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Diffstat (limited to 'methods/server.cc')
| -rw-r--r-- | methods/server.cc | 838 |
1 files changed, 838 insertions, 0 deletions
diff --git a/methods/server.cc b/methods/server.cc new file mode 100644 index 000000000..0408dddfd --- /dev/null +++ b/methods/server.cc @@ -0,0 +1,838 @@ +// -*- 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/configuration.h> +#include <apt-pkg/error.h> +#include <apt-pkg/fileutl.h> +#include <apt-pkg/strutl.h> + +#include <ctype.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/stat.h> +#include <sys/time.h> +#include <time.h> +#include <unistd.h> +#include <iostream> +#include <limits> +#include <map> +#include <string> +#include <vector> + +#include "server.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, + const std::string &Uri) +{ + Reset(false); + Owner->Status(_("Waiting for headers")); + + do + { + string Data; + if (ReadHeaderLines(Data) == false) + continue; + + if (Owner->Debug == true) + clog << "Answer for: " << Uri << endl << 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 persistence 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; + + if (Line.size() > 4 && stringcasecmp(Line.data(), Line.data()+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 != NULL && Owner->Debug == true) + clog << "HTTP server doesn't give Reason-Phrase for " << std::to_string(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 persistence + state. */ + if (Major < 1) + Persistent = false; + else + { + if (Major == 1 && Minor == 0) + { + Persistent = false; + } + else + { + Persistent = true; + if (PipelineAllowed) + Pipeline = true; + } + } + + return true; + } + + // Blah, some servers use "connection:closes", evil. + // and some even send empty header fields… + string::size_type Pos = Line.find(':'); + if (Pos == string::npos) + 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_ascii(Line[Pos2]) != 0) + Pos2++; + + string const Tag(Line,0,Pos); + string const Val(Line,Pos2); + + if (stringcasecmp(Tag,"Content-Length:") == 0) + { + if (Encoding == Closes) + Encoding = Stream; + HaveContent = true; + + unsigned long long * DownloadSizePtr = &DownloadSize; + if (Result == 416 || (Result >= 300 && Result < 400)) + DownloadSizePtr = &JunkSize; + + *DownloadSizePtr = strtoull(Val.c_str(), NULL, 10); + if (*DownloadSizePtr >= std::numeric_limits<unsigned long long>::max()) + return _error->Errno("HeaderLine", _("The HTTP server sent an invalid Content-Length header")); + else if (*DownloadSizePtr == 0) + HaveContent = false; + + // On partial content (206) the Content-Length less than the real + // size, so do not set it here but leave that to the Content-Range + // header instead + if(Result != 206 && TotalFileSize == 0) + TotalFileSize = DownloadSize; + + 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",&TotalFileSize) == 1) + ; // we got the expected filesize which is all we wanted + else if (sscanf(Val.c_str(),"bytes %llu-%*u/%llu",&StartPos,&TotalFileSize) != 2) + return _error->Error(_("The HTTP server sent an invalid Content-Range header")); + if ((unsigned long long)StartPos > TotalFileSize) + return _error->Error(_("This HTTP server has broken range support")); + + // figure out what we will download + DownloadSize = TotalFileSize - StartPos; + 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; + Pipeline = false; + /* Some servers send error pages (as they are dynamically generated) + for simplicity via a connection close instead of e.g. chunked, + so assuming an always closing server only if we get a file + close */ + if (Result >= 200 && Result < 300) + PipelineAllowed = false; + } + else 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; + } + + if (stringcasecmp(Tag, "Accept-Ranges:") == 0) + { + std::string ranges = ',' + Val + ','; + ranges.erase(std::remove(ranges.begin(), ranges.end(), ' '), ranges.end()); + if (ranges.find(",bytes,") == std::string::npos) + RangesAllowed = false; + return true; + } + + return true; +} + /*}}}*/ +// ServerState::ServerState - Constructor /*{{{*/ +ServerState::ServerState(URI Srv, ServerMethod *Owner) : + DownloadSize(0), ServerName(Srv), TimeOut(120), Owner(Owner) +{ + Reset(); +} + /*}}}*/ +bool ServerState::AddPartialFileToHashes(FileFd &File) /*{{{*/ +{ + File.Truncate(StartPos); + return GetHashes()->AddFD(File, StartPos); +} + /*}}}*/ +void ServerState::Reset(bool const Everything) /*{{{*/ +{ + Major = 0; Minor = 0; Result = 0; Code[0] = '\0'; + TotalFileSize = 0; JunkSize = 0; StartPos = 0; + Encoding = Closes; time(&Date); HaveContent = false; + State = Header; MaximumSize = 0; + if (Everything) + { + Persistent = false; Pipeline = false; PipelineAllowed = true; + RangesAllowed = true; + } +} + /*}}}*/ + +// 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) + { + RemoveFile("server", Queue->DestFile); + Res.IMSHit = true; + Res.LastModified = Queue->LastModified; + Res.Size = 0; + 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)); + if (Queue->Uri == NextURI) + { + SetFailReason("RedirectionLoop"); + _error->Error("Redirection loop encountered"); + if (Server->HaveContent == true) + return ERROR_WITH_CONTENT_PAGE; + return ERROR_UNRECOVERABLE; + } + return TRY_AGAIN_OR_REDIRECT; + } + else + { + NextURI = DeQuoteString(Server->Location); + URI tmpURI = NextURI; + if (tmpURI.Access.find('+') != std::string::npos) + { + _error->Error("Server tried to trick us into using a specific implementation: %s", tmpURI.Access.c_str()); + if (Server->HaveContent == true) + return ERROR_WITH_CONTENT_PAGE; + return ERROR_UNRECOVERABLE; + } + URI Uri = Queue->Uri; + if (Binary.find('+') != std::string::npos) + { + auto base = Binary.substr(0, Binary.find('+')); + if (base != tmpURI.Access) + { + tmpURI.Access = base + '+' + tmpURI.Access; + if (tmpURI.Access == Binary) + { + std::string tmpAccess = Uri.Access; + std::swap(tmpURI.Access, Uri.Access); + NextURI = tmpURI; + std::swap(tmpURI.Access, Uri.Access); + } + else + NextURI = tmpURI; + } + } + if (Queue->Uri == NextURI) + { + SetFailReason("RedirectionLoop"); + _error->Error("Redirection loop encountered"); + if (Server->HaveContent == true) + return ERROR_WITH_CONTENT_PAGE; + return ERROR_UNRECOVERABLE; + } + Uri.Access = Binary; + // same protocol redirects are okay + if (tmpURI.Access == Uri.Access) + return TRY_AGAIN_OR_REDIRECT; + // as well as http to https + else if ((Uri.Access == "http" || Uri.Access == "https+http") && tmpURI.Access == "https") + return TRY_AGAIN_OR_REDIRECT; + else + { + auto const tmpplus = tmpURI.Access.find('+'); + if (tmpplus != std::string::npos && tmpURI.Access.substr(tmpplus + 1) == "https") + { + auto const uriplus = Uri.Access.find('+'); + if (uriplus == std::string::npos) + { + if (Uri.Access == tmpURI.Access.substr(0, tmpplus)) // foo -> foo+https + return TRY_AGAIN_OR_REDIRECT; + } + else if (Uri.Access.substr(uriplus + 1) == "http" && + Uri.Access.substr(0, uriplus) == tmpURI.Access.substr(0, tmpplus)) // foo+http -> foo+https + return TRY_AGAIN_OR_REDIRECT; + } + } + _error->Error("Redirection from %s to '%s' is forbidden", Uri.Access.c_str(), NextURI.c_str()); + } + /* 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) + { + bool partialHit = false; + if (Queue->ExpectedHashes.usable() == true) + { + Hashes resultHashes(Queue->ExpectedHashes); + FileFd file(Queue->DestFile, FileFd::ReadOnly); + Server->TotalFileSize = file.FileSize(); + Server->Date = file.ModificationTime(); + resultHashes.AddFD(file); + HashStringList const hashList = resultHashes.GetHashStringList(); + partialHit = (Queue->ExpectedHashes == hashList); + } + else if ((unsigned long long)SBuf.st_size == Server->TotalFileSize) + partialHit = true; + if (partialHit == true) + { + // the file is completely downloaded, but was not moved + if (Server->HaveContent == true) + { + // nuke the sent error page + Server->RunDataToDevNull(); + Server->HaveContent = false; + } + Server->StartPos = Server->TotalFileSize; + Server->Result = 200; + } + else if (RemoveFile("server", Queue->DestFile)) + { + NextURI = Queue->Uri; + return TRY_AGAIN_OR_REDIRECT; + } + } + } + + /* We have a reply we don't handle. This should indicate a perm server + failure */ + if (Server->Result < 200 || Server->Result >= 300) + { + if (_error->PendingError() == false) + { + std::string err; + strprintf(err, "HttpError%u", 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->TotalFileSize; + return FILE_IS_OPEN; +} + /*}}}*/ +// ServerMethod::SigTerm - Handle a fatal signal /*{{{*/ +// --------------------------------------------------------------------- +/* This closes and timestamps the open file. This is necessary to get + resume behavoir on user abort */ +void ServerMethod::SigTerm(int) +{ + if (FailFd == -1) + _exit(100); + + struct timeval times[2]; + times[0].tv_sec = FailTime; + times[1].tv_sec = FailTime; + times[0].tv_usec = times[1].tv_usec = 0; + utimes(FailFile.c_str(), times); + close(FailFd); + + _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 == nullptr || QueueBack == nullptr) + return true; + + // If pipelining is disabled, we only queue 1 request + auto const AllowedDepth = Server->Pipeline ? PipelineDepth : 0; + // how deep is our pipeline currently? + decltype(PipelineDepth) CurrentDepth = 0; + for (FetchItem const *I = Queue; I != QueueBack; I = I->Next) + ++CurrentDepth; + if (CurrentDepth > AllowedDepth) + return true; + + do { + // Make sure we stick with the same server + if (Server->Comp(QueueBack->Uri) == false) + break; + + bool const UsableHashes = QueueBack->ExpectedHashes.usable(); + // if we have no hashes, do at most one such request + // as we can't fixup pipeling misbehaviors otherwise + if (CurrentDepth != 0 && UsableHashes == false) + break; + + if (UsableHashes && FileExists(QueueBack->DestFile)) + { + FileFd partial(QueueBack->DestFile, FileFd::ReadOnly); + Hashes wehave(QueueBack->ExpectedHashes); + if (QueueBack->ExpectedHashes.FileSize() == partial.FileSize()) + { + if (wehave.AddFD(partial) && + wehave.GetHashStringList() == QueueBack->ExpectedHashes) + { + FetchResult Res; + Res.Filename = QueueBack->DestFile; + Res.ResumePoint = QueueBack->ExpectedHashes.FileSize(); + URIStart(Res); + // move item to the start of the queue as URIDone will + // always dequeued the first item in the queue + if (Queue != QueueBack) + { + FetchItem *Prev = Queue; + for (; Prev->Next != QueueBack; Prev = Prev->Next) + /* look for the previous queue item */; + Prev->Next = QueueBack->Next; + QueueBack->Next = Queue; + Queue = QueueBack; + QueueBack = Prev->Next; + } + Res.TakeHashes(wehave); + URIDone(Res); + continue; + } + else + RemoveFile("Fetch-Partial", QueueBack->DestFile); + } + } + auto const Tmp = QueueBack; + QueueBack = QueueBack->Next; + SendReq(Tmp); + ++CurrentDepth; + } while (CurrentDepth <= AllowedDepth && QueueBack != nullptr); + + return true; +} + /*}}}*/ +// ServerMethod::Loop - Main loop /*{{{*/ +int ServerMethod::Loop() +{ + 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 || + ConfigFindB("DependOnSTDIN", true) == true) + return 100; + else + return 0; + } + + if (Queue == 0) + continue; + + // Connect to the server + if (Server == 0 || Server->Comp(Queue->Uri) == false) + { + Server = CreateServerState(Queue->Uri); + setPostfixForMethodNames(::URI(Queue->Uri).Host.c_str()); + AllowRedirect = ConfigFindB("AllowRedirect", true); + PipelineDepth = ConfigFindI("Pipeline-Depth", 10); + Debug = DebugEnabled(); + } + + /* 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); + Server = nullptr; + continue; + } + + // Fill the pipeline. + Fetch(0); + + // Fetch the next URL header data from the server. + switch (Server->RunHeaders(File, Queue->Uri)) + { + case ServerState::RUN_HEADERS_OK: + break; + + // The header data is bad + case ServerState::RUN_HEADERS_PARSE_ERROR: + { + _error->Error(_("Bad header data")); + Fail(true); + Server->Close(); + 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; + Server->PipelineAllowed = 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; + + // ensure we don't fetch too much + // we could do "Server->MaximumSize = Queue->MaximumSize" here + // but that would break the clever pipeline messup detection + // so instead we use the size of the biggest item in the queue + Server->MaximumSize = FindMaximumObjectSizeInQueue(); + + 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 timeval times[2]; + times[0].tv_sec = times[1].tv_sec = Server->Date; + times[0].tv_usec = times[1].tv_usec = 0; + utimes(Queue->DestFile.c_str(), times); + + // Send status to APT + if (Result == true) + { + Hashes * const resultHashes = Server->GetHashes(); + HashStringList const hashList = resultHashes->GetHashStringList(); + if (PipelineDepth != 0 && Queue->ExpectedHashes.usable() == true && Queue->ExpectedHashes != hashList) + { + // we did not get the expected hash… mhhh: + // could it be that server/proxy messed up pipelining? + FetchItem * BeforeI = Queue; + for (FetchItem *I = Queue->Next; I != 0 && I != QueueBack; I = I->Next) + { + if (I->ExpectedHashes.usable() == true && I->ExpectedHashes == hashList) + { + // yes, he did! Disable pipelining and rewrite queue + if (Server->Pipeline == true) + { + Warning(_("Automatically disabled %s due to incorrect response from server/proxy. (man 5 apt.conf)"), "Acquire::http::Pipeline-Depth"); + Server->Pipeline = false; + Server->PipelineAllowed = false; + // we keep the PipelineDepth value so that the rest of the queue can be fixed up as well + } + Rename(Res.Filename, I->DestFile); + Res.Filename = I->DestFile; + BeforeI->Next = I->Next; + I->Next = Queue; + Queue = I; + break; + } + BeforeI = I; + } + } + Res.TakeHashes(*resultHashes); + URIDone(Res); + } + else + { + if (Server->IsOpen() == false) + { + FailCounter++; + _error->Discard(); + Server->Close(); + + if (FailCounter >= 2) + { + Fail(_("Connection failed"),true); + FailCounter = 0; + } + + QueueBack = Queue; + } + else + { + Server->Close(); + 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: + { + Server->RunDataToDevNull(); + Fail(); + break; + } + + // Try again with a new URL + case TRY_AGAIN_OR_REDIRECT: + { + // Clear rest of response if there is content + if (Server->HaveContent) + Server->RunDataToDevNull(); + Redirect(NextURI); + break; + } + + default: + Fail(_("Internal error")); + break; + } + + FailCounter = 0; + } + + return 0; +} + /*}}}*/ +unsigned long long ServerMethod::FindMaximumObjectSizeInQueue() const /*{{{*/ +{ + unsigned long long MaxSizeInQueue = 0; + for (FetchItem *I = Queue; I != 0 && I != QueueBack; I = I->Next) + MaxSizeInQueue = std::max(MaxSizeInQueue, I->MaximumSize); + return MaxSizeInQueue; +} + /*}}}*/ +ServerMethod::ServerMethod(std::string &&Binary, char const * const Ver,unsigned long const Flags) :/*{{{*/ + aptMethod(std::move(Binary), Ver, Flags), Server(nullptr), File(NULL), PipelineDepth(10), + AllowRedirect(false), Debug(false) +{ +} + /*}}}*/ +bool ServerMethod::Configuration(std::string Message) /*{{{*/ +{ + if (aptMethod::Configuration(Message) == false) + return false; + + _config->CndSet("Acquire::tor::Proxy", + "socks5h://apt-transport-tor@localhost:9050"); + return true; +} + /*}}}*/ +bool ServerMethod::AddProxyAuth(URI &Proxy, URI const &Server) const /*{{{*/ +{ + if (std::find(methodNames.begin(), methodNames.end(), "tor") != methodNames.end() && + Proxy.User == "apt-transport-tor" && Proxy.Password.empty()) + { + std::string pass = Server.Host; + pass.erase(std::remove_if(pass.begin(), pass.end(), [](char const c) { return std::isalnum(c) == 0; }), pass.end()); + if (pass.length() > 255) + Proxy.Password = pass.substr(0, 255); + else + Proxy.Password = std::move(pass); + } + // FIXME: should we support auth.conf for proxies? + return true; +} + /*}}}*/ |