mdw@git.distorted.org.uk Git - fwd/blob - exec.c

   1 /* -*-c-*-
   2  *
   3  * Source and target for executable programs
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of the `fwd' port forwarder.
  11  *
  12  * `fwd' is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * `fwd' is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with `fwd'; if not, write to the Free Software Foundation,
  24  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 #include "fwd.h"
  28
  29 /*----- Data structures ---------------------------------------------------*/
  30
  31 /* --- Resource usage --- */
  32
  33 #ifdef HAVE_SETRLIMIT
  34
  35 typedef struct xlimit {
  36 #define XLIMIT_ENTRY(name, constant) struct rlimit name;
  37   RLIMITS(XLIMIT_ENTRY)
  38 #undef XLIMIT_ENTRY
  39 } xlimit;
  40
  41 #endif
  42
  43 /* --- Environment variable modifications --- */
  44
  45 typedef struct xenv {
  46   struct xenv *next;
  47   unsigned act;
  48   char *name;
  49   char *value;
  50 } xenv;
  51
  52 #define XEA_SET 0u
  53 #define XEA_CLEAR 1u
  54
  55 /* --- Program options --- */
  56
  57 typedef struct xopts {
  58   unsigned ref;
  59   unsigned f;
  60   const char *dir;
  61   const char *root;
  62   uid_t uid;
  63   gid_t gid;
  64   xenv *env;
  65   xenv **etail;
  66 #ifdef HAVE_SETRLIMIT
  67   xlimit xl;
  68 #endif
  69 } xopts;
  70
  71 #define XF_NOLOG 1u
  72
  73 /* --- Executable program arguments --- */
  74
  75 typedef struct xargs {
  76   unsigned ref;
  77   char *file;
  78   char *argv[1];
  79 } xargs;
  80
  81 #define XARGS_SZ(n) (sizeof(xargs) + sizeof(char *) * (n))
  82
  83 /* --- Executable endpoints --- */
  84
  85 typedef struct xept {
  86   endpt e;
  87   struct xept *next, *prev;
  88   pid_t kid;
  89   endpt *f;
  90   char *desc;
  91   int st;
  92   xargs *xa;
  93   xopts *xo;
  94   selbuf err;
  95 } xept;
  96
  97 #define XEF_CLOSE 16u
  98 #define XEF_EXIT 32u
  99
 100 /* --- Executable program data --- */
 101
 102 typedef struct xdata {
 103   xargs *xa;
 104   xopts *xo;
 105 } xdata;
 106
 107 /* --- Executable source block --- */
 108
 109 typedef struct xsource {
 110   source s;
 111   xdata x;
 112 } xsource;
 113
 114 /* --- Executable target block --- */
 115
 116 typedef struct xtarget {
 117   target t;
 118   xdata x;
 119 } xtarget;
 120
 121 /*----- Static variables --------------------------------------------------*/
 122
 123 static xopts exec_opts = { 1, 0, 0, 0, -1, -1, 0, &exec_opts.env };
 124 static xept *xept_list;
 125 static sig xept_sig;
 126 static sym_table env;
 127
 128 /*----- Fiddling about with resource limits -------------------------------*/
 129
 130 #ifdef HAVE_SETRLIMIT
 131
 132 /* --- Table mapping user-level names to OS interface bits --- */
 133
 134 typedef struct rlimit_ent {
 135   const char *name;
 136   const char *rname;
 137   int r;
 138   size_t off;
 139 } rlimit_ent;
 140
 141 static rlimit_ent rlimits[] = {
 142 #define TABLE_ENTRY(name, constant)                                     \
 143   { #name, #constant, constant, offsetof(xlimit, name) },
 144   RLIMITS(TABLE_ENTRY)
 145 #undef TABLE_ENTRY
 146   { 0, 0, 0, 0 }
 147 };
 148
 149 #define RLIMIT(xl, o) ((struct rlimit *)((char *)(xl) + (o)))
 150
 151 /* --- @rlimit_get@ --- *
 152  *
 153  * Arguments:   @xlimit *xl@ = pointer to limit structure
 154  *
 155  * Returns:     ---
 156  *
 157  * Use:         Initializes a limit structure from the current limits.
 158  */
 159
 160 static void rlimit_get(xlimit *xl)
 161 {
 162   rlimit_ent *r;
 163
 164   for (r = rlimits; r->name; r++) {
 165     if (getrlimit(r->r, RLIMIT(xl, r->off))) {
 166       moan("couldn't read %s: %s", r->rname, strerror(errno));
 167       _exit(1);
 168     }
 169   }
 170 }
 171
 172 /* --- @rlimit_set@ --- *
 173  *
 174  * Arguments:   @xlimit *xl@ = pointer to limit structure
 175  *
 176  * Returns:     ---
 177  *
 178  * Use:         Sets resource limits from the supplied limits structure.
 179  */
 180
 181 static void rlimit_set(xlimit *xl)
 182 {
 183   rlimit_ent *r;
 184
 185   for (r = rlimits; r->name; r++) {
 186     if (setrlimit(r->r, RLIMIT(xl, r->off))) {
 187       moan("couldn't set %s: %s", r->rname, strerror(errno));
 188       _exit(1);
 189     }
 190   }
 191 }
 192
 193 /* --- @rlimit_option@ --- */
 194
 195 static int rlimit_option(xlimit *xl, scanner *sc)
 196 {
 197   CONF_BEGIN(sc, "rlimit", "resource limit")
 198   enum { w_soft, w_hard, w_both } which = w_both;
 199   rlimit_ent *chosen;
 200   struct rlimit *rl;
 201   long v;
 202
 203   /* --- Find out which resource is being fiddled --- */
 204
 205   {
 206     rlimit_ent *r;
 207
 208     chosen = 0;
 209     for (r = rlimits; r->name; r++) {
 210       if (strncmp(sc->d.buf, r->name, sc->d.len) == 0) {
 211         if (r->name[sc->d.len] == 0) {
 212           chosen = r;
 213           break;
 214         } else if (chosen)
 215           error(sc, "ambiguous resource limit name `%s'", sc->d.buf);
 216         else if (CONF_QUAL)
 217           chosen = r;
 218       }
 219     }
 220     if (!chosen)
 221       CONF_REJECT;
 222     token(sc);
 223     rl = RLIMIT(xl, chosen->off);
 224   }
 225
 226   /* --- Look for hard or soft restrictions --- */
 227
 228   {
 229     int i;
 230     if (sc->t == '.')
 231       token(sc);
 232     if (sc->t == CTOK_WORD) {
 233       if ((i = conf_enum(sc, "soft,hard",
 234                          ENUM_ABBREV | ENUM_NONE, "limit type")) != -1)
 235         which = i;
 236     }
 237   }
 238
 239   /* --- Now read the new value --- */
 240
 241   if (sc->t == '=')
 242     token(sc);
 243   if (sc->t != CTOK_WORD)
 244     error(sc, "parse error, expected limit value");
 245
 246   if (conf_enum(sc, "unlimited,infinity",
 247                 ENUM_ABBREV | ENUM_NONE, "limit value") > -1)
 248     v = RLIM_INFINITY;
 249   else {
 250     char *p;
 251
 252     v = strtol(sc->d.buf, &p, 0);
 253     if (p == sc->d.buf)
 254       error(sc, "parse error, invalid limit value `%s'", sc->d.buf);
 255     switch (tolower((unsigned char)*p)) {
 256       case 0: break;
 257       case 'b': v *= 512; break;
 258       case 'g': v *= 1024;
 259       case 'm': v *= 1024;
 260       case 'k': v *= 1024; break;
 261       default: error(sc, "parse error, invalid limit scale `%c'", *p);
 262     }
 263     token(sc);
 264   }
 265
 266   /* --- Store the limit value away --- */
 267
 268   switch (which) {
 269     case w_both:
 270       rl->rlim_cur = v;
 271       rl->rlim_max = v;
 272       break;
 273     case w_soft:
 274       if (v > rl->rlim_max)
 275         error(sc, "soft limit %l exceeds hard limit %l for %s",
 276               v, rl->rlim_max, chosen->rname);
 277       rl->rlim_cur = v;
 278       break;
 279     case w_hard:
 280       rl->rlim_max = v;
 281       if (rl->rlim_cur > v)
 282         rl->rlim_cur = v;
 283       break;
 284   }
 285
 286   CONF_ACCEPT;
 287   CONF_END;
 288 }
 289
 290 #endif
 291
 292 /*----- Environment fiddling ----------------------------------------------*/
 293
 294 /* --- @xenv_option@ --- *
 295  *
 296  * Arguments:   @xopts *xo@ = pointer to options block
 297  *              @scanner *sc@ = pointer to scanner
 298  *
 299  * Returns:     Nonzero if claimed
 300  *
 301  * Use:         Parses environment variable assignments.
 302  */
 303
 304 static int xenv_option(xopts *xo, scanner *sc)
 305 {
 306   CONF_BEGIN(sc, "env", "environment")
 307   xenv *xe;
 308
 309   /* --- Unset a variable --- */
 310
 311   if (strcmp(sc->d.buf, "unset") == 0) {
 312     token(sc);
 313     if (sc->t != CTOK_WORD)
 314       error(sc, "parse error, expected environment variable name");
 315     xe = CREATE(xenv);
 316     xe->name = xstrdup(sc->d.buf);
 317     xe->value = 0;
 318     xe->act = XEA_SET;
 319     token(sc);
 320     goto link;
 321   }
 322
 323   /* --- Clear the entire environment --- */
 324
 325   if (strcmp(sc->d.buf, "clear") == 0) {
 326     token(sc);
 327     xe = CREATE(xenv);
 328     xe->act = XEA_CLEAR;
 329     goto link;
 330   }
 331
 332   /* --- Allow `set' to be omitted if there's a prefix --- */
 333
 334   if (strcmp(sc->d.buf, "set") == 0)
 335     token(sc);
 336   else if (!CONF_QUAL)
 337     CONF_REJECT;
 338
 339   /* --- Set a variable --- */
 340
 341   if (sc->t != CTOK_WORD)
 342     error(sc, "parse error, expected environment variable name");
 343   xe = CREATE(xenv);
 344   xe->name = xstrdup(sc->d.buf);
 345   token(sc);
 346   if (sc->t == '=')
 347     token(sc);
 348   if (sc->t != CTOK_WORD)
 349     error(sc, "parse error, expected environment variable value");
 350   xe->value = xstrdup(sc->d.buf);
 351   xe->act = XEA_SET;
 352   token(sc);
 353   goto link;
 354
 355 link:
 356   xe->next = 0;
 357   *xo->etail = xe;
 358   xo->etail = &xe->next;
 359   CONF_ACCEPT;
 360
 361   /* --- Nothing else to try --- */
 362
 363   CONF_END;
 364 }
 365
 366 /* --- @xenv_apply@ --- *
 367  *
 368  * Arguments:   @xenv *xe@ = pointer to a variable change list
 369  *
 370  * Returns:     ---
 371  *
 372  * Use:         Modifies the environment (in @env@) according to the list.
 373  */
 374
 375 static void xenv_apply(xenv *xe)
 376 {
 377   while (xe) {
 378     switch (xe->act) {
 379       case XEA_SET:
 380         env_put(&env, xe->name, xe->value);
 381         break;
 382       case XEA_CLEAR:
 383         env_destroy(&env);
 384         sym_create(&env);
 385         break;
 386     }
 387     xe = xe->next;
 388   }
 389 }
 390
 391 /* --- @xenv_destroy@ --- *
 392  *
 393  * Arguments:   @xenv *xe@ = pointer to a variable change list
 394  *
 395  * Returns:     ---
 396  *
 397  * Use:         Frees the memory used by an environment variable change list.
 398  */
 399
 400 static void xenv_destroy(xenv *xe)
 401 {
 402   while (xe) {
 403     xenv *xxe = xe;
 404     xe = xe->next;
 405     xfree(xxe->name);
 406     if (xxe->value)
 407       xfree(xxe->value);
 408     DESTROY(xxe);
 409   }
 410 }
 411
 412 /*----- Miscellaneous good things -----------------------------------------*/
 413
 414 /* --- @x_tidy@ --- *
 415  *
 416  * Arguments:   @xargs *xa@ = pointer to an arguments block
 417  *              @xopts *xo@ = pointer to an options block
 418  *
 419  * Returns:     ---
 420  *
 421  * Use:         Releases a reference to argument and options blocks.
 422  */
 423
 424 static void x_tidy(xargs *xa, xopts *xo)
 425 {
 426   xa->ref--;
 427   if (!xa->ref)
 428     xfree(xa);
 429
 430   xo->ref--;
 431   if (!xo->ref) {
 432     xenv_destroy(xo->env);
 433     DESTROY(xo);
 434   }
 435 }
 436
 437 /*----- Executable endpoints ----------------------------------------------*/
 438
 439 /* --- @attach@ --- */
 440
 441 static void xept_error(char */*p*/, size_t /*len*/, void */*v*/);
 442
 443 static void xept_attach(endpt *e, reffd *in, reffd *out)
 444 {
 445   xept *xe = (xept *)e;
 446   pid_t kid;
 447   int fd[2];
 448
 449   /* --- Make a pipe for standard error --- */
 450
 451   if (pipe(fd)) {
 452     fw_log(-1, "[%s] couldn't create pipe: %s", xe->desc, strerror(errno));
 453     return;
 454   }
 455   fdflags(fd[0], O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 456
 457   /* --- Fork a child, and handle an error if there was one --- */
 458
 459   if ((kid = fork()) == -1) {
 460     fw_log(-1, "[%s] couldn't fork: %s", xe->desc, strerror(errno));
 461     close(fd[0]);
 462     close(fd[1]);
 463     return;
 464   }
 465
 466   /* --- Do the child thing --- */
 467
 468   if (kid == 0) {
 469     xopts *xo = xe->xo;
 470     mdup_fd md[3];
 471
 472     /* --- Fiddle with the file descriptors --- *
 473      *
 474      * Attach the other endpoint's descriptors to standard input and output.
 475      * Attach my pipe to standard error.  Mark everything as blocking and
 476      * not-to-be-closed-on-exec at this end.
 477      */
 478
 479     close(fd[0]);
 480     md[0].cur = in->fd;  md[0].want = STDIN_FILENO;
 481     md[1].cur = out->fd; md[1].want = STDOUT_FILENO;
 482     md[2].cur = fd[1];   md[2].want = STDERR_FILENO;
 483     if (mdup(md, 3)) {
 484       moan("couldn't manipulate file descriptors: %s", strerror(errno));
 485       _exit(1);
 486     }
 487
 488     fdflags(STDIN_FILENO, O_NONBLOCK, 0, FD_CLOEXEC, 0);
 489     fdflags(STDOUT_FILENO, O_NONBLOCK, 0, FD_CLOEXEC, 0);
 490     fdflags(STDERR_FILENO, O_NONBLOCK, 0, FD_CLOEXEC, 0);
 491
 492     /* --- First of all set the @chroot@ prison --- */
 493
 494     if (xo->root && chroot(xo->root)) {
 495       moan("couldn't set `%s' as filesystem root: %s",
 496            xo->root, strerror(errno));
 497       _exit(1);
 498     }
 499
 500     /* --- Now set the current directory --- */
 501
 502     if (xo->dir ? chdir(xo->dir) : xo->root ? chdir("/") : 0) {
 503       moan("couldn't set `%s' as current directory: %s",
 504            xo->dir ? xo->dir : "/", strerror(errno));
 505       _exit(1);
 506     }
 507
 508     /* --- Set the resource limits --- */
 509
 510 #ifdef HAVE_SETRLIMIT
 511     rlimit_set(&xo->xl);
 512 #endif
 513
 514     /* --- Set group id --- */
 515
 516     if (xo->gid != (gid_t)-1) {
 517       if (setgid(xo->gid)) {
 518         moan("couldn't set gid %i: %s", xo->gid, strerror(errno));
 519         _exit(1);
 520       }
 521 #ifdef HAVE_SETGROUPS
 522       if (setgroups(1, &xo->gid))
 523         moan("warning: couldn't set group list to %i: %s", xo->gid,
 524              strerror(errno));
 525 #endif
 526     }
 527
 528     /* --- Set uid --- */
 529
 530     if (xo->uid != (uid_t)-1) {
 531       if (setuid(xo->uid)) {
 532         moan("couldn't set uid %i: %s", xo->uid, strerror(errno));
 533         _exit(1);
 534       }
 535     }
 536
 537     /* --- Play with signal dispositions --- */
 538
 539     signal(SIGPIPE, SIG_DFL);
 540
 541     /* --- Fiddle with the environment --- */
 542
 543     xenv_apply(exec_opts.env);
 544     xenv_apply(xe->xo->env);
 545     environ = env_export(&env);
 546
 547     /* --- Run the program --- */
 548
 549     execvp(xe->xa->file, xe->xa->argv);
 550     moan("couldn't execute `%s': %s", xe->xa->file, strerror(errno));
 551     _exit(127);
 552   }
 553
 554   /* --- The child's done; see to the parent --- */
 555
 556   xe->kid = kid;
 557   selbuf_init(&xe->err, sel, fd[0], xept_error, xe);
 558   close(fd[1]);
 559   xe->next = xept_list;
 560   xe->prev = 0;
 561   if (xept_list)
 562     xept_list->prev = xe;
 563   xept_list = xe;
 564   if (!(xe->xo->f & XF_NOLOG))
 565     fw_log(-1, "[%s] started with pid %i", xe->desc, kid);
 566   fw_inc();
 567   return;
 568 }
 569
 570 /* --- @xept_file@ --- */
 571
 572 static void xept_file(endpt *e, endpt *f)
 573 {
 574   xept *xe = (xept *)e;
 575   xe->f = f;
 576 }
 577
 578 /* --- @xept_close@ --- */
 579
 580 static void xept_close(endpt *e)
 581 {
 582   xept *xe = (xept *)e;
 583   if (xe->kid == -1) {
 584     if (xe->f)
 585       xe->f->ops->close(xe->f);
 586     x_tidy(xe->xa, xe->xo);
 587     DESTROY(xe);
 588     fw_dec();
 589   }
 590 }
 591
 592 /* --- @xept_destroy@ --- */
 593
 594 static void xept_destroy(xept *xe)
 595 {
 596   /* --- First emit the news about the process --- */
 597
 598   if (xe->xo->f & XF_NOLOG)
 599     /* Nothin' doin' */;
 600   else if (WIFEXITED(xe->st)) {
 601     if (WEXITSTATUS(xe->st) == 0)
 602       fw_log(-1, "[%s] pid %i exited successfully", xe->desc, xe->kid);
 603     else {
 604       fw_log(-1, "[%s] pid %i failed: status %i",
 605              xe->desc, xe->kid, WEXITSTATUS(xe->st));
 606     }
 607   } else if (WIFSIGNALED(xe->st)) {
 608     const char *s;
 609 #ifdef HAVE_STRSIGNAL
 610     s = strsignal(WTERMSIG(xe->st));
 611 #elif HAVE__SYS_SIGLIST
 612     s = _sys_siglist[WTERMSIG(xe->st)];
 613 #else
 614     char buf[32];
 615     sprintf(buf, "signal %i", WTERMSIG(xe->st));
 616     s = buf;
 617 #endif
 618     fw_log(-1, "[%s] pid %i failed: %s", xe->desc, xe->kid, s);
 619   } else
 620     fw_log(-1, "[%s] pid %i failed: unrecognized status", xe->desc, xe->kid);
 621
 622   /* --- Free up the parent-side resources --- */
 623
 624   if (xe->next)
 625     xe->next->prev = xe->prev;
 626   if (xe->prev)
 627     xe->prev->next = xe->next;
 628   else
 629     xept_list = xe->next;
 630
 631   xfree(xe->desc);
 632   if (xe->f)
 633     xe->f->ops->close(xe->f);
 634   x_tidy(xe->xa, xe->xo);
 635   fw_dec();
 636   DESTROY(xe);
 637 }
 638
 639 /* --- @xept_chld@ --- *
 640  *
 641  * Arguments:   @int n@ = signal number
 642  *              @void *p@ = uninteresting pointer
 643  *
 644  * Returns:     ---
 645  *
 646  * Use:         Deals with child death situations.
 647  */
 648
 649 static void xept_chld(int n, void *p)
 650 {
 651   pid_t kid;
 652   int st;
 653
 654   while ((kid = waitpid(-1, &st, WNOHANG)) > 0) {
 655     xept *xe = xept_list;
 656     while (xe) {
 657       xept *xxe = xe;
 658       xe = xe->next;
 659       if (kid == xxe->kid) {
 660         xxe->st = st;
 661         xxe->e.f |= XEF_EXIT;
 662         if (xxe->e.f & XEF_CLOSE)
 663           xept_destroy(xxe);
 664         break;
 665       }
 666     }
 667   }
 668 }
 669
 670 /* --- @xept_error@ --- *
 671  *
 672  * Arguments:   @char *p@ = pointer to string read from stderr
 673  *              @size_t len@ = length of the string
 674  *              @void *v@ = pointer to by endpoint
 675  *
 676  * Returns:     ---
 677  *
 678  * Use:         Handles error reports from a child process.
 679  */
 680
 681 static void xept_error(char *p, size_t len, void *v)
 682 {
 683   xept *xe = v;
 684   if (p)
 685     fw_log(-1, "[%s] pid %i: %s", xe->desc, xe->kid, p);
 686   else {
 687     close(xe->err.reader.fd);
 688     selbuf_destroy(&xe->err);
 689     xe->e.f |= XEF_CLOSE;
 690     if (xe->e.f & XEF_EXIT)
 691       xept_destroy(xe);
 692   }
 693 }
 694
 695 /* --- Endpoint operations --- */
 696
 697 static endpt_ops xept_ops = { xept_attach, xept_file, 0, xept_close };
 698
 699 /*----- General operations on sources and targets -------------------------*/
 700
 701 /* --- @exec_init@ --- *
 702  *
 703  * Arguments:   ---
 704  *
 705  * Returns:     ---
 706  *
 707  * Use:         Initializes the executable problem source and target.
 708  */
 709
 710 void exec_init(void)
 711 {
 712 #ifdef HAVE_SETRLIMIT
 713   rlimit_get(&exec_opts.xl);
 714 #endif
 715   sig_add(&xept_sig, SIGCHLD, xept_chld, 0);
 716   sym_create(&env);
 717   env_import(&env, environ);
 718 }
 719
 720 /* --- @exec_option@ --- */
 721
 722 static int exec_option(xdata *x, scanner *sc)
 723 {
 724   xopts *xo = x ? x->xo : &exec_opts;
 725
 726   CONF_BEGIN(sc, "exec", "executable");
 727
 728   /* --- Logging settings --- */
 729
 730   if (strcmp(sc->d.buf, "logging") == 0 ||
 731       strcmp(sc->d.buf, "log") == 0) {
 732     token(sc);
 733     if (sc->t == '=')
 734       token(sc);
 735     if (conf_enum(sc, "no,yes", ENUM_ABBREV, "logging status"))
 736       xo->f &= ~XF_NOLOG;
 737     else
 738       xo->f |= XF_NOLOG;
 739     CONF_ACCEPT;
 740   }
 741
 742   /* --- Current directory setting --- *
 743    *
 744    * Lots of possibilities to guard against possible brainoes.
 745    */
 746
 747   if (strcmp(sc->d.buf, "dir") == 0 ||
 748       strcmp(sc->d.buf, "cd") == 0 ||
 749       strcmp(sc->d.buf, "chdir") == 0 ||
 750       strcmp(sc->d.buf, "cwd") == 0) {
 751     dstr d = DSTR_INIT;
 752     token(sc);
 753     if (sc->t == '=')
 754       token(sc);
 755     conf_fname(sc, &d);
 756     xo->dir = xstrdup(d.buf);
 757     dstr_destroy(&d);
 758     CONF_ACCEPT;
 759   }
 760
 761   /* --- Set a chroot prison --- */
 762
 763   if (strcmp(sc->d.buf, "root") == 0 ||
 764       strcmp(sc->d.buf, "chroot") == 0) {
 765     dstr d = DSTR_INIT;
 766     token(sc);
 767     if (sc->t == '=')
 768       token(sc);
 769     conf_fname(sc, &d);
 770     xo->root = xstrdup(d.buf);
 771     dstr_destroy(&d);
 772     CONF_ACCEPT;
 773   }
 774
 775   /* --- Set the target user id --- */
 776
 777   if (strcmp(sc->d.buf, "uid") == 0 ||
 778       strcmp(sc->d.buf, "user") == 0) {
 779     token(sc);
 780     if (sc->t == '=')
 781       token(sc);
 782     if (sc->t != CTOK_WORD)
 783       error(sc, "parse error, expected user name or uid");
 784     if (isdigit((unsigned char)*sc->d.buf))
 785       xo->uid = atoi(sc->d.buf);
 786     else {
 787       struct passwd *pw = getpwnam(sc->d.buf);
 788       if (!pw)
 789         error(sc, "unknown user name `%s'", sc->d.buf);
 790       xo->uid = pw->pw_uid;
 791     }
 792     token(sc);
 793     CONF_ACCEPT;
 794   }
 795
 796   /* --- Set the target group id --- */
 797
 798   if (strcmp(sc->d.buf, "gid") == 0 ||
 799       strcmp(sc->d.buf, "group") == 0) {
 800     token(sc);
 801     if (sc->t == '=')
 802       token(sc);
 803     if (sc->t != CTOK_WORD)
 804       error(sc, "parse error, expected group name or gid");
 805     if (isdigit((unsigned char)*sc->d.buf))
 806       xo->gid = atoi(sc->d.buf);
 807     else {
 808       struct group *gr = getgrnam(sc->d.buf);
 809       if (!gr)
 810         error(sc, "unknown user name `%s'", sc->d.buf);
 811       xo->gid = gr->gr_gid;
 812     }
 813     token(sc);
 814     CONF_ACCEPT;
 815   }
 816
 817   /* --- Now try resource limit settings --- */
 818
 819 #ifdef HAVE_SETRLIMIT
 820   if (rlimit_option(&xo->xl, sc))
 821     CONF_ACCEPT;
 822 #endif
 823
 824   /* --- And then environment settings --- */
 825
 826   if (xenv_option(xo, sc))
 827     CONF_ACCEPT;
 828
 829   /* --- Nothing found --- */
 830
 831   CONF_END;
 832 }
 833
 834 /* --- @exec_desc@ --- */
 835
 836 static void exec_desc(xdata *x, dstr *d)
 837 {
 838   char **p;
 839   char sep = '[';
 840   dstr_puts(d, "exec ");
 841   if (strcmp(x->xa->file, x->xa->argv[0]) != 0) {
 842     dstr_puts(d, x->xa->file);
 843     dstr_putc(d, ' ');
 844   }
 845   for (p = x->xa->argv; *p; p++) {
 846     dstr_putc(d, sep);
 847     dstr_puts(d, *p);
 848     sep = ' ';
 849   }
 850   dstr_putc(d, ']');
 851   dstr_putz(d);
 852 }
 853
 854 /* --- @exec_read@ --- */
 855
 856 static void exec_read(xdata *x, scanner *sc)
 857 {
 858   size_t base = 0;
 859   dstr d = DSTR_INIT;
 860   xargs *xa;
 861
 862   /* --- Read the first word --- *
 863    *
 864    * This is either a shell command or the actual program to run.
 865    */
 866
 867   if (sc->t == CTOK_WORD) {
 868     dstr_putd(&d, &sc->d); d.len++;
 869     base = d.len;
 870     token(sc);
 871   }
 872
 873   /* --- See if there's a list of arguments --- *
 874    *
 875    * If not, then the thing I saw was a shell command, so build the proper
 876    * arguments for that.
 877    */
 878
 879   if (sc->t != '[') {
 880     char *p;
 881     if (!base)
 882       error(sc, "parse error, expected shell command or argument list");
 883     xa = xmalloc(XARGS_SZ(3) + 8 + 3 + d.len);
 884     p = (char *)(xa->argv + 4);
 885     xa->ref = 1;
 886     xa->file = p;
 887     xa->argv[0] = p; memcpy(p, "/bin/sh", 8); p += 8;
 888     xa->argv[1] = p; memcpy(p, "-c", 3); p += 3;
 889     xa->argv[2] = p; memcpy(p, d.buf, d.len); p += d.len;
 890     xa->argv[3] = 0;
 891   }
 892
 893   /* --- Snarf in a list of arguments --- */
 894
 895   else {
 896     int argc = 0;
 897     char *p, *q;
 898     char **v;
 899
 900     /* --- Strip off the leading `[' --- *
 901      *
 902      * Allow various handy filename characters to be entered without quoting.
 903      */
 904
 905     conf_undelim(sc, "=:/.", "=:/.");
 906     token(sc);
 907
 908     /* --- Read a sequence of arguments --- */
 909
 910     while (sc->t == CTOK_WORD) {
 911       dstr_putd(&d, &sc->d); d.len++;
 912       token(sc);
 913       argc++;
 914     }
 915     conf_undelim(sc, 0, 0);
 916
 917     /* --- Expect the closing `]' --- */
 918
 919     if (sc->t != ']')
 920       error(sc, "parse error, missing `]'");
 921     token(sc);
 922
 923     /* --- If there are no arguments, whinge --- */
 924
 925     if (!argc)
 926       error(sc, "must specify at least one argument");
 927
 928     /* --- Allocate a lump of memory for the array --- */
 929
 930     xa = xmalloc(XARGS_SZ(argc) + d.len);
 931     xa->ref = 1;
 932     v = xa->argv;
 933     p = (char *)(v + argc + 1);
 934     memcpy(p, d.buf, d.len);
 935     q = p + d.len;
 936     xa->file = p;
 937     p += base;
 938
 939     /* --- Start dumping addresses into the @argv@ array --- */
 940
 941     for (;;) {
 942       *v++ = p;
 943       while (*p++ && p < q)
 944         ;
 945       if (p >= q)
 946         break;
 947     }
 948     *v++ = 0;
 949   }
 950
 951   /* --- Do some other setting up --- */
 952
 953   dstr_destroy(&d);
 954   x->xa = xa;
 955   x->xo = CREATE(xopts);
 956   *x->xo = exec_opts;
 957   x->xo->ref = 1;
 958   return;
 959 }
 960
 961 /* --- @exec_endpt@ --- */
 962
 963 static endpt *exec_endpt(xdata *x, const char *desc)
 964 {
 965   xept *xe = CREATE(xept);
 966   xe->e.ops = &xept_ops;
 967   xe->e.other = 0;
 968   xe->e.t = 0;
 969   xe->e.f = 0;
 970   xe->xa = x->xa; xe->xa->ref++;
 971   xe->xo = x->xo; xe->xo->ref++;
 972   xe->kid = -1;
 973   xe->f = 0;
 974   xe->desc = xstrdup(desc);
 975   return (&xe->e);
 976 }
 977
 978 /* --- @exec_destroy@ --- */
 979
 980 static void exec_destroy(xdata *x)
 981 {
 982   x_tidy(x->xa, x->xo);
 983 }
 984
 985 /*----- Source definition -------------------------------------------------*/
 986
 987 /* --- @option@ --- */
 988
 989 static int xsource_option(source *s, scanner *sc)
 990 {
 991   xsource *xs = (xsource *)s;
 992   return (exec_option(xs ? &xs->x : 0, sc));
 993 }
 994
 995 /* --- @read@ --- */
 996
 997 static source *xsource_read(scanner *sc)
 998 {
 999   xsource *xs;
1000
1001   if (!conf_prefix(sc, "exec"))
1002     return (0);
1003   xs = CREATE(xsource);
1004   xs->s.ops = &xsource_ops;
1005   xs->s.desc = 0;
1006   exec_read(&xs->x, sc);
1007   return (&xs->s);
1008 }
1009
1010 /* --- @attach@ --- */
1011
1012 static void xsource_destroy(source */*s*/);
1013
1014 static void xsource_attach(source *s, scanner *sc, target *t)
1015 {
1016   xsource *xs = (xsource *)s;
1017   endpt *e, *ee;
1018
1019   /* --- Set up the source description string --- */
1020
1021   {
1022     dstr d = DSTR_INIT;
1023     exec_desc(&xs->x, &d);
1024     dstr_puts(&d, " -> ");
1025     dstr_puts(&d, t->desc);
1026     xs->s.desc = xstrdup(d.buf);
1027     dstr_destroy(&d);
1028   }
1029
1030   /* --- Create the endpoints --- */
1031
1032   if ((ee = t->ops->create(t, xs->s.desc)) == 0)
1033     goto tidy;
1034   if ((e = exec_endpt(&xs->x, xs->s.desc)) == 0) {
1035     ee->ops->close(ee);
1036     goto tidy;
1037   }
1038   endpt_join(e, ee, xs->s.desc);
1039
1040   /* --- Dispose of source and target --- */
1041
1042 tidy:
1043   t->ops->destroy(t);
1044   xsource_destroy(&xs->s);
1045 }
1046
1047 /* --- @destroy@ --- */
1048
1049 static void xsource_destroy(source *s)
1050 {
1051   xsource *xs = (xsource *)s;
1052   xfree(xs->s.desc);
1053   exec_destroy(&xs->x);
1054   DESTROY(xs);
1055 }
1056
1057 /* --- Executable source operations --- */
1058
1059 source_ops xsource_ops = {
1060   "exec",
1061   xsource_option, xsource_read, xsource_attach, xsource_destroy
1062 };
1063
1064 /*----- Exec target description -------------------------------------------*/
1065
1066 /* --- @option@ --- */
1067
1068 static int xtarget_option(target *t, scanner *sc)
1069 {
1070   xtarget *xt = (xtarget *)t;
1071   return (exec_option(xt ? &xt->x : 0, sc));
1072 }
1073
1074 /* --- @read@ --- */
1075
1076 static target *xtarget_read(scanner *sc)
1077 {
1078   xtarget *xt;
1079   dstr d = DSTR_INIT;
1080
1081   if (!conf_prefix(sc, "exec"))
1082     return (0);
1083   xt = CREATE(xtarget);
1084   xt->t.ops = &xtarget_ops;
1085   exec_read(&xt->x, sc);
1086   exec_desc(&xt->x, &d);
1087   xt->t.desc = xstrdup(d.buf);
1088   dstr_destroy(&d);
1089   return (&xt->t);
1090 }
1091
1092 /* --- @create@ --- */
1093
1094 static endpt *xtarget_create(target *t, const char *desc)
1095 {
1096   xtarget *xt = (xtarget *)t;
1097   endpt *e = exec_endpt(&xt->x, desc);
1098   return (e);
1099 }
1100
1101 /* --- @destroy@ --- */
1102
1103 static void xtarget_destroy(target *t)
1104 {
1105   xtarget *xt = (xtarget *)t;
1106   xfree(xt->t.desc);
1107   exec_destroy(&xt->x);
1108   DESTROY(xt);
1109 }
1110
1111 /* --- Exec target operations --- */
1112
1113 target_ops xtarget_ops = {
1114   "exec",
1115   xtarget_option, xtarget_read, 0, xtarget_create, xtarget_destroy
1116 };
1117
1118 /*----- That's all, folks -------------------------------------------------*/