1 files changed, 47 insertions, 26 deletions

diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index fb595c010..b3f4f5327 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -953,24 +953,33 @@ static void input_tab(smallint *lastWasTab)
 
 #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();
@@ -992,6 +1001,7 @@ static void load_history(const char *fromfile)
                 for (hi = state->cnt_history; hi > 0;) {
                         hi--;
                         free(state->history[hi]);
+                        state->history[hi] = NULL;
                 }
 
                 for (hi = 0; hi < MAX_HISTORY;) {
@@ -1003,14 +1013,14 @@ static void load_history(const char *fromfile)
                         l = strlen(hl);
                         if (l >= MAX_LINELEN)
                                 hl[MAX_LINELEN-1] = '\0';
-                        if (l == 0 || hl[0] == ' ') {
+                        if (l == 0) {
                                 free(hl);
                                 continue;
                         }
                         state->history[hi++] = hl;
                 }
                 fclose(fp);
-                state->cur_history = state->cnt_history = hi;
+                state->cnt_history = hi;
         }
 }
 
@@ -1040,19 +1050,27 @@ static void remember_in_history(const char *str)
 
         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
@@ -1394,6 +1412,7 @@ int read_line_input(const char *prompt, char *command, int maxsize, line_input_t
         if ((state->flags & SAVE_HISTORY) && state->hist_file)
                 load_history(state->hist_file);
 #endif
+        state->cur_history = state->cnt_history;
 
         /* prepare before init handlers */
         cmdedit_y = 0;  /* quasireal y, not true if line > xt*yt */
@@ -1429,6 +1448,13 @@ int read_line_input(const char *prompt, char *command, int maxsize, line_input_t
                 }
         }
 #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);
 
@@ -1537,11 +1563,8 @@ int read_line_input(const char *prompt, char *command, int maxsize, line_input_t
                 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
 
@@ -1730,10 +1753,8 @@ int read_line_input(const char *prompt, char *command, int maxsize, line_input_t
 #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':
@@ -1743,7 +1764,7 @@ int read_line_input(const char *prompt, char *command, int maxsize, line_input_t
  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;