ftpd: EPSV and SIZE support. Tested to work on IPv6 too.

libbb: str2sockaddr shuld accept [IPv6] addr without port -
 wget 'ftp://[::1]/file' needs that to work.

function                                             old     new   delta
bind_for_passive_mode                                  -     129    +129
get_nport                                              -      30     +30
ftpd_main                                           1731    1760     +29
str2sockaddr                                         412     431     +19
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 2/0 up/down: 207/0)             Total: 207 bytes
   text    data     bss     dec     hex filename
 808568     476    7864  816908   c770c busybox_old
 808804     476    7864  817144   c77f8 busybox_unstripped

1 files changed, 97 insertions, 96 deletions

diff --git a/networking/ftpd.c b/networking/ftpd.c
index b2d6ef2d2..e83066032 100644
--- a/networking/ftpd.c
+++ b/networking/ftpd.c
@@ -4,6 +4,8 @@
  *
  * Author: Adam Tkac <vonsch@gmail.com>
  *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ *
  * Only subset of FTP protocol is implemented but vast majority of clients
  * should not have any problem. You have to run this daemon via inetd.
  *
@@ -32,6 +34,8 @@
 #define FTP_GOODBYE             221
 #define FTP_TRANSFEROK          226
 #define FTP_PASVOK              227
+/*#define FTP_EPRTOK              228*/
+#define FTP_EPSVOK              229
 #define FTP_LOGINOK             230
 #define FTP_CWDOK               250
 #define FTP_RMDIROK             250
@@ -70,6 +74,7 @@ enum {
         const_CDUP = mk_const4('C', 'D', 'U', 'P'),
         const_CWD  = mk_const3('C', 'W', 'D'),
         const_DELE = mk_const4('D', 'E', 'L', 'E'),
+        const_EPSV = mk_const4('E', 'P', 'S', 'V'),
         const_HELP = mk_const4('H', 'E', 'L', 'P'),
         const_LIST = mk_const4('L', 'I', 'S', 'T'),
         const_MKD  = mk_const3('M', 'K', 'D'),
@@ -86,6 +91,7 @@ enum {
         const_RMD  = mk_const3('R', 'M', 'D'),
         const_RNFR = mk_const4('R', 'N', 'F', 'R'),
         const_RNTO = mk_const4('R', 'N', 'T', 'O'),
+        const_SIZE = mk_const4('S', 'I', 'Z', 'E'),
         const_STAT = mk_const4('S', 'T', 'A', 'T'),
         const_STOR = mk_const4('S', 'T', 'O', 'R'),
         const_STOU = mk_const4('S', 'T', 'O', 'U'),
@@ -232,26 +238,11 @@ handle_cdup(void)
         handle_cwd();
 }
 
-//static void
-//handle_type(void)
-//{
-//      if (G.ftp_arg
-//       && (  ((G.ftp_arg[0] | 0x20) == 'i' && G.ftp_arg[1] == '\0')
-//          || !strcasecmp(G.ftp_arg, "L8")
-//          || !strcasecmp(G.ftp_arg, "L 8")
-//          )
-//      ) {
-//              cmdio_write_ok(FTP_TYPEOK);
-//      } else {
-//              cmdio_write_error(FTP_BADCMD);
-//      }
-//}
-
 static void
 handle_stat(void)
 {
         cmdio_write_raw(STR(FTP_STATOK)"-FTP server status:\r\n"
-                        "TYPE: BINARY\r\n"
+                        " TYPE: BINARY\r\n"
                         STR(FTP_STATOK)" Ok\r\n");
 }
 
@@ -259,11 +250,11 @@ static void
 handle_help(void)
 {
         cmdio_write_raw(STR(FTP_HELP)"-Commands:\r\n"
-                        "ALLO CDUP CWD HELP LIST\r\n"
-                        "MODE NLST NOOP PASS PASV PORT PWD QUIT\r\n"
-                        "REST RETR STAT STRU SYST TYPE USER\r\n"
+                        " ALLO CDUP CWD EPSV HELP LIST\r\n"
+                        " MODE NLST NOOP PASS PASV PORT PWD QUIT\r\n"
+                        " REST RETR SIZE STAT STRU SYST TYPE USER\r\n"
 #if ENABLE_FEATURE_FTP_WRITE
-                        "APPE DELE MKD RMD RNFR RNTO STOR STOU\r\n"
+                        " APPE DELE MKD RMD RNFR RNTO STOR STOU\r\n"
 #endif
                         STR(FTP_HELP)" Ok\r\n");
 }
@@ -380,47 +371,57 @@ port_pasv_cleanup(void)
         G.pasv_listen_fd = -1;
 }
 
-static void
-handle_pasv(void)
+static unsigned
+bind_for_passive_mode(void)
 {
-        int bind_retries = 10;
-        unsigned short port;
-        enum { min_port = 1024, max_port = 65535 };
-        char *addr, *response;
+        unsigned port;
 
         port_pasv_cleanup();
 
         G.pasv_listen_fd = xsocket(G.local_addr->u.sa.sa_family, SOCK_STREAM, 0);
         setsockopt_reuseaddr(G.pasv_listen_fd);
 
-        /* TODO bind() with port == 0 and then call getsockname */
-        while (--bind_retries) {
-                port = rand() % max_port;
-                if (port < min_port) {
-                        port += min_port;
-                }
+        set_nport(G.local_addr, 0);
+        xbind(G.pasv_listen_fd, &G.local_addr->u.sa, G.local_addr->len);
+        xlisten(G.pasv_listen_fd, 1);
+        getsockname(G.pasv_listen_fd, &G.local_addr->u.sa, &G.local_addr->len);
 
-                set_nport(G.local_addr, htons(port));
-                /* We don't want to use xbind, it'll die if port is in use */
-                if (bind(G.pasv_listen_fd, &G.local_addr->u.sa, G.local_addr->len) != 0) {
-                        /* do we want check if errno == EADDRINUSE ? */
-                        continue;
-                }
-                xlisten(G.pasv_listen_fd, 1);
-                break;
-        }
+        port = get_nport(&G.local_addr->u.sa);
+        port = ntohs(port);
 
-        if (!bind_retries)
-                bb_error_msg_and_die("can't create pasv socket");
+        return port;
+}
 
-        addr = xmalloc_sockaddr2dotted_noport(&G.local_addr->u.sa);
+static void
+handle_pasv(void)
+{
+        unsigned port;
+        char *addr, *response;
+
+        port = bind_for_passive_mode();
+
+        if (G.local_addr->u.sa.sa_family == AF_INET)
+                addr = xmalloc_sockaddr2dotted_noport(&G.local_addr->u.sa);
+        else /* seen this in the wild done by other ftp servers: */
+                addr = xstrdup("0.0.0.0");
         replace_char(addr, '.', ',');
 
-        response = xasprintf(" Entering Passive Mode (%s,%u,%u)",
+        response = xasprintf(STR(FTP_PASVOK)" Entering Passive Mode (%s,%u,%u)\r\n",
                         addr, (int)(port >> 8), (int)(port & 255));
         free(addr);
+        cmdio_write_raw(response);
+        free(response);
+}
 
-        cmdio_write(FTP_PASVOK, response);
+static void
+handle_epsv(void)
+{
+        unsigned port;
+        char *response;
+
+        port = bind_for_passive_mode();
+        response = xasprintf(STR(FTP_EPSVOK)" EPSV Ok (|||%u|)\r\n", port);
+        cmdio_write_raw(response);
         free(response);
 }
 
@@ -477,7 +478,7 @@ static void
 handle_retr(void)
 {
         struct stat statbuf;
-        int trans_ret, retval;
+        int trans_ret;
         int remote_fd;
         int opened_file;
         off_t offset = G.restart_pos;
@@ -495,8 +496,7 @@ handle_retr(void)
                 return;
         }
 
-        retval = fstat(opened_file, &statbuf);
-        if (retval < 0 || !S_ISREG(statbuf.st_mode)) {
+        if (fstat(opened_file, &statbuf) != 0 || !S_ISREG(statbuf.st_mode)) {
                 /* Note - pretend open failed */
                 cmdio_write_error(FTP_FILEFAIL);
                 goto file_close_out;
@@ -580,10 +580,8 @@ write_filestats(int fd, const char *filename,
         off_t size;
         char *stats, *lnkname = NULL, *perms;
         const char *name;
-        int retval;
         char timestr[32];
         struct tm *tm;
-        const char *format = "%b %d %H:%M";
 
         name = bb_get_last_path_component_nostrip(filename);
 
@@ -595,8 +593,7 @@ write_filestats(int fd, const char *filename,
                         lnkname = xmalloc_readlink(filename);
 
                 tm = gmtime(&statbuf->st_mtime);
-                retval = strftime(timestr, sizeof(timestr), format, tm);
-                if (retval == 0)
+                if (strftime(timestr, sizeof(timestr), "%b %d %H:%M", tm) == 0)
                         bb_error_msg_and_die("strftime");
 
                 timestr[sizeof(timestr) - 1] = '\0';
@@ -719,6 +716,23 @@ handle_stat_file(void)
         handle_dir_common(1, 1);
 }
 
+static void
+handle_size(void)
+{
+        struct stat statbuf;
+        char buf[sizeof(STR(FTP_STATFILE_OK)" %"OFF_FMT"u\r\n") + sizeof(off_t)*3];
+
+        if (!G.ftp_arg
+         || stat(G.ftp_arg, &statbuf) != 0
+         || !S_ISREG(statbuf.st_mode)
+        ) {
+                cmdio_write_error(FTP_FILEFAIL);
+                return;
+        }
+        sprintf(buf, STR(FTP_STATFILE_OK)" %"OFF_FMT"u\r\n", statbuf.st_size);
+        cmdio_write_raw(buf);
+}
+
 /* Upload commands */
 
 #if ENABLE_FEATURE_FTP_WRITE
@@ -1003,63 +1017,52 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
                         cmdio_write_ok(FTP_GOODBYE);
                         return 0;
                 }
-                if (cmdval == const_PWD)
+                else if (cmdval == const_USER)
+                        cmdio_write_ok(FTP_GIVEPWORD);
+                else if (cmdval == const_PASS)
+                        cmdio_write_ok(FTP_LOGINOK);
+                else if (cmdval == const_NOOP)
+                        cmdio_write_ok(FTP_NOOPOK);
+                else if (cmdval == const_TYPE)
+                        cmdio_write_ok(FTP_TYPEOK);
+                else if (cmdval == const_STRU)
+                        cmdio_write_ok(FTP_STRUOK);
+                else if (cmdval == const_MODE)
+                        cmdio_write_ok(FTP_MODEOK);
+                else if (cmdval == const_ALLO)
+                        cmdio_write_ok(FTP_ALLOOK);
+                else if (cmdval == const_SYST)
+                        cmdio_write_raw(STR(FTP_SYSTOK)" UNIX Type: L8\r\n");
+                else if (cmdval == const_PWD)
                         handle_pwd();
                 else if (cmdval == const_CWD)
                         handle_cwd();
                 else if (cmdval == const_CDUP) /* cd .. */
                         handle_cdup();
-                else if (cmdval == const_PASV)
-                        handle_pasv();
-                else if (cmdval == const_RETR)
-                        handle_retr();
-                else if (cmdval == const_NOOP)
-                        cmdio_write_ok(FTP_NOOPOK);
-                else if (cmdval == const_SYST)
-                        cmdio_write_raw(STR(FTP_SYSTOK)" UNIX Type: L8\r\n");
                 else if (cmdval == const_HELP)
                         handle_help();
                 else if (cmdval == const_LIST) /* ls -l */
                         handle_list();
-                else if (cmdval == const_TYPE)
-                        //handle_type();
-                        cmdio_write_ok(FTP_TYPEOK);
-                else if (cmdval == const_PORT)
-                        handle_port();
-                else if (cmdval == const_REST)
-                        handle_rest();
                 else if (cmdval == const_NLST) /* "name list", bare ls */
                         handle_nlst();
-                else if (cmdval == const_STRU) {
-                        //if (G.ftp_arg
-                        // && (G.ftp_arg[0] | 0x20) == 'f'
-                        // && G.ftp_arg[1] == '\0'
-                        //) {
-                                cmdio_write_ok(FTP_STRUOK);
-                        //} else
-                        //      cmdio_write_raw(STR(FTP_BADSTRU)" Bad STRU command\r\n");
-                } else if (cmdval == const_MODE) {
-                        //if (G.ftp_arg
-                        // && (G.ftp_arg[0] | 0x20) == 's'
-                        // && G.ftp_arg[1] == '\0'
-                        //) {
-                                cmdio_write_ok(FTP_MODEOK);
-                        //} else
-                        //      cmdio_write_raw(STR(FTP_BADMODE)" Bad MODE command\r\n");
-                }
-                else if (cmdval == const_ALLO)
-                        cmdio_write_ok(FTP_ALLOOK);
+                else if (cmdval == const_SIZE)
+                        handle_size();
                 else if (cmdval == const_STAT) {
                         if (G.ftp_arg == NULL)
                                 handle_stat();
                         else
                                 handle_stat_file();
-                } else if (cmdval == const_USER) {
-                        /* FTP_LOGINERR confuses clients: */
-                        /* cmdio_write_raw(STR(FTP_LOGINERR)" Can't change to another user\r\n"); */
-                        cmdio_write_ok(FTP_GIVEPWORD);
-                } else if (cmdval == const_PASS)
-                        cmdio_write_ok(FTP_LOGINOK);
+                }
+                else if (cmdval == const_PASV)
+                        handle_pasv();
+                else if (cmdval == const_EPSV)
+                        handle_epsv();
+                else if (cmdval == const_RETR)
+                        handle_retr();
+                else if (cmdval == const_PORT)
+                        handle_port();
+                else if (cmdval == const_REST)
+                        handle_rest();
 #if ENABLE_FEATURE_FTP_WRITE
                 else if (G.opts & OPT_w) {
                         if (cmdval == const_STOR)
@@ -1096,10 +1099,8 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
                 else {
                         /* Which unsupported commands were seen in the wild?
                          * (doesn't necessarily mean "we must support them")
-                         * wget 1.11.4: SIZE - todo
                          * lftp 3.6.3: FEAT - is it useful?
                          *             MDTM - works fine without it anyway
-                         * IPv6-style PASV: "EPSV 2" - todo
                          */
                         cmdio_write_raw(STR(FTP_BADCMD)" Unknown command\r\n");
                 }