X-Git-Url: http://rtime.felk.cvut.cz/gitweb/can-benchmark.git/blobdiff_plain/e6d19b5adde38dac0ab7020fcb4de75abe06ba5e..1c379cb3292ef06cf2c81a890f6af13003c90f3c:/utils/sterm.c

diff --git a/utils/sterm.c b/utils/sterm.c
index bbd80da..305a985 100644
--- a/utils/sterm.c
+++ b/utils/sterm.c
@@ -1,10 +1,5 @@
 /*
- * Simple terminal
- *
- * This is a minimalist terminal program like minicom or cu. The only
- * thing it does is creating a bidirectional connection between
- * stdin/stdout and a device (e.g. serial terminal). It can also set
- * serial line baudrate and manipulate DTR/RTS modem lines.
+ * Simple serial terminal
  *
  * Copyright 2014 Michal Sojka <sojkam1@fel.cvut.cz>
  *
@@ -23,6 +18,17 @@
  * <http://www.gnu.org/licenses/>.
  */
 
+/*
+ * This is a minimalist terminal program like minicom or cu. The only
+ * thing it does is creating a bidirectional connection between
+ * stdin/stdout and a device (e.g. serial terminal). It can also set
+ * serial line baudrate and manipulate DTR/RTS modem lines.
+ *
+ * The -d and -r option create short pulse on DTR/RTS. The lines are
+ * always raised when the device is opened and those options lower the
+ * lines immediately after opening.
+ */
+
 #define _BSD_SOURCE
 #include <sys/ioctl.h>
 #include <unistd.h>
@@ -44,6 +50,7 @@
 #define VERBOSE(format, ...) do { if (verbose) fprintf(stderr, format, ##__VA_ARGS__); } while (0)
 
 bool verbose = false;
+bool exit_on_escape = true;
 
 char template[] = "/var/lock/TMPXXXXXX";
 char lockfile[100];
@@ -64,9 +71,52 @@ void restore_stdin_term()
 
 void sighandler(int arg)
 {
-	exit(0);
+	exit(0); /* Invoke exit handlers */
+}
+
+int dtr_rts_arg(const char option)
+{
+	int val = -1;
+
+	if (optarg) {
+		switch (optarg[0]) {
+		case '+': val = +1; break;
+		case '-': val = -1; break;
+		default:
+			fprintf(stderr, "Unknown -%c argument: %s", option, optarg);
+			exit(1);
+		}
+	}
+	return val;
+}
+
+void exit_on_escapeseq(const char *buf, int len)
+{
+	static const char escseq[] = "\r~.";
+	static const char *state = escseq+1;
+	int i;
+
+	for (i = 0; i < len; i++) {
+		if (buf[i] == *state) {
+			state++;
+			if (*state == 0)
+				exit(0);
+		} else
+			state = escseq;
+	}
 }
 
+void usage(const char* argv0)
+{
+	fprintf(stderr, "Usage: %s [options] <device>\n", argv0);
+	fprintf(stderr, "Options:\n");
+	fprintf(stderr, "  -d [+|-] create short positive/negative pulse on DTR\n");
+	fprintf(stderr, "  -e       ignore '~.' escape sequence\n");
+	fprintf(stderr, "  -n       do not switch the device to raw mode\n");
+	fprintf(stderr, "  -r [+|-] create short positive/negative pulse on RTS\n");
+	fprintf(stderr, "  -s <baudrate>\n");
+	fprintf(stderr, "  -v       verbose\n");
+}
 
 int main(int argc, char *argv[])
 {
@@ -74,7 +124,6 @@ int main(int argc, char *argv[])
 	char *dev = NULL;
 	int opt;
 	speed_t speed = 0;
-	int ret;
 	int dtr = 0, rts = 0;
 	struct termios tio;
 	bool stdin_tty;
@@ -85,16 +134,12 @@ int main(int argc, char *argv[])
 		atexit(restore_stdin_term);
 	}
 
-	while ((opt = getopt(argc, argv, "ndrs:v")) != -1) {
+	while ((opt = getopt(argc, argv, "nd::er::s:v")) != -1) {
 		switch (opt) {
-		case 'd':
-			dtr = 1;
-			break;
-		case 'n':
-			raw = false;
-		case 'r':
-			rts = 1;
-			break;
+		case 'd': dtr = dtr_rts_arg(opt); break;
+		case 'e': exit_on_escape = false; break;
+		case 'n': raw = false; break;
+		case 'r': rts = dtr_rts_arg(opt); break;
 		case 's': {
 			int s = atoi(optarg);
 			switch (s) {
@@ -129,7 +174,7 @@ int main(int argc, char *argv[])
 			verbose = true;
 			break;
 		default: /* '?' */
-			fprintf(stderr, "Usage: %s [-s baudrate] [-v] <device>\n", argv[0]);
+			usage(argv[0]);
 			exit(1);
 		}
 	}
@@ -139,6 +184,7 @@ int main(int argc, char *argv[])
 
 	if (!dev) {
 		fprintf(stderr, "No device specified\n");
+		usage(argv[0]);
 		exit(1);
 	}
 
@@ -158,9 +204,21 @@ int main(int argc, char *argv[])
 		CHECK(write(tmp, pid, strlen(pid)));
 		close(tmp);
 		snprintf(lockfile, sizeof(lockfile), "/var/lock/LCK..%s", dev + 5);
+	retry:
 		if (link(template, lockfile) == -1) {
-			perror(lockfile);
-			exit(1);
+			tmp = CHECK(open(lockfile, O_RDONLY));
+			CHECK(read(tmp, pid, sizeof(pid)));
+			close(tmp);
+			int p = atoi(pid);
+			char proc[50];
+			snprintf(proc, sizeof(proc), "/proc/%d", p);
+			if (access(proc, F_OK) == 0) {
+				fprintf(stderr, "%s is used by PID %d\n", dev, p);
+				exit(1);
+			}
+			fprintf(stderr, "Stale lock file %s (PID %d) - removing it!\n", lockfile, p);
+			CHECK(unlink(lockfile));
+			goto retry;
 		}
 		rm_file(0, template);
 		on_exit(rm_file, lockfile);
@@ -185,13 +243,13 @@ int main(int argc, char *argv[])
 
 		if (dtr || rts) {
 			int status;
-			tio.c_cflag &= ~HUPCL;
+			/* tio.c_cflag &= ~HUPCL; */ /* Don't lower DTR/RTS on close */
 
 			CHECK(ioctl(fd, TIOCMGET, &status));
-			if (dtr == +1) status &= ~TIOCM_DTR;
-			if (dtr == -1) status |=  TIOCM_DTR;
-			if (rts == +1) status &= ~TIOCM_RTS;
-			if (rts == -1) status |=  TIOCM_RTS;
+			if (dtr == -1) status &= ~TIOCM_DTR;
+			if (dtr == +1) status |=  TIOCM_DTR;
+			if (rts == -1) status &= ~TIOCM_RTS;
+			if (rts == +1) status |=  TIOCM_RTS;
 			CHECK(ioctl(fd, TIOCMSET, &status));
 		}
 
@@ -217,13 +275,15 @@ int main(int argc, char *argv[])
 	VERBOSE("Connected.\n");
 	while (1) {
 		int r1, r2;
-		ret = CHECK(poll(fds, 2, -1));
+		CHECK(poll(fds, 2, -1));
 		if (fds[0].revents & POLLIN) {
 			r1 = CHECK(read(0, buf, sizeof(buf)));
 			if (r1 == 0) {
 				VERBOSE("EOF on stdin\n");
 				break;
 			}
+			if (exit_on_escape)
+				exit_on_escapeseq(buf, r1);
 			r2 = CHECK(write(fd, buf, r1));
 			if (r1 != r2) {
 				fprintf(stderr, "Not all data written to %s (%d/%d)\n", dev, r1, r2);