1 files changed, 243 insertions, 0 deletions
diff --git a/source3/smbd/oplock_linux.c b/source3/smbd/oplock_linux.c
new file mode 100644
index 0000000..3ed2001
--- /dev/null
+++ b/source3/smbd/oplock_linux.c
@@ -0,0 +1,243 @@
+/* 
+   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"
+#include "system/filesys.h"
+#include "smbd/smbd.h"
+#include "smbd/globals.h"
+
+#ifdef HAVE_KERNEL_OPLOCKS_LINUX
+
+#ifndef RT_SIGNAL_LEASE
+#define RT_SIGNAL_LEASE (SIGRTMIN+1)
+#endif
+
+/* 
+ * Call to set the kernel lease signal handler
+ */
+int linux_set_lease_sighandler(int fd)
+{
+        if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
+                DBG_NOTICE("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;
+	int saved_errno = 0;
+
+	/*
+	 * Ensure the lease owner is root to allow
+	 * correct delivery of lease-break signals.
+	 */
+
+	become_root();
+
+	/* First set the signal handler. */
+	if (linux_set_lease_sighandler(fd) == -1) {
+		saved_errno = errno;
+		ret = -1;
+		goto out;
+	}
+	ret = fcntl(fd, F_SETLEASE, leasetype);
+	if (ret == -1) {
+		saved_errno = errno;
+	}
+
+  out:
+
+	unbecome_root();
+
+	if (ret == -1) {
+		errno = saved_errno;
+	}
+	return ret;
+}
+
+/****************************************************************************
+ * Deal with the Linux kernel <--> smbd
+ * oplock break protocol.
+****************************************************************************/
+
+static void linux_oplock_signal_handler(struct tevent_context *ev_ctx,
+					struct tevent_signal *se,
+					int signum, int count,
+					void *_info, void *private_data)
+{
+	struct kernel_oplocks *ctx =
+		talloc_get_type_abort(private_data,
+		struct kernel_oplocks);
+	struct smbd_server_connection *sconn =
+		talloc_get_type_abort(ctx->private_data,
+		struct smbd_server_connection);
+	siginfo_t *info = (siginfo_t *)_info;
+	int fd = info->si_fd;
+	files_struct *fsp;
+
+	fsp = file_find_fd(sconn, fd);
+	if (fsp == NULL) {
+		DBG_ERR("linux_oplock_signal_handler: failed to find fsp for file fd=%d (file was closed ?)\n", fd );
+		return;
+	}
+	break_kernel_oplock(sconn->msg_ctx, fsp);
+}
+
+/****************************************************************************
+ Attempt to set an kernel oplock on a file.
+****************************************************************************/
+
+static bool linux_set_kernel_oplock(struct kernel_oplocks *ctx,
+				    files_struct *fsp, int oplock_type)
+{
+	struct file_id_buf idbuf;
+
+	if ( SMB_VFS_LINUX_SETLEASE(fsp, F_WRLCK) == -1) {
+		DBG_NOTICE("Refused oplock on file %s, "
+			   "fd = %d, file_id = %s. (%s)\n",
+			   fsp_str_dbg(fsp),
+			   fsp_get_io_fd(fsp),
+			   file_id_str_buf(fsp->file_id, &idbuf),
+			   strerror(errno));
+		return False;
+	}
+	
+	DBG_NOTICE("got kernel oplock on file %s, "
+		   "file_id = %s gen_id = %"PRIu64"\n",
+		   fsp_str_dbg(fsp),
+		   file_id_str_buf(fsp->file_id, &idbuf),
+		   fh_get_gen_id(fsp->fh));
+
+	return True;
+}
+
+/****************************************************************************
+ Release a kernel oplock on a file.
+****************************************************************************/
+
+static void linux_release_kernel_oplock(struct kernel_oplocks *ctx,
+					files_struct *fsp, int oplock_type)
+{
+	struct file_id_buf idbuf;
+
+	if (DEBUGLVL(DBGLVL_DEBUG)) {
+		/*
+		 * Check and print out the current kernel
+		 * oplock state of this file.
+		 */
+		int state = fcntl(fsp_get_io_fd(fsp), F_GETLEASE, 0);
+		dbgtext("linux_release_kernel_oplock: file %s, file_id = %s "
+			"gen_id = %"PRIu64" has kernel oplock state "
+			"of %x.\n",
+			fsp_str_dbg(fsp),
+		        file_id_str_buf(fsp->file_id, &idbuf),
+			fh_get_gen_id(fsp->fh),
+			state);
+	}
+
+	/*
+	 * Remove the kernel oplock on this file.
+	 */
+	if ( SMB_VFS_LINUX_SETLEASE(fsp, F_UNLCK) == -1) {
+		if (DEBUGLVL(DBGLVL_ERR)) {
+			dbgtext("linux_release_kernel_oplock: Error when "
+				"removing kernel oplock on file " );
+			dbgtext("%s, file_id = %s, gen_id = %"PRIu64". "
+				"Error was %s\n",
+				fsp_str_dbg(fsp),
+				file_id_str_buf(fsp->file_id, &idbuf),
+				fh_get_gen_id(fsp->fh),
+				strerror(errno));
+		}
+	}
+}
+
+/****************************************************************************
+ 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.
+****************************************************************************/
+
+static const struct kernel_oplocks_ops linux_koplocks = {
+	.set_oplock			= linux_set_kernel_oplock,
+	.release_oplock			= linux_release_kernel_oplock,
+};
+
+struct kernel_oplocks *linux_init_kernel_oplocks(struct smbd_server_connection *sconn)
+{
+	struct kernel_oplocks *ctx;
+	struct tevent_signal *se;
+
+	if (!linux_oplocks_available()) {
+		DBG_NOTICE("Linux kernel oplocks not available\n");
+		return NULL;
+	}
+
+	ctx = talloc_zero(sconn, struct kernel_oplocks);
+	if (!ctx) {
+		DBG_ERR("Linux Kernel oplocks talloc_Zero failed\n");
+		return NULL;
+	}
+
+	ctx->ops = &linux_koplocks;
+	ctx->private_data = sconn;
+
+	se = tevent_add_signal(sconn->ev_ctx,
+			       ctx,
+			       RT_SIGNAL_LEASE, SA_SIGINFO,
+			       linux_oplock_signal_handler,
+			       ctx);
+	if (!se) {
+		DBG_ERR("Failed to setup RT_SIGNAL_LEASE handler\n");
+		TALLOC_FREE(ctx);
+		return NULL;
+	}
+
+	DBG_NOTICE("Linux kernel oplocks enabled\n");
+
+	return ctx;
+}
+#else
+ void oplock_linux_dummy(void);
+
+ void oplock_linux_dummy(void) {}
+#endif /* HAVE_KERNEL_OPLOCKS_LINUX */