source3/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 #include "system/filesys.h"
  23 #include "smbd/smbd.h"
  24 #include "smbd/globals.h"
  25
  26 #if HAVE_KERNEL_OPLOCKS_IRIX
  27
  28 struct irix_oplocks_context {
  29         struct kernel_oplocks *ctx;
  30         struct smbd_server_connection *sconn;
  31         int write_fd;
  32         int read_fd;
  33         struct tevent_fd *read_fde;
  34         bool pending;
  35 };
  36
  37 /****************************************************************************
  38  Test to see if IRIX kernel oplocks work.
  39 ****************************************************************************/
  40
  41 static bool irix_oplocks_available(void)
  42 {
  43         int fd;
  44         int pfd[2];
  45         TALLOC_CTX *ctx = talloc_stackframe();
  46         char *tmpname = NULL;
  47
  48         set_effective_capability(KERNEL_OPLOCK_CAPABILITY);
  49
  50         tmpname = talloc_asprintf(ctx,
  51                                 "%s/koplock.%d",
  52                                 lp_lockdir(),
  53                                 (int)getpid());
  54         if (!tmpname) {
  55                 TALLOC_FREE(ctx);
  56                 return False;
  57         }
  58
  59         if(pipe(pfd) != 0) {
  60                 DEBUG(0,("check_kernel_oplocks: Unable to create pipe. Error "
  61                          "was %s\n",
  62                          strerror(errno) ));
  63                 TALLOC_FREE(ctx);
  64                 return False;
  65         }
  66
  67         if((fd = open(tmpname, O_RDWR|O_CREAT|O_EXCL|O_TRUNC, 0600)) < 0) {
  68                 DEBUG(0,("check_kernel_oplocks: Unable to open temp test file "
  69                          "%s. Error was %s\n",
  70                          tmpname, strerror(errno) ));
  71                 unlink( tmpname );
  72                 close(pfd[0]);
  73                 close(pfd[1]);
  74                 TALLOC_FREE(ctx);
  75                 return False;
  76         }
  77
  78         unlink(tmpname);
  79
  80         TALLOC_FREE(ctx);
  81
  82         if(sys_fcntl_long(fd, F_OPLKREG, pfd[1]) == -1) {
  83                 DEBUG(0,("check_kernel_oplocks: Kernel oplocks are not "
  84                          "available on this machine. Disabling kernel oplock "
  85                          "support.\n" ));
  86                 close(pfd[0]);
  87                 close(pfd[1]);
  88                 close(fd);
  89                 return False;
  90         }
  91
  92         if(sys_fcntl_long(fd, F_OPLKACK, OP_REVOKE) < 0 ) {
  93                 DEBUG(0,("check_kernel_oplocks: Error when removing kernel "
  94                          "oplock. Error was %s. Disabling kernel oplock "
  95                          "support.\n", strerror(errno) ));
  96                 close(pfd[0]);
  97                 close(pfd[1]);
  98                 close(fd);
  99                 return False;
 100         }
 101
 102         close(pfd[0]);
 103         close(pfd[1]);
 104         close(fd);
 105
 106         return True;
 107 }
 108
 109 /*
 110  * This is bad because the file_id should always be created through the vfs
 111  * layer!  Unfortunately, a conn struct isn't available here.
 112  */
 113 static struct file_id file_id_create_dev(SMB_DEV_T dev, SMB_INO_T inode)
 114 {
 115         struct file_id key;
 116
 117         /* the ZERO_STRUCT ensures padding doesn't break using the key as a
 118          * blob */
 119         ZERO_STRUCT(key);
 120
 121         key.devid = dev;
 122         key.inode = inode;
 123
 124         return key;
 125 }
 126
 127 /****************************************************************************
 128  * Deal with the IRIX kernel <--> smbd
 129  * oplock break protocol.
 130 ****************************************************************************/
 131
 132 static files_struct *irix_oplock_receive_message(struct kernel_oplocks *_ctx)
 133 {
 134         struct irix_oplocks_context *ctx = talloc_get_type(_ctx->private_data,
 135                                            struct irix_oplocks_context);
 136         oplock_stat_t os;
 137         char dummy;
 138         struct file_id fileid;
 139         files_struct *fsp;
 140
 141         /*
 142          * TODO: is it correct to assume we only get one
 143          * oplock break, for each byte we read from the pipe?
 144          */
 145         ctx->pending = false;
 146
 147         /*
 148          * Read one byte of zero to clear the
 149          * kernel break notify message.
 150          */
 151
 152         if(read(ctx->read_fd, &dummy, 1) != 1) {
 153                 DEBUG(0,("irix_oplock_receive_message: read of kernel "
 154                          "notification failed. Error was %s.\n",
 155                          strerror(errno) ));
 156                 return NULL;
 157         }
 158
 159         /*
 160          * Do a query to get the
 161          * device and inode of the file that has the break
 162          * request outstanding.
 163          */
 164
 165         if(sys_fcntl_ptr(ctx->read_fd, F_OPLKSTAT, &os) < 0) {
 166                 DEBUG(0,("irix_oplock_receive_message: fcntl of kernel "
 167                          "notification failed. Error was %s.\n",
 168                          strerror(errno) ));
 169                 if(errno == EAGAIN) {
 170                         /*
 171                          * Duplicate kernel break message - ignore.
 172                          */
 173                         return NULL;
 174                 }
 175                 return NULL;
 176         }
 177
 178         /*
 179          * We only have device and inode info here - we have to guess that this
 180          * is the first fsp open with this dev,ino pair.
 181          *
 182          * NOTE: this doesn't work if any VFS modules overloads
 183          *       the file_id_create() hook!
 184          */
 185
 186         fileid = file_id_create_dev((SMB_DEV_T)os.os_dev,
 187                                     (SMB_INO_T)os.os_ino);
 188         if ((fsp = file_find_di_first(ctx->sconn, fileid)) == NULL) {
 189                 DEBUG(0,("irix_oplock_receive_message: unable to find open "
 190                          "file with dev = %x, inode = %.0f\n",
 191                          (unsigned int)os.os_dev, (double)os.os_ino ));
 192                 return NULL;
 193         }
 194
 195         DEBUG(5,("irix_oplock_receive_message: kernel oplock break request "
 196                  "received for file_id %s gen_id = %ul",
 197                  file_id_string_tos(&fsp->file_id),
 198                  fsp->fh->gen_id ));
 199
 200         return fsp;
 201 }
 202
 203 /****************************************************************************
 204  Attempt to set an kernel oplock on a file.
 205 ****************************************************************************/
 206
 207 static bool irix_set_kernel_oplock(struct kernel_oplocks *_ctx,
 208                                    files_struct *fsp, int oplock_type)
 209 {
 210         struct irix_oplocks_context *ctx = talloc_get_type(_ctx->private_data,
 211                                            struct irix_oplocks_context);
 212
 213         if (sys_fcntl_long(fsp->fh->fd, F_OPLKREG, ctx->write_fd) == -1) {
 214                 if(errno != EAGAIN) {
 215                         DEBUG(0,("irix_set_kernel_oplock: Unable to get "
 216                                  "kernel oplock on file %s, file_id %s "
 217                                  "gen_id = %ul. Error was %s\n",
 218                                  fsp_str_dbg(fsp),
 219                                  file_id_string_tos(&fsp->file_id),
 220                                  fsp->fh->gen_id,
 221                                  strerror(errno) ));
 222                 } else {
 223                         DEBUG(5,("irix_set_kernel_oplock: Refused oplock on "
 224                                  "file %s, fd = %d, file_id = %s, "
 225                                  "gen_id = %ul. Another process had the file "
 226                                  "open.\n",
 227                                  fsp_str_dbg(fsp), fsp->fh->fd,
 228                                  file_id_string_tos(&fsp->file_id),
 229                                  fsp->fh->gen_id ));
 230                 }
 231                 return False;
 232         }
 233
 234         DEBUG(10,("irix_set_kernel_oplock: got kernel oplock on file %s, file_id = %s "
 235                   "gen_id = %ul\n",
 236                   fsp_str_dbg(fsp), file_id_string_tos(&fsp->file_id),
 237                   fsp->fh->gen_id));
 238
 239         return True;
 240 }
 241
 242 /****************************************************************************
 243  Release a kernel oplock on a file.
 244 ****************************************************************************/
 245
 246 static void irix_release_kernel_oplock(struct kernel_oplocks *_ctx,
 247                                        files_struct *fsp, int oplock_type)
 248 {
 249         if (DEBUGLVL(10)) {
 250                 /*
 251                  * Check and print out the current kernel
 252                  * oplock state of this file.
 253                  */
 254                 int state = sys_fcntl_long(fsp->fh->fd, F_OPLKACK, -1);
 255                 dbgtext("irix_release_kernel_oplock: file %s, file_id = %s"
 256                         "gen_id = %ul, has kernel oplock state "
 257                         "of %x.\n", fsp_str_dbg(fsp),
 258                         file_id_string_tos(&fsp->file_id),
 259                         fsp->fh->gen_id, state );
 260         }
 261
 262         /*
 263          * Remove the kernel oplock on this file.
 264          */
 265         if(sys_fcntl_long(fsp->fh->fd, F_OPLKACK, OP_REVOKE) < 0) {
 266                 if( DEBUGLVL( 0 )) {
 267                         dbgtext("irix_release_kernel_oplock: Error when "
 268                                 "removing kernel oplock on file " );
 269                         dbgtext("%s, file_id = %s gen_id = %ul. "
 270                                 "Error was %s\n",
 271                                 fsp_str_dbg(fsp),
 272                                 file_id_string_tos(&fsp->file_id),
 273                                 fsp->fh->gen_id,
 274                                 strerror(errno) );
 275                 }
 276         }
 277 }
 278
 279 static void irix_oplocks_read_fde_handler(struct tevent_context *ev,
 280                                           struct tevent_fd *fde,
 281                                           uint16_t flags,
 282                                           void *private_data)
 283 {
 284         struct irix_oplocks_context *ctx = talloc_get_type(private_data,
 285                                            struct irix_oplocks_context);
 286         files_struct *fsp;
 287
 288         fsp = irix_oplock_receive_message(ctx->ctx);
 289         break_kernel_oplock(ctx->sconn->msg_ctx, fsp);
 290 }
 291
 292 /****************************************************************************
 293  Setup kernel oplocks.
 294 ****************************************************************************/
 295
 296 static const struct kernel_oplocks_ops irix_koplocks = {
 297         .set_oplock                     = irix_set_kernel_oplock,
 298         .release_oplock                 = irix_release_kernel_oplock,
 299         .contend_level2_oplocks_begin   = NULL,
 300         .contend_level2_oplocks_end     = NULL,
 301 };
 302
 303 struct kernel_oplocks *irix_init_kernel_oplocks(struct smbd_server_connection *sconn)
 304 {
 305         struct kernel_oplocks *_ctx;
 306         struct irix_oplocks_context *ctx;
 307         int pfd[2];
 308
 309         if (!irix_oplocks_available())
 310                 return NULL;
 311
 312         _ctx = talloc_zero(sconn, struct kernel_oplocks);
 313         if (!_ctx) {
 314                 return NULL;
 315         }
 316
 317         ctx = talloc_zero(_ctx, struct irix_oplocks_context);
 318         if (!ctx) {
 319                 talloc_free(_ctx);
 320                 return NULL;
 321         }
 322         _ctx->ops = &irix_koplocks;
 323         _ctx->private_data = ctx;
 324         ctx->ctx = _ctx;
 325         ctx->sconn = sconn;
 326
 327         if(pipe(pfd) != 0) {
 328                 talloc_free(_ctx);
 329                 DEBUG(0,("setup_kernel_oplock_pipe: Unable to create pipe. "
 330                          "Error was %s\n", strerror(errno) ));
 331                 return False;
 332         }
 333
 334         ctx->read_fd = pfd[0];
 335         ctx->write_fd = pfd[1];
 336
 337         ctx->read_fde = tevent_add_fd(sconn->ev_ctx,
 338                                      ctx,
 339                                      ctx->read_fd,
 340                                      TEVENT_FD_READ,
 341                                      irix_oplocks_read_fde_handler,
 342                                      ctx);
 343         return _ctx;
 344 }
 345 #else
 346  void oplock_irix_dummy(void);
 347  void oplock_irix_dummy(void) {}
 348 #endif /* HAVE_KERNEL_OPLOCKS_IRIX */