nativelibc/posix-io/read.c

/*	A part of the Native C Library for Windows NT
	Copyright 2007-2015 PC GO Ld.
	Copyright 2015-2018 Rivoreo

	This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
*/

#include <windows.h>
#include <nt.h>
#include <errno.h>
#include <unistd.h>
#include <ntstatus.h>
#include <wchar.h>

//#include <stdio.h>

int read(int fd, void *buffer, size_t count) {
	//printf("function: read(%d, %p, %u)\n", fd, buffer, count);
	if(!buffer) {
		errno = EFAULT;
		return -1;
	}
	if(!count) return 0;
#if 0
	if(fd == STDOUT_FILENO || fd == STDERR_FILENO) {
		errno = EBADF;
		return -1;
	}
#else
	if(IS_STD_PSEUDO_FD(fd)) {
		int real_fd = _get_std_fd(fd);
		switch(real_fd) {
			case TTY_FD_INVALID:
				errno = EBADF;
				return -1;
			case TTY_FD_DEFAULT:
				if(fd == STDIN_FILENO) return read_keyboard(buffer, count);
				errno = EBADF;	// read(2) on write-only fd (1 or 2)
				return -1;
		}
		fd = real_fd;
	}
#endif

	int is_file = 0;
	size_t oti_size = sizeof(OBJECT_TYPE_INFORMATION) + 64;
	OBJECT_TYPE_INFORMATION *oti = malloc(oti_size);
	if(!oti) return -1;
	long int status = NtQueryObject((void *)fd, ObjectTypeInformation, oti, oti_size, NULL);
	if(status < 0) {
		free(oti);
		__set_errno_from_ntstatus(status);
		return -1;
	}
	if(wcscmp(oti->TypeName.Buffer, L"Directory") == 0) {
		free(oti);
		errno = EISDIR;		// Directory object in OM
		return -1;
	}
	if(wcscmp(oti->TypeName.Buffer, L"File") == 0) is_file = 1;
	free(oti);

	IO_STATUS_BLOCK io_status;
	status = NtReadFile((void *)fd, NULL, NULL, NULL, &io_status, buffer, count, NULL, NULL);
	//printf("nativelibc debug: read: status = 0x%lx, is_file = %d\n", status, is_file);
	if(status == STATUS_END_OF_FILE) return 0;
	if(status == STATUS_INVALID_PARAMETER && is_file && count % 2 == 0) {
		if((unsigned long int)buffer % 4) errno = EFAULT;
		else errno = EISDIR;		// Directory file in FS
		return -1;
	}
	if(status < 0) {
		__set_errno_from_ntstatus(status);
		return -1;
	}
	return io_status.Information;
}