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