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

#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;
}

/* 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, *bytes;
  unsigned char *in_addr;
  int nwritten;
  unsigned short port;

  /* Setting port to 0 lets the system choose a free port.  */
  port = 0;
  /* Bind the port.  */
  err = bindport (&port);
  if (err != BINDOK)
    return err;
  /* Get the address of this side of the connection.  */
  if (!(in_addr = conaddr (RBUF_FD (rbuf))))
    return HOSTERR;
  /* Construct the argument of PORT (of the form a,b,c,d,e,f).  */
  bytes = (char *)alloca (6 * 4 + 1);
  sprintf (bytes, "%d,%d,%d,%d,%d,%d", in_addr[0], in_addr[1],
          in_addr[2], in_addr[3], (unsigned) (port & 0xff00) >> 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;
}

/* 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, unsigned char *addr)
{
  char *request, *respline, *s;
  int nwritten, i;
  uerr_t err;

  /* 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.  */
  s = respline;
  for (s += 4; *s && !ISDIGIT (*s); s++);
  if (!*s)
    return FTPINVPASV;
  for (i = 0; i < 6; i++)
    {
      addr[i] = 0;
      for (; ISDIGIT (*s); s++)
        addr[i] = (*s - '0') + 10 * addr[i];
      if (*s == ',')
        s++;
      else if (i < 5)
        {
          /* When on the last number, anything can be a terminator.  */
          xfree (respline);
          return FTPINVPASV;
        }
    }
  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[20]; /* Buffer for the number */

  long_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;
}