nativelibc/posix-io/access.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 <pathname.h>
#include <ntstatus.h>

//#include <stdio.h>

int access(const char *pathname, int mode) {
	if(mode & ~(R_OK | W_OK | X_OK | F_OK)) {
		errno = EINVAL;
		return -1;
	}
	if(!pathname) {
		errno = EFAULT;
		return -1;
	}
	if(!*pathname) {
		errno = ENOENT;
		return -1;
	}

	if(*pathname != '/') {
		errno = ENOSYS;
		return -1;
	}

	int request_dir = 0;
	UNICODE_STRING ntpathname;
	if(!RtlCreateUnicodeStringFromAsciiz(&ntpathname, pathname)) {
		errno = ENOMEM;
		return -1;
	}
	if(ntpathname.Length > sizeof(wchar_t) && ntpathname.Buffer[ntpathname.Length / sizeof(wchar_t) - 1] == L'/') {
		request_dir = 1;
		ntpathname.Buffer[ntpathname.Length / sizeof(wchar_t) - 1] = 0;
		ntpathname.Length -= sizeof(wchar_t);
		ntpathname.MaximumLength -= sizeof(wchar_t);
	}
	PATHNAME_UNIX2NT_UTF16_STRUCT(ntpathname);
	void *handle;
	OBJECT_ATTRIBUTES object_attrib = { sizeof(OBJECT_ATTRIBUTES), NULL, &ntpathname, 0, NULL, NULL };

	unsigned long int access_mask = DIRECTORY_QUERY;
	//if(mode & R_OK) access_mask |= DIRECTORY_QUERY;
	if(mode & W_OK) access_mask |= DIRECTORY_CREATE_OBJECT | DIRECTORY_CREATE_SUBDIRECTORY;
	if(mode & X_OK) access_mask |= DIRECTORY_TRAVERSE;
	long int status = NtOpenDirectoryObject(&handle, access_mask, &object_attrib);
	//printf("nativelibc debug: access: status = 0x%lx\n", status);
	// F_OK tests for the existence of the file
	if(mode == F_OK) switch(status) {
		case STATUS_INVALID_PARAMETER:
		case STATUS_NO_SUCH_DEVICE:
		case STATUS_NO_SUCH_FILE:
		case STATUS_WRONG_VOLUME:
		case STATUS_NO_MEDIA_IN_DEVICE:
		case STATUS_UNRECOGNIZED_MEDIA:
		case STATUS_NO_MEMORY:
		case STATUS_DISK_CORRUPT_ERROR:
		case STATUS_OBJECT_TYPE_MISMATCH:	// If the path is in FS, this status is returned
		case STATUS_OBJECT_NAME_INVALID:
		case STATUS_OBJECT_NAME_NOT_FOUND:
		case STATUS_OBJECT_PATH_INVALID:
		case STATUS_OBJECT_PATH_NOT_FOUND:
		case STATUS_OBJECT_PATH_SYNTAX_BAD:
		//case STATUS_OBJECT_NO_LONGER_EXISTS:
			break;
		default:
			RtlFreeUnicodeString(&ntpathname);
			if(status >= 0) NtClose(handle);
			return 0;
	}
	if(status != STATUS_OBJECT_TYPE_MISMATCH) {
		RtlFreeUnicodeString(&ntpathname);
		if(status >= 0) NtClose(handle);
		return __set_errno_from_ntstatus(status) ? -1 : 0;
	}

	if(request_dir) {
		ntpathname.Buffer[ntpathname.Length / sizeof(wchar_t)] = L'\\';
		ntpathname.Length += sizeof(wchar_t);
		ntpathname.MaximumLength += sizeof(wchar_t);
	}

	IO_STATUS_BLOCK io_status;
	unsigned long int file_share = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;
	unsigned long int options = FILE_SYNCHRONOUS_IO_NONALERT | FILE_OPEN_FOR_BACKUP_INTENT;
	access_mask = SYNCHRONIZE;
	if(mode & R_OK) access_mask |= GENERIC_READ | FILE_LIST_DIRECTORY;
	if(mode & W_OK) access_mask |= GENERIC_WRITE;
	if(mode & X_OK) access_mask |= FILE_TRAVERSE;		// Directory only
	status = NtOpenFile(&handle, access_mask, &object_attrib, &io_status, file_share, options);
	//printf("nativelibc debug: access: status = 0x%lx\n", status);
	RtlFreeUnicodeString(&ntpathname);
	if(status >= 0) NtClose(handle);
	return __set_errno_from_ntstatus(status) ? -1 : 0;
}