usr/src/cmd/csh/sh.c

   1 /*
   2  * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2016 by Delphix. All rights reserved.
   4  */
   5
   6 /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
   7 /*        All Rights Reserved   */
   8
   9 /*
  10  * Copyright (c) 1980 Regents of the University of California.
  11  * All rights reserved.  The Berkeley Software License Agreement
  12  * specifies the terms and conditions for redistribution.
  13  */
  14
  15 #include <locale.h>
  16 #include "sh.h"
  17 /* #include <sys/ioctl.h> */
  18 #include <fcntl.h>
  19 #include <sys/filio.h>
  20 #include "sh.tconst.h"
  21 #include <pwd.h>
  22 #include <stdlib.h>
  23 #ifdef  TRACE
  24 #include <stdio.h>
  25 #endif
  26
  27 /*
  28  * We use these csh(1) private versions of the select macros, (see select(3C))
  29  * so as not to be limited by the size of struct fd_set (ie 1024).
  30  */
  31 #define CSH_FD_SET(n, p)   ((*((p) + ((n)/NFDBITS))) |= (1 << ((n) % NFDBITS)))
  32 #define CSH_FD_CLR(n, p)   ((*((p) + ((n)/NFDBITS))) &= ~(1 << ((n) % NFDBITS)))
  33 #define CSH_FD_ISSET(n, p) ((*((p) + ((n)/NFDBITS))) & (1 << ((n) % NFDBITS)))
  34 #define CSH_FD_ZERO(p, n)  memset((void *)(p), 0,  (n))
  35
  36 tchar *pathlist[] =     { S_usrbin /* "/usr/bin" */, S_DOT /* "." */, 0 };
  37 tchar *dumphist[] =     { S_history /* "history" */, S_h /* "-h" */, 0, 0 };
  38 tchar *loadhist[] =     { S_source /* "source" */, S_h /* "-h" */,
  39     S_NDOThistory /* "~/.history" */, 0 };
  40 tchar HIST = '!';
  41 tchar HISTSUB = '^';
  42 int     nofile;
  43 bool    reenter;
  44 bool    nverbose;
  45 bool    nexececho;
  46 bool    quitit;
  47 bool    fast;
  48 bool    batch;
  49 bool    prompt = 1;
  50 bool    enterhist = 0;
  51
  52 extern  gid_t getegid(), getgid();
  53 extern  uid_t geteuid(), getuid();
  54 extern tchar **strblktotsblk(/* char **, int */);
  55
  56 extern void hupforegnd(void);
  57 void interactive_hup(void);
  58 void interactive_login_hup(void);
  59
  60 void    importpath(tchar *);
  61 void    srccat(tchar *, tchar *);
  62 void    srccat_inlogin(tchar *, tchar *);
  63 void    srcunit(int, bool, bool);
  64 void    rechist(void);
  65 void    goodbye(void);
  66 void    pintr1(bool);
  67 void    process(bool);
  68 void    dosource(tchar **);
  69 void    mailchk(void);
  70 void    printprompt(void);
  71 void    sigwaiting(void);
  72 void    siglwp(void);
  73 void    initdesc(int, char *[]);
  74 void    initdesc_x(int, char *[], int);
  75 void    closem(void);
  76 void    unsetfd(int);
  77 void    phup(void);
  78
  79 #ifdef  TRACE
  80 FILE *trace;
  81 /*
  82  * Trace routines
  83  */
  84 #define TRACEFILE       "/tmp/trace.XXXXXX"
  85
  86 /*
  87  * Initialize trace file.
  88  * Called from main.
  89  */
  90 void
  91 trace_init(void)
  92 {
  93         char name[128];
  94         char *p;
  95
  96         strcpy(name, TRACEFILE);
  97         p = mktemp(name);
  98         trace = fopen(p, "w");
  99 }
 100
 101 /*
 102  * write message to trace file
 103  */
 104 /*VARARGS1*/
 105 void
 106 tprintf(fmt, a, b, c, d, e, f, g, h, i, j)
 107         char *fmt;
 108 {
 109         if (trace) {
 110                 fprintf(trace, fmt, a, b, c, d, e, f, g, h, i, j);
 111                 fflush(trace);
 112         }
 113 }
 114 #endif
 115
 116 int
 117 main(int c, char **av)
 118 {
 119         tchar **v, *cp, *r;
 120         int f;
 121         struct sigvec osv;
 122         struct sigaction sa;
 123         tchar s_prompt[MAXHOSTNAMELEN+3];
 124         char *c_max_var_len;
 125         int c_max_var_len_size;
 126
 127         /*
 128          * set up the error exit, if there is an error before
 129          * this is done, it will core dump, and we don't
 130          * tolerate core dumps
 131          */
 132         haderr = 0;
 133         setexit();
 134         if (haderr) {
 135                 /*
 136                  *  if were here, there was an error in the csh
 137                  *  startup so just punt
 138                  */
 139                 printf("csh startup error, csh exiting...\n");
 140                 flush();
 141                 exitstat();
 142         }
 143
 144
 145         (void) setlocale(LC_ALL, "");
 146 #if !defined(TEXT_DOMAIN)       /* Should be defined by cc -D */
 147 #define TEXT_DOMAIN "SYS_TEST"  /* Use this only if it weren't */
 148 #endif
 149         (void) textdomain(TEXT_DOMAIN);
 150
 151         /* Copy arguments */
 152         v = strblktotsblk(av, c);
 153
 154         /*
 155          * Initialize paraml list
 156          */
 157         paraml.next = paraml.prev = &paraml;
 158
 159         settimes();                     /* Immed. estab. timing base */
 160
 161         if (eq(v[0], S_aout /* "a.out" */))     /* A.out's are quittable */
 162                 quitit = 1;
 163         uid = getuid();
 164         loginsh = **v == '-';
 165         if (loginsh)
 166                 (void) time(&chktim);
 167
 168         /*
 169          * Move the descriptors to safe places.
 170          * The variable didfds is 0 while we have only FSH* to work with.
 171          * When didfds is true, we have 0,1,2 and prefer to use these.
 172          *
 173          * Also, setup data for csh internal file descriptor book keeping.
 174          */
 175         initdesc(c, av);
 176
 177         /*
 178          * Initialize the shell variables.
 179          * ARGV and PROMPT are initialized later.
 180          * STATUS is also munged in several places.
 181          * CHILD is munged when forking/waiting
 182          */
 183
 184         c_max_var_len_size = snprintf(NULL, 0, "%ld", MAX_VAR_LEN);
 185         c_max_var_len = (char *)xalloc(c_max_var_len_size + 1);
 186         (void) snprintf(c_max_var_len, (c_max_var_len_size + 1),
 187             "%ld", MAX_VAR_LEN);
 188         set(S_SUNW_VARLEN,  strtots(NOSTR, c_max_var_len));
 189         xfree(c_max_var_len);
 190
 191         /* don't do globbing here, just set exact copies */
 192         setNS(S_noglob);
 193
 194         set(S_status /* "status" */, S_0 /* "0" */);
 195         dinit(cp = getenvs_("HOME"));   /* dinit thinks that HOME==cwd in a */
 196                                         /* login shell */
 197         if (cp == NOSTR)
 198                 fast++;                 /* No home -> can't read scripts */
 199         else {
 200                 if (strlen_(cp) >= BUFSIZ - 10) {
 201                         cp = NOSTR;
 202                         fast++;
 203                         printf("%s\n", gettext("Pathname too long"));
 204                         set(S_home /* "home" */, savestr(cp));
 205                         local_setenv(S_HOME, savestr(cp));
 206                 }
 207                 set(S_home /* "home" */, savestr(cp));
 208         }
 209         /*
 210          * Grab other useful things from the environment.
 211          * Should we grab everything??
 212          */
 213         if ((cp = getenvs_("USER")) != NOSTR)
 214                 set(S_user /* "user" */, savestr(cp));
 215         else {
 216                 /*
 217                  * If USER is not defined, set it here.
 218                  */
 219                 struct passwd *pw;
 220                 pw = getpwuid(getuid());
 221
 222                 if (pw != NULL) {
 223                         set(S_user, strtots((tchar *)0, pw->pw_name));
 224                         local_setenv(S_USER, strtots((tchar *)0, pw->pw_name));
 225                 } else if (loginsh) { /* Give up setting USER variable. */
 226         printf("Warning: USER environment variable could not be set.\n");
 227                 }
 228         }
 229         if ((cp = getenvs_("TERM")) != NOSTR)
 230                 set(S_term /* "term" */, savestr(cp));
 231         /*
 232          * Re-initialize path if set in environment
 233          */
 234         if ((cp = getenvs_("PATH")) == NOSTR)
 235                 set1(S_path /* "path" */, saveblk(pathlist), &shvhed);
 236         else
 237                 importpath(cp);
 238         set(S_shell /* "shell" */, S_SHELLPATH);
 239
 240         doldol = putn(getpid());                /* For $$ */
 241
 242         /* restore globbing until the user says otherwise */
 243         unsetv(S_noglob);
 244
 245         /*
 246          * Record the interrupt states from the parent process.
 247          * If the parent is non-interruptible our hand must be forced
 248          * or we (and our children) won't be either.
 249          * Our children inherit termination from our parent.
 250          * We catch it only if we are the login shell.
 251          */
 252                 /* parents interruptibility */
 253         (void) sigvec(SIGINT, NULL, &osv);
 254         parintr = osv.sv_handler;
 255                 /* parents terminability */
 256         (void) sigvec(SIGTERM, NULL, &osv);
 257         parterm = osv.sv_handler;
 258
 259         _signal(SIGLWP, siglwp);
 260         _signal(SIGWAITING, sigwaiting);
 261         if (loginsh) {
 262                 (void) signal(SIGHUP, phup);    /* exit processing on HUP */
 263                 (void) signal(SIGXCPU, phup);   /* ...and on XCPU */
 264                 (void) signal(SIGXFSZ, phup);   /* ...and on XFSZ */
 265         }
 266
 267         /*
 268          * Process the arguments.
 269          *
 270          * Note that processing of -v/-x is actually delayed till after
 271          * script processing.
 272          */
 273         c--, v++;
 274         while (c > 0 && (cp = v[0])[0] == '-' && *++cp != '\0' && !batch) {
 275                 do switch (*cp++) {
 276
 277                 case 'b':               /* -b   Next arg is input file */
 278                         batch++;
 279                         break;
 280
 281                 case 'c':               /* -c   Command input from arg */
 282                         if (c == 1)
 283                                 exit(0);
 284                         c--, v++;
 285                         arginp = v[0];
 286                         prompt = 0;
 287                         nofile++;
 288                         cflg++;
 289                         break;
 290
 291                 case 'e':               /* -e   Exit on any error */
 292                         exiterr++;
 293                         break;
 294
 295                 case 'f':               /* -f   Fast start */
 296                         fast++;
 297                         break;
 298
 299                 case 'i':               /* -i   Interactive, even if !intty */
 300                         intact++;
 301                         nofile++;
 302                         break;
 303
 304                 case 'n':               /* -n   Don't execute */
 305                         noexec++;
 306                         break;
 307
 308                 case 'q':               /* -q   (Undoc'd) ... die on quit */
 309                         quitit = 1;
 310                         break;
 311
 312                 case 's':               /* -s   Read from std input */
 313                         nofile++;
 314                         break;
 315
 316                 case 't':               /* -t   Read one line from input */
 317                         onelflg = 2;
 318                         prompt = 0;
 319                         nofile++;
 320                         break;
 321 #ifdef TRACE
 322                 case 'T':               /* -T   trace switch on */
 323                         trace_init();
 324                         break;
 325 #endif
 326
 327                 case 'v':               /* -v   Echo hist expanded input */
 328                         nverbose = 1;                   /* ... later */
 329                         break;
 330
 331                 case 'x':               /* -x   Echo just before execution */
 332                         nexececho = 1;                  /* ... later */
 333                         break;
 334
 335                 case 'V':               /* -V   Echo hist expanded input */
 336                         setNS(S_verbose /* "verbose" */);       /* NOW! */
 337                         break;
 338
 339                 case 'X':               /* -X   Echo just before execution */
 340                         setNS(S_echo /* "echo" */);             /* NOW! */
 341                         break;
 342
 343                 } while (*cp);
 344                 v++, c--;
 345         }
 346
 347         if (quitit)                     /* With all due haste, for debugging */
 348                 (void) signal(SIGQUIT, SIG_DFL);
 349
 350         /*
 351          * Unless prevented by -c, -i, -s, or -t, if there
 352          * are remaining arguments the first of them is the name
 353          * of a shell file from which to read commands.
 354          */
 355         if (!batch && (uid != geteuid() || getgid() != getegid())) {
 356                 errno = EACCES;
 357                 child++;                        /* So this ... */
 358                 Perror(S_csh /* "csh" */);      /* ... doesn't return */
 359         }
 360
 361         if (nofile == 0 && c > 0) {
 362                 nofile = open_(v[0], 0);
 363                 if (nofile < 0) {
 364                         child++;                /* So this ... */
 365                         Perror(v[0]);           /* ... doesn't return */
 366                 }
 367                 file = v[0];
 368                 SHIN = dmove(nofile, FSHIN);    /* Replace FSHIN */
 369                 (void) fcntl(SHIN, F_SETFD, 1);
 370                 prompt = 0;
 371                 c--, v++;
 372         }
 373
 374         /*
 375          * Consider input a tty if it really is or we are interactive.
 376          */
 377         intty = intact || isatty(SHIN);
 378
 379         /*
 380          * Decide whether we should play with signals or not.
 381          * If we are explicitly told (via -i, or -) or we are a login
 382          * shell (arg0 starts with -) or the input and output are both
 383          * the ttys("csh", or "csh</dev/ttyx>/dev/ttyx")
 384          * Note that in only the login shell is it likely that parent
 385          * may have set signals to be ignored
 386          */
 387         if (loginsh || intact || intty && isatty(SHOUT))
 388                 setintr = 1;
 389 #ifdef TELL
 390         settell();
 391 #endif
 392         /*
 393          * Save the remaining arguments in argv.
 394          */
 395         setq(S_argv /* "argv" */, copyblk(v), &shvhed);
 396
 397         /*
 398          * Set up the prompt.
 399          */
 400         if (prompt) {
 401                 gethostname_(s_prompt, MAXHOSTNAMELEN);
 402                 strcat_(s_prompt,
 403                     uid == 0 ? S_SHARPSP /* "# " */ : S_PERSENTSP /* "% " */);
 404                 set(S_prompt /* "prompt" */, s_prompt);
 405         }
 406
 407         /*
 408          * If we are an interactive shell, then start fiddling
 409          * with the signals; this is a tricky game.
 410          */
 411         shpgrp = getpgid(0);
 412         opgrp = tpgrp = -1;
 413         if (setintr) {
 414                 **av = '-';
 415                 if (!quitit)            /* Wary! */
 416                         (void) signal(SIGQUIT, SIG_IGN);
 417                 (void) signal(SIGINT, pintr);
 418                 (void) sigblock(sigmask(SIGINT));
 419                 (void) signal(SIGTERM, SIG_IGN);
 420
 421                 /*
 422                  * Explicitly terminate foreground jobs and exit if we are
 423                  * interactive shell
 424                  */
 425                 if (loginsh) {
 426                         (void) signal(SIGHUP, interactive_login_hup);
 427                 } else {
 428                         (void) signal(SIGHUP, interactive_hup);
 429                 }
 430
 431                 if (quitit == 0 && arginp == 0) {
 432                         (void) signal(SIGTSTP, SIG_IGN);
 433                         (void) signal(SIGTTIN, SIG_IGN);
 434                         (void) signal(SIGTTOU, SIG_IGN);
 435                         /*
 436                          * Wait till in foreground, in case someone
 437                          * stupidly runs
 438                          *      csh &
 439                          * dont want to try to grab away the tty.
 440                          */
 441                         if (isatty(FSHDIAG))
 442                                 f = FSHDIAG;
 443                         else if (isatty(FSHOUT))
 444                                 f = FSHOUT;
 445                         else if (isatty(OLDSTD))
 446                                 f = OLDSTD;
 447                         else
 448                                 f = -1;
 449 retry:
 450                         if (ioctl(f, TIOCGPGRP,  (char *)&tpgrp) == 0 &&
 451                             tpgrp != -1) {
 452                                 if (tpgrp != shpgrp) {
 453                                         void (*old)() = (void (*)())
 454                                             signal(SIGTTIN, SIG_DFL);
 455                                         (void) kill(0, SIGTTIN);
 456                                         (void) signal(SIGTTIN, old);
 457                                         goto retry;
 458                                 }
 459                                 opgrp = shpgrp;
 460                                 shpgrp = getpid();
 461                                 tpgrp = shpgrp;
 462                                 (void) setpgid(0, shpgrp);
 463                                 (void) ioctl(f, TIOCSPGRP,  (char *)&shpgrp);
 464                                 (void) fcntl(dcopy(f, FSHTTY), F_SETFD, 1);
 465                         } else {
 466 notty:
 467 printf("Warning: no access to tty; thus no job control in this shell...\n");
 468                                 tpgrp = -1;
 469                         }
 470                 }
 471         }
 472         if (setintr == 0 && parintr == SIG_DFL)
 473                 setintr++;
 474
 475         /*
 476          * Set SIGCHLD handler, making sure that reads restart after it runs.
 477          */
 478         sigemptyset(&sa.sa_mask);
 479         sa.sa_handler = pchild;
 480         sa.sa_flags = SA_RESTART;
 481         (void) sigaction(SIGCHLD, &sa, NULL);
 482
 483         /*
 484          * Set an exit here in case of an interrupt or error reading
 485          * the shell start-up scripts.
 486          */
 487         setexit();
 488         haderr = 0;             /* In case second time through */
 489         if (!fast && reenter == 0) {
 490                 reenter++;
 491
 492                 /*
 493                  * If this is a login csh, and /etc/.login exists,
 494                  * source /etc/.login first.
 495                  */
 496                 if (loginsh) {
 497                         tchar tmp_etc[4+1];     /* strlen("/etc")+1 */
 498                         tchar tmp_login[7+1];   /* strlen("/.login")+1 */
 499
 500                         strtots(tmp_etc, "/etc");
 501                         strtots(tmp_login, "/.login");
 502                         srccat_inlogin(tmp_etc, tmp_login);
 503                 }
 504
 505                 /* Will have value("home") here because set fast if don't */
 506                 srccat(value(S_home /* "home" */),
 507                     S_SLADOTcshrc /* "/.cshrc" */);
 508
 509                 /* Hash path */
 510                 if (!fast && !arginp && !onelflg && !havhash)
 511                         dohash(xhash);
 512
 513
 514                 /*
 515                  * Reconstruct the history list now, so that it's
 516                  * available from within .login.
 517                  */
 518                 dosource(loadhist);
 519                 if (loginsh) {
 520                         srccat_inlogin(value(S_home /* "home" */),
 521                             S_SLADOTlogin /* "/.login" */);
 522                 }
 523
 524                 /*
 525                  * To get cdpath hashing $cdpath must have a
 526                  * value, not $CDPATH.  So if after reading
 527                  * the startup files ( .cshrc ), and
 528                  * user has specified a value for cdpath, then
 529                  * cache $cdpath paths. xhash2 is global array
 530                  * for $cdpath caching.
 531                  */
 532                 if (!fast && !arginp && !onelflg && !havhash2)
 533                                 dohash(xhash2);
 534         }
 535
 536         /*
 537          * Now are ready for the -v and -x flags
 538          */
 539         if (nverbose)
 540                 setNS(S_verbose /* "verbose" */);
 541         if (nexececho)
 542                 setNS(S_echo /* "echo" */);
 543
 544         /*
 545          * All the rest of the world is inside this call.
 546          * The argument to process indicates whether it should
 547          * catch "error unwinds".  Thus if we are a interactive shell
 548          * our call here will never return by being blown past on an error.
 549          */
 550         process(setintr);
 551
 552         /*
 553          * Mop-up.
 554          */
 555         if (loginsh) {
 556                 printf("logout\n");
 557                 (void) close(SHIN);     /* No need for unsetfd(). */
 558                 child++;
 559                 goodbye();
 560         }
 561         rechist();
 562         exitstat();
 563 }
 564
 565 void
 566 untty(void)
 567 {
 568
 569         if (tpgrp > 0) {
 570                 (void) setpgid(0, opgrp);
 571                 (void) ioctl(FSHTTY, TIOCSPGRP,  (char *)&opgrp);
 572         }
 573 }
 574
 575 void
 576 importpath(tchar *cp)
 577 {
 578         int i = 0;
 579         tchar *dp;
 580         tchar **pv;
 581         int c;
 582         static tchar dot[2] = {'.', 0};
 583
 584         for (dp = cp; *dp; dp++)
 585                 if (*dp == ':')
 586                         i++;
 587         /*
 588          * i+2 where i is the number of colons in the path.
 589          * There are i+1 directories in the path plus we need
 590          * room for a zero terminator.
 591          */
 592         pv =  (tchar **)xcalloc((unsigned)(i + 2), sizeof (tchar **));
 593         dp = cp;
 594         i = 0;
 595         if (*dp)
 596         for (;;) {
 597                 if ((c = *dp) == ':' || c == 0) {
 598                         *dp = 0;
 599                         pv[i++] = savestr(*cp ? cp : dot);
 600                         if (c) {
 601                                 cp = dp + 1;
 602                                 *dp = ':';
 603                         } else
 604                                 break;
 605                 }
 606                 dp++;
 607         }
 608         pv[i] = 0;
 609         set1(S_path /* "path" */, pv, &shvhed);
 610 }
 611
 612 /*
 613  * Source to the file which is the catenation of the argument names.
 614  */
 615 void
 616 srccat(tchar *cp, tchar *dp)
 617 {
 618         tchar *ep = strspl(cp, dp);
 619         int unit = dmove(open_(ep, 0), -1);
 620
 621         (void) fcntl(unit, F_SETFD, 1);
 622         xfree(ep);
 623 #ifdef INGRES
 624         srcunit(unit, 0, 0);
 625 #else
 626         srcunit(unit, 1, 0);
 627 #endif
 628 }
 629
 630 /*
 631  * Source to the file which is the catenation of the argument names.
 632  *      This one does not check the ownership.
 633  */
 634 void
 635 srccat_inlogin(tchar *cp, tchar *dp)
 636 {
 637         tchar *ep = strspl(cp, dp);
 638         int unit = dmove(open_(ep, 0), -1);
 639
 640         (void) fcntl(unit, F_SETFD, 1);
 641         xfree(ep);
 642         srcunit(unit, 0, 0);
 643 }
 644
 645 /*
 646  * Source to a unit.  If onlyown it must be our file or our group or
 647  * we don't chance it.  This occurs on ".cshrc"s and the like.
 648  */
 649 void
 650 srcunit(int unit, bool onlyown, bool hflg)
 651 {
 652         /* We have to push down a lot of state here */
 653         /* All this could go into a structure */
 654         int oSHIN = -1, oldintty = intty;
 655         struct whyle *oldwhyl = whyles;
 656         tchar *ogointr = gointr, *oarginp = arginp;
 657         tchar *oevalp = evalp, **oevalvec = evalvec;
 658         int oonelflg = onelflg;
 659         bool oenterhist = enterhist;
 660         tchar OHIST = HIST;
 661 #ifdef TELL
 662         bool otell = cantell;
 663 #endif
 664         struct Bin saveB;
 665
 666         /* The (few) real local variables */
 667         jmp_buf oldexit;
 668         int reenter, omask;
 669
 670         if (unit < 0)
 671                 return;
 672         if (didfds)
 673                 donefds();
 674         if (onlyown) {
 675                 struct stat stb;
 676
 677                 if (fstat(unit, &stb) < 0 ||
 678                     (stb.st_uid != uid && stb.st_gid != getgid())) {
 679                         (void) close(unit);
 680                         unsetfd(unit);
 681                         return;
 682                 }
 683         }
 684
 685         /*
 686          * There is a critical section here while we are pushing down the
 687          * input stream since we have stuff in different structures.
 688          * If we weren't careful an interrupt could corrupt SHIN's Bin
 689          * structure and kill the shell.
 690          *
 691          * We could avoid the critical region by grouping all the stuff
 692          * in a single structure and pointing at it to move it all at
 693          * once.  This is less efficient globally on many variable references
 694          * however.
 695          */
 696         getexit(oldexit);
 697         reenter = 0;
 698         if (setintr)
 699                 omask = sigblock(sigmask(SIGINT));
 700         setexit();
 701         reenter++;
 702         if (reenter == 1) {
 703                 /* Setup the new values of the state stuff saved above */
 704                 copy((char *)&saveB, (char *)&B, sizeof (saveB));
 705                 fbuf =  (tchar **) 0;
 706                 fseekp = feobp = fblocks = 0;
 707                 oSHIN = SHIN, SHIN = unit, arginp = 0, onelflg = 0;
 708                 intty = isatty(SHIN), whyles = 0, gointr = 0;
 709                 evalvec = 0; evalp = 0;
 710                 enterhist = hflg;
 711                 if (enterhist)
 712                         HIST = '\0';
 713                 /*
 714                  * Now if we are allowing commands to be interrupted,
 715                  * we let ourselves be interrupted.
 716                  */
 717                 if (setintr)
 718                         (void) sigsetmask(omask);
 719 #ifdef TELL
 720                 settell();
 721 #endif
 722                 process(0);             /* 0 -> blow away on errors */
 723         }
 724         if (setintr)
 725                 (void) sigsetmask(omask);
 726         if (oSHIN >= 0) {
 727                 int i;
 728
 729                 /* We made it to the new state... free up its storage */
 730                 /* This code could get run twice but xfree doesn't care */
 731                 for (i = 0; i < fblocks; i++)
 732                         xfree(fbuf[i]);
 733                 xfree((char *)fbuf);
 734
 735                 /* Reset input arena */
 736                 copy((char *)&B, (char *)&saveB, sizeof (B));
 737
 738                 (void) close(SHIN), SHIN = oSHIN;
 739                 unsetfd(SHIN);
 740                 arginp = oarginp, onelflg = oonelflg;
 741                 evalp = oevalp, evalvec = oevalvec;
 742                 intty = oldintty, whyles = oldwhyl, gointr = ogointr;
 743                 if (enterhist)
 744                         HIST = OHIST;
 745                 enterhist = oenterhist;
 746 #ifdef TELL
 747                 cantell = otell;
 748 #endif
 749         }
 750
 751         resexit(oldexit);
 752         /*
 753          * If process reset() (effectively an unwind) then
 754          * we must also unwind.
 755          */
 756         if (reenter >= 2)
 757                 error(NULL);
 758 }
 759
 760 void
 761 rechist(void)
 762 {
 763         tchar buf[BUFSIZ];
 764         int fp, ftmp, oldidfds;
 765
 766         if (!fast) {
 767                 if (value(S_savehist /* "savehist" */)[0] == '\0')
 768                         return;
 769                 (void) strcpy_(buf, value(S_home /* "home" */));
 770                 (void) strcat_(buf, S_SLADOThistory /* "/.history" */);
 771                 fp = creat_(buf, 0666);
 772                 if (fp == -1)
 773                         return;
 774                 oldidfds = didfds;
 775                 didfds = 0;
 776                 ftmp = SHOUT;
 777                 SHOUT = fp;
 778                 (void) strcpy_(buf, value(S_savehist /* "savehist" */));
 779                 dumphist[2] = buf;
 780                 dohist(dumphist);
 781                 (void) close(fp);
 782                 unsetfd(fp);
 783                 SHOUT = ftmp;
 784                 didfds = oldidfds;
 785         }
 786 }
 787
 788 void
 789 goodbye(void)
 790 {
 791         if (loginsh) {
 792                 (void) signal(SIGQUIT, SIG_IGN);
 793                 (void) signal(SIGINT, SIG_IGN);
 794                 (void) signal(SIGTERM, SIG_IGN);
 795                 setintr = 0;            /* No interrupts after "logout" */
 796                 if (adrof(S_home /* "home" */))
 797                         srccat(value(S_home /* "home" */),
 798                             S_SLADOTlogout /* "/.logout" */);
 799         }
 800         rechist();
 801         exitstat();
 802 }
 803
 804 void
 805 exitstat(void)
 806 {
 807
 808 #ifdef PROF
 809         monitor(0);
 810 #endif
 811         /*
 812          * Note that if STATUS is corrupted (i.e. getn bombs)
 813          * then error will exit directly because we poke child here.
 814          * Otherwise we might continue unwarrantedly (sic).
 815          */
 816         child++;
 817         untty();
 818         exit(getn(value(S_status /* "status" */)));
 819 }
 820
 821 /*
 822  * in the event of a HUP we want to save the history
 823  */
 824 void
 825 phup(void)
 826 {
 827         rechist();
 828         exit(1);
 829 }
 830
 831 void
 832 interactive_hup(void)
 833 {
 834         hupforegnd();
 835         exit(1);
 836 }
 837
 838 void
 839 interactive_login_hup(void)
 840 {
 841         rechist();
 842         hupforegnd();
 843         exit(1);
 844 }
 845
 846 tchar *jobargv[2] = { S_jobs /* "jobs" */, 0 };
 847 /*
 848  * Catch an interrupt, e.g. during lexical input.
 849  * If we are an interactive shell, we reset the interrupt catch
 850  * immediately.  In any case we drain the shell output,
 851  * and finally go through the normal error mechanism, which
 852  * gets a chance to make the shell go away.
 853  */
 854 void
 855 pintr(void)
 856 {
 857         pintr1(1);
 858 }
 859
 860 void
 861 pintr1(bool wantnl)
 862 {
 863         tchar **v;
 864         int omask;
 865
 866         omask = sigblock(0);
 867         if (setintr) {
 868                 (void) sigsetmask(omask & ~sigmask(SIGINT));
 869                 if (pjobs) {
 870                         pjobs = 0;
 871                         printf("\n");
 872                         dojobs(jobargv);
 873                         bferr("Interrupted");
 874                 }
 875         }
 876         (void) sigsetmask(omask & ~sigmask(SIGCHLD));
 877         draino();
 878
 879         /*
 880          * If we have an active "onintr" then we search for the label.
 881          * Note that if one does "onintr -" then we shan't be interruptible
 882          * so we needn't worry about that here.
 883          */
 884         if (gointr) {
 885                 search(ZGOTO, 0, gointr);
 886                 timflg = 0;
 887                 if (v = pargv)
 888                         pargv = 0, blkfree(v);
 889                 if (v = gargv)
 890                         gargv = 0, blkfree(v);
 891                 reset();
 892         } else if (intty && wantnl)
 893                 printf("\n");           /* Some like this, others don't */
 894         error(NULL);
 895 }
 896
 897 /*
 898  * Process is the main driving routine for the shell.
 899  * It runs all command processing, except for those within { ... }
 900  * in expressions (which is run by a routine evalav in sh.exp.c which
 901  * is a stripped down process), and `...` evaluation which is run
 902  * also by a subset of this code in sh.glob.c in the routine backeval.
 903  *
 904  * The code here is a little strange because part of it is interruptible
 905  * and hence freeing of structures appears to occur when none is necessary
 906  * if this is ignored.
 907  *
 908  * Note that if catch is not set then we will unwind on any error.
 909  * If an end-of-file occurs, we return.
 910  */
 911 void
 912 process(bool catch)
 913 {
 914         jmp_buf osetexit;
 915         struct command *t;
 916
 917         getexit(osetexit);
 918         for (;;) {
 919                 pendjob();
 920                 freelex(&paraml);
 921                 paraml.next = paraml.prev = &paraml;
 922                 paraml.word = S_ /* "" */;
 923                 t = 0;
 924                 setexit();
 925                 justpr = enterhist;     /* execute if not entering history */
 926
 927                 /*
 928                  * Interruptible during interactive reads
 929                  */
 930                 if (setintr)
 931                         (void) sigsetmask(sigblock(0) & ~sigmask(SIGINT));
 932
 933                 /*
 934                  * For the sake of reset()
 935                  */
 936                 freelex(&paraml), freesyn(t), t = 0;
 937
 938                 if (haderr) {
 939                         if (!catch) {
 940                                 /* unwind */
 941                                 doneinp = 0;
 942                                 resexit(osetexit);
 943                                 reset();
 944                         }
 945                         haderr = 0;
 946                         /*
 947                          * Every error is eventually caught here or
 948                          * the shell dies.  It is at this
 949                          * point that we clean up any left-over open
 950                          * files, by closing all but a fixed number
 951                          * of pre-defined files.  Thus routines don't
 952                          * have to worry about leaving files open due
 953                          * to deeper errors... they will get closed here.
 954                          */
 955                         closem();
 956                         continue;
 957                 }
 958                 if (doneinp) {
 959                         doneinp = 0;
 960                         break;
 961                 }
 962                 if (chkstop)
 963                         chkstop--;
 964                 if (neednote)
 965                         pnote();
 966                 if (intty && prompt && evalvec == 0) {
 967                         mailchk();
 968                         /*
 969                          * If we are at the end of the input buffer
 970                          * then we are going to read fresh stuff.
 971                          * Otherwise, we are rereading input and don't
 972                          * need or want to prompt.
 973                          */
 974                         if (fseekp == feobp)
 975                                 printprompt();
 976                 }
 977                 err = 0;
 978
 979                 /*
 980                  * Echo not only on VERBOSE, but also with history expansion.
 981                  */
 982                 if (lex(&paraml) && intty ||
 983                     adrof(S_verbose /* "verbose" */)) {
 984                         haderr = 1;
 985                         prlex(&paraml);
 986                         haderr = 0;
 987                 }
 988
 989                 /*
 990                  * The parser may lose space if interrupted.
 991                  */
 992                 if (setintr)
 993                         (void) sigblock(sigmask(SIGINT));
 994
 995                 /*
 996                  * Save input text on the history list if
 997                  * reading in old history, or it
 998                  * is from the terminal at the top level and not
 999                  * in a loop.
1000                  */
1001                 if (enterhist || catch && intty && !whyles)
1002                         savehist(&paraml);
1003
1004                 /*
1005                  * Print lexical error messages, except when sourcing
1006                  * history lists.
1007                  */
1008                 if (!enterhist && err)
1009                         error("%s", gettext(err));
1010
1011                 /*
1012                  * If had a history command :p modifier then
1013                  * this is as far as we should go
1014                  */
1015                 if (justpr)
1016                         reset();
1017
1018                 alias(&paraml);
1019
1020                 /*
1021                  * Parse the words of the input into a parse tree.
1022                  */
1023                 t = syntax(paraml.next, &paraml, 0);
1024                 if (err)
1025                         error("%s", gettext(err));
1026
1027                 /*
1028                  * Execute the parse tree
1029                  */
1030                 {
1031                         /*
1032                          * POSIX requires SIGCHLD to be held
1033                          * until all processes have joined the
1034                          * process group in order to avoid race
1035                          * condition.
1036                          */
1037                         int omask;
1038
1039                         omask = sigblock(sigmask(SIGCHLD));
1040                         execute(t, tpgrp);
1041                         (void) sigsetmask(omask &~ sigmask(SIGCHLD));
1042                 }
1043
1044                 if (err)
1045                         error("%s", gettext(err));
1046                 /*
1047                  * Made it!
1048                  */
1049                 freelex(&paraml), freesyn(t);
1050         }
1051         resexit(osetexit);
1052 }
1053
1054 void
1055 dosource(tchar **t)
1056 {
1057         tchar *f;
1058         int u;
1059         bool hflg = 0;
1060         tchar buf[BUFSIZ];
1061
1062         t++;
1063         if (*t && eq(*t, S_h /* "-h" */)) {
1064                 if (*++t == NOSTR)
1065                         bferr("Too few arguments.");
1066                 hflg++;
1067         }
1068         (void) strcpy_(buf, *t);
1069         f = globone(buf);
1070         u = dmove(open_(f, 0), -1);
1071         xfree(f);
1072         freelex(&paraml);
1073         if (u < 0 && !hflg)
1074                 Perror(f);
1075         (void) fcntl(u, F_SETFD, 1);
1076         srcunit(u, 0, hflg);
1077 }
1078
1079 /*
1080  * Check for mail.
1081  * If we are a login shell, then we don't want to tell
1082  * about any mail file unless its been modified
1083  * after the time we started.
1084  * This prevents us from telling the user things they already
1085  * know, since the login program insists on saying
1086  * "You have mail."
1087  */
1088 void
1089 mailchk(void)
1090 {
1091         struct varent *v;
1092         tchar **vp;
1093         time_t t;
1094         int intvl, cnt;
1095         struct stat stb;
1096         bool new;
1097
1098         v = adrof(S_mail /* "mail" */);
1099         if (v == 0)
1100                 return;
1101         (void) time(&t);
1102         vp = v->vec;
1103         cnt = blklen(vp);
1104         intvl = (cnt && number(*vp)) ? (--cnt, getn(*vp++)) : MAILINTVL;
1105         if (intvl < 1)
1106                 intvl = 1;
1107         if (chktim + intvl > t)
1108                 return;
1109         for (; *vp; vp++) {
1110                 if (stat_(*vp, &stb) < 0)
1111                         continue;
1112                 new = stb.st_mtime > time0.tv_sec;
1113                 if (stb.st_size == 0 || stb.st_atime >= stb.st_mtime ||
1114                     (stb.st_atime <= chktim && stb.st_mtime <= chktim) ||
1115                     loginsh && !new)
1116                         continue;
1117                 if (cnt == 1)
1118                         printf("You have %smail.\n", new ? "new " : "");
1119                 else
1120                         printf("%s in %t.\n", new ? "New mail" : "Mail", *vp);
1121         }
1122         chktim = t;
1123 }
1124
1125 /*
1126  * Extract a home directory from the password file
1127  * The argument points to a buffer where the name of the
1128  * user whose home directory is sought is currently.
1129  * We write the home directory of the user back there.
1130  */
1131 int
1132 gethdir(tchar *home)
1133 {
1134         /* getpwname will not be modified, so we need temp. buffer */
1135         char home_str[BUFSIZ];
1136         tchar home_ts[BUFSIZ];
1137         struct passwd *pp /* = getpwnam(home) */;
1138
1139         pp = getpwnam(tstostr(home_str, home));
1140         if (pp == 0)
1141                 return (1);
1142         (void) strcpy_(home, strtots(home_ts, pp->pw_dir));
1143         return (0);
1144 }
1145
1146
1147 #if 0
1148 void
1149 #ifdef PROF
1150 done(int i)
1151 #else
1152 exit(int i)
1153 #endif
1154 {
1155
1156         untty();
1157         _exit(i);
1158 }
1159 #endif
1160
1161 void
1162 printprompt(void)
1163 {
1164         tchar *cp;
1165
1166         if (!whyles) {
1167                 /*
1168                  * Print the prompt string
1169                  */
1170                 for (cp = value(S_prompt /* "prompt" */); *cp; cp++)
1171                         if (*cp == HIST)
1172                                 printf("%d", eventno + 1);
1173                         else {
1174                                 if (*cp == '\\' && cp[1] == HIST)
1175                                         cp++;
1176                                 Putchar(*cp | QUOTE);
1177                         }
1178         } else
1179                 /*
1180                  * Prompt for forward reading loop
1181                  * body content.
1182                  */
1183                 printf("? ");
1184         flush();
1185 }
1186
1187 /*
1188  * Save char * block.
1189  */
1190 tchar **
1191 strblktotsblk(char **v, int num)
1192 {
1193         tchar **newv =
1194             (tchar **)xcalloc((unsigned)(num+ 1), sizeof (tchar **));
1195         tchar **onewv = newv;
1196
1197         while (*v && num--)
1198                 *newv++ = strtots(NOSTR, *v++);
1199         *newv = 0;
1200         return (onewv);
1201 }
1202
1203 void
1204 sigwaiting(void)
1205 {
1206         _signal(SIGWAITING, sigwaiting);
1207 }
1208
1209 void
1210 siglwp(void)
1211 {
1212         _signal(SIGLWP, siglwp);
1213 }
1214
1215
1216 /*
1217  * Following functions and data are used for csh to do its
1218  * file descriptors book keeping.
1219  */
1220
1221 static int *fdinuse = NULL;     /* The list of files opened by csh */
1222 static int nbytesused = 0;      /* no of bytes allocated to fdinuse */
1223 static int max_fd = 0;          /* The maximum descriptor in fdinuse */
1224 static int my_pid;              /* The process id set in initdesc() */
1225 static int NoFile = NOFILE;     /* The number of files I can use. */
1226
1227 /*
1228  * Get the number of files this csh can use.
1229  *
1230  * Move the initial descriptors to their eventual
1231  * resting places, closing all other units.
1232  *
1233  * Also, reserve 0/1/2, so NIS+ routines do not get
1234  * hold of them. And initialize fdinuse list and set
1235  * the current process id.
1236  *
1237  * If this csh was invoked from setuid'ed script file,
1238  * do not close the third argument passed. The file
1239  * must be one of /dev/fd/0,1,2,,,
1240  *      (execv() always passes three arguments when it execs a script
1241  *       file in a form of #! /bin/csh -b.)
1242  *
1243  * If is_reinit is set in initdesc_x(), then we only close the file
1244  * descriptors that we actually opened (as recorded in fdinuse).
1245  */
1246 void
1247 initdesc(int argc, char *argv[])
1248 {
1249         initdesc_x(argc, argv, 0);
1250 }
1251
1252 void
1253 reinitdesc(int argc, char *argv[])
1254 {
1255         initdesc_x(argc, argv, 1);
1256 }
1257
1258 /*
1259  * Callback functions for closing all file descriptors.
1260  */
1261 static int
1262 close_except(void *cd, int fd)
1263 {
1264         int script_fd = *(int *)cd;
1265
1266         if (fd >= 3 && fd < NoFile && fd != script_fd)
1267                 (void) close(fd);
1268         return (0);
1269 }
1270
1271 static int
1272 close_inuse(void *cd, int fd)
1273 {
1274         int script_fd = *(int *)cd;
1275
1276         if (fd >= 3 && fd < NoFile && fd != script_fd &&
1277             CSH_FD_ISSET(fd, fdinuse)) {
1278                 (void) close(fd);
1279                 unsetfd(fd);
1280         }
1281         return (0);
1282 }
1283
1284 void
1285 initdesc_x(int argc, char *argv[], int is_reinit)
1286 {
1287
1288         int script_fd = -1;
1289         struct stat buf;
1290         struct rlimit rlp;
1291
1292         /*
1293          * Get pid of this shell
1294          */
1295         my_pid = getpid();
1296
1297         /*
1298          * Get the hard limit numbers of descriptors
1299          * this csh can use.
1300          */
1301         if (getrlimit(RLIMIT_NOFILE, &rlp) == 0)
1302                 NoFile = rlp.rlim_cur;
1303
1304         /*
1305          * If this csh was invoked for executing setuid script file,
1306          * the third argument passed is the special file name
1307          * which should not be closed.  This special file name is
1308          * in the form /dev/fd/X.
1309          */
1310         if (argc >= 3)
1311                 if (sscanf(argv[2], "/dev/fd/%d", &script_fd) != 1)
1312                         script_fd = -1;
1313                 else
1314                         /* Make sure to close this file on exec.  */
1315                         fcntl(script_fd, F_SETFD, 1);
1316
1317         if (fdinuse == NULL) {
1318                 nbytesused = sizeof (int) *
1319                     howmany(NoFile, sizeof (int) * NBBY);
1320                 fdinuse = (int *)xalloc(nbytesused);
1321         }
1322
1323         /*
1324          * Close all files except 0/1/2 to get a clean
1325          * file descritor space.
1326          */
1327         if (!is_reinit)
1328                 (void) fdwalk(close_except, &script_fd);
1329         else
1330                 (void) fdwalk(close_inuse, &script_fd);
1331
1332         didfds = 0;                     /* 0, 1, 2 aren't set up */
1333
1334         if (fstat(0, &buf) < 0)
1335                 open("/dev/null", O_RDONLY);
1336
1337         (void) fcntl(SHIN = dcopy(0, FSHIN), F_SETFD,  1);
1338         (void) fcntl(SHOUT = dcopy(1, FSHOUT), F_SETFD,  1);
1339         (void) fcntl(SHDIAG = dcopy(2, FSHDIAG), F_SETFD,  1);
1340         (void) fcntl(OLDSTD = dcopy(SHIN, FOLDSTD), F_SETFD,  1);
1341
1342         /*
1343          * Open 0/1/2 to avoid Nis+ functions to pick them up.
1344          *      Now, 0/1/2 are saved, close them and open them.
1345          */
1346         close(0); close(1); close(2);
1347         open("/dev/null", O_RDONLY);
1348         dup(0);
1349         dup(0);
1350
1351         /*
1352          * Clear fd_set mask
1353          */
1354         if (!is_reinit)
1355                 CSH_FD_ZERO(fdinuse, nbytesused);
1356 }
1357
1358 /*
1359  * This routine is called after an error to close up
1360  * any units which may have been left open accidentally.
1361  *
1362  * You only need to remove files in fdinuse list.
1363  * After you have removed the files, you can clear the
1364  * list and max_fd.
1365  */
1366 void
1367 closem(void)
1368 {
1369         int f;
1370
1371         for (f = 3; f <= max_fd; f++) {
1372                 if (CSH_FD_ISSET(f, fdinuse) &&
1373                     f != SHIN && f != SHOUT && f != SHDIAG &&
1374                     f != OLDSTD && f != FSHTTY)
1375                         close(f);
1376         }
1377         CSH_FD_ZERO(fdinuse, nbytesused);
1378         max_fd = 0;
1379 }
1380
1381 /*
1382  * Reset my_pid when a new process is created.  Only call this
1383  * if you want the process to affect fdinuse (e.g., fork, but
1384  * not vfork).
1385  */
1386 void
1387 new_process(void)
1388 {
1389         my_pid = getpid();
1390 }
1391
1392
1393 /*
1394  * Whenever Csh open/create/dup/pipe a file or files,
1395  * Csh keeps track of its open files. The open files
1396  * are kept in "fdinuse, Fd In Use" list.
1397  *
1398  * When a file descriptor is newly allocated, setfd() is
1399  * used to mark the fact in "fdinuse" list.
1400  *      For example,
1401  *              fd = open("newfile", O_RDONLY);
1402  *              setfd(fd);
1403  *
1404  * When a file is freed by close() function, unsetfd() is
1405  * used to remove the fd from "fdinuse" list.
1406  *      For example,
1407  *              close(fd);
1408  *              unsetfd(fd);
1409  */
1410 void
1411 setfd(int fd)
1412 {
1413         /*
1414          * Because you want to avoid
1415          * conflict due to vfork().
1416          */
1417         if (my_pid != getpid())
1418                 return;
1419
1420         if (fd >= NoFile || fd < 0)
1421                 return;
1422
1423         if (fd > max_fd)
1424                 max_fd = fd;
1425         CSH_FD_SET(fd, fdinuse);
1426 }
1427
1428 void
1429 unsetfd(int fd)
1430 {
1431         int i;
1432
1433         /*
1434          * Because you want to avoid
1435          * conflict due to vfork().
1436          */
1437         if (my_pid != getpid())
1438                 return;
1439
1440         if (fd >= NoFile || fd < 0)
1441                 return;
1442
1443         CSH_FD_CLR(fd, fdinuse);
1444         if (fd == max_fd) {
1445                 for (i = max_fd-1; i >= 3; i--)
1446                         if (CSH_FD_ISSET(i, fdinuse)) {
1447                                 max_fd = i;
1448                                 return;
1449                         }
1450                 max_fd = 0;
1451         }
1452 }