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 #include <config.h>
  20
  21 /* Get the original definition of stat.  It might be defined as a macro.  */
  22 #define __need_system_sys_stat_h
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #undef __need_system_sys_stat_h
  26
  27 static inline int
  28 orig_stat (const char *filename, struct stat *buf)
  29 {
  30   return stat (filename, buf);
  31 }
  32
  33 /* Specification.  */
  34 #include <sys/stat.h>
  35
  36 #include <errno.h>
  37 #include <limits.h>
  38 #include <stdbool.h>
  39 #include <string.h>
  40 #include "dosname.h"
  41 #include "verify.h"
  42
  43 /* Store information about NAME into ST.  Work around bugs with
  44    trailing slashes.  Mingw has other bugs (such as st_ino always
  45    being 0 on success) which this wrapper does not work around.  But
  46    at least this implementation provides the ability to emulate fchdir
  47    correctly.  */
  48
  49 int
  50 rpl_stat (char const *name, struct stat *st)
  51 {
  52   int result = orig_stat (name, st);
  53 #if REPLACE_FUNC_STAT_FILE
  54   /* Solaris 9 mistakenly succeeds when given a non-directory with a
  55      trailing slash.  */
  56   if (result == 0 && !S_ISDIR (st->st_mode))
  57     {
  58       size_t len = strlen (name);
  59       if (ISSLASH (name[len - 1]))
  60         {
  61           errno = ENOTDIR;
  62           return -1;
  63         }
  64     }
  65 #endif /* REPLACE_FUNC_STAT_FILE */
  66 #if REPLACE_FUNC_STAT_DIR
  67   /* The only known systems where REPLACE_FUNC_STAT_DIR is needed also
  68      have a constant PATH_MAX.  */
  69 # ifndef PATH_MAX
  70 #  error "Please port this replacement to your platform"
  71 # endif
  72
  73   if (result == -1 && errno == ENOENT)
  74     {
  75       /* Due to mingw's oddities, there are some directories (like
  76          c:\) where stat() only succeeds with a trailing slash, and
  77          other directories (like c:\windows) where stat() only
  78          succeeds without a trailing slash.  But we want the two to be
  79          synonymous, since chdir() manages either style.  Likewise, Mingw also
  80          reports ENOENT for names longer than PATH_MAX, when we want
  81          ENAMETOOLONG, and for stat("file/"), when we want ENOTDIR.
  82          Fortunately, mingw PATH_MAX is small enough for stack
  83          allocation.  */
  84       char fixed_name[PATH_MAX + 1] = {0};
  85       size_t len = strlen (name);
  86       bool check_dir = false;
  87       verify (PATH_MAX <= 4096);
  88       if (PATH_MAX <= len)
  89         errno = ENAMETOOLONG;
  90       else if (len)
  91         {
  92           strcpy (fixed_name, name);
  93           if (ISSLASH (fixed_name[len - 1]))
  94             {
  95               check_dir = true;
  96               while (len && ISSLASH (fixed_name[len - 1]))
  97                 fixed_name[--len] = '\0';
  98               if (!len)
  99                 fixed_name[0] = '/';
 100             }
 101           else
 102             fixed_name[len++] = '/';
 103           result = orig_stat (fixed_name, st);
 104           if (result == 0 && check_dir && !S_ISDIR (st->st_mode))
 105             {
 106               result = -1;
 107               errno = ENOTDIR;
 108             }
 109         }
 110     }
 111 #endif /* REPLACE_FUNC_STAT_DIR */
 112   return result;
 113 }