dosfslib.c

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/* dosFsLib.c - MS-DOS media-compatible file system library */

/* Copyright 1984-1998 Wind River Systems, Inc. */
#include "copyright_wrs.h"

/*
modification history
--------------------
03l,16mar99,dgp  doc: revised dosFsVolUnmount()/usrFdConfig() note (SPR 22068)
03k,14mar99,jdi  doc: removed refs to config.h and/or configAll.h (SPR 25663).
03j,23feb99,dgp  add note not to use dosFsVolUnmount() with usrFdConfig()
03i,21feb99,jdi  listed errnos.
03h,30sep98,ms   removed calls to DOS_DEBUG_MSG
03g,29sep98,lrn  checked-in md3's and previous SPR fixes into T2.0 view
05f,17sep98,md3  spr22406: race in dosFs mem management, changed
		 dosFsMemPartId options to MEM_BLOCK_ERROR_LOG_FLAG.
		 Added dosFsMemPartIdOptions, dosFsMemPartInitSize,
		 dosFsMemPartGrowSize, dosFsMemPartCap.
		 Added calls to DOS_DEBUG_MSG, macro in dosFsLib.h.
05e,11sep98,md3  spr22318: workAround for SPR22354, memPartFindMax.
05d,31jul98,jkf  official patch release fixes SPRs:
                 21475, 9465, 4061, 8721, 9057, 9224, 5282, and 8038.
                 Also provides partial relief for SPRs 20683 and 9911, 
                 only for customers NOT NFS exporting the file system.
05c,31jul98,jkf  added (USHORT *)'s to dosFsVolMount() to fix SPR#9224.
05b,17may98,lrn  added local memory pool to fight fragmentation (SPR# 9465),
		 fixed USWAB[SL] for aligned LE marchitecture (SPR#21475)
05a,07oct97,wil  added call to the block device ioctl routine with 'FIOFLUSH' 
                 command when an user issues a 'FIOFLUSH' or 'FIOSYNC' ioctl 
                 command to the DosFsLib (SPR 4061);
                 fixed dosFsDevInit() makes memPartFree error (SPR 8721);
                 fixed dosFsRename( dir -> dir ) (SPR 9057);
    	    	 fixed bug of 255 sectors-per-cluster (SPR 5282);
                 fixed bug of double inserting of directory into hash. (SPR 8038)
04f,05mar98,yp   conditionalized reserved field usage to EXPORT_ENABLED so that
                 it only happens if nfsd is active.  This provides partial relief 
                 for SPRs 20683 and 9911, only for customers NOT exporting the FS. 
04e,28feb97,tam  fixed dosFsIoctl(FIOTIMESET) (SPR 8080).
04d,21feb97,tam  fixed dosFsRename() if renaming entry to another dir.(SPR 8038)
04c,10oct96,kdl  use UINT8 for secPerClust (SPR 4284); use localtime_r() in 
		 dosFsTimeAnsiToDos() (SPR 4443); use unsigned format in 
		 dosFsConfigShow() (SPR 4472); don't count deleted root entries 
		 (SPR 4624, 4873); handle large clusters in dosFsClustInit() 
		 (SPR 4672); maintain free clust count in vol desc (SPR 4708);
		 initialize hash key name (SPR 4791); zero out alloc'd contig 
		 clusters (SPR 5030); replace hash entries during contig alloc 
		 (SPR 5520); mount disk during dosFsConfigGet() and 
		 ioctl(FIONFREE) (SPR 5598); check for single-cluster file 
		 during FIOTRUNC (SPR 5781); prevent search past end of 
		 fatModTbl in dosFsFatFlush() (SPR 7253).
04b,16oct95,jdi  doc: FIORENAME now supports renaming directories (SPR 4345).
04a,06apr95,kdl  fix memory leak in dosFsDirFlush (SPR 4203).
03z,29mar95,kdl  removed obsolete stat structure fields; made secPerClust
		 unsigned for dosFsConfigInit(); changed dosFsMode to 
		 dosFsFileMode; remove root entry from hash tbl during mount;
		 added DOS_OPT_LOWERCASE; keep dosFsClustInit from overrunning
		 area to init; invalidate fd buffer if needed when truncating 
		 file.
03y,20mar95,jdi  doc addition about DOS_OPT_LOWERCASE as per kdl.
03x,27feb95,jdi  doc: format tweaks.
03w,27feb95,jdi  doc: changed dosFsMode to dosFsFileMode (doc only) (SPR 4085).
03v,16jan95,rhp  add info to doc of FIOTRUNC ioctl
03u,10dec94,kdl  add DOS_OPT_EXPORT to dosFsConfigShow()  (SPR 3839).
03t,05dec94,kdl  modify subdirectory entries when renaming directory (SPR 3832).
03s,03dec94,kdl  fixed loss of subdir contents when renamed to new dir SPR 3832.
03r,12nov94,kdl  re-worked export initialization; added dosFsDevInitOptionsSet()
		 made dosFsClustClustFind() only init new cluters if req'd;
		 made FIONFREE code use stored count; free file buffer earlier
		 during close; prevent useless reads in dosFsClustNew();
		 prevent dosFsVolInit() on write-protected disk; don't alloc
		 2 FAT buffers at once during VolInit; free cluster chain
		 during failed alloc; allow extension in dir names; check for
		 null BLK_DEV in dosFsMkfs(); free fd if dosFsCreate malloc 
		 fails; made fd position ptrs unsigned; allow std names starting
		 with "."; removed DOS_MAX_SEC_SIZE; allow rename of directory.
03m,27jul94,jmm  directory names can now have extensions (spr 2263)
03l,25jul94,jmm  added check for NULL ptr to dosFsMkfs
03q,08sep94,jmm  final NFS changes
03p,01jun94,jmm  Roland's doc changes
03o,19may94,jmm  fixed file truncation problem
03n,27apr94,jmm  NFS documentation added; user-selected file modes added
                 Parent directories now have timestamp incremented by 2
		     when files created or deleted
03m,20apr94,jmm  creating a file now increments the directory time
03l,19apr94,jmm  added support for NFS to dos file system
03k,31aug93,kdl  changed to use ANSI date/time format (SPR #2498).
03j,31aug93,kdl  added check for same device during dosFsDirMake() (SPR #2371).
03i,30aug93,kdl  changed FIOSYNC to re-read buffered cluster (SPR #2494).
03h,13aug93,kdl  clear root dir ptr if dosFsDirLoad() fails (SPR #1796).
03g,08jul93,kdl  fixed clobbering of data if root directory full (SPR #2104).
03f,27feb93,kdl  fixed bug which prevented files starting w/ "." (SPR #2023);
		 improved checks for invalid disk when mounting (SPR #2043).
03e,10feb93,jdi  more documentation cleanup for 5.1.
03d,08feb93,kdl  consolidated option fields in DOS_VOL_CONFIG and 
		 DOS_VOL_DESC; added dosFsVolOptionsGet(), dosFsVolOptionsSet(),
		 dosFsMkfsOptionsSet() (SPR #1871); made dosFsRename() delete 
		 existing file if renaming to another dir (SPR #1812);
		 minor changes to dosFsConfigShow() display format.
03c,01feb93,jdi  documentation cleanup for 5.1.
		 added third param to ioctl examples.
03b,15oct92,kdl  fixed incorrect semGive if trying to truncate read-only file
		 (SPR #1649).
03a,03oct92,kdl  removed NOMANUAL for dosFsConfigGet(), dosFsConfigShow();
		 added free space and max contig space to dosFsConfigShow().
02z,02oct92,srh  added ioctl(FIOGETFL) to return file's open mode
02y,30sep92,kdl  removed check for 8086 jump instr in boot sector during mount.
02x,16sep92,kdl  made disk clusters be correctly read in for files opened
		 O_WRONLY (SPR 963,1591); added S_dosFsLib_WRITE_ONLY.
02w,07sep92,smb  added blksize and blocks to the stat structure initialisation.
02v,31aug92,kdl  made FAT be flushed during FIOSYNC (SPR 1586); zero-out
		 new file clusters when allocated due to seek (SPR 1478);
		 don't return error if asked to read zero bytes (SPR 1544).
02u,30jul92,kdl  added missing semGive in dosFsDirRead() error handling.
02t,22jul92,kdl  changed from 4.0.2-style semaphores to mutexes; ansi cleanup.
02s,18jul92,smb  Changed errno.h to errnoLib.h.
02r,30jun92,kdl	 allow specification of max available when allocating
		 contiguous space; add ioctl(FIONCONTIG) to report max 
		 available contig space; allow file truncation via FIOTRUNC.
02q,23jun92,kdl  added long filename support; fixed dosFsVolInit to make
		 sure entire FAT is written out; misc. error handling fixes.
02p,26may92,rrr  the tree shuffle
02o,05may92,kdl	 restored 02m changes clobbered by 02n checkin; fixed mod hist.
02n,05may92,kdl  added selective FAT sector flushing.
02m,22apr92,yao  changed BYTE_ORDER to _BYTE_ORDER, BIG/LITTLE_ENDIAN to
		 _BIG/LITTLE_ENDIAN.  changed if CPUs to if _DYNAMIC_BUS_SIZING.
02l,10dec91,gae  added includes for ANSI.
02k,19nov91,rrr  shut up some ansi warnings.
02j,15oct91,caf  added MC68000 and MC68010 to USWAB category.
02i,10oct91,rrr  fixed syntax error!!!!!!!!!!
02h,09oct91,ajm  placed mips into USWAB catagory, was just SPARC, and made
		  line 7120 in dosFsVolMount USWAB as it should be
02g,04oct91,rrr  passed through the ansification filter
                  -changed functions to ansi style
		  -changed includes to have absolute path from h/
		  -fixed #else and #endif
		  -changed TINY and UTINY to INT8 and UINT8
		  -changed READ, WRITE and UPDATE to O_RDONLY O_WRONLY and ...
		  -changed VOID to void
		  -changed copyright notice
02f,24jul91,jcc  fixed byte-swapping macros for little endian machines.
02e,20jul91,del  added USAWB macros as per ajm for MIPS/SPARC.  Added little
		 endian byte swapping macros.  Integrated kdl's first pass at
		 type casting structure elements.
02d,13jun91,kdl  made memory be freed properly when deleting directory.
02c,30may91,wmd  enabled byte swapping macros for SPARC.
02b,22may91,jdi  documentation tweaks.
02a,26apr91,hdn  added defines and macros for TRON architecture.
01z,05apr91,jdi	 documentation -- removed header parens and x-ref numbers;
		 doc review by kdl.
01y,25mar91,del  added I960 defines for SWABx.
01x,13feb91,jaa	 documented ioctl functions.
01w,23jan91,kdl	 removed unnecessary \'s in printf formatting string.
01v,23jan91,jaa	 documentation.
01u,25oct90,kdl	 fixed problems with reading root dir larger than 1 sector;
		 made dosFsConfigShow() display default device name if used.
01t,19oct90,kdl	 changed dosFsConfigInit() to return STATUS; made changes to
		 set/handle archive bit in attribute byte for volume label;
		 added validation of config data during dosFsDevInit(); made
		 dosFsMkfs() calculate cluster size; added dosFsConfigGet()
		 and dosFsConfigShow(), both NOMANUAL.
01s,18sep90,kdl	 removed blank lines after mod history, for mangen.
01r,10aug90,kdl	 added forward declarations for functions returning void.
01q,09aug90,kdl	 changed name from msdosLib to dosFsLib.
01p,24jul90,kdl	 made error handling in msdosDevInit call iosDevDelete.
01o,19jul90,kdl	 mangen fixes.
01n,19jul90,kdl	 fixed possible null pointer problems in msdosDevInit.
01m,19jul90,kdl	 made msdosDevInit mount disk if no volume configuration given.
01l,12jul90,kdl	 made root dir be read from disk when listing dir; added
		 BLK_DEV statusChk routine hook.
01k,26jun90,jcf  changed semTake () calling sequeunce to clean up lint.
01j,22jun90,kdl	 added msdosConfigInit; documentation clean-up.
01i,14jun90,kdl	 made msdosCreate ignore only file-not-found error when
		 deleting existing file.  Added FIOUNMOUNT.
01h,10may90,kdl	 fixed msdosFdFree and msdosInit to set cluster field to NONE
		 for free Fd's; fixed problem in linkage for first root entry;
		 made various routines use pathCondense to avoid ".." problems;
		 added S_msdosLib_BAD_SEEK.
01g,07may90,kdl	 added POSIX directory handling, added BLK_DEV fields (bd_mode
		 and bd_readyChanged), fixed FIONFREE, fixed FIOSEEK, lint.
01f,03apr90,kdl	 made msdosRead read all requested bytes, made FIOFLUSH and
		 FIOSYNC the same, pathParse changes.
01e,23mar90,kdl	 lint, changed BLK_DEV field names, made msdosMkfs calculate
		 FAT size.
01d,20mar90,kdl	 added new driver scheme, DOS 4.0 compatibility, time routine
		 hook, direct I/O for large transfers, file descriptor locking.
01c,20feb90,kdl	 created autoSync and changeNoWarn options to reduce disk I/O,
		 made ready-change internal, added support for contiguous files.
01b,07nov89,kdl  misc. fixes and cleanup
01a,04oct89,kdl  written
*/

/*
INTERNAL: MS-DOS is a registered trademark of Microsoft Corporation.

DESCRIPTION
This library provides services for file-oriented device drivers to use the
MS-DOS\(rg file standard.  This module takes care of all necessary
buffering, directory maintenance, and file system details.

USING THIS LIBRARY
The various routines provided by the VxWorks DOS file system (dosFs) may be
separated into three broad groups: general initialization, device
initialization, and file system operation.

The dosFsInit() routine is the principal initialization function; it need
only be called once, regardless of how many dosFs devices are to be used.  In
addition, dosFsDateTimeInstall() (if used) will typically be called only
once, prior to performing any actual file operations, to install a
user-supplied routine which provides the current date and time.

Other dosFs functions are used for device initialization.  For each dosFs
device, either dosFsDevInit() or dosFsMkfs() must be called to install the
device and define its configuration.  The dosFsConfigInit() routine is
provided to easily initialize the data structure used during device
initialization; however, its use is optional.

Several routines are provided to inform the file system of changes
in the system environment.  The dosFsDateSet() and dosFsTimeSet() routines
are used to set the current date and time; these are normally used only if
no user routine has been installed via dosFsDateTimeInstall().  The
dosFsModeChange() call may be used to modify the readability or
writability of a particular device.  The dosFsReadyChange() routine is
used to inform the file system that a disk may have been swapped, and that
the next disk operation should first remount the disk.  Finally,
dosFsVolUnmount() informs the file system that a particular device should
be synchronized and unmounted, generally in preparation for a disk
change.

More detailed information on all of these routines is discussed in the
following sections.

INITIALIZING DOSFSLIB
Before any other routines in dosFsLib can be used, the routine dosFsInit() must
be called to initialize this library.  This call specifies the
maximum number of dosFs files that can be open simultaneously.
Attempts to open more dosFs files than the specified maximum will result
in errors from open() and creat().

This initialization is enabled when the configuration macro INCLUDE_DOSFS is
defined; dosFsInit() is then called from the root task, usrRoot(),
in usrConfig.c.

DEFINING A DOSFS DEVICE
To use this library for a particular device, the device descriptor
structure used by the device driver must contain, as the very first item,
a block device description structure (BLK_DEV).  This must be initialized
before calling dosFsDevInit().  In the BLK_DEV structure, the driver
includes the addresses of five routines which it must supply:  one that
reads one or more sectors, one that writes one or more sectors, one that
performs I/O control on the device (using ioctl()), one that checks the
status of the device, and one that resets the device.  These routines are
described below.  The BLK_DEV structure also contains fields which
describe the physical configuration of the device.  For more information
about defining block devices, see the 
.I "VxWorks Programmer's Guide: I/O System."

The dosFsDevInit() routine associates a device with the dosFsLib
functions.  It expects three parameters:
.IP "(1)" 4
A pointer to a name string, to be used to identify the device.
This will be part of the pathname for I/O operations which operate on the
device.  This name will appear in the I/O system device table, which may be
displayed using the iosDevShow() routine.
.IP "(2)"
A pointer to the BLK_DEV structure which describes the device and contains the
addresses of the five required functions.  The fields in this structure
must have been initialized before the call to dosFsDevInit().
.IP "(3)"
A pointer to a volume configuration structure (DOS_VOL_CONFIG).  This
structure contains configuration data for the volume which are specific to
the dosFs file system.  (See "Changes in Volume Configuration", below, for more
information.)  The fields in this structure must have been initialized before
the call to dosFsDevInit().  The DOS_VOL_CONFIG structure may be initialized
by using the dosFsConfigInit() routine.
.LP

As an example:
.CS
    dosFsDevInit
	(
	char		*volName,     /@ name to be used for volume   @/
	BLK_DEV		*pBlkDev,     /@ pointer to device descriptor @/
	DOS_VOL_CONFIG	*pVolConfig   /@ pointer to vol config data   @/
	)
.CE