From a5ad77accf401578f2707ade427919e379fb4ef0 Mon Sep 17 00:00:00 2001
From: Sudeep Mohanty <sudeep.mohanty@espressif.com>
Date: Fri, 12 Jan 2024 13:43:35 +0100
Subject: [PATCH] fix(console): Fixed linenoise prompt length calculation

This commit fixes a potential issue where in the prompt length used
for the linenoise based console could be calculated as a negative
integer, leading to a console hang.

Closes https://github.com/espressif/esp-idf/issues/4924
---
 components/console/linenoise/linenoise.c | 28 +++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/components/console/linenoise/linenoise.c b/components/console/linenoise/linenoise.c
index 48e510f521..3a94e81b00 100644
--- a/components/console/linenoise/linenoise.c
+++ b/components/console/linenoise/linenoise.c
@@ -804,6 +804,23 @@ uint32_t getMillis(void) {
     return tv.tv_sec * 1000 + tv.tv_usec / 1000;
 }
 
+static inline size_t prompt_len_ignore_escape_seq(const char *prompt) {
+    size_t plen = 0;
+    bool in_escape_sequence = false;
+
+    for (; *prompt != '\0'; ++prompt) {
+        if (*prompt == '\033') {
+            in_escape_sequence = true;
+        } else if (in_escape_sequence && *prompt == 'm') {
+            in_escape_sequence = false;
+        } else if (!in_escape_sequence) {
+            ++plen;
+        }
+    }
+
+    return plen;
+}
+
 /* This function is the core of the line editing capability of linenoise.
  * It expects 'fd' to be already in "raw mode" so that every key pressed
  * will be returned ASAP to read().
@@ -839,15 +856,16 @@ static int linenoiseEdit(char *buf, size_t buflen, const char *prompt)
      * initially is just an empty string. */
     linenoiseHistoryAdd("");
 
-    int pos1 = getCursorPosition();
     if (write(out_fd, prompt,l.plen) == -1) {
         return -1;
     }
     flushWrite();
-    int pos2 = getCursorPosition();
-    if (pos1 >= 0 && pos2 >= 0) {
-        l.plen = pos2 - pos1;
-    }
+
+    /* If the prompt has been registered with ANSI escape sequences
+     * for terminal colors then we remove them from the prompt length
+     * calculation. */
+    l.plen = prompt_len_ignore_escape_seq(prompt);
+
     while(1) {
         char c;
         int nread;