apt/methods/ftp.cc

// -*- mode: cpp; mode: fold -*-
// Description								/*{{{*/
// $Id: ftp.cc,v 1.1 1999/03/15 06:00:59 jgg Exp $
/* ######################################################################

   HTTP Aquire Method - This is the FTP aquire method for APT.

   This is a very simple implementation that does not try to optimize
   at all. Commands are sent syncronously with the FTP server (as the
   rfc recommends, but it is not really necessary..) and no tricks are
   done to speed things along.
							       
   ##################################################################### */
									/*}}}*/
// Include Files							/*{{{*/
#include <apt-pkg/fileutl.h>
#include <apt-pkg/acquire-method.h>
#include <apt-pkg/error.h>
#include <apt-pkg/md5.h>
#include "ftp.h"

#include <sys/stat.h>
#include <sys/time.h>
#include <utime.h>
#include <unistd.h>
#include <signal.h>
#include <stdio.h>
#include <errno.h>
#include <stdarg.h>

// Internet stuff
#include <netinet/in.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>

									/*}}}*/

unsigned long TimeOut = 120;
URI Proxy;
bool Debug;

// FTPConn::FTPConn - Constructor					/*{{{*/
// ---------------------------------------------------------------------
/* */
FTPConn::FTPConn(URI Srv) : Len(0), ServerFd(-1), DataFd(-1), 
                            DataListenFd(-1), ServerName(Srv)
{
   Debug = true;
   memset(&PasvAddr,0,sizeof(PasvAddr));
}
									/*}}}*/
// FTPConn::~FTPConn - Destructor					/*{{{*/
// ---------------------------------------------------------------------
/* */
FTPConn::~FTPConn()
{
   Close();
}
									/*}}}*/
// FTPConn::Close - Close down the connection				/*{{{*/
// ---------------------------------------------------------------------
/* Just tear down the socket and data socket */
void FTPConn::Close()
{
   close(ServerFd);
   ServerFd = -1;
   close(DataFd);
   DataFd = -1;
   close(DataListenFd);
   DataListenFd = -1;
   memset(&PasvAddr,0,sizeof(PasvAddr));
}
									/*}}}*/
// FTPConn::Open - Open a new connection				/*{{{*/
// ---------------------------------------------------------------------
/* Connect to the server using a non-blocking connection and perform a 
   login. */
string LastHost;
in_addr LastHostA;
bool FTPConn::Open()
{
   // Use the already open connection if possible.
   if (ServerFd != -1)
      return true;
   
   Close();

   // Determine the proxy setting
   if (getenv("ftp_proxy") == 0)
   {
      string DefProxy = _config->Find("Acquire::ftp::Proxy");
      string SpecificProxy = _config->Find("Acquire::ftp::Proxy::" + ServerName.Host);
      if (SpecificProxy.empty() == false)
      {
	 if (SpecificProxy == "DIRECT")
	    Proxy = "";
	 else
	    Proxy = SpecificProxy;
      }   
      else
	 Proxy = DefProxy;
   }
   else
      Proxy = getenv("ftp_proxy");
   
   // Determine what host and port to use based on the proxy settings
   int Port = 21;
   string Host;   
   if (Proxy.empty() == true)
   {
      if (ServerName.Port != 0)
	 Port = ServerName.Port;
      else
	 ServerName.Port = Port;
      Host = ServerName.Host;
   }
   else
   {
      if (Proxy.Port != 0)
	 Port = Proxy.Port;
      Host = Proxy.Host;
   }
   
   /* We used a cached address record.. Yes this is against the spec but
      the way we have setup our rotating dns suggests that this is more
      sensible */
   if (LastHost != Host)
   {
//      Owner->Status("Connecting to %s",Host.c_str());

      // Lookup the host
      hostent *Addr = gethostbyname(Host.c_str());
      if (Addr == 0 || Addr->h_addr_list[0] == 0)
	 return _error->Error("Could not resolve '%s'",Host.c_str());
      LastHost = Host;
      LastHostA = *(in_addr *)(Addr->h_addr_list[0]);
   }
   
//   Owner->Status("Connecting to %s (%s)",Host.c_str(),inet_ntoa(LastHostA));
   
   // Get a socket
   if ((ServerFd = socket(AF_INET,SOCK_STREAM,0)) < 0)
      return _error->Errno("socket","Could not create a socket");
   
   // Connect to the server
   struct sockaddr_in server;
   server.sin_family = AF_INET;
   server.sin_port = htons(Port);
   server.sin_addr = LastHostA;
   SetNonBlock(ServerFd,true);
   if (connect(ServerFd,(sockaddr *)&server,sizeof(server)) < 0 &&
       errno != EINPROGRESS)
      return _error->Errno("socket","Could not create a socket");
   Peer = server;
   
   /* This implements a timeout for connect by opening the connection
      nonblocking */
   if (WaitFd(ServerFd,true,TimeOut) == false)
      return _error->Error("Could not connect, connection timed out");
   unsigned int Err;
   unsigned int Len = sizeof(Err);
   if (getsockopt(ServerFd,SOL_SOCKET,SO_ERROR,&Err,&Len) != 0)
      return _error->Errno("getsockopt","Failed");
   if (Err != 0)
      return _error->Error("Could not connect.");

   return Login();
}
									/*}}}*/
// FTPConn::Login - Login to the remote server				/*{{{*/
// ---------------------------------------------------------------------
/* This performs both normal login and proxy login using a simples script
   stored in the config file. */
bool FTPConn::Login()
{
   unsigned int Tag;
   string Msg;
   
   // Setup the variables needed for authentication
   string User = "anonymous";
   string Pass = "apt_get_ftp_2.0@debian.linux.user";

   // Fill in the user/pass
   if (ServerName.User.empty() == false)
      User = ServerName.User;
   if (ServerName.Password.empty() == false)
      Pass = ServerName.Password;
       
   // Perform simple login
   if (Proxy.empty() == true)
   {
      // Read the initial response
      if (ReadResp(Tag,Msg) == false)
	 return false;
      if (Tag >= 400)
	 return _error->Error("Server refused our connection and said: %s",Msg.c_str());
      
      // Send the user
      if (WriteMsg(Tag,Msg,"USER %s",User.c_str()) == false)
	 return false;
      if (Tag >= 400)
	 return _error->Error("USER failed, server said: %s",Msg.c_str());
      
      // Send the Password
      if (WriteMsg(Tag,Msg,"PASS %s",Pass.c_str()) == false)
	 return false;
      if (Tag >= 400)
	 return _error->Error("PASS failed, server said: %s",Msg.c_str());
      
      // Enter passive mode
      TryPassive = false;
      if (_config->Exists("Acquire::FTP::Passive::" + ServerName.Host) == true &&
	  _config->FindB("Acquire::FTP::Passive::" + ServerName.Host,true) == true)
      {
	 TryPassive = true;
      }      
      else
      {
	 if (_config->FindB("Acquire::FTP::Passive",true) == true)
	    TryPassive = true;
      }      
   }
   else
   {      
      // Read the initial response
      if (ReadResp(Tag,Msg) == false)
	 return false;
      if (Tag >= 400)
	 return _error->Error("Server refused our connection and said: %s",Msg.c_str());
      
      // Perform proxy script execution
      Configuration::Item const *Opts = _config->Tree("Acquire::ftp::ProxyLogin");
      if (Opts == 0 || Opts->Child == 0)
	 return _error->Error("A proxy server was specified but no login "
			      "script, Acquire::ftp::ProxyLogin is empty.");
      Opts = Opts->Child;

      // Iterate over the entire login script
      for (; Opts != 0; Opts = Opts->Next)
      {
	 if (Opts->Value.empty() == true)
	    continue;
	 
	 // Substitute the variables into the command
	 char SitePort[20];
	 sprintf(SitePort,"%u",ServerName.Port);
	 string Tmp = Opts->Value;
	 Tmp = SubstVar(Tmp,"$(PROXY_USER)",Proxy.User);
	 Tmp = SubstVar(Tmp,"$(PROXY_PASS)",Proxy.Password);
	 Tmp = SubstVar(Tmp,"$(SITE_USER)",User);
	 Tmp = SubstVar(Tmp,"$(SITE_PASS)",Pass);
	 Tmp = SubstVar(Tmp,"$(SITE_PORT)",SitePort);
	 Tmp = SubstVar(Tmp,"$(SITE)",ServerName.Host);

	 // Send the command
	 if (WriteMsg(Tag,Msg,"%s",Tmp.c_str()) == false)
	    return false;
	 if (Tag >= 400)
	    return _error->Error("Login script command '%s' failed, server said: %s",Tmp.c_str(),Msg.c_str());	 
      }
      
      // Enter passive mode
      TryPassive = false;
      if (_config->Exists("Acquire::FTP::Passive::" + ServerName.Host) == true &&
	  _config->FindB("Acquire::FTP::Passive::" + ServerName.Host,true) == true)
      {
	 TryPassive = true;
      }      
      else
      {
	 if (_config->Exists("Acquire::FTP::Proxy::Passive") == true &&
	     _config->FindB("Acquire::FTP::Proxy::Passive",true) == true)
	    TryPassive = true;
	 else
	    if (_config->FindB("Acquire::FTP::Passive",true) == true)
	       TryPassive = true;	       
      }            
   }

   // Binary mode
   if (WriteMsg(Tag,Msg,"TYPE I") == false)
      return false;
   if (Tag >= 400)
      return _error->Error("TYPE failed, server said: %s",Msg.c_str());
   
   return true;
}
									/*}}}*/
// FTPConn::ReadLine - Read a line from the server			/*{{{*/
// ---------------------------------------------------------------------
/* This performs a very simple buffered read. */
bool FTPConn::ReadLine(string &Text)
{
   // Suck in a line
   while (Len < sizeof(Buffer))
   {
      // Scan the buffer for a new line
      for (unsigned int I = 0; I != Len; I++)
      {
	 // Escape some special chars
	 if (Buffer[I] == 0)
	    Buffer[I] = '?';
	 
	 // End of line?
	 if (Buffer[I] != '\n')
	    continue;
	 
	 I++;
	 Text = string(Buffer,I);
	 memmove(Buffer,Buffer+I,Len - I);
	 Len -= I;	 
	 return true;
      }

      // Wait for some data..
      if (WaitFd(ServerFd,false,TimeOut) == false)
	 return _error->Error("Connection timeout");
      
      // Suck it back
      int Res = read(ServerFd,Buffer,sizeof(Buffer) - Len);
      if (Res <= 0)
	 return _error->Errno("read","Read error");
      Len += Res;
   }

   return _error->Error("A response overflowed the buffer.");
}
									/*}}}*/
// FTPConn::ReadResp - Read a full response from the server		/*{{{*/
// ---------------------------------------------------------------------
/* This reads a reply code from the server, it handles both p */
bool FTPConn::ReadResp(unsigned int &Ret,string &Text)
{
   // Grab the first line of the response
   string Msg;
   if (ReadLine(Msg) == false)
       return false;
   
   // Get the ID code
   char *End;   
   Ret = strtol(Msg.c_str(),&End,10);
   if (End - Msg.c_str() != 3)
      return _error->Error("Protocol corruption");

   // All done ?
   Text = Msg.c_str()+4;
   if (*End == ' ')
   {
      if (Debug == true)
	 cout << "<- '" << QuoteString(Text,"") << "'" << endl;
      return true;
   }
   
   if (*End != '-')
      return _error->Error("Protocol corruption");
   
   /* Okay, here we do the continued message trick. This is foolish, but
      proftpd follows the protocol as specified and wu-ftpd doesn't, so 
      we filter. I wonder how many clients break if you use proftpd and
      put a '- in the 3rd spot in the message? */
   char Leader[4];
   strncpy(Leader,Msg.c_str(),3);
   Leader[3] = 0;
   while (ReadLine(Msg) == true)
   {
      // Short, it must be using RFC continuation..
      if (Msg.length() < 4)
      {
	 Text += Msg;
	 continue;
      }
      
      // Oops, finished
      if (strncmp(Msg.c_str(),Leader,3) == 0 && Msg[3] == ' ')
      {
	 Text += Msg.c_str()+4;
	 break;
      }
      
      // This message has the wu-ftpd style reply code prefixed
      if (strncmp(Msg.c_str(),Leader,3) == 0 && Msg[3] == '-')
      {
	 Text += Msg.c_str()+4;
	 continue;
      }
      
      // Must be RFC style prefixing
      Text += Msg;
   }	   

   if (Debug == true && _error->PendingError() == false)
      cout << "<- '" << QuoteString(Text,"") << "'" << endl;
      
   return !_error->PendingError();
}
									/*}}}*/
// FTPConn::WriteMsg - Send a message to the server			/*{{{*/
// ---------------------------------------------------------------------
/* Simple printf like function.. */
bool FTPConn::WriteMsg(unsigned int &Ret,string &Text,const char *Fmt,...)
{
   va_list args;
   va_start(args,Fmt);

   // sprintf the description
   char S[400];
   vsnprintf(S,sizeof(S) - 4,Fmt,args);
   strcat(S,"\r\n");
 
   if (Debug == true)
      cout << "-> '" << QuoteString(S,"") << "'" << endl;

   // Send it off
   unsigned long Len = strlen(S);
   unsigned long Start = 0;
   while (Len != 0)
   {
      if (WaitFd(ServerFd,true,TimeOut) == false)
	 return _error->Error("Connection timeout");
      
      int Res = write(ServerFd,S + Start,Len);
      if (Res <= 0)
	 return _error->Errno("write","Write Error");
      Len -= Res;
      Start += Res;
   }
   
   return ReadResp(Ret,Text);
}
									/*}}}*/
// FTPConn::GoPasv - Enter Passive mode					/*{{{*/
// ---------------------------------------------------------------------
/* Try to enter passive mode, the return code does not indicate if passive
   mode could or could not be established, only if there was a fatal error. 
   Borrowed mostly from lftp. We have to enter passive mode every time 
 we make a data connection :| */
bool FTPConn::GoPasv()
{
   // Try to enable pasv mode
   unsigned int Tag;
   string Msg;
   if (WriteMsg(Tag,Msg,"PASV") == false)
      return false;
   
   // Unsupported function
   string::size_type Pos = Msg.find('(');
   if (Tag >= 400 || Pos == string::npos)
   {
      memset(&PasvAddr,0,sizeof(PasvAddr));
      return true;
   }

   // Scan it
   unsigned a0,a1,a2,a3,p0,p1;
   if (sscanf(Msg.c_str() + Pos,"(%u,%u,%u,%u,%u,%u)",&a0,&a1,&a2,&a3,&p0,&p1) != 6)
   {
      memset(&PasvAddr,0,sizeof(PasvAddr));
      return true;
   }
   
   // lftp used this horrid byte order manipulation.. Ik.
   PasvAddr.sin_family = AF_INET;
   unsigned char *a;
   unsigned char *p;
   a = (unsigned char *)&PasvAddr.sin_addr;
   p = (unsigned char *)&PasvAddr.sin_port;
   
   // Some evil servers return 0 to mean their addr
   if (a0 == 0 && a1 == 0 && a2 == 0 && a3 == 0)
   {
      PasvAddr.sin_addr = Peer.sin_addr;
   }
   else
   {
      a[0] = a0; 
      a[1] = a1; 
      a[2] = a2; 
      a[3] = a3;
   }
   
   p[0] = p0;
   p[1] = p1;
   
   return true;
}
									/*}}}*/
// FTPConn::Size - Return the size of a file				/*{{{*/
// ---------------------------------------------------------------------
/* Grab the file size from the server, 0 means no size or empty file */
unsigned long FTPConn::Size(const char *Path)
{
   // Query the size
   unsigned int Tag;
   string Msg;
   if (WriteMsg(Tag,Msg,"SIZE %s",Path) == false)
      return false;
   
   char *End;
   unsigned long Size = strtol(Msg.c_str(),&End,10);
   if (Tag >= 400 || End == Msg.c_str())
      return 0;
   return Size;
}
									/*}}}*/
// FTPConn::ModTime - Return the modification time of the file		/*{{{*/
// ---------------------------------------------------------------------
/* Like Size no error is returned if the command is not supported. If the
   command fails then time is set to the current time of day to fool 
   date checks. */
bool FTPConn::ModTime(const char *Path, time_t &Time)
{
   Time = time(&Time);
   
   // Query the mod time
   unsigned int Tag;
   string Msg;
   if (WriteMsg(Tag,Msg,"MDTM %s",Path) == false)
      return false;
   if (Tag >= 400 || Msg.empty() == true || isdigit(Msg[0]) == 0)
      return true;
   
   // Parse it
   struct tm tm;
   memset(&tm,0,sizeof(tm));   
   if (sscanf(Msg.c_str(),"%4d%2d%2d%2d%2d%2d",&tm.tm_year,&tm.tm_mon,
	      &tm.tm_mday,&tm.tm_hour,&tm.tm_min,&tm.tm_sec) != 6)
      return true;
   
   tm.tm_year -= 1900;
   tm.tm_mon--;
   
   /* We use timegm from the GNU C library, libapt-pkg will provide this
      symbol if it does not exist */
   Time = timegm(&tm);
   return true;
}
									/*}}}*/
// FTPConn::CreateDataFd - Get a data connection			/*{{{*/
// ---------------------------------------------------------------------
/* Create the data connection. Call FinalizeDataFd after this though.. */
bool FTPConn::CreateDataFd()
{
   close(DataFd);
   DataFd = -1;
   
   // Attempt to enter passive mode.
   if (TryPassive == true)
   {
      if (GoPasv() == false)
	 return false;
      
      // Oops, didn't work out, don't bother trying again.
      if (PasvAddr.sin_port == 0)
	 TryPassive = false;
   }
   
   // Passive mode?
   if (PasvAddr.sin_port != 0)
   {
      // Get a socket
      if ((DataFd = socket(AF_INET,SOCK_STREAM,0)) < 0)
	 return _error->Errno("socket","Could not create a socket");
      
      // Connect to the server
      SetNonBlock(DataFd,true);
      if (connect(DataFd,(sockaddr *)&PasvAddr,sizeof(PasvAddr)) < 0 &&
	  errno != EINPROGRESS)
	 return _error->Errno("socket","Could not create a socket");
   
      /* This implements a timeout for connect by opening the connection
       nonblocking */
      if (WaitFd(ServerFd,true,TimeOut) == false)
	 return _error->Error("Could not connect data socket, connection timed out");
      unsigned int Err;
      unsigned int Len = sizeof(Err);
      if (getsockopt(ServerFd,SOL_SOCKET,SO_ERROR,&Err,&Len) != 0)
	 return _error->Errno("getsockopt","Failed");
      if (Err != 0)
	 return _error->Error("Could not connect.");
      
      return true;
   }
   
   // Port mode :<
   if (DataListenFd == -1)
   {
      // Get a socket
      if ((DataListenFd = socket(AF_INET,SOCK_STREAM,0)) < 0)
	 return _error->Errno("socket","Could not create a socket");
      
      // Bind and listen
      sockaddr_in Addr;
      memset(&Addr,0,sizeof(Addr));
      if (bind(DataListenFd,(sockaddr *)&Addr,sizeof(Addr)) < 0)
	 return _error->Errno("bind","Could not bind a socket");
      if (listen(DataListenFd,1) < 0)
	 return _error->Errno("listen","Could not listen on the socket");
      SetNonBlock(DataListenFd,true);
   }
   
   // Determine the name to send to the remote
   sockaddr_in Addr;
   sockaddr_in Addr2;
   socklen_t Jnk = sizeof(Addr);
   if (getsockname(DataListenFd,(sockaddr *)&Addr,&Jnk) < 0)
      return _error->Errno("getsockname","Could not determine the socket's name");
   Jnk = sizeof(Addr2);
   if (getsockname(ServerFd,(sockaddr *)&Addr2,&Jnk) < 0)
      return _error->Errno("getsockname","Could not determine the socket's name");
   
   // This bit ripped from qftp
   unsigned long badr = ntohl(*(unsigned long *)&Addr2.sin_addr);
   unsigned long bp = ntohs(Addr.sin_port);

   // Send the port command
   unsigned int Tag;
   string Msg;
   if (WriteMsg(Tag,Msg,"PORT %d,%d,%d,%d,%d,%d", 
		(int) (badr >> 24) & 0xff, (int) (badr >> 16) & 0xff, 
		(int) (badr >> 8) & 0xff,  (int) badr & 0xff, 
		(int) (bp >> 8) & 0xff, (int) bp & 0xff) == false)
      return false;
   if (Tag >= 400)
      return _error->Error("Unable to send port command");

   return true;
}
									/*}}}*/
// FTPConn::Finalize - Complete the Data connection			/*{{{*/
// ---------------------------------------------------------------------
/* If the connection is in port mode this waits for the other end to hook
   up to us. */
bool FTPConn::Finalize()
{
   // Passive mode? Do nothing
   if (PasvAddr.sin_port != 0)
      return true;
   
   // Close any old socket..
   close(DataFd);
   DataFd = -1;
   
   // Wait for someone to connect..
   if (WaitFd(DataListenFd,false,TimeOut) == false)
      return _error->Error("Data socket connect timed out");
      
   // Accept the connection
   struct sockaddr_in Addr;
   socklen_t Len = sizeof(Addr);
   DataFd = accept(DataListenFd,(struct sockaddr *)&Addr,&Len);
   if (DataFd < 0)
      return _error->Errno("accept","Unable to accept connection");

   return true;
}
									/*}}}*/
// FTPConn::Get - Get a file						/*{{{*/
// ---------------------------------------------------------------------
/* This opens a data connection, sends REST and RETR and then
   transfers the file over. */
bool FTPConn::Get(const char *Path,FileFd &To,unsigned long Resume)
{
   if (CreateDataFd() == false)
      return false;

   unsigned int Tag;
   string Msg;
   if (Resume != 0)
   {      
      if (WriteMsg(Tag,Msg,"REST %u",Resume) == false)
	 return false;
      if (Tag >= 400)
	 Resume = 0;
   }
   
   if (To.Truncate(Resume) == false)
      return false;
   
   // Send the get command
   if (WriteMsg(Tag,Msg,"RETR %s",Path) == false)
      return false;
   
   if (Tag >= 400)
      return _error->Error("Unable to fetch file, server said '%s'",Msg.c_str());
   
   // Finish off the data connection
   if (Finalize() == false)
      return false;
   
   // Copy loop
   unsigned char Buffer[4096];
   while (1)
   {
      // Wait for some data..
      if (WaitFd(DataFd,false,TimeOut) == false)
	 return _error->Error("Data socket connect timed out");
    
      // Read the data..
      int Res = read(DataFd,Buffer,sizeof(Buffer));
      if (Res == 0)
	 break;
      if (Res < 0)
      {
	 if (errno == EAGAIN)
	    continue;
	 break;
      }
      
      if (To.Write(Buffer,Res) == false)
	 return false;
   }

   // All done
   close(DataFd);
   DataFd = -1;
   
   // Read the closing message from the server
   if (ReadResp(Tag,Msg) == false)
      return false;
   if (Tag >= 400)
      return _error->Error("Data transfer failed, server said '%s'",Msg.c_str());
   return true;
}
									/*}}}*/

int main()
{
   FTPConn Con(URI("ftp://va.debian.org/debian/README"));
   string Msg;
   _config->Set("Acquire::FTP::Passive","false");
   
   while (1)
   {
      if (Con.Open() == false)
	 break;
      cout << "Size: " << Con.Size("/debian/README") << endl;
      
      time_t Time;
      Con.ModTime("/debian/README",Time);      
      cout << "Time: " << TimeRFC1123(Time) << endl;
   
      {
	 
      FileFd F("t",FileFd::WriteEmpty);
      Con.Get("/debian/README",F);
      }
      
      {
	 
      FileFd F("t3",FileFd::WriteEmpty);
      Con.Get("/debian/README.pgp",F);
      }
      
      break;
   }
   
   _error->DumpErrors();
   return 0;
}