Clean up the 32-bit kernel support, fix LP64 fcntl declaration.
In practice, thanks to all the registers the stubs don't actually change,
but it's confusing to have an incorrect declaration.
I suspect that fcntl remains broken for aarch64; it happens to work for
x86_64 because the first vararg argument gets placed in the right register
anyway, but I have no reason to believe that's true for aarch64.
This patch adds a unit test, though, so we'll be able to tell when we get
as far as running the unit tests.
Change-Id: I58dd0054fe99d7d51d04c22781d8965dff1afbf3
diff --git a/libc/bionic/legacy_32_bit_support.cpp b/libc/bionic/legacy_32_bit_support.cpp
new file mode 100644
index 0000000..884dd8b
--- /dev/null
+++ b/libc/bionic/legacy_32_bit_support.cpp
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+
+#include <errno.h>
+#include <stdarg.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
+#include <sys/vfs.h>
+#include <unistd.h>
+#include <unistd.h>
+
+#if __LP64__
+#error This code is only needed on 32-bit systems!
+#endif
+
+// System calls we need.
+extern "C" int __fcntl64(int, int, void*);
+extern "C" int __fstatfs64(int, size_t, struct statfs*);
+extern "C" int __llseek(int, unsigned long, unsigned long, off64_t*, int);
+extern "C" int __statfs64(const char*, size_t, struct statfs*);
+
+// For fcntl we use the fcntl64 system call to signal that we're using struct flock64.
+int fcntl(int fd, int cmd, ...) {
+ va_list ap;
+
+ va_start(ap, cmd);
+ void* arg = va_arg(ap, void*);
+ va_end(ap);
+
+ return __fcntl64(fd, cmd, arg);
+}
+
+// For fstatfs we need to add the extra argument giving the kernel the size of the buffer.
+int fstatfs(int fd, struct statfs* stat) {
+ return __fstatfs64(fd, sizeof(*stat), stat);
+}
+
+// For statfs we need to add the extra argument giving the kernel the size of the buffer.
+int statfs(const char* path, struct statfs* stat) {
+ return __statfs64(path, sizeof(*stat), stat);
+}
+
+// For lseek64 we need to use the llseek system call which splits the off64_t in two and
+// returns the off64_t result via a pointer because 32-bit kernels can't return 64-bit results.
+off64_t lseek64(int fd, off64_t off, int whence) {
+ off64_t result;
+ unsigned long off_hi = static_cast<unsigned long>(off >> 32);
+ unsigned long off_lo = static_cast<unsigned long>(off);
+ if (__llseek(fd, off_hi, off_lo, &result, whence) < 0) {
+ return -1;
+ }
+ return result;
+}
+
+// There is no pread for 32-bit off_t, so we need to widen and call pread64.
+ssize_t pread(int fd, void* buf, size_t byte_count, off_t offset) {
+ return pread64(fd, buf, byte_count, static_cast<off64_t>(offset));
+}
+
+// There is no pwrite for 32-bit off_t, so we need to widen and call pwrite64.
+ssize_t pwrite(int fd, const void* buf, size_t byte_count, off_t offset) {
+ return pwrite64(fd, buf, byte_count, static_cast<off64_t>(offset));
+}