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 #if !defined(SYS_renameat2) && defined(__i386__)
  22 #define SYS_renameat2 353
  23 #endif
  24
  25 static int renameat2(int dfd1, const char *path1,
  26                      int dfd2, const char *path2,
  27                      unsigned int flags)
  28 {
  29 #ifdef SYS_renameat2
  30         return syscall(SYS_renameat2, dfd1, path1, dfd2, path2, flags);
  31 #else
  32         errno = ENOSYS;
  33         return -1;
  34 #endif
  35 }
  36 #endif
  37
  38 #ifndef RENAME_NOREPLACE
  39 #define RENAME_NOREPLACE        (1 << 0)        /* Don't overwrite target */
  40 #endif
  41 #ifndef RENAME_EXCHANGE
  42 #define RENAME_EXCHANGE         (1 << 1)        /* Exchange source and dest */
  43 #endif
  44 #ifndef RENAME_WHITEOUT
  45 #define RENAME_WHITEOUT         (1 << 2)        /* Whiteout source */
  46 #endif
  47
  48 int main(int argc, char *argv[])
  49 {
  50         int ret;
  51         int c;
  52         const char *path1 = NULL;
  53         const char *path2 = NULL;
  54         unsigned int flags = 0;
  55         int test = 0;
  56
  57         for (c = 1; c < argc; c++) {
  58                 if (argv[c][0] == '-') {
  59                         switch (argv[c][1]) {
  60                         case 't':
  61                                 test = 1;
  62                                 break;
  63                         case 'n':
  64                                 flags |= RENAME_NOREPLACE;
  65                                 break;
  66                         case 'x':
  67                                 flags |= RENAME_EXCHANGE;
  68                                 break;
  69                         case 'w':
  70                                 flags |= RENAME_WHITEOUT;
  71                                 break;
  72                         default:
  73                                 goto usage;
  74                         }
  75                 } else if (!path1) {
  76                         path1 = argv[c];
  77                 } else if (!path2) {
  78                         path2 = argv[c];
  79                 } else {
  80                         goto usage;
  81                 }
  82         }
  83
  84         if (!test && (!path1 || !path2))
  85                 goto usage;
  86
  87         ret = renameat2(AT_FDCWD, path1, AT_FDCWD, path2, flags);
  88         if (ret == -1) {
  89                 if (test) {
  90                         if (errno == ENOSYS || errno == EINVAL)
  91                                 return 1;
  92                         else
  93                                 return 0;
  94                 }
  95                 /*
  96                  * Turn EEXIST into ENOTEMPTY.  E.g. XFS uses EEXIST, and that
  97                  * is also accepted by the standards.
  98                  *
  99                  * This applies only to plain rename and RENAME_WHITEOUT
 100                  */
 101                 if (errno == EEXIST && (!flags || (flags & RENAME_WHITEOUT)))
 102                         errno = ENOTEMPTY;
 103
 104                 perror("");
 105                 return 1;
 106         }
 107
 108         return 0;
 109
 110 usage:
 111         fprintf(stderr,
 112                 "usage: %s [-t] [-n|-x|-w] path1 path2\n"
 113                 "  -t  test\n"
 114                 "  -n  noreplace\n"
 115                 "  -x  exchange\n"
 116                 "  -w  whiteout\n", argv[0]);
 117
 118         return 1;
 119 }