blob: 21174bc9a4c9fb0e8d482e38bb6f7f423bc6b97c [file] [log] [blame]
// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/lib/files/file.h"
#include <assert.h>
#include <fcntl.h>
#include <limits.h>
#include <sys/stat.h>
#include <unistd.h>
#define FILE_CREATE_MODE 0666
#define BINARY_MODE 0
#include <fbl/unique_fd.h>
#include "src/lib/files/eintr_wrapper.h"
#include "src/lib/files/file_descriptor.h"
#include "src/lib/files/scoped_temp_dir.h"
namespace files {
namespace {
template <typename T>
bool ReadFileDescriptor(int fd, T* result) {
assert(result);
result->clear();
struct stat s;
if (int res = fstat(fd, &s); res < 0) {
return false;
}
// Some (many?) file implementations on Fuchsia do not report their size.
//
// See e.g. https://fxbug.dev/42070489.
const size_t size = s.st_size;
if (size != 0) {
result->resize(size);
}
for (size_t offset = 0;;) {
size_t count = [&]() {
if (size != 0) {
return size - offset;
}
constexpr size_t kBufferSize = 1 << 16;
result->resize(offset + kBufferSize);
return kBufferSize;
}();
ssize_t bytes_read = HANDLE_EINTR(read(fd, &result->data()[offset], count));
if (bytes_read < 0) {
result->clear();
return false;
}
if (bytes_read == 0) {
result->resize(offset);
return true;
}
offset += bytes_read;
}
}
} // namespace
bool WriteFile(const std::string& path, std::string_view data) {
return WriteFile(path, data.data(), data.size());
}
bool WriteFile(const std::string& path, const char* data, ssize_t size) {
return WriteFileAt(AT_FDCWD, path, data, size);
}
bool WriteFileAt(int dirfd, const std::string& path, const char* data, ssize_t size) {
fbl::unique_fd fd(
HANDLE_EINTR(openat(dirfd, path.c_str(), O_CREAT | O_TRUNC | O_WRONLY, FILE_CREATE_MODE)));
if (!fd.is_valid())
return false;
return fxl::WriteFileDescriptor(fd.get(), data, size);
}
bool WriteFileInTwoPhases(const std::string& path, std::string_view data,
const std::string& temp_root) {
ScopedTempDir temp_dir(temp_root);
std::string temp_file_path;
if (!temp_dir.NewTempFile(&temp_file_path)) {
return false;
}
if (!WriteFile(temp_file_path, data.data(), data.size())) {
return false;
}
if (rename(temp_file_path.c_str(), path.c_str()) != 0) {
return false;
}
return true;
}
bool ReadFileToString(const std::string& path, std::string* result) {
return ReadFileToStringAt(AT_FDCWD, path, result);
}
bool ReadFileDescriptorToString(int fd, std::string* result) {
return ReadFileDescriptor(fd, result);
}
bool ReadFileToStringAt(int dirfd, const std::string& path, std::string* result) {
fbl::unique_fd fd(openat(dirfd, path.c_str(), O_RDONLY));
return ReadFileDescriptor(fd.get(), result);
}
bool ReadFileToVector(const std::string& path, std::vector<uint8_t>* result) {
fbl::unique_fd fd(open(path.c_str(), O_RDONLY | BINARY_MODE));
return ReadFileDescriptor(fd.get(), result);
}
bool ReadFileDescriptorToVector(int fd, std::vector<uint8_t>* result) {
return ReadFileDescriptor(fd, result);
}
bool ReadFileToVectorAt(int dirfd, const std::string& path, std::vector<uint8_t>* result) {
fbl::unique_fd fd(openat(dirfd, path.c_str(), O_RDONLY));
return ReadFileDescriptor(fd.get(), result);
}
bool IsFile(const std::string& path) { return IsFileAt(AT_FDCWD, path); }
bool IsFileAt(int dirfd, const std::string& path) {
struct stat stat_buffer;
if (fstatat(dirfd, path.c_str(), &stat_buffer, /* flags = */ 0) != 0)
return false;
return S_ISREG(stat_buffer.st_mode);
}
bool GetFileSize(const std::string& path, uint64_t* size) {
return GetFileSizeAt(AT_FDCWD, path, size);
}
bool GetFileSizeAt(int dirfd, const std::string& path, uint64_t* size) {
struct stat stat_buffer;
if (fstatat(dirfd, path.c_str(), &stat_buffer, /* flags = */ 0) != 0)
return false;
*size = stat_buffer.st_size;
return true;
}
} // namespace files