external/ibm-public/postfix/dist/src/util/sane_rename.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      sane_rename 3
   6 /* SUMMARY
   7 /*      sanitize rename() error returns
   8 /* SYNOPSIS
   9 /*      #include <sane_fsops.h>
  10 /*
  11 /*      int     sane_rename(old, new)
  12 /*      const char *from;
  13 /*      const char *to;
  14 /* DESCRIPTION
  15 /*      sane_rename() implements the rename(2) system call, and works
  16 /*      around some errors that are possible with NFS file systems.
  17 /* LICENSE
  18 /* .ad
  19 /* .fi
  20 /*      The Secure Mailer license must be distributed with this software.
  21 /* AUTHOR(S)
  22 /*      Wietse Venema
  23 /*      IBM T.J. Watson Research
  24 /*      P.O. Box 704
  25 /*      Yorktown Heights, NY 10598, USA
  26 /*--*/
  27
  28 /* System library. */
  29
  30 #include "sys_defs.h"
  31 #include <sys/stat.h>
  32 #include <errno.h>
  33 #include <stdio.h>                      /* rename(2) syscall in stdio.h? */
  34
  35 /* Utility library. */
  36
  37 #include "msg.h"
  38 #include "sane_fsops.h"
  39
  40 /* sane_rename - sanitize rename() error returns */
  41
  42 int     sane_rename(const char *from, const char *to)
  43 {
  44     const char *myname = "sane_rename";
  45     int     saved_errno;
  46     struct stat st;
  47
  48     /*
  49      * Normal case: rename() succeeds.
  50      */
  51     if (rename(from, to) >= 0)
  52         return (0);
  53
  54     /*
  55      * Woops. Save errno, and see if the error is an NFS artefact. If it is,
  56      * pretend the error never happened.
  57      */
  58     saved_errno = errno;
  59     if (stat(from, &st) < 0 && stat(to, &st) >= 0) {
  60         msg_info("%s(%s,%s): worked around spurious NFS error",
  61                  myname, from, to);
  62         return (0);
  63     }
  64
  65     /*
  66      * Nope, it didn't. Restore errno and report the error.
  67      */
  68     errno = saved_errno;
  69     return (-1);
  70 }