/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <locale.h>
#include <libgen.h>

#define	NBUF	4096		/* Read this much at a time */
#define	BSIZE	512		/* Bytes per block */

typedef	unsigned long	CRC;	/* 32 bit (at least) crc size */

static	uchar_t	buf[NBUF];	/* Input buffer */
static	uchar_t	tflag;		/* More than one input file */
static	uchar_t	many;
static	CRC	filecrc;	/* CRC for this file */
static	CRC	totcrc;		/* Total of all files */
static	long long totbytes;	/* Total bytes read */
static	ulong_t	bsize = 1;	/* block size */

static	int	sum(const char *fn);
static	int	usage(void);
static	CRC	docrcposix(CRC crcval, uchar_t *bp, ulong_t n);
static	CRC	postprocess(CRC S, long long n);

static	CRC	(*crcfunc)(CRC crcval, uchar_t *bp, ulong_t n) = docrcposix;
static void	m_crcposix(ulong_t *, const uchar_t *, size_t);

/*
 * Mainline for cksum.
 */
int
main(int argc, char *argv[])
{
	int	c;
	int	exstat = 0;

	(void) setlocale(LC_ALL, "");

#if !defined(TEXT_DOMAIN)
#define	TEXT_DOMAIN	"SYS_TEST"
#endif
	(void) textdomain(TEXT_DOMAIN);

	tflag = many = 0;
	totbytes = totcrc = 0;
	while ((c = getopt(argc, argv, "")) != -1) {
		switch (c) {
		case 't':		/* this is non-functional for now */
			tflag++;
			break;
		default:
			return (usage());
		}
	}

	/* Sum from standard input? */
	if ((many = optind < argc) == 0)
		return (sum(NULL));

	/* Sum each file argument. */
	for (; optind < argc; ++optind)
		exstat |= sum(argv[optind]);

	if (tflag) {
		(void) printf("%lu", postprocess(totcrc, totbytes));
		(void) printf(gettext("\t%lld\t   Total\n"),
			(long long)((totbytes + bsize - 1) / bsize));
	}
	return (exstat);
}

/*
 * Compute checksum for one file.
 */
static int
sum(const char *fn)
{
	int	n;
	int	fd;
	long long bytes = 0;

	if (fn == NULL || (fn[0] == '-' && fn[1] == '\0'))
		fd = 0;
	else if ((fd = open(fn, O_RDONLY)) < 0) {
		(void) fprintf(stderr, gettext("cksum: input file \"%s\": "),
			fn);
		perror("");
		return (1);
	}
	filecrc = 0;
	while ((n = read(fd, (char *)buf, sizeof (buf))) > 0) {
		bytes += n;
		filecrc = (*crcfunc) (filecrc, buf, n);
		if (tflag)
			totcrc = (*crcfunc) (totcrc, buf, n);
	}
	(void) close(fd);
	totbytes += bytes;
	(void) printf("%lu", postprocess(filecrc, bytes));
	(void) printf("\t%lld", (long long)((bytes + bsize - 1) / bsize));
	if (many) {
		(void) printf("\t%s", (fn[0] == '-' && fn[1] == '\0') ?
			gettext("[standard input]") : fn);
	}
	if (n < 0)
		(void) fputs(gettext(" [read error]"), stdout);
	(void) putchar('\n');
	return (n == 0 ? 0 : 1);
}


/*
 * Do CRC-POSIX function by calling a library entry point that has a
 * slightly different calling sequence.
 */
static	CRC
docrcposix(CRC crcval, uchar_t *bp, ulong_t n)
{
	m_crcposix(&crcval, bp, n);
	return (crcval);
}

/*
 * Sum algorithms require various kinds of post-processing.
 * The 'S' and 'R' variables are from the POSIX.2 (Draft 8?) description
 * of the "sum" utility.
 * This code makes no assumption about word size except that a
 * "CRC" type holds at least 32 bits.
 */
static	CRC
postprocess(CRC S, long long n)
{
	/*
	 * POSIX tacks on significant bytes of the length so that
	 * different length sequences of '\0' have different sums;
	 * then it complements sum.
	 */
	uchar_t	char_n[sizeof (n)];
	ulong_t	i;

	for (i = 0; n != 0; n >>= 8, ++i)
		char_n[i] = n & 0xFF;
	return (~docrcposix(S, char_n, i));
}

/*
 * usage message for cksum
 */
static int
usage()
{
	(void) fprintf(stderr, gettext("Usage: cksum [file ...]\n"));
	return (2);
}

/*
 * crcposix -- compute posix.2 compatable 32 bit CRC
 *
 * The POSIX.2 (draft 10) CRC algorithm.
 * This is a 32 bit CRC with polynomial
 *	x**32 + x**26 + x**23 + x**22 + x**16 + x**12 + x**11 + x**10 +
 *	x**8 + x**7 + x**5 + x**4 + x**2 + x**1 + x**0
 */

/* layout is from the POSIX.2 Rationale */
static ulong_t crctab_posix[256] = {
	0x00000000,
	0x04C11DB7, 0x09823B6E, 0x0D4326D9, 0x130476DC, 0x17C56B6B,
	0x1A864DB2, 0x1E475005, 0x2608EDB8, 0x22C9F00F, 0x2F8AD6D6,
	0x2B4BCB61, 0x350C9B64, 0x31CD86D3, 0x3C8EA00A, 0x384FBDBD,
	0x4C11DB70, 0x48D0C6C7, 0x4593E01E, 0x4152FDA9, 0x5F15ADAC,
	0x5BD4B01B, 0x569796C2, 0x52568B75, 0x6A1936C8, 0x6ED82B7F,
	0x639B0DA6, 0x675A1011, 0x791D4014, 0x7DDC5DA3, 0x709F7B7A,
	0x745E66CD, 0x9823B6E0, 0x9CE2AB57, 0x91A18D8E, 0x95609039,
	0x8B27C03C, 0x8FE6DD8B, 0x82A5FB52, 0x8664E6E5, 0xBE2B5B58,
	0xBAEA46EF, 0xB7A96036, 0xB3687D81, 0xAD2F2D84, 0xA9EE3033,
	0xA4AD16EA, 0xA06C0B5D, 0xD4326D90, 0xD0F37027, 0xDDB056FE,
	0xD9714B49, 0xC7361B4C, 0xC3F706FB, 0xCEB42022, 0xCA753D95,
	0xF23A8028, 0xF6FB9D9F, 0xFBB8BB46, 0xFF79A6F1, 0xE13EF6F4,
	0xE5FFEB43, 0xE8BCCD9A, 0xEC7DD02D, 0x34867077, 0x30476DC0,
	0x3D044B19, 0x39C556AE, 0x278206AB, 0x23431B1C, 0x2E003DC5,
	0x2AC12072, 0x128E9DCF, 0x164F8078, 0x1B0CA6A1, 0x1FCDBB16,
	0x018AEB13, 0x054BF6A4, 0x0808D07D, 0x0CC9CDCA, 0x7897AB07,
	0x7C56B6B0, 0x71159069, 0x75D48DDE, 0x6B93DDDB, 0x6F52C06C,
	0x6211E6B5, 0x66D0FB02, 0x5E9F46BF, 0x5A5E5B08, 0x571D7DD1,
	0x53DC6066, 0x4D9B3063, 0x495A2DD4, 0x44190B0D, 0x40D816BA,
	0xACA5C697, 0xA864DB20, 0xA527FDF9, 0xA1E6E04E, 0xBFA1B04B,
	0xBB60ADFC, 0xB6238B25, 0xB2E29692, 0x8AAD2B2F, 0x8E6C3698,
	0x832F1041, 0x87EE0DF6, 0x99A95DF3, 0x9D684044, 0x902B669D,
	0x94EA7B2A, 0xE0B41DE7, 0xE4750050, 0xE9362689, 0xEDF73B3E,
	0xF3B06B3B, 0xF771768C, 0xFA325055, 0xFEF34DE2, 0xC6BCF05F,
	0xC27DEDE8, 0xCF3ECB31, 0xCBFFD686, 0xD5B88683, 0xD1799B34,
	0xDC3ABDED, 0xD8FBA05A, 0x690CE0EE, 0x6DCDFD59, 0x608EDB80,
	0x644FC637, 0x7A089632, 0x7EC98B85, 0x738AAD5C, 0x774BB0EB,
	0x4F040D56, 0x4BC510E1, 0x46863638, 0x42472B8F, 0x5C007B8A,
	0x58C1663D, 0x558240E4, 0x51435D53, 0x251D3B9E, 0x21DC2629,
	0x2C9F00F0, 0x285E1D47, 0x36194D42, 0x32D850F5, 0x3F9B762C,
	0x3B5A6B9B, 0x0315D626, 0x07D4CB91, 0x0A97ED48, 0x0E56F0FF,
	0x1011A0FA, 0x14D0BD4D, 0x19939B94, 0x1D528623, 0xF12F560E,
	0xF5EE4BB9, 0xF8AD6D60, 0xFC6C70D7, 0xE22B20D2, 0xE6EA3D65,
	0xEBA91BBC, 0xEF68060B, 0xD727BBB6, 0xD3E6A601, 0xDEA580D8,
	0xDA649D6F, 0xC423CD6A, 0xC0E2D0DD, 0xCDA1F604, 0xC960EBB3,
	0xBD3E8D7E, 0xB9FF90C9, 0xB4BCB610, 0xB07DABA7, 0xAE3AFBA2,
	0xAAFBE615, 0xA7B8C0CC, 0xA379DD7B, 0x9B3660C6, 0x9FF77D71,
	0x92B45BA8, 0x9675461F, 0x8832161A, 0x8CF30BAD, 0x81B02D74,
	0x857130C3, 0x5D8A9099, 0x594B8D2E, 0x5408ABF7, 0x50C9B640,
	0x4E8EE645, 0x4A4FFBF2, 0x470CDD2B, 0x43CDC09C, 0x7B827D21,
	0x7F436096, 0x7200464F, 0x76C15BF8, 0x68860BFD, 0x6C47164A,
	0x61043093, 0x65C52D24, 0x119B4BE9, 0x155A565E, 0x18197087,
	0x1CD86D30, 0x029F3D35, 0x065E2082, 0x0B1D065B, 0x0FDC1BEC,
	0x3793A651, 0x3352BBE6, 0x3E119D3F, 0x3AD08088, 0x2497D08D,
	0x2056CD3A, 0x2D15EBE3, 0x29D4F654, 0xC5A92679, 0xC1683BCE,
	0xCC2B1D17, 0xC8EA00A0, 0xD6AD50A5, 0xD26C4D12, 0xDF2F6BCB,
	0xDBEE767C, 0xE3A1CBC1, 0xE760D676, 0xEA23F0AF, 0xEEE2ED18,
	0xF0A5BD1D, 0xF464A0AA, 0xF9278673, 0xFDE69BC4, 0x89B8FD09,
	0x8D79E0BE, 0x803AC667, 0x84FBDBD0, 0x9ABC8BD5, 0x9E7D9662,
	0x933EB0BB, 0x97FFAD0C, 0xAFB010B1, 0xAB710D06, 0xA6322BDF,
	0xA2F33668, 0xBCB4666D, 0xB8757BDA, 0xB5365D03, 0xB1F740B4
};

/*
 * crcposix -- compute posix.2 compatible 32 bit CRC
 */
void
m_crcposix(crcp, bp, n)
ulong_t *crcp;
const uchar_t *bp;
size_t n;
{
	while (n-- > 0)
	    *crcp = (*crcp<<8) ^ crctab_posix[(uchar_t)((*crcp>>24)^*bp++)];
}