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+// -*- mode: cpp; mode: fold -*-
+// Description /*{{{*/
+/* ######################################################################
+
+ RSH method - Transfer files via rsh compatible program
+
+ Written by Ben Collins <bcollins@debian.org>, Copyright (c) 2000
+
+ This file stated:
+ Licensed under the GNU General Public License v2 [no exception clauses]
+
+ We believe that this was intended to be not a statement against future
+ versions of the GPL, but meant to exclude the Qt license exception in
+ place in APT until that time.
+
+ We received permission from Ben in 2021 to relicense under GPL-2+,
+ contributions from Adam Heath and Daniel Hartwig may still have to
+ be considered GPL-2 for the time being.
+
+ Other contributions are GPL-2+
+
+ See https://lists.debian.org/deity/2021/04/msg00013.html for details
+
+ ##################################################################### */
+ /*}}}*/
+// Include Files /*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/strutl.h>
+
+#include "rsh.h"
+#include <cerrno>
+#include <csignal>
+#include <cstdarg>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+ /*}}}*/
+
+unsigned long TimeOut = 30;
+Configuration::Item const *RshOptions = 0;
+time_t RSHMethod::FailTime = 0;
+std::string RSHMethod::FailFile;
+int RSHMethod::FailFd = -1;
+
+// RSHConn::RSHConn - Constructor /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+RSHConn::RSHConn(std::string const &pProg, URI Srv) : Len(0), WriteFd(-1), ReadFd(-1),
+ ServerName(Srv), Prog(pProg), Process(-1) {
+ Buffer[0] = '\0';
+}
+ /*}}}*/
+// RSHConn::RSHConn - Destructor /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+RSHConn::~RSHConn()
+{
+ Close();
+}
+ /*}}}*/
+// RSHConn::Close - Forcibly terminate the connection /*{{{*/
+// ---------------------------------------------------------------------
+/* Often this is called when things have gone wrong to indicate that the
+ connection is no longer usable. */
+void RSHConn::Close()
+{
+ if (Process == -1)
+ return;
+
+ close(WriteFd);
+ close(ReadFd);
+ kill(Process,SIGINT);
+ ExecWait(Process,"",true);
+ WriteFd = -1;
+ ReadFd = -1;
+ Process = -1;
+}
+ /*}}}*/
+// RSHConn::Open - Connect to a host /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool RSHConn::Open()
+{
+ // Use the already open connection if possible.
+ if (Process != -1)
+ return true;
+
+ if (Connect(ServerName.Host,ServerName.Port,ServerName.User) == false)
+ return false;
+
+ return true;
+}
+ /*}}}*/
+// RSHConn::Connect - Fire up rsh and connect /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool RSHConn::Connect(std::string const &Host, unsigned int Port, std::string const &User)
+{
+ char *PortStr = NULL;
+ if (Port != 0)
+ {
+ if (asprintf (&PortStr, "%d", Port) == -1 || PortStr == NULL)
+ return _error->Errno("asprintf", _("Failed"));
+ }
+
+ // Create the pipes
+ int Pipes[4] = {-1,-1,-1,-1};
+ if (pipe(Pipes) != 0 || pipe(Pipes+2) != 0)
+ {
+ _error->Errno("pipe",_("Failed to create IPC pipe to subprocess"));
+ for (int I = 0; I != 4; I++)
+ close(Pipes[I]);
+ return false;
+ }
+ for (int I = 0; I != 4; I++)
+ SetCloseExec(Pipes[I],true);
+
+ Process = ExecFork();
+
+ // The child
+ if (Process == 0)
+ {
+ const char *Args[400];
+ unsigned int i = 0;
+
+ dup2(Pipes[1],STDOUT_FILENO);
+ dup2(Pipes[2],STDIN_FILENO);
+
+ // Probably should do
+ // dup2(open("/dev/null",O_RDONLY),STDERR_FILENO);
+
+ Args[i++] = Prog.c_str();
+
+ // Insert user-supplied command line options
+ Configuration::Item const *Opts = RshOptions;
+ if (Opts != 0)
+ {
+ Opts = Opts->Child;
+ for (; Opts != 0; Opts = Opts->Next)
+ {
+ if (Opts->Value.empty() == true)
+ continue;
+ Args[i++] = Opts->Value.c_str();
+ }
+ }
+
+ if (User.empty() == false) {
+ Args[i++] = "-l";
+ Args[i++] = User.c_str();
+ }
+ if (PortStr != NULL) {
+ Args[i++] = "-p";
+ Args[i++] = PortStr;
+ }
+ if (Host.empty() == false) {
+ Args[i++] = Host.c_str();
+ }
+ Args[i++] = "/bin/sh";
+ Args[i] = 0;
+ execvp(Args[0],(char **)Args);
+ exit(100);
+ }
+
+ if (PortStr != NULL)
+ free(PortStr);
+
+ ReadFd = Pipes[0];
+ WriteFd = Pipes[3];
+ SetNonBlock(Pipes[0],true);
+ SetNonBlock(Pipes[3],true);
+ close(Pipes[1]);
+ close(Pipes[2]);
+
+ return true;
+}
+bool RSHConn::Connect(std::string const &Host, std::string const &User)
+{
+ return Connect(Host, 0, User);
+}
+ /*}}}*/
+// RSHConn::ReadLine - Very simple buffered read with timeout /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool RSHConn::ReadLine(std::string &Text)
+{
+ if (Process == -1 || ReadFd == -1)
+ return false;
+
+ // 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 = std::string(Buffer,I);
+ memmove(Buffer,Buffer+I,Len - I);
+ Len -= I;
+ return true;
+ }
+
+ // Wait for some data..
+ if (WaitFd(ReadFd,false,TimeOut) == false)
+ {
+ Close();
+ return _error->Error(_("Connection timeout"));
+ }
+
+ // Suck it back
+ int Res = read(ReadFd,Buffer + Len,sizeof(Buffer) - Len);
+ if (Res <= 0)
+ {
+ _error->Errno("read",_("Read error"));
+ Close();
+ return false;
+ }
+ Len += Res;
+ }
+
+ return _error->Error(_("A response overflowed the buffer."));
+}
+ /*}}}*/
+// RSHConn::WriteMsg - Send a message with optional remote sync. /*{{{*/
+// ---------------------------------------------------------------------
+/* The remote sync flag appends a || echo which will insert blank line
+ once the command completes. */
+bool RSHConn::WriteMsg(std::string &Text,bool Sync,const char *Fmt,...)
+{
+ va_list args;
+ va_start(args,Fmt);
+
+ // sprintf into a buffer
+ char Tmp[1024];
+ vsnprintf(Tmp,sizeof(Tmp),Fmt,args);
+ va_end(args);
+
+ // concat to create the real msg
+ std::string Msg;
+ if (Sync == true)
+ Msg = std::string(Tmp) + " 2> /dev/null || echo\n";
+ else
+ Msg = std::string(Tmp) + " 2> /dev/null\n";
+
+ // Send it off
+ const char *S = Msg.c_str();
+ unsigned long Len = strlen(S);
+ unsigned long Start = 0;
+ while (Len != 0)
+ {
+ if (WaitFd(WriteFd,true,TimeOut) == false)
+ {
+
+ Close();
+ return _error->Error(_("Connection timeout"));
+ }
+
+ int Res = write(WriteFd,S + Start,Len);
+ if (Res <= 0)
+ {
+ _error->Errno("write",_("Write error"));
+ Close();
+ return false;
+ }
+
+ Len -= Res;
+ Start += Res;
+ }
+
+ if (Sync == true)
+ return ReadLine(Text);
+ return true;
+}
+ /*}}}*/
+// RSHConn::Size - Return the size of the file /*{{{*/
+// ---------------------------------------------------------------------
+/* Right now for successful transfer the file size must be known in
+ advance. */
+bool RSHConn::Size(const char *Path,unsigned long long &Size)
+{
+ // Query the size
+ std::string Msg;
+ Size = 0;
+
+ if (WriteMsg(Msg,true,"find %s -follow -printf '%%s\\n'",Path) == false)
+ return false;
+
+ // FIXME: Sense if the bad reply is due to a File Not Found.
+
+ char *End;
+ Size = strtoull(Msg.c_str(),&End,10);
+ if (End == Msg.c_str())
+ return _error->Error(_("File not found"));
+ return true;
+}
+ /*}}}*/
+// RSHConn::ModTime - Get the modification time in UTC /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool RSHConn::ModTime(const char *Path, time_t &Time)
+{
+ Time = time(&Time);
+ // Query the mod time
+ std::string Msg;
+
+ if (WriteMsg(Msg,true,"TZ=UTC find %s -follow -printf '%%TY%%Tm%%Td%%TH%%TM%%TS\\n'",Path) == false)
+ return false;
+
+ // Parse it
+ return FTPMDTMStrToTime(Msg.c_str(), Time);
+}
+ /*}}}*/
+// RSHConn::Get - Get a file /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool RSHConn::Get(const char *Path,FileFd &To,unsigned long long Resume,
+ Hashes &Hash,bool &Missing, unsigned long long Size)
+{
+ Missing = false;
+
+ // Round to a 2048 byte block
+ Resume = Resume - (Resume % 2048);
+
+ if (To.Truncate(Resume) == false)
+ return false;
+ if (To.Seek(0) == false)
+ return false;
+
+ if (Resume != 0) {
+ if (Hash.AddFD(To,Resume) == false) {
+ _error->Errno("read",_("Problem hashing file"));
+ return false;
+ }
+ }
+
+ // FIXME: Detect file-not openable type errors.
+ std::string Jnk;
+ if (WriteMsg(Jnk,false,"dd if=%s bs=2048 skip=%u", Path, Resume / 2048) == false)
+ return false;
+
+ // Copy loop
+ unsigned long long MyLen = Resume;
+ unsigned char Buffer[4096];
+ while (MyLen < Size)
+ {
+ // Wait for some data..
+ if (WaitFd(ReadFd,false,TimeOut) == false)
+ {
+ Close();
+ return _error->Error(_("Data socket timed out"));
+ }
+
+ // Read the data..
+ int Res = read(ReadFd,Buffer,sizeof(Buffer));
+ if (Res == 0)
+ {
+ Close();
+ return _error->Error(_("Connection closed prematurely"));
+ }
+
+ if (Res < 0)
+ {
+ if (errno == EAGAIN)
+ continue;
+ break;
+ }
+ MyLen += Res;
+
+ Hash.Add(Buffer,Res);
+ if (To.Write(Buffer,Res) == false)
+ {
+ Close();
+ return false;
+ }
+ }
+
+ return true;
+}
+ /*}}}*/
+
+// RSHMethod::RSHMethod - Constructor /*{{{*/
+RSHMethod::RSHMethod(std::string &&pProg) : aptMethod(std::move(pProg),"1.0",SendConfig | SendURIEncoded)
+{
+ signal(SIGTERM,SigTerm);
+ signal(SIGINT,SigTerm);
+ Server = 0;
+ FailFd = -1;
+}
+ /*}}}*/
+// RSHMethod::Configuration - Handle a configuration message /*{{{*/
+// ---------------------------------------------------------------------
+bool RSHMethod::Configuration(std::string Message)
+{
+ // enabling privilege dropping for this method requires configuration…
+ // … which is otherwise lifted straight from root, so use it by default.
+ _config->Set(std::string("Binary::") + Binary + "::APT::Sandbox::User", "");
+
+ if (aptMethod::Configuration(Message) == false)
+ return false;
+
+ std::string const timeconf = std::string("Acquire::") + Binary + "::Timeout";
+ TimeOut = _config->FindI(timeconf, TimeOut);
+ std::string const optsconf = std::string("Acquire::") + Binary + "::Options";
+ RshOptions = _config->Tree(optsconf.c_str());
+
+ return true;
+}
+ /*}}}*/
+// RSHMethod::SigTerm - Clean up and timestamp the files on exit /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+void RSHMethod::SigTerm(int)
+{
+ if (FailFd == -1)
+ _exit(100);
+
+ // Transfer the modification times
+ 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);
+}
+ /*}}}*/
+// RSHMethod::Fetch - Fetch a URI /*{{{*/
+// ---------------------------------------------------------------------
+/* */
+bool RSHMethod::Fetch(FetchItem *Itm)
+{
+ URI Get(Itm->Uri);
+ auto const File = DecodeSendURI(Get.Path);
+ FetchResult Res;
+ Res.Filename = Itm->DestFile;
+ Res.IMSHit = false;
+
+ // Connect to the server
+ if (Server == 0 || Server->Comp(Get) == false) {
+ delete Server;
+ Server = new RSHConn(Binary, Get);
+ }
+
+ // Could not connect is a transient error..
+ if (Server->Open() == false) {
+ Server->Close();
+ Fail(true);
+ return true;
+ }
+
+ // We say this mainly because the pause here is for the
+ // ssh connection that is still going
+ Status(_("Connecting to %s"), Get.Host.c_str());
+
+ // Get the files information
+ unsigned long long Size;
+ if (not Server->Size(File.c_str(), Size) ||
+ not Server->ModTime(File.c_str(), FailTime))
+ {
+ //Fail(true);
+ //_error->Error(_("File not found")); // Will be handled by Size
+ return false;
+ }
+ Res.Size = Size;
+
+ // See if it is an IMS hit
+ if (Itm->LastModified == FailTime) {
+ Res.Size = 0;
+ Res.IMSHit = true;
+ URIDone(Res);
+ return true;
+ }
+
+ // See if the file exists
+ struct stat Buf;
+ if (stat(Itm->DestFile.c_str(),&Buf) == 0) {
+ if (Size == (unsigned long long)Buf.st_size && FailTime == Buf.st_mtime) {
+ Res.Size = Buf.st_size;
+ Res.LastModified = Buf.st_mtime;
+ Res.ResumePoint = Buf.st_size;
+ URIDone(Res);
+ return true;
+ }
+
+ // Resume?
+ if (FailTime == Buf.st_mtime && Size > (unsigned long long)Buf.st_size)
+ Res.ResumePoint = Buf.st_size;
+ }
+
+ // Open the file
+ Hashes Hash(Itm->ExpectedHashes);
+ {
+ FileFd Fd(Itm->DestFile,FileFd::WriteAny);
+ if (_error->PendingError() == true)
+ return false;
+
+ URIStart(Res);
+
+ FailFile = Itm->DestFile;
+ (void)(FailFile.c_str()); // Make sure we don't do a malloc in the signal handler
+ FailFd = Fd.Fd();
+
+ bool Missing;
+ if (not Server->Get(File.c_str(), Fd, Res.ResumePoint, Hash, Missing, Res.Size))
+ {
+ Fd.Close();
+
+ // Timestamp
+ 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);
+
+ // If the file is missing we hard fail otherwise transient fail
+ if (Missing == true)
+ return false;
+ Fail(true);
+ return true;
+ }
+
+ Res.Size = Fd.Size();
+ struct timeval times[2];
+ times[0].tv_sec = FailTime;
+ times[1].tv_sec = FailTime;
+ times[0].tv_usec = times[1].tv_usec = 0;
+ utimes(Fd.Name().c_str(), times);
+ FailFd = -1;
+ }
+
+ Res.LastModified = FailTime;
+ Res.TakeHashes(Hash);
+
+ URIDone(Res);
+
+ return true;
+}
+ /*}}}*/
+
+int main(int, const char *argv[])
+{
+ return RSHMethod(flNotDir(argv[0])).Run();
+}
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