source/smbd/oplock_irix.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    IRIX kernel oplock processing
   4    Copyright (C) Andrew Tridgell 1992-1998
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #define DBGC_CLASS DBGC_LOCKING
  21 #include "includes.h"
  22
  23 #if HAVE_KERNEL_OPLOCKS_IRIX
  24
  25 static int oplock_pipe_write = -1;
  26 static int oplock_pipe_read = -1;
  27
  28 /****************************************************************************
  29  Test to see if IRIX kernel oplocks work.
  30 ****************************************************************************/
  31
  32 static bool irix_oplocks_available(void)
  33 {
  34         int fd;
  35         int pfd[2];
  36         TALLOC_CTX *ctx = talloc_stackframe();
  37         char *tmpname = NULL;
  38
  39         set_effective_capability(KERNEL_OPLOCK_CAPABILITY);
  40
  41         tmpname = talloc_asprintf(ctx,
  42                                 "%s/koplock.%d",
  43                                 lp_lockdir(),
  44                                 (int)sys_getpid());
  45         if (!tmpname) {
  46                 TALLOC_FREE(ctx);
  47                 return False;
  48         }
  49
  50         if(pipe(pfd) != 0) {
  51                 DEBUG(0,("check_kernel_oplocks: Unable to create pipe. Error "
  52                          "was %s\n",
  53                          strerror(errno) ));
  54                 TALLOC_FREE(ctx);
  55                 return False;
  56         }
  57
  58         if((fd = sys_open(tmpname, O_RDWR|O_CREAT|O_EXCL|O_TRUNC, 0600)) < 0) {
  59                 DEBUG(0,("check_kernel_oplocks: Unable to open temp test file "
  60                          "%s. Error was %s\n",
  61                          tmpname, strerror(errno) ));
  62                 unlink( tmpname );
  63                 close(pfd[0]);
  64                 close(pfd[1]);
  65                 TALLOC_FREE(ctx);
  66                 return False;
  67         }
  68
  69         unlink(tmpname);
  70
  71         TALLOC_FREE(ctx);
  72
  73         if(sys_fcntl_long(fd, F_OPLKREG, pfd[1]) == -1) {
  74                 DEBUG(0,("check_kernel_oplocks: Kernel oplocks are not "
  75                          "available on this machine. Disabling kernel oplock "
  76                          "support.\n" ));
  77                 close(pfd[0]);
  78                 close(pfd[1]);
  79                 close(fd);
  80                 return False;
  81         }
  82
  83         if(sys_fcntl_long(fd, F_OPLKACK, OP_REVOKE) < 0 ) {
  84                 DEBUG(0,("check_kernel_oplocks: Error when removing kernel "
  85                          "oplock. Error was %s. Disabling kernel oplock "
  86                          "support.\n", strerror(errno) ));
  87                 close(pfd[0]);
  88                 close(pfd[1]);
  89                 close(fd);
  90                 return False;
  91         }
  92
  93         close(pfd[0]);
  94         close(pfd[1]);
  95         close(fd);
  96
  97         return True;
  98 }
  99
 100 /****************************************************************************
 101  * Deal with the IRIX kernel <--> smbd
 102  * oplock break protocol.
 103 ****************************************************************************/
 104
 105 static files_struct *irix_oplock_receive_message(fd_set *fds)
 106 {
 107         oplock_stat_t os;
 108         char dummy;
 109         struct file_id fileid;
 110         files_struct *fsp;
 111
 112         /* Ensure we only get one call per select fd set. */
 113         FD_CLR(oplock_pipe_read, fds);
 114
 115         /*
 116          * Read one byte of zero to clear the
 117          * kernel break notify message.
 118          */
 119
 120         if(read(oplock_pipe_read, &dummy, 1) != 1) {
 121                 DEBUG(0,("irix_oplock_receive_message: read of kernel "
 122                          "notification failed. Error was %s.\n",
 123                          strerror(errno) ));
 124                 return NULL;
 125         }
 126
 127         /*
 128          * Do a query to get the
 129          * device and inode of the file that has the break
 130          * request outstanding.
 131          */
 132
 133         if(sys_fcntl_ptr(oplock_pipe_read, F_OPLKSTAT, &os) < 0) {
 134                 DEBUG(0,("irix_oplock_receive_message: fcntl of kernel "
 135                          "notification failed. Error was %s.\n",
 136                          strerror(errno) ));
 137                 if(errno == EAGAIN) {
 138                         /*
 139                          * Duplicate kernel break message - ignore.
 140                          */
 141                         return NULL;
 142                 }
 143                 return NULL;
 144         }
 145
 146         /*
 147          * We only have device and inode info here - we have to guess that this
 148          * is the first fsp open with this dev,ino pair.
 149          *
 150          * NOTE: this doesn't work if any VFS modules overloads
 151          *       the file_id_create() hook!
 152          */
 153
 154         fileid = file_id_create_dev((SMB_DEV_T)os.os_dev,
 155                                     (SMB_INO_T)os.os_ino);
 156         if ((fsp = file_find_di_first(fileid)) == NULL) {
 157                 DEBUG(0,("irix_oplock_receive_message: unable to find open "
 158                          "file with dev = %x, inode = %.0f\n",
 159                          (unsigned int)os.os_dev, (double)os.os_ino ));
 160                 return NULL;
 161         }
 162
 163         DEBUG(5,("irix_oplock_receive_message: kernel oplock break request "
 164                  "received for file_id %s gen_id = %ul",
 165                  file_id_string_tos(&fsp->file_id),
 166                  fsp->fh->gen_id ));
 167
 168         return fsp;
 169 }
 170
 171 /****************************************************************************
 172  Attempt to set an kernel oplock on a file.
 173 ****************************************************************************/
 174
 175 static bool irix_set_kernel_oplock(files_struct *fsp, int oplock_type)
 176 {
 177         if (sys_fcntl_long(fsp->fh->fd, F_OPLKREG, oplock_pipe_write) == -1) {
 178                 if(errno != EAGAIN) {
 179                         DEBUG(0,("irix_set_kernel_oplock: Unable to get "
 180                                  "kernel oplock on file %s, file_id %s "
 181                                  "gen_id = %ul. Error was %s\n",
 182                                  fsp->fsp_name, file_id_string_tos(&fsp->file_id),
 183                                  fsp->fh->gen_id,
 184                                  strerror(errno) ));
 185                 } else {
 186                         DEBUG(5,("irix_set_kernel_oplock: Refused oplock on "
 187                                  "file %s, fd = %d, file_id = %s, "
 188                                  "gen_id = %ul. Another process had the file "
 189                                  "open.\n",
 190                                  fsp->fsp_name, fsp->fh->fd,
 191                                  file_id_string_tos(&fsp->file_id),
 192                                  fsp->fh->gen_id ));
 193                 }
 194                 return False;
 195         }
 196
 197         DEBUG(10,("irix_set_kernel_oplock: got kernel oplock on file %s, file_id = %s "
 198                   "gen_id = %ul\n",
 199                   fsp->fsp_name, file_id_string_tos(&fsp->file_id),
 200                   fsp->fh->gen_id));
 201
 202         return True;
 203 }
 204
 205 /****************************************************************************
 206  Release a kernel oplock on a file.
 207 ****************************************************************************/
 208
 209 static void irix_release_kernel_oplock(files_struct *fsp)
 210 {
 211         if (DEBUGLVL(10)) {
 212                 /*
 213                  * Check and print out the current kernel
 214                  * oplock state of this file.
 215                  */
 216                 int state = sys_fcntl_long(fsp->fh->fd, F_OPLKACK, -1);
 217                 dbgtext("irix_release_kernel_oplock: file %s, file_id = %s"
 218                         "gen_id = %ul, has kernel oplock state "
 219                         "of %x.\n", fsp->fsp_name, file_id_string_tos(&fsp->file_id),
 220                         fsp->fh->gen_id, state );
 221         }
 222
 223         /*
 224          * Remove the kernel oplock on this file.
 225          */
 226         if(sys_fcntl_long(fsp->fh->fd, F_OPLKACK, OP_REVOKE) < 0) {
 227                 if( DEBUGLVL( 0 )) {
 228                         dbgtext("irix_release_kernel_oplock: Error when "
 229                                 "removing kernel oplock on file " );
 230                         dbgtext("%s, file_id = %s gen_id = %ul. "
 231                                 "Error was %s\n",
 232                                 fsp->fsp_name, file_id_string_tos(&fsp->file_id),
 233                                 fsp->fh->gen_id,
 234                                 strerror(errno) );
 235                 }
 236         }
 237 }
 238
 239 /****************************************************************************
 240  See if there is a message waiting in this fd set.
 241  Note that fds MAY BE NULL ! If so we must do our own select.
 242 ****************************************************************************/
 243
 244 static bool irix_oplock_msg_waiting(fd_set *fds)
 245 {
 246         int selrtn;
 247         fd_set myfds;
 248         struct timeval to;
 249
 250         if (oplock_pipe_read == -1)
 251                 return False;
 252
 253         if (fds) {
 254                 return FD_ISSET(oplock_pipe_read, fds);
 255         }
 256
 257         /* Do a zero-time select. We just need to find out if there
 258          * are any outstanding messages. We use sys_select_intr as
 259          * we need to ignore any signals. */
 260
 261         FD_ZERO(&myfds);
 262         FD_SET(oplock_pipe_read, &myfds);
 263
 264         to = timeval_set(0, 0);
 265         selrtn = sys_select_intr(oplock_pipe_read+1,&myfds,NULL,NULL,&to);
 266         return (selrtn == 1) ? True : False;
 267 }
 268
 269 /****************************************************************************
 270  Setup kernel oplocks.
 271 ****************************************************************************/
 272
 273 struct kernel_oplocks *irix_init_kernel_oplocks(void)
 274 {
 275         int pfd[2];
 276         static struct kernel_oplocks koplocks;
 277
 278         if (!irix_oplocks_available())
 279                 return NULL;
 280
 281         if(pipe(pfd) != 0) {
 282                 DEBUG(0,("setup_kernel_oplock_pipe: Unable to create pipe. "
 283                          "Error was %s\n", strerror(errno) ));
 284                 return False;
 285         }
 286
 287         oplock_pipe_read = pfd[0];
 288         oplock_pipe_write = pfd[1];
 289
 290         koplocks.receive_message = irix_oplock_receive_message;
 291         koplocks.set_oplock = irix_set_kernel_oplock;
 292         koplocks.release_oplock = irix_release_kernel_oplock;
 293         koplocks.msg_waiting = irix_oplock_msg_waiting;
 294         koplocks.notification_fd = oplock_pipe_read;
 295
 296         return &koplocks;
 297 }
 298 #else
 299  void oplock_irix_dummy(void);
 300  void oplock_irix_dummy(void) {}
 301 #endif /* HAVE_KERNEL_OPLOCKS_IRIX */