Fix microcom to set serial device's terminal correctly.

Can't use the same set_terminal() logic as ptys because it not displaying data, it should just accurately copy it.
landley · Nov 18, 2020 · c251e32 · c251e32
1 parent 0ea0498
commit c251e32
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Showing 3 changed files with 27 additions and 7 deletions.
diff --git a/lib/lib.h b/lib/lib.h
@@ -337,6 +337,7 @@ int terminal_probesize(unsigned *xx, unsigned *yy);
 #define KEY_ALT (1<<18)
 int scan_key(char *scratch, int timeout_ms);
 int scan_key_getsize(char *scratch, int timeout_ms, unsigned *xx, unsigned *yy);
+void xsetspeed(struct termios *tio, int speed);
 int set_terminal(int fd, int raw, int speed, struct termios *old);
 void xset_terminal(int fd, int raw, int speed, struct termios *old);
 void tty_esc(char *s);

diff --git a/lib/tty.c b/lib/tty.c
@@ -61,6 +61,20 @@ int terminal_probesize(unsigned *xx, unsigned *yy)
   return 0;
 }
 
+void xsetspeed(struct termios *tio, int speed)
+{
+  int i, speeds[] = {50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400,
+                    4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800,
+                    500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000,
+                    2500000, 3000000, 3500000, 4000000};
+
+  // Find speed in table, adjust to constant
+  for (i = 0; i < ARRAY_LEN(speeds); i++) if (speeds[i] == speed) break;
+  if (i == ARRAY_LEN(speeds)) error_exit("unknown speed: %d", speed);
+  cfsetspeed(tio, i+1+4081*(i>15));
+}
+
+
 // Reset terminal to known state, saving copy of old state if old != NULL.
 int set_terminal(int fd, int raw, int speed, struct termios *old)
 {

diff --git a/toys/net/microcom.c b/toys/net/microcom.c
@@ -22,30 +22,35 @@ config MICROCOM
 GLOBALS(
   long s;
 
-  int fd;
-  struct termios original_stdin_state, original_fd_state;
+  int fd, stok;
+  struct termios old_stdin, old_fd;
 )
 
 // TODO: tty_sigreset outputs ansi escape sequences, how to disable?
 static void restore_states(int i)
 {
-  tcsetattr(0, TCSAFLUSH, &TT.original_stdin_state);
-  tcsetattr(TT.fd, TCSAFLUSH, &TT.original_fd_state);
+  if (TT.stok) tcsetattr(0, TCSAFLUSH, &TT.old_stdin);
+  tcsetattr(TT.fd, TCSAFLUSH, &TT.old_fd);
 }
 
 void microcom_main(void)
 {
+  struct termios tio;
   struct pollfd fds[2];
   int i;
 
   // Open with O_NDELAY, but switch back to blocking for reads.
   TT.fd = xopen(*toys.optargs, O_RDWR | O_NOCTTY | O_NDELAY);
-  if (-1==(i = fcntl(TT.fd, F_GETFL, 0)) || fcntl(TT.fd, F_SETFL, i&~O_NDELAY))
+  if (-1==(i = fcntl(TT.fd, F_GETFL, 0)) || fcntl(TT.fd, F_SETFL, i&~O_NDELAY)
+      || tcgetattr(TT.fd, &TT.old_fd))
     perror_exit_raw(*toys.optargs);
 
   // Set both input and output to raw mode.
-  xset_terminal(TT.fd, 1, TT.s, &TT.original_fd_state);
-  set_terminal(0, 1, 0, &TT.original_stdin_state);
+  memcpy(&tio, &TT.old_fd, sizeof(struct termios));
+  cfmakeraw(&tio);
+  xsetspeed(&tio, TT.s);
+  if (tcsetattr(TT.fd, TCSAFLUSH, &tio)) perror_exit("set speed");
+  if (!set_terminal(0, 1, 0, &TT.old_stdin)) TT.stok++;
   // ...and arrange to restore things, however we may exit.
   sigatexit(restore_states);