open.c

samba-3.0.22.tar.gz 编译smb服务器的源码

	return True;

}

/* Map generic permissions to file object specific permissions */
                                                                                                               
struct generic_mapping file_generic_mapping = {
	FILE_GENERIC_READ,
	FILE_GENERIC_WRITE,
	FILE_GENERIC_EXECUTE,
	FILE_GENERIC_ALL
};

/****************************************************************************
 Open a file with a share mode.
****************************************************************************/

files_struct *open_file_ntcreate(connection_struct *conn,
				 const char *fname,
				 SMB_STRUCT_STAT *psbuf,
				 uint32 access_mask,		/* access bits (FILE_READ_DATA etc.) */
				 uint32 share_access,		/* share constants (FILE_SHARE_READ etc). */
				 uint32 create_disposition,	/* FILE_OPEN_IF etc. */
				 uint32 create_options,		/* options such as delete on close. */
				 uint32 new_dos_attributes,	/* attributes used for new file. */
				 int oplock_request, 		/* internal Samba oplock codes. */
				 				/* Information (FILE_EXISTS etc.) */
				 int *pinfo)
{
	int flags=0;
	int flags2=0;
	BOOL file_existed = VALID_STAT(*psbuf);
	BOOL def_acl = False;
	BOOL internal_only_open = False;
	SMB_DEV_T dev = 0;
	SMB_INO_T inode = 0;
	BOOL fsp_open = False;
	files_struct *fsp = NULL;
	mode_t new_unx_mode = (mode_t)0;
	mode_t unx_mode = (mode_t)0;
	int info;
	uint32 existing_dos_attributes = 0;
	struct pending_message_list *pml = NULL;
	uint16 mid = get_current_mid();
	BOOL delayed_for_oplocks = False;
	struct timeval request_time = timeval_zero();
	struct share_mode_lock *lck = NULL;
	NTSTATUS status;

	if (conn->printer) {
		/* 
		 * Printers are handled completely differently.
		 * Most of the passed parameters are ignored.
		 */

		if (pinfo) {
			*pinfo = FILE_WAS_CREATED;
		}

		DEBUG(10, ("open_file_ntcreate: printer open fname=%s\n", fname));

		return print_fsp_open(conn, fname);
	}

	/* We add aARCH to this as this mode is only used if the file is
	 * created new. */
	unx_mode = unix_mode(conn, new_dos_attributes | aARCH,fname, True);

	DEBUG(10, ("open_file_ntcreate: fname=%s, dos_attrs=0x%x "
		   "access_mask=0x%x share_access=0x%x "
		   "create_disposition = 0x%x create_options=0x%x "
		   "unix mode=0%o oplock_request=%d\n",
		   fname, new_dos_attributes, access_mask, share_access,
		   create_disposition, create_options, unx_mode,
		   oplock_request));

	if (oplock_request == INTERNAL_OPEN_ONLY) {
		internal_only_open = True;
		oplock_request = 0;
	}

	if ((pml = get_open_deferred_message(mid)) != NULL) {
		struct deferred_open_record *state =
			(struct deferred_open_record *)pml->private_data.data;

		request_time = pml->request_time;
		delayed_for_oplocks = state->delayed_for_oplocks;

		/* There could be a race condition where the dev/inode pair
		   has changed since we deferred the message. If so, just
		   remove the deferred open entry and return sharing
		   violation. */

		/* If the timeout value is non-zero, we need to just return
		   sharing violation. Don't retry the open as we were not
		   notified of a close and we don't want to trigger another
		   spurious oplock break. */

		/* Now remove the deferred open entry under lock. */
		lck = get_share_mode_lock(NULL, state->dev, state->inode, NULL, NULL);
		if (lck == NULL) {
			DEBUG(0, ("could not get share mode lock\n"));
		} else {
			del_deferred_open_entry(lck, mid);
			talloc_destroy(lck);
		}

		/* Ensure we don't reprocess this message. */
		remove_deferred_open_smb_message(mid);
	}

	if (!check_name(fname,conn)) {
		return NULL;
	} 

	new_dos_attributes &= SAMBA_ATTRIBUTES_MASK;
	if (file_existed) {
		existing_dos_attributes = dos_mode(conn, fname, psbuf);
	}

	/* ignore any oplock requests if oplocks are disabled */
	if (!lp_oplocks(SNUM(conn)) || global_client_failed_oplock_break ||
	    IS_VETO_OPLOCK_PATH(conn, fname)) {
		oplock_request = 0;
	}

	/* this is for OS/2 long file names - say we don't support them */
	if (!lp_posix_pathnames() && strstr(fname,".+,;=[].")) {
		/* OS/2 Workplace shell fix may be main code stream in a later
		 * release. */ 
		set_saved_error_triple(ERRDOS, ERRcannotopen,
				       NT_STATUS_OBJECT_NAME_NOT_FOUND);
		DEBUG(5,("open_file_ntcreate: OS/2 long filenames are not "
			 "supported.\n"));
		return NULL;
	}

	switch( create_disposition ) {
		/*
		 * Currently we're using FILE_SUPERSEDE as the same as
		 * FILE_OVERWRITE_IF but they really are
		 * different. FILE_SUPERSEDE deletes an existing file
		 * (requiring delete access) then recreates it.
		 */
		case FILE_SUPERSEDE:
			/* If file exists replace/overwrite. If file doesn't
			 * exist create. */
			flags2 |= (O_CREAT | O_TRUNC);
			break;

		case FILE_OVERWRITE_IF:
			/* If file exists replace/overwrite. If file doesn't
			 * exist create. */
			flags2 |= (O_CREAT | O_TRUNC);
			break;

		case FILE_OPEN:
			/* If file exists open. If file doesn't exist error. */
			if (!file_existed) {
				DEBUG(5,("open_file_ntcreate: FILE_OPEN "
					 "requested for file %s and file "
					 "doesn't exist.\n", fname ));
				set_saved_ntstatus(NT_STATUS_OBJECT_NAME_NOT_FOUND);
				errno = ENOENT;
				return NULL;
			}
			break;

		case FILE_OVERWRITE:
			/* If file exists overwrite. If file doesn't exist
			 * error. */
			if (!file_existed) {
				DEBUG(5,("open_file_ntcreate: FILE_OVERWRITE "
					 "requested for file %s and file "
					 "doesn't exist.\n", fname ));
				set_saved_ntstatus(NT_STATUS_OBJECT_NAME_NOT_FOUND);
				errno = ENOENT;
				return NULL;
			}
			flags2 |= O_TRUNC;
			break;

		case FILE_CREATE:
			/* If file exists error. If file doesn't exist
			 * create. */
			if (file_existed) {
				DEBUG(5,("open_file_ntcreate: FILE_CREATE "
					 "requested for file %s and file "
					 "already exists.\n", fname ));
				if (S_ISDIR(psbuf->st_mode)) {
					errno = EISDIR;
				} else {
					errno = EEXIST;
				}
				return NULL;
			}
			flags2 |= (O_CREAT|O_EXCL);
			break;

		case FILE_OPEN_IF:
			/* If file exists open. If file doesn't exist
			 * create. */
			flags2 |= O_CREAT;
			break;

		default:
			set_saved_ntstatus(NT_STATUS_INVALID_PARAMETER);
			return NULL;
	}

	/* We only care about matching attributes on file exists and
	 * overwrite. */

	if (file_existed && ((create_disposition == FILE_OVERWRITE) ||
			     (create_disposition == FILE_OVERWRITE_IF))) {
		if (!open_match_attributes(conn, fname,
					   existing_dos_attributes,
					   new_dos_attributes, psbuf->st_mode,
					   unx_mode, &new_unx_mode)) {
			DEBUG(5,("open_file_ntcreate: attributes missmatch "
				 "for file %s (%x %x) (0%o, 0%o)\n",
				 fname, existing_dos_attributes,
				 new_dos_attributes,
				 (unsigned int)psbuf->st_mode,
				 (unsigned int)unx_mode ));
			errno = EACCES;
			return NULL;
		}
	}

	/* This is a nasty hack - must fix... JRA. */
	if (access_mask == MAXIMUM_ALLOWED_ACCESS) {
		access_mask = FILE_GENERIC_ALL;
	}

	/*
	 * Convert GENERIC bits to specific bits.
	 */

	se_map_generic(&access_mask, &file_generic_mapping);

	DEBUG(10, ("open_file_ntcreate: fname=%s, after mapping "
		   "access_mask=0x%x\n", fname, access_mask ));

	/*
	 * Note that we ignore the append flag as append does not
	 * mean the same thing under DOS and Unix.
	 */

	if (access_mask & (FILE_WRITE_DATA | FILE_APPEND_DATA)) {
		flags = O_RDWR;
	} else {
		flags = O_RDONLY;
	}

	/*
	 * Currently we only look at FILE_WRITE_THROUGH for create options.
	 */

#if defined(O_SYNC)
	if (create_options & FILE_WRITE_THROUGH) {
		flags2 |= O_SYNC;
	}
#endif /* O_SYNC */
  
	if (!CAN_WRITE(conn)) {
		/*
		 * We should really return a permission denied error if either
		 * O_CREAT or O_TRUNC are set, but for compatibility with
		 * older versions of Samba we just AND them out.
		 */
		flags2 &= ~(O_CREAT|O_TRUNC);
	}

	/*
	 * Ensure we can't write on a read-only share or file.
	 */

	if (flags != O_RDONLY && file_existed &&
	    (!CAN_WRITE(conn) || IS_DOS_READONLY(existing_dos_attributes))) {
		DEBUG(5,("open_file_ntcreate: write access requested for "
			 "file %s on read only %s\n",
			 fname, !CAN_WRITE(conn) ? "share" : "file" ));
		set_saved_ntstatus(NT_STATUS_ACCESS_DENIED);
		errno = EACCES;
		return NULL;
	}

	fsp = file_new(conn);
	if(!fsp) {
		return NULL;
	}

	fsp->dev = psbuf->st_dev;
	fsp->inode = psbuf->st_ino;
	fsp->share_access = share_access;
	fsp->fh->private_options = create_options;
	fsp->access_mask = access_mask;
	fsp->oplock_type = oplock_request;

	if (timeval_is_zero(&request_time)) {
		request_time = fsp->open_time;
	}

	if (file_existed) {

		dev = psbuf->st_dev;
		inode = psbuf->st_ino;

		lck = get_share_mode_lock(NULL, dev, inode,
					conn->connectpath,
					fname);

		if (lck == NULL) {
			DEBUG(0, ("Could not get share mode lock\n"));
			set_saved_ntstatus(NT_STATUS_SHARING_VIOLATION);
			return NULL;
		}

		if (delay_for_oplocks(lck, fsp)) {
			struct deferred_open_record state;
			struct timeval timeout;

			if (delayed_for_oplocks) {
				DEBUG(0, ("Trying to delay for oplocks "
					  "twice\n"));
				exit_server("exiting");
			}

			timeout = timeval_set(OPLOCK_BREAK_TIMEOUT*2, 0);

			/* Normally the smbd we asked should respond within
			 * OPLOCK_BREAK_TIMEOUT seconds regardless of whether
			 * the client did, give twice the timeout as a safety
			 * measure here in case the other smbd is stuck
			 * somewhere else. */

			state.delayed_for_oplocks = True;
			state.dev = dev;
			state.inode = inode;

			if (!request_timed_out(request_time, timeout)) {
				defer_open(lck, request_time, timeout,
					   &state);
			}

			talloc_free(lck);
			return NULL;
		}

		status = open_mode_check(conn, fname, lck,
					 access_mask, share_access,
					 create_options, &file_existed);

		if (NT_STATUS_EQUAL(status, NT_STATUS_DELETE_PENDING)) {
			/* DELETE_PENDING is not deferred for a second */
			set_saved_ntstatus(status);
			talloc_free(lck);
			file_free(fsp);
			return NULL;
		}

		if (!NT_STATUS_IS_OK(status)) {

			SMB_ASSERT(NT_STATUS_EQUAL(status, NT_STATUS_SHARING_VIOLATION));

			/* Check if this can be done with the deny_dos and fcb
			 * calls. */
			if (create_options &
			    (NTCREATEX_OPTIONS_PRIVATE_DENY_DOS|
			     NTCREATEX_OPTIONS_PRIVATE_DENY_FCB)) {
				files_struct *fsp_dup;
				fsp_dup = fcb_or_dos_open(conn, fname, dev,
							  inode, access_mask,
							  share_access,
							  create_options);

				if (fsp_dup) {
					talloc_free(lck);
					file_free(fsp);
					if (pinfo) {
						*pinfo = FILE_WAS_OPENED;
					}
					conn->num_files_open++;
					return fsp_dup;
				}
			}

			/*
			 * This next line is a subtlety we need for
			 * MS-Access. If a file open will fail due to share
			 * permissions and also for security (access) reasons,
			 * we need to return the access failed error, not the
			 * share error. This means we must attempt to open the
			 * file anyway in order to get the UNIX access error -
			 * even if we're going to fail the open for share
			 * reasons. This is bad, as we're burning another fd
			 * if there are existing locks but there's nothing
			 * else we can do. We also ensure we're not going to
			 * create or tuncate the file as we only want an
			 * access decision at this stage. JRA.
			 */
			errno = 0;
			fsp_open = open_file(fsp,conn,fname,psbuf,
					     flags|(flags2&~(O_TRUNC|O_CREAT)),
					     unx_mode,access_mask);

			DEBUG(4,("open_file_ntcreate : share_mode deny - "
				 "calling open_file with flags=0x%X "
				 "flags2=0x%X mode=0%o returned %d\n",
				 flags, (flags2&~(O_TRUNC|O_CREAT)),
				 (unsigned int)unx_mode, (int)fsp_open ));

			if (!fsp_open && errno) {
				/* Default error. */
				set_saved_ntstatus(NT_STATUS_ACCESS_DENIED);
			}

			/* 
			 * If we're returning a share violation, ensure we
			 * cope with the braindead 1 second delay.
			 */

			if (!internal_only_open &&
			    lp_defer_sharing_violations()) {
				struct timeval timeout;
				struct deferred_open_record state;

				timeout = timeval_set(0, SHARING_VIOLATION_USEC_WAIT);

				state.delayed_for_oplocks = False;
				state.dev = dev;
				state.inode = inode;

				if (!request_timed_out(request_time,
						       timeout)) {
					defer_open(lck, request_time, timeout,
						   &state);
				}
			}

			talloc_free(lck);
			if (fsp_open) {
				fd_close(conn, fsp);
				/*
				 * We have detected a sharing violation here
				 * so return the correct error code
				 */
				set_saved_ntstatus(NT_STATUS_SHARING_VIOLATION);
			}
			file_free(fsp);
			return NULL;
		}

		/*
		 * We exit this block with the share entry *locked*.....
		 */
	}

	SMB_ASSERT(!file_existed || (lck != NULL));

	/*
	 * Ensure we pay attention to default ACLs on directories if required.
	 */

        if ((flags2 & O_CREAT) && lp_inherit_acls(SNUM(conn)) &&
	    (def_acl = directory_has_default_acl(conn,
						 parent_dirname(fname)))) {
		unx_mode = 0777;
	}

	DEBUG(4,("calling open_file with flags=0x%X flags2=0x%X mode=0%o\n",
		 (unsigned int)flags, (unsigned int)flags2,
		 (unsigned int)unx_mode));

	/*
	 * open_file strips any O_TRUNC flags itself.
	 */

	fsp_open = open_file(fsp,conn,fname,psbuf,flags|flags2,unx_mode,
			     access_mask);

	if (!fsp_open) {
		if (lck != NULL) {
			talloc_free(lck);
		}
		file_free(fsp);
		return NULL;
	}

	if (!file_existed) { 

		/*
		 * Deal with the race condition where two smbd's detect the
		 * file doesn't exist and do the create at the same time. One
		 * of them will win and set a share mode, the other (ie. this
		 * one) should check if the requested share mode for this
		 * create is allowed.
		 */

		/*
		 * Now the file exists and fsp is successfully opened,
		 * fsp->dev and fsp->inode are valid and should replace the
		 * dev=0,inode=0 from a non existent file. Spotted by
		 * Nadav Danieli <[e-mail]>. JRA.
		 */

		dev = fsp->dev;