nfsdrv.c

VXWORKS源代码

/* nfsDrv.c - Network File System (NFS) I/O driver */

/* Copyright 1984 - 2001 Wind River Systems, Inc. */
#include "copyright_wrs.h"

/*
modification history
--------------------
03l,07may02,kbw  man page edits
03k,06nov01,vvv  made max. path length configurable (SPR #63551)
03j,15oct01,rae  merge from truestack ver 03s, base 03h (SPR #9357 etc.)
03i,07feb01,spm  merged from version 03o of tor3_x branch (base 03h):
                 fixed group validation in nfsMountAll (SPR #3524),
                 added permission checks to nfsOpen() routine (SPR #21991)
03h,14mar99,jdi  doc: removed refs to config.h and/or configAll.h (SPR 25663).
03g,15dec98,cjtc added helper routine nfsDrvNumGet() to return the nfs
		 driver number in the io system. This is needed by the
		 WindView host to ensure that the upload is going via
		 the upload mechanism requested
03f,20nov97,gnn  fix for spr#5436, need to support FIOFSTATFSGET
03e,26aug97,spm  removed compiler warnings (SPR #7866)
03f,19aug97,cth  changed nfsCacheSize back to before 03e (SPR 7834) fixed by
		 fixing SPR 8460.
03e,15apr97,cth  added simsol specific fix for spr#7834 (for sirocco release), 
           +dvs  at some pt this probably needs to be better integrated.
03d,06aug96,sgv  fix for spr#6468
02s,13feb95,jdi  doc tweaks.
02r,12jan95,rhp  doc: add FIOSYNC to list of NFS ioctl functions. 
		   Also, jdi doc tweaks to nfsDevListGet() and nfsDevInfoGet().
02q,01dec93,jag  added the routines nfsDevListGet(), and nfsDevInfoGet().  
		 These routines provide support for the SNMP demo.
02q,08sep94,jmm  changed NFS client to use new RPC genned xdr routines
02p,28jul93,jmm  added permission checking to nfsOpen () (spr 2046)
02o,01feb93,jdi  documentation cleanup for 5.1; added third param to
		 ioctl() examples.
02n,13nov92,dnw  added include of semLibP.h
02m,21oct92,jdi  removed mangen SECTION designation.
02l,02oct92,srh  added ioctl(FIOGETFL) to return file's open mode
02k,16sep92,jcf  added include of errnoLib.h.
02j,04sep92,jmm  changed nfsUnmount to make sure device names match exactly
                   (spr 1564)
02i,19jul92,smb  added include fcntl.h.
02h,26may92,rrr  the tree shuffle
02g,19Mar92,jmm  changed nfsSeek to allow seeks beyond EOF
                 added #include of pathLib.h
02f,20jan92,jmm  changed nfsOpen to not truncate path names after
                 looking up symlinks
02e,16dec91,gae  added includes plus fixes for ANSI.
02d,04oct91,rrr  passed through the ansification filter
                  -changed functions to ansi style
		  -changed includes to have absolute path from h/
		  -changed READ, WRITE and UPDATE to O_RDONLY O_WRONLY and ...
		  -changed VOID to void
		  -changed copyright notice
02c,05apr91,jdi	 documentation -- removed header parens and x-ref numbers;
		 doc review by dnw.
02b,21feb91,jaa	 documentation cleanup.
02a,08oct90,dnw  changed nfsMountAll verbose flag to quiet flag.
01z,08oct90,hjb  de-linted.
01y,02oct90,hjb  nfsWrite() changed to avoid reading data into cache to
		   keep cache up-to-date when size of data being written
		   is bigger than the nfs cache size.
01x,10aug90,dnw  added verbose arg to nfsMountAll().
01w,26jun90,jcf  changed semaphore types.
		 removed super semaphores.
01v,29may90,dnw  fixed nfsMount to free allocated memory if iosDevAdd returns
		   ERROR
01u,10may90,dnw  added nfsMountAll
		 change nfsClose() to not call nfsClientClose() (unless
		   nfsAutoClose is set TRUE)
		 made SSEMAPHORE include embedded SEM_BINARY which is inited
		   instead of a SEM_ID which is created (to reduce malloc).
		 changed NFS_MAXPATHLEN to (PATH_MAX + 1)
01t,01may90,llk  added FIOREADDIR and FIOFSTATGET ioctl calls.
		 deleted FIODIRENTRY ioctl call.
01s,01apr90,llk  changed nfsRead() to always return the number of bytes
		   requested by caller (up to the bytes left in the file).
		 changed name nfsFlushCache() to nfsCacheFlush().
		 added "DEFICIENCIES" documentation (and probably some
		   deficiencies).
		 made string arrays shorter than defined in the NFS spec.
		 fixed bug which didn't update file ptr correctly if cache
		   size was 0.
		 coalesced malloc of cache and fd into one malloc.
01r,14mar90,jdi  documentation cleanup.
01q,09aug89,dab  made nfsOpen() check for O_TRUNC flag.
                 made nfsCreate() truncate file if file already exists.
01p,12jul89,llk  lint.
01o,24mar89,dab  caching disabled when nfsCacheSize is zero;
           +gae  formerly a bug when nfsCacheSize was zero.
01n,23mar89,dab  added FIOSYNC option to nfsIoctl().
01m,21nov88,jcf  lint.
01l,19oct88,llk  documentation.
01k,28sep88,llk  documentation.
01j,24aug88,gae  documentation.  Made nfsMount() check hostname, and
		 allow default local name.
01i,07jul88,jcf  lint.
01h,30jun88,llk  changed to handle links.
		 added nfsDevShow().
01g,22jun88,dnw  changed taskIdGet() to taskIdSelf().
01f,16jun88,llk  changed to more v4 names.
01e,04jun88,llk  added rm, mkdir, rmdir.
		 changed how nfsOpen retrieves directory and file names.
01d,30may88,dnw  changed to v4 names.
01c,04may88,jcf  changed ssemaphores to be consistent with new semLib.
01b,22apr88,gae  fixed drvnum reference in nfsUnmount().
01a,19apr88,llk  written.
*/

/*
This driver provides facilities for accessing files transparently over the
network via NFS (Network File System).  By creating a network device
with nfsMount(), files on a remote NFS system (such as a UNIX system) can
be handled as if they were local.

USER-CALLABLE ROUTINES
The nfsDrv() routine initializes the driver.  The nfsMount() and nfsUnmount()
routines mount and unmount file systems.  The nfsMountAll() routine mounts
all file systems exported by a specified host.

INITIALIZATION
Before using the network driver, it must be initialized by calling nfsDrv().
This routine must be called before any reads, writes, or other NFS calls.
This is done automatically when INCLUDE_NFS is defined..

CREATING NFS DEVICES
In order to access a remote file system, an NFS device must be created by
calling nfsMount().  For example, to create the device `/myd0/' for the file
system `/d0/' on the host `wrs', call:
.CS
    nfsMount ("wrs", "/d0/", "/myd0/");
.CE
The file `/d0/dog' on the host `wrs' can now be accessed as `/myd0/dog'.

If the third parameter to nfsMount() is NULL, VxWorks creates a device with
the same name as the file system.  For example, the call:
.CS
    nfsMount ("wrs", "/d0/", NULL);
.CE
or from the shell:
.CS
    nfsMount "wrs", "/d0/"
.CE
creates the device `/d0/'.  The file `/d0/dog' is accessed by the same name,
`/d0/dog'.

Before mounting a file system, the host must already have been created
with hostAdd().  The routine nfsDevShow() displays the mounted NFS devices.

IOCTL FUNCTIONS
The NFS driver responds to the following ioctl() functions:
.iP "FIOGETNAME" 18 3
Gets the file name of <fd> and copies it to the buffer referenced 
by <nameBuf>:
.CS
    status = ioctl (fd, FIOGETNAME, &nameBuf);
.CE
.iP "FIONREAD"
Copies to <nBytesUnread> the number of bytes remaining in the file
specified by <fd>:
.CS
    status = ioctl (fd, FIONREAD, &nBytesUnread);
.CE
.iP "FIOSEEK"
Sets the current byte offset in the file to the position specified by
<newOffset>.  If the seek goes beyond the end-of-file, the file grows.
The end-of-file pointer gets moved to the new position, and the new space
is filled with zeros:
.CS
    status = ioctl (fd, FIOSEEK, newOffset);
.CE
.iP "FIOSYNC"
Flush data to the remote NFS file.  It takes no additional argument:
.CS
    status = ioctl (fd, FIOSYNC, 0);
.CE
.iP "FIOWHERE"
Returns the current byte position in the file.  This is the byte offset of
the next byte to be read or written.  It takes no additional argument:
.CS
    position = ioctl (fd, FIOWHERE, 0);
.CE
.iP "FIOREADDIR"
Reads the next directory entry.  The argument <dirStruct> is a pointer to
a directory descriptor of type DIR.  Normally, the readdir() routine is used to
read a directory, rather than using the FIOREADDIR function directly.  See
the manual entry for dirLib:
.CS
    DIR dirStruct;
    fd = open ("directory", O_RDONLY);
    status = ioctl (fd, FIOREADDIR, &dirStruct);
.CE
.iP "FIOFSTATGET"
Gets file status information (directory entry data).  The argument
<statStruct> is a pointer to a stat structure that is filled with data
describing the specified file.  Normally, the stat() or fstat() routine is
used to obtain file information, rather than using the FIOFSTATGET
function directly.  See the manual entry for dirLib:
.CS
    struct stat statStruct;
    fd = open ("file", O_RDONLY);
    status = ioctl (fd, FIOFSTATGET, &statStruct);
.CE

.iP "FIOFSTATFSGET"
Gets the file system parameters for and open file descriptor.  The argument
<statfsStruct> is a pointer to a statfs structure that is filled with data
describing the underlying filesystem.  Normally, the stat() or fstat() routine
is used to obtain file information, rather than using the FIOFSTATGET function
directly.  See the manual entry for dirLib:

.CS
    statfs statfsStruct;
    fd = open ("directory", O_RDONLY);
    status = ioctl (fd, FIOFSTATFSGET, &statfsStruct);
.CE

DEFICIENCIES
There is only one client handle/cache per task.
Performance is poor if a task is accessing two or more NFS files.

Changing <nfsCacheSize> after a file is open could cause adverse effects.
However, changing it before opening any NFS file descriptors should not
pose a problem.

INCLUDE FILES: nfsDrv.h, ioLib.h, dirent.h

SEE ALSO: dirLib, nfsLib, hostAdd(), ioctl(),
*/

#include "vxWorks.h"
#include "iosLib.h"
#include "ioLib.h"
#include "memLib.h"
#include "stdlib.h"
#include "semLib.h"
#include "string.h"
#include "lstLib.h"
#include "rpc/rpc.h"
#include "xdr_nfs.h"
#include "xdr_nfsserv.h"
#include "hostLib.h"
#include "sys/stat.h"
#include "dirent.h"
#include "errnoLib.h"
#include "errno.h"
#include "stdio.h"
#include "nfsLib.h"
#include "nfsDrv.h"
#include "pathLib.h"
#include "fcntl.h"
#include "memPartLib.h"
#include "private/semLibP.h"

IMPORT unsigned int nfsMaxMsgLen;	/* max. length of NFs read/write buf */
IMPORT int          nfsMaxPath;         /* max. length of file path */

/* XXX FD_MODE is defined in here and in netDrv */

#define FD_MODE		3	/* mode mask for opened file */
				/* O_RDONLY, O_WRONLY or O_RDWR */
#ifdef __GNUC__
# ifndef alloca
#  define alloca __builtin_alloca
# endif
#endif

typedef struct			/* NFS_DEV - nfs device structure */
    {
    DEV_HDR	devHdr;			  /* nfs device header */
    char	host[MAXHOSTNAMELEN];	  /* host for this device */
    nfs_fh	fileHandle;		  /* handle for mounted file system */

    /*
     * File system mounted on this dev - though it appears as a single 
     * character, it is really a character array - the memory for the array
     * is allocated when an NFS_DEV struct is allocated. This change was 
     * required for configurable file path length support.
     */

    char	fileSystem[1];            
    } NFS_DEV;

/* nfs file descriptor */

typedef struct			/* NFS_FD - NFS file descriptor */
    {
    NFS_DEV	*nfsDev;		/* pointer to this file's NFS device */
    nfs_fh	 fileHandle;		/* file's file handle */
    nfs_fh	 dirHandle;		/* file's directory file handle */
    fattr	 fileAttr;		/* file's attributes */
    unsigned int mode;			/* (O_RDONLY, O_WRONLY, O_RDWR) */
    unsigned int fileCurByte;		/* number of current byte in file */
    SEM_ID	 nfsFdSem;		/* accessing semaphore */
    BOOL	 cacheValid;		/* TRUE: cache valid and remaining */
					/* fields in structure are valid. */
					/* FALSE: cache is empty or */
					/* cacheCurByte not the same as the */
					/* current byte in the file. */
    char	*cacheBuf;		/* pointer to file's read cache */
    char 	*cacheCurByte;		/* pointer to current byte in cache */
    unsigned int cacheBytesLeft;	/* number of bytes left in cache */
					/* between cacheCurByte and the end */
					/* of valid cache material.  NOTE: */
					/* This number may be smaller than */
					/* the amount of room left in for */
					/* the cache writing. */
    BOOL	 cacheDirty;		/* TRUE: cache is dirty, not flushed */
    } NFS_FD;

/* globals */

int mutexOptionsNfsDrv = SEM_Q_PRIORITY | SEM_DELETE_SAFE | SEM_INVERSION_SAFE;

unsigned int nfsCacheSize;		/* size of an nfs cache */
BOOL	 nfsAutoClose;			/* TRUE: close client after file close*/

/* locals */

LOCAL int nfsDrvNum;			/* this particular driver number */

/* forward declarations */

LOCAL int nfsCacheFlush ();
LOCAL STATUS nfsClose ();
LOCAL int nfsCreate ();
LOCAL int nfsDelete ();
LOCAL int nfsIoctl ();
LOCAL int nfsOpen ();
LOCAL int nfsRead ();
LOCAL int nfsSeek  ();
LOCAL int nfsWrite ();
LOCAL int nfsChkFilePerms ();

/*******************************************************************************
*
* nfsDrv - install the NFS driver
*
* This routine initializes and installs the NFS driver.  It must be 
* called before any reads, writes, or other NFS calls.
* This is done automatically when INCLUDE_NFS is defined.
*
* VXWORKS AE PROTECTION DOMAINS
* Under VxWorks AE, you can call this function from within the kernel 
* protection domain only.  This restriction does not apply under non-AE 
* versions of VxWorks.  
*
* RETURNS:
* OK, or ERROR if there is no room for the driver.
*/

STATUS nfsDrv (void)
    {
    if (nfsDrvNum == 0)
	{
	nfsCacheSize = nfsMaxMsgLen;

	nfsDrvNum = iosDrvInstall (nfsCreate, nfsDelete, nfsOpen, nfsClose,
				   nfsRead, nfsWrite, nfsIoctl);
	}

    return (nfsDrvNum == ERROR ? ERROR : OK);
    }
/*******************************************************************************
*
* nfsDrvNumGet - return the IO system driver number for the nfs driver
*
* This routine returns the nfs driver number allocated by iosDrvInstall during
* the nfs driver initialization. If the nfs driver has yet to be initialized,
* or if initialization failed, nfsDrvNumGet will return ERROR.
*
* RETURNS: the nfs driver number or ERROR
*/

int nfsDrvNumGet (void)
    {
    return (nfsDrvNum == 0 ? ERROR : nfsDrvNum);
    }

/*******************************************************************************
*
* nfsMount - mount an NFS file system
*
* This routine mounts a remote file system.  It creates a
* local device <localName> for a remote file system on a specified host.
* The host must have already been added to the local host table with
* hostAdd().  If <localName> is NULL, the local name will be the same as
* the remote name.
*
* RETURNS: OK, or ERROR if the driver is not installed,
* <host> is invalid, or memory is insufficient.
*
* SEE ALSO: nfsUnmount(), hostAdd()
*/

STATUS nfsMount
    (
    char *host,         /* name of remote host */
    char *fileSystem,   /* name of remote directory to mount */
    char *localName     /* local device name for remote dir */
                        /* (NULL = use fileSystem name) */
    )
    {
    FAST NFS_DEV *pNfsDev;
    nfs_fh fileHandle;

    if (nfsDrvNum < 1)
	{
	errnoSet (S_ioLib_NO_DRIVER);
	return (ERROR);
	}

    if (strlen (fileSystem) >= nfsMaxPath)
	{
	errnoSet (S_nfsLib_NFSERR_NAMETOOLONG);
	return (ERROR);
	}