1 files changed, 300 insertions, 0 deletions
diff --git a/source3/smbd/oplock_linux.c b/source3/smbd/oplock_linux.c
new file mode 100644
index 0000000000..d946578380
--- /dev/null
+++ b/source3/smbd/oplock_linux.c
@@ -0,0 +1,300 @@
+/* 
+   Unix SMB/CIFS implementation.
+   kernel oplock processing for Linux
+   Copyright (C) Andrew Tridgell 2000
+   
+   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.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+
+#if HAVE_KERNEL_OPLOCKS_LINUX
+
+static VOLATILE sig_atomic_t signals_received;
+static VOLATILE sig_atomic_t signals_processed;
+static VOLATILE sig_atomic_t fd_pending; /* the fd of the current pending signal */
+
+#ifndef F_SETLEASE
+#define F_SETLEASE	1024
+#endif
+
+#ifndef F_GETLEASE
+#define F_GETLEASE	1025
+#endif
+
+#ifndef CAP_LEASE
+#define CAP_LEASE 28
+#endif
+
+#ifndef RT_SIGNAL_LEASE
+#define RT_SIGNAL_LEASE 33
+#endif
+
+#ifndef F_SETSIG
+#define F_SETSIG 10
+#endif
+
+/****************************************************************************
+ Handle a LEASE signal, incrementing the signals_received and blocking the signal.
+****************************************************************************/
+
+static void signal_handler(int sig, siginfo_t *info, void *unused)
+{
+	BlockSignals(True, sig);
+	fd_pending = (sig_atomic_t)info->si_fd;
+	signals_received++;
+	sys_select_signal();
+}
+
+/****************************************************************************
+ Try to gain a linux capability.
+****************************************************************************/
+
+static void set_capability(unsigned capability)
+{
+#ifndef _LINUX_CAPABILITY_VERSION
+#define _LINUX_CAPABILITY_VERSION 0x19980330
+#endif
+	/* these can be removed when they are in glibc headers */
+	struct  {
+		uint32 version;
+		int pid;
+	} header;
+	struct {
+		uint32 effective;
+		uint32 permitted;
+		uint32 inheritable;
+	} data;
+
+	header.version = _LINUX_CAPABILITY_VERSION;
+	header.pid = 0;
+
+	if (capget(&header, &data) == -1) {
+		DEBUG(3,("Unable to get kernel capabilities (%s)\n", strerror(errno)));
+		return;
+	}
+
+	data.effective |= (1<<capability);
+
+	if (capset(&header, &data) == -1) {
+		DEBUG(3,("Unable to set %d capability (%s)\n", 
+			 capability, strerror(errno)));
+	}
+}
+
+/****************************************************************************
+ Call SETLEASE. If we get EACCES then we try setting up the right capability and
+ try again
+****************************************************************************/
+
+static int linux_setlease(int fd, int leasetype)
+{
+	int ret;
+
+	if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
+		DEBUG(3,("Failed to set signal handler for kernel lease\n"));
+		return -1;
+	}
+
+	ret = fcntl(fd, F_SETLEASE, leasetype);
+	if (ret == -1 && errno == EACCES) {
+		set_capability(CAP_LEASE);
+		ret = fcntl(fd, F_SETLEASE, leasetype);
+	}
+
+	return ret;
+}
+
+/****************************************************************************
+ * Deal with the Linux kernel <--> smbd
+ * oplock break protocol.
+****************************************************************************/
+
+static BOOL linux_oplock_receive_message(fd_set *fds, char *buffer, int buffer_len)
+{
+	BOOL ret = True;
+	struct files_struct *fsp;
+
+	if (signals_received == signals_processed)
+		return False;
+
+	if ((fsp = file_find_fd(fd_pending)) == NULL) {
+		DEBUG(0,("Invalid file descriptor %d in kernel oplock break!\n", (int)fd_pending));
+		ret = False;
+		goto out;
+	}
+
+	DEBUG(3,("receive_local_message: kernel oplock break request received for \
+dev = %x, inode = %.0f\n", (unsigned int)fsp->dev, (double)fsp->inode ));
+     
+	/*
+	 * Create a kernel oplock break message.
+	 */
+     
+	/* Setup the message header */
+	SIVAL(buffer,OPBRK_CMD_LEN_OFFSET,KERNEL_OPLOCK_BREAK_MSG_LEN);
+	SSVAL(buffer,OPBRK_CMD_PORT_OFFSET,0);
+     
+	buffer += OPBRK_CMD_HEADER_LEN;
+     
+	SSVAL(buffer,OPBRK_MESSAGE_CMD_OFFSET,KERNEL_OPLOCK_BREAK_CMD);
+     
+	memcpy(buffer + KERNEL_OPLOCK_BREAK_DEV_OFFSET, (char *)&fsp->dev, sizeof(fsp->dev));
+	memcpy(buffer + KERNEL_OPLOCK_BREAK_INODE_OFFSET, (char *)&fsp->inode, sizeof(fsp->inode));	
+	memcpy(buffer + KERNEL_OPLOCK_BREAK_FILEID_OFFSET, (char *)&fsp->file_id, sizeof(fsp->file_id));	
+
+ out:
+	/* now we can receive more signals */
+	fd_pending = (sig_atomic_t)-1;
+	signals_processed++;
+	BlockSignals(False, RT_SIGNAL_LEASE);
+     
+	return ret;
+}
+
+/****************************************************************************
+ Attempt to set an kernel oplock on a file.
+****************************************************************************/
+
+static BOOL linux_set_kernel_oplock(files_struct *fsp, int oplock_type)
+{
+	if (linux_setlease(fsp->fd, F_WRLCK) == -1) {
+		DEBUG(3,("set_file_oplock: Refused oplock on file %s, fd = %d, dev = %x, \
+inode = %.0f. (%s)\n",
+			 fsp->fsp_name, fsp->fd, 
+			 (unsigned int)fsp->dev, (double)fsp->inode, strerror(errno)));
+		return False;
+	}
+	
+	DEBUG(3,("set_file_oplock: got kernel oplock on file %s, dev = %x, inode = %.0f, file_id = %lu\n",
+		  fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode, fsp->file_id));
+
+	return True;
+}
+
+/****************************************************************************
+ Release a kernel oplock on a file.
+****************************************************************************/
+
+static void linux_release_kernel_oplock(files_struct *fsp)
+{
+	if (DEBUGLVL(10)) {
+		/*
+		 * Check and print out the current kernel
+		 * oplock state of this file.
+		 */
+		int state = fcntl(fsp->fd, F_GETLEASE, 0);
+		dbgtext("release_kernel_oplock: file %s, dev = %x, inode = %.0f file_id = %lu has kernel \
+oplock state of %x.\n", fsp->fsp_name, (unsigned int)fsp->dev,
+                        (double)fsp->inode, fsp->file_id, state );
+	}
+
+	/*
+	 * Remove the kernel oplock on this file.
+	 */
+	if (linux_setlease(fsp->fd, F_UNLCK) == -1) {
+		if (DEBUGLVL(0)) {
+			dbgtext("release_kernel_oplock: Error when removing kernel oplock on file " );
+			dbgtext("%s, dev = %x, inode = %.0f, file_id = %lu. Error was %s\n",
+				fsp->fsp_name, (unsigned int)fsp->dev, 
+				(double)fsp->inode, fsp->file_id, strerror(errno) );
+		}
+	}
+}
+
+/****************************************************************************
+ Parse a kernel oplock message.
+****************************************************************************/
+
+static BOOL linux_kernel_oplock_parse(char *msg_start, int msg_len, SMB_INO_T *inode,
+		SMB_DEV_T *dev, unsigned long *file_id)
+{
+	/* Ensure that the msg length is correct. */
+	if (msg_len != KERNEL_OPLOCK_BREAK_MSG_LEN) {
+		DEBUG(0,("incorrect length for KERNEL_OPLOCK_BREAK_CMD (was %d, should be %d).\n", 
+			 msg_len, KERNEL_OPLOCK_BREAK_MSG_LEN));
+		return False;
+	}
+
+	memcpy((char *)inode, msg_start+KERNEL_OPLOCK_BREAK_INODE_OFFSET, sizeof(*inode));
+	memcpy((char *)dev, msg_start+KERNEL_OPLOCK_BREAK_DEV_OFFSET, sizeof(*dev));
+	memcpy((char *)file_id, msg_start+KERNEL_OPLOCK_BREAK_FILEID_OFFSET, sizeof(*file_id));
+
+	DEBUG(3,("kernel oplock break request for file dev = %x, inode = %.0f, file_id = %lu\n", 
+		(unsigned int)*dev, (double)*inode, *file_id));
+
+	return True;
+}
+
+/****************************************************************************
+ See if a oplock message is waiting.
+****************************************************************************/
+
+static BOOL linux_oplock_msg_waiting(fd_set *fds)
+{
+	return signals_processed != signals_received;
+}
+
+/****************************************************************************
+ See if the kernel supports oplocks.
+****************************************************************************/
+
+static BOOL linux_oplocks_available(void)
+{
+	int fd, ret;
+	fd = open("/dev/null", O_RDONLY);
+	if (fd == -1)
+		return False; /* uggh! */
+	ret = fcntl(fd, F_GETLEASE, 0);
+	close(fd);
+	return ret == F_UNLCK;
+}
+
+/****************************************************************************
+ Setup kernel oplocks.
+****************************************************************************/
+
+struct kernel_oplocks *linux_init_kernel_oplocks(void) 
+{
+	static struct kernel_oplocks koplocks;
+        struct sigaction act;
+
+	if (!linux_oplocks_available()) {
+		DEBUG(3,("Linux kernel oplocks not available\n"));
+		return NULL;
+	}
+
+	act.sa_handler = NULL;
+	act.sa_sigaction = signal_handler;
+	act.sa_flags = SA_SIGINFO;
+	if (sigaction(RT_SIGNAL_LEASE, &act, NULL) != 0) {
+		DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler\n"));
+		return NULL;
+	}
+
+	koplocks.receive_message = linux_oplock_receive_message;
+	koplocks.set_oplock = linux_set_kernel_oplock;
+	koplocks.release_oplock = linux_release_kernel_oplock;
+	koplocks.parse_message = linux_kernel_oplock_parse;
+	koplocks.msg_waiting = linux_oplock_msg_waiting;
+	koplocks.notification_fd = -1;
+
+	DEBUG(3,("Linux kernel oplocks enabled\n"));
+
+	return &koplocks;
+}
+#else
+ void oplock_linux_dummy(void) {}
+#endif /* HAVE_KERNEL_OPLOCKS_LINUX */