refactor http client implementation

No effective behavior change, just shuffling big junks of code between
methods and classes to split them into those strongly related to our
client implementation and those implementing HTTP.

The idea is to get HTTPS to a point in which most of the implementation
can be shared even though the client implementations itself is
completely different. This isn't anywhere near yet though, but it should
beenough to reuse at least a few lines from http in https now.

Git-Dch: Ignore

1 files changed, 665 insertions, 0 deletions

diff --git a/methods/server.cc b/methods/server.cc
new file mode 100644
index 000000000..a2128441c
--- /dev/null
+++ b/methods/server.cc
@@ -0,0 +1,665 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   HTTP and HTTPS share a lot of common code and these classes are
+   exactly the dumping ground for this common code
+
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/acquire-method.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/netrc.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 <string.h>
+#include <climits>
+#include <iostream>
+#include <map>
+
+// Internet stuff
+#include <netdb.h>
+
+#include "config.h"
+#include "connect.h"
+#include "rfc2553emu.h"
+#include "http.h"
+
+#include <apti18n.h>
+									/*}}}*/
+using namespace std;
+
+string ServerMethod::FailFile;
+int ServerMethod::FailFd = -1;
+time_t ServerMethod::FailTime = 0;
+
+// ServerState::RunHeaders - Get the headers before the data		/*{{{*/
+// ---------------------------------------------------------------------
+/* Returns 0 if things are OK, 1 if an IO error occurred and 2 if a header
+   parse error occurred */
+ServerState::RunHeadersResult ServerState::RunHeaders(FileFd * const File)
+{
+   State = Header;
+   
+   Owner->Status(_("Waiting for headers"));
+
+   Major = 0; 
+   Minor = 0; 
+   Result = 0; 
+   Size = 0; 
+   StartPos = 0;
+   Encoding = Closes;
+   HaveContent = false;
+   time(&Date);
+
+   do
+   {
+      string Data;
+      if (ReadHeaderLines(Data) == false)
+	 continue;
+
+      if (Owner->Debug == true)
+	 clog << Data;
+      
+      for (string::const_iterator I = Data.begin(); I < Data.end(); ++I)
+      {
+	 string::const_iterator J = I;
+	 for (; J != Data.end() && *J != '\n' && *J != '\r'; ++J);
+	 if (HeaderLine(string(I,J)) == false)
+	    return RUN_HEADERS_PARSE_ERROR;
+	 I = J;
+      }
+
+      // 100 Continue is a Nop...
+      if (Result == 100)
+	 continue;
+      
+      // Tidy up the connection persistance state.
+      if (Encoding == Closes && HaveContent == true)
+	 Persistent = false;
+      
+      return RUN_HEADERS_OK;
+   }
+   while (LoadNextResponse(false, File) == true);
+   
+   return RUN_HEADERS_IO_ERROR;
+}
+									/*}}}*/
+// ServerState::HeaderLine - Process a header line			/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool ServerState::HeaderLine(string Line)
+{
+   if (Line.empty() == true)
+      return true;
+
+   string::size_type Pos = Line.find(' ');
+   if (Pos == string::npos || Pos+1 > Line.length())
+   {
+      // Blah, some servers use "connection:closes", evil.
+      Pos = Line.find(':');
+      if (Pos == string::npos || Pos + 2 > Line.length())
+	 return _error->Error(_("Bad header line"));
+      Pos++;
+   }
+
+   // Parse off any trailing spaces between the : and the next word.
+   string::size_type Pos2 = Pos;
+   while (Pos2 < Line.length() && isspace(Line[Pos2]) != 0)
+      Pos2++;
+      
+   string Tag = string(Line,0,Pos);
+   string Val = string(Line,Pos2);
+   
+   if (stringcasecmp(Tag.c_str(),Tag.c_str()+4,"HTTP") == 0)
+   {
+      // Evil servers return no version
+      if (Line[4] == '/')
+      {
+	 int const elements = sscanf(Line.c_str(),"HTTP/%3u.%3u %3u%359[^\n]",&Major,&Minor,&Result,Code);
+	 if (elements == 3)
+	 {
+	    Code[0] = '\0';
+	    if (Owner->Debug == true)
+	       clog << "HTTP server doesn't give Reason-Phrase for " << Result << std::endl;
+	 }
+	 else if (elements != 4)
+	    return _error->Error(_("The HTTP server sent an invalid reply header"));
+      }
+      else
+      {
+	 Major = 0;
+	 Minor = 9;
+	 if (sscanf(Line.c_str(),"HTTP %3u%359[^\n]",&Result,Code) != 2)
+	    return _error->Error(_("The HTTP server sent an invalid reply header"));
+      }
+
+      /* Check the HTTP response header to get the default persistance
+         state. */
+      if (Major < 1)
+	 Persistent = false;
+      else
+      {
+	 if (Major == 1 && Minor == 0)
+	    Persistent = false;
+	 else
+	    Persistent = true;
+      }
+
+      return true;
+   }      
+      
+   if (stringcasecmp(Tag,"Content-Length:") == 0)
+   {
+      if (Encoding == Closes)
+	 Encoding = Stream;
+      HaveContent = true;
+      
+      // The length is already set from the Content-Range header
+      if (StartPos != 0)
+	 return true;
+
+      Size = strtoull(Val.c_str(), NULL, 10);
+      if (Size >= std::numeric_limits<unsigned long long>::max())
+	 return _error->Errno("HeaderLine", _("The HTTP server sent an invalid Content-Length header"));
+      else if (Size == 0)
+	 HaveContent = false;
+      return true;
+   }
+
+   if (stringcasecmp(Tag,"Content-Type:") == 0)
+   {
+      HaveContent = true;
+      return true;
+   }
+   
+   if (stringcasecmp(Tag,"Content-Range:") == 0)
+   {
+      HaveContent = true;
+
+      // §14.16 says 'byte-range-resp-spec' should be a '*' in case of 416
+      if (Result == 416 && sscanf(Val.c_str(), "bytes */%llu",&Size) == 1)
+      {
+	 StartPos = 1; // ignore Content-Length, it would override Size
+	 HaveContent = false;
+      }
+      else if (sscanf(Val.c_str(),"bytes %llu-%*u/%llu",&StartPos,&Size) != 2)
+	 return _error->Error(_("The HTTP server sent an invalid Content-Range header"));
+      if ((unsigned long long)StartPos > Size)
+	 return _error->Error(_("This HTTP server has broken range support"));
+      return true;
+   }
+   
+   if (stringcasecmp(Tag,"Transfer-Encoding:") == 0)
+   {
+      HaveContent = true;
+      if (stringcasecmp(Val,"chunked") == 0)
+	 Encoding = Chunked;      
+      return true;
+   }
+
+   if (stringcasecmp(Tag,"Connection:") == 0)
+   {
+      if (stringcasecmp(Val,"close") == 0)
+	 Persistent = false;
+      if (stringcasecmp(Val,"keep-alive") == 0)
+	 Persistent = true;
+      return true;
+   }
+   
+   if (stringcasecmp(Tag,"Last-Modified:") == 0)
+   {
+      if (RFC1123StrToTime(Val.c_str(), Date) == false)
+	 return _error->Error(_("Unknown date format"));
+      return true;
+   }
+
+   if (stringcasecmp(Tag,"Location:") == 0)
+   {
+      Location = Val;
+      return true;
+   }
+
+   return true;
+}
+									/*}}}*/
+// ServerState::ServerState - Constructor				/*{{{*/
+ServerState::ServerState(URI Srv, ServerMethod *Owner) : ServerName(Srv), TimeOut(120), Owner(Owner)
+{
+   Reset();
+}
+									/*}}}*/
+
+bool ServerMethod::Configuration(string Message)			/*{{{*/
+{
+   return pkgAcqMethod::Configuration(Message);
+}
+									/*}}}*/
+
+// ServerMethod::DealWithHeaders - Handle the retrieved header data	/*{{{*/
+// ---------------------------------------------------------------------
+/* We look at the header data we got back from the server and decide what
+   to do. Returns DealWithHeadersResult (see http.h for details).
+ */
+ServerMethod::DealWithHeadersResult
+ServerMethod::DealWithHeaders(FetchResult &Res)
+{
+   // Not Modified
+   if (Server->Result == 304)
+   {
+      unlink(Queue->DestFile.c_str());
+      Res.IMSHit = true;
+      Res.LastModified = Queue->LastModified;
+      return IMS_HIT;
+   }
+   
+   /* Redirect
+    *
+    * Note that it is only OK for us to treat all redirection the same
+    * because we *always* use GET, not other HTTP methods.  There are
+    * three redirection codes for which it is not appropriate that we
+    * redirect.  Pass on those codes so the error handling kicks in.
+    */
+   if (AllowRedirect
+       && (Server->Result > 300 && Server->Result < 400)
+       && (Server->Result != 300       // Multiple Choices
+           && Server->Result != 304    // Not Modified
+           && Server->Result != 306))  // (Not part of HTTP/1.1, reserved)
+   {
+      if (Server->Location.empty() == true);
+      else if (Server->Location[0] == '/' && Queue->Uri.empty() == false)
+      {
+	 URI Uri = Queue->Uri;
+	 if (Uri.Host.empty() == false)
+            NextURI = URI::SiteOnly(Uri);
+	 else
+	    NextURI.clear();
+	 NextURI.append(DeQuoteString(Server->Location));
+	 return TRY_AGAIN_OR_REDIRECT;
+      }
+      else
+      {
+         NextURI = DeQuoteString(Server->Location);
+         URI tmpURI = NextURI;
+         // Do not allow a redirection to switch protocol
+         if (tmpURI.Access == "http")
+            return TRY_AGAIN_OR_REDIRECT;
+      }
+      /* else pass through for error message */
+   }
+   // retry after an invalid range response without partial data
+   else if (Server->Result == 416)
+   {
+      struct stat SBuf;
+      if (stat(Queue->DestFile.c_str(),&SBuf) >= 0 && SBuf.st_size > 0)
+      {
+	 if ((unsigned long long)SBuf.st_size == Server->Size)
+	 {
+	    // the file is completely downloaded, but was not moved
+	    Server->StartPos = Server->Size;
+	    Server->Result = 200;
+	    Server->HaveContent = false;
+	 }
+	 else if (unlink(Queue->DestFile.c_str()) == 0)
+	 {
+	    NextURI = Queue->Uri;
+	    return TRY_AGAIN_OR_REDIRECT;
+	 }
+      }
+   }
+
+   /* We have a reply we dont handle. This should indicate a perm server
+      failure */
+   if (Server->Result < 200 || Server->Result >= 300)
+   {
+      char err[255];
+      snprintf(err,sizeof(err)-1,"HttpError%i",Server->Result);
+      SetFailReason(err);
+      _error->Error("%u %s",Server->Result,Server->Code);
+      if (Server->HaveContent == true)
+	 return ERROR_WITH_CONTENT_PAGE;
+      return ERROR_UNRECOVERABLE;
+   }
+
+   // This is some sort of 2xx 'data follows' reply
+   Res.LastModified = Server->Date;
+   Res.Size = Server->Size;
+   
+   // Open the file
+   delete File;
+   File = new FileFd(Queue->DestFile,FileFd::WriteAny);
+   if (_error->PendingError() == true)
+      return ERROR_NOT_FROM_SERVER;
+
+   FailFile = Queue->DestFile;
+   FailFile.c_str();   // Make sure we dont do a malloc in the signal handler
+   FailFd = File->Fd();
+   FailTime = Server->Date;
+
+   if (Server->InitHashes(*File) == false)
+   {
+      _error->Errno("read",_("Problem hashing file"));
+      return ERROR_NOT_FROM_SERVER;
+   }
+   if (Server->StartPos > 0)
+      Res.ResumePoint = Server->StartPos;
+
+   SetNonBlock(File->Fd(),true);
+   return FILE_IS_OPEN;
+}
+									/*}}}*/
+// ServerMethod::SigTerm - Handle a fatal signal			/*{{{*/
+// ---------------------------------------------------------------------
+/* This closes and timestamps the open file. This is neccessary to get
+   resume behavoir on user abort */
+void ServerMethod::SigTerm(int)
+{
+   if (FailFd == -1)
+      _exit(100);
+   close(FailFd);
+   
+   // Timestamp
+   struct utimbuf UBuf;
+   UBuf.actime = FailTime;
+   UBuf.modtime = FailTime;
+   utime(FailFile.c_str(),&UBuf);
+   
+   _exit(100);
+}
+									/*}}}*/
+// ServerMethod::Fetch - Fetch an item					/*{{{*/
+// ---------------------------------------------------------------------
+/* This adds an item to the pipeline. We keep the pipeline at a fixed
+   depth. */
+bool ServerMethod::Fetch(FetchItem *)
+{
+   if (Server == 0)
+      return true;
+
+   // Queue the requests
+   int Depth = -1;
+   for (FetchItem *I = Queue; I != 0 && Depth < (signed)PipelineDepth; 
+	I = I->Next, Depth++)
+   {
+      // If pipelining is disabled, we only queue 1 request
+      if (Server->Pipeline == false && Depth >= 0)
+	 break;
+      
+      // Make sure we stick with the same server
+      if (Server->Comp(I->Uri) == false)
+	 break;
+      if (QueueBack == I)
+      {
+	 QueueBack = I->Next;
+	 SendReq(I);
+	 continue;
+      }
+   }
+   
+   return true;
+};
+									/*}}}*/
+// ServerMethod::Loop - Main loop					/*{{{*/
+int ServerMethod::Loop()
+{
+   typedef vector<string> StringVector;
+   typedef vector<string>::iterator StringVectorIterator;
+   map<string, StringVector> Redirected;
+
+   signal(SIGTERM,SigTerm);
+   signal(SIGINT,SigTerm);
+   
+   Server = 0;
+   
+   int FailCounter = 0;
+   while (1)
+   {      
+      // We have no commands, wait for some to arrive
+      if (Queue == 0)
+      {
+	 if (WaitFd(STDIN_FILENO) == false)
+	    return 0;
+      }
+      
+      /* Run messages, we can accept 0 (no message) if we didn't
+         do a WaitFd above.. Otherwise the FD is closed. */
+      int Result = Run(true);
+      if (Result != -1 && (Result != 0 || Queue == 0))
+      {
+	 if(FailReason.empty() == false ||
+	    _config->FindB("Acquire::http::DependOnSTDIN", true) == true)
+	    return 100;
+	 else
+	    return 0;
+      }
+
+      if (Queue == 0)
+	 continue;
+      
+      // Connect to the server
+      if (Server == 0 || Server->Comp(Queue->Uri) == false)
+      {
+	 delete Server;
+	 Server = CreateServerState(Queue->Uri);
+      }
+      /* If the server has explicitly said this is the last connection
+         then we pre-emptively shut down the pipeline and tear down 
+	 the connection. This will speed up HTTP/1.0 servers a tad
+	 since we don't have to wait for the close sequence to
+         complete */
+      if (Server->Persistent == false)
+	 Server->Close();
+
+      // Reset the pipeline
+      if (Server->IsOpen() == false)
+	 QueueBack = Queue;
+
+      // Connnect to the host
+      if (Server->Open() == false)
+      {
+	 Fail(true);
+	 delete Server;
+	 Server = 0;
+	 continue;
+      }
+
+      // Fill the pipeline.
+      Fetch(0);
+      
+      // Fetch the next URL header data from the server.
+      switch (Server->RunHeaders(File))
+      {
+	 case ServerState::RUN_HEADERS_OK:
+	 break;
+	 
+	 // The header data is bad
+	 case ServerState::RUN_HEADERS_PARSE_ERROR:
+	 {
+	    _error->Error(_("Bad header data"));
+	    Fail(true);
+	    RotateDNS();
+	    continue;
+	 }
+	 
+	 // The server closed a connection during the header get..
+	 default:
+	 case ServerState::RUN_HEADERS_IO_ERROR:
+	 {
+	    FailCounter++;
+	    _error->Discard();
+	    Server->Close();
+	    Server->Pipeline = false;
+	    
+	    if (FailCounter >= 2)
+	    {
+	       Fail(_("Connection failed"),true);
+	       FailCounter = 0;
+	    }
+	    
+	    RotateDNS();
+	    continue;
+	 }
+      };
+
+      // Decide what to do.
+      FetchResult Res;
+      Res.Filename = Queue->DestFile;
+      switch (DealWithHeaders(Res))
+      {
+	 // Ok, the file is Open
+	 case FILE_IS_OPEN:
+	 {
+	    URIStart(Res);
+
+	    // Run the data
+	    bool Result = true;
+            if (Server->HaveContent)
+	       Result = Server->RunData(File);
+
+	    /* If the server is sending back sizeless responses then fill in
+	       the size now */
+	    if (Res.Size == 0)
+	       Res.Size = File->Size();
+	    
+	    // Close the file, destroy the FD object and timestamp it
+	    FailFd = -1;
+	    delete File;
+	    File = 0;
+	    
+	    // Timestamp
+	    struct utimbuf UBuf;
+	    time(&UBuf.actime);
+	    UBuf.actime = Server->Date;
+	    UBuf.modtime = Server->Date;
+	    utime(Queue->DestFile.c_str(),&UBuf);
+
+	    // Send status to APT
+	    if (Result == true)
+	    {
+	       Res.TakeHashes(*Server->GetHashes());
+	       URIDone(Res);
+	    }
+	    else
+	    {
+	       if (Server->IsOpen() == false)
+	       {
+		  FailCounter++;
+		  _error->Discard();
+		  Server->Close();
+		  
+		  if (FailCounter >= 2)
+		  {
+		     Fail(_("Connection failed"),true);
+		     FailCounter = 0;
+		  }
+		  
+		  QueueBack = Queue;
+	       }
+	       else
+		  Fail(true);
+	    }
+	    break;
+	 }
+	 
+	 // IMS hit
+	 case IMS_HIT:
+	 {
+	    URIDone(Res);
+	    break;
+	 }
+	 
+	 // Hard server error, not found or something
+	 case ERROR_UNRECOVERABLE:
+	 {
+	    Fail();
+	    break;
+	 }
+	  
+	 // Hard internal error, kill the connection and fail
+	 case ERROR_NOT_FROM_SERVER:
+	 {
+	    delete File;
+	    File = 0;
+
+	    Fail();
+	    RotateDNS();
+	    Server->Close();
+	    break;
+	 }
+
+	 // We need to flush the data, the header is like a 404 w/ error text
+	 case ERROR_WITH_CONTENT_PAGE:
+	 {
+	    Fail();
+	    
+	    // Send to content to dev/null
+	    File = new FileFd("/dev/null",FileFd::WriteExists);
+	    Server->RunData(File);
+	    delete File;
+	    File = 0;
+	    break;
+	 }
+	 
+         // Try again with a new URL
+         case TRY_AGAIN_OR_REDIRECT:
+         {
+            // Clear rest of response if there is content
+            if (Server->HaveContent)
+            {
+               File = new FileFd("/dev/null",FileFd::WriteExists);
+               Server->RunData(File);
+               delete File;
+               File = 0;
+            }
+
+            /* Detect redirect loops.  No more redirects are allowed
+               after the same URI is seen twice in a queue item. */
+            StringVector &R = Redirected[Queue->DestFile];
+            bool StopRedirects = false;
+            if (R.empty() == true)
+               R.push_back(Queue->Uri);
+            else if (R[0] == "STOP" || R.size() > 10)
+               StopRedirects = true;
+            else
+            {
+               for (StringVectorIterator I = R.begin(); I != R.end(); ++I)
+                  if (Queue->Uri == *I)
+                  {
+                     R[0] = "STOP";
+                     break;
+                  }
+ 
+               R.push_back(Queue->Uri);
+            }
+ 
+            if (StopRedirects == false)
+               Redirect(NextURI);
+            else
+               Fail();
+ 
+            break;
+         }
+
+	 default:
+	 Fail(_("Internal error"));
+	 break;
+      }
+      
+      FailCounter = 0;
+   }
+   
+   return 0;
+}
+									/*}}}*/