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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <sys/mman.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "mozilla/Assertions.h"
#include "mozilla/Sprintf.h"
#include "PlatformMacros.h"
#include "AutoObjectMapper.h"
// A helper function for creating failure error messages in
// AutoObjectMapper*::Map.
static void failedToMessage(void (*aLog)(const char*), const char* aHowFailed,
std::string aFileName) {
char buf[300];
SprintfLiteral(buf, "AutoObjectMapper::Map: Failed to %s \'%s\'", aHowFailed,
aFileName.c_str());
buf[sizeof(buf) - 1] = 0;
aLog(buf);
}
AutoObjectMapperPOSIX::AutoObjectMapperPOSIX(void (*aLog)(const char*))
: mImage(nullptr), mSize(0), mLog(aLog), mIsMapped(false) {}
AutoObjectMapperPOSIX::~AutoObjectMapperPOSIX() {
if (!mIsMapped) {
// There's nothing to do.
MOZ_ASSERT(!mImage);
MOZ_ASSERT(mSize == 0);
return;
}
MOZ_ASSERT(mSize > 0);
// The following assertion doesn't necessarily have to be true,
// but we assume (reasonably enough) that no mmap facility would
// be crazy enough to map anything at page zero.
MOZ_ASSERT(mImage);
munmap(mImage, mSize);
}
bool AutoObjectMapperPOSIX::Map(/*OUT*/ void** start, /*OUT*/ size_t* length,
std::string fileName) {
MOZ_ASSERT(!mIsMapped);
int fd = open(fileName.c_str(), O_RDONLY);
if (fd == -1) {
failedToMessage(mLog, "open", fileName);
return false;
}
struct stat st;
int err = fstat(fd, &st);
size_t sz = (err == 0) ? st.st_size : 0;
if (err != 0 || sz == 0) {
failedToMessage(mLog, "fstat", fileName);
close(fd);
return false;
}
void* image = mmap(nullptr, sz, PROT_READ, MAP_SHARED, fd, 0);
if (image == MAP_FAILED) {
failedToMessage(mLog, "mmap", fileName);
close(fd);
return false;
}
close(fd);
mIsMapped = true;
mImage = *start = image;
mSize = *length = sz;
return true;
}
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