1 files changed, 104 insertions, 0 deletions
diff --git a/toys/pending/microcom.c b/toys/pending/microcom.c
new file mode 100644
index 00000000..d41a9a21
--- /dev/null
+++ b/toys/pending/microcom.c
@@ -0,0 +1,104 @@
+/* microcom.c - Simple serial console.
+ *
+ * Copyright 2017 The Android Open Source Project.
+
+USE_MICROCOM(NEWTOY(microcom, "<1>1s:X", TOYFLAG_BIN))
+
+config MICROCOM
+  bool "microcom"
+  default n
+  help
+    usage: microcom [-s SPEED] [-X]
+
+    Simple serial console.
+
+    -s  Set baud rate to SPEED
+    -X  Ignore ^@ (send break) and ^X (exit).
+*/
+
+#define FOR_microcom
+#include "toys.h"
+
+GLOBALS(
+  char *speed;
+
+  int fd;
+  struct termios original_stdin_state, original_fd_state;
+)
+
+// Puts `fd` into raw mode, setting the baud rate if `speed` != 0,
+// and saving the original terminal state.
+static void xraw(int fd, const char *name, speed_t speed,
+                 struct termios *original)
+{
+  struct termios t;
+
+  if (tcgetattr(fd, &t)) perror_exit("tcgetattr %s", name);
+  *original = t;
+
+  cfmakeraw(&t);
+  if (speed && cfsetspeed(&t, speed)) perror_exit("cfsetspeed");
+
+  if (tcsetattr(fd, TCSAFLUSH, &t)) perror_exit("tcsetattr %s", name);
+}
+
+static void restore_states(int i)
+{
+  tcsetattr(0, TCSAFLUSH, &TT.original_stdin_state);
+  tcsetattr(TT.fd, TCSAFLUSH, &TT.original_fd_state);
+}
+
+void microcom_main(void)
+{
+  speed_t speed = B115200;
+  struct pollfd fds[2];
+  int flags;
+
+  // TODO: move this into lib and support all known baud rates?
+  if (TT.speed) {
+    switch (atolx(TT.speed)) {
+    case 9600: speed = B9600; break;
+    case 19200: speed = B19200; break;
+    case 38400: speed = B38400; break;
+    case 115200: speed = B115200; break;
+    default: error_exit("unknown speed: %s", TT.speed);
+    }
+  }
+
+  // Open with O_NDELAY, but switch back to blocking for reads.
+  TT.fd = xopen(*toys.optargs, O_RDWR | O_NOCTTY | O_NDELAY);
+  flags = fcntl(TT.fd, F_GETFL, 0);
+  if (flags == -1) perror_exit("fcntl F_GETFL");
+  if (fcntl(TT.fd, F_SETFL, flags & ~O_NDELAY)) perror_exit("fcntl F_SETFL");
+
+  // Set both input and output to raw mode.
+  xraw(TT.fd, "fd", speed, &TT.original_fd_state);
+  xraw(0, "stdin", 0, &TT.original_stdin_state);
+  // ...and arrange to restore things, however we may exit.
+  sigatexit(restore_states);
+
+  fds[0].fd = TT.fd;
+  fds[0].events = POLLIN;
+  fds[1].fd = 0;
+  fds[1].events = POLLIN;
+
+  while (poll(fds, 2, -1) > 0) {
+    char buf[BUFSIZ];
+
+    // Read from connection, write to stdout.
+    if (fds[0].revents) {
+      ssize_t n = read(TT.fd, buf, sizeof(buf));
+      if (n > 0) xwrite(0, buf, n);
+      else break;
+    }
+
+    // Read from stdin, write to connection.
+    if (fds[1].revents) {
+      if (read(0, buf, 1) == 1) {
+        if (buf[0] == 0) tcsendbreak(TT.fd, 0);
+        else if (buf[0] == ('X'-'@')) break;
+        else xwrite(TT.fd, buf, 1);
+      } else break;
+    }
+  }
+}