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/*
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 */
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