From 47c1c50b804985913e7ca235af7bac9754354fb9 Mon Sep 17 00:00:00 2001
From: Michal Sojka <sojkam1@fel.cvut.cz>
Date: Thu, 20 Aug 2015 00:00:28 +0200
Subject: [PATCH] Add command mode

This mode is entered before serial line begins. Currently implemented
commands are: dtr, rst and go. "dtr" and "rst" are the same as -d and -r
options, "go" ends command mode and enters serial line interaction.

This is intended for use by novaboot in this way: Novaboot connects to
the serial line to be sure that the target is not occupied. Then it
copies the images, which can take long time, and after that it sends
reset command to reset the target. Without this, the target is reset (by
-d or -r) before copying the images and after that it may be too late to
communicate with the bootloader.
---
 sterm.c | 47 +++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 41 insertions(+), 6 deletions(-)

diff --git a/sterm.c b/sterm.c
index 34f4845..3e1a573 100644
--- a/sterm.c
+++ b/sterm.c
@@ -48,6 +48,7 @@
 #define TOSTRING(val) STRINGIFY(val)
 #define CHECK(cmd) ({ int ret = (cmd); if (ret == -1) { perror(#cmd " line " TOSTRING(__LINE__)); exit(1); }; ret; })
 #define CHECKPTR(cmd) ({ void *ptr = (cmd); if (ptr == (void*)-1) { perror(#cmd " line " TOSTRING(__LINE__)); exit(1); }; ptr; })
+#define CHECKNULL(cmd) ({ void *ptr = (cmd); if (ptr == NULL) { perror(#cmd " line " TOSTRING(__LINE__)); exit(1); }; ptr; })
 
 #define VERBOSE(format, ...) do { if (verbose) fprintf(stderr, "sterm: " format, ##__VA_ARGS__); } while (0)
 
@@ -80,7 +81,7 @@ void sighandler(int arg)
 	exit(0); /* Invoke exit handlers */
 }
 
-int dtr_rts_arg(const char option)
+int dtr_rts_arg(const char option, const char *optarg)
 {
 	int val = -1;
 
@@ -93,7 +94,7 @@ int dtr_rts_arg(const char option)
 			case '+': val = +1; break;
 			case '-': val = -1; break;
 			default:
-				fprintf(stderr, "Unknown -%c argument: %s", option, optarg);
+				fprintf(stderr, "Unknown -%c argument: %s\n", option, optarg);
 				exit(1);
 			}
 		}
@@ -124,6 +125,7 @@ void usage(const char* argv0)
 	fprintf(stderr, "Usage: %s [options] <device>\n", argv0);
 	fprintf(stderr,
 		"Options:\n"
+		"  -c        enter command mode\n"
 		"  -d[PULSE] make pulse on DTR\n"
 		"  -e        ignore '~.' escape sequence\n"
 		"  -n        do not switch the device to raw mode\n"
@@ -158,6 +160,33 @@ void pulse(int fd, int dtr, int rts)
 	CHECK(ioctl(fd, TIOCMSET, &status));
 }
 
+void handle_commands(int fd)
+{
+	char command[100];
+	bool go = false;
+
+	while (!go) {
+		char *p1 = NULL;
+		if (fgets(command, sizeof(command), stdin) == NULL) {
+			if (!feof(stdin))
+			    perror("Command read");
+			exit(1);
+		}
+		if (sscanf(command, "dtr %ms", &p1) == 1)
+			pulse(fd, dtr_rts_arg('d', p1), 0);
+		else if (sscanf(command, "rts %ms", &p1) == 1)
+			pulse(fd, 0, dtr_rts_arg('r', p1));
+		else if (strcmp(command, "go\n") == 0)
+			break;
+		else {
+			fprintf(stderr, "Unknown command: %s\n", command);
+			exit(1);
+		}
+
+		free(p1);
+	}
+}
+
 int main(int argc, char *argv[])
 {
 	int fd;
@@ -167,18 +196,20 @@ int main(int argc, char *argv[])
 	struct termios tio;
 	bool stdin_tty;
 	bool raw = true;
+	bool cmd = false;
 
 	if ((stdin_tty = isatty(0))) {
 		CHECK(tcgetattr(0, &stdin_tio_backup));
 		atexit(restore_stdin_term);
 	}
 
-	while ((opt = getopt(argc, argv, "nd::er::s:v")) != -1) {
+	while ((opt = getopt(argc, argv, "cnd::er::s:v")) != -1) {
 		switch (opt) {
-		case 'd': dtr = dtr_rts_arg(opt); break;
+		case 'c': cmd = true; break;
+		case 'd': dtr = dtr_rts_arg(opt, optarg); break;
 		case 'e': exit_on_escape = false; break;
 		case 'n': raw = false; break;
-		case 'r': rts = dtr_rts_arg(opt); break;
+		case 'r': rts = dtr_rts_arg(opt, optarg); break;
 		case 's': {
 			int s = atoi(optarg);
 			switch (s) {
@@ -275,6 +306,11 @@ int main(int argc, char *argv[])
 		exit(1);
 	}
 
+	VERBOSE("Connected.\r\n");
+
+	if (cmd)
+		handle_commands(fd);
+
 	struct pollfd fds[2] = {
 		{ .fd = 0,  .events = POLLIN },
 		{ .fd = fd, .events = POLLIN },
@@ -288,7 +324,6 @@ int main(int argc, char *argv[])
 		CHECK(tcsetattr(0, TCSANOW, &tio));
 	}
 
-	VERBOSE("Connected.\r\n");
 	if (exit_on_escape)
 		VERBOSE("Use '<Enter>~.' sequence to exit.\r\n");
 
-- 
2.39.2