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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <errno.h>
#include <algorithm>
#include <cstdint>
#include "android-base/logging.h"
#include "wifilogd/local_utils.h"
#include "wifilogd/os.h"
namespace android {
namespace wifilogd {
using local_utils::GetMaxVal;
namespace {
constexpr auto kMaxNanoSeconds = 1000 * 1000 * 1000 - 1;
}
Os::Os() : raw_os_(new RawOs()) {}
Os::Os(std::unique_ptr<RawOs> raw_os) : raw_os_(std::move(raw_os)) {}
Os::~Os() {}
Os::Timestamp Os::GetTimestamp(clockid_t clock_id) const {
struct timespec now_timespec;
int failed = raw_os_->ClockGettime(clock_id, &now_timespec);
if (failed) {
LOG(FATAL) << "Unexpected error: " << std::strerror(errno);
}
CHECK(now_timespec.tv_nsec <= kMaxNanoSeconds);
Timestamp now_timestamp;
now_timestamp.secs = SAFELY_CLAMP(
now_timespec.tv_sec, uint32_t, 0,
// The upper-bound comes from the source-type on 32-bit platforms,
// and the dest-type on 64-bit platforms. Using min(), we can figure out
// which type to use for the upper bound, without resorting to macros.
std::min(static_cast<uintmax_t>(GetMaxVal(now_timestamp.secs)),
static_cast<uintmax_t>(GetMaxVal(now_timespec.tv_sec))));
now_timestamp.nsecs =
SAFELY_CLAMP(now_timespec.tv_nsec, uint32_t, 0, kMaxNanoSeconds);
return now_timestamp;
}
std::tuple<size_t, Os::Errno> Os::Write(int fd, const void* buf,
size_t buflen) {
// write() takes a size_t, but returns an ssize_t. That means that the
// largest successful write that write() can report is the maximal ssize_t.
// Passing a larger |buflen| risks mistakenly reporting a truncated write.
CHECK(buflen <= GetMaxVal<ssize_t>());
const ssize_t res = raw_os_->Write(fd, buf, buflen);
if (res < 0) {
return {0, errno};
}
CHECK(res <=
SAFELY_CLAMP(buflen, ssize_t, 0,
GetMaxVal<ssize_t>())); // Abort on buffer overflow.
// Note that |res| may be less than buflen. However, a) a short write is
// not an error, and b) |errno| may be stale, as |errno| is only guaranteed to
// be set if an error occurred. Hence, we return Errno of 0 unconditionally.
// See http://yarchive.net/comp/linux/write_error_return.html
return {res, 0};
}
} // namespace wifilogd
} // namespace android
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