1  /* Work around a bug of lstat on some systems
       2  
       3     Copyright (C) 1997-2006, 2008-2023 Free Software Foundation, Inc.
       4  
       5     This file is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU Lesser General Public License as
       7     published by the Free Software Foundation; either version 2.1 of the
       8     License, or (at your option) any later version.
       9  
      10     This file is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13     GNU Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public License
      16     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      17  
      18  /* written by Jim Meyering */
      19  
      20  /* If the user's config.h happens to include <sys/stat.h>, let it include only
      21     the system's <sys/stat.h> here, so that orig_lstat doesn't recurse to
      22     rpl_lstat.  */
      23  #define __need_system_sys_stat_h
      24  #include <config.h>
      25  
      26  #if !HAVE_LSTAT
      27  /* On systems that lack symlinks, our replacement <sys/stat.h> already
      28     defined lstat as stat, so there is nothing further to do other than
      29     avoid an empty file.  */
      30  typedef int dummy;
      31  #else /* HAVE_LSTAT */
      32  
      33  /* Get the original definition of lstat.  It might be defined as a macro.  */
      34  # include <sys/types.h>
      35  # include <sys/stat.h>
      36  # undef __need_system_sys_stat_h
      37  
      38  static int
      39  orig_lstat (const char *filename, struct stat *buf)
      40  {
      41    return lstat (filename, buf);
      42  }
      43  
      44  /* Specification.  */
      45  # ifdef __osf__
      46  /* Write "sys/stat.h" here, not <sys/stat.h>, otherwise OSF/1 5.1 DTK cc
      47     eliminates this include because of the preliminary #include <sys/stat.h>
      48     above.  */
      49  #  include "sys/stat.h"
      50  # else
      51  #  include <sys/stat.h>
      52  # endif
      53  
      54  # include "stat-time.h"
      55  
      56  # include <string.h>
      57  # include <errno.h>
      58  
      59  /* lstat works differently on Linux and Solaris systems.  POSIX (see
      60     "pathname resolution" in the glossary) requires that programs like
      61     'ls' take into consideration the fact that FILE has a trailing slash
      62     when FILE is a symbolic link.  On Linux and Solaris 10 systems, the
      63     lstat function already has the desired semantics (in treating
      64     'lstat ("symlink/", sbuf)' just like 'lstat ("symlink/.", sbuf)',
      65     but on Solaris 9 and earlier it does not.
      66  
      67     If FILE has a trailing slash and specifies a symbolic link,
      68     then use stat() to get more info on the referent of FILE.
      69     If the referent is a non-directory, then set errno to ENOTDIR
      70     and return -1.  Otherwise, return stat's result.  */
      71  
      72  int
      73  rpl_lstat (const char *file, struct stat *sbuf)
      74  {
      75    int result = orig_lstat (file, sbuf);
      76  
      77    /* This replacement file can blindly check against '/' rather than
      78       using the ISSLASH macro, because all platforms with '\\' either
      79       lack symlinks (mingw) or have working lstat (cygwin) and thus do
      80       not compile this file.  0 len should have already been filtered
      81       out above, with a failure return of ENOENT.  */
      82    if (result == 0)
      83      {
      84        if (S_ISDIR (sbuf->st_mode) || file[strlen (file) - 1] != '/')
      85          result = stat_time_normalize (result, sbuf);
      86        else
      87          {
      88            /* At this point, a trailing slash is permitted only on
      89               symlink-to-dir; but it should have found information on the
      90               directory, not the symlink.  Call 'stat' to get info about the
      91               link's referent.  Our replacement stat guarantees valid results,
      92               even if the symlink is not pointing to a directory.  */
      93            if (!S_ISLNK (sbuf->st_mode))
      94              {
      95                errno = ENOTDIR;
      96                return -1;
      97              }
      98            result = stat (file, sbuf);
      99          }
     100      }
     101    return result;
     102  }
     103  
     104  #endif /* HAVE_LSTAT */