nativelibc/posix-io/chmod.c

/*	A part of the Native C Library for Windows NT
	Copyright 2007-2015 PC GO Ld.
	Copyright 2016-2026 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 <sys/stat.h>
#include <windows.h>
#include <nt.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <pathname.h>
#include <ntstatus.h>

//#include <stdio.h>

int fchmod(int fd, mode_t mode) {
	IO_STATUS_BLOCK io_status;
	FILE_BASIC_INFORMATION fbi;
	long int status = NtQueryInformationFile((void *)fd, &io_status, &fbi, sizeof fbi, FileBasicInformation);
	//printf("nativelibc debug: fchmod: status1 = 0x%lx\n", status);
	if(status < 0) {
		__set_errno_from_ntstatus(status);
		return -1;
	}

	if(mode & S_IWRITE) fbi.FileAttributes &= ~FILE_ATTRIBUTE_READONLY;
	else fbi.FileAttributes |= FILE_ATTRIBUTE_READONLY;

	status = NtSetInformationFile((void *)fd, &io_status, &fbi, sizeof fbi, FileBasicInformation);
	//printf("nativelibc debug: fchmod: status1 = 0x%lx\n", status);
	return __set_errno_from_ntstatus(status) ? -1 : 0;
}

int fchmodat(int dir_fd, const char *path, mode_t mode, int flags) {
	if(dir_fd == -1) {
		errno = EBADF;
		return -1;
	}
	if(!path) {
		errno = EFAULT;
		return -1;
	}
	if(flags & ~AT_SYMLINK_NOFOLLOW) {
		errno = EINVAL;
		return -1;
	}

	// We can't use open bacause we need to allow chmod a directory
	UNICODE_STRING ntpathname;
	if(!RtlCreateUnicodeStringFromAsciiz(&ntpathname, path)) {
		errno = ENOMEM;
		return -1;
	}
	PATHNAME_UNIX2NT_UTF16_STRUCT(ntpathname);
	OBJECT_ATTRIBUTES obj_attr = { .Length = sizeof(OBJECT_ATTRIBUTES), .ObjectName = &ntpathname };
	if(*path != '/') {
		if(dir_fd == AT_FDCWD) {
			RtlFreeUnicodeString(&ntpathname);
			errno = EPERM;
			return -1;
		}
		obj_attr.RootDirectory = (void *)dir_fd;
	}
	if(flags & AT_SYMLINK_NOFOLLOW) {
		void *handle;
		long int status = NtOpenSymbolicLinkObject(&handle, 0, &obj_attr);
		if(status >= 0 || status == STATUS_ACCESS_DENIED) {
			RtlFreeUnicodeString(&ntpathname);
			if(status >= 0) NtClose(handle);
			errno = ENOTSUP;
			return -1;
		}
	}
	void *fh;
	IO_STATUS_BLOCK io_status;
	unsigned long int access_mask = FILE_READ_EA | FILE_READ_ATTRIBUTES | FILE_WRITE_EA | FILE_WRITE_ATTRIBUTES | SYNCHRONIZE;
	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;
	long int status = NtOpenFile(&fh, access_mask, &obj_attr, &io_status, file_share, options);
	//printf("nativelibc debug: chmod: status = 0x%lx\n", status);
	RtlFreeUnicodeString(&ntpathname);
	if(status == STATUS_OBJECT_TYPE_MISMATCH) {
		errno = EPERM;
		return -1;
	}
	if(status < 0) {
		__set_errno_from_ntstatus(status);
		return -1;
	}
	int r = fchmod((int)fh, mode);
	status = NtClose(fh);
	if(r < 0) return r;
	if(status < 0) {
		__set_errno_from_ntstatus(status);
		return -1;
	}
	return r;
}

int chmod(const char *path, mode_t mode) {
	return fchmodat(AT_FDCWD, path, mode, 0);
}