LXR toybox/toys/posix/test.c

   1/* test.c - evaluate expression
   2 *
   3 * Copyright 2018 Rob Landley <rob@landley.net>
   4 *
   5 * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/test.html
   6
   7USE_TEST(NEWTOY(test, 0, TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_NOHELP))
   8
   9config TEST
  10  bool "test"
  11  default y
  12  help
  13    usage: test [-bcdefghLPrSsuwx PATH] [-nz STRING] [-t FD] [X ?? Y]
  14
  15    Return true or false by performing tests. (With no arguments return false.)
  16
  17    --- Tests with a single argument (after the option):
  18    PATH is/has:
  19      -b  block device   -f  regular file   -p  fifo           -u  setuid bit
  20      -c  char device    -g  setgid         -r  read bit       -w  write bit
  21      -d  directory      -h  symlink        -S  socket         -x  execute bit
  22      -e  exists         -L  symlink        -s  nonzero size
  23    STRING is:
  24      -n  nonzero size   -z  zero size      (STRING by itself implies -n)
  25    FD (integer file descriptor) is:
  26      -t  a TTY
  27
  28    --- Tests with one argument on each side of an operator:
  29    Two strings:
  30      =  are identical   !=  differ
  31    Two integers:
  32      -eq  equal         -gt  first > second    -lt  first < second
  33      -ne  not equal     -ge  first >= second   -le  first <= second
  34
  35    --- Modify or combine tests:
  36      ! EXPR     not (swap true/false)   EXPR -a EXPR    and (are both true)
  37      ( EXPR )   evaluate this first     EXPR -o EXPR    or (is either true)
  38*/
  39
  40#include "toys.h"
  41
  42// Consume 3, 2, or 1 argument test, returning result and *count used.
  43int do_test(char **args, int *count)
  44{
  45  char c, *s;
  46  int i;
  47
  48  if (*count>=3) {
  49    *count = 3;
  50    char *s = args[1], *ss = "eqnegtgeltle";
  51    if (!strcmp(s, "=") || !strcmp(s, "==")) return !strcmp(args[0], args[2]);
  52    if (!strcmp(s, "!=")) return strcmp(args[0], args[2]);
  53    if (*s=='-' && strlen(s)==3 && (s = strstr(ss, s+1)) && !((i = s-ss)&1)) {
  54      long long a = atolx(args[0]), b = atolx(args[2]);
  55
  56      if (!i) return a == b;
  57      if (i==2) return a != b;
  58      if (i==4) return a > b;
  59      if (i==6) return a >= b;
  60      if (i==8) return a < b;
  61      if (i==10) return a<= b;
  62    }
  63  }
  64  s = *args;
  65  if (*count>=2 && *s == '-' && s[1] && !s[2]) {
  66    *count = 2;
  67    c = s[1];
  68    if (-1 != (i = stridx("hLbcdefgpSusxwr", c))) {
  69      struct stat st;
  70
  71      // stat or lstat, then handle rwx and s
  72      if (-1 == ((i<2) ? lstat : stat)(args[1], &st)) return 0;
  73      if (i>=12) return !!(st.st_mode&(0x111<<(i-12)));
  74      if (c == 's') return !!st.st_size; // otherwise 1<<32 == 0
  75
  76      // handle file type checking and SUID/SGID
  77      if ((i = (unsigned short []){80,80,48,16,32,0,64,2,8,96,4}[i]<<9)>=4096)
  78        return (st.st_mode&S_IFMT) == i;
  79      else return (st.st_mode & i) == i;
  80    } else if (c == 'z') return !*args[1];
  81    else if (c == 'n') return *args[1];
  82    else if (c == 't') return isatty(atolx(args[1]));
  83  }
  84  return *count = 0;
  85}
  86
  87#define NOT 1  // Most recent test had an odd number of preceding !
  88#define AND 2  // test before -a failed since -o or ( so force false
  89#define OR  4  // test before -o succeeded since ( so force true
  90void test_main(void)
  91{
  92  char *s;
  93  int pos, paren, pstack, result = 0;
  94
  95  toys.exitval = 2;
  96  if (!strcmp("[", toys.which->name))
  97    if (!toys.optc || strcmp("]", toys.optargs[--toys.optc]))
  98      error_exit("Missing ']'");
  99
 100  // loop through command line arguments
 101  if (toys.optc) for (pos = paren = pstack = 0; ; pos++) {
 102    int len = toys.optc-pos;
 103
 104    if (!toys.optargs[pos]) perror_exit("need arg @%d", pos);
 105
 106    // Evaluate next test
 107    result = do_test(toys.optargs+pos, &len);
 108    pos += len;
 109    // Single argument could be ! ( or nonempty
 110    if (!len) {
 111      if (toys.optargs[pos+1]) {
 112        if (!strcmp("!", toys.optargs[pos])) {
 113          pstack ^= NOT;
 114          continue;
 115        }
 116        if (!strcmp("(", toys.optargs[pos])) {
 117          if (++paren>9) perror_exit("bad (");
 118          pstack <<= 3;
 119          continue;
 120        }
 121      }
 122      result = *toys.optargs[pos++];
 123    }
 124    s = toys.optargs[pos];
 125    for (;;) {
 126
 127      // Handle pending ! -a -o (the else means -o beats -a)
 128      if (pstack&NOT) result = !result;
 129      pstack &= ~NOT;
 130      if (pstack&OR) result = 1;
 131      else if (pstack&AND) result = 0;
 132
 133      // Do it again for every )
 134      if (!paren || !s || strcmp(")", s)) break;
 135      paren--;
 136      pstack >>= 3;
 137      s = toys.optargs[++pos];
 138    }
 139
 140    // Out of arguments?
 141    if (!s) {
 142      if (paren) perror_exit("need )");
 143      break;
 144    }
 145
 146    // are we followed by -a or -o?
 147
 148    if (!strcmp("-a", s)) {
 149      if (!result) pstack |= AND;
 150    } else if (!strcmp("-o", s)) {
 151      // -o flushes -a even if previous test was false
 152      pstack &=~AND;
 153      if (result) pstack |= OR;
 154    } else error_exit("too many arguments");
 155  }
 156
 157  // Invert C logic to get shell logic
 158  toys.exitval = !result;
 159}
 160