X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=miscutils%2Fmicrocom.c;h=5e29a1acdd483ba51e4382807c24685f8aa1b577;hb=45dc96c8a6dce3aeea983f6c32572d4cee646b5d;hp=2857a1b1b1c2598eeafc4e8d58d7609f4ff4e75b;hpb=ffae845cfd0a0b9872827d806984841d4cfee104;p=oweals%2Fbusybox.git

diff --git a/miscutils/microcom.c b/miscutils/microcom.c
index 2857a1b1b..5e29a1acd 100644
--- a/miscutils/microcom.c
+++ b/miscutils/microcom.c
@@ -5,21 +5,24 @@
  *
  * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
  *
- * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2, see file LICENSE in this source tree.
  */
-#include "libbb.h"
 
-/* All known arches use small ints for signals */
-static volatile smallint signalled;
+//usage:#define microcom_trivial_usage
+//usage:       "[-d DELAY] [-t TIMEOUT] [-s SPEED] [-X] TTY"
+//usage:#define microcom_full_usage "\n\n"
+//usage:       "Copy bytes for stdin to TTY and from TTY to stdout\n"
+//usage:     "\n	-d	Wait up to DELAY ms for TTY output before sending every"
+//usage:     "\n		next byte to it"
+//usage:     "\n	-t	Exit if both stdin and TTY are silent for TIMEOUT ms"
+//usage:     "\n	-s	Set serial line to SPEED"
+//usage:     "\n	-X	Disable special meaning of NUL and Ctrl-X from stdin"
 
-static void signal_handler(int signo)
-{
-	signalled = signo;
-}
+#include "libbb.h"
 
 // set raw tty mode
 static void xget1(int fd, struct termios *t, struct termios *oldt)
-{ 
+{
 	tcgetattr(fd, oldt);
 	*t = *oldt;
 	cfmakeraw(t);
@@ -41,7 +44,7 @@ static int xset1(int fd, struct termios *tio, const char *device)
 }
 
 int microcom_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int microcom_main(int argc, char **argv)
+int microcom_main(int argc UNUSED_PARAM, char **argv)
 {
 	int sfd;
 	int nfd;
@@ -51,18 +54,17 @@ int microcom_main(int argc, char **argv)
 	enum {
 		OPT_X = 1 << 0, // do not respect Ctrl-X, Ctrl-@
 		OPT_s = 1 << 1, // baudrate
-		OPT_d = 1 << 2, // wait for device response, msecs
+		OPT_d = 1 << 2, // wait for device response, ms
 		OPT_t = 1 << 3, // timeout, ms
 	};
 	speed_t speed = 9600;
 	int delay = -1;
 	int timeout = -1;
+	unsigned opts;
 
 	// fetch options
-	unsigned opts;
-	opt_complementary = "=1:s+:d+:t+"; // exactly one arg should be there
+	opt_complementary = "=1:s+:d+:t+"; // exactly one arg, numeric options
 	opts = getopt32(argv, "Xs:d:t:", &speed, &delay, &timeout);
-
 //	argc -= optind;
 	argv += optind;
 
@@ -71,19 +73,18 @@ int microcom_main(int argc, char **argv)
 	device_lock_file = xasprintf("/var/lock/LCK..%s", device_lock_file);
 	sfd = open(device_lock_file, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL, 0644);
 	if (sfd < 0) {
+		// device already locked -> bail out
 		if (errno == EEXIST)
-			bb_perror_msg_and_die("can't create %s", device_lock_file);
+			bb_perror_msg_and_die("can't create '%s'", device_lock_file);
+		// can't create lock -> don't care
 		if (ENABLE_FEATURE_CLEAN_UP)
 			free(device_lock_file);
 		device_lock_file = NULL;
-	}
-	if (sfd > 0) {
-		// %4d to make mgetty happy. It treats 4-bytes lock files as binary,
+	} else {
+		// %4d to make concurrent mgetty (if any) happy.
+		// Mgetty treats 4-bytes lock files as binary,
 		// not text, PID. Making 5+ char file. Brrr...
-		char *s = xasprintf("%4d\n", getpid());
-		write(sfd, s, strlen(s));
-		if (ENABLE_FEATURE_CLEAN_UP)
-			free(s);
+		fdprintf(sfd, "%4d\n", getpid());
 		close(sfd);
 	}
 
@@ -93,32 +94,31 @@ int microcom_main(int argc, char **argv)
 		+ (1 << SIGINT)
 		+ (1 << SIGTERM)
 		+ (1 << SIGPIPE)
-		, signal_handler);
+		, record_signo);
 
 	// error exit code if we fail to open the device
-	signalled = 1;
-
-	// put stdin to "raw mode" (if stdin is a TTY),
-	// handle one character at a time
-	if (isatty(STDIN_FILENO)) {
-		xget1(STDIN_FILENO, &tio, &tio0);
-		if (xset1(STDIN_FILENO, &tio, "stdin"))
-			goto done;
-	}
+	bb_got_signal = 1;
 
 	// open device
 	sfd = open_or_warn(argv[0], O_RDWR | O_NOCTTY | O_NONBLOCK);
 	if (sfd < 0)
 		goto done;
-	fcntl(sfd, F_SETFL, 0);
+	fcntl(sfd, F_SETFL, O_RDWR);
 
 	// put device to "raw mode"
 	xget1(sfd, &tio, &tiosfd);
-//	tio.c_cflag |= (CREAD|HUPCL); // we just bail out on any device error
 	// set device speed
 	cfsetspeed(&tio, tty_value_to_baud(speed));
 	if (xset1(sfd, &tio, argv[0]))
-		goto restore0_and_done;
+		goto done;
+
+	// put stdin to "raw mode" (if stdin is a TTY),
+	// handle one character at a time
+	if (isatty(STDIN_FILENO)) {
+		xget1(STDIN_FILENO, &tio, &tio0);
+		if (xset1(STDIN_FILENO, &tio, "stdin"))
+			goto done;
+	}
 
 	// main loop: check with poll(), then read/write bytes across
 	pfd[0].fd = sfd;
@@ -126,9 +126,10 @@ int microcom_main(int argc, char **argv)
 	pfd[1].fd = STDIN_FILENO;
 	pfd[1].events = POLLIN;
 
-	signalled = 0;
+	bb_got_signal = 0;
 	nfd = 2;
-	while (!signalled && safe_poll(pfd, nfd, timeout) > 0) {
+	// Not safe_poll: we want to exit on signal
+	while (!bb_got_signal && poll(pfd, nfd, timeout) > 0) {
 		if (nfd > 1 && pfd[1].revents) {
 			char c;
 			// read from stdin -> write to device
@@ -162,7 +163,7 @@ skip_write: ;
 				full_write(STDOUT_FILENO, iobuf, len);
 			else {
 				// EOF/error -> bail out
-				signalled = SIGHUP;
+				bb_got_signal = SIGHUP;
 				break;
 			}
 		}
@@ -171,7 +172,6 @@ skip_write: ;
 	// restore device mode
 	tcsetattr(sfd, TCSAFLUSH, &tiosfd);
 
-restore0_and_done:
 	if (isatty(STDIN_FILENO))
 		tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0);
 
@@ -179,5 +179,5 @@ done:
 	if (device_lock_file)
 		unlink(device_lock_file);
 
-	return signalled;
+	return bb_got_signal;
 }