/* Unix SMB/Netbios implementation. Version 3.0 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 extern int DEBUGLEVEL; 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) { SMB_DEV_T dev; SMB_INO_T inode; SMB_STRUCT_STAT sbuf; BOOL ret = True; if (signals_received == signals_processed) return False; if (sys_fstat((int)fd_pending,&sbuf) == -1) { DEBUG(0,("Invalid file descriptor %d in kernel oplock break!\n", (int)fd_pending)); ret = False; goto out; } dev = sbuf.st_dev; inode = sbuf.st_ino; DEBUG(3,("receive_local_message: kernel oplock break request received for \ dev = %x, inode = %.0f\n", (unsigned int)dev, (double)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 *)&dev, sizeof(dev)); memcpy(buffer + KERNEL_OPLOCK_BREAK_INODE_OFFSET, (char *)&inode, sizeof(inode)); 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\n", fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode)); 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 has kernel \ oplock state of %x.\n", fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode, 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. Error was %s\n", fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode, 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) { /* 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)); DEBUG(3,("kernel oplock break request for file dev = %x, inode = %.0f\n", (unsigned int)*dev, (double)*inode)); 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 */