2 Unix SMB/CIFS implementation.
3 kernel oplock processing for Linux
4 Copyright (C) Andrew Tridgell 2000
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 #if HAVE_KERNEL_OPLOCKS_LINUX
25 static SIG_ATOMIC_T signals_received;
26 #define FD_PENDING_SIZE 100
27 static SIG_ATOMIC_T fd_pending_array[FD_PENDING_SIZE];
30 #define F_SETLEASE 1024
34 #define F_GETLEASE 1025
41 #ifndef RT_SIGNAL_LEASE
42 #define RT_SIGNAL_LEASE (SIGRTMIN+1)
49 /****************************************************************************
50 Handle a LEASE signal, incrementing the signals_received and blocking the signal.
51 ****************************************************************************/
53 static void signal_handler(int sig, siginfo_t *info, void *unused)
55 if (signals_received < FD_PENDING_SIZE - 1) {
56 fd_pending_array[signals_received] = (SIG_ATOMIC_T)info->si_fd;
58 } /* Else signal is lost. */
62 /****************************************************************************
63 Try to gain a linux capability.
64 ****************************************************************************/
66 static void set_capability(unsigned capability)
68 #ifndef _LINUX_CAPABILITY_VERSION
69 #define _LINUX_CAPABILITY_VERSION 0x19980330
71 /* these can be removed when they are in glibc headers */
72 struct cap_user_header {
76 struct cap_user_data {
82 extern int capget(struct cap_user_header * hdrp,
83 struct cap_user_data * datap);
84 extern int capset(struct cap_user_header * hdrp,
85 const struct cap_user_data * datap);
87 header.version = _LINUX_CAPABILITY_VERSION;
90 if (capget(&header, &data) == -1) {
91 DEBUG(3,("Unable to get kernel capabilities (%s)\n", strerror(errno)));
95 data.effective |= (1<<capability);
97 if (capset(&header, &data) == -1) {
98 DEBUG(3,("Unable to set %d capability (%s)\n",
99 capability, strerror(errno)));
103 /****************************************************************************
104 Call SETLEASE. If we get EACCES then we try setting up the right capability and
106 ****************************************************************************/
108 static int linux_setlease(int fd, int leasetype)
112 if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
113 DEBUG(3,("Failed to set signal handler for kernel lease\n"));
117 ret = fcntl(fd, F_SETLEASE, leasetype);
118 if (ret == -1 && errno == EACCES) {
119 set_capability(CAP_LEASE);
120 ret = fcntl(fd, F_SETLEASE, leasetype);
126 /****************************************************************************
127 * Deal with the Linux kernel <--> smbd
128 * oplock break protocol.
129 ****************************************************************************/
131 static BOOL linux_oplock_receive_message(fd_set *fds, char *buffer, int buffer_len)
134 struct files_struct *fsp;
136 BlockSignals(True, RT_SIGNAL_LEASE);
137 fd = fd_pending_array[0];
138 fsp = file_find_fd(fd);
139 fd_pending_array[0] = (SIG_ATOMIC_T)-1;
140 if (signals_received > 1)
141 memmove(CONST_DISCARD(void *, &fd_pending_array[0]),
142 CONST_DISCARD(void *, &fd_pending_array[1]),
143 sizeof(SIG_ATOMIC_T)*(signals_received-1));
145 /* now we can receive more signals */
146 BlockSignals(False, RT_SIGNAL_LEASE);
149 DEBUG(0,("Invalid file descriptor %d in kernel oplock break!\n", (int)fd));
153 DEBUG(3,("linux_oplock_receive_message: kernel oplock break request received for \
154 dev = %x, inode = %.0f fd = %d, fileid = %lu \n", (unsigned int)fsp->dev, (double)fsp->inode,
158 * Create a kernel oplock break message.
161 /* Setup the message header */
162 SIVAL(buffer,OPBRK_CMD_LEN_OFFSET,KERNEL_OPLOCK_BREAK_MSG_LEN);
163 SSVAL(buffer,OPBRK_CMD_PORT_OFFSET,0);
165 buffer += OPBRK_CMD_HEADER_LEN;
167 SSVAL(buffer,OPBRK_MESSAGE_CMD_OFFSET,KERNEL_OPLOCK_BREAK_CMD);
169 memcpy(buffer + KERNEL_OPLOCK_BREAK_DEV_OFFSET, (char *)&fsp->dev, sizeof(fsp->dev));
170 memcpy(buffer + KERNEL_OPLOCK_BREAK_INODE_OFFSET, (char *)&fsp->inode, sizeof(fsp->inode));
171 memcpy(buffer + KERNEL_OPLOCK_BREAK_FILEID_OFFSET, (char *)&fsp->file_id, sizeof(fsp->file_id));
176 /****************************************************************************
177 Attempt to set an kernel oplock on a file.
178 ****************************************************************************/
180 static BOOL linux_set_kernel_oplock(files_struct *fsp, int oplock_type)
182 if (linux_setlease(fsp->fd, F_WRLCK) == -1) {
183 DEBUG(3,("linux_set_kernel_oplock: Refused oplock on file %s, fd = %d, dev = %x, \
184 inode = %.0f. (%s)\n",
185 fsp->fsp_name, fsp->fd,
186 (unsigned int)fsp->dev, (double)fsp->inode, strerror(errno)));
190 DEBUG(3,("linux_set_kernel_oplock: got kernel oplock on file %s, dev = %x, inode = %.0f, file_id = %lu\n",
191 fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode, fsp->file_id));
196 /****************************************************************************
197 Release a kernel oplock on a file.
198 ****************************************************************************/
200 static void linux_release_kernel_oplock(files_struct *fsp)
204 * Check and print out the current kernel
205 * oplock state of this file.
207 int state = fcntl(fsp->fd, F_GETLEASE, 0);
208 dbgtext("linux_release_kernel_oplock: file %s, dev = %x, inode = %.0f file_id = %lu has kernel \
209 oplock state of %x.\n", fsp->fsp_name, (unsigned int)fsp->dev,
210 (double)fsp->inode, fsp->file_id, state );
214 * Remove the kernel oplock on this file.
216 if (linux_setlease(fsp->fd, F_UNLCK) == -1) {
218 dbgtext("linux_release_kernel_oplock: Error when removing kernel oplock on file " );
219 dbgtext("%s, dev = %x, inode = %.0f, file_id = %lu. Error was %s\n",
220 fsp->fsp_name, (unsigned int)fsp->dev,
221 (double)fsp->inode, fsp->file_id, strerror(errno) );
226 /****************************************************************************
227 Parse a kernel oplock message.
228 ****************************************************************************/
230 static BOOL linux_kernel_oplock_parse(char *msg_start, int msg_len, SMB_INO_T *inode,
231 SMB_DEV_T *dev, unsigned long *file_id)
233 /* Ensure that the msg length is correct. */
234 if (msg_len != KERNEL_OPLOCK_BREAK_MSG_LEN) {
235 DEBUG(0,("incorrect length for KERNEL_OPLOCK_BREAK_CMD (was %d, should be %lu).\n",
236 msg_len, (unsigned long)KERNEL_OPLOCK_BREAK_MSG_LEN));
240 memcpy((char *)inode, msg_start+KERNEL_OPLOCK_BREAK_INODE_OFFSET, sizeof(*inode));
241 memcpy((char *)dev, msg_start+KERNEL_OPLOCK_BREAK_DEV_OFFSET, sizeof(*dev));
242 memcpy((char *)file_id, msg_start+KERNEL_OPLOCK_BREAK_FILEID_OFFSET, sizeof(*file_id));
244 DEBUG(3,("kernel oplock break request for file dev = %x, inode = %.0f, file_id = %lu\n",
245 (unsigned int)*dev, (double)*inode, *file_id));
250 /****************************************************************************
251 See if a oplock message is waiting.
252 ****************************************************************************/
254 static BOOL linux_oplock_msg_waiting(fd_set *fds)
256 return signals_received != 0;
259 /****************************************************************************
260 See if the kernel supports oplocks.
261 ****************************************************************************/
263 static BOOL linux_oplocks_available(void)
266 fd = open("/dev/null", O_RDONLY);
268 return False; /* uggh! */
269 ret = fcntl(fd, F_GETLEASE, 0);
271 return ret == F_UNLCK;
274 /****************************************************************************
275 Setup kernel oplocks.
276 ****************************************************************************/
278 struct kernel_oplocks *linux_init_kernel_oplocks(void)
280 static struct kernel_oplocks koplocks;
281 struct sigaction act;
283 if (!linux_oplocks_available()) {
284 DEBUG(3,("Linux kernel oplocks not available\n"));
290 act.sa_handler = NULL;
291 act.sa_sigaction = signal_handler;
292 act.sa_flags = SA_SIGINFO;
293 sigemptyset( &act.sa_mask );
294 if (sigaction(RT_SIGNAL_LEASE, &act, NULL) != 0) {
295 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler\n"));
299 koplocks.receive_message = linux_oplock_receive_message;
300 koplocks.set_oplock = linux_set_kernel_oplock;
301 koplocks.release_oplock = linux_release_kernel_oplock;
302 koplocks.parse_message = linux_kernel_oplock_parse;
303 koplocks.msg_waiting = linux_oplock_msg_waiting;
304 koplocks.notification_fd = -1;
306 /* the signal can start off blocked due to a bug in bash */
307 BlockSignals(False, RT_SIGNAL_LEASE);
309 DEBUG(3,("Linux kernel oplocks enabled\n"));
314 void oplock_linux_dummy(void) {}
315 #endif /* HAVE_KERNEL_OPLOCKS_LINUX */