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
  22 extern int errno;
  23 #endif
  24
  25 /* Rename file FROM to file TO.
  26    Return 0 if successful, -1 if not. */
  27
  28 int
  29 rename (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 }