gdb/gnulib/import/m4/getcwd-abort-bug.m4

   1 # serial 9
   2 # Determine whether getcwd aborts when the length of the working directory
   3 # name is unusually large.  Any length between 4k and 16k trigger the bug
   4 # when using glibc-2.4.90-9 or older.
   5
   6 # Copyright (C) 2006, 2009-2018 Free Software Foundation, Inc.
   7 # This file is free software; the Free Software Foundation
   8 # gives unlimited permission to copy and/or distribute it,
   9 # with or without modifications, as long as this notice is preserved.
  10
  11 # From Jim Meyering
  12
  13 # gl_FUNC_GETCWD_ABORT_BUG([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
  14 AC_DEFUN([gl_FUNC_GETCWD_ABORT_BUG],
  15 [
  16   AC_CHECK_DECLS_ONCE([getcwd])
  17   AC_CHECK_HEADERS_ONCE([unistd.h])
  18   AC_REQUIRE([gl_PATHMAX_SNIPPET_PREREQ])
  19
  20   gl_CHECK_FUNC_GETPAGESIZE
  21   if test $gl_cv_func_getpagesize = yes; then
  22     AC_DEFINE_UNQUOTED([HAVE_GETPAGESIZE], [1],
  23       [Define to 1 if the system has the 'getpagesize' function.])
  24   fi
  25
  26   AC_CACHE_CHECK([whether getcwd aborts when 4k < cwd_length < 16k],
  27     [gl_cv_func_getcwd_abort_bug],
  28     [# Remove any remnants of a previous test.
  29      rm -rf confdir-14B---
  30      # Arrange for deletion of the temporary directory this test creates.
  31      ac_clean_files="$ac_clean_files confdir-14B---"
  32      dnl Please keep this in sync with tests/test-getcwd.c.
  33      AC_RUN_IFELSE(
  34        [AC_LANG_SOURCE(
  35           [[
  36 #include <errno.h>
  37 #include <stdlib.h>
  38 #if HAVE_UNISTD_H
  39 # include <unistd.h>
  40 #else /* on Windows with MSVC */
  41 # include <direct.h>
  42 #endif
  43 #include <string.h>
  44 #include <sys/stat.h>
  45
  46 ]gl_PATHMAX_SNIPPET[
  47
  48 /* Don't get link errors because mkdir is redefined to rpl_mkdir.  */
  49 #undef mkdir
  50
  51 #ifndef S_IRWXU
  52 # define S_IRWXU 0700
  53 #endif
  54
  55 /* FIXME: skip the run-test altogether on systems without getpagesize.  */
  56 #if ! HAVE_GETPAGESIZE
  57 # define getpagesize() 0
  58 #endif
  59
  60 /* This size is chosen to be larger than PATH_MAX (4k), yet smaller than
  61    the 16kB pagesize on ia64 linux.  Those conditions make the code below
  62    trigger a bug in glibc's getcwd implementation before 2.4.90-10.  */
  63 #define TARGET_LEN (5 * 1024)
  64
  65 int
  66 main ()
  67 {
  68   char *cwd;
  69   size_t initial_cwd_len;
  70   int fail = 0;
  71
  72   /* The bug is triggered when PATH_MAX < getpagesize (), so skip
  73      this relatively expensive and invasive test if that's not true.  */
  74 #ifdef PATH_MAX
  75   int bug_possible = PATH_MAX < getpagesize ();
  76 #else
  77   int bug_possible = 0;
  78 #endif
  79   if (! bug_possible)
  80     return 0;
  81
  82   cwd = getcwd (NULL, 0);
  83   if (cwd == NULL)
  84     return 2;
  85
  86   initial_cwd_len = strlen (cwd);
  87   free (cwd);
  88
  89   if (1)
  90     {
  91       static char const dir_name[] = "confdir-14B---";
  92       size_t desired_depth = ((TARGET_LEN - 1 - initial_cwd_len)
  93                               / sizeof dir_name);
  94       size_t d;
  95       for (d = 0; d < desired_depth; d++)
  96         {
  97           if (mkdir (dir_name, S_IRWXU) < 0 || chdir (dir_name) < 0)
  98             {
  99               if (! (errno == ERANGE || errno == ENAMETOOLONG
 100                      || errno == ENOENT))
 101                 fail = 3; /* Unable to construct deep hierarchy.  */
 102               break;
 103             }
 104         }
 105
 106       /* If libc has the bug in question, this invocation of getcwd
 107          results in a failed assertion.  */
 108       cwd = getcwd (NULL, 0);
 109       if (cwd == NULL)
 110         fail = 4; /* getcwd didn't assert, but it failed for a long name
 111                      where the answer could have been learned.  */
 112       free (cwd);
 113
 114       /* Call rmdir first, in case the above chdir failed.  */
 115       rmdir (dir_name);
 116       while (0 < d--)
 117         {
 118           if (chdir ("..") < 0)
 119             {
 120               fail = 5;
 121               break;
 122             }
 123           rmdir (dir_name);
 124         }
 125     }
 126
 127   return fail;
 128 }
 129           ]])],
 130        [gl_cv_func_getcwd_abort_bug=no],
 131        [dnl An abort will provoke an exit code of something like 134 (128 + 6).
 132         dnl An exit code of 4 can also occur (in OpenBSD 4.9, NetBSD 5.1 for
 133         dnl example): getcwd (NULL, 0) fails rather than returning a string
 134         dnl longer than PATH_MAX.  This may be POSIX compliant (in some
 135         dnl interpretations of POSIX).  But gnulib's getcwd module wants to
 136         dnl provide a non-NULL value in this case.
 137         ret=$?
 138         if test $ret -ge 128 || test $ret = 4; then
 139           gl_cv_func_getcwd_abort_bug=yes
 140         else
 141           gl_cv_func_getcwd_abort_bug=no
 142         fi],
 143        [gl_cv_func_getcwd_abort_bug=yes])
 144     ])
 145   AS_IF([test $gl_cv_func_getcwd_abort_bug = yes], [$1], [$2])
 146 ])