Add modem -r flag to set baud rate

Also fix it to continue reading output, rather than exiting as soon as
the child exits... Except on macOS this still doesn't seem to work
correctly for some reason.

1 files changed, 17 insertions, 12 deletions

diff --git a/bin/modem.c b/bin/modem.c
index 5ee35822..4392e071 100644
--- a/bin/modem.c
+++ b/bin/modem.c
@@ -34,8 +34,6 @@
 typedef unsigned uint;
 typedef unsigned char byte;
 
-static const uint BaudRate = 19200;
-
 static struct termios saveTerm;
 static void restoreTerm(void) {
 	tcsetattr(STDIN_FILENO, TCSADRAIN, &saveTerm);
@@ -44,7 +42,14 @@ static void restoreTerm(void) {
 int main(int argc, char *argv[]) {
 	int error;
 
-	if (argc < 2) return EX_USAGE;
+	uint baudRate = 19200;
+	for (int opt; 0 < (opt = getopt(argc, argv, "r:"));) {
+		switch (opt) {
+			break; case 'r': baudRate = strtoul(optarg, NULL, 10);
+			break; default:  return EX_USAGE;
+		}
+	}
+	if (argc - optind < 1) return EX_USAGE;
 
 	error = tcgetattr(STDIN_FILENO, &saveTerm);
 	if (error) err(EX_IOERR, "tcgetattr");
@@ -64,8 +69,8 @@ int main(int argc, char *argv[]) {
 	if (pid < 0) err(EX_OSERR, "forkpty");
 
 	if (!pid) {
-		execvp(argv[1], &argv[1]);
-		err(EX_NOINPUT, "%s", argv[1]);
+		execvp(argv[optind], &argv[optind]);
+		err(EX_NOINPUT, "%s", argv[optind]);
 	}
 
 	byte c;
@@ -73,7 +78,7 @@ int main(int argc, char *argv[]) {
 		{ .events = POLLIN, .fd = STDIN_FILENO },
 		{ .events = POLLIN, .fd = pty },
 	};
-	while (usleep(8 * 1000000 / BaudRate), 0 < poll(fds, 2, -1)) {
+	while (usleep(8 * 1000000 / baudRate), 0 < poll(fds, 2, -1)) {
 		if (fds[0].revents) {
 			ssize_t size = read(STDIN_FILENO, &c, 1);
 			if (size < 0) err(EX_IOERR, "read(%d)", STDIN_FILENO);
@@ -84,14 +89,14 @@ int main(int argc, char *argv[]) {
 		if (fds[1].revents) {
 			ssize_t size = read(pty, &c, 1);
 			if (size < 0) err(EX_IOERR, "read(%d)", pty);
+			if (!size) break;
 			size = write(STDOUT_FILENO, &c, 1);
 			if (size < 0) err(EX_IOERR, "write(%d)", STDOUT_FILENO);
 		}
-
-		int status;
-		pid_t dead = waitpid(pid, &status, WNOHANG);
-		if (dead < 0) err(EX_OSERR, "waitpid");
-		if (dead) return WIFEXITED(status) ? WEXITSTATUS(status) : EX_SOFTWARE;
 	}
-	err(EX_IOERR, "poll");
+
+	int status;
+	pid_t dead = waitpid(pid, &status, 0);
+	if (dead < 0) err(EX_OSERR, "waitpid");
+	return WIFEXITED(status) ? WEXITSTATUS(status) : EX_SOFTWARE;
 }