--- /dev/null
+/*
+ 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
+
+/* these can be removed when they are in glibc headers */
+struct cap_user_header {
+ uint32 version;
+ int pid;
+} header;
+struct cap_user_data {
+ uint32 effective;
+ uint32 permitted;
+ uint32 inheritable;
+} data;
+
+extern int capget(struct cap_user_header * hdrp,
+ struct cap_user_data * datap);
+extern int capset(struct cap_user_header * hdrp,
+ const struct cap_user_data * datap);
+
+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);
+}
+
+/****************************************************************************
+ Try to gain a linux capability.
+****************************************************************************/
+
+static void set_capability(unsigned capability)
+{
+#ifndef _LINUX_CAPABILITY_VERSION
+#define _LINUX_CAPABILITY_VERSION 0x19980330
+#endif
+ 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 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 (linux_setlease(fsp->fh->fd, F_WRLCK) == -1) {
+ DEBUG(3,("linux_set_kernel_oplock: Refused oplock on file %s, fd = %d, dev = %x, \
+inode = %.0f. (%s)\n",
+ fsp->fsp_name, fsp->fh->fd,
+ (unsigned int)fsp->dev, (double)fsp->inode, strerror(errno)));
+ return False;
+ }
+
+ DEBUG(3,("linux_set_kernel_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->fh->fd, F_GETLEASE, 0);
+ dbgtext("linux_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->fh->fd, F_UNLCK) == -1) {
+ if (DEBUGLVL(0)) {
+ dbgtext("linux_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) );
+ }
+ }
+}
+
+/****************************************************************************
+ 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 */
projects / samba / blobdiff