path: root/src/test.c

/* GNU test program (ksb and mjb) */

/* Modified to run with the GNU shell by bfox. */

/* Copyright (C) 1987-1993, 1994, 95, 1996 Free Software Foundation, Inc.

   This file is part of GNU Bash, the Bourne Again SHell.

   Bash is free software; you can redistribute it and/or modify it under
   the terms of the GNU General Public License as published by the Free
   Software Foundation; either version 2, or (at your option) any later
   version.

   Bash is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or
   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* Define TEST_STANDALONE to get the /bin/test version.  Otherwise, you get
   the shell builtin version. */
/* #define TEST_STANDALONE */

#include <config.h>
#include <stdio.h>
#include <sys/types.h>

#define TEST_STANDALONE 1

#if !defined (TEST_STANDALONE)
#  include "shell.h"
#  include "posixstat.h"
#  include "filecntl.h"
#else /* TEST_STANDALONE */
#  include "system.h"
#  include "group-member.h"
#  include "error.h"
#  if !defined (S_IXUGO)
#    define S_IXUGO 0111
#  endif /* S_IXUGO */
#  if defined (_POSIX_VERSION)
#    include <limits.h>
#  else /* !_POSIX_VERSION */
#    include <sys/param.h>
#  endif /* _POSIX_VERSION */
#define whitespace(c) (((c) == ' ') || ((c) == '\t'))
#define digit(c)  ((c) >= '0' && (c) <= '9')
#define digit_value(c) ((c) - '0')
char *program_name;
#endif /* TEST_STANDALONE */

#if !defined (_POSIX_VERSION)
#  include <sys/file.h>
#endif /* !_POSIX_VERSION */

#include <errno.h>
#ifndef errno
extern int errno;
#endif

#if !defined (STREQ)
#  define STREQ(a, b) ((a)[0] == (b)[0] && strcmp (a, b) == 0)
#endif /* !STREQ */

#if !defined (member)
#  define member(c, s) ((c) ? (strchr ((s), (c)) ? 1 : 0) : 0)
#endif /* !member */

extern gid_t getegid ();
extern uid_t geteuid ();

#if !defined (R_OK)
#define R_OK 4
#define W_OK 2
#define X_OK 1
#define F_OK 0
#endif /* R_OK */

/* This name is used solely when printing --version information.  */
#define COMMAND_NAME "test"

/* The following few defines control the truth and false output of each stage.
   TRUE and FALSE are what we use to compute the final output value.
   SHELL_BOOLEAN is the form which returns truth or falseness in shell terms.
   TRUTH_OR is how to do logical or with TRUE and FALSE.
   TRUTH_AND is how to do logical and with TRUE and FALSE..
   Default is TRUE = 1, FALSE = 0, TRUTH_OR = a | b, TRUTH_AND = a & b,
    SHELL_BOOLEAN = (!value). */
#define TRUE 1
#define FALSE 0
#define SHELL_BOOLEAN(value) (!(value))
#define TRUTH_OR(a, b) ((a) | (b))
#define TRUTH_AND(a, b) ((a) & (b))

#if defined (TEST_STANDALONE)
#  define test_exit(val) exit (val)
#else
   static jmp_buf test_exit_buf;
   static int test_error_return = 0;
#  define test_exit(val) test_error_return = val, longjmp (test_exit_buf, 1)
#endif /* !TEST_STANDALONE */

char *xrealloc ();

static int pos;		/* The offset of the current argument in ARGV. */
static int argc;	/* The number of arguments present in ARGV. */
static char **argv;	/* The argument list. */

static int unop __P ((int op));
static int binop __P ((char *s));
static int unary_operator __P ((void));
static int binary_operator __P ((void));
static int two_arguments __P ((void));
static int three_arguments __P ((void));
static int posixtest __P ((void));

static int expr __P ((void));
static int term __P ((void));
static int and __P ((void));
static int or __P ((void));

#if __GNUC__ >= 2 && defined (__GNUC_MINOR__) \
    && __GNUC_MINOR__ >= 5 && !defined (__STRICT_ANSI__)
#define NO_RETURN_ATTRIBUTE __attribute__ ((noreturn))
#else
#define NO_RETURN_ATTRIBUTE /* empty */
#endif

static void test_syntax_error __P ((char *format, char *arg)) NO_RETURN_ATTRIBUTE;
static void beyond __P ((void)) NO_RETURN_ATTRIBUTE;

static void
test_syntax_error (char *format, char *arg)
{
  fprintf (stderr, "%s: ", argv[0]);
  fprintf (stderr, format, arg);
  fflush (stderr);
  test_exit (SHELL_BOOLEAN (FALSE));
}

/* A wrapper for stat () which disallows pathnames that are empty strings. */
static int
test_stat (char *path, struct stat *finfo)
{
  if (*path == '\0')
    {
      errno = ENOENT;
      return (-1);
    }
  return (stat (path, finfo));
}

/* Do the same thing access(2) does, but use the effective uid and gid,
   and don't make the mistake of telling root that any file is executable.
   But this loses when the containing filesystem is mounted e.g. read-only.  */
static int
eaccess (char *path, int mode)
{
  struct stat st;
  static int euid = -1;

  if (test_stat (path, &st) < 0)
    return (-1);

  if (euid == -1)
    euid = geteuid ();

  if (euid == 0)
    {
      /* Root can read or write any file. */
      if (mode != X_OK)
	return (0);

      /* Root can execute any file that has any one of the execute
	 bits set. */
      if (st.st_mode & S_IXUGO)
	return (0);
    }

  if (st.st_uid == euid)        /* owner */
    mode <<= 6;
  else if (group_member (st.st_gid))
    mode <<= 3;

  if (st.st_mode & mode)
    return (0);

  return (-1);
}

/* Increment our position in the argument list.  Check that we're not
   past the end of the argument list.  This check is supressed if the
   argument is FALSE.  Made a macro for efficiency. */
#define advance(f)							\
  do									\
    {									\
      ++pos;								\
      if ((f) && pos >= argc)						\
	beyond ();							\
    }									\
  while (0)

#if !defined (advance)
static int
advance (int f)
{
  ++pos;

  if (f && pos >= argc)
    beyond ();
}
#endif /* advance */

#define unary_advance() 						\
  do									\
    {									\
      advance (1);							\
      ++pos;								\
    }									\
  while (0)

/*
 * beyond - call when we're beyond the end of the argument list (an
 *	error condition)
 */
static void
beyond (void)
{
  test_syntax_error (_("argument expected\n"), NULL);
}

/* Syntax error for when an integer argument was expected, but
   something else was found. */
static void
integer_expected_error (char *pch)
{
  test_syntax_error (_("integer expression expected %s\n"), pch);
}

/* Return nonzero if the characters pointed to by STRING constitute a
   valid number.  Stuff the converted number into RESULT if RESULT is
   a non-null pointer to a long. */
static int
isint (register char *string, long int *result)
{
  int sign;
  long value;

  sign = 1;
  value = 0;

  if (result)
    *result = 0;

  /* Skip leading whitespace characters. */
  while (whitespace (*string))
    string++;

  if (!*string)
    return (0);

  /* We allow leading `-' or `+'. */
  if (*string == '-' || *string == '+')
    {
      if (!digit (string[1]))
	return (0);

      if (*string == '-')
	sign = -1;

      string++;
    }

  while (digit (*string))
    {
      if (result)
	value = (value * 10) + digit_value (*string);
      string++;
    }

  /* Skip trailing whitespace, if any. */
  while (whitespace (*string))
    string++;

  /* Error if not at end of string. */
  if (*string)
    return (0);

  if (result)
    {
      value *= sign;
      *result = value;
    }

  return (1);
}

/* Find the modification time of FILE, and stuff it into AGE, a pointer
   to a long.  Return nonzero if successful, else zero. */
static int
age_of (char *filename, long int *age)
{
  struct stat finfo;

  if (test_stat (filename, &finfo) < 0)
    return (0);

  if (age)
    *age = finfo.st_mtime;

  return (1);
}

/*
 * term - parse a term and return 1 or 0 depending on whether the term
 *	evaluates to true or false, respectively.
 *
 * term ::=
 *	'-'('h'|'d'|'f'|'r'|'s'|'w'|'c'|'b'|'p'|'u'|'g'|'k') filename
 *	'-'('L'|'x') filename
 * 	'-t' [ int ]
 *	'-'('z'|'n') string
 *	string
 *	string ('!='|'=') string
 *	<int> '-'(eq|ne|le|lt|ge|gt) <int>
 *	file '-'(nt|ot|ef) file
 *	'(' <expr> ')'
 * int ::=
 *	'-l' string
 *	positive and negative integers
 */
static int
term (void)
{
  int value;

  if (pos >= argc)
    beyond ();

  /* Deal with leading "not"'s. */
  if ('!' == argv[pos][0] && '\000' == argv[pos][1])
    {
      value = FALSE;
      while (pos < argc && '!' == argv[pos][0] && '\000' == argv[pos][1])
	{
	  advance (1);
	  value ^= (TRUE);
	}

      return (value ^ (term ()));
    }

  /* A paren-bracketed argument. */
  if (argv[pos][0] == '(' && !argv[pos][1])
    {
      advance (1);
      value = expr ();
      if (!argv[pos])
	test_syntax_error (_("')' expected\n"), NULL);
      else
        if (argv[pos][0] != ')' || argv[pos][1])
	  test_syntax_error (_("')' expected, found %s\n"), argv[pos]);
      advance (0);
      return (TRUE == (value));
    }

  /* are there enough arguments left that this could be dyadic? */
  if (((pos + 3 <= argc) && binop (argv[pos + 1])) ||
      ((pos + 4 <= argc && STREQ (argv[pos], "-l") && binop (argv[pos + 2]))))
    value = binary_operator ();

  /* Might be a switch type argument */
  else if ('-' == argv[pos][0] && 0 == argv[pos][2])
    {
      if (unop (argv[pos][1]))
	value = unary_operator ();
      else
	test_syntax_error (_("%s: unary operator expected\n"), argv[pos]);
    }
  else
    {
      value = (argv[pos][0] != '\0');
      advance (0);
    }

  return (value);
}

static int
binary_operator (void)
{
  register int op;
  struct stat stat_buf, stat_spare;
  long int l, r, value;
  /* Are the left and right integer expressions of the form '-l string'? */
  int l_is_l, r_is_l;

  if (strcmp (argv[pos], "-l") == 0)
    {
      l_is_l = 1;
      op = pos + 2;

      /* Make sure that OP is still a valid binary operator. */
      if ((op >= argc - 1) || (binop (argv[op]) == 0))
	test_syntax_error (_("%s: binary operator expected\n"), argv[op]);

      advance (0);
    }
  else
    {
      l_is_l = 0;
      op = pos + 1;
    }

  if ((op < argc - 2) && (strcmp (argv[op + 1], "-l") == 0))
    {
      r_is_l = 1;
      advance (0);
    }
  else
    r_is_l = 0;

  if (argv[op][0] == '-')
    {
      /* check for eq, nt, and stuff */
      switch (argv[op][1])
	{
	default:
	  break;

	case 'l':
	  if (argv[op][2] == 't' && !argv[op][3])
	    {
	      /* lt */
	      if (l_is_l)
		l = strlen (argv[op - 1]);
	      else
		{
		  if (!isint (argv[op - 1], &l))
		    integer_expected_error (_("before -lt"));
		}

	      if (r_is_l)
		r = strlen (argv[op + 2]);
	      else
		{
		  if (!isint (argv[op + 1], &r))
		    integer_expected_error (_("after -lt"));
		}
	      pos += 3;
	      return (TRUE == (l < r));
	    }

	  if (argv[op][2] == 'e' && !argv[op][3])
	    {
	      /* le */
	      if (l_is_l)
		l = strlen (argv[op - 1]);
	      else
		{
		  if (!isint (argv[op - 1], &l))
		    integer_expected_error (_("before -le"));
		}
	      if (r_is_l)
		r = strlen (argv[op + 2]);
	      else
		{
		  if (!isint (argv[op + 1], &r))
		    integer_expected_error (_("after -le"));
		}
	      pos += 3;
	      return (TRUE == (l <= r));
	    }
	  break;

	case 'g':
	  if (argv[op][2] == 't' && !argv[op][3])
	    {
	      /* gt integer greater than */
	      if (l_is_l)
		l = strlen (argv[op - 1]);
	      else
		{
		  if (!isint (argv[op - 1], &l))
		    integer_expected_error (_("before -gt"));
		}
	      if (r_is_l)
		r = strlen (argv[op + 2]);
	      else
		{
		  if (!isint (argv[op + 1], &r))
		    integer_expected_error (_("after -gt"));
		}
	      pos += 3;
	      return (TRUE == (l > r));
	    }

	  if (argv[op][2] == 'e' && !argv[op][3])
	    {
	      /* ge - integer greater than or equal to */
	      if (l_is_l)
		l = strlen (argv[op - 1]);
	      else
		{
		  if (!isint (argv[op - 1], &l))
		    integer_expected_error (_("before -ge"));
		}
	      if (r_is_l)
		r = strlen (argv[op + 2]);
	      else
		{
		  if (!isint (argv[op + 1], &r))
		    integer_expected_error (_("after -ge"));
		}
	      pos += 3;
	      return (TRUE == (l >= r));
	    }
	  break;

	case 'n':
	  if (argv[op][2] == 't' && !argv[op][3])
	    {
	      /* nt - newer than */
	      pos += 3;
	      if (l_is_l || r_is_l)
		test_syntax_error (_("-nt does not accept -l\n"), NULL);
	      if (age_of (argv[op - 1], &l) && age_of (argv[op + 1], &r))
		return (TRUE == (l > r));
	      else
		return (FALSE);
	    }

	  if (argv[op][2] == 'e' && !argv[op][3])
	    {
	      /* ne - integer not equal */
	      if (l_is_l)
		l = strlen (argv[op - 1]);
	      else
		{
		  if (!isint (argv[op - 1], &l))
		    integer_expected_error (_("before -ne"));
		}
	      if (r_is_l)
		r = strlen (argv[op + 2]);
	      else
		{
		  if (!isint (argv[op + 1], &r))
		    integer_expected_error (_("after -ne"));
		}
	      pos += 3;
	      return (TRUE == (l != r));
	    }
	  break;

	case 'e':
	  if (argv[op][2] == 'q' && !argv[op][3])
	    {
	      /* eq - integer equal */
	      if (l_is_l)
		l = strlen (argv[op - 1]);
	      else
		{
		  if (!isint (argv[op - 1], &l))
		    integer_expected_error (_("before -eq"));
		}
	      if (r_is_l)
		r = strlen (argv[op + 2]);
	      else
		{
		  if (!isint (argv[op + 1], &r))
		    integer_expected_error (_("after -eq"));
		}
	      pos += 3;
	      return (TRUE == (l == r));
	    }

	  if (argv[op][2] == 'f' && !argv[op][3])
	    {
	      /* ef - hard link? */
	      pos += 3;
	      if (l_is_l || r_is_l)
		test_syntax_error (_("-ef does not accept -l\n"), NULL);
	      if (stat (argv[op - 1], &stat_buf) < 0)
		return (FALSE);
	      if (stat (argv[op + 1], &stat_spare) < 0)
		return (FALSE);
	      return (TRUE ==
		      (stat_buf.st_dev == stat_spare.st_dev &&
		       stat_buf.st_ino == stat_spare.st_ino));
	    }
	  break;

	case 'o':
	  if ('t' == argv[op][2] && '\000' == argv[op][3])
	    {
	      /* ot - older than */
	      pos += 3;
	      if (l_is_l || r_is_l)
		test_syntax_error (_("-nt does not accept -l\n"), NULL);
	      if (age_of (argv[op - 1], &l) && age_of (argv[op + 1], &r))
		return (TRUE == (l < r));
	      return (FALSE);
	    }
	  break;
	}
      test_syntax_error (_("unknown binary operator"), argv[op]);
    }

  if (argv[op][0] == '=' && !argv[op][1])
    {
      value = (strcmp (argv[pos], argv[pos + 2]) == 0);
      pos += 3;
      return (TRUE == value);
    }

  if (strcmp (argv[op], "!=") == 0)
    {
      value = (strcmp (argv[pos], argv[pos + 2]) != 0);
      pos += 3;
      return (TRUE == value);
    }

  /* Not reached.  */
  abort ();
}

static int
unary_operator (void)
{
  long r, value;
  struct stat stat_buf;

  switch (argv[pos][1])
    {
    default:
      return (FALSE);

      /* All of the following unary operators use unary_advance (), which
	 checks to make sure that there is an argument, and then advances
	 pos right past it.  This means that pos - 1 is the location of the
	 argument. */

    case 'a':			/* file exists in the file system? */
    case 'e':
      unary_advance ();
      value = -1 != test_stat (argv[pos - 1], &stat_buf);
      return (TRUE == value);

    case 'r':			/* file is readable? */
      unary_advance ();
      value = -1 != eaccess (argv[pos - 1], R_OK);
      return (TRUE == value);

    case 'w':			/* File is writeable? */
      unary_advance ();
      value = -1 != eaccess (argv[pos - 1], W_OK);
      return (TRUE == value);

    case 'x':			/* File is executable? */
      unary_advance ();
      value = -1 != eaccess (argv[pos - 1], X_OK);
      return (TRUE == value);

    case 'O':			/* File is owned by you? */
      unary_advance ();
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);

      return (TRUE == (geteuid () == stat_buf.st_uid));

    case 'G':			/* File is owned by your group? */
      unary_advance ();
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);

      return (TRUE == (getegid () == stat_buf.st_gid));

    case 'f':			/* File is a file? */
      unary_advance ();
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);

      /* Under POSIX, -f is true if the given file exists
	 and is a regular file. */
      return (TRUE == ((S_ISREG (stat_buf.st_mode)) ||
		       (0 == (stat_buf.st_mode & S_IFMT))));

    case 'd':			/* File is a directory? */
      unary_advance ();
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);

      return (TRUE == (S_ISDIR (stat_buf.st_mode)));

    case 's':			/* File has something in it? */
      unary_advance ();
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);

      return (TRUE == (stat_buf.st_size > (off_t) 0));

    case 'S':			/* File is a socket? */
#if !defined (S_ISSOCK)
      return (FALSE);
#else
      unary_advance ();

      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);

      return (TRUE == (S_ISSOCK (stat_buf.st_mode)));
#endif				/* S_ISSOCK */

    case 'c':			/* File is character special? */
      unary_advance ();
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);

      return (TRUE == (S_ISCHR (stat_buf.st_mode)));

    case 'b':			/* File is block special? */
      unary_advance ();
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);

      return (TRUE == (S_ISBLK (stat_buf.st_mode)));

    case 'p':			/* File is a named pipe? */
      unary_advance ();
#ifndef S_ISFIFO
      return (FALSE);
#else
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);
      return (TRUE == (S_ISFIFO (stat_buf.st_mode)));
#endif				/* S_ISFIFO */

    case 'L':			/* Same as -h  */
      /*FALLTHROUGH*/

    case 'h':			/* File is a symbolic link? */
      unary_advance ();
#ifndef S_ISLNK
      return (FALSE);
#else
      /* An empty filename is not a valid pathname. */
      if ((argv[pos - 1][0] == '\0') ||
	  (lstat (argv[pos - 1], &stat_buf) < 0))
	return (FALSE);

      return (TRUE == (S_ISLNK (stat_buf.st_mode)));
#endif				/* S_IFLNK */

    case 'u':			/* File is setuid? */
      unary_advance ();
#ifndef S_ISUID
      return (FALSE);
#else
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);

      return (TRUE == (0 != (stat_buf.st_mode & S_ISUID)));
#endif

    case 'g':			/* File is setgid? */
      unary_advance ();
#ifndef S_ISGID
      return (FALSE);
#else
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);

      return (TRUE == (0 != (stat_buf.st_mode & S_ISGID)));
#endif

    case 'k':			/* File has sticky bit set? */
      unary_advance ();
      if (test_stat (argv[pos - 1], &stat_buf) < 0)
	return (FALSE);
#ifndef S_ISVTX
      /* This is not Posix, and is not defined on some Posix systems. */
      return (FALSE);
#else
      return (TRUE == (0 != (stat_buf.st_mode & S_ISVTX)));
#endif

    case 't':			/* File (fd) is a terminal?  (fd) defaults to stdout. */
      advance (0);
      if (pos < argc && isint (argv[pos], &r))
	{
	  advance (0);
	  return (TRUE == (isatty ((int) r)));
	}
      return (TRUE == (isatty (1)));

    case 'n':			/* True if arg has some length. */
      unary_advance ();
      return (TRUE == (argv[pos - 1][0] != 0));

    case 'z':			/* True if arg has no length. */
      unary_advance ();
      return (TRUE == (argv[pos - 1][0] == '\0'));
    }
}

/*
 * and:
 *	term
 *	term '-a' and
 */
static int
and (void)
{
  int value;

  value = term ();
  while ((pos < argc) && strcmp (argv[pos], "-a") == 0)
    {
      advance (0);
      value = TRUTH_AND (value, and ());
    }
  return (TRUE == value);
}

/*
 * or:
 *	and
 *	and '-o' or
 */
static int
or (void)
{
  int value;

  value = and ();

  while ((pos < argc) && strcmp (argv[pos], "-o") == 0)
    {
      advance (0);
      value = TRUTH_OR (value, or ());
    }

  return (TRUE == value);
}

/*
 * expr:
 *	or
 */
static int
expr (void)
{
  if (pos >= argc)
    beyond ();

  return (FALSE ^ (or ()));		/* Same with this. */
}

/* Return TRUE if S is one of the test command's binary operators. */
static int
binop (char *s)
{
  return ((STREQ (s,   "=")) || (STREQ (s,  "!=")) || (STREQ (s, "-nt")) ||
	  (STREQ (s, "-ot")) || (STREQ (s, "-ef")) || (STREQ (s, "-eq")) ||
	  (STREQ (s, "-ne")) || (STREQ (s, "-lt")) || (STREQ (s, "-le")) ||
	  (STREQ (s, "-gt")) || (STREQ (s, "-ge")));
}

/* Return nonzero if OP is one of the test command's unary operators. */
static int
unop (int op)
{
  return (member (op, "abcdefgkLhprsStuwxOGnz"));
}

static int
two_arguments (void)
{
  int value;

  if (STREQ (argv[pos], "!"))
    value = strlen (argv[pos+1]) == 0;
  else if ((argv[pos][0] == '-') && (argv[pos][2] == '\0'))
    {
      if (unop (argv[pos][1]))
	value = unary_operator ();
      else
	test_syntax_error (_("%s: unary operator expected\n"), argv[pos]);
    }
  else
    beyond ();
  return (value);
}

static int
three_arguments (void)
{
  int value;

  if (STREQ (argv[pos], "!"))
    {
      advance (1);
      value = !two_arguments ();
    }
  else if (binop (argv[pos+1]))
    {
      value = binary_operator ();
      pos = argc;
    }
  else if ((STREQ (argv[pos+1], "-a")) || (STREQ (argv[pos+1], "-o")) ||
	   (argv[pos][0] == '('))
    value = expr ();
  else
    test_syntax_error (_("%s: binary operator expected\n"), argv[pos+1]);
  return (value);
}

/* This is an implementation of a Posix.2 proposal by David Korn. */
static int
posixtest (void)
{
  int value;

  switch (argc - 1)	/* one extra passed in */
    {
      case 0:
	value = FALSE;
	pos = argc;
	break;

      case 1:
	value = strlen (argv[1]) != 0;
	pos = argc;
	break;

      case 2:
	value = two_arguments ();
	pos = argc;
	break;

      case 3:
	value = three_arguments ();
	break;

      case 4:
	if (STREQ (argv[pos], "!"))
	  {
	    advance (1);
	    value = !three_arguments ();
	    break;
	  }
	/* FALLTHROUGH */
      case 5:
      default:
	value = expr ();
    }

  return (value);
}

#if defined (TEST_STANDALONE)
#include "long-options.h"

static void
usage (int status)
{
  if (status != 0)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
	     program_name);
  else
    {
      printf (_("\
Usage: %s EXPRESSION\n\
  or:  [ EXPRESSION ]\n\
  or:  %s OPTION\n\
"),
	      program_name, program_name);
      printf (_("\
Exit with the status determined by EXPRESSION.\n\
\n\
  --help      display this help and exit\n\
  --version   output version information and exit\n\
\n\
EXPRESSION is true or false and sets exit status.  It is one of:\n\
"));
      printf (_("\
\n\
  ( EXPRESSION )               EXPRESSION is true\n\
  ! EXPRESSION                 EXPRESSION is false\n\
  EXPRESSION1 -a EXPRESSION2   both EXPRESSION1 and EXPRESSION2 are true\n\
  EXPRESSION1 -o EXPRESSION2   either EXPRESSION1 or EXPRESSION2 is true\n\
\n\
  [-n] STRING          the length of STRING is nonzero\n\
  -z STRING            the length of STRING is zero\n\
  STRING1 = STRING2    the strings are equal\n\
  STRING1 != STRING2   the strings are not equal\n\
\n\
  INTEGER1 -eq INTEGER2   INTEGER1 is equal to INTEGER2\n\
  INTEGER1 -ge INTEGER2   INTEGER1 is greater than or equal to INTEGER2\n\
  INTEGER1 -gt INTEGER2   INTEGER1 is greater than INTEGER2\n\
  INTEGER1 -le INTEGER2   INTEGER1 is less than or equal to INTEGER2\n\
  INTEGER1 -lt INTEGER2   INTEGER1 is less than INTEGER2\n\
  INTEGER1 -ne INTEGER2   INTEGER1 is not equal to INTEGER2\n\
"));
      printf (_("\
\n\
  FILE1 -ef FILE2   FILE1 and FILE2 have the same device and inode numbers\n\
  FILE1 -nt FILE2   FILE1 is newer (modification date) than FILE2\n\
  FILE1 -ot FILE2   FILE1 is older than FILE2\n\
\n\
  -G FILE     FILE exists and is owned by the effective group ID\n\
  -L FILE     FILE exists and is a symbolic link\n\
  -O FILE     FILE exists and is owned by the effective user ID\n\
  -S FILE     FILE exists and is a socket\n\
  -b FILE     FILE exists and is block special\n\
  -c FILE     FILE exists and is character special\n\
  -d FILE     FILE exists and is a directory\n\
  -e FILE     FILE exists\n\
  -f FILE     FILE exists and is a regular file\n\
  -g FILE     FILE exists and is set-group-ID\n\
  -k FILE     FILE exists and has its sticky bit set\n\
  -p FILE     FILE exists and is a named pipe\n\
  -r FILE     FILE exists and is readable\n\
  -s FILE     FILE exists and has a size greater than zero\n\
  -t [FD]     file descriptor FD (stdout by default) is opened on a terminal\n\
  -u FILE     FILE exists and its set-user-ID bit is set\n\
  -w FILE     FILE exists and is writable\n\
  -x FILE     FILE exists and is executable\n\
"));
      printf (_("\
\n\
Beware that parentheses need to be escaped (e.g., by backslashes) for shells.\n\
INTEGER may also be -l STRING, which evaluates to the length of STRING.\n\
"));
    }
  exit (status);
}
#endif /* TEST_STANDALONE */

#if !defined (TEST_STANDALONE)
# define main test_command
#endif

/*
 * [:
 *	'[' expr ']'
 * test:
 *	test expr
 */
int
main (int margc, char **margv)
{
  int value;

#if !defined (TEST_STANDALONE)
  int code;

  code = setjmp (test_exit_buf);

  if (code)
    return (test_error_return);
#else /* TEST_STANDALONE */
  program_name = margv[0];
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);
#endif /* TEST_STANDALONE */

  argv = margv;

  if (margv[0] && strcmp (margv[0], "[") == 0)
    {
      /* Don't recognize --help or --version if POSIXLY_CORRECT is set.  */
      if (getenv ("POSIXLY_CORRECT") == NULL)
	parse_long_options (argc, argv, COMMAND_NAME, PACKAGE_VERSION, usage);

      --margc;

      if (margc < 2)
	test_exit (SHELL_BOOLEAN (FALSE));

      if (margv[margc] && strcmp (margv[margc], "]") != 0)
	test_syntax_error (_("missing `]'\n"), NULL);
    }

  argc = margc;
  pos = 1;

  if (pos >= argc)
    test_exit (SHELL_BOOLEAN (FALSE));

  parse_long_options (argc, argv, COMMAND_NAME, PACKAGE_VERSION, usage);
  value = posixtest ();

  if (pos != argc)
    test_syntax_error (_("too many arguments\n"), NULL);

  test_exit (SHELL_BOOLEAN (value));
}