libbb: consolidate the code to set termios unbuffered mode

function                                             old     new   delta
set_termios_to_raw                                     -     116    +116
count_lines                                           72      74      +2
powertop_main                                       1458    1430     -28
top_main                                             943     914     -29
more_main                                            759     714     -45
fsck_minix_main                                     2969    2921     -48
conspy_main                                         1197    1135     -62
rawmode                                               99      36     -63
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/6 up/down: 118/-275)         Total: -157 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

15 files changed, 71 insertions, 55 deletions

diff --git a/editors/vi.c b/editors/vi.c
index b56b04bdd..1e5ef44fb 100644
--- a/editors/vi.c
+++ b/editors/vi.c
@@ -354,7 +354,7 @@ struct globals {
 #if ENABLE_FEATURE_VI_USE_SIGNALS
 	sigjmp_buf restart;     // catch_sig()
 #endif
-	struct termios term_orig, term_vi; // remember what the cooked mode was
+	struct termios term_orig; // remember what the cooked mode was
 #if ENABLE_FEATURE_VI_COLON
 	char *initial_cmds[3];  // currently 2 entries, NULL terminated
 #endif
@@ -462,7 +462,6 @@ struct globals {
 #define context_end    (G.context_end   )
 #define restart        (G.restart       )
 #define term_orig      (G.term_orig     )
-#define term_vi        (G.term_vi       )
 #define initial_cmds   (G.initial_cmds  )
 #define readbuffer     (G.readbuffer    )
 #define scr_out_buf    (G.scr_out_buf   )
@@ -2731,15 +2730,9 @@ static char *swap_context(char *p) // goto new context for '' command make this
 //----- Set terminal attributes --------------------------------
 static void rawmode(void)
 {
-	tcgetattr(0, &term_orig);
-	term_vi = term_orig;
-	term_vi.c_lflag &= (~ICANON & ~ECHO);	// leave ISIG on - allow intr's
-	term_vi.c_iflag &= (~IXON & ~ICRNL);
-	term_vi.c_oflag &= (~ONLCR);
-	term_vi.c_cc[VMIN] = 1;
-	term_vi.c_cc[VTIME] = 0;
-	erase_char = term_vi.c_cc[VERASE];
-	tcsetattr_stdin_TCSANOW(&term_vi);
+	// no TERMIOS_CLEAR_ISIG: leave ISIG on - allow signals
+	set_termios_to_raw(STDIN_FILENO, &term_orig, TERMIOS_RAW_CRNL);
+	erase_char = term_orig.c_cc[VERASE];
 }
 
 static void cookmode(void)
diff --git a/include/libbb.h b/include/libbb.h
index abdc8c2b8..87f89c76d 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1438,6 +1438,10 @@ int get_terminal_width_height(int fd, unsigned *width, unsigned *height) FAST_FU
 int get_terminal_width(int fd) FAST_FUNC;
 
 int tcsetattr_stdin_TCSANOW(const struct termios *tp) FAST_FUNC;
+#define TERMIOS_CLEAR_ISIG (1 << 0)
+#define TERMIOS_RAW_CRNL   (1 << 1)
+#define TERMIOS_RAW_INPUT  (1 << 2)
+int set_termios_to_raw(int fd, struct termios *oldterm, int flags) FAST_FUNC;
 
 /* NB: "unsigned request" is crucial! "int request" will break some arches! */
 int ioctl_or_perror(int fd, unsigned request, void *argp, const char *fmt,...) __attribute__ ((format (printf, 4, 5))) FAST_FUNC;
diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index 31e392147..2a5d4e704 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -2325,7 +2325,7 @@ int FAST_FUNC read_line_input(line_input_t *st, const char *prompt, char *comman
 	/* ~ECHO, ~ECHONL: turn off echoing, including newline echoing */
 	/* ~ISIG: turn off INTR (ctrl-C), QUIT, SUSP */
 	new_settings.c_lflag &= ~(ICANON | ECHO | ECHONL | ISIG);
-	/* reads would block only if < 1 char is available */
+	/* reads will block only if < 1 char is available */
 	new_settings.c_cc[VMIN] = 1;
 	/* no timeout (reads block forever) */
 	new_settings.c_cc[VTIME] = 0;
diff --git a/libbb/xfuncs.c b/libbb/xfuncs.c
index 45650edba..98d3531d6 100644
--- a/libbb/xfuncs.c
+++ b/libbb/xfuncs.c
@@ -311,6 +311,43 @@ int FAST_FUNC tcsetattr_stdin_TCSANOW(const struct termios *tp)
 	return tcsetattr(STDIN_FILENO, TCSANOW, tp);
 }
 
+int FAST_FUNC set_termios_to_raw(int fd, struct termios *oldterm, int flags)
+{
+//TODO: lineedit, microcom and less might be adapted to use this too:
+// grep for "tcsetattr"
+
+	struct termios newterm;
+
+	tcgetattr(fd, oldterm);
+	newterm = *oldterm;
+
+	/* Turn off buffered input (ICANON)
+	 * Turn off echoing (ECHO)
+	 * and separate echoing of newline (ECHONL, normally off anyway)
+	 */
+	newterm.c_lflag &= ~(ICANON | ECHO | ECHONL);
+	if (flags & TERMIOS_CLEAR_ISIG) {
+		/* dont recognize INT/QUIT/SUSP chars */
+		newterm.c_lflag &= ~ISIG;
+	}
+	/* reads will block only if < 1 char is available */
+	newterm.c_cc[VMIN] = 1;
+	/* no timeout (reads block forever) */
+	newterm.c_cc[VTIME] = 0;
+	if (flags & TERMIOS_RAW_CRNL) {
+		/* dont convert CR to NL on input */
+		newterm.c_iflag &= ~(IXON | ICRNL);
+		/* dont convert NL to CR on output */
+		newterm.c_oflag &= ~(ONLCR);
+	}
+	if (flags & TERMIOS_RAW_INPUT) {
+		/* dont convert anything on input */
+		newterm.c_iflag &= ~(BRKINT|INLCR|ICRNL|IXON|IXOFF|IUCLC|IXANY|IMAXBEL);
+	}
+
+	return tcsetattr(fd, TCSANOW, &newterm);
+}
+
 pid_t FAST_FUNC safe_waitpid(pid_t pid, int *wstat, int options)
 {
 	pid_t r;
diff --git a/loginutils/getty.c b/loginutils/getty.c
index 162c1697e..ba6c784a3 100644
--- a/loginutils/getty.c
+++ b/loginutils/getty.c
@@ -316,7 +316,7 @@ static void init_tty_attrs(int speed)
 	/* non-raw output; add CR to each NL */
 	G.tty_attrs.c_oflag = OPOST | ONLCR;
 
-	/* reads would block only if < 1 char is available */
+	/* reads will block only if < 1 char is available */
 	G.tty_attrs.c_cc[VMIN] = 1;
 	/* no timeout (reads block forever) */
 	G.tty_attrs.c_cc[VTIME] = 0;
diff --git a/loginutils/vlock.c b/loginutils/vlock.c
index 52ae607c9..5ba6a8780 100644
--- a/loginutils/vlock.c
+++ b/loginutils/vlock.c
@@ -105,12 +105,12 @@ int vlock_main(int argc UNUSED_PARAM, char **argv)
 	ioctl(STDIN_FILENO, VT_SETMODE, &vtm);
 #endif
 
+//TODO: use set_termios_to_raw()
 	tcgetattr(STDIN_FILENO, &oterm);
 	term = oterm;
-	term.c_iflag &= ~BRKINT;
-	term.c_iflag |= IGNBRK;
-	term.c_lflag &= ~ISIG;
-	term.c_lflag &= ~(ECHO | ECHOCTL);
+	term.c_iflag |= IGNBRK; /* ignore serial break (why? VTs don't have breaks, right?) */
+	term.c_iflag &= ~BRKINT; /* redundant? "dont translate break to SIGINT" */
+	term.c_lflag &= ~(ISIG | ECHO | ECHOCTL); /* ignore ^C ^Z, echo off */
 	tcsetattr_stdin_TCSANOW(&term);
 
 	while (1) {
diff --git a/miscutils/chat.c b/miscutils/chat.c
index dc85f82fb..8df194534 100644
--- a/miscutils/chat.c
+++ b/miscutils/chat.c
@@ -213,6 +213,7 @@ int chat_main(int argc UNUSED_PARAM, char **argv)
 		, signal_handler);
 
 #if ENABLE_FEATURE_CHAT_TTY_HIFI
+//TODO: use set_termios_to_raw()
 	tcgetattr(STDIN_FILENO, &tio);
 	tio0 = tio;
 	cfmakeraw(&tio);
diff --git a/miscutils/conspy.c b/miscutils/conspy.c
index d9d09d482..1f0278b47 100644
--- a/miscutils/conspy.c
+++ b/miscutils/conspy.c
@@ -363,7 +363,6 @@ int conspy_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int conspy_main(int argc UNUSED_PARAM, char **argv)
 {
 	char tty_name[sizeof(DEV_TTY "NN")];
-	struct termios termbuf;
 	unsigned opts;
 	unsigned ttynum;
 	int poll_timeout_ms;
@@ -414,16 +413,14 @@ int conspy_main(int argc UNUSED_PARAM, char **argv)
 
 	bb_signals(BB_FATAL_SIGS, cleanup);
 
-	// All characters must be passed through to us unaltered
 	G.kbd_fd = xopen(CURRENT_TTY, O_RDONLY);
-	tcgetattr(G.kbd_fd, &G.term_orig);
-	termbuf = G.term_orig;
-	termbuf.c_iflag &= ~(BRKINT|INLCR|ICRNL|IXON|IXOFF|IUCLC|IXANY|IMAXBEL);
-	//termbuf.c_oflag &= ~(OPOST); - no, we still want \n -> \r\n
-	termbuf.c_lflag &= ~(ISIG|ICANON|ECHO);
-	termbuf.c_cc[VMIN] = 1;
-	termbuf.c_cc[VTIME] = 0;
-	tcsetattr(G.kbd_fd, TCSANOW, &termbuf);
+
+	// All characters must be passed through to us unaltered
+	set_termios_to_raw(G.kbd_fd, &G.term_orig, 0
+		| TERMIOS_CLEAR_ISIG // no signals on ^C ^Z etc
+		| TERMIOS_RAW_INPUT  // turn off all input conversions
+	);
+	//Note: termios.c_oflag &= ~(OPOST); - no, we still want \n -> \r\n
 
 	poll_timeout_ms = 250;
 	while (1) {
diff --git a/miscutils/microcom.c b/miscutils/microcom.c
index 04605d883..5a4bbefa9 100644
--- a/miscutils/microcom.c
+++ b/miscutils/microcom.c
@@ -33,6 +33,7 @@
 // set raw tty mode
 static void xget1(int fd, struct termios *t, struct termios *oldt)
 {
+//TODO: use set_termios_to_raw()
 	tcgetattr(fd, oldt);
 	*t = *oldt;
 	cfmakeraw(t);
diff --git a/miscutils/rx.c b/miscutils/rx.c
index 660f66a89..36fc20a72 100644
--- a/miscutils/rx.c
+++ b/miscutils/rx.c
@@ -263,6 +263,7 @@ int rx_main(int argc UNUSED_PARAM, char **argv)
 
 	termios_err = tcgetattr(read_fd, &tty);
 	if (termios_err == 0) {
+//TODO: use set_termios_to_raw()
 		orig_tty = tty;
 		cfmakeraw(&tty);
 		tcsetattr(read_fd, TCSAFLUSH, &tty);
diff --git a/procps/powertop.c b/procps/powertop.c
index ce85f4191..ee806161f 100644
--- a/procps/powertop.c
+++ b/procps/powertop.c
@@ -683,7 +683,6 @@ int powertop_main(int UNUSED_PARAM argc, char UNUSED_PARAM **argv)
 	ullong cur_duration[MAX_CSTATE_COUNT];
 	char cstate_lines[MAX_CSTATE_COUNT + 2][64];
 #if ENABLE_FEATURE_USE_TERMIOS
-	struct termios new_settings;
 	struct pollfd pfd[1];
 
 	pfd[0].fd = 0;
@@ -707,14 +706,11 @@ int powertop_main(int UNUSED_PARAM argc, char UNUSED_PARAM **argv)
 	puts("Collecting data for "DEFAULT_SLEEP_STR" seconds");
 
 #if ENABLE_FEATURE_USE_TERMIOS
-	tcgetattr(0, (void *)&G.init_settings);
-	memcpy(&new_settings, &G.init_settings, sizeof(new_settings));
-	/* Turn on unbuffered input, turn off echoing */
-	new_settings.c_lflag &= ~(ISIG | ICANON | ECHO | ECHONL);
+	/* Turn on unbuffered input; turn off echoing, ^C ^Z etc */
+	set_termios_to_raw(STDIN_FILENO, &G.init_settings, TERMIOS_CLEAR_ISIG);
+	bb_signals(BB_FATAL_SIGS, sig_handler);
 	/* So we don't forget to reset term settings */
 	atexit(reset_term);
-	bb_signals(BB_FATAL_SIGS, sig_handler);
-	tcsetattr_stdin_TCSANOW(&new_settings);
 #endif
 
 	/* Collect initial data */
diff --git a/procps/top.c b/procps/top.c
index 491acb574..91bb8a883 100644
--- a/procps/top.c
+++ b/procps/top.c
@@ -1089,9 +1089,6 @@ int top_main(int argc UNUSED_PARAM, char **argv)
 	unsigned interval;
 	char *str_interval, *str_iterations;
 	unsigned scan_mask = TOP_MASK;
-#if ENABLE_FEATURE_USE_TERMIOS
-	struct termios new_settings;
-#endif
 
 	INIT_G();
 
@@ -1141,11 +1138,8 @@ int top_main(int argc UNUSED_PARAM, char **argv)
 	}
 #if ENABLE_FEATURE_USE_TERMIOS
 	else {
-		tcgetattr(0, (void *) &initial_settings);
-		memcpy(&new_settings, &initial_settings, sizeof(new_settings));
-		/* unbuffered input, turn off echo */
-		new_settings.c_lflag &= ~(ISIG | ICANON | ECHO | ECHONL);
-		tcsetattr_stdin_TCSANOW(&new_settings);
+		/* Turn on unbuffered input; turn off echoing, ^C ^Z etc */
+		set_termios_to_raw(STDIN_FILENO, &initial_settings, TERMIOS_CLEAR_ISIG);
 	}
 
 	bb_signals(BB_FATAL_SIGS, sig_catcher);
diff --git a/shell/shell_common.c b/shell/shell_common.c
index 98d862744..549b17ca1 100644
--- a/shell/shell_common.c
+++ b/shell/shell_common.c
@@ -143,7 +143,7 @@ shell_builtin_read(void FAST_FUNC (*setvar)(const char *name, const char *val),
 			// Setting it to more than 1 breaks poll():
 			// it blocks even if there's data. !??
 			//tty.c_cc[VMIN] = nchars < 256 ? nchars : 255;
-			/* reads would block only if < 1 char is available */
+			/* reads will block only if < 1 char is available */
 			tty.c_cc[VMIN] = 1;
 			/* no timeout (reads block forever) */
 			tty.c_cc[VTIME] = 0;
diff --git a/util-linux/fsck_minix.c b/util-linux/fsck_minix.c
index 0eaac17c0..2ab7530ea 100644
--- a/util-linux/fsck_minix.c
+++ b/util-linux/fsck_minix.c
@@ -1226,7 +1226,6 @@ void check2(void);
 int fsck_minix_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int fsck_minix_main(int argc UNUSED_PARAM, char **argv)
 {
-	struct termios tmp;
 	int retcode = 0;
 
 	xfunc_error_retval = 8;
@@ -1271,10 +1270,7 @@ int fsck_minix_main(int argc UNUSED_PARAM, char **argv)
 	read_tables();
 
 	if (OPT_manual) {
-		tcgetattr(0, &sv_termios);
-		tmp = sv_termios;
-		tmp.c_lflag &= ~(ICANON | ECHO);
-		tcsetattr_stdin_TCSANOW(&tmp);
+		set_termios_to_raw(STDIN_FILENO, &sv_termios, 0);
 		termios_set = 1;
 	}
 
diff --git a/util-linux/more.c b/util-linux/more.c
index 7fa60bdba..debad81bd 100644
--- a/util-linux/more.c
+++ b/util-linux/more.c
@@ -43,7 +43,6 @@ struct globals {
 	unsigned terminal_width;
 	unsigned terminal_height;
 	struct termios initial_settings;
-	struct termios new_settings;
 } FIX_ALIASING;
 #define G (*(struct globals*)bb_common_bufsiz1)
 #define INIT_G() do { setup_common_bufsiz(); } while (0)
@@ -101,12 +100,9 @@ int more_main(int argc UNUSED_PARAM, char **argv)
 		return bb_cat(argv);
 
 	G.tty_fileno = fileno(tty);
-	tcgetattr(G.tty_fileno, &G.initial_settings);
-	G.new_settings = G.initial_settings;
-	G.new_settings.c_lflag &= ~(ICANON | ECHO);
-	G.new_settings.c_cc[VMIN] = 1;
-	G.new_settings.c_cc[VTIME] = 0;
-	tcsetattr_tty_TCSANOW(&G.new_settings);
+
+	/* Turn on unbuffered input; turn off echoing */
+	set_termios_to_raw(G.tty_fileno, &G.initial_settings, 0);
 	bb_signals(BB_FATAL_SIGS, gotsig);
 
 	do {