source/smbd/oplock_linux.c

   1 #define OLD_NTDOMAIN 1
   2
   3 /*
   4    Unix SMB/Netbios implementation.
   5    Version 3.0
   6    kernel oplock processing for Linux
   7    Copyright (C) Andrew Tridgell 2000
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "includes.h"
  25
  26 #if HAVE_KERNEL_OPLOCKS_LINUX
  27
  28 extern int DEBUGLEVEL;
  29
  30 static VOLATILE SIG_ATOMIC_T signals_received;
  31 static VOLATILE SIG_ATOMIC_T signals_processed;
  32 static VOLATILE SIG_ATOMIC_T fd_pending; /* the fd of the current pending signal */
  33
  34 #ifndef F_SETLEASE
  35 #define F_SETLEASE      1024
  36 #endif
  37
  38 #ifndef F_GETLEASE
  39 #define F_GETLEASE      1025
  40 #endif
  41
  42 #ifndef CAP_LEASE
  43 #define CAP_LEASE 28
  44 #endif
  45
  46 #ifndef RT_SIGNAL_LEASE
  47 #define RT_SIGNAL_LEASE 33
  48 #endif
  49
  50 #ifndef F_SETSIG
  51 #define F_SETSIG 10
  52 #endif
  53
  54 /****************************************************************************
  55 handle a LEASE signal, incrementing the signals_received and blocking the signal
  56 ****************************************************************************/
  57 static void signal_handler(int signal, siginfo_t *info, void *unused)
  58 {
  59         BlockSignals(True, signal);
  60         fd_pending = (SIG_ATOMIC_T)info->si_fd;
  61         signals_received++;
  62         sys_select_signal();
  63 }
  64
  65 /****************************************************************************
  66 try to gain a linux capability
  67 ****************************************************************************/static void set_capability(unsigned capability)
  68 {
  69 #ifndef _LINUX_CAPABILITY_VERSION
  70 #define _LINUX_CAPABILITY_VERSION 0x19980330
  71 #endif
  72         /* these can be removed when they are in glibc headers */
  73         struct  {
  74                 uint32 version;
  75                 int pid;
  76         } header;
  77         struct {
  78                 uint32 effective;
  79                 uint32 permitted;
  80                 uint32 inheritable;
  81         } data;
  82
  83         header.version = _LINUX_CAPABILITY_VERSION;
  84         header.pid = 0;
  85
  86         if (capget(&header, &data) == -1) {
  87                 DEBUG(3,("Unable to get kernel capabilities (%s)\n", strerror(errno)));
  88                 return;
  89         }
  90
  91         data.effective |= (1<<capability);
  92
  93         if (capset(&header, &data) == -1) {
  94                 DEBUG(3,("Unable to set %d capability (%s)\n",
  95                          capability, strerror(errno)));
  96         }
  97 }
  98
  99
 100 /****************************************************************************
 101 call SETLEASE. If we get EACCES then we try setting up the right capability and
 102 try again
 103 ****************************************************************************/
 104 static int linux_setlease(int fd, int leasetype)
 105 {
 106         int ret;
 107
 108         if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) {
 109                 DEBUG(3,("Failed to set signal handler for kernel lease\n"));
 110                 return -1;
 111         }
 112
 113         ret = fcntl(fd, F_SETLEASE, leasetype);
 114         if (ret == -1 && errno == EACCES) {
 115                 set_capability(CAP_LEASE);
 116                 ret = fcntl(fd, F_SETLEASE, leasetype);
 117         }
 118
 119         return ret;
 120 }
 121
 122
 123 /****************************************************************************
 124  * Deal with the Linux kernel <--> smbd
 125  * oplock break protocol.
 126 ****************************************************************************/
 127 static BOOL linux_oplock_receive_message(fd_set *fds, char *buffer, int buffer_len)
 128 {
 129         SMB_DEV_T dev;
 130         SMB_INO_T inode;
 131         SMB_STRUCT_STAT sbuf;
 132         BOOL ret;
 133
 134         if (signals_received == signals_processed) return False;
 135
 136         if (sys_fstat((int)fd_pending,&sbuf) == -1) {
 137                 DEBUG(0,("Invalid file descriptor %d in kernel oplock break!\n", (int)fd_pending));
 138                 ret = False;
 139                 goto out;
 140         }
 141
 142         dev = sbuf.st_dev;
 143         inode = sbuf.st_ino;
 144
 145         DEBUG(3,("receive_local_message: kernel oplock break request received for \
 146 dev = %x, inode = %.0f\n", (unsigned int)dev, (double)inode ));
 147
 148         /*
 149          * Create a kernel oplock break message.
 150          */
 151
 152         /* Setup the message header */
 153         SIVAL(buffer,OPBRK_CMD_LEN_OFFSET,KERNEL_OPLOCK_BREAK_MSG_LEN);
 154         SSVAL(buffer,OPBRK_CMD_PORT_OFFSET,0);
 155
 156         buffer += OPBRK_CMD_HEADER_LEN;
 157
 158         SSVAL(buffer,OPBRK_MESSAGE_CMD_OFFSET,KERNEL_OPLOCK_BREAK_CMD);
 159
 160         memcpy(buffer + KERNEL_OPLOCK_BREAK_DEV_OFFSET, (char *)&dev, sizeof(dev));
 161         memcpy(buffer + KERNEL_OPLOCK_BREAK_INODE_OFFSET, (char *)&inode, sizeof(inode));
 162
 163  out:
 164         /* now we can receive more signals */
 165         fd_pending = (SIG_ATOMIC_T)-1;
 166         signals_processed++;
 167         BlockSignals(False, RT_SIGNAL_LEASE);
 168
 169         return True;
 170 }
 171
 172
 173 /****************************************************************************
 174  Attempt to set an kernel oplock on a file.
 175 ****************************************************************************/
 176 static BOOL linux_set_kernel_oplock(files_struct *fsp, int oplock_type)
 177 {
 178         if (linux_setlease(fsp->fd, F_WRLCK) == -1) {
 179                 DEBUG(3,("set_file_oplock: Refused oplock on file %s, fd = %d, dev = %x, \
 180 inode = %.0f. (%s)\n",
 181                          fsp->fsp_name, fsp->fd,
 182                          (unsigned int)fsp->dev, (double)fsp->inode, strerror(errno)));
 183                 return False;
 184         }
 185
 186         DEBUG(3,("set_file_oplock: got kernel oplock on file %s, dev = %x, inode = %.0f\n",
 187                   fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode));
 188
 189         return True;
 190 }
 191
 192
 193 /****************************************************************************
 194  Release a kernel oplock on a file.
 195 ****************************************************************************/
 196 static void linux_release_kernel_oplock(files_struct *fsp)
 197 {
 198         if (DEBUGLVL(10)) {
 199                 /*
 200                  * Check and print out the current kernel
 201                  * oplock state of this file.
 202                  */
 203                 int state = fcntl(fsp->fd, F_GETLEASE, 0);
 204                 dbgtext("release_kernel_oplock: file %s, dev = %x, inode = %.0f has kernel \
 205 oplock state of %x.\n", fsp->fsp_name, (unsigned int)fsp->dev,
 206                         (double)fsp->inode, state );
 207         }
 208
 209         /*
 210          * Remove the kernel oplock on this file.
 211          */
 212         if (linux_setlease(fsp->fd, F_UNLCK) == -1) {
 213                 if (DEBUGLVL(0)) {
 214                         dbgtext("release_kernel_oplock: Error when removing kernel oplock on file " );
 215                         dbgtext("%s, dev = %x, inode = %.0f. Error was %s\n",
 216                                 fsp->fsp_name, (unsigned int)fsp->dev,
 217                                 (double)fsp->inode, strerror(errno) );
 218                 }
 219         }
 220 }
 221
 222
 223 /****************************************************************************
 224 parse a kernel oplock message
 225 ****************************************************************************/
 226 static BOOL linux_kernel_oplock_parse(char *msg_start, int msg_len, SMB_INO_T *inode, SMB_DEV_T *dev)
 227 {
 228         /* Ensure that the msg length is correct. */
 229         if (msg_len != KERNEL_OPLOCK_BREAK_MSG_LEN) {
 230                 DEBUG(0,("incorrect length for KERNEL_OPLOCK_BREAK_CMD (was %d, should be %d).\n",
 231                          msg_len, KERNEL_OPLOCK_BREAK_MSG_LEN));
 232                 return False;
 233         }
 234
 235         memcpy((char *)inode, msg_start+KERNEL_OPLOCK_BREAK_INODE_OFFSET, sizeof(*inode));
 236         memcpy((char *)dev, msg_start+KERNEL_OPLOCK_BREAK_DEV_OFFSET, sizeof(*dev));
 237
 238         DEBUG(3,("kernel oplock break request for file dev = %x, inode = %.0f\n",
 239                  (unsigned int)*dev, (double)*inode));
 240
 241         return True;
 242 }
 243
 244
 245 /****************************************************************************
 246 see if a oplock message is waiting
 247 ****************************************************************************/
 248 static BOOL linux_oplock_msg_waiting(fd_set *fds)
 249 {
 250         return signals_processed != signals_received;
 251 }
 252
 253 /****************************************************************************
 254 see if the kernel supports oplocks
 255 ****************************************************************************/
 256 static BOOL linux_oplocks_available(void)
 257 {
 258         int fd, ret;
 259         fd = open("/dev/null", O_RDONLY);
 260         if (fd == -1) return False; /* uggh! */
 261         ret = fcntl(fd, F_GETLEASE, 0);
 262         close(fd);
 263         return ret == F_UNLCK;
 264 }
 265
 266
 267 /****************************************************************************
 268 setup kernel oplocks
 269 ****************************************************************************/
 270 struct kernel_oplocks *linux_init_kernel_oplocks(void)
 271 {
 272         static struct kernel_oplocks koplocks;
 273         struct sigaction act;
 274
 275         if (!linux_oplocks_available()) {
 276                 DEBUG(3,("Linux kernel oplocks not available\n"));
 277                 return NULL;
 278         }
 279
 280         act.sa_handler = NULL;
 281         act.sa_sigaction = signal_handler;
 282         act.sa_flags = SA_SIGINFO;
 283         if (sigaction(RT_SIGNAL_LEASE, &act, NULL) != 0) {
 284                 DEBUG(0,("Failed to setup RT_SIGNAL_LEASE handler\n"));
 285                 return NULL;
 286         }
 287
 288         koplocks.receive_message = linux_oplock_receive_message;
 289         koplocks.set_oplock = linux_set_kernel_oplock;
 290         koplocks.release_oplock = linux_release_kernel_oplock;
 291         koplocks.parse_message = linux_kernel_oplock_parse;
 292         koplocks.msg_waiting = linux_oplock_msg_waiting;
 293         koplocks.notification_fd = -1;
 294
 295         DEBUG(3,("Linux kernel oplocks enabled\n"));
 296
 297         return &koplocks;
 298 }
 299
 300
 301
 302 #else
 303  void oplock_linux_dummy(void) {}
 304 #endif /* HAVE_KERNEL_OPLOCKS_LINUX */
 305
 306 #undef OLD_NTDOMAIN
 307