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