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
40static 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
48static int
49simple_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
95void
96set_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
142int
143smart_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 of TO. Don't
181	       * restore special bits. */
182	      chmod (to, s.st_mode & 0777);
183	    }
184	}
185      else
186	{
187	  /* We have to clean up here.  */
188	  non_fatal (_("unable to rename '%s' reason: %s"), to, strerror (errno));
189	  unlink (from);
190	}
191    }
192  else
193    {
194      ret = simple_copy (from, to);
195      if (ret != 0)
196	non_fatal (_("unable to copy file '%s' reason: %s"), to, strerror (errno));
197
198      if (preserve_dates)
199	set_times (to, &s);
200      unlink (from);
201    }
202#endif /* _WIN32 && !__CYGWIN32__ */
203
204  return ret;
205}
206