IABSD.fr/src/usr.bin/rsync/copy.c

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• Author : jmc
  Date : 2022-12-26 19:16:00
  Hash : d9a51c35
  Message : spelling fixes; from paul tagliamonte amendments to his diff are noted on tech

• usr.bin/rsync/copy.c

• /*	$OpenBSD: copy.c,v 1.4 2022/12/26 19:16:02 jmc Exp $ */
  /*
   * Copyright (c) 2021 Claudio Jeker <claudio@openbsd.org>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include <sys/types.h>
  
  #include <err.h>
  #include <fcntl.h>
  #include <unistd.h>
  
  #include "extern.h"
  
  #define _MAXBSIZE (64 * 1024)
  
  /*
   * Return true if all bytes in buffer are zero.
   * A buffer of zero length is also considered a zero buffer.
   */
  static int
  iszero(const void *b, size_t len)
  {
  	const unsigned char *c = b;
  
  	for (; len > 0; len--) {
  		if (*c++ != '\0')
  			return 0;
  	}
  	return 1;
  }
  
  static int
  copy_internal(int fromfd, int tofd)
  {
  	char buf[_MAXBSIZE];
  	ssize_t r, w;
  
  	while ((r = read(fromfd, buf, sizeof(buf))) > 0) {
  		if (iszero(buf, sizeof(buf))) {
  			if (lseek(tofd, r, SEEK_CUR) == -1)
  				return -1;
  		} else {
  			w = write(tofd, buf, r);
  			if (r != w || w == -1)
  				return -1;
  		}
  	}
  	if (r == -1)
  		return -1;
  	if (ftruncate(tofd, lseek(tofd, 0, SEEK_CUR)) == -1)
  		return -1;
  	return 0;
  }
  
  void
  copy_file(int rootfd, const char *basedir, const struct flist *f)
  {
  	int fromfd, tofd, dfd;
  
  	dfd = openat(rootfd, basedir, O_RDONLY | O_DIRECTORY);
  	if (dfd == -1)
  		err(ERR_FILE_IO, "%s: openat", basedir);
  
  	fromfd = openat(dfd, f->path, O_RDONLY | O_NOFOLLOW);
  	if (fromfd == -1)
  		err(ERR_FILE_IO, "%s/%s: openat", basedir, f->path);
  	close(dfd);
  
  	tofd = openat(rootfd, f->path,
  	    O_WRONLY | O_NOFOLLOW | O_TRUNC | O_CREAT | O_EXCL,
  	    0600);
  	if (tofd == -1)
  		err(ERR_FILE_IO, "%s: openat", f->path);
  
  	if (copy_internal(fromfd, tofd) == -1)
  		err(ERR_FILE_IO, "%s: copy file", f->path);
  
  	close(fromfd);
  	close(tofd);
  }