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#include "util/exception.hh"
#include "util/mmap.hh"
#include "util/scoped.hh"
#include <iostream>
#include <assert.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <unistd.h>
namespace util {
scoped_mmap::~scoped_mmap() {
if (data_ != (void*)-1) {
// Thanks Denis Filimonov for pointing on NFS likes msync first.
if (msync(data_, size_, MS_SYNC) || munmap(data_, size_)) {
std::cerr << "msync or mmap failed for " << size_ << " bytes." << std::endl;
abort();
}
}
}
void scoped_memory::reset(void *data, std::size_t size, Alloc source) {
switch(source_) {
case MMAP_ALLOCATED:
scoped_mmap(data_, size_);
break;
case ARRAY_ALLOCATED:
delete [] reinterpret_cast<char*>(data_);
break;
case MALLOC_ALLOCATED:
free(data_);
break;
case NONE_ALLOCATED:
break;
}
data_ = data;
size_ = size;
source_ = source;
}
void scoped_memory::call_realloc(std::size_t size) {
assert(source_ == MALLOC_ALLOCATED || source_ == NONE_ALLOCATED);
void *new_data = realloc(data_, size);
if (!new_data) {
reset();
} else {
reset(new_data, size, MALLOC_ALLOCATED);
}
}
void *MapOrThrow(std::size_t size, bool for_write, int flags, bool prefault, int fd, off_t offset) {
#ifdef MAP_POPULATE // Linux specific
if (prefault) {
flags |= MAP_POPULATE;
}
#endif
int protect = for_write ? (PROT_READ | PROT_WRITE) : PROT_READ;
void *ret = mmap(NULL, size, protect, flags, fd, offset);
if (ret == MAP_FAILED) {
UTIL_THROW(ErrnoException, "mmap failed for size " << size << " at offset " << offset);
}
return ret;
}
namespace {
void ReadAll(int fd, void *to_void, std::size_t amount) {
uint8_t *to = static_cast<uint8_t*>(to_void);
while (amount) {
ssize_t ret = read(fd, to, amount);
if (ret == -1) UTIL_THROW(ErrnoException, "Reading " << amount << " from fd " << fd << " failed.");
if (ret == 0) UTIL_THROW(Exception, "Hit EOF in fd " << fd << " but there should be " << amount << " more bytes to read.");
amount -= ret;
to += ret;
}
}
} // namespace
const int kFileFlags =
#ifdef MAP_FILE
MAP_FILE | MAP_SHARED
#else
MAP_SHARED
#endif
;
void MapRead(LoadMethod method, int fd, off_t offset, std::size_t size, scoped_memory &out) {
switch (method) {
case LAZY:
out.reset(MapOrThrow(size, false, kFileFlags, false, fd, offset), size, scoped_memory::MMAP_ALLOCATED);
break;
case POPULATE_OR_LAZY:
#ifdef MAP_POPULATE
case POPULATE_OR_READ:
#endif
out.reset(MapOrThrow(size, false, kFileFlags, true, fd, offset), size, scoped_memory::MMAP_ALLOCATED);
break;
#ifndef MAP_POPULATE
case POPULATE_OR_READ:
#endif
case READ:
out.reset(malloc(size), size, scoped_memory::MALLOC_ALLOCATED);
if (!out.get()) UTIL_THROW(util::ErrnoException, "Allocating " << size << " bytes with malloc");
if (-1 == lseek(fd, offset, SEEK_SET)) UTIL_THROW(ErrnoException, "lseek to " << offset << " in fd " << fd << " failed.");
ReadAll(fd, out.get(), size);
break;
}
}
void *MapAnonymous(std::size_t size) {
return MapOrThrow(size, true,
#ifdef MAP_ANONYMOUS
MAP_ANONYMOUS // Linux
#else
MAP_ANON // BSD
#endif
| MAP_PRIVATE, false, -1, 0);
}
void *MapZeroedWrite(const char *name, std::size_t size, scoped_fd &file) {
file.reset(open(name, O_CREAT | O_RDWR | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH));
if (-1 == file.get())
UTIL_THROW(ErrnoException, "Failed to open " << name << " for writing");
if (-1 == ftruncate(file.get(), size))
UTIL_THROW(ErrnoException, "ftruncate on " << name << " to " << size << " failed");
try {
return MapOrThrow(size, true, kFileFlags, false, file.get(), 0);
} catch (ErrnoException &e) {
e << " in file " << name;
throw;
}
}
} // namespace util
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