diff -Naur vsftpd-2.0.6.orig/features.c vsftpd-2.0.6/features.c
--- vsftpd-2.0.6.orig/features.c	2008-02-04 05:03:17.000000000 +0300
+++ vsftpd-2.0.6/features.c	2008-06-17 19:01:27.000000000 +0400
@@ -42,7 +42,15 @@
   vsf_cmdio_write_raw(p_sess, " REST STREAM\r\n");
   vsf_cmdio_write_raw(p_sess, " SIZE\r\n");
   vsf_cmdio_write_raw(p_sess, " TVFS\r\n");
-  vsf_cmdio_write_raw(p_sess, " UTF8\r\n");
+  if (tunable_charset_filter_enable)
+  {
+    vsf_cmdio_write_raw(p_sess, " UTF8 OFF\r\n");
+    vsf_cmdio_write_raw(p_sess, " UTF8 ON\r\n");
+  }
+  else
+  {
+    vsf_cmdio_write_raw(p_sess, " UTF8\r\n");
+  }
   vsf_cmdio_write(p_sess, FTP_FEAT, "End");
 }
 
diff -Naur vsftpd-2.0.6.orig/main.c vsftpd-2.0.6/main.c
--- vsftpd-2.0.6.orig/main.c	2008-02-12 08:22:53.000000000 +0300
+++ vsftpd-2.0.6/main.c	2008-06-17 18:41:50.000000000 +0400
@@ -22,6 +22,7 @@
 #include "tcpwrap.h"
 #include "vsftpver.h"
 #include "ssl.h"
+#include "iconv.h"
 
 /*
  * Forward decls of helper functions
@@ -34,6 +35,7 @@
 int
 main(int argc, const char* argv[])
 {
+  iconv_t cd;
   struct vsf_session the_session =
   {
     /* Control connection */
@@ -106,6 +108,22 @@
     }
     vsf_sysutil_free(p_statbuf);
   }
+  if (tunable_charset_filter_enable == 1)
+  {
+    if ((cd = iconv_open(tunable_charset_client, tunable_charset_server))!=(iconv_t)-1)
+    {
+      iconv_close(cd);
+      tunable_charset_filter_enable=1;
+    }
+      else
+    {
+      tunable_charset_filter_enable = 0;
+    }
+  }
+  /* Save tunable_charset_filter_enable value to protect 
+   * from runtime change when it is disabled 
+   */
+  tunable_charset_filter_config_enable = tunable_charset_filter_enable;
   /* Resolve pasv_address if required */
   if (tunable_pasv_address && tunable_pasv_addr_resolve)
   {
diff -Naur vsftpd-2.0.6.orig/opts.c vsftpd-2.0.6/opts.c
--- vsftpd-2.0.6.orig/opts.c	2008-02-12 06:54:56.000000000 +0300
+++ vsftpd-2.0.6/opts.c	2008-06-17 18:55:48.000000000 +0400
@@ -10,18 +10,52 @@
 #include "ftpcodes.h"
 #include "ftpcmdio.h"
 #include "session.h"
+#include "tunables.h"
 
 void
 handle_opts(struct vsf_session* p_sess)
 {
-  str_upper(&p_sess->ftp_arg_str);
-  if (str_equal_text(&p_sess->ftp_arg_str, "UTF8 ON"))
+  struct mystr opts = INIT_MYSTR;
+  struct mystr prm  = INIT_MYSTR;
+
+  str_copy(&opts, &p_sess->ftp_arg_str);
+  str_upper(&opts);
+  str_split_char(&opts, &prm, ' ');
+
+  if (str_equal_text(&opts, "UTF8"))
   {
-    vsf_cmdio_write(p_sess, FTP_OPTSOK, "Always in UTF8 mode.");
+    if (str_equal_text(&prm, "ON"))
+    {
+      if (tunable_charset_filter_config_enable)
+      {
+        tunable_charset_filter_enable = 0;
+        vsf_cmdio_write(p_sess, FTP_OPTSOK, "UTF8 option is On.");
+      }
+      else
+      {
+        vsf_cmdio_write(p_sess, FTP_OPTSOK, "Always in UTF8 mode.");
+      }
+    }
+    else
+    if (tunable_charset_filter_config_enable)
+    {
+      if (str_equal_text(&prm, "OFF"))
+      {
+        tunable_charset_filter_enable = 1;
+        vsf_cmdio_write(p_sess, FTP_OPTSOK, "UTF8 option is Off.");
+      }
+      else
+      {
+        vsf_cmdio_write(p_sess, FTP_BADOPTS, "Invalid UTF8 option.");
+      }
+    }
+    else
+    {
+      vsf_cmdio_write(p_sess, FTP_BADOPTS, "Option not understood.");
+    }
   }
   else
   {
     vsf_cmdio_write(p_sess, FTP_BADOPTS, "Option not understood.");
   }
 }
-
diff -Naur vsftpd-2.0.6.orig/parseconf.c vsftpd-2.0.6/parseconf.c
--- vsftpd-2.0.6.orig/parseconf.c	2008-02-12 07:53:32.000000000 +0300
+++ vsftpd-2.0.6/parseconf.c	2008-06-17 16:31:51.000000000 +0400
@@ -102,6 +102,7 @@
   { "debug_ssl", &tunable_debug_ssl },
   { "require_cert", &tunable_require_cert },
   { "validate_cert", &tunable_validate_cert },
+  { "charset_filter_enable", &tunable_charset_filter_enable },
   { 0, 0 }
 };
 
@@ -173,6 +174,8 @@
   { "rsa_private_key_file", &tunable_rsa_private_key_file },
   { "dsa_private_key_file", &tunable_dsa_private_key_file },
   { "ca_certs_file", &tunable_ca_certs_file },
+  { "charset_client", &tunable_charset_client },
+  { "charset_server", &tunable_charset_server },
   { 0, 0 }
 };
 
diff -Naur vsftpd-2.0.6.orig/postlogin.c vsftpd-2.0.6/postlogin.c
--- vsftpd-2.0.6.orig/postlogin.c	2008-02-12 06:53:06.000000000 +0300
+++ vsftpd-2.0.6/postlogin.c	2008-06-17 17:15:41.000000000 +0400
@@ -1785,6 +1785,17 @@
     vsf_cmdio_write_raw(p_sess, vsf_sysutil_ulong_to_str(p_sess->num_clients));
     vsf_cmdio_write_raw(p_sess, "\r\n");
   }
+  if (tunable_charset_filter_enable)
+  {
+    vsf_cmdio_write_raw(p_sess, "     Server charset is ");
+    vsf_cmdio_write_raw(p_sess, tunable_charset_server);
+    vsf_cmdio_write_raw(p_sess, "\r\n");
+    vsf_cmdio_write_raw(p_sess, "     Remote charset is ");
+    vsf_cmdio_write_raw(p_sess, tunable_charset_client);
+    vsf_cmdio_write_raw(p_sess, "\r\n");
+    vsf_cmdio_write_raw(p_sess, "     Use OPTS UTF8 ON to enable UTF8!!");
+    vsf_cmdio_write_raw(p_sess, "\r\n");
+  }
   vsf_cmdio_write_raw(p_sess,
     "     vsFTPd " VSF_VERSION " - secure, fast, stable\r\n");
   vsf_cmdio_write(p_sess, FTP_STATOK, "End of status");
diff -Naur vsftpd-2.0.6.orig/readwrite.c vsftpd-2.0.6/readwrite.c
--- vsftpd-2.0.6.orig/readwrite.c	2008-02-02 04:30:40.000000000 +0300
+++ vsftpd-2.0.6/readwrite.c	2008-06-17 16:31:51.000000000 +0400
@@ -15,11 +15,17 @@
 #include "privsock.h"
 #include "defs.h"
 #include "sysutil.h"
+#include "str.h"
+#include "tunables.h"
 
 int
 ftp_write_str(const struct vsf_session* p_sess, const struct mystr* p_str,
               enum EVSFRWTarget target)
 {
+  if(tunable_charset_filter_enable)
+  {
+    str_iconv_write(p_str);
+  }
   if (target == kVSFRWData)
   {
     if (p_sess->data_use_ssl)
@@ -94,5 +100,9 @@
     str_netfd_alloc(
       p_str, VSFTP_COMMAND_FD, '\n', p_buf, VSFTP_MAX_COMMAND_LINE);
   }
+  if(tunable_charset_filter_enable)
+  {
+    str_iconv_read(p_str);
+  }
 }
 
diff -Naur vsftpd-2.0.6.orig/str.c vsftpd-2.0.6/str.c
--- vsftpd-2.0.6.orig/str.c	2008-02-02 04:30:39.000000000 +0300
+++ vsftpd-2.0.6/str.c	2008-06-17 16:31:51.000000000 +0400
@@ -19,6 +19,13 @@
 /* Ick. Its for die() */
 #include "utility.h"
 #include "sysutil.h"
+#include "stdio.h"
+#include "errno.h"
+#include "tunables.h"
+
+/* For iconv read and write */
+#define ICONV_READ 0
+#define ICONV_WRITE 1
 
 /* File local functions */
 static void str_split_text_common(struct mystr* p_src, struct mystr* p_rhs,
@@ -666,3 +673,102 @@
   }
 }
 
+void
+str_iconv_inout(struct mystr* p_str, char io_direction)
+{
+  iconv_t cd;
+  char *from_buf;
+  char *dyn_from_buf, *to_buf, *dyn_to_buf;
+  size_t from_len;
+  size_t dyn_from_len, to_len, dyn_to_len;
+  size_t print_buf;
+
+  from_buf = str_getbuf(p_str);
+  from_len = str_getlen(p_str);
+
+  p_str->p_buf = 0;
+  str_free(p_str);
+
+  private_str_alloc_memchunk(p_str, from_buf, from_len);
+  str_reserve(p_str, 2*from_len);
+  p_str->len=2*from_len;
+  vsf_sysutil_memclr(p_str->p_buf, p_str->len+1);
+  dyn_from_buf = from_buf;
+  dyn_from_len = from_len;
+  to_buf = p_str->p_buf;
+  dyn_to_buf = to_buf;
+  to_len = p_str->len;
+  dyn_to_len = to_len;
+
+  if(io_direction == ICONV_READ)
+  {
+    if((cd = vsf_sysutil_iconv_init_read())==(iconv_t)(-1))
+    {
+      bug("str_iconv_read");
+    }
+  }
+  else
+  {
+    if((cd = vsf_sysutil_iconv_init_write())==(iconv_t)(-1))
+    {
+      bug("str_iconv_write");
+    }
+  }
+
+  while(vsf_sysutil_iconv(cd, &dyn_from_buf, &dyn_from_len, &dyn_to_buf, &dyn_to_len)==(size_t)(-1))
+  {
+    switch(errno)
+    {
+    case EILSEQ:
+      if((dyn_to_buf<to_buf+to_len)&&(dyn_to_buf>=to_buf))
+      {
+        vsf_sysutil_memcpy(dyn_to_buf, dyn_from_buf, 1);
+        dyn_to_buf+=1;
+        dyn_to_len-=1;
+        dyn_from_buf+=1;
+        dyn_from_len = from_buf + from_len -dyn_from_buf;
+        if(dyn_from_len==0) break;
+      }
+      else
+      {
+        break;
+      }
+      continue;
+
+    case EINVAL:
+      break;
+
+    case E2BIG:
+      str_reserve(p_str, to_len+dyn_from_len);
+      p_str->len=to_len+dyn_from_len;
+      dyn_to_len+=dyn_from_len;
+      dyn_to_buf = p_str->p_buf + (dyn_to_buf-to_buf);
+      to_buf = p_str->p_buf;
+      to_len = p_str->len;
+      continue;
+
+    default:
+      die("iconv set strange errno. Should not happenned!");
+      break;
+    }
+    break;
+  }
+
+  str_trunc(p_str, (p_str->len)-dyn_to_len);
+
+  vsf_sysutil_iconv_close(cd);
+  vsf_sysutil_free(from_buf);
+}
+
+void
+str_iconv_read(struct mystr* p_str)
+{
+  str_iconv_inout(p_str, ICONV_READ);
+}
+
+void
+str_iconv_write(struct mystr* p_str)
+{
+  str_iconv_inout(p_str, ICONV_WRITE);
+}
+
diff -Naur vsftpd-2.0.6.orig/str.h vsftpd-2.0.6/str.h
--- vsftpd-2.0.6.orig/str.h	2008-02-02 04:30:40.000000000 +0300
+++ vsftpd-2.0.6/str.h	2008-06-17 16:31:51.000000000 +0400
@@ -120,5 +120,9 @@
 int str_contains_line(const struct mystr* p_str,
                       const struct mystr* p_line_str);
 
+/* Locale string conversion */
+void str_iconv_read(struct mystr* p_str);
+void str_iconv_write(struct mystr* p_str);
+
 #endif /* VSFTP_STR_H */
 
diff -Naur vsftpd-2.0.6.orig/sysutil.c vsftpd-2.0.6/sysutil.c
--- vsftpd-2.0.6.orig/sysutil.c	2008-02-02 04:30:41.000000000 +0300
+++ vsftpd-2.0.6/sysutil.c	2008-06-17 16:31:51.000000000 +0400
@@ -53,6 +53,7 @@
 #include <syslog.h>
 #include <utime.h>
 #include <netdb.h>
+#include <iconv.h>
 
 /* Private variables to this file */
 /* Current umask() */
@@ -2650,3 +2651,63 @@
   return utime(p_file, &new_times);
 }
 
+iconv_t
+vsf_sysutil_iconv_init_read(void)
+{
+  iconv_t cd;
+
+  if((cd=iconv_open(tunable_charset_server, tunable_charset_client))==(iconv_t)(-1))
+  {
+    if(errno==EINVAL)
+    {
+      vsf_sysutil_free(tunable_charset_server);
+      tunable_charset_server=vsf_sysutil_strdup("UTF8");
+      vsf_sysutil_free(tunable_charset_client);
+      tunable_charset_client=vsf_sysutil_strdup("UTF8");
+      return iconv_open(tunable_charset_server, tunable_charset_client);
+    }
+    else
+    {
+      bug("iconv_open error!");
+    }
+  }
+
+  return cd;
+}
+
+iconv_t
+vsf_sysutil_iconv_init_write(void)
+{
+  iconv_t cd;
+
+  if((cd=iconv_open(tunable_charset_client, tunable_charset_server))==(iconv_t)(-1))
+  {
+    if(errno==EINVAL)
+    {
+      vsf_sysutil_free(tunable_charset_server);
+      tunable_charset_server=vsf_sysutil_strdup("UTF8");
+      vsf_sysutil_free(tunable_charset_client);
+      tunable_charset_client=vsf_sysutil_strdup("UTF8");
+      return iconv_open(tunable_charset_server, tunable_charset_client);
+    }
+    else
+    {
+      bug("iconv_open error!");
+    }
+  }
+  return cd;
+}
+
+int
+vsf_sysutil_iconv_close(iconv_t cd)
+{
+  return iconv_close(cd);
+}
+
+
+size_t
+vsf_sysutil_iconv(iconv_t cd, char **inbuf, size_t *inbytes, char **outbuf, size_t *outbytes)
+{
+  return iconv(cd, inbuf, inbytes, outbuf, outbytes);
+}
+
diff -Naur vsftpd-2.0.6.orig/sysutil.h vsftpd-2.0.6/sysutil.h
--- vsftpd-2.0.6.orig/sysutil.h	2008-02-02 04:30:39.000000000 +0300
+++ vsftpd-2.0.6/sysutil.h	2008-06-17 16:31:51.000000000 +0400
@@ -7,6 +7,14 @@
 #include "filesize.h"
 #endif
 
+#ifndef VSF_SYSUTIL_ICONV_H
+#include "iconv.h"
+#endif
+
+#ifndef VSF_SYSUTIL_STDDEF_H
+#include "stddef.h"
+#endif
+
 /* Return value queries */
 int vsf_sysutil_retval_is_error(int retval);
 enum EVSFSysUtilError
@@ -330,5 +338,12 @@
 void vsf_sysutil_sleep(double seconds);
 int vsf_sysutil_setmodtime(const char* p_file, long the_time, int is_localtime);
 
+/* Locale string conversion */
+
+iconv_t vsf_sysutil_iconv_init_read(void);
+iconv_t vsf_sysutil_iconv_init_write(void);
+int vsf_sysutil_iconv_close(iconv_t cd);
+size_t vsf_sysutil_iconv(iconv_t cd, char **inbuf, size_t *inbytes, char **outbuf, size_t *outbytes);
+
 #endif /* VSF_SYSUTIL_H */
 
diff -Naur vsftpd-2.0.6.orig/tunables.c vsftpd-2.0.6/tunables.c
--- vsftpd-2.0.6.orig/tunables.c	2008-02-12 07:53:01.000000000 +0300
+++ vsftpd-2.0.6/tunables.c	2008-06-17 18:38:46.000000000 +0400
@@ -68,6 +68,8 @@
 int tunable_tilde_user_enable = 0;
 int tunable_force_anon_logins_ssl = 0;
 int tunable_force_anon_data_ssl = 0;
+int tunable_charset_filter_enable = 0;
+int tunable_charset_filter_config_enable = 0;
 int tunable_mdtm_write = 1;
 int tunable_lock_upload_files = 1;
 int tunable_pasv_addr_resolve = 0;
@@ -131,4 +133,6 @@
 const char* tunable_rsa_private_key_file = 0;
 const char* tunable_dsa_private_key_file = 0;
 const char* tunable_ca_certs_file = 0;
+const char* tunable_charset_client = "UTF-8";
+const char* tunable_charset_server = "UTF-8";
 
diff -Naur vsftpd-2.0.6.orig/tunables.h vsftpd-2.0.6/tunables.h
--- vsftpd-2.0.6.orig/tunables.h	2008-02-12 07:52:49.000000000 +0300
+++ vsftpd-2.0.6/tunables.h	2008-06-17 18:39:55.000000000 +0400
@@ -64,6 +64,8 @@
 extern int tunable_tilde_user_enable;         /* Support e.g. ~chris */
 extern int tunable_force_anon_logins_ssl;     /* Require anon logins use SSL */
 extern int tunable_force_anon_data_ssl;       /* Require anon data uses SSL */
+extern int tunable_charset_filter_enable;     /* Enable charset transfer (may be changed at runtime if config allows) */
+extern int tunable_charset_filter_config_enable; /* Is charset transfer enabled at config? */
 extern int tunable_mdtm_write;                /* Allow MDTM to set timestamps */
 extern int tunable_lock_upload_files;         /* Lock uploading files */
 extern int tunable_pasv_addr_resolve;         /* DNS resolve pasv_addr */
@@ -125,6 +127,8 @@
 extern const char* tunable_rsa_private_key_file;
 extern const char* tunable_dsa_private_key_file;
 extern const char* tunable_ca_certs_file;
+extern const char* tunable_charset_client;
+extern const char* tunable_charset_server;
 
 #endif /* VSF_TUNABLES_H */
 
diff -Naur vsftpd-2.0.6.orig/vsftpd.conf.5 vsftpd-2.0.6/vsftpd.conf.5
--- vsftpd-2.0.6.orig/vsftpd.conf.5	2008-02-12 07:56:32.000000000 +0300
+++ vsftpd-2.0.6/vsftpd.conf.5	2008-06-17 17:04:14.000000000 +0400
@@ -112,6 +112,17 @@
 
 Default: NO
 .TP
+.B charset_filter_enable
+When enabled, vsftpd will setup a character set filter. This filter will be
+disabled per client on OPTS UTF8 ON request and may be enabled again with
+OPTS UTF8 OFF.
+.B Warning!
+This option brokes RFC2640 (FTP i18n), but it seems to be the only way to
+support dumb non-UTF8 clients. It is not recommended because it depends on the
+implementation of external glibc library. vsftpd can't ensure the security.
+
+Default: NO
+.TP
 .B check_shell
 Note! This option only has an effect for non-PAM builds of vsftpd. If disabled,
 vsftpd will not check /etc/shells for a valid user shell for local logins.
@@ -591,8 +602,9 @@
 Default: 0 (unlimited)
 .TP
 .B anon_umask
-The value that the umask for file creation is set to for anonymous users. NOTE! If you want to specify octal values, remember the "0" prefix otherwise the
-value will be treated as a base 10 integer!
+The value that the umask for file creation is set to for anonymous users.
+NOTE! If you want to specify octal values, remember the "0" prefix otherwise
+the value will be treated as a base 10 integer!
 
 Default: 077
 .TP
@@ -736,6 +748,20 @@
 
 Default: (none)
 .TP
+.B charset_client
+For this option to take effect,
+.BR charset_filter_enable 
+must be set. This option set the character set for client side.
+
+Default: UTF-8
+.TP
+.B charset_server
+For this option to take effect,
+.BR charset_filter_enable 
+must be set. This option set the character set for server side.
+
+Default: UTF-8
+.TP
 .B chown_username
 This is the name of the user who is given ownership of anonymously uploaded
 files. This option is only relevant if another option,
@@ -997,4 +1023,5 @@
 
 .SH AUTHOR
 scarybeasts@gmail.com
+wzhou@princeton.edu