lib/stat.c

   1 /* Work around platform bugs in stat.
   2    Copyright (C) 2009-2011 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17 /* written by Eric Blake */
  18
  19 /* If the user's config.h happens to include <sys/stat.h>, let it include only
  20    the system's <sys/stat.h> here, so that orig_stat doesn't recurse to
  21    rpl_stat.  */
  22 #define __need_system_sys_stat_h
  23 #include <config.h>
  24
  25 /* Get the original definition of stat.  It might be defined as a macro.  */
  26 #include <sys/types.h>
  27 #include <sys/stat.h>
  28 #undef __need_system_sys_stat_h
  29
  30 static inline int
  31 orig_stat (const char *filename, struct stat *buf)
  32 {
  33   return stat (filename, buf);
  34 }
  35
  36 /* Specification.  */
  37 #include <sys/stat.h>
  38
  39 #include <errno.h>
  40 #include <limits.h>
  41 #include <stdbool.h>
  42 #include <string.h>
  43 #include "dosname.h"
  44 #include "verify.h"
  45
  46 /* Store information about NAME into ST.  Work around bugs with
  47    trailing slashes.  Mingw has other bugs (such as st_ino always
  48    being 0 on success) which this wrapper does not work around.  But
  49    at least this implementation provides the ability to emulate fchdir
  50    correctly.  */
  51
  52 int
  53 rpl_stat (char const *name, struct stat *st)
  54 {
  55   int result = orig_stat (name, st);
  56 #if REPLACE_FUNC_STAT_FILE
  57   /* Solaris 9 mistakenly succeeds when given a non-directory with a
  58      trailing slash.  */
  59   if (result == 0 && !S_ISDIR (st->st_mode))
  60     {
  61       size_t len = strlen (name);
  62       if (ISSLASH (name[len - 1]))
  63         {
  64           errno = ENOTDIR;
  65           return -1;
  66         }
  67     }
  68 #endif /* REPLACE_FUNC_STAT_FILE */
  69 #if REPLACE_FUNC_STAT_DIR
  70   /* The only known systems where REPLACE_FUNC_STAT_DIR is needed also
  71      have a constant PATH_MAX.  */
  72 # ifndef PATH_MAX
  73 #  error "Please port this replacement to your platform"
  74 # endif
  75
  76   if (result == -1 && errno == ENOENT)
  77     {
  78       /* Due to mingw's oddities, there are some directories (like
  79          c:\) where stat() only succeeds with a trailing slash, and
  80          other directories (like c:\windows) where stat() only
  81          succeeds without a trailing slash.  But we want the two to be
  82          synonymous, since chdir() manages either style.  Likewise, Mingw also
  83          reports ENOENT for names longer than PATH_MAX, when we want
  84          ENAMETOOLONG, and for stat("file/"), when we want ENOTDIR.
  85          Fortunately, mingw PATH_MAX is small enough for stack
  86          allocation.  */
  87       char fixed_name[PATH_MAX + 1] = {0};
  88       size_t len = strlen (name);
  89       bool check_dir = false;
  90       verify (PATH_MAX <= 4096);
  91       if (PATH_MAX <= len)
  92         errno = ENAMETOOLONG;
  93       else if (len)
  94         {
  95           strcpy (fixed_name, name);
  96           if (ISSLASH (fixed_name[len - 1]))
  97             {
  98               check_dir = true;
  99               while (len && ISSLASH (fixed_name[len - 1]))
 100                 fixed_name[--len] = '\0';
 101               if (!len)
 102                 fixed_name[0] = '/';
 103             }
 104           else
 105             fixed_name[len++] = '/';
 106           result = orig_stat (fixed_name, st);
 107           if (result == 0 && check_dir && !S_ISDIR (st->st_mode))
 108             {
 109               result = -1;
 110               errno = ENOTDIR;
 111             }
 112         }
 113     }
 114 #endif /* REPLACE_FUNC_STAT_DIR */
 115   return result;
 116 }