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commit ae237624ee1e57a8b799cadedf43b8818ee1571f Author: Alan C. Assis <[email protected]> AuthorDate: Thu Jul 23 14:35:12 2026 -0300 readline: Improve robustness of editing and escape-sequence handling Replace fragile cursor compensation with full-line redraws where needed, fix Ctrl+W buffer/screen corruption, properly consume unrecognized CSI sequences, and always clean up leaked local-echo characters from buggy serial drivers. These changes make line editing consistent across terminals while preserving existing behavior. Signed-off-by: Alan C. Assis <[email protected]> Assisted-by: Claude Code (Sonnet 5) --- system/readline/Kconfig | 5 +- system/readline/readline_common.c | 177 ++++++++++++++++++++++++++++---------- 2 files changed, 134 insertions(+), 48 deletions(-) diff --git a/system/readline/Kconfig b/system/readline/Kconfig index 1914fedaa..f4aa5612c 100644 --- a/system/readline/Kconfig +++ b/system/readline/Kconfig @@ -61,18 +61,15 @@ config READLINE_EDIT Build in support for full command-line editing using cursor keys, Home/End, Delete. Requires a VT100/ANSI-compatible terminal. -if READLINE_EDIT - config READLINE_EDIT_EMACS bool "Emacs-style control keys" default n + depends on READLINE_EDIT ---help--- Enable emacs-style control key bindings: Ctrl+A Home, Ctrl+E End, Ctrl+K kill-to-end, Ctrl+U kill-to-start, Ctrl+Left/Right word movement. -endif # READLINE_EDIT - config READLINE_CMD_HISTORY bool "Command line history" default n diff --git a/system/readline/readline_common.c b/system/readline/readline_common.c index 3345a6624..b7981a307 100644 --- a/system/readline/readline_common.c +++ b/system/readline/readline_common.c @@ -543,7 +543,7 @@ static int word_skip(FAR const char *buf, int cursor, int bound, #endif #ifdef CONFIG_READLINE_ECHO -#ifdef CONFIG_READLINE_EDIT +# ifdef CONFIG_READLINE_EDIT /**************************************************************************** * Name: redraw_line * @@ -621,9 +621,9 @@ static void redraw_tail(FAR struct rl_common_s *vtbl, FAR const char *buf, } } } -#endif /* CONFIG_READLINE_EDIT */ +# endif /* CONFIG_READLINE_EDIT */ -#ifdef CONFIG_READLINE_EDIT_EMACS_REVERSE_SEARCH +# ifdef CONFIG_READLINE_EDIT_EMACS_REVERSE_SEARCH /**************************************************************************** * Name: isearch_redraw * @@ -669,7 +669,7 @@ static void isearch_redraw(FAR struct rl_common_s *vtbl, RL_WRITE(vtbl, buf, nch); } } -#endif /* CONFIG_READLINE_EDIT_EMACS_REVERSE_SEARCH */ +# endif /* CONFIG_READLINE_EDIT_EMACS_REVERSE_SEARCH */ #endif /* CONFIG_READLINE_ECHO */ /**************************************************************************** @@ -799,13 +799,13 @@ FAR const char *readline_prompt(FAR const char *prompt) FAR const struct extmatch_vtable_s * readline_extmatch(FAR const struct extmatch_vtable_s *vtbl) { -#if (CONFIG_READLINE_MAX_EXTCMDS > 0) +# if (CONFIG_READLINE_MAX_EXTCMDS > 0) FAR const struct extmatch_vtable_s *ret = g_extmatch_vtbl; g_extmatch_vtbl = vtbl; return ret; -#else +# else return NULL; -#endif +# endif } #endif @@ -934,9 +934,9 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, bool found = isearch_find(search, searchlen, searchoffset, &searchoffset, buf, buflen, &nch); -#ifdef CONFIG_READLINE_ECHO +# ifdef CONFIG_READLINE_ECHO isearch_redraw(vtbl, search, searchlen, buf, nch, !found); -#endif +# endif } else if (ch == ASCII_BS || ch == ASCII_DEL) { @@ -956,10 +956,10 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, } } -#ifdef CONFIG_READLINE_ECHO +# ifdef CONFIG_READLINE_ECHO isearch_redraw(vtbl, search, searchlen, buf, nch, searchlen > 0 && nch == 0); -#endif +# endif } else if (ch == CTRL_G || ch == ASCII_ETX) /* ^G or ^C: cancel */ { @@ -978,9 +978,9 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, buf[nch] = '\0'; -#ifdef CONFIG_READLINE_ECHO +# ifdef CONFIG_READLINE_ECHO redraw_line(vtbl, buf, nch, cursor); -#endif +# endif } else if (ch == '\n') { @@ -1009,9 +1009,9 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, bool found = isearch_find(search, searchlen, searchoffset, &searchoffset, buf, buflen, &nch); -#ifdef CONFIG_READLINE_ECHO +# ifdef CONFIG_READLINE_ECHO isearch_redraw(vtbl, search, searchlen, buf, nch, !found); -#endif +# endif } else { @@ -1023,14 +1023,14 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, insearch = false; cursor = nch; -#ifdef CONFIG_READLINE_ECHO +# ifdef CONFIG_READLINE_ECHO redraw_line(vtbl, buf, nch, cursor); -#endif +# endif } continue; } -#endif +#endif /* CONFIG_READLINE_EDIT_EMACS_REVERSE_SEARCH */ /* Are we processing a VT100 escape sequence */ @@ -1042,19 +1042,44 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, if (escape == 3) { escape = 0; - if (ch == '~' && cursor < nch) + if (ch == '~') { - int k; - for (k = cursor + 1; k < nch; k++) - buf[k - 1] = buf[k]; - nch--; + if (cursor < nch) + { + int k; + for (k = cursor + 1; k < nch; k++) + buf[k - 1] = buf[k]; + nch--; + } + # ifdef CONFIG_READLINE_ECHO - /* Back up 1 — terminal echo of '~' advanced cursor */ + /* Delete arrives as the 4-byte sequence "ESC [ 3 ~". + * Some serial drivers only know how to suppress + * local echo for fixed 3-byte "ESC [ x" sequences + * and leak the trailing '~' as a literal character, + * silently advancing the terminal's real cursor by + * one column. redraw_line() is immune to this (and + * to any other such drift) because it always + * returns to column 0 with '\r' first, rather than + * assuming where the cursor currently is -- unlike + * a plain erase-and-rewrite-the-tail redraw, which + * only works relative to the cursor's last known + * position and has no way to recover if that + * assumption turns out to be wrong. + * + * This redraw is unconditional -- even when there + * was nothing to delete (cursor already at the true + * end, including an empty line) -- specifically so + * it also cleans up a leaked '~' in that case; only + * skipping the redraw when there is "nothing to do" + * is exactly what left a stray '~' visible on + * screen with an unpatched driver. + */ - RL_WRITE(vtbl, g_curleft, sizeof(g_curleft)); - redraw_tail(vtbl, buf, nch, cursor); + redraw_line(vtbl, buf, nch, cursor); # endif } + continue; } @@ -1117,6 +1142,35 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, } #endif /* CONFIG_READLINE_EDIT */ + if (escape == 10) /* Unrecognized CSI -- consume to final byte */ + { + if (ch >= 0x20 && ch <= 0x3f) + { + continue; /* still a parameter/intermediate byte */ + } + + /* ch is the final byte (0x40-0x7e), or something + * malformed -- either way the sequence is over now and + * is discarded; nothing was ever inserted into the + * buffer. Still issue a corrective redraw: some serial + * drivers only know how to suppress local echo for + * fixed 3-byte "ESC [ x" sequences and leak bytes from + * any longer, unrecognized sequence as literal + * characters, the same class of issue Delete has for + * its own "ESC [ 3 ~". redraw_line() cleans up any + * such leaked characters even though the buffer itself + * was never affected by them. + */ + + escape = 0; +# ifdef CONFIG_READLINE_ECHO +# ifdef CONFIG_READLINE_EDIT + redraw_line(vtbl, buf, nch, cursor); +# endif +# endif + continue; + } + /* Some terminals (e.g. xterm) use the SS3 introducer "ESC O" * rather than CSI "ESC [" for Home/End (and, in application * cursor key mode, for the arrow keys too). Recognize the @@ -1196,10 +1250,10 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, nch = 0; -#ifdef CONFIG_READLINE_ECHO +# ifdef CONFIG_READLINE_ECHO RL_PUTC(vtbl, '\r'); RL_WRITE(vtbl, g_erasetoeol, sizeof(g_erasetoeol)); -#if defined(CONFIG_READLINE_TABCOMPLETION) || defined(CONFIG_READLINE_EDIT) +# if defined(CONFIG_READLINE_TABCOMPLETION) || defined(CONFIG_READLINE_EDIT) if (g_readline_prompt != NULL) { int k; @@ -1208,8 +1262,8 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, RL_PUTC(vtbl, g_readline_prompt[k]); } } -#endif -#endif +# endif +# endif if (g_cmdhist.offset != 1) { @@ -1244,9 +1298,9 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, * using a stale, out-of-range cursor value. */ -#ifdef CONFIG_READLINE_EDIT +# ifdef CONFIG_READLINE_EDIT cursor = nch; -#endif +# endif } #endif /* CONFIG_READLINE_CMD_HISTORY */ @@ -1315,6 +1369,22 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, } #endif + /* Not one of the specific sequences recognized above. If + * this still looks like a CSI parameter or intermediate + * byte (0x20-0x3f: digits, ';', and similar), this is + * some other CSI sequence this code doesn't specifically + * know about -- keep consuming bytes until the real final + * byte (0x40-0x7e) ends it, rather than treating this + * byte as the end of the sequence and leaking whatever + * comes after it as literal input. + */ + + if (ch >= 0x20 && ch <= 0x3f) + { + escape = 10; + continue; + } + escape = 0; ch = 'a'; } @@ -1450,19 +1520,34 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, buf[nch] = '\0'; redraw_line(vtbl, buf, nch, cursor); } - else if (ch == CTRL_W) /* Ctrl+W = Kill word backward (FIXME) */ + else if (ch == CTRL_W) /* Ctrl+W = Kill word backward */ { int start, k; start = word_skip(buf, cursor, 0, false); - for (k = start; k < nch; k++) + for (k = cursor; k < nch; k++) buf[k - (cursor - start)] = buf[k]; nch -= (cursor - start); cursor = start; buf[nch] = '\0'; - redraw_tail(vtbl, buf, nch, cursor); + + /* Unlike Ctrl+K (which never moves the cursor, so erasing + * from wherever it already is is correct) and Backspace + * (which moves it by exactly one column and compensates + * with a single explicit backspace byte), Ctrl+W can move + * the cursor back by any number of columns depending on how + * long the killed word was. redraw_tail() has no way to + * express "also move left by N first"; it just erases from + * wherever the terminal's cursor already happens to be. + * Using redraw_line() instead sidesteps the whole problem + * the same way it does for Delete: it returns to column 0 + * with '\r' first, so it is correct regardless of how far + * the cursor moved. + */ + + redraw_line(vtbl, buf, nch, cursor); } -#ifdef CONFIG_READLINE_EDIT_EMACS_REVERSE_SEARCH +# ifdef CONFIG_READLINE_EDIT_EMACS_REVERSE_SEARCH else if (ch == CTRL_R && g_cmdhist.len > 0) { /* Ctrl+R = start a reverse incremental search through the @@ -1489,11 +1574,11 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, savedcursor = cursor; nch = 0; -#ifdef CONFIG_READLINE_ECHO +# ifdef CONFIG_READLINE_ECHO isearch_redraw(vtbl, search, searchlen, buf, nch, false); -#endif +# endif } -#endif /* CONFIG_READLINE_EDIT_EMACS_REVERSE_SEARCH */ +# endif /* CONFIG_READLINE_EDIT_EMACS_REVERSE_SEARCH */ #endif /* CONFIG_READLINE_EDIT_EMACS */ /* Otherwise, put the character in the line buffer if the @@ -1526,7 +1611,11 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, if (nch + 1 < buflen) { int j; - for (j = nch; j > cursor; j--) buf[j] = buf[j - 1]; + for (j = nch; j > cursor; j--) + { + buf[j] = buf[j - 1]; + } + buf[cursor] = (char)ch; nch++; cursor++; # ifdef CONFIG_READLINE_ECHO redraw_tail(vtbl, buf, nch, cursor); @@ -1534,7 +1623,7 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, } #else buf[nch++] = ch; -#endif +#endif /* CONFIG_READLINE_EDIT */ /* Check if there is room for another character and the line's * null terminator. If not then we have to end the line now. @@ -1569,14 +1658,14 @@ ssize_t readline_common(FAR struct rl_common_s *vtbl, FAR char *buf, * only in the opposite direction. */ -#ifdef CONFIG_READLINE_EDIT +# ifdef CONFIG_READLINE_EDIT if (tab_completion(vtbl, buf, buflen, &nch)) { cursor = nch; } -#else +# else tab_completion(vtbl, buf, buflen, &nch); -#endif +# endif } #endif }
