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

   1 /* -*-c-*-
   2  *
   3  * $Id: exec.c,v 1.8 2003/11/29 20:36:07 mdw Exp $
   4  *
   5  * Source and target for executable programs
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the `fw' port forwarder.
  13  *
  14  * `fw' 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  * `fw' 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 `fw'; 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: exec.c,v $
  32  * Revision 1.8  2003/11/29 20:36:07  mdw
  33  * Privileged outgoing connections.
  34  *
  35  * Revision 1.7  2003/01/24 20:12:26  mdw
  36  * Correctly cast uid and gid sentinel values.  Parse full filenames in
  37  * exec arguments (can't do it for program, unfortunately, since the die is
  38  * cast).
  39  *
  40  * Revision 1.6  2002/02/22 23:43:32  mdw
  41  * Call @xfree@ rather than @free@.
  42  *
  43  * Revision 1.5  2002/01/13 14:49:03  mdw
  44  * Track @lbuf@ changes in mLib.
  45  *
  46  * Revision 1.4  2001/02/03 20:30:03  mdw
  47  * Support re-reading config files on SIGHUP.
  48  *
  49  * Revision 1.3  2000/07/01 11:28:52  mdw
  50  * Use new mLib selbuf features.
  51  *
  52  * Revision 1.2  1999/10/22 22:46:17  mdw
  53  * When a non-file endpoint is attached to a file, keep the file endpoint
  54  * open until the nonfile is done.  This stops socket sources from
  55  * resetting their connection limits too early.
  56  *
  57  * Revision 1.1  1999/07/26 23:33:32  mdw
  58  * New sources and targets.
  59  *
  60  */
  61
  62 /*----- Header files ------------------------------------------------------*/
  63
  64 #include "config.h"
  65
  66 #define _GNU_SOURCE
  67
  68 #include <ctype.h>
  69 #include <errno.h>
  70 #include <signal.h>
  71 #include <stdio.h>
  72 #include <stdlib.h>
  73 #include <string.h>
  74
  75 #include <sys/types.h>
  76 #include <sys/stat.h>
  77 #include <unistd.h>
  78 #include <fcntl.h>
  79 #include <sys/wait.h>
  80
  81 #ifdef HAVE_SETRLIMIT
  82 #  include <sys/resource.h>
  83 #endif
  84
  85 #ifndef DECL_ENVIRON
  86   extern char **environ;
  87 #endif
  88
  89 #include <pwd.h>
  90 #include <grp.h>
  91
  92 #include <syslog.h>
  93
  94 #include <mLib/alloc.h>
  95 #include <mLib/dstr.h>
  96 #include <mLib/env.h>
  97 #include <mLib/fdflags.h>
  98 #include <mLib/report.h>
  99 #include <mLib/sel.h>
 100 #include <mLib/selbuf.h>
 101 #include <mLib/sig.h>
 102 #include <mLib/sub.h>
 103 #include <mLib/sym.h>
 104
 105 #include "conf.h"
 106 #include "endpt.h"
 107 #include "exec.h"
 108 #include "fattr.h"
 109 #include "fw.h"
 110 #include "reffd.h"
 111 #include "scan.h"
 112 #include "source.h"
 113 #include "target.h"
 114
 115 /*----- Data structures ---------------------------------------------------*/
 116
 117 /* --- Resource usage --- */
 118
 119 #ifdef HAVE_SETRLIMIT
 120
 121 typedef struct xlimit {
 122 #define R(r, n) struct rlimit n;
 123 #include "rlimits.h"
 124 } xlimit;
 125
 126 #endif
 127
 128 /* --- Environment variable modifications --- */
 129
 130 typedef struct xenv {
 131   struct xenv *next;
 132   unsigned act;
 133   char *name;
 134   char *value;
 135 } xenv;
 136
 137 #define XEA_SET 0u
 138 #define XEA_CLEAR 1u
 139
 140 /* --- Program options --- */
 141
 142 typedef struct xopts {
 143   unsigned ref;
 144   unsigned f;
 145   const char *dir;
 146   const char *root;
 147   uid_t uid;
 148   gid_t gid;
 149   xenv *env;
 150   xenv **etail;
 151 #ifdef HAVE_SETRLIMIT
 152   xlimit xl;
 153 #endif
 154 } xopts;
 155
 156 #define XF_NOLOG 1u
 157
 158 /* --- Executable program arguments --- */
 159
 160 typedef struct xargs {
 161   unsigned ref;
 162   char *file;
 163   char *argv[1];
 164 } xargs;
 165
 166 #define XARGS_SZ(n) (sizeof(xargs) + sizeof(char *) * (n))
 167
 168 /* --- Executable endpoints --- */
 169
 170 typedef struct xept {
 171   endpt e;
 172   struct xept *next, *prev;
 173   pid_t kid;
 174   endpt *f;
 175   char *desc;
 176   int st;
 177   xargs *xa;
 178   xopts *xo;
 179   selbuf err;
 180 } xept;
 181
 182 #define XEF_CLOSE 16u
 183 #define XEF_EXIT 32u
 184
 185 /* --- Executable program data --- */
 186
 187 typedef struct xdata {
 188   xargs *xa;
 189   xopts *xo;
 190 } xdata;
 191
 192 /* --- Executable source block --- */
 193
 194 typedef struct xsource {
 195   source s;
 196   xdata x;
 197 } xsource;
 198
 199 /* --- Executable target block --- */
 200
 201 typedef struct xtarget {
 202   target t;
 203   xdata x;
 204 } xtarget;
 205
 206 /*----- Static variables --------------------------------------------------*/
 207
 208 static xopts exec_opts = { 1, 0, 0, 0, -1, -1, 0, &exec_opts.env };
 209 static xept *xept_list;
 210 static sig xept_sig;
 211 static sym_table env;
 212
 213 /*----- Fiddling about with resource limits -------------------------------*/
 214
 215 #ifdef HAVE_SETRLIMIT
 216
 217 /* --- Table mapping user-level names to OS interface bits --- */
 218
 219 typedef struct rlimit_ent {
 220   const char *name;
 221   const char *rname;
 222   int r;
 223   size_t off;
 224 } rlimit_ent;
 225
 226 static rlimit_ent rlimits[] = {
 227 #define R(r, n) { #n, #r, r, offsetof(xlimit, n) },
 228 #include "rlimits.h"
 229   { 0, 0, 0, 0 }
 230 };
 231
 232 #define RLIMIT(xl, o) ((struct rlimit *)((char *)(xl) + (o)))
 233
 234 /* --- @rlimit_get@ --- *
 235  *
 236  * Arguments:   @xlimit *xl@ = pointer to limit structure
 237  *
 238  * Returns:     ---
 239  *
 240  * Use:         Initializes a limit structure from the current limits.
 241  */
 242
 243 static void rlimit_get(xlimit *xl)
 244 {
 245   rlimit_ent *r;
 246
 247   for (r = rlimits; r->name; r++) {
 248     if (getrlimit(r->r, RLIMIT(xl, r->off))) {
 249       moan("couldn't read %s: %s", r->rname, strerror(errno));
 250       _exit(1);
 251     }
 252   }
 253 }
 254
 255 /* --- @rlimit_set@ --- *
 256  *
 257  * Arguments:   @xlimit *xl@ = pointer to limit structure
 258  *
 259  * Returns:     ---
 260  *
 261  * Use:         Sets resource limits from the supplied limits structure.
 262  */
 263
 264 static void rlimit_set(xlimit *xl)
 265 {
 266   rlimit_ent *r;
 267
 268   for (r = rlimits; r->name; r++) {
 269     if (setrlimit(r->r, RLIMIT(xl, r->off))) {
 270       moan("couldn't set %s: %s", r->rname, strerror(errno));
 271       _exit(1);
 272     }
 273   }
 274 }
 275
 276 /* --- @rlimit_option@ --- */
 277
 278 static int rlimit_option(xlimit *xl, scanner *sc)
 279 {
 280   CONF_BEGIN(sc, "rlimit", "resource limit")
 281   enum { w_soft, w_hard, w_both } which = w_both;
 282   rlimit_ent *chosen;
 283   struct rlimit *rl;
 284   long v;
 285
 286   /* --- Find out which resource is being fiddled --- */
 287
 288   {
 289     rlimit_ent *r;
 290
 291     chosen = 0;
 292     for (r = rlimits; r->name; r++) {
 293       if (strncmp(sc->d.buf, r->name, sc->d.len) == 0) {
 294         if (r->name[sc->d.len] == 0) {
 295           chosen = r;
 296           break;
 297         } else if (chosen)
 298           error(sc, "ambiguous resource limit name `%s'", sc->d.buf);
 299         else if (CONF_QUAL)
 300           chosen = r;
 301       }
 302     }
 303     if (!chosen)
 304       CONF_REJECT;
 305     token(sc);
 306     rl = RLIMIT(xl, chosen->off);
 307   }
 308
 309   /* --- Look for hard or soft restrictions --- */
 310
 311   {
 312     int i;
 313     if (sc->t == '.')
 314       token(sc);
 315     if (sc->t == CTOK_WORD) {
 316       if ((i = conf_enum(sc, "soft,hard",
 317                          ENUM_ABBREV | ENUM_NONE, "limit type")) != -1)
 318         which = i;
 319     }
 320   }
 321
 322   /* --- Now read the new value --- */
 323
 324   if (sc->t == '=')
 325     token(sc);
 326   if (sc->t != CTOK_WORD)
 327     error(sc, "parse error, expected limit value");
 328
 329   if (conf_enum(sc, "unlimited,infinity",
 330                 ENUM_ABBREV | ENUM_NONE, "limit value") > -1)
 331     v = RLIM_INFINITY;
 332   else {
 333     char *p;
 334
 335     v = strtol(sc->d.buf, &p, 0);
 336     if (p == sc->d.buf)
 337       error(sc, "parse error, invalid limit value `%s'", sc->d.buf);
 338     switch (tolower((unsigned char)*p)) {
 339       case 0: break;
 340       case 'b': v *= 512; break;
 341       case 'g': v *= 1024;
 342       case 'm': v *= 1024;
 343       case 'k': v *= 1024; break;
 344       default: error(sc, "parse error, invalid limit scale `%c'", *p);
 345     }
 346     token(sc);
 347   }
 348
 349   /* --- Store the limit value away --- */
 350
 351   switch (which) {
 352     case w_both:
 353       rl->rlim_cur = v;
 354       rl->rlim_max = v;
 355       break;
 356     case w_soft:
 357       if (v > rl->rlim_max)
 358         error(sc, "soft limit %l exceeds hard limit %l for %s",
 359               v, rl->rlim_max, chosen->rname);
 360       rl->rlim_cur = v;
 361       break;
 362     case w_hard:
 363       rl->rlim_max = v;
 364       if (rl->rlim_cur > v)
 365         rl->rlim_cur = v;
 366       break;
 367   }
 368
 369   CONF_ACCEPT;
 370   CONF_END;
 371 }
 372
 373 #endif
 374
 375 /*----- Environment fiddling ----------------------------------------------*/
 376
 377 /* --- @xenv_option@ --- *
 378  *
 379  * Arguments:   @xopts *xo@ = pointer to options block
 380  *              @scanner *sc@ = pointer to scanner
 381  *
 382  * Returns:     Nonzero if claimed
 383  *
 384  * Use:         Parses environment variable assignments.
 385  */
 386
 387 static int xenv_option(xopts *xo, scanner *sc)
 388 {
 389   CONF_BEGIN(sc, "env", "environment")
 390   xenv *xe;
 391
 392   /* --- Unset a variable --- */
 393
 394   if (strcmp(sc->d.buf, "unset") == 0) {
 395     token(sc);
 396     if (sc->t != CTOK_WORD)
 397       error(sc, "parse error, expected environment variable name");
 398     xe = CREATE(xenv);
 399     xe->name = xstrdup(sc->d.buf);
 400     xe->value = 0;
 401     xe->act = XEA_SET;
 402     token(sc);
 403     goto link;
 404   }
 405
 406   /* --- Clear the entire environment --- */
 407
 408   if (strcmp(sc->d.buf, "clear") == 0) {
 409     token(sc);
 410     xe = CREATE(xenv);
 411     xe->act = XEA_CLEAR;
 412     goto link;
 413   }
 414
 415   /* --- Allow `set' to be omitted if there's a prefix --- */
 416
 417   if (strcmp(sc->d.buf, "set") == 0)
 418     token(sc);
 419   else if (!CONF_QUAL)
 420     CONF_REJECT;
 421
 422   /* --- Set a variable --- */
 423
 424   if (sc->t != CTOK_WORD)
 425     error(sc, "parse error, expected environment variable name");
 426   xe = CREATE(xenv);
 427   xe->name = xstrdup(sc->d.buf);
 428   token(sc);
 429   if (sc->t == '=')
 430     token(sc);
 431   if (sc->t != CTOK_WORD)
 432     error(sc, "parse error, expected environment variable value");
 433   xe->value = xstrdup(sc->d.buf);
 434   xe->act = XEA_SET;
 435   token(sc);
 436   goto link;
 437
 438 link:
 439   xe->next = 0;
 440   *xo->etail = xe;
 441   xo->etail = &xe->next;
 442   CONF_ACCEPT;
 443
 444   /* --- Nothing else to try --- */
 445
 446   CONF_END;
 447 }
 448
 449 /* --- @xenv_apply@ --- *
 450  *
 451  * Arguments:   @xenv *xe@ = pointer to a variable change list
 452  *
 453  * Returns:     ---
 454  *
 455  * Use:         Modifies the environment (in @env@) according to the list.
 456  */
 457
 458 static void xenv_apply(xenv *xe)
 459 {
 460   while (xe) {
 461     switch (xe->act) {
 462       case XEA_SET:
 463         env_put(&env, xe->name, xe->value);
 464         break;
 465       case XEA_CLEAR:
 466         env_destroy(&env);
 467         sym_create(&env);
 468         break;
 469     }
 470     xe = xe->next;
 471   }
 472 }
 473
 474 /* --- @xenv_destroy@ --- *
 475  *
 476  * Arguments:   @xenv *xe@ = pointer to a variable change list
 477  *
 478  * Returns:     ---
 479  *
 480  * Use:         Frees the memory used by an environment variable change list.
 481  */
 482
 483 static void xenv_destroy(xenv *xe)
 484 {
 485   while (xe) {
 486     xenv *xxe = xe;
 487     xe = xe->next;
 488     xfree(xxe->name);
 489     if (xxe->value)
 490       xfree(xxe->value);
 491     DESTROY(xxe);
 492   }
 493 }
 494
 495 /*----- Miscellaneous good things -----------------------------------------*/
 496
 497 /* --- @x_tidy@ --- *
 498  *
 499  * Arguments:   @xargs *xa@ = pointer to an arguments block
 500  *              @xopts *xo@ = pointer to an options block
 501  *
 502  * Returns:     ---
 503  *
 504  * Use:         Releases a reference to argument and options blocks.
 505  */
 506
 507 static void x_tidy(xargs *xa, xopts *xo)
 508 {
 509   xa->ref--;
 510   if (!xa->ref)
 511     xfree(xa);
 512
 513   xo->ref--;
 514   if (!xo->ref) {
 515     xenv_destroy(xo->env);
 516     DESTROY(xo);
 517   }
 518 }
 519
 520 /*----- Executable endpoints ----------------------------------------------*/
 521
 522 /* --- @attach@ --- */
 523
 524 static void xept_error(char */*p*/, size_t /*len*/, void */*v*/);
 525
 526 static void xept_attach(endpt *e, reffd *in, reffd *out)
 527 {
 528   xept *xe = (xept *)e;
 529   pid_t kid;
 530   int fd[2];
 531
 532   /* --- Make a pipe for standard error --- */
 533
 534   if (pipe(fd)) {
 535     fw_log(-1, "[%s] couldn't create pipe: %s", xe->desc, strerror(errno));
 536     return;
 537   }
 538   fdflags(fd[0], O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 539
 540   /* --- Fork a child, and handle an error if there was one --- */
 541
 542   if ((kid = fork()) == -1) {
 543     fw_log(-1, "[%s] couldn't fork: %s", xe->desc, strerror(errno));
 544     close(fd[0]);
 545     close(fd[1]);
 546     return;
 547   }
 548
 549   /* --- Do the child thing --- */
 550
 551   if (kid == 0) {
 552     xopts *xo = xe->xo;
 553
 554     /* --- Fiddle with the file descriptors --- *
 555      *
 556      * Attach the other endpoint's descriptors to standard input and output.
 557      * Attach my pipe to standard error.  Mark everything as blocking and
 558      * not-to-be-closed-on-exec at this end.
 559      */
 560
 561     close(fd[0]);
 562     if (dup2(in->fd, STDIN_FILENO) < 0 ||
 563         dup2(out->fd, STDOUT_FILENO) < 0 ||
 564         dup2(fd[1], STDERR_FILENO) < 0) {
 565       moan("couldn't manipulate file descriptors: %s", strerror(errno));
 566       _exit(1);
 567     }
 568
 569     if (in->fd > 2)
 570       close(in->fd);
 571     if (out->fd > 2)
 572       close(out->fd);
 573
 574     fdflags(STDIN_FILENO, O_NONBLOCK, 0, FD_CLOEXEC, 0);
 575     fdflags(STDOUT_FILENO, O_NONBLOCK, 0, FD_CLOEXEC, 0);
 576     fdflags(STDERR_FILENO, O_NONBLOCK, 0, FD_CLOEXEC, 0);
 577
 578     /* --- First of all set the @chroot@ prison --- */
 579
 580     if (xo->root && chroot(xo->root)) {
 581       moan("couldn't set `%s' as filesystem root: %s",
 582            xo->root, strerror(errno));
 583       _exit(1);
 584     }
 585
 586     /* --- Now set the current directory --- */
 587
 588     if (xo->dir ? chdir(xo->dir) : xo->root ? chdir("/") : 0) {
 589       moan("couldn't set `%s' as current directory: %s",
 590            xo->dir ? xo->dir : "/", strerror(errno));
 591       _exit(1);
 592     }
 593
 594     /* --- Set the resource limits --- */
 595
 596 #ifdef HAVE_SETRLIMIT
 597     rlimit_set(&xo->xl);
 598 #endif
 599
 600     /* --- Set group id --- */
 601
 602     if (xo->gid != (gid_t)-1) {
 603       if (setgid(xo->gid)) {
 604         moan("couldn't set gid %i: %s", xo->gid, strerror(errno));
 605         _exit(1);
 606       }
 607 #ifdef HAVE_SETGROUPS
 608       if (setgroups(1, &xo->gid))
 609         moan("warning: couldn't set group list to %i: %s", xo->gid,
 610              strerror(errno));
 611 #endif
 612     }
 613
 614     /* --- Set uid --- */
 615
 616     if (xo->uid != (uid_t)-1) {
 617       if (setuid(xo->uid)) {
 618         moan("couldn't set uid %i: %s", xo->uid, strerror(errno));
 619         _exit(1);
 620       }
 621     }
 622
 623     /* --- Play with signal dispositions --- */
 624
 625     signal(SIGPIPE, SIG_DFL);
 626
 627     /* --- Fiddle with the environment --- */
 628
 629     xenv_apply(exec_opts.env);
 630     xenv_apply(xe->xo->env);
 631     environ = env_export(&env);
 632
 633     /* --- Run the program --- */
 634
 635     execvp(xe->xa->file, xe->xa->argv);
 636     moan("couldn't execute `%s': %s", xe->xa->file, strerror(errno));
 637     _exit(127);
 638   }
 639
 640   /* --- The child's done; see to the parent --- */
 641
 642   xe->kid = kid;
 643   selbuf_init(&xe->err, sel, fd[0], xept_error, xe);
 644   close(fd[1]);
 645   xe->next = xept_list;
 646   xe->prev = 0;
 647   if (xept_list)
 648     xept_list->prev = xe;
 649   xept_list = xe;
 650   if (!(xe->xo->f & XF_NOLOG))
 651     fw_log(-1, "[%s] started with pid %i", xe->desc, kid);
 652   fw_inc();
 653   return;
 654 }
 655
 656 /* --- @xept_file@ --- */
 657
 658 static void xept_file(endpt *e, endpt *f)
 659 {
 660   xept *xe = (xept *)e;
 661   xe->f = f;
 662 }
 663
 664 /* --- @xept_close@ --- */
 665
 666 static void xept_close(endpt *e)
 667 {
 668   xept *xe = (xept *)e;
 669   if (xe->kid == -1) {
 670     if (xe->f)
 671       xe->f->ops->close(xe->f);
 672     x_tidy(xe->xa, xe->xo);
 673     DESTROY(xe);
 674     fw_dec();
 675   }
 676 }
 677
 678 /* --- @xept_destroy@ --- */
 679
 680 static void xept_destroy(xept *xe)
 681 {
 682   /* --- First emit the news about the process --- */
 683
 684   if (xe->xo->f & XF_NOLOG)
 685     /* Nothin' doin' */;
 686   else if (WIFEXITED(xe->st)) {
 687     if (WEXITSTATUS(xe->st) == 0)
 688       fw_log(-1, "[%s] pid %i exited successfully", xe->desc, xe->kid);
 689     else {
 690       fw_log(-1, "[%s] pid %i failed: status %i",
 691              xe->desc, xe->kid, WEXITSTATUS(xe->st));
 692     }
 693   } else if (WIFSIGNALED(xe->st)) {
 694     const char *s;
 695 #ifdef HAVE_STRSIGNAL
 696     s = strsignal(WTERMSIG(xe->st));
 697 #elif HAVE__SYS_SIGLIST
 698     s = _sys_siglist[WTERMSIG(xe->st)];
 699 #else
 700     char buf[32];
 701     sprintf(buf, "signal %i", WTERMSIG(xe->st));
 702     s = buf;
 703 #endif
 704     fw_log(-1, "[%s] pid %i failed: %s", xe->desc, xe->kid, s);
 705   } else
 706     fw_log(-1, "[%s] pid %i failed: unrecognized status", xe->desc, xe->kid);
 707
 708   /* --- Free up the parent-side resources --- */
 709
 710   if (xe->next)
 711     xe->next->prev = xe->prev;
 712   if (xe->prev)
 713     xe->prev->next = xe->next;
 714   else
 715     xept_list = xe->next;
 716
 717   xfree(xe->desc);
 718   if (xe->f)
 719     xe->f->ops->close(xe->f);
 720   x_tidy(xe->xa, xe->xo);
 721   fw_dec();
 722   DESTROY(xe);
 723 }
 724
 725 /* --- @xept_chld@ --- *
 726  *
 727  * Arguments:   @int n@ = signal number
 728  *              @void *p@ = uninteresting pointer
 729  *
 730  * Returns:     ---
 731  *
 732  * Use:         Deals with child death situations.
 733  */
 734
 735 static void xept_chld(int n, void *p)
 736 {
 737   pid_t kid;
 738   int st;
 739
 740   while ((kid = waitpid(-1, &st, WNOHANG)) > 0) {
 741     xept *xe = xept_list;
 742     while (xe) {
 743       xept *xxe = xe;
 744       xe = xe->next;
 745       if (kid == xxe->kid) {
 746         xxe->st = st;
 747         xxe->e.f |= XEF_EXIT;
 748         if (xxe->e.f & XEF_CLOSE)
 749           xept_destroy(xxe);
 750         break;
 751       }
 752     }
 753   }
 754 }
 755
 756 /* --- @xept_error@ --- *
 757  *
 758  * Arguments:   @char *p@ = pointer to string read from stderr
 759  *              @size_t len@ = length of the string
 760  *              @void *v@ = pointer to by endpoint
 761  *
 762  * Returns:     ---
 763  *
 764  * Use:         Handles error reports from a child process.
 765  */
 766
 767 static void xept_error(char *p, size_t len, void *v)
 768 {
 769   xept *xe = v;
 770   if (p)
 771     fw_log(-1, "[%s] pid %i: %s", xe->desc, xe->kid, p);
 772   else {
 773     close(xe->err.reader.fd);
 774     selbuf_destroy(&xe->err);
 775     xe->e.f |= XEF_CLOSE;
 776     if (xe->e.f & XEF_EXIT)
 777       xept_destroy(xe);
 778   }
 779 }
 780
 781 /* --- Endpoint operations --- */
 782
 783 static endpt_ops xept_ops = { xept_attach, xept_file, 0, xept_close };
 784
 785 /*----- General operations on sources and targets -------------------------*/
 786
 787 /* --- @exec_init@ --- *
 788  *
 789  * Arguments:   ---
 790  *
 791  * Returns:     ---
 792  *
 793  * Use:         Initializes the executable problem source and target.
 794  */
 795
 796 void exec_init(void)
 797 {
 798 #ifdef HAVE_SETRLIMIT
 799   rlimit_get(&exec_opts.xl);
 800 #endif
 801   sig_add(&xept_sig, SIGCHLD, xept_chld, 0);
 802   sym_create(&env);
 803   env_import(&env, environ);
 804 }
 805
 806 /* --- @exec_option@ --- */
 807
 808 static int exec_option(xdata *x, scanner *sc)
 809 {
 810   xopts *xo = x ? x->xo : &exec_opts;
 811
 812   CONF_BEGIN(sc, "exec", "executable");
 813
 814   /* --- Logging settings --- */
 815
 816   if (strcmp(sc->d.buf, "logging") == 0 ||
 817       strcmp(sc->d.buf, "log") == 0) {
 818     token(sc);
 819     if (sc->t == '=')
 820       token(sc);
 821     if (conf_enum(sc, "no,yes", ENUM_ABBREV, "logging status"))
 822       xo->f &= ~XF_NOLOG;
 823     else
 824       xo->f |= XF_NOLOG;
 825     CONF_ACCEPT;
 826   }
 827
 828   /* --- Current directory setting --- *
 829    *
 830    * Lots of possibilities to guard against possible brainoes.
 831    */
 832
 833   if (strcmp(sc->d.buf, "dir") == 0 ||
 834       strcmp(sc->d.buf, "cd") == 0 ||
 835       strcmp(sc->d.buf, "chdir") == 0 ||
 836       strcmp(sc->d.buf, "cwd") == 0) {
 837     dstr d = DSTR_INIT;
 838     token(sc);
 839     if (sc->t == '=')
 840       token(sc);
 841     conf_name(sc, '/', &d);
 842     xo->dir = xstrdup(d.buf);
 843     dstr_destroy(&d);
 844     CONF_ACCEPT;
 845   }
 846
 847   /* --- Set a chroot prison --- */
 848
 849   if (strcmp(sc->d.buf, "root") == 0 ||
 850       strcmp(sc->d.buf, "chroot") == 0) {
 851     dstr d = DSTR_INIT;
 852     token(sc);
 853     if (sc->t == '=')
 854       token(sc);
 855     conf_name(sc, '/', &d);
 856     xo->root = xstrdup(d.buf);
 857     dstr_destroy(&d);
 858     CONF_ACCEPT;
 859   }
 860
 861   /* --- Set the target user id --- */
 862
 863   if (strcmp(sc->d.buf, "uid") == 0 ||
 864       strcmp(sc->d.buf, "user") == 0) {
 865     token(sc);
 866     if (sc->t == '=')
 867       token(sc);
 868     if (sc->t != CTOK_WORD)
 869       error(sc, "parse error, expected user name or uid");
 870     if (isdigit((unsigned char)*sc->d.buf))
 871       xo->uid = atoi(sc->d.buf);
 872     else {
 873       struct passwd *pw = getpwnam(sc->d.buf);
 874       if (!pw)
 875         error(sc, "unknown user name `%s'", sc->d.buf);
 876       xo->uid = pw->pw_uid;
 877     }
 878     token(sc);
 879     CONF_ACCEPT;
 880   }
 881
 882   /* --- Set the target group id --- */
 883
 884   if (strcmp(sc->d.buf, "gid") == 0 ||
 885       strcmp(sc->d.buf, "group") == 0) {
 886     token(sc);
 887     if (sc->t == '=')
 888       token(sc);
 889     if (sc->t != CTOK_WORD)
 890       error(sc, "parse error, expected group name or gid");
 891     if (isdigit((unsigned char)*sc->d.buf))
 892       xo->gid = atoi(sc->d.buf);
 893     else {
 894       struct group *gr = getgrnam(sc->d.buf);
 895       if (!gr)
 896         error(sc, "unknown user name `%s'", sc->d.buf);
 897       xo->gid = gr->gr_gid;
 898     }
 899     token(sc);
 900     CONF_ACCEPT;
 901   }
 902
 903   /* --- Now try resource limit settings --- */
 904
 905 #ifdef HAVE_SETRLIMIT
 906   if (rlimit_option(&xo->xl, sc))
 907     CONF_ACCEPT;
 908 #endif
 909
 910   /* --- And then environment settings --- */
 911
 912   if (xenv_option(xo, sc))
 913     CONF_ACCEPT;
 914
 915   /* --- Nothing found --- */
 916
 917   CONF_END;
 918 }
 919
 920 /* --- @exec_desc@ --- */
 921
 922 static void exec_desc(xdata *x, dstr *d)
 923 {
 924   char **p;
 925   char sep = '[';
 926   dstr_puts(d, "exec ");
 927   if (strcmp(x->xa->file, x->xa->argv[0]) != 0) {
 928     dstr_puts(d, x->xa->file);
 929     dstr_putc(d, ' ');
 930   }
 931   for (p = x->xa->argv; *p; p++) {
 932     dstr_putc(d, sep);
 933     dstr_puts(d, *p);
 934     sep = ' ';
 935   }
 936   dstr_putc(d, ']');
 937   dstr_putz(d);
 938 }
 939
 940 /* --- @exec_read@ --- */
 941
 942 static void exec_read(xdata *x, scanner *sc)
 943 {
 944   size_t base = 0;
 945   dstr d = DSTR_INIT;
 946   xargs *xa;
 947
 948   /* --- Read the first word --- *
 949    *
 950    * This is either a shell command or the actual program to run.
 951    */
 952
 953   if (sc->t == CTOK_WORD) {
 954     dstr_putd(&d, &sc->d); d.len++;
 955     base = d.len;
 956     token(sc);
 957   }
 958
 959   /* --- See if there's a list of arguments --- *
 960    *
 961    * If not, then the thing I saw was a shell command, so build the proper
 962    * arguments for that.
 963    */
 964
 965   if (sc->t != '[') {
 966     char *p;
 967     if (!base)
 968       error(sc, "parse error, expected shell command or argument list");
 969     xa = xmalloc(XARGS_SZ(3) + 8 + 3 + d.len);
 970     p = (char *)(xa->argv + 4);
 971     xa->ref = 1;
 972     xa->file = p;
 973     xa->argv[0] = p; memcpy(p, "/bin/sh", 8); p += 8;
 974     xa->argv[1] = p; memcpy(p, "-c", 3); p += 3;
 975     xa->argv[2] = p; memcpy(p, d.buf, d.len); p += d.len;
 976     xa->argv[3] = 0;
 977   }
 978
 979   /* --- Snarf in a list of arguments --- */
 980
 981   else {
 982     int argc = 0;
 983     char *p, *q;
 984     char **v;
 985
 986     /* --- Strip off the leading `[' --- *
 987      *
 988      * Allow various handy filename characters to be entered without quoting.
 989      */
 990
 991     conf_undelim(sc, "=:/.", "=:/.");
 992     token(sc);
 993
 994     /* --- Read a sequence of arguments --- */
 995
 996     while (sc->t == CTOK_WORD) {
 997       dstr_putd(&d, &sc->d); d.len++;
 998       token(sc);
 999       argc++;
1000     }
1001     conf_undelim(sc, 0, 0);
1002
1003     /* --- Expect the closing `]' --- */
1004
1005     if (sc->t != ']')
1006       error(sc, "parse error, missing `]'");
1007     token(sc);
1008
1009     /* --- If there are no arguments, whinge --- */
1010
1011     if (!argc)
1012       error(sc, "must specify at least one argument");
1013
1014     /* --- Allocate a lump of memory for the array --- */
1015
1016     xa = xmalloc(XARGS_SZ(argc) + d.len);
1017     xa->ref = 1;
1018     v = xa->argv;
1019     p = (char *)(v + argc + 1);
1020     memcpy(p, d.buf, d.len);
1021     q = p + d.len;
1022     xa->file = p;
1023     p += base;
1024
1025     /* --- Start dumping addresses into the @argv@ array --- */
1026
1027     for (;;) {
1028       *v++ = p;
1029       while (*p++ && p < q)
1030         ;
1031       if (p >= q)
1032         break;
1033     }
1034     *v++ = 0;
1035   }
1036
1037   /* --- Do some other setting up --- */
1038
1039   dstr_destroy(&d);
1040   x->xa = xa;
1041   x->xo = CREATE(xopts);
1042   *x->xo = exec_opts;
1043   x->xo->ref = 1;
1044   return;
1045 }
1046
1047 /* --- @exec_endpt@ --- */
1048
1049 static endpt *exec_endpt(xdata *x, const char *desc)
1050 {
1051   xept *xe = CREATE(xept);
1052   xe->e.ops = &xept_ops;
1053   xe->e.other = 0;
1054   xe->e.t = 0;
1055   xe->e.f = 0;
1056   xe->xa = x->xa; xe->xa->ref++;
1057   xe->xo = x->xo; xe->xo->ref++;
1058   xe->kid = -1;
1059   xe->f = 0;
1060   xe->desc = xstrdup(desc);
1061   return (&xe->e);
1062 }
1063
1064 /* --- @exec_destroy@ --- */
1065
1066 static void exec_destroy(xdata *x)
1067 {
1068   x_tidy(x->xa, x->xo);
1069 }
1070
1071 /*----- Source definition -------------------------------------------------*/
1072
1073 /* --- @option@ --- */
1074
1075 static int xsource_option(source *s, scanner *sc)
1076 {
1077   xsource *xs = (xsource *)s;
1078   return (exec_option(xs ? &xs->x : 0, sc));
1079 }
1080
1081 /* --- @read@ --- */
1082
1083 static source *xsource_read(scanner *sc)
1084 {
1085   xsource *xs;
1086
1087   if (!conf_prefix(sc, "exec"))
1088     return (0);
1089   xs = CREATE(xsource);
1090   xs->s.ops = &xsource_ops;
1091   xs->s.desc = 0;
1092   exec_read(&xs->x, sc);
1093   return (&xs->s);
1094 }
1095
1096 /* --- @attach@ --- */
1097
1098 static void xsource_destroy(source */*s*/);
1099
1100 static void xsource_attach(source *s, scanner *sc, target *t)
1101 {
1102   xsource *xs = (xsource *)s;
1103   endpt *e, *ee;
1104
1105   /* --- Set up the source description string --- */
1106
1107   {
1108     dstr d = DSTR_INIT;
1109     exec_desc(&xs->x, &d);
1110     dstr_puts(&d, " -> ");
1111     dstr_puts(&d, t->desc);
1112     xs->s.desc = xstrdup(d.buf);
1113     dstr_destroy(&d);
1114   }
1115
1116   /* --- Create the endpoints --- */
1117
1118   if ((ee = t->ops->create(t, xs->s.desc)) == 0)
1119     goto tidy;
1120   if ((e = exec_endpt(&xs->x, xs->s.desc)) == 0) {
1121     ee->ops->close(ee);
1122     goto tidy;
1123   }
1124   endpt_join(e, ee);
1125
1126   /* --- Dispose of source and target --- */
1127
1128 tidy:
1129   t->ops->destroy(t);
1130   xsource_destroy(&xs->s);
1131 }
1132
1133 /* --- @destroy@ --- */
1134
1135 static void xsource_destroy(source *s)
1136 {
1137   xsource *xs = (xsource *)s;
1138   xfree(xs->s.desc);
1139   exec_destroy(&xs->x);
1140   DESTROY(xs);
1141 }
1142
1143 /* --- Executable source operations --- */
1144
1145 source_ops xsource_ops = {
1146   "exec",
1147   xsource_option, xsource_read, xsource_attach, xsource_destroy
1148 };
1149
1150 /*----- Exec target description -------------------------------------------*/
1151
1152 /* --- @option@ --- */
1153
1154 static int xtarget_option(target *t, scanner *sc)
1155 {
1156   xtarget *xt = (xtarget *)t;
1157   return (exec_option(xt ? &xt->x : 0, sc));
1158 }
1159
1160 /* --- @read@ --- */
1161
1162 static target *xtarget_read(scanner *sc)
1163 {
1164   xtarget *xt;
1165   dstr d = DSTR_INIT;
1166
1167   if (!conf_prefix(sc, "exec"))
1168     return (0);
1169   xt = CREATE(xtarget);
1170   xt->t.ops = &xtarget_ops;
1171   exec_read(&xt->x, sc);
1172   exec_desc(&xt->x, &d);
1173   xt->t.desc = xstrdup(d.buf);
1174   dstr_destroy(&d);
1175   return (&xt->t);
1176 }
1177
1178 /* --- @create@ --- */
1179
1180 static endpt *xtarget_create(target *t, const char *desc)
1181 {
1182   xtarget *xt = (xtarget *)t;
1183   endpt *e = exec_endpt(&xt->x, desc);
1184   return (e);
1185 }
1186
1187 /* --- @destroy@ --- */
1188
1189 static void xtarget_destroy(target *t)
1190 {
1191   xtarget *xt = (xtarget *)t;
1192   xfree(xt->t.desc);
1193   exec_destroy(&xt->x);
1194   DESTROY(xt);
1195 }
1196
1197 /* --- Exec target operations --- */
1198
1199 target_ops xtarget_ops = {
1200   "exec",
1201   xtarget_option, xtarget_read, 0, xtarget_create, xtarget_destroy
1202 };
1203
1204 /*----- That's all, folks -------------------------------------------------*/