diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/generic/eloop-threshold.h | 72 | ||||
| -rw-r--r-- | sysdeps/mach/hurd/bits/local_lim.h | 13 | ||||
| -rw-r--r-- | sysdeps/mach/hurd/eloop-threshold.h | 37 | ||||
| -rw-r--r-- | sysdeps/mach/hurd/sys/param.h | 3 | ||||
| -rw-r--r-- | sysdeps/mach/hurd/sysconf.c | 26 |
5 files changed, 137 insertions, 14 deletions
diff --git a/sysdeps/generic/eloop-threshold.h b/sysdeps/generic/eloop-threshold.h new file mode 100644 index 0000000000..2342d29a23 --- /dev/null +++ b/sysdeps/generic/eloop-threshold.h @@ -0,0 +1,72 @@ +/* Threshold at which to diagnose ELOOP. Generic version. + Copyright (C) 2012 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 + <http://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 */ diff --git a/sysdeps/mach/hurd/bits/local_lim.h b/sysdeps/mach/hurd/bits/local_lim.h index 48411d071c..c957dad767 100644 --- a/sysdeps/mach/hurd/bits/local_lim.h +++ b/sysdeps/mach/hurd/bits/local_lim.h @@ -1,5 +1,5 @@ /* Minimum guaranteed maximum values for system limits. Hurd version. - Copyright (C) 1993,94,96,98,2002 Free Software Foundation, Inc. + Copyright (C) 1993-2012 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 @@ -32,14 +32,3 @@ suitable, and `sysconf' will return a number at least as large. */ #define NGROUPS_MAX 256 - -/* The maximum number of symbolic links that are allowed in a single file - name resolution. When a further link is encountered, the call returns - ELOOP. This name is a GNU extension; POSIX.1 has no such limit, and BSD - calls it MAXSYMLINKS in <sys/param.h>. (We define the name under - _BSD_SOURCE even without _GNU_SOURCE because our <sys/param.h> uses it - to define MAXSYMLINKS.) */ - -#if defined __USE_GNU || defined __USE_BSD /* 1003.1a defines this */ -#define SYMLOOP_MAX 8 -#endif diff --git a/sysdeps/mach/hurd/eloop-threshold.h b/sysdeps/mach/hurd/eloop-threshold.h new file mode 100644 index 0000000000..b8fae16449 --- /dev/null +++ b/sysdeps/mach/hurd/eloop-threshold.h @@ -0,0 +1,37 @@ +/* Threshold at which to diagnose ELOOP. Hurd version. + Copyright (C) 2012 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 + <http://www.gnu.org/licenses/>. */ + +#ifndef _ELOOP_THRESHOLD_H +#define _ELOOP_THRESHOLD_H 1 + +/* Return the maximum number of symlink traversals to permit + before diagnosing ELOOP. + + In the Hurd version, here we are actually setting the only policy + there is on the system. We use a literal number here rather than + defining SYMLOOP_MAX so that programs don't compile in a number + but instead use sysconf and the number can be changed here to + affect sysconf's result. */ + +static inline unsigned int __attribute__ ((const)) +__eloop_threshold (void) +{ + return 32; +} + +#endif /* eloop-threshold.h */ diff --git a/sysdeps/mach/hurd/sys/param.h b/sysdeps/mach/hurd/sys/param.h index 42f4f46e7d..e58d5175bd 100644 --- a/sysdeps/mach/hurd/sys/param.h +++ b/sysdeps/mach/hurd/sys/param.h @@ -1,4 +1,4 @@ -/* Copyright (C) 1993,1994,1995,1997,1999,2011 Free Software Foundation, Inc. +/* Copyright (C) 1993-2012 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 @@ -83,7 +83,6 @@ #define NBBY CHAR_BIT #define NGROUPS NGROUPS_MAX -#define MAXSYMLINKS SYMLOOP_MAX #define CANBSIZ MAX_CANON /* XXX ? */ /* ARG_MAX is unlimited, but we define NCARGS for BSD programs that want to diff --git a/sysdeps/mach/hurd/sysconf.c b/sysdeps/mach/hurd/sysconf.c new file mode 100644 index 0000000000..6d1666d93c --- /dev/null +++ b/sysdeps/mach/hurd/sysconf.c @@ -0,0 +1,26 @@ +/* Return values of system parameters. Hurd version. + Copyright (C) 2012 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 + <http://www.gnu.org/licenses/>. */ + +#include <limits.h> +#include <unistd.h> + +#include <eloop-threshold.h> + +#define SYMLOOP_MAX (__eloop_threshold ()) + +#include <sysdeps/posix/sysconf.c> |