Function Pwrite64

pkg/sentry/syscalls/linux/sys_read_write.go:375–407

Pwrite64 implements Linux syscall pwrite64(2).

(t *kernel.Task, sysno uintptr, args arch.SyscallArguments)

// Pwrite64 implements Linux syscall pwrite64(2).
func Pwrite64(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
	fd := args[0].Int()
	addr := args[1].Pointer()
	size := args[2].SizeT()
	offset := args[3].Int64()

	file := t.GetFile(fd)
	if file == nil {
		return 0, nil, linuxerr.EBADF
	}
	defer file.DecRef(t)

	// Check that the offset is legitimate and does not overflow.
	if offset < 0 || offset+int64(size) < 0 {
		return 0, nil, linuxerr.EINVAL
	}

	// Check that the size is legitimate.
	si := int(size)
	if si < 0 {
		return 0, nil, linuxerr.EINVAL
	}

	// Get the source of the write.
	src, err := t.SingleIOSequence(addr, si, usermem.IOOpts{})
	if err != nil {
		return 0, nil, err
	}

	n, err := pwrite(t, file, src, offset, vfs.WriteOptions{})
	t.IOUsage().AccountWriteSyscall(n)
	return uintptr(n), nil, HandleIOError(t, n != 0, err, linuxerr.ERESTARTSYS, "pwrite64", file)
}

// Pwritev implements Linux syscall pwritev(2).
func Pwritev(t *kernel.Task, sysno uintptr, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {