diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index dcc7e13e9..0f4b28818 100755 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -172,6 +172,33 @@ char kdb_getchar(void) unreachable(); } +/** + * kdb_position_cursor() - Place cursor in the correct horizontal position + * @prompt: Nil-terminated string containing the prompt string + * @buffer: Nil-terminated string containing the entire command line + * @cp: Cursor position, pointer the character in buffer where the cursor + * should be positioned. + * + * The cursor is positioned by sending a carriage-return and then printing + * the content of the line until we reach the correct cursor position. + * + * There is some additional fine detail here. + * + * Firstly, even though kdb_printf() will correctly format zero-width fields + * we want the second call to kdb_printf() to be conditional. That keeps things + * a little cleaner when LOGGING=1. + * + * Secondly, we can't combine everything into one call to kdb_printf() since + * that renders into a fixed length buffer and the combined print could result + * in unwanted truncation. + */ +static void kdb_position_cursor(char *prompt, char *buffer, char *cp) +{ + kdb_printf("\r%s", kdb_prompt_str); + if (cp > buffer) + kdb_printf("%.*s", (int)(cp - buffer), buffer); +} + /* * kdb_read * @@ -200,7 +227,6 @@ static char *kdb_read(char *buffer, size_t bufsize) * and null byte */ char *lastchar; char *p_tmp; - char tmp; static char tmpbuffer[CMD_BUFLEN]; int len = strlen(buffer); int len_tmp; @@ -237,12 +263,8 @@ poll_again: } *(--lastchar) = '\0'; --cp; - kdb_printf("\b%s \r", cp); - tmp = *cp; - *cp = '\0'; - kdb_printf(kdb_prompt_str); - kdb_printf("%s", buffer); - *cp = tmp; + kdb_printf("\b%s ", cp); + kdb_position_cursor(kdb_prompt_str, buffer, cp); } break; case 13: /* enter */ @@ -259,19 +281,14 @@ poll_again: memcpy(tmpbuffer, cp+1, lastchar - cp - 1); memcpy(cp, tmpbuffer, lastchar - cp - 1); *(--lastchar) = '\0'; - kdb_printf("%s \r", cp); - tmp = *cp; - *cp = '\0'; - kdb_printf(kdb_prompt_str); - kdb_printf("%s", buffer); - *cp = tmp; + kdb_printf("%s ", cp); + kdb_position_cursor(kdb_prompt_str, buffer, cp); } break; case 1: /* Home */ if (cp > buffer) { - kdb_printf("\r"); - kdb_printf(kdb_prompt_str); cp = buffer; + kdb_position_cursor(kdb_prompt_str, buffer, cp); } break; case 5: /* End */ @@ -377,13 +394,9 @@ poll_again: memcpy(cp+1, tmpbuffer, lastchar - cp); *++lastchar = '\0'; *cp = key; - kdb_printf("%s\r", cp); + kdb_printf("%s", cp); ++cp; - tmp = *cp; - *cp = '\0'; - kdb_printf(kdb_prompt_str); - kdb_printf("%s", buffer); - *cp = tmp; + kdb_position_cursor(kdb_prompt_str, buffer, cp); } else { *++lastchar = '\0'; *cp++ = key;