nativelibc/posix-io/read.c

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

	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>

int read(int fd, void *buffer, size_t count) {
	if(!buffer) {
		errno = EFAULT;
		return -1;
	}
	if(!count) return 0;
	if(fd == STDOUT_FILENO || fd == STDERR_FILENO) {
		errno = EINVAL;
		return -1;
	}

	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\n", status);
	if(status == STATUS_END_OF_FILE) return 0;
	if(status == STATUS_INVALID_PARAMETER && is_file) {
		errno = EISDIR;		// Directory file in FS
		return -1;
	}
	if(__set_errno_from_ntstatus(status)) return -1;
	return io_status.Information;
}