116 {
117 char command[strlen(auto_attach_cmd) + strlen(slave_tty) + 1];
118
119 sprintf(command, auto_attach_cmd, slave_tty);
120
121 int ret = system(command);
122
123 if (ret != 0) {
124 WARN("Could not attach to the UART with \"%s\"\n", command);
125 WARN("The command returned %i\n", WEXITSTATUS(ret));
126 }
127 }
128 /**
129 * Attempt to allocate and open a new pseudoterminal
130 *
131 * Returns the file descriptor of the master side
132 * If auto_attach was set, it will also attempt to connect a new terminal
133 * emulator to its slave side.
134 */
np_uart_open_ptty(const char * uart_name,const char * auto_attach_cmd,bool do_auto_attach,bool wait_pts)135 int np_uart_open_ptty(const char *uart_name, const char *auto_attach_cmd,
136 bool do_auto_attach, bool wait_pts)
137 {
138 int master_pty;
139 char *slave_pty_name;
140 struct termios ter;
141 int err_nbr;
142 int ret;
143 int flags;
144
145 master_pty = posix_openpt(O_RDWR | O_NOCTTY);
146 if (master_pty == -1) {
147 ERROR("Could not open a new TTY for the UART\n");
148 }
149 ret = grantpt(master_pty);
150 if (ret == -1) {
151 err_nbr = errno;
152 close(master_pty);
153 ERROR("Could not grant access to the slave PTY side (%i)\n",
154 err_nbr);
155 }
156 ret = unlockpt(master_pty);
157 if (ret == -1) {
158 err_nbr = errno;
159 close(master_pty);
160 ERROR("Could not unlock the slave PTY side (%i)\n", err_nbr);
161 }
162 slave_pty_name = ptsname(master_pty);
163 if (slave_pty_name == NULL) {
164 err_nbr = errno;
165 close(master_pty);
166 ERROR("Error getting slave PTY device name (%i)\n", err_nbr);
167 }
168 /* Set the master PTY as non blocking */
169 flags = fcntl(master_pty, F_GETFL);
170 if (flags == -1) {
171 err_nbr = errno;
172 close(master_pty);
173 ERROR("Could not read the master PTY file status flags (%i)\n",
174 err_nbr);
175 }
176
177 ret = fcntl(master_pty, F_SETFL, flags | O_NONBLOCK);
178 if (ret == -1) {
179 err_nbr = errno;
180 close(master_pty);
181 ERROR("Could not set the master PTY as non-blocking (%i)\n",
182 err_nbr);
183 }
184
185 (void) err_nbr;
186
187 /*
188 * Set terminal in "raw" mode:
189 * Not canonical (no line input)
190 * No signal generation from Ctr+{C|Z..}
191 * No echoing, no input or output processing
192 * No replacing of NL or CR
193 * No flow control
194 */
195 ret = tcgetattr(master_pty, &ter);
196 if (ret == -1) {
197 ERROR("Could not read terminal driver settings\n");
198 }
199 ter.c_cc[VMIN] = 0;
200 ter.c_cc[VTIME] = 0;
201 ter.c_lflag &= ~(ICANON | ISIG | IEXTEN | ECHO);
202 ter.c_iflag &= ~(BRKINT | ICRNL | IGNBRK | IGNCR | INLCR | INPCK
203 | ISTRIP | IXON | PARMRK);
204 ter.c_oflag &= ~OPOST;
205 ret = tcsetattr(master_pty, TCSANOW, &ter);
206 if (ret == -1) {
207 ERROR("Could not change terminal driver settings\n");
208 }
209
210 nsi_print_trace("%s connected to pseudotty: %s\n",
211 uart_name, slave_pty_name);
212
213 if (wait_pts) {
214 /*
215 * This trick sets the HUP flag on the tty master, making it
216 * possible to detect a client connection using poll.
217 * The connection of the client would cause the HUP flag to be
218 * cleared, and in turn set again at disconnect.
219 */
220 ret = open(slave_pty_name, O_RDWR | O_NOCTTY);
221 if (ret == -1) {
222 err_nbr = errno;
223 ERROR("%s: Could not open terminal from the slave side (%i,%s)\n",
224 __func__, err_nbr, strerror(err_nbr));
225 }
226 ret = close(ret);
227 if (ret == -1) {
228 err_nbr = errno;
229 ERROR("%s: Could not close terminal from the slave side (%i,%s)\n",
230 __func__, err_nbr, strerror(err_nbr));
231 }
232 }
233 if (do_auto_attach) {
234 attach_to_tty(slave_pty_name, auto_attach_cmd);
235 }
236
237 return master_pty;
238 }
239
np_uart_ptty_get_stdin_fileno(void)240 int np_uart_ptty_get_stdin_fileno(void)
241 {
242 return STDIN_FILENO;
243 }
244
np_uart_ptty_get_stdout_fileno(void)245 int np_uart_ptty_get_stdout_fileno(void)
246 {
247 return STDOUT_FILENO;
248 }
249
