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//===--- Linux specialization of the File data structure ------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "file.h"
#include "src/__support/CPP/new.h"
#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
#include "src/errno/libc_errno.h" // For error macros
#include <fcntl.h> // For mode_t and other flags to the open syscall
#include <stdio.h>
#include <sys/syscall.h> // For syscall numbers
namespace __llvm_libc {
namespace {
FileIOResult write_func(File *, const void *, size_t);
FileIOResult read_func(File *, void *, size_t);
ErrorOr<long> seek_func(File *, long, int);
int close_func(File *);
int flush_func(File *);
} // anonymous namespace
class LinuxFile : public File {
int fd;
public:
constexpr LinuxFile(int file_descriptor, uint8_t *buffer, size_t buffer_size,
int buffer_mode, bool owned, File::ModeFlags modeflags)
: File(&write_func, &read_func, &seek_func, &close_func, flush_func,
&cleanup_file<LinuxFile>, buffer, buffer_size, buffer_mode, owned,
modeflags),
fd(file_descriptor) {}
int get_fd() const { return fd; }
};
namespace {
FileIOResult write_func(File *f, const void *data, size_t size) {
auto *lf = reinterpret_cast<LinuxFile *>(f);
int ret = __llvm_libc::syscall_impl(SYS_write, lf->get_fd(), data, size);
if (ret < 0) {
return {0, -ret};
}
return ret;
}
FileIOResult read_func(File *f, void *buf, size_t size) {
auto *lf = reinterpret_cast<LinuxFile *>(f);
int ret = __llvm_libc::syscall_impl(SYS_read, lf->get_fd(), buf, size);
if (ret < 0) {
return {0, -ret};
}
return ret;
}
ErrorOr<long> seek_func(File *f, long offset, int whence) {
auto *lf = reinterpret_cast<LinuxFile *>(f);
long result;
#ifdef SYS_lseek
int ret = __llvm_libc::syscall_impl(SYS_lseek, lf->get_fd(), offset, whence);
result = ret;
#elif defined(SYS__llseek)
long result;
int ret = __llvm_libc::syscall_impl(SYS__llseek, lf->get_fd(), offset >> 32,
offset, &result, whence);
#else
#error "lseek and _llseek syscalls not available to perform a seek operation."
#endif
if (ret < 0)
return Error(-ret);
return result;
}
int close_func(File *f) {
auto *lf = reinterpret_cast<LinuxFile *>(f);
int ret = __llvm_libc::syscall_impl(SYS_close, lf->get_fd());
if (ret < 0) {
return -ret;
}
return 0;
}
int flush_func(File *f) {
auto *lf = reinterpret_cast<LinuxFile *>(f);
int ret = __llvm_libc::syscall_impl(SYS_fsync, lf->get_fd());
if (ret < 0) {
return -ret;
}
return 0;
}
} // anonymous namespace
ErrorOr<File *> openfile(const char *path, const char *mode) {
using ModeFlags = File::ModeFlags;
auto modeflags = File::mode_flags(mode);
if (modeflags == 0) {
// return {nullptr, EINVAL};
return Error(EINVAL);
}
long open_flags = 0;
if (modeflags & ModeFlags(File::OpenMode::APPEND)) {
open_flags = O_CREAT | O_APPEND;
if (modeflags & ModeFlags(File::OpenMode::PLUS))
open_flags |= O_RDWR;
else
open_flags |= O_WRONLY;
} else if (modeflags & ModeFlags(File::OpenMode::WRITE)) {
open_flags = O_CREAT | O_TRUNC;
if (modeflags & ModeFlags(File::OpenMode::PLUS))
open_flags |= O_RDWR;
else
open_flags |= O_WRONLY;
} else {
if (modeflags & ModeFlags(File::OpenMode::PLUS))
open_flags |= O_RDWR;
else
open_flags |= O_RDONLY;
}
// File created will have 0666 permissions.
constexpr long OPEN_MODE =
S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
#ifdef SYS_open
int fd = __llvm_libc::syscall_impl(SYS_open, path, open_flags, OPEN_MODE);
#elif defined(SYS_openat)
int fd = __llvm_libc::syscall_impl(SYS_openat, AT_FDCWD, path, open_flags,
OPEN_MODE);
#else
#error "open and openat syscalls not available."
#endif
if (fd < 0)
return Error(-fd);
uint8_t *buffer;
{
AllocChecker ac;
buffer = new (ac) uint8_t[File::DEFAULT_BUFFER_SIZE];
if (!ac)
return Error(ENOMEM);
}
AllocChecker ac;
auto *file = new (ac)
LinuxFile(fd, buffer, File::DEFAULT_BUFFER_SIZE, _IOFBF, true, modeflags);
if (!ac)
return Error(ENOMEM);
return file;
}
int get_fileno(File *f) {
auto *lf = reinterpret_cast<LinuxFile *>(f);
return lf->get_fd();
}
constexpr size_t STDIN_BUFFER_SIZE = 512;
uint8_t stdin_buffer[STDIN_BUFFER_SIZE];
static LinuxFile StdIn(0, stdin_buffer, STDIN_BUFFER_SIZE, _IOFBF, false,
File::ModeFlags(File::OpenMode::READ));
File *stdin = &StdIn;
constexpr size_t STDOUT_BUFFER_SIZE = 1024;
uint8_t stdout_buffer[STDOUT_BUFFER_SIZE];
static LinuxFile StdOut(1, stdout_buffer, STDOUT_BUFFER_SIZE, _IOLBF, false,
File::ModeFlags(File::OpenMode::APPEND));
File *stdout = &StdOut;
constexpr size_t STDERR_BUFFER_SIZE = 0;
static LinuxFile StdErr(2, nullptr, STDERR_BUFFER_SIZE, _IONBF, false,
File::ModeFlags(File::OpenMode::APPEND));
File *stderr = &StdErr;
} // namespace __llvm_libc
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