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DEFINITIONS
This source file includes following definitions.
- copy
- main
1 /*
2 * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
3 * The President and Fellows of Harvard College.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <unistd.h>
31 #include <err.h>
32
33 /*
34 * cp - copy a file.
35 * Usage: cp oldfile newfile
36 */
37
38
39 /* Copy one file to another. */
40 static
41 void
42 copy(const char *from, const char *to)
43 {
44 int fromfd;
45 int tofd;
46 char buf[1024];
47 int len, wr, wrtot;
48
49 /*
50 * Open the files, and give up if they won't open
51 */
52 fromfd = open(from, O_RDONLY);
53 if (fromfd<0) {
54 err(1, "%s", from);
55 }
56 tofd = open(to, O_WRONLY|O_CREAT|O_TRUNC);
57 if (tofd<0) {
58 err(1, "%s", to);
59 }
60
61 /*
62 * As long as we get more than zero bytes, we haven't hit EOF.
63 * Zero means EOF. Less than zero means an error occurred.
64 * We may read less than we asked for, though, in various cases
65 * for various reasons.
66 */
67 while ((len = read(fromfd, buf, sizeof(buf)))>0) {
68 /*
69 * Likewise, we may actually write less than we attempted
70 * to. So loop until we're done.
71 */
72 wrtot = 0;
73 while (wrtot < len) {
74 wr = write(tofd, buf+wrtot, len-wrtot);
75 if (wr<0) {
76 err(1, "%s", to);
77 }
78 wrtot += wr;
79 }
80 }
81 /*
82 * If we got a read error, print it and exit.
83 */
84 if (len<0) {
85 err(1, "%s", from);
86 }
87
88 if (close(fromfd) < 0) {
89 err(1, "%s: close", from);
90 }
91
92 if (close(tofd) < 0) {
93 err(1, "%s: close", to);
94 }
95 }
96
97 int
98 main(int argc, char *argv[])
99 {
100 /*
101 * Just do it.
102 *
103 * We don't allow the Unix model where you can do
104 * cp file1 file2 file3 destination-directory
105 *
106 * although this would be pretty easy to add.
107 */
108 if (argc!=3) {
109 errx(1, "Usage: cp OLDFILE NEWFILE");
110 }
111 copy(argv[1], argv[2]);
112 return 0;
113 }