lib/stat.c

   1 /* Work around platform bugs in stat.
   2    Copyright (C) 2009-2012 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 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
  31 # if _GL_WINDOWS_64_BIT_ST_SIZE
  32 #  define stat _stati64
  33 #  define REPLACE_FUNC_STAT_DIR 1
  34 #  undef REPLACE_FUNC_STAT_FILE
  35 # elif REPLACE_FUNC_STAT_FILE
  36 /* mingw64 has a broken stat() function, based on _stat(), in libmingwex.a.
  37    Bypass it.  */
  38 #  define stat _stat
  39 #  define REPLACE_FUNC_STAT_DIR 1
  40 #  undef REPLACE_FUNC_STAT_FILE
  41 # endif
  42 #endif
  43
  44 static inline int
  45 orig_stat (const char *filename, struct stat *buf)
  46 {
  47   return stat (filename, buf);
  48 }
  49
  50 /* Specification.  */
  51 /* Write "sys/stat.h" here, not <sys/stat.h>, otherwise OSF/1 5.1 DTK cc
  52    eliminates this include because of the preliminary #include <sys/stat.h>
  53    above.  */
  54 #include "sys/stat.h"
  55
  56 #include <errno.h>
  57 #include <limits.h>
  58 #include <stdbool.h>
  59 #include <string.h>
  60 #include "dosname.h"
  61 #include "verify.h"
  62
  63 #if REPLACE_FUNC_STAT_DIR
  64 # include "pathmax.h"
  65   /* The only known systems where REPLACE_FUNC_STAT_DIR is needed also
  66      have a constant PATH_MAX.  */
  67 # ifndef PATH_MAX
  68 #  error "Please port this replacement to your platform"
  69 # endif
  70 #endif
  71
  72 /* Store information about NAME into ST.  Work around bugs with
  73    trailing slashes.  Mingw has other bugs (such as st_ino always
  74    being 0 on success) which this wrapper does not work around.  But
  75    at least this implementation provides the ability to emulate fchdir
  76    correctly.  */
  77
  78 int
  79 rpl_stat (char const *name, struct stat *st)
  80 {
  81   int result = orig_stat (name, st);
  82 #if REPLACE_FUNC_STAT_FILE
  83   /* Solaris 9 mistakenly succeeds when given a non-directory with a
  84      trailing slash.  */
  85   if (result == 0 && !S_ISDIR (st->st_mode))
  86     {
  87       size_t len = strlen (name);
  88       if (ISSLASH (name[len - 1]))
  89         {
  90           errno = ENOTDIR;
  91           return -1;
  92         }
  93     }
  94 #endif /* REPLACE_FUNC_STAT_FILE */
  95 #if REPLACE_FUNC_STAT_DIR
  96
  97   if (result == -1 && errno == ENOENT)
  98     {
  99       /* Due to mingw's oddities, there are some directories (like
 100          c:\) where stat() only succeeds with a trailing slash, and
 101          other directories (like c:\windows) where stat() only
 102          succeeds without a trailing slash.  But we want the two to be
 103          synonymous, since chdir() manages either style.  Likewise, Mingw also
 104          reports ENOENT for names longer than PATH_MAX, when we want
 105          ENAMETOOLONG, and for stat("file/"), when we want ENOTDIR.
 106          Fortunately, mingw PATH_MAX is small enough for stack
 107          allocation.  */
 108       char fixed_name[PATH_MAX + 1] = {0};
 109       size_t len = strlen (name);
 110       bool check_dir = false;
 111       verify (PATH_MAX <= 4096);
 112       if (PATH_MAX <= len)
 113         errno = ENAMETOOLONG;
 114       else if (len)
 115         {
 116           strcpy (fixed_name, name);
 117           if (ISSLASH (fixed_name[len - 1]))
 118             {
 119               check_dir = true;
 120               while (len && ISSLASH (fixed_name[len - 1]))
 121                 fixed_name[--len] = '\0';
 122               if (!len)
 123                 fixed_name[0] = '/';
 124             }
 125           else
 126             fixed_name[len++] = '/';
 127           result = orig_stat (fixed_name, st);
 128           if (result == 0 && check_dir && !S_ISDIR (st->st_mode))
 129             {
 130               result = -1;
 131               errno = ENOTDIR;
 132             }
 133         }
 134     }
 135 #endif /* REPLACE_FUNC_STAT_DIR */
 136   return result;
 137 }