+
−/* Emulate link on platforms that lack it, namely native Windows platforms.
+
−
+
−   Copyright (C) 2009-2012 Free Software Foundation, Inc.
+
−
+
−   This program is free software; you can redistribute it and/or modify
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−   it under the terms of the GNU General Public License as published by
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−   the Free Software Foundation; either version 2, or (at your option)
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−   any later version.
+
−
+
−   This program is distributed in the hope that it will be useful,
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−   but WITHOUT ANY WARRANTY; without even the implied warranty of
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−   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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−   GNU General Public License for more details.
+
−
+
−   You should have received a copy of the GNU General Public License
+
−   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
+
−
+
−#include <config.h>
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−
+
−#include <unistd.h>
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−
+
−#include <errno.h>
+
−#include <stdlib.h>
+
−#include <string.h>
+
−#include <sys/stat.h>
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−
+
−#if !HAVE_LINK
+
−# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
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−
+
−#  define WIN32_LEAN_AND_MEAN
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−#  include <windows.h>
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−
+
−/* CreateHardLink was introduced only in Windows 2000.  */
+
−typedef BOOL (WINAPI * CreateHardLinkFuncType) (LPCTSTR lpFileName,
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−                                                LPCTSTR lpExistingFileName,
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−                                                LPSECURITY_ATTRIBUTES lpSecurityAttributes);
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−static CreateHardLinkFuncType CreateHardLinkFunc = NULL;
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−static BOOL initialized = FALSE;
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−
+
−static void
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−initialize (void)
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−{
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−  HMODULE kernel32 = GetModuleHandle ("kernel32.dll");
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−  if (kernel32 != NULL)
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−    {
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−      CreateHardLinkFunc =
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−        (CreateHardLinkFuncType) GetProcAddress (kernel32, "CreateHardLinkA");
+
−    }
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−  initialized = TRUE;
+
−}
+
−
+
−int
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−link (const char *file1, const char *file2)
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−{
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−  char *dir;
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−  size_t len1 = strlen (file1);
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−  size_t len2 = strlen (file2);
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−  if (!initialized)
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−    initialize ();
+
−  if (CreateHardLinkFunc == NULL)
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−    {
+
−      /* System does not support hard links.  */
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−      errno = EPERM;
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−      return -1;
+
−    }
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−  /* Reject trailing slashes on non-directories; mingw does not
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−     support hard-linking directories.  */
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−  if ((len1 && (file1[len1 - 1] == '/' || file1[len1 - 1] == '\\'))
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−      || (len2 && (file2[len2 - 1] == '/' || file2[len2 - 1] == '\\')))
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−    {
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−      struct stat st;
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−      if (stat (file1, &st) == 0 && S_ISDIR (st.st_mode))
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−        errno = EPERM;
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−      else
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−        errno = ENOTDIR;
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−      return -1;
+
−    }
+
−  /* CreateHardLink("b/.","a",NULL) creates file "b", so we must check
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−     that dirname(file2) exists.  */
+
−  dir = strdup (file2);
+
−  if (!dir)
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−    return -1;
+
−  {
+
−    struct stat st;
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−    char *p = strchr (dir, '\0');
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−    while (dir < p && (*--p != '/' && *p != '\\'));
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−    *p = '\0';
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−    if (p != dir && stat (dir, &st) == -1)
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−      {
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−        int saved_errno = errno;
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−        free (dir);
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−        errno = saved_errno;
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−        return -1;
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−      }
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−    free (dir);
+
−  }
+
−  /* Now create the link.  */
+
−  if (CreateHardLinkFunc (file2, file1, NULL) == 0)
+
−    {
+
−      /* It is not documented which errors CreateHardLink() can produce.
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−       * The following conversions are based on tests on a Windows XP SP2
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−       * system. */
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−      DWORD err = GetLastError ();
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−      switch (err)
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−        {
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−        case ERROR_ACCESS_DENIED:
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−          errno = EACCES;
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−          break;
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−
+
−        case ERROR_INVALID_FUNCTION:    /* fs does not support hard links */
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−          errno = EPERM;
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−          break;
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−
+
−        case ERROR_NOT_SAME_DEVICE:
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−          errno = EXDEV;
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−          break;
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−
+
−        case ERROR_PATH_NOT_FOUND:
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−        case ERROR_FILE_NOT_FOUND:
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−          errno = ENOENT;
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−          break;
+
−
+
−        case ERROR_INVALID_PARAMETER:
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−          errno = ENAMETOOLONG;
+
−          break;
+
−
+
−        case ERROR_TOO_MANY_LINKS:
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−          errno = EMLINK;
+
−          break;
+
−
+
−        case ERROR_ALREADY_EXISTS:
+
−          errno = EEXIST;
+
−          break;
+
−
+
−        default:
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−          errno = EIO;
+
−        }
+
−      return -1;
+
−    }
+
−
+
−  return 0;
+
−}
+
−
+
−# else /* !Windows */
+
−
+
−#  error "This platform lacks a link function, and Gnulib doesn't provide a replacement. This is a bug in Gnulib."
+
−
+
−# endif /* !Windows */
+
−#else /* HAVE_LINK */
+
−
+
−# undef link
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−
+
−/* Create a hard link from FILE1 to FILE2, working around platform bugs.  */
+
−int
+
−rpl_link (char const *file1, char const *file2)
+
−{
+
−  size_t len1;
+
−  size_t len2;
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−  struct stat st;
+
−
+
−  /* Don't allow IRIX to dereference dangling file2 symlink.  */
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−  if (!lstat (file2, &st))
+
−    {
+
−      errno = EEXIST;
+
−      return -1;
+
−    }
+
−
+
−  /* Reject trailing slashes on non-directories.  */
+
−  len1 = strlen (file1);
+
−  len2 = strlen (file2);
+
−  if ((len1 && file1[len1 - 1] == '/')
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−      || (len2 && file2[len2 - 1] == '/'))
+
−    {
+
−      /* Let link() decide whether hard-linking directories is legal.
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−         If stat() fails, then link() should fail for the same reason
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−         (although on Solaris 9, link("file/","oops") mistakenly
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−         succeeds); if stat() succeeds, require a directory.  */
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−      if (stat (file1, &st))
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−        return -1;
+
−      if (!S_ISDIR (st.st_mode))
+
−        {
+
−          errno = ENOTDIR;
+
−          return -1;
+
−        }
+
−    }
+
−  else
+
−    {
+
−      /* Fix Cygwin 1.5.x bug where link("a","b/.") creates file "b".  */
+
−      char *dir = strdup (file2);
+
−      char *p;
+
−      if (!dir)
+
−        return -1;
+
−      /* We already know file2 does not end in slash.  Strip off the
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−         basename, then check that the dirname exists.  */
+
−      p = strrchr (dir, '/');
+
−      if (p)
+
−        {
+
−          *p = '\0';
+
−          if (stat (dir, &st) == -1)
+
−            {
+
−              int saved_errno = errno;
+
−              free (dir);
+
−              errno = saved_errno;
+
−              return -1;
+
−            }
+
−        }
+
−      free (dir);
+
−    }
+
−  return link (file1, file2);
+
−}
+
−#endif /* HAVE_LINK */