2 Unix SMB/Netbios implementation.
4 kernel oplock processing for Linux
5 Copyright (C) Andrew Tridgell 2000
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 #if HAVE_KERNEL_OPLOCKS_LINUX
26 static VOLATILE sig_atomic_t signals_received;
27 static VOLATILE sig_atomic_t signals_processed;
28 static VOLATILE sig_atomic_t fd_pending; /* the fd of the current pending signal */
31 #define F_SETLEASE 1024
35 #define F_GETLEASE 1025
42 #ifndef RT_SIGNAL_LEASE
43 #define RT_SIGNAL_LEASE 33
50 /****************************************************************************
51 handle a LEASE signal, incrementing the signals_received and blocking the signal
52 ****************************************************************************/
53 static void signal_handler(int sig, siginfo_t *info, void *unused)
55 BlockSignals(True, sig);
56 fd_pending = (sig_atomic_t)info->si_fd;
61 /****************************************************************************
62 try to gain a linux capability
63 ****************************************************************************/
64 static void set_capability(unsigned capability)
66 #ifndef _LINUX_CAPABILITY_VERSION
67 #define _LINUX_CAPABILITY_VERSION 0x19980330
69 /* these can be removed when they are in glibc headers */
80 header.version = _LINUX_CAPABILITY_VERSION;
83 if (capget(&header, &data) == -1) {
84 DEBUG(3,("Unable to get kernel capabilities (%s)\n", strerror(errno)));
88 data.effective |= (1<<capability);
90 if (capset(&header, &data) == -1) {
91 DEBUG(3,("Unable to set %d capability (%s)\n",
92 capability, strerror(errno)));
97 /****************************************************************************
98 call SETLEASE. If we get EACCES then we try setting up the right capability and
100 ****************************************************************************/
101 static int linux_setlease(int fd, int leasetype)
105 if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
106 DEBUG(3,("Failed to set signal handler for kernel lease\n"));
110 ret = fcntl(fd, F_SETLEASE, leasetype);
111 if (ret == -1 && errno == EACCES) {
112 set_capability(CAP_LEASE);
113 ret = fcntl(fd, F_SETLEASE, leasetype);
120 /****************************************************************************
121 * Deal with the Linux kernel <--> smbd
122 * oplock break protocol.
123 ****************************************************************************/
124 static BOOL linux_oplock_receive_message(fd_set *fds, char *buffer, int buffer_len)
128 SMB_STRUCT_STAT sbuf;
131 if (signals_received == signals_processed) return False;
133 if (sys_fstat((int)fd_pending,&sbuf) == -1) {
134 DEBUG(0,("Invalid file descriptor %d in kernel oplock break!\n", (int)fd_pending));
142 DEBUG(3,("receive_local_message: kernel oplock break request received for \
143 dev = %x, inode = %.0f\n", (unsigned int)dev, (double)inode ));
146 * Create a kernel oplock break message.
149 /* Setup the message header */
150 SIVAL(buffer,OPBRK_CMD_LEN_OFFSET,KERNEL_OPLOCK_BREAK_MSG_LEN);
151 SSVAL(buffer,OPBRK_CMD_PORT_OFFSET,0);
153 buffer += OPBRK_CMD_HEADER_LEN;
155 SSVAL(buffer,OPBRK_MESSAGE_CMD_OFFSET,KERNEL_OPLOCK_BREAK_CMD);
157 memcpy(buffer + KERNEL_OPLOCK_BREAK_DEV_OFFSET, (char *)&dev, sizeof(dev));
158 memcpy(buffer + KERNEL_OPLOCK_BREAK_INODE_OFFSET, (char *)&inode, sizeof(inode));
161 /* now we can receive more signals */
162 fd_pending = (sig_atomic_t)-1;
164 BlockSignals(False, RT_SIGNAL_LEASE);
170 /****************************************************************************
171 Attempt to set an kernel oplock on a file.
172 ****************************************************************************/
173 static BOOL linux_set_kernel_oplock(files_struct *fsp, int oplock_type)
175 if (linux_setlease(fsp->fd, F_WRLCK) == -1) {
176 DEBUG(3,("set_file_oplock: Refused oplock on file %s, fd = %d, dev = %x, \
177 inode = %.0f. (%s)\n",
178 fsp->fsp_name, fsp->fd,
179 (unsigned int)fsp->dev, (double)fsp->inode, strerror(errno)));
183 DEBUG(3,("set_file_oplock: got kernel oplock on file %s, dev = %x, inode = %.0f\n",
184 fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode));
190 /****************************************************************************
191 Release a kernel oplock on a file.
192 ****************************************************************************/
193 static void linux_release_kernel_oplock(files_struct *fsp)
197 * Check and print out the current kernel
198 * oplock state of this file.
200 int state = fcntl(fsp->fd, F_GETLEASE, 0);
201 dbgtext("release_kernel_oplock: file %s, dev = %x, inode = %.0f has kernel \
202 oplock state of %x.\n", fsp->fsp_name, (unsigned int)fsp->dev,
203 (double)fsp->inode, state );
207 * Remove the kernel oplock on this file.
209 if (linux_setlease(fsp->fd, F_UNLCK) == -1) {
211 dbgtext("release_kernel_oplock: Error when removing kernel oplock on file " );
212 dbgtext("%s, dev = %x, inode = %.0f. Error was %s\n",
213 fsp->fsp_name, (unsigned int)fsp->dev,
214 (double)fsp->inode, strerror(errno) );
220 /****************************************************************************
221 parse a kernel oplock message
222 ****************************************************************************/
223 static BOOL linux_kernel_oplock_parse(char *msg_start, int msg_len, SMB_INO_T *inode, SMB_DEV_T *dev)
225 /* Ensure that the msg length is correct. */
226 if (msg_len != KERNEL_OPLOCK_BREAK_MSG_LEN) {
227 DEBUG(0,("incorrect length for KERNEL_OPLOCK_BREAK_CMD (was %d, should be %d).\n",
228 msg_len, KERNEL_OPLOCK_BREAK_MSG_LEN));
232 memcpy((char *)inode, msg_start+KERNEL_OPLOCK_BREAK_INODE_OFFSET, sizeof(*inode));
233 memcpy((char *)dev, msg_start+KERNEL_OPLOCK_BREAK_DEV_OFFSET, sizeof(*dev));
235 DEBUG(3,("kernel oplock break request for file dev = %x, inode = %.0f\n",
236 (unsigned int)*dev, (double)*inode));
242 /****************************************************************************
243 see if a oplock message is waiting
244 ****************************************************************************/
245 static BOOL linux_oplock_msg_waiting(fd_set *fds)
247 return signals_processed != signals_received;
250 /****************************************************************************
251 see if the kernel supports oplocks
252 ****************************************************************************/
253 static BOOL linux_oplocks_available(void)
256 fd = open("/dev/null", O_RDONLY);
257 if (fd == -1) return False; /* uggh! */
258 ret = fcntl(fd, F_GETLEASE, 0);
260 return ret == F_UNLCK;
264 /****************************************************************************
266 ****************************************************************************/
267 struct kernel_oplocks *linux_init_kernel_oplocks(void)
269 static struct kernel_oplocks koplocks;
270 struct sigaction act;
272 if (!linux_oplocks_available()) {
273 DEBUG(3,("Linux kernel oplocks not available\n"));
277 act.sa_handler = NULL;
278 act.sa_sigaction = signal_handler;
279 act.sa_flags = SA_SIGINFO;
280 if (sigaction(RT_SIGNAL_LEASE, &act, NULL) != 0) {
281 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler\n"));
285 koplocks.receive_message = linux_oplock_receive_message;
286 koplocks.set_oplock = linux_set_kernel_oplock;
287 koplocks.release_oplock = linux_release_kernel_oplock;
288 koplocks.parse_message = linux_kernel_oplock_parse;
289 koplocks.msg_waiting = linux_oplock_msg_waiting;
290 koplocks.notification_fd = -1;
292 DEBUG(3,("Linux kernel oplocks enabled\n"));
300 void oplock_linux_dummy(void) {}
301 #endif /* HAVE_KERNEL_OPLOCKS_LINUX */