u-tools/apps/tar/gnu/unlinkat.c

   1 /* -*- buffer-read-only: t -*- vi: set ro: */
   2 /* DO NOT EDIT! GENERATED AUTOMATICALLY! */
   3 /* Work around unlinkat bugs on Solaris 9.
   4
   5    Copyright (C) 2009-2011 Free Software Foundation, Inc.
   6
   7    This program is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 /* Written by Eric Blake.  */
  21
  22 #include <config.h>
  23
  24 #include <unistd.h>
  25
  26 #include <errno.h>
  27 #include <fcntl.h>
  28 #include <string.h>
  29 #include <sys/stat.h>
  30
  31 #include "dosname.h"
  32 #include "openat.h"
  33
  34 #if HAVE_UNLINKAT
  35
  36 # undef unlinkat
  37
  38 /* unlinkat without AT_REMOVEDIR does not honor trailing / on Solaris
  39    9.  Solve it in a similar manner to unlink.  */
  40
  41 int
  42 rpl_unlinkat (int fd, char const *name, int flag)
  43 {
  44   size_t len;
  45   int result = 0;
  46   /* rmdir behavior has no problems with trailing slash.  */
  47   if (flag & AT_REMOVEDIR)
  48     return unlinkat (fd, name, flag);
  49
  50   len = strlen (name);
  51   if (len && ISSLASH (name[len - 1]))
  52     {
  53       /* See the lengthy comment in unlink.c why we disobey the POSIX
  54          rule of letting unlink("link-to-dir/") attempt to unlink a
  55          directory.  */
  56       struct stat st;
  57       result = lstatat (fd, name, &st);
  58       if (result == 0)
  59         {
  60           /* Trailing NUL will overwrite the trailing slash.  */
  61           char *short_name = malloc (len);
  62           if (!short_name)
  63             {
  64               errno = EPERM;
  65               return -1;
  66             }
  67           memcpy (short_name, name, len);
  68           while (len && ISSLASH (short_name[len - 1]))
  69             short_name[--len] = '\0';
  70           if (len && (lstatat (fd, short_name, &st) || S_ISLNK (st.st_mode)))
  71             {
  72               free (short_name);
  73               errno = EPERM;
  74               return -1;
  75             }
  76           free (short_name);
  77         }
  78     }
  79   if (!result)
  80     result = unlinkat (fd, name, flag);
  81   return result;
  82 }
  83
  84 #else /* !HAVE_UNLINKAT */
  85
  86 /* Replacement for Solaris' function by the same name.
  87    <http://www.google.com/search?q=unlinkat+site:docs.sun.com>
  88    First, try to simulate it via (unlink|rmdir) ("/proc/self/fd/FD/FILE").
  89    Failing that, simulate it via save_cwd/fchdir/(unlink|rmdir)/restore_cwd.
  90    If either the save_cwd or the restore_cwd fails (relatively unlikely),
  91    then give a diagnostic and exit nonzero.
  92    Otherwise, this function works just like Solaris' unlinkat.  */
  93
  94 # define AT_FUNC_NAME unlinkat
  95 # define AT_FUNC_F1 rmdir
  96 # define AT_FUNC_F2 unlink
  97 # define AT_FUNC_USE_F1_COND AT_REMOVEDIR
  98 # define AT_FUNC_POST_FILE_PARAM_DECLS , int flag
  99 # define AT_FUNC_POST_FILE_ARGS        /* empty */
 100 # include "at-func.c"
 101 # undef AT_FUNC_NAME
 102 # undef AT_FUNC_F1
 103 # undef AT_FUNC_F2
 104 # undef AT_FUNC_USE_F1_COND
 105 # undef AT_FUNC_POST_FILE_PARAM_DECLS
 106 # undef AT_FUNC_POST_FILE_ARGS
 107
 108 #endif /* !HAVE_UNLINKAT */