--- lbbs/src/io.c	2025/11/17 10:57:23	1.68
+++ lbbs/src/io.c	2025/12/17 03:56:39	1.73
@@ -64,8 +64,8 @@ static int stdout_conv_len = 0;
 static int stdin_conv_offset = 0;
 static int stdout_conv_offset = 0;
 
-static iconv_t stdin_cd = NULL;
-static iconv_t stdout_cd = NULL;
+static iconv_t stdin_cd = (iconv_t)(-1);
+static iconv_t stdout_cd = (iconv_t)(-1);
 
 int io_init(void)
 {
@@ -308,7 +308,9 @@ int iflush(void)
 						ret = ssh_channel_write(SSH_channel, stdout_conv + stdout_conv_offset, (uint32_t)(stdout_conv_len - stdout_conv_offset));
 						if (ret == SSH_ERROR)
 						{
+#ifdef _DEBUG
 							log_error("ssh_channel_write() error: %s\n", ssh_get_error(SSH_session));
+#endif
 							retry = 0;
 							break;
 						}
@@ -392,7 +394,9 @@ int igetch(int timeout)
 		{
 			if (SSH_v2 && ssh_channel_is_closed(SSH_channel))
 			{
+#ifdef _DEBUG
 				log_error("SSH channel is closed\n");
+#endif
 				loop = 0;
 				break;
 			}
@@ -450,7 +454,9 @@ int igetch(int timeout)
 						ret = ssh_channel_read_nonblocking(SSH_channel, stdin_buf + stdin_buf_len, sizeof(stdin_buf) - (uint32_t)stdin_buf_len, 0);
 						if (ret == SSH_ERROR)
 						{
+#ifdef _DEBUG
 							log_error("ssh_channel_read_nonblocking() error: %s\n", ssh_get_error(SSH_session));
+#endif
 							loop = 0;
 							break;
 						}
@@ -1034,6 +1040,7 @@ int io_buf_conv(iconv_t cd, char *p_buf,
 	int ret;
 	int in_control = 0;
 	size_t i = 0;
+	int skip_current = 0;
 
 	if (cd == NULL || p_buf == NULL || p_buf_len == NULL || p_buf_offset == NULL || p_conv == NULL || p_conv_len == NULL)
 	{
@@ -1057,8 +1064,10 @@ int io_buf_conv(iconv_t cd, char *p_buf,
 			}
 		}
 
-		if (in_control)
+		if (in_control || skip_current)
 		{
+			skip_current = 0;
+
 			if (out_bytes <= 0)
 			{
 				log_error("No enough free space in p_conv, conv_len=%d, conv_size=%d\n", *p_conv_len, conv_size);
@@ -1072,7 +1081,7 @@ int io_buf_conv(iconv_t cd, char *p_buf,
 			out_bytes--;
 
 			(*p_buf_offset)++;
-			*p_conv_len = (int)(conv_size - out_bytes);
+			(*p_conv_len)++;
 
 			i++;
 			if (i >= 2)
@@ -1092,7 +1101,7 @@ int io_buf_conv(iconv_t cd, char *p_buf,
 #endif
 				if (p_buf != in_buf)
 				{
-					*p_buf_len = (int)(p_buf + *p_buf_len - in_buf);
+					*p_buf_len -= (int)(in_buf - p_buf);
 					*p_buf_offset = 0;
 					*p_conv_len = (int)(conv_size - out_bytes);
 					memmove(p_buf, in_buf, (size_t)(*p_buf_len));
@@ -1117,27 +1126,41 @@ int io_buf_conv(iconv_t cd, char *p_buf,
 				if (in_bytes == 0)
 				{
 					in_bytes = (size_t)(*p_buf_len - *p_buf_offset);
+#ifdef _DEBUG
+					log_error("Reset in_bytes from 0 to %d\n", in_bytes);
+#endif
 				}
 
-				*out_buf = *in_buf;
-				in_buf++;
-				out_buf++;
-				in_bytes--;
-				out_bytes--;
-
-				continue;
+#ifdef _DEBUG
+				log_error("iconv(in_bytes=%d, out_bytes=%d) error: EILSEQ, in_buf[0]=%d\n",
+						  in_bytes, out_bytes, in_buf[0]);
+#endif
+				skip_current = 1;
+			}
+			else // something strange
+			{
+#ifdef _DEBUG
+				log_error("iconv(in_bytes=%d, out_bytes=%d) error: %d, in_buf[0]=%d\n",
+						  in_bytes, out_bytes, errno, in_buf[0]);
+#endif
+				*p_buf_offset = (int)(in_buf - p_buf);
+				*p_conv_len = (int)(conv_size - out_bytes);
+				skip_current = 1;
 			}
 		}
 		else
 		{
-			*p_buf_len = 0;
-			*p_buf_offset = 0;
+			*p_buf_offset = (int)(in_buf - p_buf);
 			*p_conv_len = (int)(conv_size - out_bytes);
-
-			break;
 		}
 	}
 
+	if (*p_buf_offset >= *p_buf_len)
+	{
+		*p_buf_len = 0;
+		*p_buf_offset = 0;
+	}
+
 	return 0;
 }
 
@@ -1172,6 +1195,7 @@ int io_conv_init(const char *charset)
 	{
 		log_error("iconv_open(%s->%s) error: %d\n", BBS_default_charset, tocode, errno);
 		iconv_close(stdin_cd);
+		stdin_cd = (iconv_t)(-1);
 		return -2;
 	}
 
@@ -1180,15 +1204,15 @@ int io_conv_init(const char *charset)
 
 int io_conv_cleanup(void)
 {
-	if (stdin_cd != NULL)
+	if (stdin_cd != (iconv_t)(-1))
 	{
 		iconv_close(stdin_cd);
-		stdin_cd = NULL;
+		stdin_cd = (iconv_t)(-1);
 	}
-	if (stdout_cd != NULL)
+	if (stdout_cd != (iconv_t)(-1))
 	{
 		iconv_close(stdout_cd);
-		stdout_cd = NULL;
+		stdout_cd = (iconv_t)(-1);
 	}
 
 	return 0;