glibc/sysdeps/generic/eloop-threshold.h
Paul Eggert 5a82c74822 Prefer https to http for gnu.org and fsf.org URLs
Also, change sources.redhat.com to sourceware.org.
This patch was automatically generated by running the following shell
script, which uses GNU sed, and which avoids modifying files imported
from upstream:

sed -ri '
  s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g
  s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g
' \
  $(find $(git ls-files) -prune -type f \
      ! -name '*.po' \
      ! -name 'ChangeLog*' \
      ! -path COPYING ! -path COPYING.LIB \
      ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \
      ! -path manual/texinfo.tex ! -path scripts/config.guess \
      ! -path scripts/config.sub ! -path scripts/install-sh \
      ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \
      ! -path INSTALL ! -path  locale/programs/charmap-kw.h \
      ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \
      ! '(' -name configure \
            -execdir test -f configure.ac -o -f configure.in ';' ')' \
      ! '(' -name preconfigure \
            -execdir test -f preconfigure.ac ';' ')' \
      -print)

and then by running 'make dist-prepare' to regenerate files built
from the altered files, and then executing the following to cleanup:

  chmod a+x sysdeps/unix/sysv/linux/riscv/configure
  # Omit irrelevant whitespace and comment-only changes,
  # perhaps from a slightly-different Autoconf version.
  git checkout -f \
    sysdeps/csky/configure \
    sysdeps/hppa/configure \
    sysdeps/riscv/configure \
    sysdeps/unix/sysv/linux/csky/configure
  # Omit changes that caused a pre-commit check to fail like this:
  # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines
  git checkout -f \
    sysdeps/powerpc/powerpc64/ppc-mcount.S \
    sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
  # Omit change that caused a pre-commit check to fail like this:
  # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline
  git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 02:43:31 -07:00

73 lines
2.9 KiB
C

/* Threshold at which to diagnose ELOOP. Generic version.
Copyright (C) 2012-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _ELOOP_THRESHOLD_H
#define _ELOOP_THRESHOLD_H 1
#include <limits.h>
#include <sys/param.h>
/* POSIX specifies SYMLOOP_MAX as the "Maximum number of symbolic
links that can be reliably traversed in the resolution of a
pathname in the absence of a loop." This makes it a minimum that
we should certainly accept. But it leaves open the possibility
that more might sometimes work--just not "reliably".
For example, Linux implements a complex policy whereby there is a
small limit on the number of direct symlink traversals (a symlink
to a symlink to a symlink), but larger limit on the total number of
symlink traversals overall. Hence the SYMLOOP_MAX number should be
the small one, but the limit library functions enforce on users
should be the larger one.
So, we use the larger of the reported SYMLOOP_MAX (if any) and our
own constant MIN_ELOOP_THRESHOLD, below. This constant should be
large enough that it never rules out a file name and directory tree
that the underlying system (i.e. calls to 'open' et al) would
resolve successfully. It should be small enough that actual loops
are detected without a huge number of iterations. */
#ifndef MIN_ELOOP_THRESHOLD
# define MIN_ELOOP_THRESHOLD 40
#endif
/* Return the maximum number of symlink traversals to permit
before diagnosing ELOOP. */
static inline unsigned int __attribute__ ((const))
__eloop_threshold (void)
{
#ifdef SYMLOOP_MAX
const int symloop_max = SYMLOOP_MAX;
#else
/* The function is marked 'const' even though we use memory and
call a function, because sysconf is required to return the
same value in every call and so it must always be safe to
call __eloop_threshold exactly once and reuse the value. */
static long int sysconf_symloop_max;
if (sysconf_symloop_max == 0)
sysconf_symloop_max = __sysconf (_SC_SYMLOOP_MAX);
const unsigned int symloop_max = (sysconf_symloop_max <= 0
? _POSIX_SYMLOOP_MAX
: sysconf_symloop_max);
#endif
return MAX (symloop_max, MIN_ELOOP_THRESHOLD);
}
#endif /* eloop-threshold.h */