1 /* rename.c -- rename a file, preserving symlinks.
2 Copyright 1999, 2002, 2003 Free Software Foundation, Inc.
3
4 This file is part of GNU Binutils.
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
19 02111-1307, USA. */
20
21 #include "bfd.h"
22 #include "bucomm.h"
23
24 #include <sys/stat.h>
25
26 #ifdef HAVE_GOOD_UTIME_H
27 #include <utime.h>
28 #else /* ! HAVE_GOOD_UTIME_H */
29 #ifdef HAVE_UTIMES
30 #include <sys/time.h>
31 #endif /* HAVE_UTIMES */
32 #endif /* ! HAVE_GOOD_UTIME_H */
33
34 /* We need to open the file in binary modes on system where that makes
35 a difference. */
36 #ifndef O_BINARY
37 #define O_BINARY 0
38 #endif
39
40 static int simple_copy (const char *, const char *);
41
42 /* The number of bytes to copy at once. */
43 #define COPY_BUF 8192
44
45 /* Copy file FROM to file TO, performing no translations.
46 Return 0 if ok, -1 if error. */
47
48 static int
simple_copy(const char * from,const char * to)49 simple_copy (const char *from, const char *to)
50 {
51 int fromfd, tofd, nread;
52 int saved;
53 char buf[COPY_BUF];
54
55 fromfd = open (from, O_RDONLY | O_BINARY);
56 if (fromfd < 0)
57 return -1;
58 #ifdef O_CREAT
59 tofd = open (to, O_CREAT | O_WRONLY | O_TRUNC | O_BINARY, 0777);
60 #else
61 tofd = creat (to, 0777);
62 #endif
63 if (tofd < 0)
64 {
65 saved = errno;
66 close (fromfd);
67 errno = saved;
68 return -1;
69 }
70 while ((nread = read (fromfd, buf, sizeof buf)) > 0)
71 {
72 if (write (tofd, buf, nread) != nread)
73 {
74 saved = errno;
75 close (fromfd);
76 close (tofd);
77 errno = saved;
78 return -1;
79 }
80 }
81 saved = errno;
82 close (fromfd);
83 close (tofd);
84 if (nread < 0)
85 {
86 errno = saved;
87 return -1;
88 }
89 return 0;
90 }
91
92 /* Set the times of the file DESTINATION to be the same as those in
93 STATBUF. */
94
95 void
set_times(const char * destination,const struct stat * statbuf)96 set_times (const char *destination, const struct stat *statbuf)
97 {
98 int result;
99
100 {
101 #ifdef HAVE_GOOD_UTIME_H
102 struct utimbuf tb;
103
104 tb.actime = statbuf->st_atime;
105 tb.modtime = statbuf->st_mtime;
106 result = utime (destination, &tb);
107 #else /* ! HAVE_GOOD_UTIME_H */
108 #ifndef HAVE_UTIMES
109 long tb[2];
110
111 tb[0] = statbuf->st_atime;
112 tb[1] = statbuf->st_mtime;
113 result = utime (destination, tb);
114 #else /* HAVE_UTIMES */
115 struct timeval tv[2];
116
117 tv[0].tv_sec = statbuf->st_atime;
118 tv[0].tv_usec = 0;
119 tv[1].tv_sec = statbuf->st_mtime;
120 tv[1].tv_usec = 0;
121 result = utimes (destination, tv);
122 #endif /* HAVE_UTIMES */
123 #endif /* ! HAVE_GOOD_UTIME_H */
124 }
125
126 if (result != 0)
127 non_fatal (_("%s: cannot set time: %s"), destination, strerror (errno));
128 }
129
130 #ifndef S_ISLNK
131 #ifdef S_IFLNK
132 #define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
133 #else
134 #define S_ISLNK(m) 0
135 #define lstat stat
136 #endif
137 #endif
138
139 /* Rename FROM to TO, copying if TO is a link.
140 Return 0 if ok, -1 if error. */
141
142 int
smart_rename(const char * from,const char * to,int preserve_dates)143 smart_rename (const char *from, const char *to, int preserve_dates)
144 {
145 bfd_boolean exists;
146 struct stat s;
147 int ret = 0;
148
149 exists = lstat (to, &s) == 0;
150
151 #if defined (_WIN32) && !defined (__CYGWIN32__)
152 /* Win32, unlike unix, will not erase `to' in `rename(from, to)' but
153 fail instead. Also, chown is not present. */
154
155 if (exists)
156 remove (to);
157
158 ret = rename (from, to);
159 if (ret != 0)
160 {
161 /* We have to clean up here. */
162 non_fatal (_("unable to rename '%s' reason: %s"), to, strerror (errno));
163 unlink (from);
164 }
165 #else
166 /* Use rename only if TO is not a symbolic link and has
167 only one hard link, and we have permission to write to it. */
168 if (! exists
169 || (!S_ISLNK (s.st_mode)
170 && S_ISREG (s.st_mode)
171 && (s.st_mode & S_IWUSR)
172 && s.st_nlink == 1)
173 )
174 {
175 ret = rename (from, to);
176 if (ret == 0)
177 {
178 if (exists)
179 {
180 /* Try to preserve the permission bits and ownership of
181 TO. First get the mode right except for the setuid
182 bit. Then change the ownership. Then fix the setuid
183 bit. We do the chmod before the chown because if the
184 chown succeeds, and we are a normal user, we won't be
185 able to do the chmod afterward. We don't bother to
186 fix the setuid bit first because that might introduce
187 a fleeting security problem, and because the chown
188 will clear the setuid bit anyhow. We only fix the
189 setuid bit if the chown succeeds, because we don't
190 want to introduce an unexpected setuid file owned by
191 the user running objcopy. */
192 chmod (to, s.st_mode & 0777);
193 if (chown (to, s.st_uid, s.st_gid) >= 0)
194 chmod (to, s.st_mode & 07777);
195 }
196 }
197 else
198 {
199 /* We have to clean up here. */
200 non_fatal (_("unable to rename '%s' reason: %s"), to, strerror (errno));
201 unlink (from);
202 }
203 }
204 else
205 {
206 ret = simple_copy (from, to);
207 if (ret != 0)
208 non_fatal (_("unable to copy file '%s' reason: %s"), to, strerror (errno));
209
210 if (preserve_dates)
211 set_times (to, &s);
212 unlink (from);
213 }
214 #endif /* _WIN32 && !__CYGWIN32__ */
215
216 return ret;
217 }
218