src/renameat2.c

   1 /*
   2  * Copyright (c) 2014, Miklos Szeredi <mszeredi@suse.cz>
   3  * This file is published under GPL2+.
   4  *
   5  * This is a trivial wrapper around the renameat2 syscall.
   6  */
   7
   8 #include "global.h"
   9
  10 #ifndef HAVE_RENAMEAT2
  11 #include <sys/syscall.h>
  12
  13 #if !defined(SYS_renameat2) && defined(__x86_64__)
  14 #define SYS_renameat2 316
  15 #endif
  16
  17 #if !defined(SYS_renameat2) && defined(__i386__)
  18 #define SYS_renameat2 353
  19 #endif
  20
  21 static int renameat2(int dfd1, const char *path1,
  22                      int dfd2, const char *path2,
  23                      unsigned int flags)
  24 {
  25 #ifdef SYS_renameat2
  26         return syscall(SYS_renameat2, dfd1, path1, dfd2, path2, flags);
  27 #else
  28         errno = ENOSYS;
  29         return -1;
  30 #endif
  31 }
  32 #endif
  33
  34 #ifndef RENAME_NOREPLACE
  35 #define RENAME_NOREPLACE        (1 << 0)        /* Don't overwrite target */
  36 #endif
  37 #ifndef RENAME_EXCHANGE
  38 #define RENAME_EXCHANGE         (1 << 1)        /* Exchange source and dest */
  39 #endif
  40 #ifndef RENAME_WHITEOUT
  41 #define RENAME_WHITEOUT         (1 << 2)        /* Whiteout source */
  42 #endif
  43
  44 int main(int argc, char *argv[])
  45 {
  46         int ret;
  47         int c;
  48         const char *path1 = NULL;
  49         const char *path2 = NULL;
  50         unsigned int flags = 0;
  51         int test = 0;
  52
  53         for (c = 1; c < argc; c++) {
  54                 if (argv[c][0] == '-') {
  55                         switch (argv[c][1]) {
  56                         case 't':
  57                                 test = 1;
  58                                 break;
  59                         case 'n':
  60                                 flags |= RENAME_NOREPLACE;
  61                                 break;
  62                         case 'x':
  63                                 flags |= RENAME_EXCHANGE;
  64                                 break;
  65                         case 'w':
  66                                 flags |= RENAME_WHITEOUT;
  67                                 break;
  68                         default:
  69                                 goto usage;
  70                         }
  71                 } else if (!path1) {
  72                         path1 = argv[c];
  73                 } else if (!path2) {
  74                         path2 = argv[c];
  75                 } else {
  76                         goto usage;
  77                 }
  78         }
  79
  80         if (!test && (!path1 || !path2))
  81                 goto usage;
  82
  83         ret = renameat2(AT_FDCWD, path1, AT_FDCWD, path2, flags);
  84         if (ret == -1) {
  85                 if (test) {
  86                         if (errno == ENOSYS || errno == EINVAL)
  87                                 return 1;
  88                         else
  89                                 return 0;
  90                 }
  91                 /*
  92                  * Turn EEXIST into ENOTEMPTY.  E.g. XFS uses EEXIST, and that
  93                  * is also accepted by the standards.
  94                  *
  95                  * This applies only to plain rename and RENAME_WHITEOUT
  96                  */
  97                 if (errno == EEXIST && (!flags || (flags & RENAME_WHITEOUT)))
  98                         errno = ENOTEMPTY;
  99
 100                 perror("");
 101                 return 1;
 102         }
 103
 104         return 0;
 105
 106 usage:
 107         fprintf(stderr,
 108                 "usage: %s [-t] [-n|-x|-w] path1 path2\n"
 109                 "  -t  test\n"
 110                 "  -n  noreplace\n"
 111                 "  -x  exchange\n"
 112                 "  -w  whiteout\n", argv[0]);
 113
 114         return 1;
 115 }