1 /* Copying of files.
2 Copyright (C) 2001-2003, 2006 Free Software Foundation, Inc.
3 Written by Bruno Haible <haible@clisp.cons.org>, 2001.
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2, or (at your option)
8 any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
18
19
20 #include <config.h>
21
22 /* Specification. */
23 #include "copy-file.h"
24
25 #include <errno.h>
26 #include <fcntl.h>
27 #include <stddef.h>
28 #include <sys/stat.h>
29 #include <unistd.h>
30
31 #if HAVE_UTIME || HAVE_UTIMES
32 # if HAVE_UTIME_H
33 # include <utime.h>
34 # else
35 # include <sys/utime.h>
36 # endif
37 #endif
38
39 #include "error.h"
40 #include "safe-read.h"
41 #include "full-write.h"
42 #include "binary-io.h"
43 #include "exit.h"
44 #include "gettext.h"
45
46 #define _(str) gettext (str)
47
48 void
copy_file_preserving(const char * src_filename,const char * dest_filename)49 copy_file_preserving (const char *src_filename, const char *dest_filename)
50 {
51 int src_fd;
52 struct stat statbuf;
53 int mode;
54 int dest_fd;
55 char buf[4096];
56 const size_t buf_size = sizeof (buf);
57
58 src_fd = open (src_filename, O_RDONLY | O_BINARY);
59 if (src_fd < 0 || fstat (src_fd, &statbuf) < 0)
60 error (EXIT_FAILURE, errno, _("error while opening \"%s\" for reading"),
61 src_filename);
62
63 mode = statbuf.st_mode & 07777;
64
65 dest_fd = open (dest_filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0600);
66 if (dest_fd < 0)
67 error (EXIT_FAILURE, errno, _("cannot open backup file \"%s\" for writing"),
68 dest_filename);
69
70 /* Copy the file contents. */
71 for (;;)
72 {
73 size_t n_read = safe_read (src_fd, buf, buf_size);
74 if (n_read == SAFE_READ_ERROR)
75 error (EXIT_FAILURE, errno, _("error reading \"%s\""), src_filename);
76 if (n_read == 0)
77 break;
78
79 if (full_write (dest_fd, buf, n_read) < n_read)
80 error (EXIT_FAILURE, errno, _("error writing \"%s\""), dest_filename);
81 }
82
83 if (close (dest_fd) < 0)
84 error (EXIT_FAILURE, errno, _("error writing \"%s\""), dest_filename);
85 if (close (src_fd) < 0)
86 error (EXIT_FAILURE, errno, _("error after reading \"%s\""), src_filename);
87
88 /* Preserve the access and modification times. */
89 #if HAVE_UTIME
90 {
91 struct utimbuf ut;
92
93 ut.actime = statbuf.st_atime;
94 ut.modtime = statbuf.st_mtime;
95 utime (dest_filename, &ut);
96 }
97 #elif HAVE_UTIMES
98 {
99 struct timeval ut[2];
100
101 ut[0].tv_sec = statbuf.st_atime; ut[0].tv_usec = 0;
102 ut[1].tv_sec = statbuf.st_mtime; ut[1].tv_usec = 0;
103 utimes (dest_filename, &ut);
104 }
105 #endif
106
107 #if HAVE_CHOWN
108 /* Preserve the owner and group. */
109 chown (dest_filename, statbuf.st_uid, statbuf.st_gid);
110 #endif
111
112 /* Preserve the access permissions. */
113 chmod (dest_filename, mode);
114 }
115