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

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