libc: Split FORTIFY into its own headers
This patch cleans up our standard headers by moving most of the FORTIFY
cruft out in to its own sandbox. In order to include the *_chk and
*_real declarations, you can either enable FORTIFY, or `#define
__BIONIC_DECLARE_FORTIFY_HELPERS`.
Both sys/select.h and strings.h are explicitly ignored by this patch.
Both of these files have very small __BIONIC_FORTIFY blocks, and don't
define any actual FORTIFY'ed functions (just macros, and 3 *_chk
functions).
This patch also makes the versioner ignore the FORTIFY implementation
headers, since we're guaranteed to pick the FORTIFY'ed headers up when
looking at the regular headers. (...Not to mention that making the
FORTIFY'ed headers freestanding would be annoying to do and maintain for
~no benefit).
We bake the knowledge of where FORTIFY headers live directly into the
versioner. We could go with a more general approach (e.g. adding an -X
IGNORED_FILE flag that tells the versioner to ignore
$HEADER_PATH/$IGNORED_FILE), but we'd then have to repeat that for every
test, every manual invocation of the versioner, etc. for no benefit
that's obvious to me.
Bug: 12231437
Test: m checkbuild on bullhead internal master + CtsBionicTestCases. no
new errors.
Change-Id: Iffc0cc609009b33d989cdaddde0a809282131a5b
diff --git a/libc/include/bits/fortify/stdlib.h b/libc/include/bits/fortify/stdlib.h
new file mode 100644
index 0000000..bda1d45
--- /dev/null
+++ b/libc/include/bits/fortify/stdlib.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _STDLIB_H
+#error "Never include this file directly; instead, include <stdlib.h>"
+#endif
+
+#if defined(__BIONIC_FORTIFY)
+#define __realpath_buf_too_small_str \
+ "realpath output parameter must be NULL or a >= PATH_MAX bytes buffer"
+
+/* PATH_MAX is unavailable without polluting the namespace, but it's always 4096 on Linux */
+#define __PATH_MAX 4096
+
+#if defined(__clang__)
+
+__BIONIC_ERROR_FUNCTION_VISIBILITY
+char* realpath(const char* path, char* resolved) __overloadable
+ __enable_if(__bos(resolved) != __BIONIC_FORTIFY_UNKNOWN_SIZE &&
+ __bos(resolved) < __PATH_MAX, __realpath_buf_too_small_str)
+ __errorattr(__realpath_buf_too_small_str);
+
+/* No need for a FORTIFY version; the only things we can catch are at
+ * compile-time.
+ */
+
+#else /* defined(__clang__) */
+
+char* __realpath_real(const char*, char*) __RENAME(realpath);
+__errordecl(__realpath_size_error, __realpath_buf_too_small_str);
+
+__BIONIC_FORTIFY_INLINE
+char* realpath(const char* path, char* resolved) {
+ size_t bos = __bos(resolved);
+
+ if (bos != __BIONIC_FORTIFY_UNKNOWN_SIZE && bos < __PATH_MAX) {
+ __realpath_size_error();
+ }
+
+ return __realpath_real(path, resolved);
+}
+
+#endif /* defined(__clang__) */
+
+#undef __PATH_MAX
+#undef __realpath_buf_too_small_str
+#endif /* defined(__BIONIC_FORTIFY) */