smbd/oplock_irix.c

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/*
   Unix SMB/CIFS implementation.
   IRIX kernel oplock processing
   Copyright (C) Andrew Tridgell 1992-1998
   
   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.
*/

#define DBGC_CLASS DBGC_LOCKING
#include "includes.h"

#if HAVE_KERNEL_OPLOCKS_IRIX

static int oplock_pipe_write = -1;
static int oplock_pipe_read = -1;

/****************************************************************************
 Test to see if IRIX kernel oplocks work.
****************************************************************************/

static BOOL irix_oplocks_available(void)
{
        int fd;
        int pfd[2];
        pstring tmpname;

        set_effective_capability(KERNEL_OPLOCK_CAPABILITY);

        slprintf(tmpname,sizeof(tmpname)-1, "%s/koplock.%d", lp_lockdir(),
                 (int)sys_getpid());

        if(pipe(pfd) != 0) {
                DEBUG(0,("check_kernel_oplocks: Unable to create pipe. Error "
                         "was %s\n",
                         strerror(errno) ));
                return False;
        }

        if((fd = sys_open(tmpname, O_RDWR|O_CREAT|O_EXCL|O_TRUNC, 0600)) < 0) {
                DEBUG(0,("check_kernel_oplocks: Unable to open temp test file "
                         "%s. Error was %s\n",
                         tmpname, strerror(errno) ));
                unlink( tmpname );
                close(pfd[0]);
                close(pfd[1]);
                return False;
        }

        unlink(tmpname);

        if(sys_fcntl_long(fd, F_OPLKREG, pfd[1]) == -1) {
                DEBUG(0,("check_kernel_oplocks: Kernel oplocks are not "
                         "available on this machine. Disabling kernel oplock "
                         "support.\n" ));
                close(pfd[0]);
                close(pfd[1]);
                close(fd);
                return False;
        }

        if(sys_fcntl_long(fd, F_OPLKACK, OP_REVOKE) < 0 ) {
                DEBUG(0,("check_kernel_oplocks: Error when removing kernel "
                         "oplock. Error was %s. Disabling kernel oplock "
                         "support.\n", strerror(errno) ));
                close(pfd[0]);
                close(pfd[1]);
                close(fd);
                return False;
        }

        close(pfd[0]);
        close(pfd[1]);
        close(fd);

        return True;
}

/****************************************************************************
 * Deal with the IRIX kernel <--> smbd
 * oplock break protocol.
****************************************************************************/

static files_struct *irix_oplock_receive_message(fd_set *fds)
{
        extern int smb_read_error;
        oplock_stat_t os;
        char dummy;
        files_struct *fsp;

        /* Ensure we only get one call per select fd set. */
        FD_CLR(oplock_pipe_read, fds);

        /*
         * Read one byte of zero to clear the
         * kernel break notify message.
         */

        if(read(oplock_pipe_read, &dummy, 1) != 1) {
                DEBUG(0,("irix_oplock_receive_message: read of kernel "
                         "notification failed. Error was %s.\n",
                         strerror(errno) ));
                smb_read_error = READ_ERROR;
                return NULL;
        }

        /*
         * Do a query to get the
         * device and inode of the file that has the break
         * request outstanding.
         */

        if(sys_fcntl_ptr(oplock_pipe_read, F_OPLKSTAT, &os) < 0) {
                DEBUG(0,("irix_oplock_receive_message: fcntl of kernel "
                         "notification failed. Error was %s.\n",
                         strerror(errno) ));
                if(errno == EAGAIN) {
                        /*
                         * Duplicate kernel break message - ignore.
                         */
                        return NULL;
                }
                smb_read_error = READ_ERROR;
                return NULL;
        }

        /*
         * We only have device and inode info here - we have to guess that this
         * is the first fsp open with this dev,ino pair.
         */

        if ((fsp = file_find_di_first((SMB_DEV_T)os.os_dev,
                                      (SMB_INO_T)os.os_ino)) == NULL) {
                DEBUG(0,("irix_oplock_receive_message: unable to find open "
                         "file with dev = %x, inode = %.0f\n",
                         (unsigned int)os.os_dev, (double)os.os_ino ));
                return NULL;
        }
     
        DEBUG(5,("irix_oplock_receive_message: kernel oplock break request "
                 "received for dev = %x, inode = %.0f\n, file_id = %ul",
                 (unsigned int)fsp->dev, (double)fsp->inode,
                 fsp->fh->file_id ));

        return fsp;
}

/****************************************************************************
 Attempt to set an kernel oplock on a file.
****************************************************************************/

static BOOL irix_set_kernel_oplock(files_struct *fsp, int oplock_type)
{
        if (sys_fcntl_long(fsp->fh->fd, F_OPLKREG, oplock_pipe_write) == -1) {
                if(errno != EAGAIN) {
                        DEBUG(0,("irix_set_kernel_oplock: Unable to get "
                                 "kernel oplock on file %s, dev = %x, inode "
                                 "= %.0f, file_id = %ul. Error was %s\n", 
                                 fsp->fsp_name, (unsigned int)fsp->dev,
                                 (double)fsp->inode, fsp->fh->file_id,
                                 strerror(errno) ));
                } else {
                        DEBUG(5,("irix_set_kernel_oplock: Refused oplock on "
                                 "file %s, fd = %d, dev = %x, inode = %.0f, "
                                 "file_id = %ul. Another process had the file "
                                 "open.\n",
                                 fsp->fsp_name, fsp->fh->fd,
                                 (unsigned int)fsp->dev, (double)fsp->inode,
                                 fsp->fh->file_id ));
                }
                return False;
        }
        
        DEBUG(10,("irix_set_kernel_oplock: got kernel oplock on file %s, dev "
                  "= %x, inode = %.0f, file_id = %ul\n",
                  fsp->fsp_name, (unsigned int)fsp->dev, (double)fsp->inode,
                  fsp->fh->file_id));

        return True;
}

/****************************************************************************
 Release a kernel oplock on a file.
****************************************************************************/

static void irix_release_kernel_oplock(files_struct *fsp)
{
        if (DEBUGLVL(10)) {
                /*
                 * Check and print out the current kernel
                 * oplock state of this file.
                 */
                int state = sys_fcntl_long(fsp->fh->fd, F_OPLKACK, -1);
                dbgtext("irix_release_kernel_oplock: file %s, dev = %x, "
                        "inode = %.0f file_id = %ul, has kernel oplock state "
                        "of %x.\n", fsp->fsp_name, (unsigned int)fsp->dev,
                        (double)fsp->inode, fsp->fh->file_id, state );
        }

        /*
         * Remove the kernel oplock on this file.
         */
        if(sys_fcntl_long(fsp->fh->fd, F_OPLKACK, OP_REVOKE) < 0) {
                if( DEBUGLVL( 0 )) {
                        dbgtext("irix_release_kernel_oplock: Error when "
                                "removing kernel oplock on file " );
                        dbgtext("%s, dev = %x, inode = %.0f, file_id = %ul. "
                                "Error was %s\n",
                                fsp->fsp_name, (unsigned int)fsp->dev, 
                                (double)fsp->inode, fsp->fh->file_id,
                                strerror(errno) );
                }
        }
}

/****************************************************************************
 See if there is a message waiting in this fd set.
 Note that fds MAY BE NULL ! If so we must do our own select.
****************************************************************************/

static BOOL irix_oplock_msg_waiting(fd_set *fds)
{
        int selrtn;
        fd_set myfds;
        struct timeval to;

        if (oplock_pipe_read == -1)
                return False;

        if (fds) {
                return FD_ISSET(oplock_pipe_read, fds);
        }

        /* Do a zero-time select. We just need to find out if there
         * are any outstanding messages. We use sys_select_intr as
         * we need to ignore any signals. */

        FD_ZERO(&myfds);
        FD_SET(oplock_pipe_read, &myfds);

        to = timeval_set(0, 0);
        selrtn = sys_select_intr(oplock_pipe_read+1,&myfds,NULL,NULL,&to);
        return (selrtn == 1) ? True : False;
}

/****************************************************************************
 Setup kernel oplocks.
****************************************************************************/

struct kernel_oplocks *irix_init_kernel_oplocks(void) 
{
        int pfd[2];
        static struct kernel_oplocks koplocks;

        if (!irix_oplocks_available())
                return NULL;

        if(pipe(pfd) != 0) {
                DEBUG(0,("setup_kernel_oplock_pipe: Unable to create pipe. "
                         "Error was %s\n", strerror(errno) ));
                return False;
        }

        oplock_pipe_read = pfd[0];
        oplock_pipe_write = pfd[1];

        koplocks.receive_message = irix_oplock_receive_message;
        koplocks.set_oplock = irix_set_kernel_oplock;
        koplocks.release_oplock = irix_release_kernel_oplock;
        koplocks.msg_waiting = irix_oplock_msg_waiting;
        koplocks.notification_fd = oplock_pipe_read;

        return &koplocks;
}
#else
 void oplock_irix_dummy(void);
 void oplock_irix_dummy(void) {}
#endif /* HAVE_KERNEL_OPLOCKS_IRIX */

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