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 {