usr/src/local/local.cmd/20b.c

/*
 * Copyright (c) 1986 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that this notice is preserved and that due credit is given
 * to the University of California at Berkeley. The name of the University
 * may not be used to endorse or promote products derived from this
 * software without specific prior written permission. This software
 * is provided ``as is'' without express or implied warranty.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1986 Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)20b.c       5.3 (Berkeley) %G%";
#endif /* not lint */

#include <stdio.h>

main(argc, argv)
        int argc;
        char **argv;
{
        register int bsize, cc, want;
        register char *base, *current;
        char *alloca();

        if (argc > 1) {
                bsize = atoi(argv[1]);
                if (bsize <= 0) {
                        fputs("20b: bad block size.\n", stderr);
                        exit(-1);
                }
        }
        base = alloca(bsize);
        for (cc = bsize; cc > 0;) {
                current = base;
                for (want = bsize; want > 0 && cc > 0; want -= cc) {
                        if ((cc = read(0, current, want)) < 0)
                                return(-1);
                        current += cc;
                }
                want = bsize - want;
                if (want && write(1, base, want) != want)
                        return(-1);
        }
        return(0);
}