mdw@git.distorted.org.uk Git - sw-tools/blob - src/sw_rsh.c

   1 /* -*-c-*-
   2  *
   3  * $Id: sw_rsh.c,v 1.7 1999/09/24 13:16:22 mdw Exp $
   4  *
   5  * Run remote commands
   6  *
   7  * (c) 1999 EBI
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of sw-tools.
  13  *
  14  * sw-tools is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * sw-tools is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with sw-tools; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: sw_rsh.c,v $
  32  * Revision 1.7  1999/09/24 13:16:22  mdw
  33  * Fix typo in comment.
  34  *
  35  * Revision 1.6  1999/09/24 13:15:57  mdw
  36  * Remove unnecessary assumptions about structure layouts.  (The `pkhead'
  37  * structure is no more.)
  38  *
  39  * Revision 1.5  1999/06/24 16:02:22  mdw
  40  * Fix signal handling some more.
  41  *
  42  * Revision 1.4  1999/06/24 15:51:17  mdw
  43  * Fix signal handlers so they don't corrupt `errno'.
  44  *
  45  * Revision 1.3  1999/06/18 18:58:54  mdw
  46  * Signal handling fixes.
  47  *
  48  * Revision 1.2  1999/06/02 17:03:29  mdw
  49  * Fix use of `octet' now that mLib includes `bits.h' (as of version 1.3.5
  50  * release).  Also use the mLib load and store macros rather than doing it
  51  * by hand.
  52  *
  53  * Revision 1.1.1.1  1999/06/02  16:53:34  mdw
  54  * Initial import.
  55  *
  56  */
  57
  58 /*----- Header files ------------------------------------------------------*/
  59
  60 #include "config.h"
  61
  62 #include <ctype.h>
  63 #include <errno.h>
  64 #include <signal.h>
  65 #include <stdarg.h>
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <string.h>
  69
  70 #include <sys/types.h>
  71 #include <sys/time.h>
  72 #include <fcntl.h>
  73 #include <unistd.h>
  74
  75 #include <sys/socket.h>
  76 #include <sys/wait.h>
  77
  78 #ifndef DECL_ENVIRON
  79   extern char **environ;
  80 #endif
  81
  82 #include <mLib/alloc.h>
  83 #include <mLib/bits.h>
  84 #include <mLib/dstr.h>
  85 #include <mLib/exc.h>
  86 #include <mLib/mdwopt.h>
  87 #include <mLib/quis.h>
  88 #include <mLib/report.h>
  89 #include <mLib/sym.h>
  90
  91 #define RCMD_LINK 0
  92 #include "sw_arch.h"
  93 #include "sw_build.h"
  94 #include "sw_env.h"
  95 #include "sw_rsh.h"
  96
  97 /*----- Data structures ---------------------------------------------------*/
  98
  99 #define PKHEADSZ 3
 100
 101 /*----- Static variables --------------------------------------------------*/
 102
 103 static int handler = 0;
 104 static rcmd *rcmds = RCMD_LINK;
 105
 106 /*----- Packet interface --------------------------------------------------*/
 107
 108 /* --- @pksend@ --- *
 109  *
 110  * Arguments:   @sw_remote@ = pointer to the remote block
 111  *              @int type@ = packet type to send
 112  *              @const void *p@ = pointer to packet data
 113  *              @size_t sz@ = size of data to send
 114  *
 115  * Returns:     Zero if it worked, nonzero otherwise.
 116  *
 117  * Use:         Sends a data packet.  If the type is `data', then `sz' may be
 118  *              arbitrarily large and is divided into small enough chunks.
 119  *              Otherwise it's an error to send a packet that's too big.
 120  */
 121
 122 int pksend(sw_remote *r, int type, const void *p, size_t sz)
 123 {
 124   octet h[PKHEADSZ];
 125   const char *q = p;
 126   size_t chunk;
 127
 128   /* --- Sort out error conditions --- */
 129
 130   if (sz > PKMAX && type != PKTYPE_DATA) {
 131     errno = E2BIG;
 132     return (-1);
 133   }
 134
 135   /* --- Main output loop --- */
 136
 137   h[2] = type;
 138   do {
 139
 140     /* --- Set up the packet header --- */
 141
 142     chunk = (sz > PKMAX ? PKMAX : sz);
 143     STORE16(h, chunk);
 144
 145     /* --- Write the packet header --- */
 146
 147   try_again:
 148     if (write(r->fdout, &h, PKHEADSZ) < PKHEADSZ) {
 149       if (errno == EINTR)
 150         goto try_again;
 151       return (-1);
 152     }
 153
 154     /* --- Write the payload, if there is one --- *
 155      *
 156      * Maybe the OS won't want to bite it all off in one go.
 157      */
 158
 159     while (chunk) {
 160       ssize_t n = write(r->fdout, q, chunk);
 161       if (n < 0 && errno != EINTR)
 162         return (-1);
 163       if (n > 0) {
 164         q += n;
 165         chunk -= n;
 166         sz -= n;
 167       }
 168     }
 169   } while (sz);
 170
 171   /* --- Done --- */
 172
 173   return (0);
 174 }
 175
 176 /* --- @pkrecv@ --- *
 177  *
 178  * Arguments:   @sw_remote *r@ = remote block
 179  *
 180  * Returns:     Packet type received, or @-1@ for an error.
 181  *
 182  * Use:         Receives a packet from the remote host.  The packet data is
 183  *              placed in the block's buffer, the block's packet length is
 184  *              diddled appropriately.
 185  */
 186
 187 int pkrecv(sw_remote *r)
 188 {
 189   octet h[PKHEADSZ];
 190   size_t sz;
 191   char *p;
 192   ssize_t n;
 193
 194   /* --- Read the packet header --- */
 195
 196   sz = PKHEADSZ;
 197   p = (char *)&h;
 198   while (sz) {
 199     n = read(r->fdin, p, sz);
 200     if (n < 0 && errno != EINTR)
 201       return (-1);
 202     if (n == 0)
 203       return (PKTYPE_EOF);
 204     if (n > 0) {
 205       p += n;
 206       sz -= n;
 207     }
 208   }
 209
 210   /* --- Hack for error messages --- *
 211    *
 212    * If it doesn't look like a valid packet, read a `chunk' and pretend it's
 213    * data.  This isn't too bad, because all the packet types are control
 214    * codes, and are unlikely to be in a textual message.
 215    *
 216    * Normally what happens here is that something sitting before the `sw'
 217    * program fails, reports a plain textual error, and exits.  Grabbing the
 218    * `last gasp' like this, then, traps that error message and allows
 219    * something to report it.  The rest ought to be completely silent, so I
 220    * get an `unexpected eof' and then drop everything.
 221    *
 222    * This is certainly better than the behaviour otherwise, which is an
 223    * @E2BIG@ message reported when the packet size is really ASCII
 224    * characters.
 225    */
 226
 227   if (h[2] >= PKTYPE_BOGUS) {
 228     memcpy(r->buf, &h, PKHEADSZ);
 229     n = read(r->fdin, r->buf + PKHEADSZ, sizeof(r->buf) - PKHEADSZ);
 230     if (n < 0)
 231       return (-1);
 232     r->sz = n + PKHEADSZ;
 233     return (PKTYPE_DATA);
 234   }
 235
 236   /* --- Sort out what's going on --- */
 237
 238   sz = LOAD16(h);
 239   r->sz = sz;
 240   if (!sz)
 241     return (h[2]);
 242   if (sz > PKMAX) {
 243     errno = E2BIG;
 244     return (-1);
 245   }
 246
 247   /* --- Read the packet payload --- */
 248
 249   p = r->buf;
 250   while (sz) {
 251     n = read(r->fdin, p, sz);
 252     if (n < 0 && errno != EINTR)
 253       return (-1);
 254     if (n == 0)
 255       return (PKTYPE_EOF);
 256     if (n > 0) {
 257       p += n;
 258       sz -= n;
 259     }
 260   }
 261
 262   return (h[2]);
 263 }
 264
 265 /*----- Error reporting and exit statuses --------------------------------*/
 266
 267 /* --- @swexit@ --- *
 268  *
 269  * Arguments:   @sw_remote *r@ = remote context
 270  *              @int status@ = exit status to return
 271  *
 272  * Returns:     Doesn't.
 273  *
 274  * Use:         Reports the exit status via packet protocol and quits.
 275  */
 276
 277 void swexit(sw_remote *r, int status)
 278 {
 279   unsigned char s = status;
 280   pksend(r, PKTYPE_STATUS, &s, 1);
 281   _exit(status);
 282 }
 283
 284 /* --- @swsignal@ --- *
 285  *
 286  * Arguments:   @sw_remote *r@ = remote context
 287  *              @int sig@ = signal ocurrence to return
 288  *
 289  * Returns:     Doesn't.
 290  *
 291  * Use:         Reports a signalled-to-death status via packet protocol and
 292  *              quits.
 293  */
 294
 295 void swsignal(sw_remote *r, int sig)
 296 {
 297 #if defined(HAVE_STRSIGNAL)
 298   char *s = strsignal(sig);
 299 #elif defined(HAVE__SYS_SIGLIST)
 300   char *s = _sys_siglist[sig];
 301 #else
 302   char s[16];
 303   sprintf(s, "signal %i", sig);
 304 #endif
 305
 306   pksend(r, PKTYPE_STATUS, s, strlen(s) + 1);
 307   _exit(127);
 308 }
 309
 310 /* --- @swwait@ --- *
 311  *
 312  * Arguments:   @sw_remote *r@ = remote context
 313  *              @int status@ = status answer from @wait@(2)
 314  *
 315  * Returns:     Doesn't.
 316  *
 317  * Use:         Reports a child's demise appropriately, and quits.
 318  */
 319
 320 void swwait(sw_remote *r, int status)
 321 {
 322   if (WIFEXITED(status))
 323     swexit(r, WEXITSTATUS(status));
 324   else if (WIFSIGNALED(status))
 325     swsignal(r, WTERMSIG(status));
 326   else
 327     swexit(r, 126);
 328 }
 329
 330 /* --- @swvprintf@ --- *
 331  *
 332  * Arguments:   @sw_remote *r@ = remote context
 333  *              @const char *format@ = format string
 334  *              @va_list ap@ = things to format
 335  *
 336  * Returns:     ---
 337  *
 338  * Use:         Writes a string to the remote end.  This is the low-level bit
 339  *              of @swprintf@.
 340  */
 341
 342 void swvprintf(sw_remote *r, const char *format, va_list ap)
 343 {
 344   dstr d = DSTR_INIT;
 345   dstr_vputf(&d, format, ap);
 346   pksend(r, PKTYPE_DATA, d.buf, d.len);
 347   dstr_destroy(&d);
 348 }
 349
 350 /* --- @swprintf@ --- *
 351  *
 352  * Arguments:   @sw_remote *r@ = remote context
 353  *              @const char *format@ = format string
 354  *              @...@ = other arguments
 355  *
 356  * Returns:     ---
 357  *
 358  * Use:         Writes a string to the remote end.
 359  */
 360
 361 void swprintf(sw_remote *r, const char *format, ...)
 362 {
 363   va_list ap;
 364   va_start(ap, format);
 365   swvprintf(r, format, ap);
 366   va_end(ap);
 367 }
 368
 369 /* --- @swdie@ --- *
 370  *
 371  * Arguments:   @sw_remote *r@ = remote context
 372  *              @int status@ = exit status to report
 373  *              @const char *format@ = format string to fill in
 374  *              @...@ = other arguments
 375  *
 376  * Returns:     Doesn't.
 377  *
 378  * Use:         Reports a message and quits.
 379  */
 380
 381 void swdie(sw_remote *r, int status, const char *format, ...)
 382 {
 383   va_list ap;
 384   dstr d = DSTR_INIT;
 385
 386   va_start(ap, format);
 387   dstr_putf(&d, "%s [remote]: ", QUIS);
 388   dstr_vputf(&d, format, ap);
 389   dstr_putc(&d, '\n');
 390   dstr_putz(&d);
 391   va_end(ap);
 392   pksend(r, PKTYPE_DATA, d.buf, d.len);
 393   dstr_destroy(&d);
 394   swexit(r, status);
 395 }
 396
 397 /*----- Command handling and dispatch -------------------------------------*/
 398
 399 /* --- @remote@ --- *
 400  *
 401  * Arguments:   @sw_remote *r@ = pointer to remote block
 402  *              @const char *cmd@ = command to run
 403  *              @char *argv[]@ = argument array
 404  *              @char *env[]@ = environment variables
 405  *
 406  * Returns:     Doesn't.  Reports an exit status through packet protocol and
 407  *              quits.
 408  *
 409  * Use:         Dispatches a remote command.  At this point, the two code
 410  *              paths for local and remote invokation have joined again.
 411  */
 412
 413 static void remote(sw_remote *r, const char *cmd, char *argv[], char *env[])
 414 {
 415   struct rcmd *p, *chosen = 0;
 416   size_t sz = strlen(cmd);
 417
 418   /* --- Make sure that I can get the exit status of children --- */
 419
 420   signal(SIGCHLD, SIG_DFL);
 421
 422   /* --- Fix up the environment --- */
 423
 424   {
 425     sym_table t;
 426     sym_create(&t);
 427     env_import(&t, env);
 428     if (env != environ) {
 429       free(env);
 430       env_import(&t, environ);
 431     }
 432     env_put(&t, "SW_ARCH", ARCH);
 433     env_file(&t, DATADIR "/sw-env");
 434     env = env_export(&t);
 435   }
 436
 437   /* --- Dispatch to the command handler --- */
 438
 439   for (p = rcmds; p; p = p->next) {
 440     if (strncmp(cmd, p->name, sz) == 0) {
 441       if (p->name[sz] == 0) {
 442         chosen = p;
 443         break;
 444       } else if (chosen)
 445         swdie(r, 1, "ambiguous remote command name `%s'", cmd);
 446       else
 447         chosen = p;
 448     }
 449   }
 450   if (!chosen)
 451     swdie(r, 1, "unknown remote command name `%s'", cmd);
 452   chosen->rcmd(r, argv, env);
 453 }
 454
 455 /*----- Remote invocation -------------------------------------------------*/
 456
 457 /* --- @sendargv@ --- *
 458  *
 459  * Arguments:   @sw_remote *r@ = pointer to the remote context
 460  *              @int type@ = packet type to send with
 461  *              @char *v[]@ = pointer to the array to send
 462  *
 463  * Returns:     Zero if OK, nonzero if it failed.
 464  *
 465  * Use:         Sends something @argv@-shaped; i.e., an array of strings
 466  *              terminated by a null pointer.
 467  */
 468
 469 static int sendargv(sw_remote *r, int type, char *v[])
 470 {
 471   dstr d = DSTR_INIT;
 472   int e;
 473
 474   while (*v) {
 475     dstr_puts(&d, *v);
 476     d.len++;                            /* Make the null `real' */
 477     v++;
 478   }
 479   e = pksend(r, type, d.buf, d.len);
 480   dstr_destroy(&d);
 481   return (e);
 482 }
 483
 484 /* --- @snarfargv@ --- *
 485  *
 486  * Arguments:   @const char *buf@ = pointer to buffer
 487  *              @size_t sz@ = size of buffer
 488  *
 489  * Returns:     Pointer to argument array (allocated with @malloc@).
 490  *
 491  * Use:         Snarfs the null-terminated strings in the buffer and returns
 492  *              an array of them.  The whole lot, strings and array, is
 493  *              returned in one big chunk allocated from the heap.  Note that
 494  *              this means it's OK to throw the initial buffer away.
 495  */
 496
 497 static char **snarfargv(const char *buf, size_t sz)
 498 {
 499   /* --- Initial setup --- */
 500
 501   const char *p, *lim;
 502   char *q;
 503   size_t c;
 504   char **v, **w;
 505
 506   /* --- Pass one: count the number of arguments --- */
 507
 508   c = 0;
 509   p = buf;
 510   lim = p + sz;
 511   while (p < lim) {
 512     c++;
 513     while (*p) {
 514       p++;
 515       if (p >= lim)
 516         goto done_pass1;
 517     }
 518     p++;
 519   }
 520 done_pass1:
 521
 522   /* --- Allocate memory for everything --- */
 523
 524   v = xmalloc((c + 1) * sizeof(char *) + sz + 1);
 525   q = (char *)(v + c + 1);
 526   memcpy(q, buf, sz);
 527
 528   /* --- Pass two: set up the arrays --- */
 529
 530   lim = q + sz;
 531   w = v;
 532   while (q < lim) {
 533     *w++ = q;
 534     while (*q) {
 535       q++;
 536       if (q >= lim)
 537         goto done_pass2;
 538     }
 539     q++;
 540   }
 541 done_pass2:
 542   *w++ = 0;
 543   *q++ = 0;
 544
 545   /* --- Done --- */
 546
 547   return (v);
 548 }
 549
 550 /* --- @swrsh_remote@ --- *
 551  *
 552  * Arguments:   @const char *cmd@ = the command to perform
 553  *
 554  * Returns:     Doesn't.  Reports an exit status through packet protocol and
 555  *              quits.
 556  *
 557  * Use:         Handles the remote end of a remote job invokation.
 558  */
 559
 560 void swrsh_remote(const char *cmd)
 561 {
 562   sw_remote r;
 563   static char *dummy = 0;
 564   char **argv = 0;
 565   char **env = 0;
 566   char *dir = 0;
 567   r.fdin = 0;
 568   r.fdout = 1;
 569
 570  /* --- Read packets from the remote host --- */
 571
 572   for (;;) {
 573     int t = pkrecv(&r);
 574     switch (t) {
 575       case -1:
 576         swdie(&r, 1, "error reading packet: %s", strerror(errno));
 577         break;
 578       case PKTYPE_EOF:
 579         goto done;
 580       case PKTYPE_ARGS:
 581         if (argv)
 582           free(argv);
 583         argv = snarfargv(r.buf, r.sz);
 584         break;
 585       case PKTYPE_ENV:
 586         if (env)
 587           free(env);
 588         env = snarfargv(r.buf, r.sz);
 589         break;
 590       case PKTYPE_DIR:
 591         if (dir)
 592           free(dir);
 593         r.buf[r.sz] = 0;
 594         dir = xstrdup(r.buf);
 595         break;
 596       case PKTYPE_GO:
 597         goto done;
 598       case PKTYPE_DATA:
 599       case PKTYPE_STATUS:
 600         swdie(&r, 1, "internal error: unexpected packet");
 601         break;
 602     }
 603   }
 604
 605   /* --- Sort out any missing arguments --- */
 606
 607 done:
 608   if (!argv)
 609     argv = &dummy;
 610   if (!env)
 611     env = &dummy;
 612   if (dir)
 613     chdir(dir);
 614
 615   /* --- Run the command --- */
 616
 617   TRY
 618     remote(&r, cmd, argv, env);
 619   CATCH switch (exc_type) {
 620     case EXC_NOMEM: {
 621       static char msg[] = "\nsw [remote]: not enough memory\n";
 622       pksend(&r, PKTYPE_DATA, msg, sizeof(msg) - 1);
 623       swexit(&r, 1);
 624     } break;
 625     default:
 626       swdie(&r, 1, "uncaught exception, type = %lx", exc_type);
 627   } END_TRY;
 628 }
 629
 630 /*----- Starting remote jobs ----------------------------------------------*/
 631
 632 /* --- @sigchld@ --- *
 633  *
 634  * Arguments:   @int sig@ = the signal number
 635  *
 636  * Returns:     ---
 637  *
 638  * Use:         Catches @SIGCHLD@ and reaps any children that have lost.
 639  */
 640
 641 static void sigchld(int sig)
 642 {
 643   int e = errno;
 644 #ifdef DEBUG_SIGCHLD
 645   int status;
 646   while (waitpid(-1, &status, WNOHANG) > 0) {
 647     if (WIFEXITED(status)) {
 648       fprintf(stderr, "reap child with exit status %i\n",
 649               WEXITSTATUS(status));
 650     } else if (WIFSIGNALED(status)) {
 651       fprintf(stderr, "reap child killed by signal %s\n",
 652               strsignal(WTERMSIG(status)));
 653     } else
 654       fprintf(stderr, "reaped bizarre child which is still alive\n");
 655   }
 656 #else
 657   while (waitpid(-1, 0, WNOHANG) > 0)
 658     ;
 659 #endif
 660   errno = e;
 661 }
 662
 663 /* --- @swrsh@ --- *
 664  *
 665  * Arguments:   @sw_remote *r@ = remote process block to look after
 666  *              @const char *host@ = host to run on (0 for this one)
 667  *              @const char *cmd@ = remote command to run
 668  *              @char *argv[]@ = arguments to pass on
 669  *
 670  * Returns:     Zero if it worked, nonzero if not.
 671  *
 672  * Use:         Runs a command on a remote host.  The argument array is
 673  *              mangled to come out OK at the far end.  The environment and
 674  *              current directory are also passed along, and pop out the
 675  *              other end unmolested.
 676  */
 677
 678 int swrsh(sw_remote *r, const char *host, const char *cmd, char *argv[])
 679 {
 680   int sk[2];
 681   pid_t kid;
 682
 683   /* --- Get a socket pair for communicating with the other end --- */
 684
 685   if (socketpair(PF_UNIX, SOCK_STREAM, 0, sk))
 686     goto tidy_0;
 687
 688   /* --- Set up a signal handler --- */
 689
 690   if (!handler) {
 691     struct sigaction sa;
 692     sa.sa_handler = sigchld;
 693     sa.sa_flags = SA_NOCLDSTOP;
 694 #ifdef SA_RESTART
 695     sa.sa_flags |= SA_RESTART;
 696 #endif
 697     sigemptyset(&sa.sa_mask);
 698     sigaction(SIGCHLD, &sa, 0);
 699     handler = 1;
 700   }
 701
 702   /* --- Fork off a child to cope with stuff --- */
 703
 704   kid = fork();
 705   if (kid < 0)
 706     goto tidy_1;
 707
 708   /* --- Handle the child process --- *
 709    *
 710    * If this is a local job, then just loop around inside to handle the
 711    * `remote' command.  Otherwise crank up `rsh' and pass the command over to
 712    * a remote copy of myself.
 713    *
 714    * (Why do I need a separate process for local jobs?  I don't really, but
 715    * it makes everything much simpler when running multiple jobs at the same
 716    * time.)
 717    */
 718
 719   if (kid == 0) {
 720     close(sk[0]);
 721
 722     /* --- Child end of a local job --- */
 723
 724     signal(SIGINT, SIG_DFL);
 725     signal(SIGQUIT, SIG_DFL);
 726
 727     if (!host) {
 728       r->fdin = r->fdout = sk[1];
 729       remote(r, cmd, argv, environ);
 730     }
 731
 732     /* --- Local child end of a remote job --- */
 733
 734     else {
 735       const char *rsh;
 736       dup2(sk[1], 0);
 737       dup2(sk[1], 1);
 738       dup2(sk[1], 2);
 739       if (sk[1] > 2)
 740         close(sk[1]);
 741       rsh = getenv("SW_RSH");
 742       if (!rsh)
 743         rsh = RSH;
 744       execlp(rsh, rsh, host, PATH_SW, "--remote", cmd, (char *)0);
 745     }
 746
 747     /* --- I don't expect either to come back --- */
 748
 749     _exit(1);
 750   }
 751
 752   /* --- Local sort out of what to do --- *
 753    *
 754    * Either way, I've now got a socket tied to something which speaks my
 755    * communication protocol.  However, if this is a local job, then I can get
 756    * going right away; otherwise, I've got to transmit various bits of
 757    * information over the protocol.
 758    */
 759
 760   r->fdin = r->fdout = sk[0];
 761   close(sk[1]);
 762
 763   if (host) {
 764     char buf[PKMAX];
 765     if (!getcwd(buf, sizeof(buf)))
 766       goto tidy_1;
 767     sendargv(r, PKTYPE_ARGS, argv);
 768     sendargv(r, PKTYPE_ENV, environ);
 769     pksend(r, PKTYPE_DIR, buf, strlen(buf) + 1);
 770     pksend(r, PKTYPE_GO, 0, 0);
 771   }
 772
 773   /* --- Ready to rock'n'roll --- */
 774
 775   r->sz = 0;
 776   return (0);
 777
 778   /* --- Tidy up if it failed --- */
 779
 780 tidy_1:
 781   close(sk[0]);
 782   close(sk[1]);
 783 tidy_0:
 784   return (-1);
 785 }
 786
 787 /*----- Subcommands -------------------------------------------------------*/
 788
 789 /* --- @swrsh_rsh@ --- */
 790
 791 void rsw_rsh(sw_remote *r, char *argv[], char *env[])
 792 {
 793   pid_t kid, k;
 794   int pfd[2];
 795   int status;
 796
 797   /* --- Create a pipe --- */
 798
 799   if (pipe(pfd))
 800     swdie(r, 1, "couldn't create pipe: %s", strerror(errno));
 801
 802   /* --- Start the child process up --- */
 803
 804   kid = fork();
 805   if (kid < 0)
 806     swdie(r, 1, "fork failed: %s", strerror(errno));
 807   else if (kid == 0) {
 808     int fd;
 809
 810     /* --- Use my new environment --- */
 811
 812     environ = env; /* Yuk. */
 813
 814     /* --- Fiddle with pipe file descriptors --- */
 815
 816     close(pfd[0]);
 817     dup2(pfd[1], 1);
 818     dup2(pfd[1], 2);
 819     if (pfd[1] > 2)
 820       close(pfd[1]);
 821
 822     /* --- Make sure it doesn't get any input --- */
 823
 824     close(0);
 825     fd = open("/dev/null", O_RDONLY);
 826     if (fd != 0) {
 827       dup2(fd, 0);
 828       close(fd);
 829     }
 830
 831     /* --- Run the program --- */
 832
 833     execvp(argv[0], argv);
 834     die(1, "couldn't exec `%s': %s", argv[0], strerror(errno));
 835   }
 836
 837   /* --- Read the data from the pipe until it closes --- */
 838
 839   close(pfd[1]);
 840   for (;;) {
 841     ssize_t n = read(pfd[0], r->buf, sizeof(r->buf));
 842     if (n < 0)
 843       swdie(r, 1, "read error: %s", strerror(errno));
 844     else if (!n)
 845       break;
 846     else
 847       pksend(r, PKTYPE_DATA, r->buf, n);
 848   }
 849   close(pfd[0]);
 850
 851   /* --- Finally, reap the exit status and pass it on --- */
 852
 853   for (;;) {
 854     k = wait(&status);
 855     if (k == kid)
 856       break;
 857     if (k < 0)
 858       swdie(r, 1, "error reaping child: %s", strerror(errno));
 859   }
 860   swwait(r, status);
 861 }
 862
 863 /* --- @sw_rsh@ --- */
 864
 865 int sw_rsh(int argc, char *argv[])
 866 {
 867   sw_remote r;
 868   char *h;
 869   int status = 1;
 870
 871   /* --- Check the arguments --- */
 872
 873   if (argc < 3)
 874     die(1, "Usage: rsh HOST|ARCH COMMAND [ARGS...]");
 875
 876   /* --- Translate architecture names into hostnames --- */
 877
 878   if (strcmp(argv[1], "-") == 0)
 879     h = 0;
 880   else {
 881     archent *a = arch_lookup(argv[1], 0);
 882     if (!a)
 883       h = argv[1];
 884     else if (a->flags & archFlag_home)
 885       h = 0;
 886     else
 887       h = a->host;
 888   }
 889
 890   /* --- Start the remote process --- */
 891
 892   if (swrsh(&r, h, "rsh", argv + 2))
 893     die(1, "remote shell failed: %s", strerror(errno));
 894
 895   /* --- Cope with packets from the remote process --- */
 896
 897   fflush(stdout);
 898   for (;;) {
 899     int t = pkrecv(&r);
 900     switch (t) {
 901       case -1:
 902         die(1, "error reading packet: %s", strerror(errno));
 903       case PKTYPE_DATA:
 904         write(STDOUT_FILENO, r.buf, r.sz);
 905         break;
 906       case PKTYPE_STATUS:
 907         r.buf[r.sz] = 0;
 908         if (r.sz > 1) {
 909           status = 127;
 910           moan("command exited due to signal: %s", r.buf);
 911         } else {
 912           status = r.buf[0];
 913             moan("command exited with status %i", r.buf[0]);
 914         }
 915         goto done;
 916       case PKTYPE_EOF:
 917         moan("command exited unexpectedly");
 918         goto done;
 919       default:
 920         die(1, "unexpected packet type");
 921     }
 922   }
 923
 924   /* --- Finished --- */
 925
 926 done:
 927   close(r.fdin);
 928   return (status);
 929 }
 930
 931 /*----- That's all, folks -------------------------------------------------*/