On Sunday 21 September 2008 14:27, poly-p man wrote:
> I'm using a (somewhat) recent svn build...
>
> Found a pretty nasty bug... I'll help hunt down the code shortly..
>
> Steps to reproduce:
> Type many spaces into the command-line, hit enter
> hit up (previous command before the spaces appears).
> hit down
>
> What appears seems to be pointer overflow junk - one time it gave me "/root",
> another time it gave me random data and let me backspace into the prompt.
>
> Alone this doesn't seem like much, but could it be part of a larger bug?
Try this patch.
--
vda
diff -d -urpN busybox.3/libbb/lineedit.c busybox.4/libbb/lineedit.c
--- busybox.3/libbb/lineedit.c 2008-09-11 21:23:19.000000000 +0200
+++ busybox.4/libbb/lineedit.c 2008-09-22 00:22:46.000000000 +0200
@@ -956,24 +956,33 @@ static void input_tab(smallint *lastWasT
#if MAX_HISTORY > 0
+static void save_command_ps_at_cur_history(void)
+{
+ if (command_ps[0] != '\0') {
+ int cur = state->cur_history;
+ free(state->history[cur]);
+ state->history[cur] = xstrdup(command_ps);
+ }
+}
+
/* state->flags is already checked to be nonzero */
-static void get_previous_history(void)
+static int get_previous_history(void)
{
- if (command_ps[0] != '\0' || state->history[state->cur_history] == NULL) {
- free(state->history[state->cur_history]);
- state->history[state->cur_history] = xstrdup(command_ps);
+ if ((state->flags & DO_HISTORY) && state->cur_history) {
+ save_command_ps_at_cur_history();
+ state->cur_history--;
+ return 1;
}
- state->cur_history--;
+ beep();
+ return 0;
}
static int get_next_history(void)
{
if (state->flags & DO_HISTORY) {
- int ch = state->cur_history;
- if (ch < state->cnt_history) {
- get_previous_history(); /* save the current history line */
- state->cur_history = ch + 1;
- return state->cur_history;
+ if (state->cur_history < state->cnt_history) {
+ save_command_ps_at_cur_history(); /* save the current history line */
+ return ++state->cur_history;
}
}
beep();
@@ -995,6 +1004,7 @@ static void load_history(const char *fro
for (hi = state->cnt_history; hi > 0;) {
hi--;
free(state->history[hi]);
+ state->history[hi] = NULL;
}
for (hi = 0; hi < MAX_HISTORY;) {
@@ -1006,7 +1016,7 @@ static void load_history(const char *fro
l = strlen(hl);
if (l >= MAX_LINELEN)
hl[MAX_LINELEN-1] = '\0';
- if (l == 0 || hl[0] == ' ') {
+ if (l == 0) {
free(hl);
continue;
}
@@ -1043,19 +1053,27 @@ static void remember_in_history(const ch
if (!(state->flags & DO_HISTORY))
return;
-
+ if (str[0] == '\0')
+ return;
i = state->cnt_history;
- free(state->history[MAX_HISTORY]);
- state->history[MAX_HISTORY] = NULL;
- /* After max history, remove the oldest command */
+ /* Don't save dupes */
+ if (i && strcmp(state->history[i-1], str) == 0)
+ return;
+
+ free(state->history[MAX_HISTORY]); /* redundant, paranoia */
+ state->history[MAX_HISTORY] = NULL; /* redundant, paranoia */
+
+ /* If history[] is full, remove the oldest command */
+ /* we need to keep history[MAX_HISTORY] empty, hence >=, not > */
if (i >= MAX_HISTORY) {
free(state->history[0]);
for (i = 0; i < MAX_HISTORY-1; i++)
state->history[i] = state->history[i+1];
+ /* i == MAX_HISTORY-1 */
}
-// Maybe "if (!i || strcmp(history[i-1], command) != 0) ..."
-// (i.e. do not save dups?)
+ /* i <= MAX_HISTORY-1 */
state->history[i++] = xstrdup(str);
+ /* i <= MAX_HISTORY */
state->cur_history = i;
state->cnt_history = i;
#if ENABLE_FEATURE_EDITING_SAVEHISTORY
@@ -1432,6 +1450,13 @@ int FAST_FUNC read_line_input(const char
}
}
#endif
+
+#if 0
+ for (ic = 0; ic <= MAX_HISTORY; ic++)
+ bb_error_msg("history[%d]:'%s'", ic, state->history[ic]);
+ bb_error_msg("cur_history:%d cnt_history:%d", state->cur_history, state->cnt_history);
+#endif
+
/* Print out the command prompt */
parse_and_put_prompt(prompt);
@@ -1540,11 +1565,8 @@ int FAST_FUNC read_line_input(const char
vi_case(CTRL('P')|vbit:)
vi_case('k'|vbit:)
/* Control-p -- Get previous command from history */
- if ((state->flags & DO_HISTORY) && state->cur_history > 0) {
- get_previous_history();
+ if (get_previous_history())
goto rewrite_line;
- }
- beep();
break;
#endif
@@ -1733,10 +1755,8 @@ int FAST_FUNC read_line_input(const char
#if MAX_HISTORY > 0
case 'A':
/* Up Arrow -- Get previous command from history */
- if ((state->flags & DO_HISTORY) && state->cur_history > 0) {
- get_previous_history();
+ if (get_previous_history())
goto rewrite_line;
- }
beep();
break;
case 'B':
@@ -1746,7 +1766,7 @@ int FAST_FUNC read_line_input(const char
rewrite_line:
/* Rewrite the line with the selected history item */
/* change command */
- command_len = strlen(strcpy(command, state->history[state->cur_history]));
+ command_len = strlen(strcpy(command, state->history[state->cur_history] ? : ""));
/* redraw and go to eol (bol, in vi */
redraw(cmdedit_y, (state->flags & VI_MODE) ? 9999 : 0);
break;
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