/contrib/cvs/lib/rename.c

 1/* rename.c -- BSD compatible directory function for System V
 2   Copyright (C) 1988, 1990 Free Software Foundation, Inc.
 3
 4   This program is free software; you can redistribute it and/or modify
 5   it under the terms of the GNU General Public License as published by
 6   the Free Software Foundation; either version 2, or (at your option)
 7   any later version.
 8
 9   This program is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12   GNU General Public License for more details.  */
13
14#ifdef HAVE_CONFIG_H
15#include "config.h"
16#endif
17
18#include <sys/types.h>
19#include <sys/stat.h>
20#include <errno.h>
21#ifndef STDC_HEADERS
22extern int errno;
23#endif
24
25/* Rename file FROM to file TO.
26   Return 0 if successful, -1 if not. */
27
28int
29rename (from, to)
30     char *from;
31     char *to;
32{
33  struct stat from_stats;
34  int pid, status;
35
36  if (stat (from, &from_stats) == 0)
37    {
38      /* We don't check existence_error because the systems which need it
39	 have rename().  */
40      if (CVS_UNLINK (to) && errno != ENOENT)
41	return -1;
42      if ((from_stats.st_mode & S_IFMT) == S_IFDIR)
43	{
44#ifdef MVDIR
45	  /* I don't think MVDIR ever gets defined, but I don't think
46	     it matters, because I don't think CVS ever calls rename()
47	     on directories.  */
48
49	  /* Need a setuid root process to link and unlink directories. */
50	  pid = fork ();
51	  switch (pid)
52	    {
53	    case -1:		/* Error. */
54	      error (1, errno, "cannot fork");
55
56	    case 0:		/* Child. */
57	      execl (MVDIR, "mvdir", from, to, (char *) 0);
58	      error (255, errno, "cannot run `%s'", MVDIR);
59
60	    default:		/* Parent. */
61	      while (wait (&status) != pid)
62		/* Do nothing. */ ;
63
64	      errno = 0;	/* mvdir printed the system error message. */
65	      return status != 0 ? -1 : 0;
66	    }
67#else /* no MVDIR */
68	  error (1, 0, "internal error: cannot move directories");
69#endif /* no MVDIR */
70	}
71      else
72	{
73	  /* We don't check existence_error because the systems which need it
74	     have rename().  */
75	  if (link (from, to) == 0 && (CVS_UNLINK (from) == 0 || errno == ENOENT))
76	    return 0;
77	}
78    }
79  return -1;
80}