Detect backspace by looking at termios VERASE and translate it into \177 (which

matches screen's behaviour if not its termcap/terminfo entry). The terminfo kbs
cap is often wrong or missing so it can't be used, and just assuming \177 may
be wrong.

5 files changed, 22 insertions, 4 deletions

diff --git a/input-keys.c b/input-keys.c
index 0afe6e47..30e2be05 100644
--- a/input-keys.c
+++ b/input-keys.c
@@ -36,6 +36,9 @@ struct input_key_ent {
 };
 
 struct input_key_ent input_keys[] = {
+	/* Backspace key. */
+	{ KEYC_BSPACE, "\177",	   0 },
+
 	/* Function keys. */
 	{ KEYC_F1,     "\033OP",   INPUTKEY_CTRL|INPUTKEY_XTERM },
 	{ KEYC_F2,     "\033OQ",   INPUTKEY_CTRL|INPUTKEY_XTERM },
diff --git a/key-string.c b/key-string.c
index 23aa6ad7..5c8ce5b3 100644
--- a/key-string.c
+++ b/key-string.c
@@ -57,7 +57,7 @@ struct {
 	{ "PPage",	KEYC_PPAGE },
 	{ "Tab",	'\011' },
 	{ "BTab",	KEYC_BTAB },
-	{ "BSpace",	'\177' },
+	{ "BSpace",	KEYC_BSPACE },
 
 	/* Arrow keys. */
 	{ "Up",		KEYC_UP },
diff --git a/mode-key.c b/mode-key.c
index 9db6d86c..9e5720eb 100644
--- a/mode-key.c
+++ b/mode-key.c
@@ -70,7 +70,7 @@ mode_key_lookup_vi(struct mode_key_data *mdata, int key)
 				mdata->flags &= ~MODEKEY_EDITMODE;
 			return (MODEKEYCMD_NONE);
 		case '\010':
-		case '\177':
+		case KEYC_BSPACE:
 			return (MODEKEYCMD_BACKSPACE);
 		case '\011':
 			return (MODEKEYCMD_COMPLETE);
@@ -84,7 +84,7 @@ mode_key_lookup_vi(struct mode_key_data *mdata, int key)
 
 	switch (key) {
 	case '\010':
-	case '\177':
+	case KEYC_BSPACE:
 		return (MODEKEYCMD_LEFT);
 	case KEYC_DC:
 		return (MODEKEYCMD_DELETE);
@@ -151,7 +151,7 @@ mode_key_lookup_emacs(struct mode_key_data *mdata, int key)
 {
 	switch (key) {
 	case '\010':
-	case '\177':
+	case KEYC_BSPACE:
 		return (MODEKEYCMD_BACKSPACE);
 	case '\004':
 	case KEYC_DC:
diff --git a/tmux.h b/tmux.h
index 159711e7..046e6a19 100644
--- a/tmux.h
+++ b/tmux.h
@@ -121,6 +121,9 @@ enum key_code {
 	/* Mouse key. */
 	KEYC_MOUSE = 0x1000,
 
+	/* Backspace key. */
+	KEYC_BSPACE,
+
 	/* Function keys. */
 	KEYC_F1,
 	KEYC_F2,
diff --git a/tty-keys.c b/tty-keys.c
index 5e207aa6..f25dc169 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -20,6 +20,8 @@
 #include <sys/time.h>
 
 #include <string.h>
+#include <termios.h>
+#include <unistd.h>
 
 #include "tmux.h"
 
@@ -235,6 +237,7 @@ tty_keys_next(struct tty *tty, int *key, u_char *mouse)
 	struct timeval	 tv;
 	char		*buf;
 	size_t		 len, size;
+	cc_t		 bspace;
 
 	buf = BUFFER_OUT(tty->in);
 	len = BUFFER_USED(tty->in);
@@ -245,6 +248,15 @@ tty_keys_next(struct tty *tty, int *key, u_char *mouse)
 	/* If a normal key, return it. */
 	if (*buf != '\033') {
 		*key = buffer_read8(tty->in);
+
+		/*
+		 * Check for backspace key using termios VERASE - the terminfo
+		 * kbs entry is extremely unreliable, so cannot be safely
+		 * used. termios should have a better idea.
+		 */
+		bspace = tty->tio.c_cc[VERASE];
+		if (bspace != _POSIX_VDISABLE && *key == bspace)
+			*key = KEYC_BSPACE;
 		goto found;
 	}