1 files changed, 249 insertions, 0 deletions
diff --git a/source3/smbd/oplock_linux.c b/source3/smbd/oplock_linux.c
new file mode 100644
index 0000000000..08df228f8f
--- /dev/null
+++ b/source3/smbd/oplock_linux.c
@@ -0,0 +1,249 @@
+/* 
+   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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+#define DBGC_CLASS DBGC_LOCKING
+#include "includes.h"
+
+#if HAVE_KERNEL_OPLOCKS_LINUX
+
+static SIG_ATOMIC_T signals_received;
+#define FD_PENDING_SIZE 100
+static SIG_ATOMIC_T fd_pending_array[FD_PENDING_SIZE];
+
+#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 (SIGRTMIN+1)
+#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)
+{
+	if (signals_received < FD_PENDING_SIZE - 1) {
+		fd_pending_array[signals_received] = (SIG_ATOMIC_T)info->si_fd;
+		signals_received++;
+	} /* Else signal is lost. */
+	sys_select_signal(RT_SIGNAL_LEASE);
+}
+
+/*
+ * public function to get linux lease capability. Needed by some VFS modules (eg. gpfs.c)
+ */
+void linux_set_lease_capability(void)
+{
+	set_effective_capability(LEASE_CAPABILITY);
+}
+
+/* 
+ * Call to set the kernel lease signal handler
+ */
+int linux_set_lease_sighandler(int fd)
+{
+        if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
+                DEBUG(3,("Failed to set signal handler for kernel lease\n"));
+                return -1;
+        }
+
+	return 0;
+}
+
+/****************************************************************************
+ Call SETLEASE. If we get EACCES then we try setting up the right capability and
+ try again.
+ Use the SMB_VFS_LINUX_SETLEASE instead of this call directly.
+****************************************************************************/
+
+int linux_setlease(int fd, int leasetype)
+{
+	int ret;
+
+	ret = fcntl(fd, F_SETLEASE, leasetype);
+	if (ret == -1 && errno == EACCES) {
+		set_effective_capability(LEASE_CAPABILITY);
+		ret = fcntl(fd, F_SETLEASE, leasetype);
+	}
+
+	return ret;
+}
+
+/****************************************************************************
+ * Deal with the Linux kernel <--> smbd
+ * oplock break protocol.
+****************************************************************************/
+
+static files_struct *linux_oplock_receive_message(fd_set *fds)
+{
+	int fd;
+	files_struct *fsp;
+
+	BlockSignals(True, RT_SIGNAL_LEASE);
+	fd = fd_pending_array[0];
+	fsp = file_find_fd(fd);
+	fd_pending_array[0] = (SIG_ATOMIC_T)-1;
+	if (signals_received > 1)
+                memmove(CONST_DISCARD(void *, &fd_pending_array[0]),
+                        CONST_DISCARD(void *, &fd_pending_array[1]),
+			sizeof(SIG_ATOMIC_T)*(signals_received-1));
+	signals_received--;
+	/* now we can receive more signals */
+	BlockSignals(False, RT_SIGNAL_LEASE);
+
+	return fsp;
+}
+
+/****************************************************************************
+ Attempt to set an kernel oplock on a file.
+****************************************************************************/
+
+static bool linux_set_kernel_oplock(files_struct *fsp, int oplock_type)
+{
+	if ( SMB_VFS_LINUX_SETLEASE(fsp, F_WRLCK) == -1) {
+		DEBUG(3,("linux_set_kernel_oplock: Refused oplock on file %s, "
+			 "fd = %d, file_id = %s. (%s)\n",
+			 fsp->fsp_name, fsp->fh->fd, 
+			 file_id_string_tos(&fsp->file_id),
+			 strerror(errno)));
+		return False;
+	}
+	
+	DEBUG(3,("linux_set_kernel_oplock: got kernel oplock on file %s, "
+		 "file_id = %s gen_id = %lu\n",
+		 fsp->fsp_name, file_id_string_tos(&fsp->file_id),
+		 fsp->fh->gen_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->fh->fd, F_GETLEASE, 0);
+		dbgtext("linux_release_kernel_oplock: file %s, file_id = %s "
+			"gen_id = %lu has kernel oplock state "
+			"of %x.\n", fsp->fsp_name, file_id_string_tos(&fsp->file_id),
+			fsp->fh->gen_id, state );
+	}
+
+	/*
+	 * Remove the kernel oplock on this file.
+	 */
+	if ( SMB_VFS_LINUX_SETLEASE(fsp, F_UNLCK) == -1) {
+		if (DEBUGLVL(0)) {
+			dbgtext("linux_release_kernel_oplock: Error when "
+				"removing kernel oplock on file " );
+			dbgtext("%s, file_id = %s, gen_id = %lu. "
+				"Error was %s\n", fsp->fsp_name,
+				file_id_string_tos(&fsp->file_id),
+				fsp->fh->gen_id, strerror(errno) );
+		}
+	}
+}
+
+/****************************************************************************
+ See if a oplock message is waiting.
+****************************************************************************/
+
+static bool linux_oplock_msg_waiting(fd_set *fds)
+{
+	return signals_received != 0;
+}
+
+/****************************************************************************
+ 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;
+	}
+
+	ZERO_STRUCT(act);
+
+	act.sa_handler = NULL;
+	act.sa_sigaction = signal_handler;
+	act.sa_flags = SA_SIGINFO;
+	sigemptyset( &act.sa_mask );
+	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.msg_waiting = linux_oplock_msg_waiting;
+	koplocks.notification_fd = -1;
+
+	/* the signal can start off blocked due to a bug in bash */
+	BlockSignals(False, RT_SIGNAL_LEASE);
+
+	DEBUG(3,("Linux kernel oplocks enabled\n"));
+
+	return &koplocks;
+}
+#else
+ void oplock_linux_dummy(void);
+
+ void oplock_linux_dummy(void) {}
+#endif /* HAVE_KERNEL_OPLOCKS_LINUX */