busybox/coreutils/dos2unix.c

/*
 * dos2unix for BusyBox
 *
 * dos2unix '\n' convertor 0.5.0
 *   based on Unix2Dos 0.9.0 by Peter Hanecak (made 19.2.1997)
 * Copyright 1997,.. by Peter Hanecak <hanecak@megaloman.sk>.
 * All rights reserved.
 *
 * dos2unix filters reading input from stdin and writing output to stdout.
 * Without arguments it reverts the format (e.i. if source is in UNIX format,
 * output is in DOS format and vice versa).
 *
 * This program 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
 * of the License, or (at your option) any later version.
 *
 * This program 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.
 *
 * See the COPYING file for license information.
 */

#include <string.h>
#include <unistd.h>
#include <stdint.h>
#include <fcntl.h>
#include <sys/time.h>
#include "busybox.h"

#define CT_UNIX2DOS     1
#define CT_DOS2UNIX     2

/* We are making a lame pseudo-random string generator here.  in
 * convert(), each pass through the while loop will add more and more
 * stuff into value, which is _supposed_ to wrap.  We don't care about
 * it being accurate.  We care about it being messy, since we use it
 * to pick a random letter to add to out temporary file. */
typedef unsigned long int bb_uint64_t;

/* if fn is NULL then input is stdin and output is stdout */
static int convert(char *fn, int ConvType)
{
	int c, fd;
	struct timeval tv;
	RESERVE_CONFIG_BUFFER(tempFn, BUFSIZ);
	static bb_uint64_t value=0;
	FILE *in, *out;

	if (fn != NULL) {
		in = bb_xfopen(fn, "rw");
		safe_strncpy(tempFn, fn, sizeof(tempFn));
		c = strlen(tempFn);
		tempFn[c] = '.';
		while(1) {
		    /* tempFn is BUFSIZ so the last addressable spot it BUFSIZ-1.
		     * The loop increments by 2. So this must check for BUFSIZ-3. */
		    if (c >=BUFSIZ-3)
			bb_error_msg_and_die("unique name not found");
		    /* Get some semi random stuff to try and make a
		     * random filename based (and in the same dir as)
		     * the input file... */
		    gettimeofday (&tv, NULL);
		    value += ((bb_uint64_t) tv.tv_usec << 16) ^ tv.tv_sec ^ getpid ();
		    tempFn[++c] = ((value%62) < 26)?(value%62)+97:
				   ((value%62) < 52)?(value%62)+39:
				    (value%62)-4;
		    tempFn[c+1] = '\0';
		    value /= 62;

		    if ((fd = open(tempFn, O_RDWR | O_CREAT | O_EXCL, 0600)) < 0 ) {
			continue;
		    }
		    out = fdopen(fd, "w+");
		    if (!out) {
			close(fd);
			remove(tempFn);
			continue;
		    }
		    break;
		}
	} else {
		in = stdin;
		out = stdout;
	}

	while ((c = fgetc(in)) != EOF) {
		if (c == '\r') {
			if ((ConvType == CT_UNIX2DOS) && (fn != NULL)) {
				/* file is already in DOS format so it is
				 * not necessary to touch it.  */
				remove(tempFn);
				if (fclose(in) < 0 || fclose(out) < 0) {
					bb_perror_nomsg();
					return -2;
				}
				return 0;
			}
			break;
		}
		if (c == '\n') {
			if ((ConvType == CT_DOS2UNIX) && (fn != NULL)) {
				/* file is already in DOS format so it is
				 * not necessary to touch it.  */
				remove(tempFn);
				if ((fclose(in) < 0) || (fclose(out) < 0)) {
					bb_perror_nomsg();
					return -2;
				}
				return 0;
			}
			if (ConvType == CT_UNIX2DOS) {
				fputc('\r', out);
			}
		}
		fputc(c, out);
	}
	while (c != EOF && (c = fgetc(in)) != EOF) {
		if (c == '\r')
			continue;
		if (c == '\n') {
			if (ConvType == CT_UNIX2DOS)
				fputc('\r', out);
			fputc('\n', out);
			continue;
		}
		fputc(c, out);
	}

	if (fn != NULL) {
	    if (fclose(in) < 0 || fclose(out) < 0) {
		bb_perror_nomsg();
		remove(tempFn);
		return -2;
	    }

	    /* Assume they are both on the same filesystem (which
	     * should be true since we put them into the same directory
	     * so we _should_ be ok, but you never know... */
	    if (rename(tempFn, fn) < 0) {
		bb_perror_msg("unable to rename '%s' as '%s'", tempFn, fn);
		return -1;
	    }
	}

	return 0;
}

int dos2unix_main(int argc, char *argv[])
{
	int ConvType;
	int o;

	/* See if we are supposed to be doing dos2unix or unix2dos */
	if (argv[0][0]=='d') {
	    ConvType = CT_DOS2UNIX;
	} else {
	    ConvType = CT_UNIX2DOS;
	}

	/* process parameters */
	o = bb_getopt_ulflags(argc, argv, "ud");

	/* Do the conversion requested by an argument else do the default
	 * conversion depending on our name.  */
	if (o)
		ConvType = o;

	if (optind < argc) {
		while(optind < argc)
			if ((o = convert(argv[optind++], ConvType)) < 0)
				break;
	}
	else
		o = convert(NULL, ConvType);

	return o;
}