--- lbbs/src/screen.c	2025/05/30 00:20:53	1.80
+++ lbbs/src/screen.c	2025/06/01 14:32:41	1.87
@@ -231,11 +231,13 @@ int get_data(int row, int col, char *pro
 	return len;
 }
 
-int display_data(const void *p_data, long line_total, const long *p_line_offsets, int begin_line, int wait)
+int display_data(const void *p_data, long line_total, const long *p_line_offsets, int begin_line, int eof_exit,
+				 display_data_key_handler key_handler, const char *help_filename)
 {
 	static int show_help = 1;
 	char buffer[LINE_BUFFER_LEN];
-	int ch = KEY_NULL;
+	DISPLAY_CTX ctx;
+	int ch = 0;
 	int input_ok, line, max_lines;
 	long int line_current = 0;
 	long int len;
@@ -247,16 +249,22 @@ int display_data(const void *p_data, lon
 	line = begin_line;
 	max_lines = SCREEN_ROWS - 1;
 
+	// update msg_ext with extended key handler
+	if (key_handler(&ch, &ctx) != 0)
+	{
+		return ch;
+	}
+
 	loop = 1;
 	while (!SYS_server_exit && loop)
 	{
-		if (line_current >= line_total && line_total <= SCREEN_ROWS - 2)
+		if (eof_exit > 0 && line_current >= line_total && line_total <= SCREEN_ROWS - 2)
 		{
-			if (wait)
+			if (eof_exit == 1)
 			{
 				ch = press_any_key();
 			}
-			else
+			else // if (eof_exit == 2)
 			{
 				iflush();
 			}
@@ -267,25 +275,31 @@ int display_data(const void *p_data, lon
 
 		if (line_current >= line_total || line >= max_lines)
 		{
+			ctx.reach_begin = (line_current < line ? 1 : 0);
+
 			if (line_current - (line - 1) + (SCREEN_ROWS - 2) < line_total)
 			{
 				percentile = (line_current - (line - 1) + (SCREEN_ROWS - 2)) * 100 / line_total;
+				ctx.reach_end = 0;
 			}
 			else
 			{
 				percentile = 100;
+				ctx.reach_end = 1;
 			}
 
+			ctx.line_top = line_current - (line - 1) + 1;
+			ctx.line_bottom = MIN(line_current - (line - 1) + (SCREEN_ROWS - 2), line_total);
+
 			snprintf(buffer, sizeof(buffer),
-					 "\033[1;44;33m第\033[32m%ld\033[33m-\033[32m%ld\033[33m行 (\033[32m%ld%%\033[33m) │ "
-					 "返回[\033[32m←\033[33m,\033[32mESC\033[33m] │ 移动[\033[32m↑\033[33m/\033[32m↓\033[33m/\033[32mPgUp\033[33m/\033[32mPgDn\033[33m] │ "
-					 "帮助[\033[32mh\033[33m] │",
-					 line_current - (line - 1) + 1,
-					 MIN(line_current - (line - 1) + (SCREEN_ROWS - 2), line_total),
-					 percentile);
+					 "\033[1;44;33m第\033[32m%ld\033[33m-\033[32m%ld\033[33m行 (\033[32m%ld%%\033[33m) %s",
+					 ctx.line_top,
+					 ctx.line_bottom,
+					 percentile,
+					 ctx.msg);
 
 			len = split_line(buffer, SCREEN_COLS, &eol, &display_len);
-			for (;display_len < SCREEN_COLS; display_len++)
+			for (; display_len < SCREEN_COLS; display_len++)
 			{
 				buffer[len++] = ' ';
 			}
@@ -301,25 +315,40 @@ int display_data(const void *p_data, lon
 			{
 				ch = igetch_t(MAX_DELAY_TIME);
 				input_ok = 1;
+
+				// extended key handler
+				if (key_handler(&ch, &ctx) != 0)
+				{
+					goto cleanup;
+				}
+
 				switch (ch)
 				{
 				case KEY_NULL:
 				case KEY_TIMEOUT:
 					goto cleanup;
 				case KEY_HOME:
+					if (line_current - line < 0) // Reach begin
+					{
+						break;
+					}
 					line_current = 0;
 					line = begin_line;
 					max_lines = SCREEN_ROWS - 1;
 					clrline(begin_line, SCREEN_ROWS);
 					break;
 				case KEY_END:
+					if (line_total < SCREEN_ROWS - 2)
+					{
+						break;
+					}
 					line_current = line_total - (SCREEN_ROWS - 2);
 					line = begin_line;
 					max_lines = SCREEN_ROWS - 1;
 					clrline(begin_line, SCREEN_ROWS);
 					break;
 				case KEY_UP:
-					if (line_current - line < 0) // Reach top
+					if (line_current - line < 0) // Reach begin
 					{
 						break;
 					}
@@ -333,7 +362,7 @@ int display_data(const void *p_data, lon
 					igetch_reset();
 				case KEY_SPACE:
 				case KEY_DOWN:
-					if (line_current + ((SCREEN_ROWS - 2) - (line - 1)) >= line_total) // Reach bottom
+					if (line_current + ((SCREEN_ROWS - 2) - (line - 1)) >= line_total) // Reach end
 					{
 						break;
 					}
@@ -345,7 +374,7 @@ int display_data(const void *p_data, lon
 					prints("\033[S"); // Scroll up 1 line
 					break;
 				case KEY_PGUP:
-					if (line_current - line < 0) // Reach top
+					if (line_current - line < 0) // Reach begin
 					{
 						break;
 					}
@@ -359,7 +388,7 @@ int display_data(const void *p_data, lon
 					clrline(begin_line, SCREEN_ROWS);
 					break;
 				case KEY_PGDN:
-					if (line_current + (SCREEN_ROWS - 2) - (line - 1) >= line_total) // Reach bottom
+					if (line_current + (SCREEN_ROWS - 2) - (line - 1) >= line_total) // Reach end
 					{
 						break;
 					}
@@ -377,22 +406,24 @@ int display_data(const void *p_data, lon
 					loop = 0;
 					break;
 				case 'h':
-					if (!show_help)
+					if (!show_help) // Not reentrant
 					{
 						break;
 					}
 
 					// Display help information
 					show_help = 0;
-					display_file(DATA_READ_HELP, begin_line, 1);
+					display_file(help_filename, begin_line, 1);
 					show_help = 1;
-
+				case KEY_F5:
 					// Refresh after display help information
 					line_current -= (line - 1);
 					line = begin_line;
 					max_lines = SCREEN_ROWS - 1;
 					clrline(begin_line, SCREEN_ROWS);
 					break;
+				case 0: // Refresh bottom line
+					break;
 				default:
 					input_ok = 0;
 					break;
@@ -407,10 +438,16 @@ int display_data(const void *p_data, lon
 		len = p_line_offsets[line_current + 1] - p_line_offsets[line_current];
 		if (len >= LINE_BUFFER_LEN)
 		{
-			log_error("buffer overflow: len=%ld(%ld - %ld) line=%ld \n",
+			log_error("Buffer overflow: len=%ld(%ld - %ld) line=%ld \n",
 					  len, p_line_offsets[line_current + 1], p_line_offsets[line_current], line_current);
 			len = LINE_BUFFER_LEN - 1;
 		}
+		else if (len < 0)
+		{
+			log_error("Incorrect line offsets: len=%ld(%ld - %ld) line=%ld \n",
+					  len, p_line_offsets[line_current + 1], p_line_offsets[line_current], line_current);
+			len = 0;
+		}
 
 		memcpy(buffer, (const char *)p_data + p_line_offsets[line_current], (size_t)len);
 		buffer[len] = '\0';
@@ -426,9 +463,24 @@ cleanup:
 	return ch;
 }
 
-int display_file(const char *filename, int begin_line, int wait)
+static int display_file_key_handler(int *p_key, DISPLAY_CTX *p_ctx)
 {
-	int ch = KEY_NULL;
+	switch (*p_key)
+	{
+	case 0: // Set msg
+		snprintf(p_ctx->msg, sizeof(p_ctx->msg),
+				 "| 返回[\033[32m←\033[33m,\033[32mESC\033[33m] | "
+				 "移动[\033[32m↑\033[33m/\033[32m↓\033[33m/\033[32mPgUp\033[33m/\033[32mPgDn\033[33m] | "
+				 "帮助[\033[32mh\033[33m] |");
+		break;
+	}
+
+	return 0;
+}
+
+int display_file(const char *filename, int begin_line, int eof_exit)
+{
+	int ret;
 	const void *p_shm;
 	size_t data_len;
 	long line_total;
@@ -441,14 +493,14 @@ int display_file(const char *filename, i
 		return KEY_NULL;
 	}
 
-	ch = display_data(p_data, line_total, p_line_offsets, begin_line, wait);
+	ret = display_data(p_data, line_total, p_line_offsets, begin_line, eof_exit, display_file_key_handler, DATA_READ_HELP);
 
 	if (detach_file_shm(p_shm) < 0)
 	{
 		log_error("detach_file_shm(%s) error\n", filename);
 	}
 
-	return ch;
+	return ret;
 }
 
 int show_top(const char *str_left, const char *str_middle, const char *str_right)