coreutils/m4/readdir.m4

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#serial 3
dnl SunOS's readdir is broken in such a way that rm.c has to add extra code
dnl to test whether a NULL return value really means there are no more files
dnl in the directory.
dnl
dnl Detect the problem by creating a directory containing 300 files (254 not
dnl counting . and .. is the minimum) and see if a loop doing `readdir; unlink'
dnl removes all of them.
dnl
dnl Define HAVE_WORKING_READDIR if readdir does *not* have this problem.
dnl Written by Jim Meyering.
AC_DEFUN(jm_FUNC_READDIR,
[dnl
AC_REQUIRE([AC_HEADER_DIRENT])
AC_CHECK_HEADERS(string.h)
AC_CACHE_CHECK([for working readdir], jm_cv_func_working_readdir,
[dnl
# Arrange for deletion of the temporary directory this test creates, in
# case the test itself fails to delete everything -- as happens on Sunos.
ac_clean_files="$ac_clean_files conf-dir"
AC_TRY_RUN(
[# include <stdio.h>
# include <sys/types.h>
# if HAVE_STRING_H
# include <string.h>
# endif
# ifdef HAVE_DIRENT_H
# include <dirent.h>
# define NLENGTH(direct) (strlen((direct)->d_name))
# else /* not HAVE_DIRENT_H */
# define dirent direct
# define NLENGTH(direct) ((direct)->d_namlen)
# ifdef HAVE_SYS_NDIR_H
# include <sys/ndir.h>
# endif /* HAVE_SYS_NDIR_H */
# ifdef HAVE_SYS_DIR_H
# include <sys/dir.h>
# endif /* HAVE_SYS_DIR_H */
# ifdef HAVE_NDIR_H
# include <ndir.h>
# endif /* HAVE_NDIR_H */
# endif /* HAVE_DIRENT_H */
# define DOT_OR_DOTDOT(Basename) \
(Basename[0] == '.' && (Basename[1] == '\0' \
|| (Basename[1] == '.' && Basename[2] == '\0')))
static void
create_300_file_dir (const char *dir)
{
int i;
if (mkdir (dir, 0700))
abort ();
if (chdir (dir))
abort ();
for (i = 0; i < 300; i++)
{
char file_name[4];
FILE *out;
sprintf (file_name, "%03d", i);
out = fopen (file_name, "w");
if (!out)
abort ();
if (fclose (out) == EOF)
abort ();
}
if (chdir (".."))
abort ();
}
static void
remove_dir (const char *dir)
{
DIR *dirp;
if (chdir (dir))
abort ();
dirp = opendir (".");
if (dirp == NULL)
abort ();
while (1)
{
struct dirent *dp = readdir (dirp);
if (dp == NULL)
break;
if (DOT_OR_DOTDOT (dp->d_name))
continue;
if (unlink (dp->d_name))
abort ();
}
closedir (dirp);
if (chdir (".."))
abort ();
if (rmdir (dir))
exit (1);
}
int
main ()
{
const char *dir = "conf-dir";
create_300_file_dir (dir);
remove_dir (dir);
exit (0);
}],
jm_cv_func_working_readdir=yes,
jm_cv_func_working_readdir=no,
jm_cv_func_working_readdir=no)])
if test $jm_cv_func_working_readdir = yes; then
AC_DEFINE_UNQUOTED(HAVE_WORKING_READDIR, 1,
[Define if readdir is found to work properly in some unusual cases. ])
fi
])