dispose http(s) 416 error page as non-content

Real webservers (like apache) actually send an error page with a 416
response, but our client didn't expect it leaving the page on the socket
to be parsed as response for the next request (http) or as file content
(https), which isn't what we want at all… Symptom is a "Bad header line"
as html usually doesn't parse that well to an http-header.

This manifests itself e.g. if we have a complete file (or larger) in
partial/ which isn't discarded by If-Range as the server doesn't support
it (or it is just newer, think: mirror rotation).
It is a sort-of regression of 78c72d0ce22e00b194251445aae306df357d5c1a,
which removed the filesize - 1 trick, but this had its own problems…

To properly test this our webserver gains the ability to reply with
transfer-encoding: chunked as most real webservers will use it to send
the dynamically generated error pages.

Closes: 768797

8 files changed, 233 insertions, 105 deletions

diff --git a/cmdline/apt-helper.cc b/cmdline/apt-helper.cc
index 1b832f165..a05ae90a2 100644
--- a/cmdline/apt-helper.cc
+++ b/cmdline/apt-helper.cc
@@ -51,22 +51,33 @@ static bool DoDownloadFile(CommandLine &CmdL)
    AcqTextStatus Stat(ScreenWidth, _config->FindI("quiet",0));
    pkgAcquire Fetcher(&Stat);
 
-   std::string download_uri = CmdL.FileList[1];
-   std::string targetfile = CmdL.FileList[2];
-   std::string hash;
-   if (CmdL.FileSize() > 3)
-      hash = CmdL.FileList[3];
-   // we use download_uri as descr and targetfile as short-descr
-   new pkgAcqFile(&Fetcher, download_uri, hash, 0, download_uri, targetfile, 
-                  "dest-dir-ignored", targetfile);
+   size_t fileind = 0;
+   std::vector<std::string> targetfiles;
+   while (fileind + 2 <= CmdL.FileSize())
+   {
+      std::string download_uri = CmdL.FileList[fileind + 1];
+      std::string targetfile = CmdL.FileList[fileind + 2];
+      std::string hash;
+      if (CmdL.FileSize() > fileind + 3)
+	 hash = CmdL.FileList[fileind + 3];
+      // we use download_uri as descr and targetfile as short-descr
+      new pkgAcqFile(&Fetcher, download_uri, hash, 0, download_uri, targetfile,
+	    "dest-dir-ignored", targetfile);
+      targetfiles.push_back(targetfile);
+      fileind += 3;
+   }
 
    // Disable drop-privs if "_apt" can not write to the target dir
    CheckDropPrivsMustBeDisabled(Fetcher);
 
    bool Failed = false;
-   if (AcquireRun(Fetcher, 0, &Failed, NULL) == false || Failed == true ||
-	 FileExists(targetfile) == false)
+   if (AcquireRun(Fetcher, 0, &Failed, NULL) == false || Failed == true)
       return _error->Error(_("Download Failed"));
+   if (targetfiles.empty() == false)
+      for (std::vector<std::string>::const_iterator f = targetfiles.begin(); f != targetfiles.end(); ++f)
+	 if (FileExists(*f) == false)
+	    return _error->Error(_("Download Failed"));
+
    return true;
 }
 
diff --git a/methods/http.cc b/methods/http.cc
index a5de13511..ad1347d36 100644
--- a/methods/http.cc
+++ b/methods/http.cc
@@ -444,6 +444,8 @@ bool HttpServerState::RunData(FileFd * const File)
          loss of the connection means we are done */
       if (Encoding == Closes)
 	 In.Limit(-1);
+      else if (JunkSize != 0)
+	 In.Limit(JunkSize);
       else
 	 In.Limit(Size - StartPos);
       
diff --git a/methods/https.cc b/methods/https.cc
index 366148e19..23b3a10d4 100644
--- a/methods/https.cc
+++ b/methods/https.cc
@@ -69,6 +69,9 @@ HttpsMethod::parse_header(void *buffer, size_t size, size_t nmemb, void *userp)
       {
          me->Server->Result = 200;
 	 me->Server->StartPos = me->Server->Size;
+	 // the actual size is not important for https as curl will deal with it
+	 // by itself and e.g. doesn't bother us with transport-encoding…
+	 me->Server->JunkSize = std::numeric_limits<unsigned long long>::max();
       }
       else
 	 me->Server->StartPos = 0;
@@ -86,19 +89,25 @@ size_t
 HttpsMethod::write_data(void *buffer, size_t size, size_t nmemb, void *userp)
 {
    HttpsMethod *me = (HttpsMethod *)userp;
+   size_t buffer_size = size * nmemb;
+   // we don't need to count the junk here, just drop anything we get as
+   // we don't always know how long it would be, e.g. in chunked encoding.
+   if (me->Server->JunkSize != 0)
+      return buffer_size;
 
    if (me->Res.Size == 0)
       me->URIStart(me->Res);
-   if(me->File->Write(buffer, size*nmemb) != true)
+   if(me->File->Write(buffer, buffer_size) != true)
       return false;
 
    if(me->Queue->MaximumSize > 0 && me->File->Tell() > me->Queue->MaximumSize)
    {
       me->SetFailReason("MaximumSizeExceeded");
-      return _error->Error("Writing more data than expected (%llu > %llu)",
+      _error->Error("Writing more data than expected (%llu > %llu)",
                            me->TotalWritten, me->Queue->MaximumSize);
+      return 0;
    }
-   return size*nmemb;
+   return buffer_size;
 }
 
 int
diff --git a/methods/server.cc b/methods/server.cc
index c4689ff12..9b3d39cf2 100644
--- a/methods/server.cc
+++ b/methods/server.cc
@@ -55,6 +55,7 @@ ServerState::RunHeadersResult ServerState::RunHeaders(FileFd * const File,
    Minor = 0; 
    Result = 0; 
    Size = 0; 
+   JunkSize = 0;
    StartPos = 0;
    Encoding = Closes;
    HaveContent = false;
@@ -163,14 +164,14 @@ bool ServerState::HeaderLine(string Line)
 	 Encoding = Stream;
       HaveContent = true;
 
-      // The length is already set from the Content-Range header
-      if (StartPos != 0)
-	 return true;
+      unsigned long long * SizePtr = &Size;
+      if (Result == 416)
+	 SizePtr = &JunkSize;
 
-      Size = strtoull(Val.c_str(), NULL, 10);
-      if (Size >= std::numeric_limits<unsigned long long>::max())
+      *SizePtr = strtoull(Val.c_str(), NULL, 10);
+      if (*SizePtr >= std::numeric_limits<unsigned long long>::max())
 	 return _error->Errno("HeaderLine", _("The HTTP server sent an invalid Content-Length header"));
-      else if (Size == 0)
+      else if (*SizePtr == 0)
 	 HaveContent = false;
       return true;
    }
@@ -187,10 +188,7 @@ bool ServerState::HeaderLine(string Line)
 
       // §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;
-      }
+	 ; // we got the expected filesize which is all we wanted
       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)
@@ -308,9 +306,15 @@ ServerMethod::DealWithHeaders(FetchResult &Res)
 	 if ((unsigned long long)SBuf.st_size == Server->Size)
 	 {
 	    // the file is completely downloaded, but was not moved
+	    if (Server->HaveContent == true)
+	    {
+	       // Send to error page to dev/null
+	       FileFd DevNull("/dev/null",FileFd::WriteExists);
+	       Server->RunData(&DevNull);
+	    }
+	    Server->HaveContent = false;
 	    Server->StartPos = Server->Size;
 	    Server->Result = 200;
-	    Server->HaveContent = false;
 	 }
 	 else if (unlink(Queue->DestFile.c_str()) == 0)
 	 {
diff --git a/methods/server.h b/methods/server.h
index 7d5198478..b974ec89a 100644
--- a/methods/server.h
+++ b/methods/server.h
@@ -34,7 +34,8 @@ struct ServerState
    char Code[360];
 
    // These are some statistics from the last parsed header lines
-   unsigned long long Size;
+   unsigned long long Size; // size of the usable content (aka: the file)
+   unsigned long long JunkSize; // size of junk content (aka: server error pages)
    unsigned long long StartPos;
    time_t Date;
    bool HaveContent;
@@ -73,7 +74,7 @@ struct ServerState
    RunHeadersResult RunHeaders(FileFd * const File, const std::string &Uri);
 
    bool Comp(URI Other) const {return Other.Host == ServerName.Host && Other.Port == ServerName.Port;};
-   virtual void Reset() {Major = 0; Minor = 0; Result = 0; Code[0] = '\0'; Size = 0;
+   virtual void Reset() {Major = 0; Minor = 0; Result = 0; Code[0] = '\0'; Size = 0; JunkSize = 0;
 		 StartPos = 0; Encoding = Closes; time(&Date); HaveContent = false;
 		 State = Header; Persistent = false; Pipeline = true; MaximumSize = 0;};
    virtual bool WriteResponse(std::string const &Data) = 0;
diff --git a/test/integration/framework b/test/integration/framework
index 930ab9367..f7f69f5d5 100644
--- a/test/integration/framework
+++ b/test/integration/framework
@@ -1119,8 +1119,8 @@ acquire::cdrom::autodetect 0;" > rootdir/etc/apt/apt.conf.d/00cdrom
 }
 
 downloadfile() {
-	local PROTO="$(echo "$1" | cut -d':' -f 1 )"
-	apthelper -o Debug::Acquire::${PROTO}=1 \
+	local PROTO="${1%%:*}"
+	apthelper -o Debug::Acquire::${PROTO}=1 -o Debug::pkgAcquire::Worker=1 \
 		download-file "$1" "$2" 2>&1 || true
 	# only if the file exists the download was successful
 	if [ -r "$2" ]; then
diff --git a/test/integration/test-partial-file-support b/test/integration/test-partial-file-support
index 98b2f242a..b6b305d25 100755
--- a/test/integration/test-partial-file-support
+++ b/test/integration/test-partial-file-support
@@ -24,13 +24,25 @@ testdownloadfile() {
 	else
 		msgpass
 	fi
-	cat "$DOWNLOADLOG" | while read field hash; do
+	sed -e '/^ <- / s#%20# #g' -e '/^ <- / s#%0a#\n#g' "$DOWNLOADLOG" | grep '^.*-Hash: ' > receivedhashes.log
+	testsuccess test -s receivedhashes.log
+	local HASHES_OK=0
+	local HASHES_BAD=0
+	while read field hash; do
 		local EXPECTED
 		case "$field" in
 		'MD5Sum-Hash:') EXPECTED="$(md5sum "$TESTFILE" | cut -d' ' -f 1)";;
 		'SHA1-Hash:') EXPECTED="$(sha1sum "$TESTFILE" | cut -d' ' -f 1)";;
 		'SHA256-Hash:') EXPECTED="$(sha256sum "$TESTFILE" | cut -d' ' -f 1)";;
 		'SHA512-Hash:') EXPECTED="$(sha512sum "$TESTFILE" | cut -d' ' -f 1)";;
+		'Checksum-FileSize-Hash:')
+			#filesize is too weak to check for !=
+			if [ "$4" = '=' ]; then
+				EXPECTED="$(stat -c '%s' "$TESTFILE")"
+			else
+				continue
+			fi
+			;;
 		*) continue;;
 		esac
 		if [ "$4" = '=' ]; then
@@ -40,15 +52,41 @@ testdownloadfile() {
 		fi
 		if [ "$EXPECTED" "$4" "$hash" ]; then
 			msgpass
+			HASHES_OK=$((HASHES_OK+1));
 		else
-			cat >&2 "$DOWNLOADLOG"
 			msgfail "expected: $EXPECTED ; got: $hash"
+			HASHES_BAD=$((HASHES_BAD+1));
 		fi
-	done
+	done < receivedhashes.log
+	msgtest 'At least one good hash and no bad ones'
+	if [ $HASHES_OK -eq 0 ] || [ $HASHES_BAD -ne 0 ]; then
+		cat >&2 "$DOWNLOADLOG"
+		msgfail
+	else
+		msgpass
+	fi
 }
 
 TESTFILE='aptarchive/testfile'
 cp -a ${TESTDIR}/framework $TESTFILE
+cp -a ${TESTDIR}/framework "${TESTFILE}2"
+
+followuprequest() {
+	local DOWN='./downloaded/testfile'
+
+	copysource $TESTFILE 1M $DOWN
+	testdownloadfile 'completely downloaded file' "${1}/testfile" "$DOWN" '='
+	testwebserverlaststatuscode '416' "$DOWNLOADLOG"
+
+	copysource $TESTFILE 1M $DOWN
+	copysource "${TESTFILE}2" 20 "${DOWN}2"
+	msgtest 'Testing download of files with' 'completely downloaded file + partial file'
+	testsuccess --nomsg apthelper -o Debug::Acquire::${1%%:*}=1 -o Debug::pkgAcquire::Worker=1 \
+		download-file "$1/testfile" "$DOWN" '' "$1/testfile2" "${DOWN}2"
+	testwebserverlaststatuscode '206' 'rootdir/tmp/testsuccess.output'
+	testsuccess diff -u "$TESTFILE" "${DOWN}"
+	testsuccess diff -u "${DOWN}" "${DOWN}2"
+}
 
 testrun() {
 	webserverconfig 'aptwebserver::support::range' 'true'
@@ -66,9 +104,11 @@ testrun() {
 	testdownloadfile 'invalid partial data' "${1}/testfile" "$DOWN" '!='
 	testwebserverlaststatuscode '206' "$DOWNLOADLOG"
 
-	copysource $TESTFILE 1M $DOWN
-	testdownloadfile 'completely downloaded file' "${1}/testfile" "$DOWN" '='
-	testwebserverlaststatuscode '416' "$DOWNLOADLOG"
+	webserverconfig 'aptwebserver::closeOnError' 'false'
+	followuprequest "$1"
+	webserverconfig 'aptwebserver::closeOnError' 'true'
+	followuprequest "$1"
+	webserverconfig 'aptwebserver::closeOnError' 'false'
 
 	copysource /dev/zero 1M $DOWN
 	testdownloadfile 'too-big partial file' "${1}/testfile" "$DOWN" '='
@@ -86,8 +126,18 @@ testrun() {
 	testwebserverlaststatuscode '200' "$DOWNLOADLOG"
 }
 
+msgmsg 'http: Test with Content-Length'
+webserverconfig 'aptwebserver::chunked-transfer-encoding' 'false'
+testrun 'http://localhost:8080'
+msgmsg 'http: Test with Transfer-Encoding: chunked'
+webserverconfig 'aptwebserver::chunked-transfer-encoding' 'true'
 testrun 'http://localhost:8080'
 
 changetohttpswebserver
 
+msgmsg 'https: Test with Content-Length'
+webserverconfig 'aptwebserver::chunked-transfer-encoding' 'false'
+testrun 'https://localhost:4433'
+msgmsg 'https: Test with Transfer-Encoding: chunked'
+webserverconfig 'aptwebserver::chunked-transfer-encoding' 'true'
 testrun 'https://localhost:4433'
diff --git a/test/interactive-helper/aptwebserver.cc b/test/interactive-helper/aptwebserver.cc
index 00004a524..ca6f88c58 100644
--- a/test/interactive-helper/aptwebserver.cc
+++ b/test/interactive-helper/aptwebserver.cc
@@ -19,6 +19,8 @@
 #include <sys/stat.h>
 #include <time.h>
 #include <unistd.h>
+
+#include <algorithm>
 #include <iostream>
 #include <sstream>
 #include <list>
@@ -79,12 +81,21 @@ static char const * httpcodeToStr(int const httpcode)		/*{{{*/
    return NULL;
 }
 									/*}}}*/
+static bool chunkedTransferEncoding(std::list<std::string> const &headers) {
+   if (std::find(headers.begin(), headers.end(), "Transfer-Encoding: chunked") != headers.end())
+      return true;
+   if (_config->FindB("aptwebserver::chunked-transfer-encoding", false) == true)
+      return true;
+   return false;
+}
 static void addFileHeaders(std::list<std::string> &headers, FileFd &data)/*{{{*/
 {
-   std::ostringstream contentlength;
-   contentlength << "Content-Length: " << data.FileSize();
-   headers.push_back(contentlength.str());
-
+   if (chunkedTransferEncoding(headers) == false)
+   {
+      std::ostringstream contentlength;
+      contentlength << "Content-Length: " << data.FileSize();
+      headers.push_back(contentlength.str());
+   }
    std::string lastmodified("Last-Modified: ");
    lastmodified.append(TimeRFC1123(data.ModificationTime()));
    headers.push_back(lastmodified);
@@ -92,9 +103,12 @@ static void addFileHeaders(std::list<std::string> &headers, FileFd &data)/*{{{*/
 									/*}}}*/
 static void addDataHeaders(std::list<std::string> &headers, std::string &data)/*{{{*/
 {
-   std::ostringstream contentlength;
-   contentlength << "Content-Length: " << data.size();
-   headers.push_back(contentlength.str());
+   if (chunkedTransferEncoding(headers) == false)
+   {
+      std::ostringstream contentlength;
+      contentlength << "Content-Length: " << data.size();
+      headers.push_back(contentlength.str());
+   }
 }
 									/*}}}*/
 static bool sendHead(int const client, int const httpcode, std::list<std::string> &headers)/*{{{*/
@@ -114,6 +128,9 @@ static bool sendHead(int const client, int const httpcode, std::list<std::string
    date.append(TimeRFC1123(time(NULL)));
    headers.push_back(date);
 
+   if (chunkedTransferEncoding(headers) == true)
+      headers.push_back("Transfer-Encoding: chunked");
+
    std::clog << ">>> RESPONSE to " << client << " >>>" << std::endl;
    bool Success = true;
    for (std::list<std::string>::const_iterator h = headers.begin();
@@ -130,25 +147,55 @@ static bool sendHead(int const client, int const httpcode, std::list<std::string
    return Success;
 }
 									/*}}}*/
-static bool sendFile(int const client, FileFd &data)			/*{{{*/
+static bool sendFile(int const client, std::list<std::string> const &headers, FileFd &data)/*{{{*/
 {
    bool Success = true;
+   bool const chunked = chunkedTransferEncoding(headers);
    char buffer[500];
    unsigned long long actual = 0;
    while ((Success &= data.Read(buffer, sizeof(buffer), &actual)) == true)
    {
       if (actual == 0)
 	 break;
-      Success &= FileFd::Write(client, buffer, actual);
+
+      if (chunked == true)
+      {
+	 std::string size;
+	 strprintf(size, "%llX\r\n", actual);
+	 Success &= FileFd::Write(client, size.c_str(), size.size());
+	 Success &= FileFd::Write(client, buffer, actual);
+	 Success &= FileFd::Write(client, "\r\n", strlen("\r\n"));
+      }
+      else
+	 Success &= FileFd::Write(client, buffer, actual);
+   }
+   if (chunked == true)
+   {
+      char const * const finish = "0\r\n\r\n";
+      Success &= FileFd::Write(client, finish, strlen(finish));
    }
    if (Success == false)
-      std::cerr << "SENDFILE: READ/WRITE ERROR to " << client << std::endl;
+      std::cerr << "SENDFILE:" << (chunked ? " CHUNKED" : "") << " READ/WRITE ERROR to " << client << std::endl;
    return Success;
 }
 									/*}}}*/
-static bool sendData(int const client, std::string const &data)		/*{{{*/
+static bool sendData(int const client, std::list<std::string> const &headers, std::string const &data)/*{{{*/
 {
-   if (FileFd::Write(client, data.c_str(), data.size()) == false)
+   if (chunkedTransferEncoding(headers) == true)
+   {
+      unsigned long long const ullsize = data.length();
+      std::string size;
+      strprintf(size, "%llX\r\n", ullsize);
+      char const * const finish = "\r\n0\r\n\r\n";
+      if (FileFd::Write(client, size.c_str(), size.length()) == false ||
+	    FileFd::Write(client, data.c_str(), ullsize) == false ||
+	    FileFd::Write(client, finish, strlen(finish)) == false)
+      {
+	 std::cerr << "SENDDATA: CHUNK WRITE ERROR to " << client << std::endl;
+	 return false;
+      }
+   }
+   else if (FileFd::Write(client, data.c_str(), data.size()) == false)
    {
       std::cerr << "SENDDATA: WRITE ERROR to " << client << std::endl;
       return false;
@@ -157,33 +204,38 @@ static bool sendData(int const client, std::string const &data)		/*{{{*/
 }
 									/*}}}*/
 static void sendError(int const client, int const httpcode, std::string const &request,/*{{{*/
-	       bool content, std::string const &error = "", std::list<std::string> headers = std::list<std::string>())
+	       bool const content, std::string const &error, std::list<std::string> &headers)
 {
    std::string response("<html><head><title>");
    response.append(httpcodeToStr(httpcode)).append("</title></head>");
    response.append("<body><h1>").append(httpcodeToStr(httpcode)).append("</h1>");
    if (httpcode != 200)
-   {
-      if (error.empty() == false)
-	 response.append("<p><em>Error</em>: ").append(error).append("</p>");
-      response.append("This error is a result of the request: <pre>");
-   }
+      response.append("<p><em>Error</em>: ");
+   else
+      response.append("<p><em>Success</em>: ");
+   if (error.empty() == false)
+      response.append(error);
+   else
+      response.append(httpcodeToStr(httpcode));
+   if (httpcode != 200)
+      response.append("</p>This error is a result of the request: <pre>");
    else
-   {
-      if (error.empty() == false)
-	 response.append("<p><em>Success</em>: ").append(error).append("</p>");
       response.append("The successfully executed operation was requested by: <pre>");
-   }
    response.append(request).append("</pre></body></html>");
+   if (httpcode != 200)
+   {
+      if (_config->FindB("aptwebserver::closeOnError", false) == true)
+	 headers.push_back("Connection: close");
+   }
    addDataHeaders(headers, response);
    sendHead(client, httpcode, headers);
    if (content == true)
-      sendData(client, response);
+      sendData(client, headers, response);
 }
 static void sendSuccess(int const client, std::string const &request,
-	       bool content, std::string const &error = "")
+	       bool const content, std::string const &error, std::list<std::string> &headers)
 {
-   sendError(client, 200, request, content, error);
+   sendError(client, 200, request, content, error, headers);
 }
 									/*}}}*/
 static void sendRedirect(int const client, int const httpcode, std::string const &uri,/*{{{*/
@@ -220,7 +272,7 @@ static void sendRedirect(int const client, int const httpcode, std::string const
    headers.push_back(location);
    sendHead(client, httpcode, headers);
    if (content == true)
-      sendData(client, response);
+      sendData(client, headers, response);
 }
 									/*}}}*/
 static int filter_hidden_files(const struct dirent *a)			/*{{{*/
@@ -262,16 +314,15 @@ static int grouped_alpha_case_sort(const struct dirent **a, const struct dirent
 }
 									/*}}}*/
 static void sendDirectoryListing(int const client, std::string const &dir,/*{{{*/
-			  std::string const &request, bool content)
+			  std::string const &request, bool content, std::list<std::string> &headers)
 {
-   std::list<std::string> headers;
    std::ostringstream listing;
 
    struct dirent **namelist;
    int const counter = scandir(dir.c_str(), &namelist, filter_hidden_files, grouped_alpha_case_sort);
    if (counter == -1)
    {
-      sendError(client, 500, request, content);
+      sendError(client, 500, request, content, "scandir failed", headers);
       return;
    }
 
@@ -310,18 +361,18 @@ static void sendDirectoryListing(int const client, std::string const &dir,/*{{{*
    addDataHeaders(headers, response);
    sendHead(client, 200, headers);
    if (content == true)
-      sendData(client, response);
+      sendData(client, headers, response);
 }
 									/*}}}*/
 static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
 		    std::string &filename, std::string &params, bool &sendContent,
-		    bool &closeConnection)
+		    bool &closeConnection, std::list<std::string> &headers)
 {
    if (strncmp(request.c_str(), "HEAD ", 5) == 0)
       sendContent = false;
    if (strncmp(request.c_str(), "GET ", 4) != 0)
    {
-      sendError(client, 501, request, true);
+      sendError(client, 501, request, true, "", headers);
       return false;
    }
 
@@ -332,7 +383,7 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
    if (lineend == std::string::npos || filestart == std::string::npos ||
 	 fileend == std::string::npos || filestart == fileend)
    {
-      sendError(client, 500, request, sendContent, "Filename can't be extracted");
+      sendError(client, 500, request, sendContent, "Filename can't be extracted", headers);
       return false;
    }
 
@@ -344,14 +395,14 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
       closeConnection = strcasecmp(LookupTag(request, "Connection", "Keep-Alive").c_str(), "close") == 0;
    else
    {
-      sendError(client, 500, request, sendContent, "Not a HTTP/1.{0,1} request");
+      sendError(client, 500, request, sendContent, "Not a HTTP/1.{0,1} request", headers);
       return false;
    }
 
    filename = request.substr(filestart, fileend - filestart);
    if (filename.find(' ') != std::string::npos)
    {
-      sendError(client, 500, request, sendContent, "Filename contains an unencoded space");
+      sendError(client, 500, request, sendContent, "Filename contains an unencoded space", headers);
       return false;
    }
 
@@ -359,7 +410,7 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
    if (host.empty() == true)
    {
       // RFC 2616 §14.23 requires Host
-      sendError(client, 400, request, sendContent, "Host header is required");
+      sendError(client, 400, request, sendContent, "Host header is required", headers);
       return false;
    }
    host = "http://" + host;
@@ -370,7 +421,7 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
    {
       if (absolute.find("uri") == std::string::npos)
       {
-	 sendError(client, 400, request, sendContent, "Request is absoluteURI, but configured to not accept that");
+	 sendError(client, 400, request, sendContent, "Request is absoluteURI, but configured to not accept that", headers);
 	 return false;
       }
 
@@ -382,9 +433,9 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
       if (authConf.empty() != auth.empty())
       {
 	 if (auth.empty())
-	    sendError(client, 407, request, sendContent, "Proxy requires authentication");
+	    sendError(client, 407, request, sendContent, "Proxy requires authentication", headers);
 	 else
-	    sendError(client, 407, request, sendContent, "Client wants to authenticate to proxy, but proxy doesn't need it");
+	    sendError(client, 407, request, sendContent, "Client wants to authenticate to proxy, but proxy doesn't need it", headers);
 	return false;
       }
       if (authConf.empty() == false)
@@ -395,7 +446,7 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
 	    auth.erase(0, strlen(basic));
 	    if (auth != authConf)
 	    {
-	       sendError(client, 407, request, sendContent, "Proxy-Authentication doesn't match");
+	       sendError(client, 407, request, sendContent, "Proxy-Authentication doesn't match", headers);
 	       return false;
 	    }
 	 }
@@ -410,7 +461,7 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
    }
    else if (absolute.find("path") == std::string::npos && APT::String::Startswith(filename, "/_config/") == false)
    {
-      sendError(client, 400, request, sendContent, "Request is absolutePath, but configured to not accept that");
+      sendError(client, 400, request, sendContent, "Request is absolutePath, but configured to not accept that", headers);
       return false;
    }
 
@@ -421,9 +472,9 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
       if (authConf.empty() != auth.empty())
       {
 	 if (auth.empty())
-	    sendError(client, 401, request, sendContent, "Server requires authentication");
+	    sendError(client, 401, request, sendContent, "Server requires authentication", headers);
 	 else
-	    sendError(client, 401, request, sendContent, "Client wants to authenticate to server, but server doesn't need it");
+	    sendError(client, 401, request, sendContent, "Client wants to authenticate to server, but server doesn't need it", headers);
 	 return false;
       }
       if (authConf.empty() == false)
@@ -434,13 +485,12 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
 	    auth.erase(0, strlen(basic));
 	    if (auth != authConf)
 	    {
-	       sendError(client, 401, request, sendContent, "Authentication doesn't match");
+	       sendError(client, 401, request, sendContent, "Authentication doesn't match", headers);
 	       return false;
 	    }
 	 }
 	 else
 	 {
-	    std::list<std::string> headers;
 	    headers.push_back("WWW-Authenticate: Basic");
 	    sendError(client, 401, request, sendContent, "Unsupported Authentication Scheme", headers);
 	    return false;
@@ -463,7 +513,8 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
        filename.find_first_of("\r\n\t\f\v") != std::string::npos ||
        filename.find("/../") != std::string::npos)
    {
-      sendError(client, 400, request, sendContent, "Filename contains illegal character (sequence)");
+      std::list<std::string> headers;
+      sendError(client, 400, request, sendContent, "Filename contains illegal character (sequence)", headers);
       return false;
    }
 
@@ -499,7 +550,8 @@ static bool parseFirstLine(int const client, std::string const &request,/*{{{*/
    return true;
 }
 									/*}}}*/
-static bool handleOnTheFlyReconfiguration(int const client, std::string const &request, std::vector<std::string> parts)/*{{{*/
+static bool handleOnTheFlyReconfiguration(int const client, std::string const &request,/*{{{*/
+      std::vector<std::string> parts, std::list<std::string> &headers)
 {
    size_t const pcount = parts.size();
    for (size_t i = 0; i < pcount; ++i)
@@ -507,40 +559,38 @@ static bool handleOnTheFlyReconfiguration(int const client, std::string const &r
    if (pcount == 4 && parts[1] == "set")
    {
       _config->Set(parts[2], parts[3]);
-      sendSuccess(client, request, true, "Option '" + parts[2] + "' was set to '" + parts[3] + "'!");
+      sendSuccess(client, request, true, "Option '" + parts[2] + "' was set to '" + parts[3] + "'!", headers);
       return true;
    }
    else if (pcount == 4 && parts[1] == "find")
    {
-      std::list<std::string> headers;
       std::string response = _config->Find(parts[2], parts[3]);
       addDataHeaders(headers, response);
       sendHead(client, 200, headers);
-      sendData(client, response);
+      sendData(client, headers, response);
       return true;
    }
    else if (pcount == 3 && parts[1] == "find")
    {
-      std::list<std::string> headers;
       if (_config->Exists(parts[2]) == true)
       {
 	 std::string response = _config->Find(parts[2]);
 	 addDataHeaders(headers, response);
 	 sendHead(client, 200, headers);
-	 sendData(client, response);
+	 sendData(client, headers, response);
 	 return true;
       }
-      sendError(client, 404, request, "Requested Configuration option doesn't exist.");
+      sendError(client, 404, request, true, "Requested Configuration option doesn't exist", headers);
       return false;
    }
    else if (pcount == 3 && parts[1] == "clear")
    {
       _config->Clear(parts[2]);
-      sendSuccess(client, request, true, "Option '" + parts[2] + "' was cleared.");
+      sendSuccess(client, request, true, "Option '" + parts[2] + "' was cleared.", headers);
       return true;
    }
 
-   sendError(client, 400, request, true, "Unknown on-the-fly configuration request");
+   sendError(client, 400, request, true, "Unknown on-the-fly configuration request", headers);
    return false;
 }
 									/*}}}*/
@@ -549,18 +599,22 @@ static void * handleClient(void * voidclient)				/*{{{*/
    int client = *((int*)(voidclient));
    std::clog << "ACCEPT client " << client << std::endl;
    std::vector<std::string> messages;
-   while (ReadMessages(client, messages))
+   bool closeConnection = false;
+   std::list<std::string> headers;
+   while (closeConnection == false && ReadMessages(client, messages))
    {
-      bool closeConnection = false;
+      // if we announced a closing, do the close
+      if (std::find(headers.begin(), headers.end(), std::string("Connection: close")) != headers.end())
+	 break;
+      headers.clear();
       for (std::vector<std::string>::const_iterator m = messages.begin();
 	    m != messages.end() && closeConnection == false; ++m) {
 	 std::clog << ">>> REQUEST from " << client << " >>>" << std::endl << *m
 	    << std::endl << "<<<<<<<<<<<<<<<<" << std::endl;
-	 std::list<std::string> headers;
 	 std::string filename;
 	 std::string params;
 	 bool sendContent = true;
-	 if (parseFirstLine(client, *m, filename, params, sendContent, closeConnection) == false)
+	 if (parseFirstLine(client, *m, filename, params, sendContent, closeConnection, headers) == false)
 	    continue;
 
 	 // special webserver command request
@@ -569,7 +623,7 @@ static void * handleClient(void * voidclient)				/*{{{*/
 	    std::vector<std::string> parts = VectorizeString(filename, '/');
 	    if (parts[0] == "_config")
 	    {
-	       handleOnTheFlyReconfiguration(client, *m, parts);
+	       handleOnTheFlyReconfiguration(client, *m, parts, headers);
 	       continue;
 	    }
 	 }
@@ -601,7 +655,7 @@ static void * handleClient(void * voidclient)				/*{{{*/
 	       {
 		  char error[300];
 		  regerror(res, pattern, error, sizeof(error));
-		  sendError(client, 500, *m, sendContent, error);
+		  sendError(client, 500, *m, sendContent, error, headers);
 		  continue;
 	       }
 	       if (regexec(pattern, filename.c_str(), 0, 0, 0) == 0)
@@ -620,7 +674,7 @@ static void * handleClient(void * voidclient)				/*{{{*/
 	 if (_config->FindB("aptwebserver::support::http", true) == false &&
 	       LookupTag(*m, "Host").find(":4433") == std::string::npos)
 	 {
-	    sendError(client, 400, *m, sendContent, "HTTP disabled, all requests must be HTTPS");
+	    sendError(client, 400, *m, sendContent, "HTTP disabled, all requests must be HTTPS", headers);
 	    continue;
 	 }
 	 else if (RealFileExists(filename) == true)
@@ -676,17 +730,16 @@ static void * handleClient(void * voidclient)				/*{{{*/
 			headers.push_back(contentrange.str());
 			sendHead(client, 206, headers);
 			if (sendContent == true)
-			   sendFile(client, data);
+			   sendFile(client, headers, data);
 			continue;
 		     }
 		     else
 		     {
-			headers.push_back("Content-Length: 0");
 			std::ostringstream contentrange;
 			contentrange << "Content-Range: bytes */" << filesize;
 			headers.push_back(contentrange.str());
-			sendHead(client, 416, headers);
-			continue;
+			sendError(client, 416, *m, sendContent, "", headers);
+			break;
 		     }
 		  }
 	       }
@@ -695,22 +748,20 @@ static void * handleClient(void * voidclient)				/*{{{*/
 	    addFileHeaders(headers, data);
 	    sendHead(client, 200, headers);
 	    if (sendContent == true)
-	       sendFile(client, data);
+	       sendFile(client, headers, data);
 	 }
 	 else if (DirectoryExists(filename) == true)
 	 {
 	    if (filename[filename.length()-1] == '/')
-	       sendDirectoryListing(client, filename, *m, sendContent);
+	       sendDirectoryListing(client, filename, *m, sendContent, headers);
 	    else
 	       sendRedirect(client, 301, filename.append("/"), *m, sendContent);
 	 }
 	 else
-	    sendError(client, 404, *m, sendContent);
+	    sendError(client, 404, *m, sendContent, "", headers);
       }
       _error->DumpErrors(std::cerr);
       messages.clear();
-      if (closeConnection == true)
-	 break;
    }
    close(client);
    std::clog << "CLOSE client " << client << std::endl;