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