113 lines
4.5 KiB
C++
113 lines
4.5 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#undef _FORTIFY_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#include <sys/resource.h>
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#include <sys/types.h>
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#include <sys/uio.h>
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#include <sys/vfs.h>
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#include <unistd.h>
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#if __LP64__
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#error This code is only needed on 32-bit systems!
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#endif
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// System calls we need.
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extern "C" int __fcntl64(int, int, void*);
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extern "C" int __llseek(int, unsigned long, unsigned long, off64_t*, int);
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extern "C" int __preadv64(int, const struct iovec*, int, long, long);
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extern "C" int __pwritev64(int, const struct iovec*, int, long, long);
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// For fcntl we use the fcntl64 system call to signal that we're using struct flock64.
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int fcntl(int fd, int cmd, ...) {
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va_list ap;
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va_start(ap, cmd);
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void* arg = va_arg(ap, void*);
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va_end(ap);
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return __fcntl64(fd, cmd, arg);
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}
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// For lseek64 we need to use the llseek system call which splits the off64_t in two and
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// returns the off64_t result via a pointer because 32-bit kernels can't return 64-bit results.
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off64_t lseek64(int fd, off64_t off, int whence) {
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off64_t result;
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unsigned long off_hi = static_cast<unsigned long>(off >> 32);
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unsigned long off_lo = static_cast<unsigned long>(off);
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if (__llseek(fd, off_hi, off_lo, &result, whence) < 0) {
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return -1;
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}
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return result;
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}
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// There is no pread for 32-bit off_t, so we need to widen and call pread64.
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ssize_t pread(int fd, void* buf, size_t byte_count, off_t offset) {
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return pread64(fd, buf, byte_count, static_cast<off64_t>(offset));
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}
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// There is no pwrite for 32-bit off_t, so we need to widen and call pwrite64.
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ssize_t pwrite(int fd, const void* buf, size_t byte_count, off_t offset) {
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return pwrite64(fd, buf, byte_count, static_cast<off64_t>(offset));
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}
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// On LP32, there is no off_t preadv/pwritev, and even the 64-bit preadv/pwritev
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// don't use off64_t (see SYSCALLS.TXT for more). Here, this means that we need
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// to implement all four functions because the two system calls don't match any
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// of the userspace functions. Unlike llseek, the pair is split lo-hi, not hi-lo.
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ssize_t preadv(int fd, const struct iovec* ios, int count, off_t offset) {
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return __preadv64(fd, ios, count, offset, 0);
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}
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ssize_t preadv64(int fd, const struct iovec* ios, int count, off64_t offset) {
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return __preadv64(fd, ios, count, offset, offset >> 32);
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}
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ssize_t pwritev(int fd, const struct iovec* ios, int count, off_t offset) {
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return __pwritev64(fd, ios, count, offset, 0);
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}
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ssize_t pwritev64(int fd, const struct iovec* ios, int count, off64_t offset) {
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return __pwritev64(fd, ios, count, offset, offset >> 32);
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}
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// There is no fallocate for 32-bit off_t, so we need to widen and call fallocate64.
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int fallocate(int fd, int mode, off_t offset, off_t length) {
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return fallocate64(fd, mode, static_cast<off64_t>(offset), static_cast<off64_t>(length));
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}
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// There is no getrlimit64 system call, so we need to use prlimit64.
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int getrlimit64(int resource, rlimit64* limits64) {
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return prlimit64(0, resource, NULL, limits64);
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}
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// There is no setrlimit64 system call, so we need to use prlimit64.
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int setrlimit64(int resource, const rlimit64* limits64) {
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return prlimit64(0, resource, limits64, NULL);
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}
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