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Fix compilation errors with CC="clang -D_FORTIFY_SOURCE=2" on Android
From: |
Bruno Haible |
Subject: |
Fix compilation errors with CC="clang -D_FORTIFY_SOURCE=2" on Android |
Date: |
Mon, 30 Jan 2023 00:06:31 +0100 |
On Android, clang does not define _FORTIFY_SOURCE by default, but the Android
NDK sets CC to something like "clang -D_FORTIFY_SOURCE=2". Then, we see
compilation errors, such as
clang -ferror-limit=0 -D_FORTIFY_SOURCE=2 -DHAVE_CONFIG_H -DEXEEXT=\"\"
-DEXEEXT=\"\" -DNO_XMALLOC -DEXEEXT=\"\" -I. -I../../gllib -I..
-DGNULIB_STRICT_CHECKING=1 -I/data/data/com.termux/files/home/local/include
-Wall -fvisibility=hidden -O2 -c -o strverscmp.o ../../gllib/strverscmp.c
In file included from ../../gllib/strverscmp.c:26:
In file included from ./string.h:41:
In file included from /data/data/com.termux/files/usr/include/string.h:187:
/data/data/com.termux/files/usr/include/bits/fortify/string.h:95:47: error: use
of undeclared identifier '__USE_FORTIFY_LEVEL'
__clang_error_if(__bos_unevaluated_le(__bos(dst),
__builtin_strlen(src)),
^
../../gllib/cdefs.h:144:48: note: expanded from macro '__bos'
#define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
^
In file included from ../../gllib/strverscmp.c:26:
In file included from ./string.h:41:
In file included from /data/data/com.termux/files/usr/include/string.h:187:
/data/data/com.termux/files/usr/include/bits/fortify/string.h:95:47: error: use
of undeclared identifier '__USE_FORTIFY_LEVEL'
../../gllib/cdefs.h:144:48: note: expanded from macro '__bos'
#define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
^
Find the full list of errors from a Gnulib testdir attached.
The cause is that Android has its own framework for defining fortified
variants of the string operations, and like glibc it uses macros named
'__bos' and '__bos0'. But these macros have different definitions in
Android than in glibc. Using the glibc definition on Android leads to
trouble (because it references an undefined variable __USE_FORTIFY_LEVEL).
And undefining these macros after use leads to trouble as well (namely,
link errors for the undefined function '__bos0').
So, gnulib's cdefs.h and libc-config.h needs to avoid fiddling with
the Fortify stuff when used in Gnulib. The Gnulib modules that use
libc-config, namely
canonicalize-lgpl
fnmatch
glibc-internal/dynarray
glibc-internal/scratch_buffer
glob, glob-h
mktime
nstrftime
random, random_r
strverscmp
tempname
are unlikely to ever use this Fortify stuff.
This patch fixes the compilation errors. The use of __GNULIB_CDEFS has a
precedent; I therefore don't expect that it will trigger resistence during
the next merge back into glibc.
2023-01-29 Bruno Haible <bruno@clisp.org>
Fix compilation errors with CC="clang -D_FORTIFY_SOURCE=2" on Android.
Reported by Alexey Rochev <equeim@gmail.com> in
<https://lists.gnu.org/archive/html/bug-gnu-libiconv/2023-01/msg00019.html>.
* lib/cdefs.h (__bos, __bos0, __glibc_objsize0, __glibc_objsize,
__glibc_safe_len_cond, __glibc_unsigned_or_positive,
__glibc_safe_or_unknown_len, __glibc_unsafe_len, __glibc_fortify,
__glibc_fortify_n): Don't define these macros in Gnulib.
* lib/libc-config.h: Don't undefine these macros in Gnulib.
diff --git a/lib/cdefs.h b/lib/cdefs.h
index 09a3d19b23..412f036ce3 100644
--- a/lib/cdefs.h
+++ b/lib/cdefs.h
@@ -140,32 +140,37 @@
#endif
+/* Gnulib avoids these definitions, as they don't work on non-glibc platforms.
+ In particular, __bos and __bos0 are defined differently in the Android libc.
+ */
+#ifndef __GNULIB_CDEFS
+
/* Fortify support. */
-#define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
-#define __bos0(ptr) __builtin_object_size (ptr, 0)
+# define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
+# define __bos0(ptr) __builtin_object_size (ptr, 0)
/* Use __builtin_dynamic_object_size at _FORTIFY_SOURCE=3 when available. */
-#if __USE_FORTIFY_LEVEL == 3 && (__glibc_clang_prereq (9, 0) \
- || __GNUC_PREREQ (12, 0))
-# define __glibc_objsize0(__o) __builtin_dynamic_object_size (__o, 0)
-# define __glibc_objsize(__o) __builtin_dynamic_object_size (__o, 1)
-#else
-# define __glibc_objsize0(__o) __bos0 (__o)
-# define __glibc_objsize(__o) __bos (__o)
-#endif
+# if __USE_FORTIFY_LEVEL == 3 && (__glibc_clang_prereq (9, 0) \
+ || __GNUC_PREREQ (12, 0))
+# define __glibc_objsize0(__o) __builtin_dynamic_object_size (__o, 0)
+# define __glibc_objsize(__o) __builtin_dynamic_object_size (__o, 1)
+# else
+# define __glibc_objsize0(__o) __bos0 (__o)
+# define __glibc_objsize(__o) __bos (__o)
+# endif
/* Compile time conditions to choose between the regular, _chk and _chk_warn
variants. These conditions should get evaluated to constant and optimized
away. */
-#define __glibc_safe_len_cond(__l, __s, __osz) ((__l) <= (__osz) / (__s))
-#define __glibc_unsigned_or_positive(__l) \
+# define __glibc_safe_len_cond(__l, __s, __osz) ((__l) <= (__osz) / (__s))
+# define __glibc_unsigned_or_positive(__l) \
((__typeof (__l)) 0 < (__typeof (__l)) -1 \
|| (__builtin_constant_p (__l) && (__l) > 0))
/* Length is known to be safe at compile time if the __L * __S <= __OBJSZ
condition can be folded to a constant and if it is true, or unknown (-1) */
-#define __glibc_safe_or_unknown_len(__l, __s, __osz) \
+# define __glibc_safe_or_unknown_len(__l, __s, __osz) \
((__osz) == (__SIZE_TYPE__) -1 \
|| (__glibc_unsigned_or_positive (__l) \
&& __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), \
@@ -175,7 +180,7 @@
/* Conversely, we know at compile time that the length is unsafe if the
__L * __S <= __OBJSZ condition can be folded to a constant and if it is
false. */
-#define __glibc_unsafe_len(__l, __s, __osz) \
+# define __glibc_unsafe_len(__l, __s, __osz) \
(__glibc_unsigned_or_positive (__l) \
&& __builtin_constant_p (__glibc_safe_len_cond ((__SIZE_TYPE__) (__l), \
__s, __osz)) \
@@ -184,7 +189,7 @@
/* Fortify function f. __f_alias, __f_chk and __f_chk_warn must be
declared. */
-#define __glibc_fortify(f, __l, __s, __osz, ...) \
+# define __glibc_fortify(f, __l, __s, __osz, ...) \
(__glibc_safe_or_unknown_len (__l, __s, __osz) \
? __ ## f ## _alias (__VA_ARGS__) \
: (__glibc_unsafe_len (__l, __s, __osz) \
@@ -194,13 +199,16 @@
/* Fortify function f, where object size argument passed to f is the number of
elements and not total size. */
-#define __glibc_fortify_n(f, __l, __s, __osz, ...) \
+# define __glibc_fortify_n(f, __l, __s, __osz, ...) \
(__glibc_safe_or_unknown_len (__l, __s, __osz) \
? __ ## f ## _alias (__VA_ARGS__) \
: (__glibc_unsafe_len (__l, __s, __osz) \
? __ ## f ## _chk_warn (__VA_ARGS__, (__osz) / (__s)) \
: __ ## f ## _chk (__VA_ARGS__, (__osz) / (__s)))) \
+#endif
+
+
#if __GNUC_PREREQ (4,3)
# define __warnattr(msg) __attribute__((__warning__ (msg)))
# define __errordecl(name, msg) \
diff --git a/lib/libc-config.h b/lib/libc-config.h
index 1d28e58c97..5f5ad01037 100644
--- a/lib/libc-config.h
+++ b/lib/libc-config.h
@@ -137,8 +137,6 @@
# undef __attribute_returns_twice__
# undef __attribute_used__
# undef __attribute_warn_unused_result__
-# undef __bos
-# undef __bos0
# undef __errordecl
# undef __extension__
# undef __extern_always_inline
@@ -147,21 +145,13 @@
# undef __fortified_attr_access
# undef __fortify_function
# undef __glibc_c99_flexarr_available
-# undef __glibc_fortify
-# undef __glibc_fortify_n
# undef __glibc_has_attribute
# undef __glibc_has_builtin
# undef __glibc_has_extension
# undef __glibc_likely
# undef __glibc_macro_warning
# undef __glibc_macro_warning1
-# undef __glibc_objsize
-# undef __glibc_objsize0
-# undef __glibc_safe_len_cond
-# undef __glibc_safe_or_unknown_len
# undef __glibc_unlikely
-# undef __glibc_unsafe_len
-# undef __glibc_unsigned_or_positive
# undef __inline
# undef __ptr_t
# undef __restrict
@@ -170,6 +160,18 @@
# undef __va_arg_pack_len
# undef __warnattr
# undef __wur
+# ifndef __GNULIB_CDEFS
+# undef __bos
+# undef __bos0
+# undef __glibc_fortify
+# undef __glibc_fortify_n
+# undef __glibc_objsize
+# undef __glibc_objsize0
+# undef __glibc_safe_len_cond
+# undef __glibc_safe_or_unknown_len
+# undef __glibc_unsafe_len
+# undef __glibc_unsigned_or_positive
+# endif
/* Include our copy of glibc <sys/cdefs.h>. */
# include <cdefs.h>
android-errors.log.gz
Description: application/gzip
- Fix compilation errors with CC="clang -D_FORTIFY_SOURCE=2" on Android,
Bruno Haible <=