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 extern int DEBUGLEVEL;
28 static VOLATILE SIG_ATOMIC_T signals_received;
29 static VOLATILE SIG_ATOMIC_T signals_processed;
30 static VOLATILE SIG_ATOMIC_T fd_pending; /* the fd of the current pending signal */
33 #define F_SETLEASE 1024
37 #define F_GETLEASE 1025
44 #ifndef RT_SIGNAL_LEASE
45 #define RT_SIGNAL_LEASE 33
52 /****************************************************************************
53 handle a LEASE signal, incrementing the signals_received and blocking the signal
54 ****************************************************************************/
55 static void signal_handler(int signal, siginfo_t *info, void *unused)
57 BlockSignals(True, signal);
58 fd_pending = (SIG_ATOMIC_T)info->si_fd;
63 /****************************************************************************
64 try to gain a linux capability
65 ****************************************************************************/static void set_capability(unsigned capability)
67 #ifndef _LINUX_CAPABILITY_VERSION
68 #define _LINUX_CAPABILITY_VERSION 0x19980330
70 /* these can be removed when they are in glibc headers */
81 header.version = _LINUX_CAPABILITY_VERSION;
84 if (capget(&header, &data) == -1) {
85 DEBUG(3,("Unable to get kernel capabilities (%s)\n", strerror(errno)));
89 data.effective |= (1<<capability);
91 if (capset(&header, &data) == -1) {
92 DEBUG(3,("Unable to set %d capability (%s)\n",
93 capability, strerror(errno)));
98 /****************************************************************************
99 call SETLEASE. If we get EACCES then we try setting up the right capability and
101 ****************************************************************************/
102 static int linux_setlease(int fd, int leasetype)
106 if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
107 DEBUG(3,("Failed to set signal handler for kernel lease\n"));
111 ret = fcntl(fd, F_SETLEASE, leasetype);
112 if (ret == -1 && errno == EACCES) {
113 set_capability(CAP_LEASE);
114 ret = fcntl(fd, F_SETLEASE, leasetype);
121 /****************************************************************************
122 * Deal with the Linux kernel <--> smbd
123 * oplock break protocol.
124 ****************************************************************************/
125 static BOOL linux_oplock_receive_message(fd_set *fds, char *buffer, int buffer_len)
129 SMB_STRUCT_STAT sbuf;
132 if (signals_received == signals_processed) return False;
134 if (sys_fstat((int)fd_pending,&sbuf) == -1) {
135 DEBUG(0,("Invalid file descriptor %d in kernel oplock break!\n", (int)fd_pending));
143 DEBUG(3,("receive_local_message: kernel oplock break request received for \
144 dev = %x, inode = %.0f\n", (unsigned int)dev, (double)inode ));
147 * Create a kernel oplock break message.
150 /* Setup the message header */
151 SIVAL(buffer,OPBRK_CMD_LEN_OFFSET,KERNEL_OPLOCK_BREAK_MSG_LEN);
152 SSVAL(buffer,OPBRK_CMD_PORT_OFFSET,0);
154 buffer += OPBRK_CMD_HEADER_LEN;
156 SSVAL(buffer,OPBRK_MESSAGE_CMD_OFFSET,KERNEL_OPLOCK_BREAK_CMD);
158 memcpy(buffer + KERNEL_OPLOCK_BREAK_DEV_OFFSET, (char *)&dev, sizeof(dev));
159 memcpy(buffer + KERNEL_OPLOCK_BREAK_INODE_OFFSET, (char *)&inode, sizeof(inode));
162 /* now we can receive more signals */
163 fd_pending = (SIG_ATOMIC_T)-1;
165 BlockSignals(False, RT_SIGNAL_LEASE);
171 /****************************************************************************
172 Attempt to set an kernel oplock on a file.
173 ****************************************************************************/
174 static BOOL linux_set_kernel_oplock(files_struct *fsp, int oplock_type)
176 if (linux_setlease(fsp->fd, F_WRLCK) == -1) {
177 DEBUG(3,("set_file_oplock: Refused oplock on file %s, fd = %d, dev = %x, \
178 inode = %.0f. (%s)\n",
179 fsp->fsp_name, fsp->fd,
180 (unsigned int)fsp->dev, (double)fsp->inode, strerror(errno)));
184 DEBUG(3,("set_file_oplock: got kernel oplock on file %s, dev = %x, inode = %.0f\n",
185 fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode));
191 /****************************************************************************
192 Release a kernel oplock on a file.
193 ****************************************************************************/
194 static void linux_release_kernel_oplock(files_struct *fsp)
198 * Check and print out the current kernel
199 * oplock state of this file.
201 int state = fcntl(fsp->fd, F_GETLEASE, 0);
202 dbgtext("release_kernel_oplock: file %s, dev = %x, inode = %.0f has kernel \
203 oplock state of %x.\n", fsp->fsp_name, (unsigned int)fsp->dev,
204 (double)fsp->inode, state );
208 * Remove the kernel oplock on this file.
210 if (linux_setlease(fsp->fd, F_UNLCK) == -1) {
212 dbgtext("release_kernel_oplock: Error when removing kernel oplock on file " );
213 dbgtext("%s, dev = %x, inode = %.0f. Error was %s\n",
214 fsp->fsp_name, (unsigned int)fsp->dev,
215 (double)fsp->inode, strerror(errno) );
221 /****************************************************************************
222 parse a kernel oplock message
223 ****************************************************************************/
224 static BOOL linux_kernel_oplock_parse(char *msg_start, int msg_len, SMB_INO_T *inode, SMB_DEV_T *dev)
226 /* Ensure that the msg length is correct. */
227 if (msg_len != KERNEL_OPLOCK_BREAK_MSG_LEN) {
228 DEBUG(0,("incorrect length for KERNEL_OPLOCK_BREAK_CMD (was %d, should be %d).\n",
229 msg_len, KERNEL_OPLOCK_BREAK_MSG_LEN));
233 memcpy((char *)inode, msg_start+KERNEL_OPLOCK_BREAK_INODE_OFFSET, sizeof(*inode));
234 memcpy((char *)dev, msg_start+KERNEL_OPLOCK_BREAK_DEV_OFFSET, sizeof(*dev));
236 DEBUG(3,("kernel oplock break request for file dev = %x, inode = %.0f\n",
237 (unsigned int)*dev, (double)*inode));
243 /****************************************************************************
244 see if a oplock message is waiting
245 ****************************************************************************/
246 static BOOL linux_oplock_msg_waiting(fd_set *fds)
248 return signals_processed != signals_received;
251 /****************************************************************************
252 see if the kernel supports oplocks
253 ****************************************************************************/
254 static BOOL linux_oplocks_available(void)
257 fd = open("/dev/null", O_RDONLY);
258 if (fd == -1) return False; /* uggh! */
259 ret = fcntl(fd, F_GETLEASE, 0);
261 return ret == F_UNLCK;
265 /****************************************************************************
267 ****************************************************************************/
268 struct kernel_oplocks *linux_init_kernel_oplocks(void)
270 static struct kernel_oplocks koplocks;
271 struct sigaction act;
273 if (!linux_oplocks_available()) {
274 DEBUG(3,("Linux kernel oplocks not available\n"));
278 act.sa_handler = NULL;
279 act.sa_sigaction = signal_handler;
280 act.sa_flags = SA_SIGINFO;
281 if (sigaction(RT_SIGNAL_LEASE, &act, NULL) != 0) {
282 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler\n"));
286 koplocks.receive_message = linux_oplock_receive_message;
287 koplocks.set_oplock = linux_set_kernel_oplock;
288 koplocks.release_oplock = linux_release_kernel_oplock;
289 koplocks.parse_message = linux_kernel_oplock_parse;
290 koplocks.msg_waiting = linux_oplock_msg_waiting;
291 koplocks.notification_fd = -1;
293 DEBUG(3,("Linux kernel oplocks enabled\n"));
301 void oplock_linux_dummy(void) {}
302 #endif /* HAVE_KERNEL_OPLOCKS_LINUX */