src/eval.c

   1 /*      $OpenBSD: eval.c,v 1.40 2013/09/14 20:09:30 millert Exp $       */
   2
   3 /*-
   4  * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   5  *               2011, 2012, 2013, 2014, 2015, 2016
   6  *      mirabilos <m@mirbsd.org>
   7  *
   8  * Provided that these terms and disclaimer and all copyright notices
   9  * are retained or reproduced in an accompanying document, permission
  10  * is granted to deal in this work without restriction, including un-
  11  * limited rights to use, publicly perform, distribute, sell, modify,
  12  * merge, give away, or sublicence.
  13  *
  14  * This work is provided "AS IS" and WITHOUT WARRANTY of any kind, to
  15  * the utmost extent permitted by applicable law, neither express nor
  16  * implied; without malicious intent or gross negligence. In no event
  17  * may a licensor, author or contributor be held liable for indirect,
  18  * direct, other damage, loss, or other issues arising in any way out
  19  * of dealing in the work, even if advised of the possibility of such
  20  * damage or existence of a defect, except proven that it results out
  21  * of said person's immediate fault when using the work as intended.
  22  */
  23
  24 #include "sh.h"
  25
  26 __RCSID("$MirOS: src/bin/mksh/eval.c,v 1.180 2016/01/19 23:12:12 tg Exp $");
  27
  28 /*
  29  * string expansion
  30  *
  31  * first pass: quoting, IFS separation, ~, ${}, $() and $(()) substitution.
  32  * second pass: alternation ({,}), filename expansion (*?[]).
  33  */
  34
  35 /* expansion generator state */
  36 typedef struct {
  37         /* not including an "int type;" member, see expand() */
  38         /* string */
  39         const char *str;
  40         /* source */
  41         union {
  42                 /* string[] */
  43                 const char **strv;
  44                 /* file */
  45                 struct shf *shf;
  46         } u;
  47         /* variable in ${var...} */
  48         struct tbl *var;
  49         /* split "$@" / call waitlast in $() */
  50         bool split;
  51 } Expand;
  52
  53 #define XBASE           0       /* scanning original */
  54 #define XSUB            1       /* expanding ${} string */
  55 #define XARGSEP         2       /* ifs0 between "$*" */
  56 #define XARG            3       /* expanding $*, $@ */
  57 #define XCOM            4       /* expanding $() */
  58 #define XNULLSUB        5       /* "$@" when $# is 0 (don't generate word) */
  59 #define XSUBMID         6       /* middle of expanding ${} */
  60
  61 /* States used for field splitting */
  62 #define IFS_WORD        0       /* word has chars (or quotes except "$@") */
  63 #define IFS_WS          1       /* have seen IFS white-space */
  64 #define IFS_NWS         2       /* have seen IFS non-white-space */
  65 #define IFS_IWS         3       /* begin of word, ignore IFS WS */
  66 #define IFS_QUOTE       4       /* beg.w/quote, become IFS_WORD unless "$@" */
  67
  68 static int varsub(Expand *, const char *, const char *, int *, int *);
  69 static int comsub(Expand *, const char *, int);
  70 static char *valsub(struct op *, Area *);
  71 static char *trimsub(char *, char *, int);
  72 static void glob(char *, XPtrV *, bool);
  73 static void globit(XString *, char **, char *, XPtrV *, int);
  74 static const char *maybe_expand_tilde(const char *, XString *, char **, bool);
  75 #ifndef MKSH_NOPWNAM
  76 static char *homedir(char *);
  77 #endif
  78 static void alt_expand(XPtrV *, char *, char *, char *, int);
  79 static int utflen(const char *) MKSH_A_PURE;
  80 static void utfincptr(const char *, mksh_ari_t *);
  81
  82 /* UTFMODE functions */
  83 static int
  84 utflen(const char *s)
  85 {
  86         size_t n;
  87
  88         if (UTFMODE) {
  89                 n = 0;
  90                 while (*s) {
  91                         s += utf_ptradj(s);
  92                         ++n;
  93                 }
  94         } else
  95                 n = strlen(s);
  96
  97         if (n > 2147483647)
  98                 n = 2147483647;
  99         return ((int)n);
 100 }
 101
 102 static void
 103 utfincptr(const char *s, mksh_ari_t *lp)
 104 {
 105         const char *cp = s;
 106
 107         while ((*lp)--)
 108                 cp += utf_ptradj(cp);
 109         *lp = cp - s;
 110 }
 111
 112 /* compile and expand word */
 113 char *
 114 substitute(const char *cp, int f)
 115 {
 116         struct source *s, *sold;
 117
 118         sold = source;
 119         s = pushs(SWSTR, ATEMP);
 120         s->start = s->str = cp;
 121         source = s;
 122         if (yylex(ONEWORD) != LWORD)
 123                 internal_errorf("bad substitution");
 124         source = sold;
 125         afree(s, ATEMP);
 126         return (evalstr(yylval.cp, f));
 127 }
 128
 129 /*
 130  * expand arg-list
 131  */
 132 char **
 133 eval(const char **ap, int f)
 134 {
 135         XPtrV w;
 136
 137         if (*ap == NULL) {
 138                 union mksh_ccphack vap;
 139
 140                 vap.ro = ap;
 141                 return (vap.rw);
 142         }
 143         XPinit(w, 32);
 144         /* space for shell name */
 145         XPput(w, NULL);
 146         while (*ap != NULL)
 147                 expand(*ap++, &w, f);
 148         XPput(w, NULL);
 149         return ((char **)XPclose(w) + 1);
 150 }
 151
 152 /*
 153  * expand string
 154  */
 155 char *
 156 evalstr(const char *cp, int f)
 157 {
 158         XPtrV w;
 159         char *dp = null;
 160
 161         XPinit(w, 1);
 162         expand(cp, &w, f);
 163         if (XPsize(w))
 164                 dp = *XPptrv(w);
 165         XPfree(w);
 166         return (dp);
 167 }
 168
 169 /*
 170  * expand string - return only one component
 171  * used from iosetup to expand redirection files
 172  */
 173 char *
 174 evalonestr(const char *cp, int f)
 175 {
 176         XPtrV w;
 177         char *rv;
 178
 179         XPinit(w, 1);
 180         expand(cp, &w, f);
 181         switch (XPsize(w)) {
 182         case 0:
 183                 rv = null;
 184                 break;
 185         case 1:
 186                 rv = (char *) *XPptrv(w);
 187                 break;
 188         default:
 189                 rv = evalstr(cp, f&~DOGLOB);
 190                 break;
 191         }
 192         XPfree(w);
 193         return (rv);
 194 }
 195
 196 /* for nested substitution: ${var:=$var2} */
 197 typedef struct SubType {
 198         struct tbl *var;        /* variable for ${var..} */
 199         struct SubType *prev;   /* old type */
 200         struct SubType *next;   /* poped type (to avoid re-allocating) */
 201         size_t  base;           /* begin position of expanded word */
 202         short   stype;          /* [=+-?%#] action after expanded word */
 203         short   f;              /* saved value of f (DOPAT, etc) */
 204         uint8_t quotep;         /* saved value of quote (for ${..[%#]..}) */
 205         uint8_t quotew;         /* saved value of quote (for ${..[+-=]..}) */
 206 } SubType;
 207
 208 void
 209 expand(
 210     /* input word */
 211     const char *ccp,
 212     /* output words */
 213     XPtrV *wp,
 214     /* DO* flags */
 215     int f)
 216 {
 217         int c = 0;
 218         /* expansion type */
 219         int type;
 220         /* quoted */
 221         int quote = 0;
 222         /* destination string and live pointer */
 223         XString ds;
 224         char *dp;
 225         /* source */
 226         const char *sp;
 227         /* second pass flags */
 228         int fdo;
 229         /* have word */
 230         int word;
 231         /* field splitting of parameter/command substitution */
 232         int doblank;
 233         /* expansion variables */
 234         Expand x = {
 235                 NULL, { NULL }, NULL, 0
 236         };
 237         SubType st_head, *st;
 238         /* record number of trailing newlines in COMSUB */
 239         int newlines = 0;
 240         bool saw_eq, make_magic;
 241         unsigned int tilde_ok;
 242         size_t len;
 243         char *cp;
 244
 245         if (ccp == NULL)
 246                 internal_errorf("expand(NULL)");
 247         /* for alias, readonly, set, typeset commands */
 248         if ((f & DOVACHECK) && is_wdvarassign(ccp)) {
 249                 f &= ~(DOVACHECK | DOBLANK | DOGLOB | DOTILDE);
 250                 f |= DOASNTILDE | DOSCALAR;
 251         }
 252         if (Flag(FNOGLOB))
 253                 f &= ~DOGLOB;
 254         if (Flag(FMARKDIRS))
 255                 f |= DOMARKDIRS;
 256         if (Flag(FBRACEEXPAND) && (f & DOGLOB))
 257                 f |= DOBRACE;
 258
 259         /* init destination string */
 260         Xinit(ds, dp, 128, ATEMP);
 261         type = XBASE;
 262         sp = ccp;
 263         fdo = 0;
 264         saw_eq = false;
 265         /* must be 1/0 */
 266         tilde_ok = (f & (DOTILDE | DOASNTILDE)) ? 1 : 0;
 267         doblank = 0;
 268         make_magic = false;
 269         word = (f&DOBLANK) ? IFS_WS : IFS_WORD;
 270         /* clang doesn't know OSUBST comes before CSUBST */
 271         memset(&st_head, 0, sizeof(st_head));
 272         st = &st_head;
 273
 274         while (/* CONSTCOND */ 1) {
 275                 Xcheck(ds, dp);
 276
 277                 switch (type) {
 278                 case XBASE:
 279                         /* original prefixed string */
 280                         c = *sp++;
 281                         switch (c) {
 282                         case EOS:
 283                                 c = 0;
 284                                 break;
 285                         case CHAR:
 286                                 c = *sp++;
 287                                 break;
 288                         case QCHAR:
 289                                 /* temporary quote */
 290                                 quote |= 2;
 291                                 c = *sp++;
 292                                 break;
 293                         case OQUOTE:
 294                                 if (word != IFS_WORD)
 295                                         word = IFS_QUOTE;
 296                                 tilde_ok = 0;
 297                                 quote = 1;
 298                                 continue;
 299                         case CQUOTE:
 300                                 if (word == IFS_QUOTE)
 301                                         word = IFS_WORD;
 302                                 quote = st->quotew;
 303                                 continue;
 304                         case COMSUB:
 305                         case FUNSUB:
 306                         case VALSUB:
 307                                 tilde_ok = 0;
 308                                 if (f & DONTRUNCOMMAND) {
 309                                         word = IFS_WORD;
 310                                         *dp++ = '$';
 311                                         *dp++ = c == COMSUB ? '(' : '{';
 312                                         if (c != COMSUB)
 313                                                 *dp++ = c == FUNSUB ? ' ' : '|';
 314                                         while (*sp != '\0') {
 315                                                 Xcheck(ds, dp);
 316                                                 *dp++ = *sp++;
 317                                         }
 318                                         if (c != COMSUB) {
 319                                                 *dp++ = ';';
 320                                                 *dp++ = '}';
 321                                         } else
 322                                                 *dp++ = ')';
 323                                 } else {
 324                                         type = comsub(&x, sp, c);
 325                                         if (type != XBASE && (f & DOBLANK))
 326                                                 doblank++;
 327                                         sp = strnul(sp) + 1;
 328                                         newlines = 0;
 329                                 }
 330                                 continue;
 331                         case EXPRSUB:
 332                                 tilde_ok = 0;
 333                                 if (f & DONTRUNCOMMAND) {
 334                                         word = IFS_WORD;
 335                                         *dp++ = '$'; *dp++ = '('; *dp++ = '(';
 336                                         while (*sp != '\0') {
 337                                                 Xcheck(ds, dp);
 338                                                 *dp++ = *sp++;
 339                                         }
 340                                         *dp++ = ')'; *dp++ = ')';
 341                                 } else {
 342                                         struct tbl v;
 343
 344                                         v.flag = DEFINED|ISSET|INTEGER;
 345                                         /* not default */
 346                                         v.type = 10;
 347                                         v.name[0] = '\0';
 348                                         v_evaluate(&v, substitute(sp, 0),
 349                                             KSH_UNWIND_ERROR, true);
 350                                         sp = strnul(sp) + 1;
 351                                         x.str = str_val(&v);
 352                                         type = XSUB;
 353                                         if (f & DOBLANK)
 354                                                 doblank++;
 355                                 }
 356                                 continue;
 357                         case OSUBST: {
 358                                 /* ${{#}var{:}[=+-?#%]word} */
 359                         /*-
 360                          * format is:
 361                          *      OSUBST [{x] plain-variable-part \0
 362                          *          compiled-word-part CSUBST [}x]
 363                          * This is where all syntax checking gets done...
 364                          */
 365                                 /* skip the { or x (}) */
 366                                 const char *varname = ++sp;
 367                                 int stype;
 368                                 int slen = 0;
 369
 370                                 /* skip variable */
 371                                 sp = cstrchr(sp, '\0') + 1;
 372                                 type = varsub(&x, varname, sp, &stype, &slen);
 373                                 if (type < 0) {
 374                                         char *beg, *end, *str;
 375  unwind_substsyn:
 376                                         /* restore sp */
 377                                         sp = varname - 2;
 378                                         end = (beg = wdcopy(sp, ATEMP)) +
 379                                             (wdscan(sp, CSUBST) - sp);
 380                                         /* ({) the } or x is already skipped */
 381                                         if (end < wdscan(beg, EOS))
 382                                                 *end = EOS;
 383                                         str = snptreef(NULL, 64, "%S", beg);
 384                                         afree(beg, ATEMP);
 385                                         errorf("%s: %s", str, "bad substitution");
 386                                 }
 387                                 if (f & DOBLANK)
 388                                         doblank++;
 389                                 tilde_ok = 0;
 390                                 if (word == IFS_QUOTE && type != XNULLSUB)
 391                                         word = IFS_WORD;
 392                                 if (type == XBASE) {
 393                                         /* expand? */
 394                                         if (!st->next) {
 395                                                 SubType *newst;
 396
 397                                                 newst = alloc(sizeof(SubType), ATEMP);
 398                                                 newst->next = NULL;
 399                                                 newst->prev = st;
 400                                                 st->next = newst;
 401                                         }
 402                                         st = st->next;
 403                                         st->stype = stype;
 404                                         st->base = Xsavepos(ds, dp);
 405                                         st->f = f;
 406                                         if (x.var == &vtemp) {
 407                                                 st->var = tempvar();
 408                                                 st->var->flag &= ~INTEGER;
 409                                                 /* can't fail here */
 410                                                 setstr(st->var,
 411                                                     str_val(x.var),
 412                                                     KSH_RETURN_ERROR | 0x4);
 413                                         } else
 414                                                 st->var = x.var;
 415
 416                                         st->quotew = st->quotep = quote;
 417                                         /* skip qualifier(s) */
 418                                         if (stype)
 419                                                 sp += slen;
 420                                         switch (stype & 0x17F) {
 421                                         case 0x100 | '#':
 422                                                 x.str = shf_smprintf("%08X",
 423                                                     (unsigned int)hash(str_val(st->var)));
 424                                                 break;
 425                                         case 0x100 | 'Q': {
 426                                                 struct shf shf;
 427
 428                                                 shf_sopen(NULL, 0, SHF_WR|SHF_DYNAMIC, &shf);
 429                                                 print_value_quoted(&shf, str_val(st->var));
 430                                                 x.str = shf_sclose(&shf);
 431                                                 break;
 432                                             }
 433                                         case '0': {
 434                                                 char *beg, *mid, *end, *stg;
 435                                                 mksh_ari_t from = 0, num = -1, flen, finc = 0;
 436
 437                                                 beg = wdcopy(sp, ATEMP);
 438                                                 mid = beg + (wdscan(sp, ADELIM) - sp);
 439                                                 stg = beg + (wdscan(sp, CSUBST) - sp);
 440                                                 mid[-2] = EOS;
 441                                                 if (mid[-1] == /*{*/'}') {
 442                                                         sp += mid - beg - 1;
 443                                                         end = NULL;
 444                                                 } else {
 445                                                         end = mid +
 446                                                             (wdscan(mid, ADELIM) - mid);
 447                                                         if (end[-1] != /*{*/ '}')
 448                                                                 /* more than max delimiters */
 449                                                                 goto unwind_substsyn;
 450                                                         end[-2] = EOS;
 451                                                         sp += end - beg - 1;
 452                                                 }
 453                                                 evaluate(substitute(stg = wdstrip(beg, 0), 0),
 454                                                     &from, KSH_UNWIND_ERROR, true);
 455                                                 afree(stg, ATEMP);
 456                                                 if (end) {
 457                                                         evaluate(substitute(stg = wdstrip(mid, 0), 0),
 458                                                             &num, KSH_UNWIND_ERROR, true);
 459                                                         afree(stg, ATEMP);
 460                                                 }
 461                                                 afree(beg, ATEMP);
 462                                                 beg = str_val(st->var);
 463                                                 flen = utflen(beg);
 464                                                 if (from < 0) {
 465                                                         if (-from < flen)
 466                                                                 finc = flen + from;
 467                                                 } else
 468                                                         finc = from < flen ? from : flen;
 469                                                 if (UTFMODE)
 470                                                         utfincptr(beg, &finc);
 471                                                 beg += finc;
 472                                                 flen = utflen(beg);
 473                                                 if (num < 0 || num > flen)
 474                                                         num = flen;
 475                                                 if (UTFMODE)
 476                                                         utfincptr(beg, &num);
 477                                                 strndupx(x.str, beg, num, ATEMP);
 478                                                 goto do_CSUBST;
 479                                             }
 480                                         case '/': {
 481                                                 char *s, *p, *d, *sbeg, *end;
 482                                                 char *pat, *rrep;
 483                                                 char fpat = 0, *tpat1, *tpat2;
 484
 485                                                 s = wdcopy(sp, ATEMP);
 486                                                 p = s + (wdscan(sp, ADELIM) - sp);
 487                                                 d = s + (wdscan(sp, CSUBST) - sp);
 488                                                 p[-2] = EOS;
 489                                                 if (p[-1] == /*{*/'}')
 490                                                         d = NULL;
 491                                                 else
 492                                                         d[-2] = EOS;
 493                                                 sp += (d ? d : p) - s - 1;
 494                                                 if (!(stype & 0x80) &&
 495                                                     s[0] == CHAR &&
 496                                                     (s[1] == '#' || s[1] == '%'))
 497                                                         fpat = s[1];
 498                                                 pat = evalstr(s + (fpat ? 2 : 0),
 499                                                     DOTILDE | DOSCALAR | DOPAT);
 500                                                 rrep = d ? evalstr(p,
 501                                                     DOTILDE | DOSCALAR) : null;
 502                                                 afree(s, ATEMP);
 503
 504                                                 /* check for special cases */
 505                                                 if (!*pat && !fpat) {
 506                                                         /*
 507                                                          * empty unanchored
 508                                                          * pattern => reject
 509                                                          */
 510                                                         goto no_repl;
 511                                                 }
 512                                                 if ((stype & 0x80) &&
 513                                                     gmatchx(null, pat, false)) {
 514                                                         /*
 515                                                          * pattern matches empty
 516                                                          * string => don't loop
 517                                                          */
 518                                                         stype &= ~0x80;
 519                                                 }
 520
 521                                                 /* prepare string on which to work */
 522                                                 strdupx(s, str_val(st->var), ATEMP);
 523                                                 sbeg = s;
 524
 525                                                 /* first see if we have any match at all */
 526                                                 if (fpat == '#') {
 527                                                         /* anchor at the beginning */
 528                                                         tpat1 = shf_smprintf("%s%c*", pat, MAGIC);
 529                                                         tpat2 = tpat1;
 530                                                 } else if (fpat == '%') {
 531                                                         /* anchor at the end */
 532                                                         tpat1 = shf_smprintf("%c*%s", MAGIC, pat);
 533                                                         tpat2 = pat;
 534                                                 } else {
 535                                                         /* float */
 536                                                         tpat1 = shf_smprintf("%c*%s%c*", MAGIC, pat, MAGIC);
 537                                                         tpat2 = tpat1 + 2;
 538                                                 }
 539  again_repl:
 540                                                 /*
 541                                                  * this would not be necessary if gmatchx would return
 542                                                  * the start and end values of a match found, like re*
 543                                                  */
 544                                                 if (!gmatchx(sbeg, tpat1, false))
 545                                                         goto end_repl;
 546                                                 end = strnul(s);
 547                                                 /* now anchor the beginning of the match */
 548                                                 if (fpat != '#')
 549                                                         while (sbeg <= end) {
 550                                                                 if (gmatchx(sbeg, tpat2, false))
 551                                                                         break;
 552                                                                 else
 553                                                                         sbeg++;
 554                                                         }
 555                                                 /* now anchor the end of the match */
 556                                                 p = end;
 557                                                 if (fpat != '%')
 558                                                         while (p >= sbeg) {
 559                                                                 bool gotmatch;
 560
 561                                                                 c = *p;
 562                                                                 *p = '\0';
 563                                                                 gotmatch = tobool(gmatchx(sbeg, pat, false));
 564                                                                 *p = c;
 565                                                                 if (gotmatch)
 566                                                                         break;
 567                                                                 p--;
 568                                                         }
 569                                                 strndupx(end, s, sbeg - s, ATEMP);
 570                                                 d = shf_smprintf("%s%s%s", end, rrep, p);
 571                                                 afree(end, ATEMP);
 572                                                 sbeg = d + (sbeg - s) + strlen(rrep);
 573                                                 afree(s, ATEMP);
 574                                                 s = d;
 575                                                 if (stype & 0x80)
 576                                                         goto again_repl;
 577  end_repl:
 578                                                 afree(tpat1, ATEMP);
 579                                                 x.str = s;
 580  no_repl:
 581                                                 afree(pat, ATEMP);
 582                                                 if (rrep != null)
 583                                                         afree(rrep, ATEMP);
 584                                                 goto do_CSUBST;
 585                                             }
 586                                         case '#':
 587                                         case '%':
 588                                                 /* ! DOBLANK,DOBRACE */
 589                                                 f = (f & DONTRUNCOMMAND) |
 590                                                     DOPAT | DOTILDE |
 591                                                     DOTEMP | DOSCALAR;
 592                                                 tilde_ok = 1;
 593                                                 st->quotew = quote = 0;
 594                                                 /*
 595                                                  * Prepend open pattern (so |
 596                                                  * in a trim will work as
 597                                                  * expected)
 598                                                  */
 599                                                 if (!Flag(FSH)) {
 600                                                         *dp++ = MAGIC;
 601                                                         *dp++ = 0x80 | '@';
 602                                                 }
 603                                                 break;
 604                                         case '=':
 605                                                 /*
 606                                                  * Enabling tilde expansion
 607                                                  * after :s here is
 608                                                  * non-standard ksh, but is
 609                                                  * consistent with rules for
 610                                                  * other assignments. Not
 611                                                  * sure what POSIX thinks of
 612                                                  * this.
 613                                                  * Not doing tilde expansion
 614                                                  * for integer variables is a
 615                                                  * non-POSIX thing - makes
 616                                                  * sense though, since ~ is
 617                                                  * a arithmetic operator.
 618                                                  */
 619                                                 if (!(x.var->flag & INTEGER))
 620                                                         f |= DOASNTILDE | DOTILDE;
 621                                                 f |= DOTEMP;
 622                                                 /*
 623                                                  * These will be done after the
 624                                                  * value has been assigned.
 625                                                  */
 626                                                 f &= ~(DOBLANK|DOGLOB|DOBRACE);
 627                                                 tilde_ok = 1;
 628                                                 break;
 629                                         case '?':
 630                                                 if (*sp == CSUBST)
 631                                                         errorf("%s: parameter null or not set",
 632                                                             st->var->name);
 633                                                 f &= ~DOBLANK;
 634                                                 f |= DOTEMP;
 635                                                 /* FALLTHROUGH */
 636                                         default:
 637                                                 /* '-' '+' '?' */
 638                                                 if (quote)
 639                                                         word = IFS_WORD;
 640                                                 else if (dp == Xstring(ds, dp))
 641                                                         word = IFS_IWS;
 642                                                 /* Enable tilde expansion */
 643                                                 tilde_ok = 1;
 644                                                 f |= DOTILDE;
 645                                         }
 646                                 } else
 647                                         /* skip word */
 648                                         sp += wdscan(sp, CSUBST) - sp;
 649                                 continue;
 650                             }
 651                         case CSUBST:
 652                                 /* only get here if expanding word */
 653  do_CSUBST:
 654                                 /* ({) skip the } or x */
 655                                 sp++;
 656                                 /* in case of ${unset:-} */
 657                                 tilde_ok = 0;
 658                                 *dp = '\0';
 659                                 quote = st->quotep;
 660                                 f = st->f;
 661                                 if (f & DOBLANK)
 662                                         doblank--;
 663                                 switch (st->stype & 0x17F) {
 664                                 case '#':
 665                                 case '%':
 666                                         if (!Flag(FSH)) {
 667                                                 /* Append end-pattern */
 668                                                 *dp++ = MAGIC;
 669                                                 *dp++ = ')';
 670                                         }
 671                                         *dp = '\0';
 672                                         dp = Xrestpos(ds, dp, st->base);
 673                                         /*
 674                                          * Must use st->var since calling
 675                                          * global would break things
 676                                          * like x[i+=1].
 677                                          */
 678                                         x.str = trimsub(str_val(st->var),
 679                                                 dp, st->stype);
 680                                         if (x.str[0] != '\0') {
 681                                                 word = IFS_IWS;
 682                                                 type = XSUB;
 683                                         } else if (quote) {
 684                                                 word = IFS_WORD;
 685                                                 type = XSUB;
 686                                         } else {
 687                                                 if (dp == Xstring(ds, dp))
 688                                                         word = IFS_IWS;
 689                                                 type = XNULLSUB;
 690                                         }
 691                                         if (f & DOBLANK)
 692                                                 doblank++;
 693                                         st = st->prev;
 694                                         continue;
 695                                 case '=':
 696                                         /*
 697                                          * Restore our position and substitute
 698                                          * the value of st->var (may not be
 699                                          * the assigned value in the presence
 700                                          * of integer/right-adj/etc attributes).
 701                                          */
 702                                         dp = Xrestpos(ds, dp, st->base);
 703                                         /*
 704                                          * Must use st->var since calling
 705                                          * global would cause with things
 706                                          * like x[i+=1] to be evaluated twice.
 707                                          */
 708                                         /*
 709                                          * Note: not exported by FEXPORT
 710                                          * in AT&T ksh.
 711                                          */
 712                                         /*
 713                                          * XXX POSIX says readonly is only
 714                                          * fatal for special builtins (setstr
 715                                          * does readonly check).
 716                                          */
 717                                         len = strlen(dp) + 1;
 718                                         setstr(st->var,
 719                                             debunk(alloc(len, ATEMP),
 720                                             dp, len), KSH_UNWIND_ERROR);
 721                                         x.str = str_val(st->var);
 722                                         type = XSUB;
 723                                         if (f & DOBLANK)
 724                                                 doblank++;
 725                                         st = st->prev;
 726                                         word = quote || (!*x.str && (f & DOSCALAR)) ? IFS_WORD : IFS_IWS;
 727                                         continue;
 728                                 case '?':
 729                                         dp = Xrestpos(ds, dp, st->base);
 730
 731                                         errorf("%s: %s", st->var->name,
 732                                             debunk(dp, dp, strlen(dp) + 1));
 733                                         break;
 734                                 case '0':
 735                                 case '/':
 736                                 case 0x100 | '#':
 737                                 case 0x100 | 'Q':
 738                                         dp = Xrestpos(ds, dp, st->base);
 739                                         type = XSUB;
 740                                         word = quote || (!*x.str && (f & DOSCALAR)) ? IFS_WORD : IFS_IWS;
 741                                         if (f & DOBLANK)
 742                                                 doblank++;
 743                                         st = st->prev;
 744                                         continue;
 745                                 /* default: '-' '+' */
 746                                 }
 747                                 st = st->prev;
 748                                 type = XBASE;
 749                                 continue;
 750
 751                         case OPAT:
 752                                 /* open pattern: *(foo|bar) */
 753                                 /* Next char is the type of pattern */
 754                                 make_magic = true;
 755                                 c = *sp++ | 0x80;
 756                                 break;
 757
 758                         case SPAT:
 759                                 /* pattern separator (|) */
 760                                 make_magic = true;
 761                                 c = '|';
 762                                 break;
 763
 764                         case CPAT:
 765                                 /* close pattern */
 766                                 make_magic = true;
 767                                 c = /*(*/ ')';
 768                                 break;
 769                         }
 770                         break;
 771
 772                 case XNULLSUB:
 773                         /*
 774                          * Special case for "$@" (and "${foo[@]}") - no
 775                          * word is generated if $# is 0 (unless there is
 776                          * other stuff inside the quotes).
 777                          */
 778                         type = XBASE;
 779                         if (f & DOBLANK) {
 780                                 doblank--;
 781                                 if (dp == Xstring(ds, dp) && word != IFS_WORD)
 782                                         word = IFS_IWS;
 783                         }
 784                         continue;
 785
 786                 case XSUB:
 787                 case XSUBMID:
 788                         if ((c = *x.str++) == 0) {
 789                                 type = XBASE;
 790                                 if (f & DOBLANK)
 791                                         doblank--;
 792                                 continue;
 793                         }
 794                         break;
 795
 796                 case XARGSEP:
 797                         type = XARG;
 798                         quote = 1;
 799                         /* FALLTHROUGH */
 800                 case XARG:
 801                         if ((c = *x.str++) == '\0') {
 802                                 /*
 803                                  * force null words to be created so
 804                                  * set -- "" 2 ""; echo "$@" will do
 805                                  * the right thing
 806                                  */
 807                                 if (quote && x.split)
 808                                         word = IFS_WORD;
 809                                 if ((x.str = *x.u.strv++) == NULL) {
 810                                         type = XBASE;
 811                                         if (f & DOBLANK)
 812                                                 doblank--;
 813                                         continue;
 814                                 }
 815                                 c = ifs0;
 816                                 if ((f & DOHEREDOC)) {
 817                                         /* pseudo-field-split reliably */
 818                                         if (c == 0)
 819                                                 c = ' ';
 820                                         break;
 821                                 }
 822                                 if ((f & DOSCALAR)) {
 823                                         /* do not field-split */
 824                                         if (x.split) {
 825                                                 c = ' ';
 826                                                 break;
 827                                         }
 828                                         if (c == 0)
 829                                                 continue;
 830                                 }
 831                                 if (c == 0) {
 832                                         if (quote && !x.split)
 833                                                 continue;
 834                                         if (!quote && word == IFS_WS)
 835                                                 continue;
 836                                         /* this is so we don't terminate */
 837                                         c = ' ';
 838                                         /* now force-emit a word */
 839                                         goto emit_word;
 840                                 }
 841                                 if (quote && x.split) {
 842                                         /* terminate word for "$@" */
 843                                         type = XARGSEP;
 844                                         quote = 0;
 845                                 }
 846                         }
 847                         break;
 848
 849                 case XCOM:
 850                         if (x.u.shf == NULL) {
 851                                 /* $(<...) failed */
 852                                 subst_exstat = 1;
 853                                 /* fake EOF */
 854                                 c = -1;
 855                         } else if (newlines) {
 856                                 /* spit out saved NLs */
 857                                 c = '\n';
 858                                 --newlines;
 859                         } else {
 860                                 while ((c = shf_getc(x.u.shf)) == 0 || c == '\n')
 861                                         if (c == '\n')
 862                                                 /* save newlines */
 863                                                 newlines++;
 864                                 if (newlines && c != -1) {
 865                                         shf_ungetc(c, x.u.shf);
 866                                         c = '\n';
 867                                         --newlines;
 868                                 }
 869                         }
 870                         if (c == -1) {
 871                                 newlines = 0;
 872                                 if (x.u.shf)
 873                                         shf_close(x.u.shf);
 874                                 if (x.split)
 875                                         subst_exstat = waitlast();
 876                                 type = XBASE;
 877                                 if (f & DOBLANK)
 878                                         doblank--;
 879                                 continue;
 880                         }
 881                         break;
 882                 }
 883
 884                 /* check for end of word or IFS separation */
 885                 if (c == 0 || (!quote && (f & DOBLANK) && doblank &&
 886                     !make_magic && ctype(c, C_IFS))) {
 887                         /*-
 888                          * How words are broken up:
 889                          *                      |       value of c
 890                          *      word            |       ws      nws     0
 891                          *      -----------------------------------
 892                          *      IFS_WORD                w/WS    w/NWS   w
 893                          *      IFS_WS                  -/WS    -/NWS   -
 894                          *      IFS_NWS                 -/NWS   w/NWS   -
 895                          *      IFS_IWS                 -/WS    w/NWS   -
 896                          * (w means generate a word)
 897                          */
 898                         if ((word == IFS_WORD) || (word == IFS_QUOTE) || (c &&
 899                             (word == IFS_IWS || word == IFS_NWS) &&
 900                             !ctype(c, C_IFSWS))) {
 901  emit_word:
 902                                 if (f & DOHERESTR)
 903                                         *dp++ = '\n';
 904                                 *dp++ = '\0';
 905                                 cp = Xclose(ds, dp);
 906                                 if (fdo & DOBRACE)
 907                                         /* also does globbing */
 908                                         alt_expand(wp, cp, cp,
 909                                             cp + Xlength(ds, (dp - 1)),
 910                                             fdo | (f & DOMARKDIRS));
 911                                 else if (fdo & DOGLOB)
 912                                         glob(cp, wp, tobool(f & DOMARKDIRS));
 913                                 else if ((f & DOPAT) || !(fdo & DOMAGIC))
 914                                         XPput(*wp, cp);
 915                                 else
 916                                         XPput(*wp, debunk(cp, cp,
 917                                             strlen(cp) + 1));
 918                                 fdo = 0;
 919                                 saw_eq = false;
 920                                 /* must be 1/0 */
 921                                 tilde_ok = (f & (DOTILDE | DOASNTILDE)) ? 1 : 0;
 922                                 if (c == 0)
 923                                         return;
 924                                 Xinit(ds, dp, 128, ATEMP);
 925                         } else if (c == 0) {
 926                                 return;
 927                         } else if (type == XSUB && ctype(c, C_IFS) &&
 928                             !ctype(c, C_IFSWS) && Xlength(ds, dp) == 0) {
 929                                 *(cp = alloc(1, ATEMP)) = '\0';
 930                                 XPput(*wp, cp);
 931                                 type = XSUBMID;
 932                         }
 933                         if (word != IFS_NWS)
 934                                 word = ctype(c, C_IFSWS) ? IFS_WS : IFS_NWS;
 935                 } else {
 936                         if (type == XSUB) {
 937                                 if (word == IFS_NWS &&
 938                                     Xlength(ds, dp) == 0) {
 939                                         *(cp = alloc(1, ATEMP)) = '\0';
 940                                         XPput(*wp, cp);
 941                                 }
 942                                 type = XSUBMID;
 943                         }
 944
 945                         /* age tilde_ok info - ~ code tests second bit */
 946                         tilde_ok <<= 1;
 947                         /* mark any special second pass chars */
 948                         if (!quote)
 949                                 switch (c) {
 950                                 case '[':
 951                                 case '!':
 952                                 case '-':
 953                                 case ']':
 954                                         /*
 955                                          * For character classes - doesn't hurt
 956                                          * to have magic !,-,]s outside of
 957                                          * [...] expressions.
 958                                          */
 959                                         if (f & (DOPAT | DOGLOB)) {
 960                                                 fdo |= DOMAGIC;
 961                                                 if (c == '[')
 962                                                         fdo |= f & DOGLOB;
 963                                                 *dp++ = MAGIC;
 964                                         }
 965                                         break;
 966                                 case '*':
 967                                 case '?':
 968                                         if (f & (DOPAT | DOGLOB)) {
 969                                                 fdo |= DOMAGIC | (f & DOGLOB);
 970                                                 *dp++ = MAGIC;
 971                                         }
 972                                         break;
 973                                 case '{':
 974                                 case '}':
 975                                 case ',':
 976                                         if ((f & DOBRACE) && (c == '{' /*}*/ ||
 977                                             (fdo & DOBRACE))) {
 978                                                 fdo |= DOBRACE|DOMAGIC;
 979                                                 *dp++ = MAGIC;
 980                                         }
 981                                         break;
 982                                 case '=':
 983                                         /* Note first unquoted = for ~ */
 984                                         if (!(f & DOTEMP) && (!Flag(FPOSIX) ||
 985                                             (f & DOASNTILDE)) && !saw_eq) {
 986                                                 saw_eq = true;
 987                                                 tilde_ok = 1;
 988                                         }
 989                                         break;
 990                                 case ':':
 991                                         /* : */
 992                                         /* Note unquoted : for ~ */
 993                                         if (!(f & DOTEMP) && (f & DOASNTILDE))
 994                                                 tilde_ok = 1;
 995                                         break;
 996                                 case '~':
 997                                         /*
 998                                          * tilde_ok is reset whenever
 999                                          * any of ' " $( $(( ${ } are seen.
1000                                          * Note that tilde_ok must be preserved
1001                                          * through the sequence ${A=a=}~
1002                                          */
1003                                         if (type == XBASE &&
1004                                             (f & (DOTILDE | DOASNTILDE)) &&
1005                                             (tilde_ok & 2)) {
1006                                                 const char *tcp;
1007                                                 char *tdp = dp;
1008
1009                                                 tcp = maybe_expand_tilde(sp,
1010                                                     &ds, &tdp,
1011                                                     tobool(f & DOASNTILDE));
1012                                                 if (tcp) {
1013                                                         if (dp != tdp)
1014                                                                 word = IFS_WORD;
1015                                                         dp = tdp;
1016                                                         sp = tcp;
1017                                                         continue;
1018                                                 }
1019                                         }
1020                                         break;
1021                                 }
1022                         else
1023                                 /* undo temporary */
1024                                 quote &= ~2;
1025
1026                         if (make_magic) {
1027                                 make_magic = false;
1028                                 fdo |= DOMAGIC | (f & DOGLOB);
1029                                 *dp++ = MAGIC;
1030                         } else if (ISMAGIC(c)) {
1031                                 fdo |= DOMAGIC;
1032                                 *dp++ = MAGIC;
1033                         }
1034                         /* save output char */
1035                         *dp++ = c;
1036                         word = IFS_WORD;
1037                 }
1038         }
1039 }
1040
1041 static bool
1042 hasnonempty(const char **strv)
1043 {
1044         size_t i = 0;
1045
1046         while (strv[i])
1047                 if (*strv[i++])
1048                         return (true);
1049         return (false);
1050 }
1051
1052 /*
1053  * Prepare to generate the string returned by ${} substitution.
1054  */
1055 static int
1056 varsub(Expand *xp, const char *sp, const char *word,
1057     int *stypep,        /* becomes qualifier type */
1058     int *slenp)         /* " " len (=, :=, etc.) valid iff *stypep != 0 */
1059 {
1060         int c;
1061         int state;      /* next state: XBASE, XARG, XSUB, XNULLSUB */
1062         int stype;      /* substitution type */
1063         int slen;
1064         const char *p;
1065         struct tbl *vp;
1066         bool zero_ok = false;
1067
1068         if ((stype = sp[0]) == '\0')
1069                 /* Bad variable name */
1070                 return (-1);
1071
1072         xp->var = NULL;
1073
1074         /*-
1075          * ${#var}, string length (-U: characters, +U: octets) or array size
1076          * ${%var}, string width (-U: screen columns, +U: octets)
1077          */
1078         c = sp[1];
1079         if (stype == '%' && c == '\0')
1080                 return (-1);
1081         if ((stype == '#' || stype == '%') && c != '\0') {
1082                 /* Can't have any modifiers for ${#...} or ${%...} */
1083                 if (*word != CSUBST)
1084                         return (-1);
1085                 sp++;
1086                 /* Check for size of array */
1087                 if ((p = cstrchr(sp, '[')) && (p[1] == '*' || p[1] == '@') &&
1088                     p[2] == ']') {
1089                         int n = 0;
1090
1091                         if (stype != '#')
1092                                 return (-1);
1093                         vp = global(arrayname(sp));
1094                         if (vp->flag & (ISSET|ARRAY))
1095                                 zero_ok = true;
1096                         for (; vp; vp = vp->u.array)
1097                                 if (vp->flag & ISSET)
1098                                         n++;
1099                         c = n;
1100                 } else if (c == '*' || c == '@') {
1101                         if (stype != '#')
1102                                 return (-1);
1103                         c = e->loc->argc;
1104                 } else {
1105                         p = str_val(global(sp));
1106                         zero_ok = p != null;
1107                         if (stype == '#')
1108                                 c = utflen(p);
1109                         else {
1110                                 /* partial utf_mbswidth reimplementation */
1111                                 const char *s = p;
1112                                 unsigned int wc;
1113                                 size_t len;
1114                                 int cw;
1115
1116                                 c = 0;
1117                                 while (*s) {
1118                                         if (!UTFMODE || (len = utf_mbtowc(&wc,
1119                                             s)) == (size_t)-1)
1120                                                 /* not UTFMODE or not UTF-8 */
1121                                                 wc = (unsigned char)(*s++);
1122                                         else
1123                                                 /* UTFMODE and UTF-8 */
1124                                                 s += len;
1125                                         /* wc == char or wchar at s++ */
1126                                         if ((cw = utf_wcwidth(wc)) == -1) {
1127                                                 /* 646, 8859-1, 10646 C0/C1 */
1128                                                 c = -1;
1129                                                 break;
1130                                         }
1131                                         c += cw;
1132                                 }
1133                         }
1134                 }
1135                 if (Flag(FNOUNSET) && c == 0 && !zero_ok)
1136                         errorf("%s: %s", sp, "parameter not set");
1137                 /* unqualified variable/string substitution */
1138                 *stypep = 0;
1139                 xp->str = shf_smprintf("%d", c);
1140                 return (XSUB);
1141         }
1142
1143         /* Check for qualifiers in word part */
1144         stype = 0;
1145         c = word[slen = 0] == CHAR ? word[1] : 0;
1146         if (c == ':') {
1147                 slen += 2;
1148                 stype = 0x80;
1149                 c = word[slen + 0] == CHAR ? word[slen + 1] : 0;
1150         }
1151         if (!stype && c == '/') {
1152                 slen += 2;
1153                 stype = c;
1154                 if (word[slen] == ADELIM) {
1155                         slen += 2;
1156                         stype |= 0x80;
1157                 }
1158         } else if (stype == 0x80 && (c == ' ' || c == '0')) {
1159                 stype |= '0';
1160         } else if (ctype(c, C_SUBOP1)) {
1161                 slen += 2;
1162                 stype |= c;
1163         } else if (ctype(c, C_SUBOP2)) {
1164                 /* Note: ksh88 allows :%, :%%, etc */
1165                 slen += 2;
1166                 stype = c;
1167                 if (word[slen + 0] == CHAR && c == word[slen + 1]) {
1168                         stype |= 0x80;
1169                         slen += 2;
1170                 }
1171         } else if (c == '@') {
1172                 /* @x where x is command char */
1173                 slen += 2;
1174                 stype |= 0x100;
1175                 if (word[slen] == CHAR) {
1176                         stype |= word[slen + 1];
1177                         slen += 2;
1178                 }
1179         } else if (stype)
1180                 /* : is not ok */
1181                 return (-1);
1182         if (!stype && *word != CSUBST)
1183                 return (-1);
1184         *stypep = stype;
1185         *slenp = slen;
1186
1187         c = sp[0];
1188         if (c == '*' || c == '@') {
1189                 switch (stype & 0x17F) {
1190                 /* can't assign to a vector */
1191                 case '=':
1192                 /* can't trim a vector (yet) */
1193                 case '%':
1194                 case '#':
1195                 case '0':
1196                 case '/':
1197                 case 0x100 | '#':
1198                 case 0x100 | 'Q':
1199                         return (-1);
1200                 }
1201                 if (e->loc->argc == 0) {
1202                         xp->str = null;
1203                         xp->var = global(sp);
1204                         state = c == '@' ? XNULLSUB : XSUB;
1205                 } else {
1206                         xp->u.strv = (const char **)e->loc->argv + 1;
1207                         xp->str = *xp->u.strv++;
1208                         /* $@ */
1209                         xp->split = tobool(c == '@');
1210                         state = XARG;
1211                 }
1212                 /* POSIX 2009? */
1213                 zero_ok = true;
1214         } else {
1215                 if ((p = cstrchr(sp, '[')) && (p[1] == '*' || p[1] == '@') &&
1216                     p[2] == ']') {
1217                         XPtrV wv;
1218
1219                         switch (stype & 0x17F) {
1220                         /* can't assign to a vector */
1221                         case '=':
1222                         /* can't trim a vector (yet) */
1223                         case '%':
1224                         case '#':
1225                         case '?':
1226                         case '0':
1227                         case '/':
1228                         case 0x100 | '#':
1229                         case 0x100 | 'Q':
1230                                 return (-1);
1231                         }
1232                         XPinit(wv, 32);
1233                         if ((c = sp[0]) == '!')
1234                                 ++sp;
1235                         vp = global(arrayname(sp));
1236                         for (; vp; vp = vp->u.array) {
1237                                 if (!(vp->flag&ISSET))
1238                                         continue;
1239                                 XPput(wv, c == '!' ? shf_smprintf("%lu",
1240                                     arrayindex(vp)) :
1241                                     str_val(vp));
1242                         }
1243                         if (XPsize(wv) == 0) {
1244                                 xp->str = null;
1245                                 state = p[1] == '@' ? XNULLSUB : XSUB;
1246                                 XPfree(wv);
1247                         } else {
1248                                 XPput(wv, 0);
1249                                 xp->u.strv = (const char **)XPptrv(wv);
1250                                 xp->str = *xp->u.strv++;
1251                                 /* ${foo[@]} */
1252                                 xp->split = tobool(p[1] == '@');
1253                                 state = XARG;
1254                         }
1255                 } else {
1256                         /* Can't assign things like $! or $1 */
1257                         if ((stype & 0x17F) == '=' &&
1258                             ctype(*sp, C_VAR1 | C_DIGIT))
1259                                 return (-1);
1260                         if (*sp == '!' && sp[1]) {
1261                                 ++sp;
1262                                 xp->var = global(sp);
1263                                 if (vstrchr(sp, '['))
1264                                         xp->str = shf_smprintf("%s[%lu]",
1265                                             xp->var->name,
1266                                             arrayindex(xp->var));
1267                                 else
1268                                         xp->str = xp->var->name;
1269                         } else {
1270                                 xp->var = global(sp);
1271                                 xp->str = str_val(xp->var);
1272                         }
1273                         state = XSUB;
1274                 }
1275         }
1276
1277         c = stype & 0x7F;
1278         /* test the compiler's code generator */
1279         if (((stype < 0x100) && (ctype(c, C_SUBOP2) || c == '/' ||
1280             (((stype & 0x80) ? *xp->str == '\0' : xp->str == null) &&
1281             (state != XARG || (ifs0 || xp->split ?
1282             (xp->u.strv[0] == NULL) : !hasnonempty(xp->u.strv))) ?
1283             c == '=' || c == '-' || c == '?' : c == '+'))) ||
1284             stype == (0x80 | '0') || stype == (0x100 | '#') ||
1285             stype == (0x100 | 'Q'))
1286                 /* expand word instead of variable value */
1287                 state = XBASE;
1288         if (Flag(FNOUNSET) && xp->str == null && !zero_ok &&
1289             (ctype(c, C_SUBOP2) || (state != XBASE && c != '+')))
1290                 errorf("%s: %s", sp, "parameter not set");
1291         return (state);
1292 }
1293
1294 /*
1295  * Run the command in $(...) and read its output.
1296  */
1297 static int
1298 comsub(Expand *xp, const char *cp, int fn MKSH_A_UNUSED)
1299 {
1300         Source *s, *sold;
1301         struct op *t;
1302         struct shf *shf;
1303         uint8_t old_utfmode = UTFMODE;
1304
1305         s = pushs(SSTRING, ATEMP);
1306         s->start = s->str = cp;
1307         sold = source;
1308         t = compile(s, true);
1309         afree(s, ATEMP);
1310         source = sold;
1311
1312         UTFMODE = old_utfmode;
1313
1314         if (t == NULL)
1315                 return (XBASE);
1316
1317         /* no waitlast() unless specifically enabled later */
1318         xp->split = false;
1319
1320         if (t->type == TCOM &&
1321             *t->args == NULL && *t->vars == NULL && t->ioact != NULL) {
1322                 /* $(<file) */
1323                 struct ioword *io = *t->ioact;
1324                 char *name;
1325
1326                 if ((io->ioflag & IOTYPE) != IOREAD)
1327                         errorf("%s: %s", T_funny_command,
1328                             snptreef(NULL, 32, "%R", io));
1329                 shf = shf_open(name = evalstr(io->ioname, DOTILDE), O_RDONLY,
1330                         0, SHF_MAPHI | SHF_CLEXEC);
1331                 if (shf == NULL)
1332                         warningf(!Flag(FTALKING), "%s: %s %s: %s", name,
1333                             "can't open", "$(<...) input", cstrerror(errno));
1334         } else if (fn == FUNSUB) {
1335                 int ofd1;
1336                 struct temp *tf = NULL;
1337
1338                 /*
1339                  * create a temporary file, open for reading and writing,
1340                  * with an shf open for reading (buffered) but yet unused
1341                  */
1342                 maketemp(ATEMP, TT_FUNSUB, &tf);
1343                 if (!tf->shf) {
1344                         errorf("can't %s temporary file %s: %s",
1345                             "create", tf->tffn, cstrerror(errno));
1346                 }
1347                 /* extract shf from temporary file, unlink and free it */
1348                 shf = tf->shf;
1349                 unlink(tf->tffn);
1350                 afree(tf, ATEMP);
1351                 /* save stdout and let it point to the tempfile */
1352                 ofd1 = savefd(1);
1353                 ksh_dup2(shf_fileno(shf), 1, false);
1354                 /*
1355                  * run tree, with output thrown into the tempfile,
1356                  * in a new function block
1357                  */
1358                 valsub(t, NULL);
1359                 subst_exstat = exstat & 0xFF;
1360                 /* rewind the tempfile and restore regular stdout */
1361                 lseek(shf_fileno(shf), (off_t)0, SEEK_SET);
1362                 restfd(1, ofd1);
1363         } else if (fn == VALSUB) {
1364                 xp->str = valsub(t, ATEMP);
1365                 subst_exstat = exstat & 0xFF;
1366                 return (XSUB);
1367         } else {
1368                 int ofd1, pv[2];
1369
1370                 openpipe(pv);
1371                 shf = shf_fdopen(pv[0], SHF_RD, NULL);
1372                 ofd1 = savefd(1);
1373                 if (pv[1] != 1) {
1374                         ksh_dup2(pv[1], 1, false);
1375                         close(pv[1]);
1376                 }
1377                 execute(t, XXCOM | XPIPEO | XFORK, NULL);
1378                 restfd(1, ofd1);
1379                 startlast();
1380                 /* waitlast() */
1381                 xp->split = true;
1382         }
1383
1384         xp->u.shf = shf;
1385         return (XCOM);
1386 }
1387
1388 /*
1389  * perform #pattern and %pattern substitution in ${}
1390  */
1391 static char *
1392 trimsub(char *str, char *pat, int how)
1393 {
1394         char *end = strnul(str);
1395         char *p, c;
1396
1397         switch (how & 0xFF) {
1398         case '#':
1399                 /* shortest match at beginning */
1400                 for (p = str; p <= end; p += utf_ptradj(p)) {
1401                         c = *p; *p = '\0';
1402                         if (gmatchx(str, pat, false)) {
1403                                 *p = c;
1404                                 return (p);
1405                         }
1406                         *p = c;
1407                 }
1408                 break;
1409         case '#'|0x80:
1410                 /* longest match at beginning */
1411                 for (p = end; p >= str; p--) {
1412                         c = *p; *p = '\0';
1413                         if (gmatchx(str, pat, false)) {
1414                                 *p = c;
1415                                 return (p);
1416                         }
1417                         *p = c;
1418                 }
1419                 break;
1420         case '%':
1421                 /* shortest match at end */
1422                 p = end;
1423                 while (p >= str) {
1424                         if (gmatchx(p, pat, false))
1425                                 goto trimsub_match;
1426                         if (UTFMODE) {
1427                                 char *op = p;
1428                                 while ((p-- > str) && ((*p & 0xC0) == 0x80))
1429                                         ;
1430                                 if ((p < str) || (p + utf_ptradj(p) != op))
1431                                         p = op - 1;
1432                         } else
1433                                 --p;
1434                 }
1435                 break;
1436         case '%'|0x80:
1437                 /* longest match at end */
1438                 for (p = str; p <= end; p++)
1439                         if (gmatchx(p, pat, false)) {
1440  trimsub_match:
1441                                 strndupx(end, str, p - str, ATEMP);
1442                                 return (end);
1443                         }
1444                 break;
1445         }
1446
1447         /* no match, return string */
1448         return (str);
1449 }
1450
1451 /*
1452  * glob
1453  * Name derived from V6's /etc/glob, the program that expanded filenames.
1454  */
1455
1456 /* XXX cp not const 'cause slashes are temporarily replaced with NULs... */
1457 static void
1458 glob(char *cp, XPtrV *wp, bool markdirs)
1459 {
1460         int oldsize = XPsize(*wp);
1461
1462         if (glob_str(cp, wp, markdirs) == 0)
1463                 XPput(*wp, debunk(cp, cp, strlen(cp) + 1));
1464         else
1465                 qsort(XPptrv(*wp) + oldsize, XPsize(*wp) - oldsize,
1466                     sizeof(void *), xstrcmp);
1467 }
1468
1469 #define GF_NONE         0
1470 #define GF_EXCHECK      BIT(0)          /* do existence check on file */
1471 #define GF_GLOBBED      BIT(1)          /* some globbing has been done */
1472 #define GF_MARKDIR      BIT(2)          /* add trailing / to directories */
1473
1474 /*
1475  * Apply file globbing to cp and store the matching files in wp. Returns
1476  * the number of matches found.
1477  */
1478 int
1479 glob_str(char *cp, XPtrV *wp, bool markdirs)
1480 {
1481         int oldsize = XPsize(*wp);
1482         XString xs;
1483         char *xp;
1484
1485         Xinit(xs, xp, 256, ATEMP);
1486         globit(&xs, &xp, cp, wp, markdirs ? GF_MARKDIR : GF_NONE);
1487         Xfree(xs, xp);
1488
1489         return (XPsize(*wp) - oldsize);
1490 }
1491
1492 static void
1493 globit(XString *xs,     /* dest string */
1494     char **xpp,         /* ptr to dest end */
1495     char *sp,           /* source path */
1496     XPtrV *wp,          /* output list */
1497     int check)          /* GF_* flags */
1498 {
1499         char *np;               /* next source component */
1500         char *xp = *xpp;
1501         char *se;
1502         char odirsep;
1503
1504         /* This to allow long expansions to be interrupted */
1505         intrcheck();
1506
1507         if (sp == NULL) {
1508                 /* end of source path */
1509                 /*
1510                  * We only need to check if the file exists if a pattern
1511                  * is followed by a non-pattern (eg, foo*x/bar; no check
1512                  * is needed for foo* since the match must exist) or if
1513                  * any patterns were expanded and the markdirs option is set.
1514                  * Symlinks make things a bit tricky...
1515                  */
1516                 if ((check & GF_EXCHECK) ||
1517                     ((check & GF_MARKDIR) && (check & GF_GLOBBED))) {
1518 #define stat_check()    (stat_done ? stat_done : (stat_done = \
1519                             stat(Xstring(*xs, xp), &statb) < 0 ? -1 : 1))
1520                         struct stat lstatb, statb;
1521                         /* -1: failed, 1 ok, 0 not yet done */
1522                         int stat_done = 0;
1523
1524                         if (mksh_lstat(Xstring(*xs, xp), &lstatb) < 0)
1525                                 return;
1526                         /*
1527                          * special case for systems which strip trailing
1528                          * slashes from regular files (eg, /etc/passwd/).
1529                          * SunOS 4.1.3 does this...
1530                          */
1531                         if ((check & GF_EXCHECK) && xp > Xstring(*xs, xp) &&
1532                             xp[-1] == '/' && !S_ISDIR(lstatb.st_mode) &&
1533                             (!S_ISLNK(lstatb.st_mode) ||
1534                             stat_check() < 0 || !S_ISDIR(statb.st_mode)))
1535                                 return;
1536                         /*
1537                          * Possibly tack on a trailing / if there isn't already
1538                          * one and if the file is a directory or a symlink to a
1539                          * directory
1540                          */
1541                         if (((check & GF_MARKDIR) && (check & GF_GLOBBED)) &&
1542                             xp > Xstring(*xs, xp) && xp[-1] != '/' &&
1543                             (S_ISDIR(lstatb.st_mode) ||
1544                             (S_ISLNK(lstatb.st_mode) && stat_check() > 0 &&
1545                             S_ISDIR(statb.st_mode)))) {
1546                                 *xp++ = '/';
1547                                 *xp = '\0';
1548                         }
1549                 }
1550                 strndupx(np, Xstring(*xs, xp), Xlength(*xs, xp), ATEMP);
1551                 XPput(*wp, np);
1552                 return;
1553         }
1554
1555         if (xp > Xstring(*xs, xp))
1556                 *xp++ = '/';
1557         while (*sp == '/') {
1558                 Xcheck(*xs, xp);
1559                 *xp++ = *sp++;
1560         }
1561         np = strchr(sp, '/');
1562         if (np != NULL) {
1563                 se = np;
1564                 /* don't assume '/', can be multiple kinds */
1565                 odirsep = *np;
1566                 *np++ = '\0';
1567         } else {
1568                 odirsep = '\0'; /* keep gcc quiet */
1569                 se = sp + strlen(sp);
1570         }
1571
1572
1573         /*
1574          * Check if sp needs globbing - done to avoid pattern checks for strings
1575          * containing MAGIC characters, open [s without the matching close ],
1576          * etc. (otherwise opendir() will be called which may fail because the
1577          * directory isn't readable - if no globbing is needed, only execute
1578          * permission should be required (as per POSIX)).
1579          */
1580         if (!has_globbing(sp, se)) {
1581                 XcheckN(*xs, xp, se - sp + 1);
1582                 debunk(xp, sp, Xnleft(*xs, xp));
1583                 xp += strlen(xp);
1584                 *xpp = xp;
1585                 globit(xs, xpp, np, wp, check);
1586         } else {
1587                 DIR *dirp;
1588                 struct dirent *d;
1589                 char *name;
1590                 size_t len, prefix_len;
1591
1592                 /* xp = *xpp;   copy_non_glob() may have re-alloc'd xs */
1593                 *xp = '\0';
1594                 prefix_len = Xlength(*xs, xp);
1595                 dirp = opendir(prefix_len ? Xstring(*xs, xp) : ".");
1596                 if (dirp == NULL)
1597                         goto Nodir;
1598                 while ((d = readdir(dirp)) != NULL) {
1599                         name = d->d_name;
1600                         if (name[0] == '.' &&
1601                             (name[1] == 0 || (name[1] == '.' && name[2] == 0)))
1602                                 /* always ignore . and .. */
1603                                 continue;
1604                         if ((*name == '.' && *sp != '.') ||
1605                             !gmatchx(name, sp, true))
1606                                 continue;
1607
1608                         len = strlen(d->d_name) + 1;
1609                         XcheckN(*xs, xp, len);
1610                         memcpy(xp, name, len);
1611                         *xpp = xp + len - 1;
1612                         globit(xs, xpp, np, wp,
1613                                 (check & GF_MARKDIR) | GF_GLOBBED
1614                                 | (np ? GF_EXCHECK : GF_NONE));
1615                         xp = Xstring(*xs, xp) + prefix_len;
1616                 }
1617                 closedir(dirp);
1618  Nodir:
1619                 ;
1620         }
1621
1622         if (np != NULL)
1623                 *--np = odirsep;
1624 }
1625
1626 /* remove MAGIC from string */
1627 char *
1628 debunk(char *dp, const char *sp, size_t dlen)
1629 {
1630         char *d;
1631         const char *s;
1632
1633         if ((s = cstrchr(sp, MAGIC))) {
1634                 if (s - sp >= (ssize_t)dlen)
1635                         return (dp);
1636                 memmove(dp, sp, s - sp);
1637                 for (d = dp + (s - sp); *s && (d - dp < (ssize_t)dlen); s++)
1638                         if (!ISMAGIC(*s) || !(*++s & 0x80) ||
1639                             !vstrchr("*+?@! ", *s & 0x7f))
1640                                 *d++ = *s;
1641                         else {
1642                                 /* extended pattern operators: *+?@! */
1643                                 if ((*s & 0x7f) != ' ')
1644                                         *d++ = *s & 0x7f;
1645                                 if (d - dp < (ssize_t)dlen)
1646                                         *d++ = '(';
1647                         }
1648                 *d = '\0';
1649         } else if (dp != sp)
1650                 strlcpy(dp, sp, dlen);
1651         return (dp);
1652 }
1653
1654 /*
1655  * Check if p is an unquoted name, possibly followed by a / or :. If so
1656  * puts the expanded version in *dcp,dp and returns a pointer in p just
1657  * past the name, otherwise returns 0.
1658  */
1659 static const char *
1660 maybe_expand_tilde(const char *p, XString *dsp, char **dpp, bool isassign)
1661 {
1662         XString ts;
1663         char *dp = *dpp;
1664         char *tp;
1665         const char *r;
1666
1667         Xinit(ts, tp, 16, ATEMP);
1668         /* : only for DOASNTILDE form */
1669         while (p[0] == CHAR && p[1] != '/' && (!isassign || p[1] != ':'))
1670         {
1671                 Xcheck(ts, tp);
1672                 *tp++ = p[1];
1673                 p += 2;
1674         }
1675         *tp = '\0';
1676         r = (p[0] == EOS || p[0] == CHAR || p[0] == CSUBST) ?
1677             do_tilde(Xstring(ts, tp)) : NULL;
1678         Xfree(ts, tp);
1679         if (r) {
1680                 while (*r) {
1681                         Xcheck(*dsp, dp);
1682                         if (ISMAGIC(*r))
1683                                 *dp++ = MAGIC;
1684                         *dp++ = *r++;
1685                 }
1686                 *dpp = dp;
1687                 r = p;
1688         }
1689         return (r);
1690 }
1691
1692 /*
1693  * tilde expansion
1694  *
1695  * based on a version by Arnold Robbins
1696  */
1697
1698 char *
1699 do_tilde(char *cp)
1700 {
1701         char *dp = null;
1702
1703         if (cp[0] == '\0')
1704                 dp = str_val(global("HOME"));
1705         else if (cp[0] == '+' && cp[1] == '\0')
1706                 dp = str_val(global("PWD"));
1707         else if (ksh_isdash(cp))
1708                 dp = str_val(global("OLDPWD"));
1709 #ifndef MKSH_NOPWNAM
1710         else
1711                 dp = homedir(cp);
1712 #endif
1713         /* If HOME, PWD or OLDPWD are not set, don't expand ~ */
1714         return (dp == null ? NULL : dp);
1715 }
1716
1717 #ifndef MKSH_NOPWNAM
1718 /*
1719  * map userid to user's home directory.
1720  * note that 4.3's getpw adds more than 6K to the shell,
1721  * and the YP version probably adds much more.
1722  * we might consider our own version of getpwnam() to keep the size down.
1723  */
1724 static char *
1725 homedir(char *name)
1726 {
1727         struct tbl *ap;
1728
1729         ap = ktenter(&homedirs, name, hash(name));
1730         if (!(ap->flag & ISSET)) {
1731                 struct passwd *pw;
1732
1733                 pw = getpwnam(name);
1734                 if (pw == NULL)
1735                         return (NULL);
1736                 strdupx(ap->val.s, pw->pw_dir, APERM);
1737                 ap->flag |= DEFINED|ISSET|ALLOC;
1738         }
1739         return (ap->val.s);
1740 }
1741 #endif
1742
1743 static void
1744 alt_expand(XPtrV *wp, char *start, char *exp_start, char *end, int fdo)
1745 {
1746         unsigned int count = 0;
1747         char *brace_start, *brace_end, *comma = NULL;
1748         char *field_start;
1749         char *p = exp_start;
1750
1751         /* search for open brace */
1752         while ((p = strchr(p, MAGIC)) && p[1] != '{' /*}*/)
1753                 p += 2;
1754         brace_start = p;
1755
1756         /* find matching close brace, if any */
1757         if (p) {
1758                 comma = NULL;
1759                 count = 1;
1760                 p += 2;
1761                 while (*p && count) {
1762                         if (ISMAGIC(*p++)) {
1763                                 if (*p == '{' /*}*/)
1764                                         ++count;
1765                                 else if (*p == /*{*/ '}')
1766                                         --count;
1767                                 else if (*p == ',' && count == 1)
1768                                         comma = p;
1769                                 ++p;
1770                         }
1771                 }
1772         }
1773         /* no valid expansions... */
1774         if (!p || count != 0) {
1775                 /*
1776                  * Note that given a{{b,c} we do not expand anything (this is
1777                  * what AT&T ksh does. This may be changed to do the {b,c}
1778                  * expansion. }
1779                  */
1780                 if (fdo & DOGLOB)
1781                         glob(start, wp, tobool(fdo & DOMARKDIRS));
1782                 else
1783                         XPput(*wp, debunk(start, start, end - start));
1784                 return;
1785         }
1786         brace_end = p;
1787         if (!comma) {
1788                 alt_expand(wp, start, brace_end, end, fdo);
1789                 return;
1790         }
1791
1792         /* expand expression */
1793         field_start = brace_start + 2;
1794         count = 1;
1795         for (p = brace_start + 2; p != brace_end; p++) {
1796                 if (ISMAGIC(*p)) {
1797                         if (*++p == '{' /*}*/)
1798                                 ++count;
1799                         else if ((*p == /*{*/ '}' && --count == 0) ||
1800                             (*p == ',' && count == 1)) {
1801                                 char *news;
1802                                 int l1, l2, l3;
1803
1804                                 /*
1805                                  * addition safe since these operate on
1806                                  * one string (separate substrings)
1807                                  */
1808                                 l1 = brace_start - start;
1809                                 l2 = (p - 1) - field_start;
1810                                 l3 = end - brace_end;
1811                                 news = alloc(l1 + l2 + l3 + 1, ATEMP);
1812                                 memcpy(news, start, l1);
1813                                 memcpy(news + l1, field_start, l2);
1814                                 memcpy(news + l1 + l2, brace_end, l3);
1815                                 news[l1 + l2 + l3] = '\0';
1816                                 alt_expand(wp, news, news + l1,
1817                                     news + l1 + l2 + l3, fdo);
1818                                 field_start = p + 1;
1819                         }
1820                 }
1821         }
1822         return;
1823 }
1824
1825 /* helper function due to setjmp/longjmp woes */
1826 static char *
1827 valsub(struct op *t, Area *ap)
1828 {
1829         char * volatile cp = NULL;
1830         struct tbl * volatile vp = NULL;
1831
1832         newenv(E_FUNC);
1833         newblock();
1834         if (ap)
1835                 vp = local("REPLY", false);
1836         if (!kshsetjmp(e->jbuf))
1837                 execute(t, XXCOM | XERROK, NULL);
1838         if (vp)
1839                 strdupx(cp, str_val(vp), ap);
1840         quitenv(NULL);
1841
1842         return (cp);
1843 }