/* Basic FTP routines.
   Copyright (C) 1995, 1996, 1997, 1998, 2000 Free Software Foundation, Inc.

This file is part of GNU Wget.

GNU Wget is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

GNU Wget is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Wget; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>

#ifdef HAVE_STRING_H
# include <string.h>
#else
# include <strings.h>
#endif
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <sys/types.h>

/* For inet_ntop. */
#ifndef WINDOWS
#include <sys/socket.h>
#include <arpa/inet.h>
#endif

#ifdef WINDOWS
# include <winsock.h>
#endif

#include "wget.h"
#include "utils.h"
#include "rbuf.h"
#include "connect.h"
#include "host.h"
#include "ftp.h"

char ftp_last_respline[128];


/* Get the response of FTP server and allocate enough room to handle
   it.  <CR> and <LF> characters are stripped from the line, and the
   line is 0-terminated.  All the response lines but the last one are
   skipped.  The last line is determined as described in RFC959.  */
uerr_t
ftp_response (struct rbuf *rbuf, char **line)
{
  int i;
  int bufsize = 40;

  *line = (char *)xmalloc (bufsize);
  do
    {
      for (i = 0; 1; i++)
        {
          int res;
          if (i > bufsize - 1)
            *line = (char *)xrealloc (*line, (bufsize <<= 1));
          res = RBUF_READCHAR (rbuf, *line + i);
          /* RES is number of bytes read.  */
          if (res == 1)
            {
              if ((*line)[i] == '\n')
                {
                  (*line)[i] = '\0';
                  /* Get rid of \r.  */
                  if (i > 0 && (*line)[i - 1] == '\r')
                    (*line)[i - 1] = '\0';
                  break;
                }
            }
          else
            return FTPRERR;
        }
      if (opt.server_response)
        logprintf (LOG_ALWAYS, "%s\n", *line);
      else
        DEBUGP (("%s\n", *line));
    }
  while (!(i >= 3 && ISDIGIT (**line) && ISDIGIT ((*line)[1]) &&
           ISDIGIT ((*line)[2]) && (*line)[3] == ' '));
  strncpy (ftp_last_respline, *line, sizeof (ftp_last_respline));
  ftp_last_respline[sizeof (ftp_last_respline) - 1] = '\0';
  return FTPOK;
}

/* Returns the malloc-ed FTP request, ending with <CR><LF>, printing
   it if printing is required.  If VALUE is NULL, just use
   command<CR><LF>.  */
static char *
ftp_request (const char *command, const char *value)
{
  char *res = (char *)xmalloc (strlen (command)
                               + (value ? (1 + strlen (value)) : 0)
                               + 2 + 1);
  sprintf (res, "%s%s%s\r\n", command, value ? " " : "", value ? value : "");
  if (opt.server_response)
    {
      /* Hack: don't print out password.  */
      if (strncmp (res, "PASS", 4) != 0)
        logprintf (LOG_ALWAYS, "--> %s\n", res);
      else
        logputs (LOG_ALWAYS, "--> PASS Turtle Power!\n");
    }
  else
    DEBUGP (("\n--> %s\n", res));
  return res;
}

#ifdef USE_OPIE
const char *calculate_skey_response PARAMS ((int, const char *, const char *));
#endif

/* Sends the USER and PASS commands to the server, to control
   connection socket csock.  */
uerr_t
ftp_login (struct rbuf *rbuf, const char *acc, const char *pass)
{
  uerr_t err;
  char *request, *respline;
  int nwritten;

  /* Get greeting.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline != '2')
    {
      xfree (respline);
      return FTPSRVERR;
    }
  xfree (respline);
  /* Send USER username.  */
  request = ftp_request ("USER", acc);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  /* An unprobable possibility of logging without a password.  */
  if (*respline == '2')
    {
      xfree (respline);
      return FTPOK;
    }
  /* Else, only response 3 is appropriate.  */
  if (*respline != '3')
    {
      xfree (respline);
      return FTPLOGREFUSED;
    }
#ifdef USE_OPIE
  {
    static const char *skey_head[] = {
      "331 s/key ",
      "331 opiekey "
    };
    int i;

    for (i = 0; i < ARRAY_SIZE (skey_head); i++)
      {
        if (strncasecmp (skey_head[i], respline, strlen (skey_head[i])) == 0)
          break;
      }
    if (i < ARRAY_SIZE (skey_head))
      {
        const char *cp;
        int skey_sequence = 0;

        for (cp = respline + strlen (skey_head[i]);
             '0' <= *cp && *cp <= '9';
             cp++)
          {
            skey_sequence = skey_sequence * 10 + *cp - '0';
          }
        if (*cp == ' ')
          cp++;
        else
          {
          bad:
            xfree (respline);
            return FTPLOGREFUSED;
          }
        if ((cp = calculate_skey_response (skey_sequence, cp, pass)) == 0)
          goto bad;
        pass = cp;
      }
  }
#endif /* USE_OPIE */
  xfree (respline);
  /* Send PASS password.  */
  request = ftp_request ("PASS", pass);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline != '2')
    {
      xfree (respline);
      return FTPLOGINC;
    }
  xfree (respline);
  /* All OK.  */
  return FTPOK;
}

#ifdef INET6
uerr_t
ftp_eprt (struct rbuf *rbuf)
{
  uerr_t err;

  char *request, *respline;
  ip_address in_addr;
  unsigned short port;

  char ipv6 [8 * (4 * 3 + 3) + 8];
  char *bytes;

  /* Setting port to 0 lets the system choose a free port.  */
  port = 0;
  err = bindport (&port, ip_default_family);
  if (err != BINDOK)	/* Bind the port.  */
    return err;

  /* Get the address of this side of the connection.  */
  if (!conaddr (RBUF_FD (rbuf), &in_addr))
    /* Huh?  This is not BINDERR! */
    return BINDERR;
  inet_ntop (AF_INET6, &in_addr, ipv6, sizeof (ipv6));

  /* Construct the argument of EPRT (of the form |2|IPv6.ascii|PORT.ascii|). */
  bytes = alloca (3 + strlen (ipv6) + 1 + numdigit (port) + 1 + 1);
  sprintf (bytes, "|2|%s|%u|", ipv6, port);
  /* Send PORT request.  */
  request = ftp_request ("EPRT", bytes);
  if (0 > iwrite (RBUF_FD (rbuf), request, strlen (request)))
    {
      closeport (port);
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      closeport (port);
      xfree (respline);
      return err;
    }
  if (*respline != '2')
    {
      closeport (port);
      xfree (respline);
      return FTPPORTERR;
    }
  xfree (respline);
  return FTPOK;
}
#endif

/* Bind a port and send the appropriate PORT command to the FTP
   server.  Use acceptport after RETR, to get the socket of data
   connection.  */
uerr_t
ftp_port (struct rbuf *rbuf)
{
  uerr_t err;
  char *request, *respline;
  char bytes[6 * 4 +1];

  ip_address in_addr;
  ip4_address in_addr_4;
  unsigned char *in_addr4_ptr = (unsigned char *)&in_addr_4;

  int nwritten;
  unsigned short port;
#ifdef INET6
  /*
    Only try the Extented Version if we actually use IPv6
  */
  if (ip_default_family == AF_INET6)
    {
      err = ftp_eprt (rbuf);
      if (err == FTPOK)
	return err;
    }
#endif
  /* Setting port to 0 lets the system choose a free port.  */
  port = 0;

  err = bindport (&port, AF_INET);
  if (err != BINDOK)
    return err;

  /* Get the address of this side of the connection and convert it
     (back) to IPv4.  */
  if (!conaddr (RBUF_FD (rbuf), &in_addr))
    /* Huh?  This is not BINDERR! */
    return BINDERR;
  if (!map_ip_to_ipv4 (&in_addr, &in_addr_4))
    return BINDERR;

  /* Construct the argument of PORT (of the form a,b,c,d,e,f).  Port
     is unsigned short so (unsigned) (port & 0xff000) >> 8 is the same
     like port >> 8
   */
  sprintf (bytes, "%d,%d,%d,%d,%d,%d",
	   in_addr4_ptr[0], in_addr4_ptr[1], in_addr4_ptr[2], in_addr4_ptr[3],
	   port >> 8, port & 0xff);
  /* Send PORT request.  */
  request = ftp_request ("PORT", bytes);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline != '2')
    {
      xfree (respline);
      return FTPPORTERR;
    }
  xfree (respline);
  return FTPOK;
}

#ifdef INET6
uerr_t
ftp_epsv (struct rbuf *rbuf, ip_address *addr, unsigned short *port, 
	  char *typ)
{
  int err;
  char *s, *respline;
  char *request = ftp_request ("EPSV", typ);
  if (0 > iwrite (RBUF_FD (rbuf), request, strlen (request)))
    {
      xfree (request);
      return WRITEFAILED;
    }
  /* Get the server response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline != '2')
    {
      xfree (respline);
      return FTPNOPASV;
    }
  /* Parse the request.  */
  s = respline;
  /* respline::=229 Entering Extended Passive Mode (|||6446|) */
  for (s += 4; *s && !ISDIGIT (*s); s++);
  if (!*s)
    return FTPINVPASV;
  *port=0; 
  for (; ISDIGIT (*s); s++) 
    *port = (*s - '0') + 10 * (*port);
  xfree (respline);
  /* Now we have the port but we need the IPv6 :-( */
  {
    wget_sockaddr remote;
    int len = sizeof (remote);
    struct sockaddr_in *ipv4_sock = ( struct sockaddr_in *)&remote;
    getpeername (RBUF_FD (rbuf), (struct sockaddr*)&remote, &len);
    switch(remote.sa.sa_family)
      {
        case AF_INET6:
          memcpy (addr, &remote.sin6.sin6_addr, 16);
	  break;
	case AF_INET:  
          map_ipv4_to_ip ((ip4_address *)&ipv4_sock->sin_addr, addr);
	  break;
	default:
	  abort();
	  return FTPINVPASV;
	  /* realy bad */
      }
  }
  return FTPOK;
}
#endif


/* Similar to ftp_port, but uses `PASV' to initiate the passive FTP
   transfer.  Reads the response from server and parses it.  Reads the
   host and port addresses and returns them.  */
uerr_t
ftp_pasv (struct rbuf *rbuf, ip_address *addr, unsigned short *port)
{
  char *request, *respline, *s;
  int nwritten, i;
  uerr_t err;
  unsigned char addr4[4];

#ifdef INET6
  if (ip_default_family == AF_INET6) 
    {
      err = ftp_epsv (rbuf, addr, port, "2");	/* try IPv6 with EPSV */
      if (FTPOK == err) 
        return FTPOK;
      err = ftp_epsv (rbuf, addr, port, "1");	/* try IPv4 with EPSV */
      if (FTPOK == err) 
        return FTPOK;
    }
#endif  
  /* Form the request.  */
  request = ftp_request ("PASV", NULL);
  /* And send it.  */
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get the server response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline != '2')
    {
      xfree (respline);
      return FTPNOPASV;
    }
  /* Parse the request.  */
  /* respline::=227 Entering Passive Mode (h1,h2,h3,h4,p1,p2). 	*/
  s = respline;
  for (s += 4; *s && !ISDIGIT (*s); s++);
  if (!*s)
    return FTPINVPASV;
  for (i = 0; i < 4; i++)
    {
      addr4[i] = 0;
      for (; ISDIGIT (*s); s++)
        addr4[i] = (*s - '0') + 10 * addr4[i];
      if (*s == ',')
        s++;
      else
        {
          xfree (respline);
          return FTPINVPASV;
        }
    }

  /* Eventually make an IPv4 in IPv6 adress if needed */
  map_ipv4_to_ip ((ip4_address *)addr4, addr);

  *port=0;
  for (; ISDIGIT (*s); s++)
    *port = (*s - '0') + 10 * (*port);
  if (*s == ',') 
    s++;
  else
    {
      xfree (respline);
      return FTPINVPASV;
    }

  {
    unsigned short port2 = 0; 
    for (; ISDIGIT (*s); s++) 
      port2 = (*s - '0') + 10 * port2;
    *port = (*port) * 256 + port2;
  }
  xfree (respline);
  return FTPOK;
}

/* Sends the TYPE request to the server.  */
uerr_t
ftp_type (struct rbuf *rbuf, int type)
{
  char *request, *respline;
  int nwritten;
  uerr_t err;
  char stype[2];

  /* Construct argument.  */
  stype[0] = type;
  stype[1] = 0;
  /* Send TYPE request.  */
  request = ftp_request ("TYPE", stype);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline != '2')
    {
      xfree (respline);
      return FTPUNKNOWNTYPE;
    }
  xfree (respline);
  /* All OK.  */
  return FTPOK;
}

/* Changes the working directory by issuing a CWD command to the
   server.  */
uerr_t
ftp_cwd (struct rbuf *rbuf, const char *dir)
{
  char *request, *respline;
  int nwritten;
  uerr_t err;

  /* Send CWD request.  */
  request = ftp_request ("CWD", dir);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline == '5')
    {
      xfree (respline);
      return FTPNSFOD;
    }
  if (*respline != '2')
    {
      xfree (respline);
      return FTPRERR;
    }
  xfree (respline);
  /* All OK.  */
  return FTPOK;
}

/* Sends REST command to the FTP server.  */
uerr_t
ftp_rest (struct rbuf *rbuf, long offset)
{
  char *request, *respline;
  int nwritten;
  uerr_t err;
  static char numbuf[24]; /* Buffer for the number */

  number_to_string (numbuf, offset);
  request = ftp_request ("REST", numbuf);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline != '3')
    {
      xfree (respline);
      return FTPRESTFAIL;
    }
  xfree (respline);
  /* All OK.  */
  return FTPOK;
}

/* Sends RETR command to the FTP server.  */
uerr_t
ftp_retr (struct rbuf *rbuf, const char *file)
{
  char *request, *respline;
  int nwritten;
  uerr_t err;

  /* Send RETR request.  */
  request = ftp_request ("RETR", file);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline == '5')
    {
      xfree (respline);
      return FTPNSFOD;
    }
  if (*respline != '1')
    {
      xfree (respline);
      return FTPRERR;
    }
  xfree (respline);
  /* All OK.  */
  return FTPOK;
}

/* Sends the LIST command to the server.  If FILE is NULL, send just
   `LIST' (no space).  */
uerr_t
ftp_list (struct rbuf *rbuf, const char *file)
{
  char *request, *respline;
  int nwritten;
  uerr_t err;

  /* Send LIST request.  */
  request = ftp_request ("LIST", file);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate respone.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline == '5')
    {
      xfree (respline);
      return FTPNSFOD;
    }
  if (*respline != '1')
    {
      xfree (respline);
      return FTPRERR;
    }
  xfree (respline);
  /* All OK.  */
  return FTPOK;
}

/* Sends the SYST command to the server. */
uerr_t
ftp_syst (struct rbuf *rbuf, enum stype *server_type)
{
  char *request, *respline;
  int nwritten;
  uerr_t err;

  /* Send SYST request.  */
  request = ftp_request ("SYST", NULL);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);

  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline == '5')
    {
      xfree (respline);
      return FTPSRVERR;
    }

  /* Skip the number (215, but 200 (!!!) in case of VMS) */
  strtok (respline, " ");
  
  /* Which system type has been reported (we are interested just in the
     first word of the server response)?  */
  request = strtok (NULL, " ");

  if (!strcasecmp (request, "VMS"))
    *server_type = ST_VMS;
  else if (!strcasecmp (request, "UNIX"))
    *server_type = ST_UNIX;
  else if (!strcasecmp (request, "WINDOWS_NT"))
    *server_type = ST_WINNT;
  else if (!strcasecmp (request, "MACOS"))
    *server_type = ST_MACOS;
  else
    *server_type = ST_OTHER;

  xfree (respline);
  /* All OK.  */
  return FTPOK;
}

/* Sends the PWD command to the server. */
uerr_t
ftp_pwd (struct rbuf *rbuf, char **pwd)
{
  char *request, *respline;
  int nwritten;
  uerr_t err;

  /* Send PWD request.  */
  request = ftp_request ("PWD", NULL);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      return err;
    }
  if (*respline == '5')
    {
      xfree (respline);
      return FTPSRVERR;
    }

  /* Skip the number (257), leading citation mark, trailing citation mark
     and everything following it. */
  strtok (respline, "\"");
  request = strtok (NULL, "\"");
  
  /* Has the `pwd' been already allocated?  Free! */
  FREE_MAYBE (*pwd);

  *pwd = xstrdup (request);

  xfree (respline);
  /* All OK.  */
  return FTPOK;
}

/* Sends the SIZE command to the server, and returns the value in 'size'.
 * If an error occurs, size is set to zero. */
uerr_t
ftp_size (struct rbuf *rbuf, const char *file, long int *size)
{
  char *request, *respline;
  int nwritten;
  uerr_t err;

  /* Send PWD request.  */
  request = ftp_request ("SIZE", file);
  nwritten = iwrite (RBUF_FD (rbuf), request, strlen (request));
  if (nwritten < 0)
    {
      xfree (request);
      *size = 0;
      return WRITEFAILED;
    }
  xfree (request);
  /* Get appropriate response.  */
  err = ftp_response (rbuf, &respline);
  if (err != FTPOK)
    {
      xfree (respline);
      *size = 0;
      return err;
    }
  if (*respline == '5')
    {
      /* 
       * Probably means SIZE isn't supported on this server.
       * Error is nonfatal since SIZE isn't in RFC 959 
       */
      xfree (respline);
      *size = 0;
      return FTPOK;
    }

  errno = 0;
  *size = strtol (respline + 4, NULL, 0);
  if (errno) 
    {
      /* 
       * Couldn't parse the response for some reason.  On the (few)
       * tests I've done, the response is 213 <SIZE> with nothing else -
       * maybe something a bit more resilient is necessary.  It's not a
       * fatal error, however.
       */
      xfree (respline);
      *size = 0;
      return FTPOK;
    }

  xfree (respline);
  /* All OK.  */
  return FTPOK;
}

/* If URL's params are of the form "type=X", return character X.
   Otherwise, return 'I' (the default type).  */
char
ftp_process_type (const char *params)
{
  if (params
      && 0 == strncasecmp (params, "type=", 5)
      && params[5] != '\0')
    return TOUPPER (params[5]);
  else
    return 'I';
}