box/coreutils/test.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * test implementation for busybox
   4  *
   5  * Copyright (c) by a whole pile of folks:
   6  *
   7  *     test(1); version 7-like  --  author Erik Baalbergen
   8  *     modified by Eric Gisin to be used as built-in.
   9  *     modified by Arnold Robbins to add SVR3 compatibility
  10  *     (-x -c -b -p -u -g -k) plus Korn's -L -nt -ot -ef and new -S (socket).
  11  *     modified by J.T. Conklin for NetBSD.
  12  *     modified by Herbert Xu to be used as built-in in ash.
  13  *     modified by Erik Andersen <andersen@codepoet.org> to be used
  14  *     in busybox.
  15  *     modified by Bernhard Fischer to be useable (i.e. a bit less bloaty).
  16  *
  17  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  18  *
  19  * Original copyright notice states:
  20  *     "This program is in the Public Domain."
  21  */
  22
  23 #include "libbb.h"
  24 #include <setjmp.h>
  25
  26 /* This is a NOEXEC applet. Be very careful! */
  27
  28
  29 /* test(1) accepts the following grammar:
  30         oexpr   ::= aexpr | aexpr "-o" oexpr ;
  31         aexpr   ::= nexpr | nexpr "-a" aexpr ;
  32         nexpr   ::= primary | "!" primary
  33         primary ::= unary-operator operand
  34                 | operand binary-operator operand
  35                 | operand
  36                 | "(" oexpr ")"
  37                 ;
  38         unary-operator ::= "-r"|"-w"|"-x"|"-f"|"-d"|"-c"|"-b"|"-p"|
  39                 "-u"|"-g"|"-k"|"-s"|"-t"|"-z"|"-n"|"-o"|"-O"|"-G"|"-L"|"-S";
  40
  41         binary-operator ::= "="|"=="|"!="|"-eq"|"-ne"|"-ge"|"-gt"|"-le"|"-lt"|
  42                         "-nt"|"-ot"|"-ef";
  43         operand ::= <any legal UNIX file name>
  44 */
  45
  46 enum token {
  47         EOI,
  48         FILRD,
  49         FILWR,
  50         FILEX,
  51         FILEXIST,
  52         FILREG,
  53         FILDIR,
  54         FILCDEV,
  55         FILBDEV,
  56         FILFIFO,
  57         FILSOCK,
  58         FILSYM,
  59         FILGZ,
  60         FILTT,
  61         FILSUID,
  62         FILSGID,
  63         FILSTCK,
  64         FILNT,
  65         FILOT,
  66         FILEQ,
  67         FILUID,
  68         FILGID,
  69         STREZ,
  70         STRNZ,
  71         STREQ,
  72         STRNE,
  73         STRLT,
  74         STRGT,
  75         INTEQ,
  76         INTNE,
  77         INTGE,
  78         INTGT,
  79         INTLE,
  80         INTLT,
  81         UNOT,
  82         BAND,
  83         BOR,
  84         LPAREN,
  85         RPAREN,
  86         OPERAND
  87 };
  88 #define is_int_op(a) (((unsigned char)((a) - INTEQ)) <= 5)
  89 #define is_str_op(a) (((unsigned char)((a) - STREZ)) <= 5)
  90 #define is_file_op(a) (((unsigned char)((a) - FILNT)) <= 2)
  91 #define is_file_access(a) (((unsigned char)((a) - FILRD)) <= 2)
  92 #define is_file_type(a) (((unsigned char)((a) - FILREG)) <= 5)
  93 #define is_file_bit(a) (((unsigned char)((a) - FILSUID)) <= 2)
  94 enum token_types {
  95         UNOP,
  96         BINOP,
  97         BUNOP,
  98         BBINOP,
  99         PAREN
 100 };
 101
 102 static const struct t_op {
 103         char op_text[4];
 104         unsigned char op_num, op_type;
 105 } ops[] = {
 106         { "-r", FILRD   , UNOP   },
 107         { "-w", FILWR   , UNOP   },
 108         { "-x", FILEX   , UNOP   },
 109         { "-e", FILEXIST, UNOP   },
 110         { "-f", FILREG  , UNOP   },
 111         { "-d", FILDIR  , UNOP   },
 112         { "-c", FILCDEV , UNOP   },
 113         { "-b", FILBDEV , UNOP   },
 114         { "-p", FILFIFO , UNOP   },
 115         { "-u", FILSUID , UNOP   },
 116         { "-g", FILSGID , UNOP   },
 117         { "-k", FILSTCK , UNOP   },
 118         { "-s", FILGZ   , UNOP   },
 119         { "-t", FILTT   , UNOP   },
 120         { "-z", STREZ   , UNOP   },
 121         { "-n", STRNZ   , UNOP   },
 122         { "-h", FILSYM  , UNOP   },    /* for backwards compat */
 123
 124         { "-O" , FILUID , UNOP   },
 125         { "-G" , FILGID , UNOP   },
 126         { "-L" , FILSYM , UNOP   },
 127         { "-S" , FILSOCK, UNOP   },
 128         { "="  , STREQ  , BINOP  },
 129         { "==" , STREQ  , BINOP  },
 130         { "!=" , STRNE  , BINOP  },
 131         { "<"  , STRLT  , BINOP  },
 132         { ">"  , STRGT  , BINOP  },
 133         { "-eq", INTEQ  , BINOP  },
 134         { "-ne", INTNE  , BINOP  },
 135         { "-ge", INTGE  , BINOP  },
 136         { "-gt", INTGT  , BINOP  },
 137         { "-le", INTLE  , BINOP  },
 138         { "-lt", INTLT  , BINOP  },
 139         { "-nt", FILNT  , BINOP  },
 140         { "-ot", FILOT  , BINOP  },
 141         { "-ef", FILEQ  , BINOP  },
 142         { "!"  , UNOT   , BUNOP  },
 143         { "-a" , BAND   , BBINOP },
 144         { "-o" , BOR    , BBINOP },
 145         { "("  , LPAREN , PAREN  },
 146         { ")"  , RPAREN , PAREN  },
 147 };
 148
 149 enum { NUM_OPS = sizeof(ops) / sizeof(ops[0]) };
 150
 151 #if ENABLE_FEATURE_TEST_64
 152 typedef int64_t arith_t;
 153 #else
 154 typedef int arith_t;
 155 #endif
 156
 157 /* Cannot eliminate these static data (do the G trick)
 158  * because of bb_test usage from other applets */
 159 static char **t_wp;
 160 static struct t_op const *t_wp_op;
 161 static gid_t *group_array;
 162 static int ngroups;
 163 static jmp_buf leaving;
 164
 165 static enum token t_lex(char *s);
 166 static arith_t oexpr(enum token n);
 167 static arith_t aexpr(enum token n);
 168 static arith_t nexpr(enum token n);
 169 static int binop(void);
 170 static arith_t primary(enum token n);
 171 static int filstat(char *nm, enum token mode);
 172 static arith_t getn(const char *s);
 173 /* UNUSED
 174 static int newerf(const char *f1, const char *f2);
 175 static int olderf(const char *f1, const char *f2);
 176 static int equalf(const char *f1, const char *f2);
 177 */
 178 static int test_eaccess(char *path, int mode);
 179 static int is_a_group_member(gid_t gid);
 180 static void initialize_group_array(void);
 181
 182 int bb_test(int argc, char **argv)
 183 {
 184         int res;
 185         char *arg0;
 186         bool _off;
 187
 188         arg0 = strrchr(argv[0], '/');
 189         if (!arg0++) arg0 = argv[0];
 190         if (arg0[0] == '[') {
 191                 --argc;
 192                 if (!arg0[1]) { /* "[" ? */
 193                         if (NOT_LONE_CHAR(argv[argc], ']')) {
 194                                 bb_error_msg("missing ]");
 195                                 return 2;
 196                         }
 197                 } else { /* assuming "[[" */
 198                         if (strcmp(argv[argc], "]]") != 0) {
 199                                 bb_error_msg("missing ]]");
 200                                 return 2;
 201                         }
 202                 }
 203                 argv[argc] = NULL;
 204         }
 205
 206         res = setjmp(leaving);
 207         if (res)
 208                 return res;
 209
 210         /* resetting ngroups is probably unnecessary.  it will
 211          * force a new call to getgroups(), which prevents using
 212          * group data fetched during a previous call.  but the
 213          * only way the group data could be stale is if there's
 214          * been an intervening call to setgroups(), and this
 215          * isn't likely in the case of a shell.  paranoia
 216          * prevails...
 217          */
 218         ngroups = 0;
 219
 220         /* Implement special cases from POSIX.2, section 4.62.4 */
 221         if (argc == 1)
 222                 return 1;
 223         if (argc == 2)
 224                 return *argv[1] == '\0';
 225 //assert(argc);
 226         /* remember if we saw argc==4 which wants *no* '!' test */
 227         _off = argc - 4;
 228         if (_off ?
 229                 (LONE_CHAR(argv[1], '!'))
 230                 : (argv[1][0] != '!' || argv[1][1] != '\0'))
 231         {
 232                 if (argc == 3)
 233                         return *argv[2] != '\0';
 234
 235                 t_lex(argv[2 + _off]);
 236                 if (t_wp_op && t_wp_op->op_type == BINOP) {
 237                         t_wp = &argv[1 + _off];
 238                         return binop() == _off;
 239                 }
 240         }
 241         t_wp = &argv[1];
 242         res = !oexpr(t_lex(*t_wp));
 243
 244         if (*t_wp != NULL && *++t_wp != NULL) {
 245                 bb_error_msg("%s: unknown operand", *t_wp);
 246                 return 2;
 247         }
 248         return res;
 249 }
 250
 251 static void syntax(const char *op, const char *msg) ATTRIBUTE_NORETURN;
 252 static void syntax(const char *op, const char *msg)
 253 {
 254         if (op && *op) {
 255                 bb_error_msg("%s: %s", op, msg);
 256         } else {
 257                 bb_error_msg("%s: %s"+4, msg);
 258         }
 259         longjmp(leaving, 2);
 260 }
 261
 262 static arith_t oexpr(enum token n)
 263 {
 264         arith_t res;
 265
 266         res = aexpr(n);
 267         if (t_lex(*++t_wp) == BOR) {
 268                 return oexpr(t_lex(*++t_wp)) || res;
 269         }
 270         t_wp--;
 271         return res;
 272 }
 273
 274 static arith_t aexpr(enum token n)
 275 {
 276         arith_t res;
 277
 278         res = nexpr(n);
 279         if (t_lex(*++t_wp) == BAND)
 280                 return aexpr(t_lex(*++t_wp)) && res;
 281         t_wp--;
 282         return res;
 283 }
 284
 285 static arith_t nexpr(enum token n)
 286 {
 287         if (n == UNOT)
 288                 return !nexpr(t_lex(*++t_wp));
 289         return primary(n);
 290 }
 291
 292 static arith_t primary(enum token n)
 293 {
 294         arith_t res;
 295
 296         if (n == EOI) {
 297                 syntax(NULL, "argument expected");
 298         }
 299         if (n == LPAREN) {
 300                 res = oexpr(t_lex(*++t_wp));
 301                 if (t_lex(*++t_wp) != RPAREN)
 302                         syntax(NULL, "closing paren expected");
 303                 return res;
 304         }
 305         if (t_wp_op && t_wp_op->op_type == UNOP) {
 306                 /* unary expression */
 307                 if (*++t_wp == NULL)
 308                         syntax(t_wp_op->op_text, "argument expected");
 309                 if (n == STREZ)
 310                         return t_wp[0][0] == '\0';
 311                 if (n == STRNZ)
 312                         return t_wp[0][0] != '\0';
 313                 if (n == FILTT)
 314                         return isatty(getn(*t_wp));
 315                 return filstat(*t_wp, n);
 316         }
 317
 318         t_lex(t_wp[1]);
 319         if (t_wp_op && t_wp_op->op_type == BINOP) {
 320                 return binop();
 321         }
 322
 323         return t_wp[0][0] != '\0';
 324 }
 325
 326 static int binop(void)
 327 {
 328         const char *opnd1, *opnd2;
 329         struct t_op const *op;
 330         arith_t val1, val2;
 331
 332         opnd1 = *t_wp;
 333         (void) t_lex(*++t_wp);
 334         op = t_wp_op;
 335
 336         opnd2 = *++t_wp;
 337         if (opnd2 == NULL)
 338                 syntax(op->op_text, "argument expected");
 339
 340         if (is_int_op(op->op_num)) {
 341                 val1 = getn(opnd1);
 342                 val2 = getn(opnd2);
 343                 if (op->op_num == INTEQ)
 344                         return val1 == val2;
 345                 if (op->op_num == INTNE)
 346                         return val1 != val2;
 347                 if (op->op_num == INTGE)
 348                         return val1 >= val2;
 349                 if (op->op_num == INTGT)
 350                         return val1 >  val2;
 351                 if (op->op_num == INTLE)
 352                         return val1 <= val2;
 353                 if (op->op_num == INTLT)
 354                         return val1 <  val2;
 355         }
 356         if (is_str_op(op->op_num)) {
 357                 val1 = strcmp(opnd1, opnd2);
 358                 if (op->op_num == STREQ)
 359                         return val1 == 0;
 360                 if (op->op_num == STRNE)
 361                         return val1 != 0;
 362                 if (op->op_num == STRLT)
 363                         return val1 < 0;
 364                 if (op->op_num == STRGT)
 365                         return val1 > 0;
 366         }
 367         /* We are sure that these three are by now the only binops we didn't check
 368          * yet, so we do not check if the class is correct:
 369          */
 370 /*      if (is_file_op(op->op_num)) */
 371         {
 372                 struct stat b1, b2;
 373
 374                 if (stat(opnd1, &b1) || stat(opnd2, &b2))
 375                         return 0; /* false, since at least one stat failed */
 376                 if (op->op_num == FILNT)
 377                         return b1.st_mtime > b2.st_mtime;
 378                 if (op->op_num == FILOT)
 379                         return b1.st_mtime < b2.st_mtime;
 380                 if (op->op_num == FILEQ)
 381                         return b1.st_dev == b2.st_dev && b1.st_ino == b2.st_ino;
 382         }
 383         return 1; /* NOTREACHED */
 384 }
 385
 386 static int filstat(char *nm, enum token mode)
 387 {
 388         struct stat s;
 389         int i = i; /* gcc 3.x thinks it can be used uninitialized */
 390
 391         if (mode == FILSYM) {
 392 #ifdef S_IFLNK
 393                 if (lstat(nm, &s) == 0) {
 394                         i = S_IFLNK;
 395                         goto filetype;
 396                 }
 397 #endif
 398                 return 0;
 399         }
 400
 401 #ifdef __MINGW32__
 402         if (mode == FILEX) {
 403                 int len = strlen(nm), ret;
 404                 char *exepath;
 405                 if (len >= 4 && !strcmp(nm+len-4,".exe"))
 406                         exepath = nm;
 407                 else {
 408                         exepath = malloc(len+5);
 409                         memcpy(exepath, nm, len);
 410                         memcpy(exepath+len, ".exe", 5);
 411                 }
 412                 ret = stat(exepath, &s);
 413                 if (exepath != nm)
 414                         free(exepath);
 415                 return ret >= 0;
 416         }
 417 #endif
 418
 419         if (stat(nm, &s) != 0)
 420                 return 0;
 421         if (mode == FILEXIST)
 422                 return 1;
 423         if (is_file_access(mode)) {
 424                 if (mode == FILRD)
 425                         i = R_OK;
 426                 if (mode == FILWR)
 427                         i = W_OK;
 428                 if (mode == FILEX)
 429                         i = X_OK;
 430                 return test_eaccess(nm, i) == 0;
 431         }
 432         if (is_file_type(mode)) {
 433                 if (mode == FILREG)
 434                         i = S_IFREG;
 435                 if (mode == FILDIR)
 436                         i = S_IFDIR;
 437                 if (mode == FILCDEV)
 438                         i = S_IFCHR;
 439                 if (mode == FILBDEV)
 440                         i = S_IFBLK;
 441                 if (mode == FILFIFO) {
 442 #ifdef S_IFIFO
 443                         i = S_IFIFO;
 444 #else
 445                         return 0;
 446 #endif
 447                 }
 448                 if (mode == FILSOCK) {
 449 #ifdef S_IFSOCK
 450                         i = S_IFSOCK;
 451 #else
 452                         return 0;
 453 #endif
 454                 }
 455  filetype:
 456                 return ((s.st_mode & S_IFMT) == i);
 457         }
 458         if (is_file_bit(mode)) {
 459                 if (mode == FILSUID)
 460                         i = S_ISUID;
 461                 if (mode == FILSGID)
 462                         i = S_ISGID;
 463                 if (mode == FILSTCK)
 464                         i = S_ISVTX;
 465                 return ((s.st_mode & i) != 0);
 466         }
 467         if (mode == FILGZ)
 468                 return s.st_size > 0L;
 469 #ifndef __MINGW32__
 470         if (mode == FILUID)
 471                 return s.st_uid == geteuid();
 472         if (mode == FILGID)
 473                 return s.st_gid == getegid();
 474 #endif
 475         return 1; /* NOTREACHED */
 476 }
 477
 478 static enum token t_lex(char *s)
 479 {
 480         const struct t_op *op;
 481
 482         t_wp_op = NULL;
 483         if (s == NULL) {
 484                 return EOI;
 485         }
 486
 487         op = ops;
 488         do {
 489                 if (strcmp(s, op->op_text) == 0) {
 490                         t_wp_op = op;
 491                         return op->op_num;
 492                 }
 493                 op++;
 494         } while (op < ops + NUM_OPS);
 495
 496         return OPERAND;
 497 }
 498
 499 /* atoi with error detection */
 500 //XXX: FIXME: duplicate of existing libbb function?
 501 static arith_t getn(const char *s)
 502 {
 503         char *p;
 504 #if ENABLE_FEATURE_TEST_64
 505         long long r;
 506 #else
 507         long r;
 508 #endif
 509
 510         errno = 0;
 511 #if ENABLE_FEATURE_TEST_64
 512         r = strtoll(s, &p, 10);
 513 #else
 514         r = strtol(s, &p, 10);
 515 #endif
 516
 517         if (errno != 0)
 518                 syntax(s, "out of range");
 519
 520         if (*(skip_whitespace(p)))
 521                 syntax(s, "bad number");
 522
 523         return r;
 524 }
 525
 526 /* UNUSED
 527 static int newerf(const char *f1, const char *f2)
 528 {
 529         struct stat b1, b2;
 530
 531         return (stat(f1, &b1) == 0 &&
 532                         stat(f2, &b2) == 0 && b1.st_mtime > b2.st_mtime);
 533 }
 534
 535 static int olderf(const char *f1, const char *f2)
 536 {
 537         struct stat b1, b2;
 538
 539         return (stat(f1, &b1) == 0 &&
 540                         stat(f2, &b2) == 0 && b1.st_mtime < b2.st_mtime);
 541 }
 542
 543 static int equalf(const char *f1, const char *f2)
 544 {
 545         struct stat b1, b2;
 546
 547         return (stat(f1, &b1) == 0 &&
 548                         stat(f2, &b2) == 0 &&
 549                         b1.st_dev == b2.st_dev && b1.st_ino == b2.st_ino);
 550 }
 551 */
 552
 553 /* Do the same thing access(2) does, but use the effective uid and gid,
 554    and don't make the mistake of telling root that any file is
 555    executable. */
 556 static int test_eaccess(char *path, int mode)
 557 {
 558         struct stat st;
 559 #ifndef __MINGW32__
 560         unsigned int euid = geteuid();
 561 #endif
 562
 563         if (stat(path, &st) < 0)
 564                 return -1;
 565
 566 #ifndef __MINGW32__
 567         if (euid == 0) {
 568                 /* Root can read or write any file. */
 569                 if (mode != X_OK)
 570                         return 0;
 571
 572                 /* Root can execute any file that has any one of the execute
 573                    bits set. */
 574                 if (st.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH))
 575                         return 0;
 576         }
 577
 578         if (st.st_uid == euid)  /* owner */
 579                 mode <<= 6;
 580         else if (is_a_group_member(st.st_gid))
 581                 mode <<= 3;
 582 #endif
 583
 584         if (st.st_mode & mode)
 585                 return 0;
 586
 587         return -1;
 588 }
 589
 590 #ifndef __MINGW32__
 591 static void initialize_group_array(void)
 592 {
 593         ngroups = getgroups(0, NULL);
 594         if (ngroups > 0) {
 595                 /* FIXME: ash tries so hard to not die on OOM,
 596                  * and we spoil it with just one xrealloc here */
 597                 /* We realloc, because bb_test can be entered repeatedly by shell.
 598                  * Testcase (ash): 'while true; do test -x some_file; done'
 599                  * and watch top. (some_file must have owner != you) */
 600                 group_array = xrealloc(group_array, ngroups * sizeof(gid_t));
 601                 getgroups(ngroups, group_array);
 602         }
 603 }
 604
 605 /* Return non-zero if GID is one that we have in our groups list. */
 606 //XXX: FIXME: duplicate of existing libbb function?
 607 // see toplevel TODO file:
 608 // possible code duplication ingroup() and is_a_group_member()
 609 static int is_a_group_member(gid_t gid)
 610 {
 611         int i;
 612
 613         /* Short-circuit if possible, maybe saving a call to getgroups(). */
 614         if (gid == getgid() || gid == getegid())
 615                 return 1;
 616
 617         if (ngroups == 0)
 618                 initialize_group_array();
 619
 620         /* Search through the list looking for GID. */
 621         for (i = 0; i < ngroups; i++)
 622                 if (gid == group_array[i])
 623                         return 1;
 624
 625         return 0;
 626 }
 627 #endif
 628
 629
 630 /* applet entry point */
 631
 632 int test_main(int argc, char **argv);
 633 int test_main(int argc, char **argv)
 634 {
 635         return bb_test(argc, argv);
 636 }