/* * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009 * The President and Fellows of Harvard College. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include <unistd.h> #include <err.h> /* * cp - copy a file. * Usage: cp oldfile newfile */ /* Copy one file to another. */ static void copy(const char *from, const char *to) { int fromfd; int tofd; char buf[1024]; int len, wr, wrtot; /* * Open the files, and give up if they won't open */ fromfd = open(from, O_RDONLY); if (fromfd<0) { err(1, "%s", from); } tofd = open(to, O_WRONLY|O_CREAT|O_TRUNC); if (tofd<0) { err(1, "%s", to); } /* * As long as we get more than zero bytes, we haven't hit EOF. * Zero means EOF. Less than zero means an error occurred. * We may read less than we asked for, though, in various cases * for various reasons. */ while ((len = read(fromfd, buf, sizeof(buf)))>0) { /* * Likewise, we may actually write less than we attempted * to. So loop until we're done. */ wrtot = 0; while (wrtot < len) { wr = write(tofd, buf+wrtot, len-wrtot); if (wr<0) { err(1, "%s", to); } wrtot += wr; } } /* * If we got a read error, print it and exit. */ if (len<0) { err(1, "%s", from); } if (close(fromfd) < 0) { err(1, "%s: close", from); } if (close(tofd) < 0) { err(1, "%s: close", to); } } int main(int argc, char *argv[]) { /* * Just do it. * * We don't allow the Unix model where you can do * cp file1 file2 file3 destination-directory * * although this would be pretty easy to add. */ if (argc!=3) { errx(1, "Usage: cp OLDFILE NEWFILE"); } copy(argv[1], argv[2]); return 0; }