methods/rsh.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: rsh.cc,v 1.7 2004/01/07 20:39:38 mdz Exp $
   4 /* ######################################################################
   5
   6    RSH method - Transfer files via rsh compatible program
   7
   8    Written by Ben Collins <bcollins@debian.org>, Copyright (c) 2000
   9    Licensed under the GNU General Public License v2 [no exception clauses]
  10
  11    ##################################################################### */
  12                                                                         /*}}}*/
  13 // Include Files                                                        /*{{{*/
  14 #include "rsh.h"
  15 #include <apt-pkg/error.h>
  16
  17 #include <sys/stat.h>
  18 #include <sys/time.h>
  19 #include <utime.h>
  20 #include <unistd.h>
  21 #include <signal.h>
  22 #include <stdio.h>
  23 #include <errno.h>
  24 #include <stdarg.h>
  25 #include <apti18n.h>
  26                                                                         /*}}}*/
  27
  28 const char *Prog;
  29 unsigned long TimeOut = 120;
  30 Configuration::Item const *RshOptions = 0;
  31 time_t RSHMethod::FailTime = 0;
  32 string RSHMethod::FailFile;
  33 int RSHMethod::FailFd = -1;
  34
  35 // RSHConn::RSHConn - Constructor                                       /*{{{*/
  36 // ---------------------------------------------------------------------
  37 /* */
  38 RSHConn::RSHConn(URI Srv) : Len(0), WriteFd(-1), ReadFd(-1),
  39                             ServerName(Srv), Process(-1) {}
  40                                                                         /*}}}*/
  41 // RSHConn::RSHConn - Destructor                                        /*{{{*/
  42 // ---------------------------------------------------------------------
  43 /* */
  44 RSHConn::~RSHConn()
  45 {
  46    Close();
  47 }
  48                                                                         /*}}}*/
  49 // RSHConn::Close - Forcibly terminate the connection                   /*{{{*/
  50 // ---------------------------------------------------------------------
  51 /* Often this is called when things have gone wrong to indicate that the
  52    connection is no longer usable. */
  53 void RSHConn::Close()
  54 {
  55    if (Process == -1)
  56       return;
  57
  58    close(WriteFd);
  59    close(ReadFd);
  60    kill(Process,SIGINT);
  61    ExecWait(Process,"",true);
  62    WriteFd = -1;
  63    ReadFd = -1;
  64    Process = -1;
  65 }
  66                                                                         /*}}}*/
  67 // RSHConn::Open - Connect to a host                                    /*{{{*/
  68 // ---------------------------------------------------------------------
  69 /* */
  70 bool RSHConn::Open()
  71 {
  72    // Use the already open connection if possible.
  73    if (Process != -1)
  74       return true;
  75
  76    if (Connect(ServerName.Host,ServerName.User) == false)
  77       return false;
  78
  79    return true;
  80 }
  81                                                                         /*}}}*/
  82 // RSHConn::Connect - Fire up rsh and connect                           /*{{{*/
  83 // ---------------------------------------------------------------------
  84 /* */
  85 bool RSHConn::Connect(string Host, string User)
  86 {
  87    // Create the pipes
  88    int Pipes[4] = {-1,-1,-1,-1};
  89    if (pipe(Pipes) != 0 || pipe(Pipes+2) != 0)
  90    {
  91       _error->Errno("pipe",_("Failed to create IPC pipe to subprocess"));
  92       for (int I = 0; I != 4; I++)
  93          close(Pipes[I]);
  94       return false;
  95    }
  96    for (int I = 0; I != 4; I++)
  97       SetCloseExec(Pipes[I],true);
  98
  99    Process = ExecFork();
 100
 101    // The child
 102    if (Process == 0)
 103    {
 104       const char *Args[400];
 105       unsigned int i = 0;
 106
 107       dup2(Pipes[1],STDOUT_FILENO);
 108       dup2(Pipes[2],STDIN_FILENO);
 109
 110       // Probably should do
 111       // dup2(open("/dev/null",O_RDONLY),STDERR_FILENO);
 112
 113       // Insert user-supplied command line options
 114       Configuration::Item const *Opts = RshOptions;
 115       if (Opts != 0)
 116       {
 117          Opts = Opts->Child;
 118          for (; Opts != 0; Opts = Opts->Next)
 119          {
 120             if (Opts->Value.empty() == true)
 121                continue;
 122             Args[i++] = Opts->Value.c_str();
 123          }
 124       }
 125
 126       Args[i++] = Prog;
 127       if (User.empty() == false) {
 128          Args[i++] = "-l";
 129          Args[i++] = User.c_str();
 130       }
 131       if (Host.empty() == false) {
 132          Args[i++] = Host.c_str();
 133       }
 134       Args[i++] = "/bin/sh";
 135       Args[i] = 0;
 136       execvp(Args[0],(char **)Args);
 137       exit(100);
 138    }
 139
 140    ReadFd = Pipes[0];
 141    WriteFd = Pipes[3];
 142    SetNonBlock(Pipes[0],true);
 143    SetNonBlock(Pipes[3],true);
 144    close(Pipes[1]);
 145    close(Pipes[2]);
 146
 147    return true;
 148 }
 149                                                                         /*}}}*/
 150 // RSHConn::ReadLine - Very simple buffered read with timeout           /*{{{*/
 151 // ---------------------------------------------------------------------
 152 /* */
 153 bool RSHConn::ReadLine(string &Text)
 154 {
 155    if (Process == -1 || ReadFd == -1)
 156       return false;
 157
 158    // Suck in a line
 159    while (Len < sizeof(Buffer))
 160    {
 161       // Scan the buffer for a new line
 162       for (unsigned int I = 0; I != Len; I++)
 163       {
 164          // Escape some special chars
 165          if (Buffer[I] == 0)
 166             Buffer[I] = '?';
 167
 168          // End of line?
 169          if (Buffer[I] != '\n')
 170             continue;
 171
 172          I++;
 173          Text = string(Buffer,I);
 174          memmove(Buffer,Buffer+I,Len - I);
 175          Len -= I;
 176          return true;
 177       }
 178
 179       // Wait for some data..
 180       if (WaitFd(ReadFd,false,TimeOut) == false)
 181       {
 182          Close();
 183          return _error->Error(_("Connection timeout"));
 184       }
 185
 186       // Suck it back
 187       int Res = read(ReadFd,Buffer + Len,sizeof(Buffer) - Len);
 188       if (Res <= 0)
 189       {
 190          _error->Errno("read",_("Read error"));
 191          Close();
 192          return false;
 193       }
 194       Len += Res;
 195    }
 196
 197    return _error->Error(_("A response overflowed the buffer."));
 198 }
 199                                                                         /*}}}*/
 200 // RSHConn::WriteMsg - Send a message with optional remote sync.        /*{{{*/
 201 // ---------------------------------------------------------------------
 202 /* The remote sync flag appends a || echo which will insert blank line
 203    once the command completes. */
 204 bool RSHConn::WriteMsg(string &Text,bool Sync,const char *Fmt,...)
 205 {
 206    va_list args;
 207    va_start(args,Fmt);
 208
 209    // sprintf the description
 210    char S[512];
 211    vsnprintf(S,sizeof(S) - 4,Fmt,args);
 212    if (Sync == true)
 213       strcat(S," 2> /dev/null || echo\n");
 214    else
 215       strcat(S," 2> /dev/null\n");
 216
 217    // Send it off
 218    unsigned long Len = strlen(S);
 219    unsigned long Start = 0;
 220    while (Len != 0)
 221    {
 222       if (WaitFd(WriteFd,true,TimeOut) == false)
 223       {
 224
 225          Close();
 226          return _error->Error(_("Connection timeout"));
 227       }
 228
 229       int Res = write(WriteFd,S + Start,Len);
 230       if (Res <= 0)
 231       {
 232          _error->Errno("write",_("Write Error"));
 233          Close();
 234          return false;
 235       }
 236
 237       Len -= Res;
 238       Start += Res;
 239    }
 240
 241    if (Sync == true)
 242       return ReadLine(Text);
 243    return true;
 244 }
 245                                                                         /*}}}*/
 246 // RSHConn::Size - Return the size of the file                          /*{{{*/
 247 // ---------------------------------------------------------------------
 248 /* Right now for successfull transfer the file size must be known in
 249    advance. */
 250 bool RSHConn::Size(const char *Path,unsigned long &Size)
 251 {
 252    // Query the size
 253    string Msg;
 254    Size = 0;
 255
 256    if (WriteMsg(Msg,true,"find %s -follow -printf '%%s\\n'",Path) == false)
 257       return false;
 258
 259    // FIXME: Sense if the bad reply is due to a File Not Found.
 260
 261    char *End;
 262    Size = strtoul(Msg.c_str(),&End,10);
 263    if (End == Msg.c_str())
 264       return _error->Error(_("File Not Found"));
 265    return true;
 266 }
 267                                                                         /*}}}*/
 268 // RSHConn::ModTime - Get the modification time in UTC                  /*{{{*/
 269 // ---------------------------------------------------------------------
 270 /* */
 271 bool RSHConn::ModTime(const char *Path, time_t &Time)
 272 {
 273    Time = time(&Time);
 274    // Query the mod time
 275    string Msg;
 276
 277    if (WriteMsg(Msg,true,"TZ=UTC find %s -follow -printf '%%TY%%Tm%%Td%%TH%%TM%%TS\\n'",Path) == false)
 278       return false;
 279
 280    // Parse it
 281    StrToTime(Msg,Time);
 282    return true;
 283 }
 284                                                                         /*}}}*/
 285 // RSHConn::Get - Get a file                                            /*{{{*/
 286 // ---------------------------------------------------------------------
 287 /* */
 288 bool RSHConn::Get(const char *Path,FileFd &To,unsigned long Resume,
 289                   Hashes &Hash,bool &Missing, unsigned long Size)
 290 {
 291    Missing = false;
 292
 293    // Round to a 2048 byte block
 294    Resume = Resume - (Resume % 2048);
 295
 296    if (To.Truncate(Resume) == false)
 297       return false;
 298    if (To.Seek(0) == false)
 299       return false;
 300
 301    if (Resume != 0) {
 302       if (Hash.AddFD(To.Fd(),Resume) == false) {
 303          _error->Errno("read",_("Problem hashing file"));
 304          return false;
 305       }
 306    }
 307
 308    // FIXME: Detect file-not openable type errors.
 309    string Jnk;
 310    if (WriteMsg(Jnk,false,"dd if=%s bs=2048 skip=%u", Path, Resume / 2048) == false)
 311       return false;
 312
 313    // Copy loop
 314    unsigned int MyLen = Resume;
 315    unsigned char Buffer[4096];
 316    while (MyLen < Size)
 317    {
 318       // Wait for some data..
 319       if (WaitFd(ReadFd,false,TimeOut) == false)
 320       {
 321          Close();
 322          return _error->Error(_("Data socket timed out"));
 323       }
 324
 325       // Read the data..
 326       int Res = read(ReadFd,Buffer,sizeof(Buffer));
 327       if (Res == 0)
 328       {
 329          Close();
 330          return _error->Error(_("Connection closed prematurely"));
 331       }
 332
 333       if (Res < 0)
 334       {
 335          if (errno == EAGAIN)
 336             continue;
 337          break;
 338       }
 339       MyLen += Res;
 340
 341       Hash.Add(Buffer,Res);
 342       if (To.Write(Buffer,Res) == false)
 343       {
 344          Close();
 345          return false;
 346       }
 347    }
 348
 349    return true;
 350 }
 351                                                                         /*}}}*/
 352
 353 // RSHMethod::RSHMethod - Constructor                                   /*{{{*/
 354 // ---------------------------------------------------------------------
 355 /* */
 356 RSHMethod::RSHMethod() : pkgAcqMethod("1.0",SendConfig)
 357 {
 358    signal(SIGTERM,SigTerm);
 359    signal(SIGINT,SigTerm);
 360    Server = 0;
 361    FailFd = -1;
 362 };
 363                                                                         /*}}}*/
 364 // RSHMethod::Configuration - Handle a configuration message            /*{{{*/
 365 // ---------------------------------------------------------------------
 366 bool RSHMethod::Configuration(string Message)
 367 {
 368    char ProgStr[100];
 369
 370    if (pkgAcqMethod::Configuration(Message) == false)
 371       return false;
 372
 373    snprintf(ProgStr, sizeof ProgStr, "Acquire::%s::Timeout", Prog);
 374    TimeOut = _config->FindI(ProgStr,TimeOut);
 375    snprintf(ProgStr, sizeof ProgStr, "Acquire::%s::Options", Prog);
 376    RshOptions = _config->Tree(ProgStr);
 377
 378    return true;
 379 }
 380                                                                         /*}}}*/
 381 // RSHMethod::SigTerm - Clean up and timestamp the files on exit        /*{{{*/
 382 // ---------------------------------------------------------------------
 383 /* */
 384 void RSHMethod::SigTerm(int sig)
 385 {
 386    if (FailFd == -1)
 387       _exit(100);
 388    close(FailFd);
 389
 390    // Timestamp
 391    struct utimbuf UBuf;
 392    UBuf.actime = FailTime;
 393    UBuf.modtime = FailTime;
 394    utime(FailFile.c_str(),&UBuf);
 395
 396    _exit(100);
 397 }
 398                                                                         /*}}}*/
 399 // RSHMethod::Fetch - Fetch a URI                                       /*{{{*/
 400 // ---------------------------------------------------------------------
 401 /* */
 402 bool RSHMethod::Fetch(FetchItem *Itm)
 403 {
 404    URI Get = Itm->Uri;
 405    const char *File = Get.Path.c_str();
 406    FetchResult Res;
 407    Res.Filename = Itm->DestFile;
 408    Res.IMSHit = false;
 409
 410    // Connect to the server
 411    if (Server == 0 || Server->Comp(Get) == false) {
 412       delete Server;
 413       Server = new RSHConn(Get);
 414    }
 415
 416    // Could not connect is a transient error..
 417    if (Server->Open() == false) {
 418       Server->Close();
 419       Fail(true);
 420       return true;
 421    }
 422
 423    // We say this mainly because the pause here is for the
 424    // ssh connection that is still going
 425    Status(_("Connecting to %s"), Get.Host.c_str());
 426
 427    // Get the files information
 428    unsigned long Size;
 429    if (Server->Size(File,Size) == false ||
 430        Server->ModTime(File,FailTime) == false)
 431    {
 432       //Fail(true);
 433       //_error->Error(_("File Not Found")); // Will be handled by Size
 434       return false;
 435    }
 436    Res.Size = Size;
 437
 438    // See if it is an IMS hit
 439    if (Itm->LastModified == FailTime) {
 440       Res.Size = 0;
 441       Res.IMSHit = true;
 442       URIDone(Res);
 443       return true;
 444    }
 445
 446    // See if the file exists
 447    struct stat Buf;
 448    if (stat(Itm->DestFile.c_str(),&Buf) == 0) {
 449       if (Size == (unsigned)Buf.st_size && FailTime == Buf.st_mtime) {
 450          Res.Size = Buf.st_size;
 451          Res.LastModified = Buf.st_mtime;
 452          Res.ResumePoint = Buf.st_size;
 453          URIDone(Res);
 454          return true;
 455       }
 456
 457       // Resume?
 458       if (FailTime == Buf.st_mtime && Size > (unsigned)Buf.st_size)
 459          Res.ResumePoint = Buf.st_size;
 460    }
 461
 462    // Open the file
 463    Hashes Hash;
 464    {
 465       FileFd Fd(Itm->DestFile,FileFd::WriteAny);
 466       if (_error->PendingError() == true)
 467          return false;
 468
 469       URIStart(Res);
 470
 471       FailFile = Itm->DestFile;
 472       FailFile.c_str();   // Make sure we dont do a malloc in the signal handler
 473       FailFd = Fd.Fd();
 474
 475       bool Missing;
 476       if (Server->Get(File,Fd,Res.ResumePoint,Hash,Missing,Res.Size) == false)
 477       {
 478          Fd.Close();
 479
 480          // Timestamp
 481          struct utimbuf UBuf;
 482          UBuf.actime = FailTime;
 483          UBuf.modtime = FailTime;
 484          utime(FailFile.c_str(),&UBuf);
 485
 486          // If the file is missing we hard fail otherwise transient fail
 487          if (Missing == true)
 488             return false;
 489          Fail(true);
 490          return true;
 491       }
 492
 493       Res.Size = Fd.Size();
 494    }
 495
 496    Res.LastModified = FailTime;
 497    Res.TakeHashes(Hash);
 498
 499    // Timestamp
 500    struct utimbuf UBuf;
 501    UBuf.actime = FailTime;
 502    UBuf.modtime = FailTime;
 503    utime(Queue->DestFile.c_str(),&UBuf);
 504    FailFd = -1;
 505
 506    URIDone(Res);
 507
 508    return true;
 509 }
 510                                                                         /*}}}*/
 511
 512 int main(int argc, const char *argv[])
 513 {
 514    setlocale(LC_ALL, "");
 515
 516    RSHMethod Mth;
 517    Prog = strrchr(argv[0],'/');
 518    Prog++;
 519    return Mth.Run();
 520 }