diff --git a/elf/chroot_canon.c b/elf/chroot_canon.c index 5db13c22bd..34869f1c05 100644 --- a/elf/chroot_canon.c +++ b/elf/chroot_canon.c @@ -23,8 +23,7 @@ #include #include #include - -#include +#include #include #ifndef PATH_MAX @@ -126,7 +125,7 @@ chroot_canon (const char *chroot, const char *name) char *buf = alloca (PATH_MAX); size_t len; - if (++num_links > __eloop_threshold ()) + if (++num_links > MIN_ELOOP_THRESHOLD) { __set_errno (ELOOP); goto error; diff --git a/hurd/lookup-retry.c b/hurd/lookup-retry.c index 6b94a10eae..ac8925ec1b 100644 --- a/hurd/lookup-retry.c +++ b/hurd/lookup-retry.c @@ -24,7 +24,7 @@ #include #include #include <_itoa.h> -#include +#include #include /* Translate the error from dir_lookup into the error the user sees. */ @@ -113,7 +113,7 @@ __hurd_file_name_lookup_retry (error_t (*use_init_port) /* Fall through. */ case FS_RETRY_NORMAL: - if (nloops++ >= __eloop_threshold ()) + if (nloops++ >= MIN_ELOOP_THRESHOLD) { __mach_port_deallocate (__mach_task_self (), *result); err = ELOOP; @@ -207,7 +207,7 @@ __hurd_file_name_lookup_retry (error_t (*use_init_port) dirport = INIT_PORT_CRDIR; if (*result != MACH_PORT_NULL) __mach_port_deallocate (__mach_task_self (), *result); - if (nloops++ >= __eloop_threshold ()) + if (nloops++ >= MIN_ELOOP_THRESHOLD) { err = ELOOP; goto out; diff --git a/stdlib/canonicalize.c b/stdlib/canonicalize.c index 528bf49acf..dca6fca5fb 100644 --- a/stdlib/canonicalize.c +++ b/stdlib/canonicalize.c @@ -36,17 +36,19 @@ #include #include -#include #include #include #include #include #ifdef _LIBC +# include # include # define GCC_LINT 1 # define _GL_ATTRIBUTE_PURE __attribute__ ((__pure__)) #else +# include +# define MIN_ELOOP_THRESHOLD __eloop_threshold () # define __canonicalize_file_name canonicalize_file_name # define __realpath realpath # define __strdup strdup @@ -310,7 +312,7 @@ realpath_stk (const char *name, char *resolved, struct realpath_bufs *bufs) } if (0 <= n) { - if (++num_links > __eloop_threshold ()) + if (++num_links > MIN_ELOOP_THRESHOLD) { __set_errno (ELOOP); goto error; diff --git a/stdlib/tst-canon-bz26341.c b/stdlib/tst-canon-bz26341.c index a9b823b21e..b62b2cae44 100644 --- a/stdlib/tst-canon-bz26341.c +++ b/stdlib/tst-canon-bz26341.c @@ -23,7 +23,7 @@ #include #define __sysconf sysconf -#include +#include #include #include #include @@ -54,7 +54,7 @@ create_link (void) /* Create MAXLINKS symbolic links to the temporary filename. On exit, linkname has the last link created. */ char *prevlink = filename; - int maxlinks = __eloop_threshold (); + int maxlinks = MIN_ELOOP_THRESHOLD; for (int i = 0; i < maxlinks; i++) { linkname = xasprintf ("%s%d", filename, i); diff --git a/sysdeps/generic/eloop-threshold.h b/sysdeps/generic/eloop-threshold.h deleted file mode 100644 index 02363689b0..0000000000 --- a/sysdeps/generic/eloop-threshold.h +++ /dev/null @@ -1,72 +0,0 @@ -/* Threshold at which to diagnose ELOOP. Generic version. - Copyright (C) 2012-2025 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 - . */ - -#ifndef _ELOOP_THRESHOLD_H -#define _ELOOP_THRESHOLD_H 1 - -#include -#include - -/* 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/generic/min-eloop-threshold.h b/sysdeps/generic/min-eloop-threshold.h new file mode 100644 index 0000000000..2ac12edeef --- /dev/null +++ b/sysdeps/generic/min-eloop-threshold.h @@ -0,0 +1,42 @@ +/* Minimum threshold at which to diagnose ELOOP. Generic version. + Copyright (C) 2012-2025 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 + . */ + +#ifndef _MIN_ELOOP_THRESHOLD_H +#define _MIN_ELOOP_THRESHOLD_H 1 + +/* 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. + + 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. */ + +#define MIN_ELOOP_THRESHOLD 40 + +#endif diff --git a/sysdeps/mach/hurd/eloop-threshold.h b/sysdeps/mach/hurd/min-eloop-threshold.h similarity index 83% rename from sysdeps/mach/hurd/eloop-threshold.h rename to sysdeps/mach/hurd/min-eloop-threshold.h index 13842b489d..98ecf49d00 100644 --- a/sysdeps/mach/hurd/eloop-threshold.h +++ b/sysdeps/mach/hurd/min-eloop-threshold.h @@ -1,4 +1,4 @@ -/* Threshold at which to diagnose ELOOP. Hurd version. +/* Minimum threshold at which to diagnose ELOOP. Hurd version. Copyright (C) 2012-2025 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -16,8 +16,8 @@ License along with the GNU C Library; if not, see . */ -#ifndef _ELOOP_THRESHOLD_H -#define _ELOOP_THRESHOLD_H 1 +#ifndef _MIN_ELOOP_THRESHOLD_H +#define _MIN_ELOOP_THRESHOLD_H 1 /* Return the maximum number of symlink traversals to permit before diagnosing ELOOP. @@ -28,10 +28,6 @@ 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; -} +#define MIN_ELOOP_THRESHOLD 32 -#endif /* eloop-threshold.h */ +#endif diff --git a/sysdeps/mach/hurd/sysconf.c b/sysdeps/mach/hurd/sysconf.c index cb4899a67b..bf610901f4 100644 --- a/sysdeps/mach/hurd/sysconf.c +++ b/sysdeps/mach/hurd/sysconf.c @@ -19,8 +19,8 @@ #include #include -#include +#include -#define SYMLOOP_MAX (__eloop_threshold ()) +#define SYMLOOP_MAX MIN_ELOOP_THRESHOLD #include