1 /* microcom.c - Simple serial console.
2 *
3 * Copyright 2017 The Android Open Source Project.
4
5 USE_MICROCOM(NEWTOY(microcom, "<1>1s:X", TOYFLAG_BIN))
6
7 config MICROCOM
8 bool "microcom"
9 default y
10 help
11 usage: microcom [-s SPEED] [-X] DEVICE
12
13 Simple serial console.
14
15 -s Set baud rate to SPEED
16 -X Ignore ^@ (send break) and ^] (exit).
17 */
18
19 #define FOR_microcom
20 #include "toys.h"
21
GLOBALS(char * s;int fd;struct termios original_stdin_state,original_fd_state;)22 GLOBALS(
23 char *s;
24
25 int fd;
26 struct termios original_stdin_state, original_fd_state;
27 )
28
29 // Puts `fd` into raw mode, setting the baud rate if `speed` != 0,
30 // and saving the original terminal state.
31 static void xraw(int fd, const char *name, speed_t speed,
32 struct termios *original)
33 {
34 struct termios t;
35
36 if (tcgetattr(fd, &t)) perror_exit("tcgetattr %s", name);
37 *original = t;
38
39 cfmakeraw(&t);
40 if (speed) cfsetspeed(&t, speed);
41
42 if (tcsetattr(fd, TCSAFLUSH, &t)) perror_exit("tcsetattr %s", name);
43 }
44
restore_states(int i)45 static void restore_states(int i)
46 {
47 tcsetattr(0, TCSAFLUSH, &TT.original_stdin_state);
48 tcsetattr(TT.fd, TCSAFLUSH, &TT.original_fd_state);
49 }
50
microcom_main(void)51 void microcom_main(void)
52 {
53 int speeds[] = {50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400,
54 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800,
55 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000,
56 2500000, 3000000, 3500000, 4000000};
57 struct pollfd fds[2];
58 int i, speed;
59
60 if (!TT.s) speed = 115200;
61 else speed = atoi(TT.s);
62
63 // Find speed in table, adjust to constant
64 for (i = 0; i < ARRAY_LEN(speeds); i++) if (speeds[i] == speed) break;
65 if (i == ARRAY_LEN(speeds)) error_exit("unknown speed: %s", TT.s);
66 speed = i+1+4081*(i>15);
67
68 // Open with O_NDELAY, but switch back to blocking for reads.
69 TT.fd = xopen(*toys.optargs, O_RDWR | O_NOCTTY | O_NDELAY);
70 if (-1==(i = fcntl(TT.fd, F_GETFL, 0)) || fcntl(TT.fd, F_SETFL, i&~O_NDELAY))
71 perror_exit_raw(*toys.optargs);
72
73 // Set both input and output to raw mode.
74 xraw(TT.fd, "fd", speed, &TT.original_fd_state);
75 xraw(0, "stdin", 0, &TT.original_stdin_state);
76 // ...and arrange to restore things, however we may exit.
77 sigatexit(restore_states);
78
79 fds[0].fd = TT.fd;
80 fds[0].events = POLLIN;
81 fds[1].fd = 0;
82 fds[1].events = POLLIN;
83
84 while (poll(fds, 2, -1) > 0) {
85 char buf[BUFSIZ];
86
87 // Read from connection, write to stdout.
88 if (fds[0].revents) {
89 ssize_t n = read(TT.fd, buf, sizeof(buf));
90 if (n > 0) xwrite(0, buf, n);
91 else break;
92 }
93
94 // Read from stdin, write to connection.
95 if (fds[1].revents) {
96 if (read(0, buf, 1) != 1) break;
97 if (!(toys.optflags & FLAG_X)) {
98 if (!*buf) {
99 tcsendbreak(TT.fd, 0);
100 continue;
101 } else if (*buf == (']'-'@')) break;
102 }
103 xwrite(TT.fd, buf, 1);
104 }
105 }
106 }
107