src/filelock.cpp

   1 /* $Id: filelock-posix.cpp 23517 2007-08-07 17:07:59Z umoeller $ */
   2 /** @file
   3  * innotek Portable Runtime - File Locking, POSIX.
   4  */
   5
   6 /*
   7  * Copyright (C) 2006-2007 innotek GmbH
   8  *
   9  * This file is part of VirtualBox Open Source Edition (OSE), as
  10  * available from http://www.virtualbox.org. This file is free software;
  11  * you can redistribute it and/or modify it under the terms of the GNU
  12  * General Public License as published by the Free Software Foundation,
  13  * in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
  14  * distribution. VirtualBox OSE is distributed in the hope that it will
  15  * be useful, but WITHOUT ANY WARRANTY of any kind.
  16  */
  17
  18
  19 /*******************************************************************************
  20 *   Header Files                                                               *
  21 *******************************************************************************/
  22 #define LOG_GROUP RTLOGGROUP_FILE
  23
  24 #include <errno.h>
  25 #include <sys/types.h>
  26 #include <sys/ioctl.h>
  27 #include <sys/fcntl.h>
  28 #include <fcntl.h>
  29 #include <unistd.h>
  30 #include <sys/time.h>
  31
  32 #include "file.h"
  33 #include "func_defines.h"
  34 #include "const_defines.h"
  35 #include "fs.h"
  36 #include "RTErrConvertFromErrno.h"
  37
  38
  39
  40 int  RTFileLock(RTFILE File, unsigned fLock, int64_t offLock, uint64_t cbLock)
  41 {
  42     Assert(offLock >= 0);
  43
  44     /* Check arguments. */
  45     if (fLock & ~RTFILE_LOCK_MASK)
  46     {
  47         AssertMsgFailed(("Invalid fLock=%08X\n", fLock));
  48         return VERR_INVALID_PARAMETER;
  49     }
  50
  51     /*
  52      * Validate offset.
  53      */
  54     if (    sizeof(off_t) < sizeof(cbLock)
  55         &&  (    (offLock >> 32) != 0
  56              ||  (cbLock >> 32) != 0
  57              ||  ((offLock + cbLock) >> 32) != 0))
  58     {
  59         AssertMsgFailed(("64-bit file i/o not supported! offLock=%lld cbLock=%lld\n", offLock, cbLock));
  60         return VERR_NOT_SUPPORTED;
  61     }
  62
  63     /* Prepare flock structure. */
  64     struct flock fl;
  65     Assert(RTFILE_LOCK_WRITE);
  66     fl.l_type   = (fLock & RTFILE_LOCK_WRITE) ? F_WRLCK : F_RDLCK;
  67     fl.l_whence = SEEK_SET;
  68     fl.l_start  = (off_t)offLock;
  69     fl.l_len    = (off_t)cbLock;
  70     fl.l_pid    = 0;
  71
  72     Assert(RTFILE_LOCK_WAIT);
  73     if (fcntl(File, (fLock & RTFILE_LOCK_WAIT) ? F_SETLKW : F_SETLK, &fl) >= 0)
  74         return VINF_SUCCESS;
  75
  76     int iErr = errno;
  77     if (    iErr == EAGAIN
  78         ||  iErr == EACCES)
  79         return VERR_FILE_LOCK_VIOLATION;
  80
  81     return RTErrConvertFromErrno(iErr);
  82 }
  83
  84
  85 int  RTFileChangeLock(RTFILE File, unsigned fLock, int64_t offLock, uint64_t cbLock)
  86 {
  87     /** @todo We never returns VERR_FILE_NOT_LOCKED for now. */
  88     return RTFileLock(File, fLock, offLock, cbLock);
  89 }
  90
  91
  92 int  RTFileUnlock(RTFILE File, int64_t offLock, uint64_t cbLock)
  93 {
  94     Assert(offLock >= 0);
  95
  96     /*
  97      * Validate offset.
  98      */
  99     if (    sizeof(off_t) < sizeof(cbLock)
 100         &&  (    (offLock >> 32) != 0
 101              ||  (cbLock >> 32) != 0
 102              ||  ((offLock + cbLock) >> 32) != 0))
 103     {
 104         AssertMsgFailed(("64-bit file i/o not supported! offLock=%lld cbLock=%lld\n", offLock, cbLock));
 105         return VERR_NOT_SUPPORTED;
 106     }
 107
 108     /* Prepare flock structure. */
 109     struct flock fl;
 110     fl.l_type   = F_UNLCK;
 111     fl.l_whence = SEEK_SET;
 112     fl.l_start  = (off_t)offLock;
 113     fl.l_len    = (off_t)cbLock;
 114     fl.l_pid    = 0;
 115
 116     if (fcntl(File, F_SETLK, &fl) >= 0)
 117         return VINF_SUCCESS;
 118
 119     /* @todo check error codes for non existing lock. */
 120     int iErr = errno;
 121     if (    iErr == EAGAIN
 122         ||  iErr == EACCES)
 123         return VERR_FILE_LOCK_VIOLATION;
 124
 125     return RTErrConvertFromErrno(iErr);
 126 }
 127
 128