TweetFollow Us on Twitter

AShare UserName
Volume Number:7
Issue Number:6
Column Tag:Programmer's Forum

AppleShare Username to Chooser Name INIT

By Mark Gavin, Darby, PA

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

[ Mark Gavin is a consultant in the Philadelphia area who specializes in Macintosh software development using MacApp, Object Pascal and 68000 Assembly. He can be reached via AppleLink GAVIN.MARK. ]

INIT’s in General

It used to be that an INIT had to be loaded into the system file using ResEdit or some other resource installer. Only 32 INIT’s were allowed in the system file and you had to be aware of possible resource ID conflicts during the installation process. A while back Apple enhanced the INIT system by placing INIT 31 within the system file. The job of INIT 31 is to look in the system folder for any files of type ‘INIT’ who happen to have one or more ‘INIT’ resources. The search is in alphabetical order by filename. When INIT 31 locates an INIT resource it is called and executed as if it were a procedure (Inside Macintosh Volume IV, pp. 255-257) . INIT 31 can also allocate memory in the system heap for the INIT if you use the ‘sysz’ resource (Inside Macintosh Volume V, pg. 352). As is, INIT 31 gives you at least a 16K block within the system heap.

An INIT in it’s basic form is a stand alone code module which normally has no access to global data or anything that uses A5 relative addressing like QuickDraw. This minor inconvenience can be easily circumvented by creating your own A5 world. There is a very good explanation, and examples, of setting up your own A5 world in Apple’s Macintosh Technical Note #256, Stand-Alone Code, ad nauseam.

Network Administration and Responder

One of my clients has implemented a wide area EtherNet network which covers 15 sites with 76 zones and 56 networks throughout the United States. Network support is via Timbuktu which uses the Chooser name to identify each Mac. They also use Inter•Poll and NetMinder for network diagnostics. These, also, use the Chooser name, broadcast by the Responder.

Responder is an INIT supplied by Apple on the Macintosh System software disks. Its function is to register the Macintosh Chooser name on the AppleShare network. The Responder and the other utilities described above, play an important role in network administration by allowing us to easily locate an individual Macintosh and it’s owner on the network. The Chooser name, however, can be easily modified or deleted by the user. For example, the network administrator, located in Pennsylvania, would have trouble determining who owns a Macintosh named ‘Wizard’ located in California or Connecticut. In addition, there is no guarantee the Macintosh will have the same name tomorrow or the next day.

Placing the AppleShare username into the Chooser name appears to be the most straight forward solution to the problem of system identification and offers us several advantages:

1. Avoid burdening the user with yet one more administrative task.

2. Automatic update of Chooser name with new user.

3. The Chooser name can not be permanently modified by the user.

The AShareNameINIT

The function of the AShareNameINIT is to extract the AppleShare username from the ‘AppleShare Prep’ file and place the username in the Chooser. I have chosen not to display an ICON at startup because this INIT is a network administration tool that should not be disabled by the user. Therefore, the less obtrusive the better.

The AppleShare Prep File

Apple hasn’t released any information on the AppleShare Prep file, so this is what I have figured out thus far.

The AppleShare Prep file is created by selecting the AppleShare device within the Chooser. When the file is created it contains 4 bytes, all nil, within a single resource ‘BMLS’ 2447. The AppleShare logon name is only placed into the BMLS resource if the user chooses to have an AppleShare volume auto-logon at startup. As a side note; If you elect to have AppleShare automatically logon to a server with your name and password, the password is also placed in the AppleShare Prep file but it is not encrypted in any way. By looking at the resource with ResEdit you can read any stored password.

The AppleShare Prep file saves a username and server history when the server name changes. There does not appear to be any way of deleting information that is no longer being used by AppleShare. This history is stored in a linked list of entries. The number of entries in the file is stored in the first word of the BMLS resource. The second word of the resource contains the size of the block to follow. It is also used as an offset to the next entry in the list. Logical block size within the resource is variable according to how many server disks are mounted. The username is a 32 byte Pascal string located 20 bytes after the blocksize. Currently, the INIT uses the last name in the list of AppleShare usernames located within the BMLS resource.

The Chooser Name

The Chooser Name is located in a ‘STR ‘ resource within the System file whose ID is -16096. This is a Pascal string which is exactly 32 bytes. Any more or less may cause problems because all of the applications that use the Chooser name expect 32 bytes. Even-thought it is technically a STR resource, it would not be wise to try to fill it with a Str255.

The Code

The TYPE intPtr is used to coerce the Mac into returning a word instead of a byte as it would normally.

There is bug in the 128K and later versions of the ROM which will cause _OpenRFPerm not to pass trap discipline under TMON. When you hard code a string into the code resource, like I am doing with the ‘AppleShare Prep’ filename, _OpenRFPerm calls _RecoverHandle with a bad Master Pointer. This is the reason for calling StripAddress on the address of the filename. For a more complete explanation please refer to Technical Note #232 Strip with _OpenResFile and _OpenRFPerm.

The ENTRYPOINT Procedure and the forward declaration of the AShareNameINIT procedure are needed because of the CloseAndExit nested procedure. If the forward declaration is not used the CloseAndExit procedure will be the first procedure executed within the INIT code segment and cause all kinds of nasty things to happen; i.e., trample on the stack.

The CloseAndExit procedure could have been avoided just by using a GOTO to jump to the CloseResFile statement at the end of the procedure. However, I think the nested procedure results in cleaner looking code even-though using a GOTO is a more efficient solution in this particular case.

I like to place the About information and the compilation date directly into the executable code. MPW Pascal, however, is an optimizing compiler which will strip out all string constants or code that are not referenced. The IF statement containing the deadStrip boolean is a quick and dirty way of bypassing the MPW Pascal compiler optimization and forcing an About string and the compilation date into the executable code segment. The deadStrip boolean is needed because simply setting the IF statement to false will cause the entire IF statement to be striped from the code.

When the user sets AppleShare to autologon to a server as a Guest, the AppleShare Prep file contains a null string. If this is the case, we do not want to copy a null string into the Chooser because Responder will ask the user to name the Macintosh after each restart. This would be rather annoying to the user.

Program Flow

1. Get the vRefNum of the startup volume.

2. Open the resource fork of the AppleShare Prep file.

3. Get a handle to BMLS 2447.

4. Get a handle to STR -16096.

5. Check for data in BMLS 2447.

6. How many entries are in the linked list.

7. Offset to the last entry in the linked list.

8. Check for a nil name.

9. Copy the name to STR -16096.

10. Cleanup.

That’s all there is to it. INIT’s, in general, are relatively straight forward to write. Just be careful and test using heap scramble, purge and trap discipline.

Bibliography

Macintosh Technical Notes:

#129 _SysEnvirons: System 6.0 and Beyond.

#232 Strip with _OpenResFile and _OpenRFPerm.

#247 Giving the (Desk)Hook to INIT’s.

#256 Stand-Alone Code, ad nauseam.

Listing: ASharINIT.p

{ --------------------------
  AShareNameINIT
  
 Type   INIT
 ID16056
 Version1.5
 Wednesday, December 5, 1990 9:53:37 AM
 ©1990 by Mark Gavin
 All Rights Reserved
-------------------------- }
{$Z+} { Identify all routines to the Linker as
 external.  If this is not used then
 ENTRYPOINT must be placed in the
 INTERFACE section }
    
  UNIT _AShareNameINIT;

INTERFACE
 USES
 Types, Memory, ToolUtils,
 OSUtils, Resources, PaslibIntf, Packages;

 TYPE
 intPtr = ^integer;
 {used to retrieve an integer from the resource}
 

{$R-}   { Turn Off Range Checking }
{$OV-}  { Ignore Arithmetic Overflows }

IMPLEMENTATION

 PROCEDURE AShareNameINIT;FORWARD;


 PROCEDURE ENTRYPOINT;

 BEGIN
 AShareNameINIT;
 END;

{ ---------------------------------- }
  PROCEDURE AShareNameINIT;
 
    VAR
 str    : Str255;
 
 volNamePtr : StringPtr;
 
 theStringPtr,
 theNamePtr : Ptr;
 
 { AppleShare Prep resHdl }
 ASPResHandle,
 chooserStringHdl: Handle;
 
 ASPHandleSize   : longint;
 
 index,
 blocksize,
 resOffset,
 offsetMultiplier,
 stringLength,
 refNum,
 vRefNum,
 oldResFileRef   : integer;
 
 anError: OSErr;
 
 deadStrip: Boolean;

 { ------------------------------------ }
 PROCEDURE CloseAndExit;
 
 BEGIN  
 CloseResFile(refNum);
 UseResFile(oldResFileRef);
 EXIT(AShareNameINIT);    
 END;
 
 { ------------------------------------ }
 BEGIN  
 oldResFileRef := CurResFile;
 
 deadStrip := False;
 IF deadStrip THEN BEGIN
 str := ‘AShareNameINIT 1.5 by Mark Gavin’;
 str := compdate;
 END;

 { GetVol returns the name of the
 default volume in volNamePtr and
 its volume reference number in vRefNum. }
 
 volNamePtr := StringPtr(NewPtr(256));
 IF MemError <> noErr THEN
 EXIT(AShareNameINIT);

 anError := GetVol(volNamePtr, vRefNum);
 IF anError <> noErr THEN
 EXIT(AShareNameINIT);

 DisposPtr(Ptr(volNamePtr));
 { Ptr only needed for GetVol }

 str := ‘AppleShare Prep’;
 { StripAddress used per Tech Note 232
 - bug in OpenRFPerm }
 refNum := OpenRFPerm(StringPtr(StripAddress(@str))^, vRefNum, fsRdPerm);
 IF ResError <> noErr THEN
 EXIT(AShareNameINIT);  
 
 ASPResHandle := GetResource(‘BMLS’, 2447);
 IF ResError <> noErr THEN
 CloseAndExit; 
 HNoPurge(ASPResHandle);
 
 chooserStringHdl := GetResource(‘STR ‘, -16096);
 IF ResError <> noErr THEN
 CloseAndExit; 
 HNoPurge(chooserStringHdl);
 
 ASPHandleSize := GetHandleSize(ASPResHandle);
 IF MemError <> noErr THEN
 CloseAndExit;
 
 { Make sure there is data in the handle }
 IF ASPHandleSize < 55 THEN
 CloseAndExit; 
 
 offsetMultiplier := intPtr(ASPResHandle^)^;
 IF offsetMultiplier < 1 THEN
 CloseAndExit; 

 blockSize := intPtr(ORD4(ASPResHandle^) + 2)^;
 IF blockSize < 1 THEN
 CloseAndExit; 
 
 resOffset := 2;
 
 FOR index := 1 TO (offsetMultiplier - 1) DO
 BEGIN
 resOffset := resOffset + blockSize;
 blockSize := intPtr(ORD4(ASPResHandle^) + resOffset)^;
 IF blockSize < 1 THEN
 CloseAndExit;
 END;

 resOffset :=  resOffset + 20;
 { offset to string within block }

 theNamePtr := Ptr(ORD4(ASPResHandle^) + resOffset);
 
 IF theNamePtr^ = 0 THEN
 CloseAndExit;{ exit on nil name }
 
 theStringPtr := chooserStringHdl^;

 BlockMove(theNamePtr, theStringPtr, 32);
 
 ChangedResource(chooserStringHdl);
 WriteResource(chooserStringHdl);

 HPurge(chooserStringHdl);
 HPurge(ASPResHandle);
 
 CloseResFile(refNum);
 
 UseResFile(oldResFileRef);

   END;
 END.
Listing:  AShareINIT.make

{ -------------------------- }
#   File:       AShareNameINIT.make
#   Target:     AShareNameINIT
#   Sources:    AShareNameINIT.p
#   Created:    Monday, November 26, 1990 4:39:50 PM
#©1990 by Mark Gavin

AShareNameINIT.p.o ƒ AShareNameINIT.make AShareNameINIT.p
  Pascal  AShareNameINIT.p

SOURCES = AShareNameINIT.p
OBJECTS = AShareNameINIT.p.o

AShareNameINIT ƒƒ AShareNameINIT.make AShareNameINIT.p.o
 Link -t INIT -c ‘ASN?’ -rt INIT=16056 -ra =resLocked -sg AShareNameINIT 
-m ENTRYPOINT 
 {OBJECTS} 
 “{Libraries}”Interface.o 
 -o AShareNameINIT

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Yasu 3.0.3 - System maintenance app; per...
Yasu was created with System Administrators who service large groups of workstations in mind, Yasu (Yet Another System Utility) was made to do a specific group of maintenance tasks quickly within a... Read more
MYStuff Pro 2.0.26 - $39.99
MYStuff Pro is the most flexible way to create detail-rich inventories for your home or small business. Add items to MYStuff by dragging and dropping existing information, uploading new images, or... Read more
MarsEdit 3.7.8 - Quick and convenient bl...
MarsEdit is a blog editor for OS X that makes editing your blog like writing email, with spell-checking, drafts, multiple windows, and even AppleScript support. It works with with most blog services... Read more
Apple iBooks Author 2.5 - Create and pub...
Apple iBooks Author helps you create and publish amazing Multi-Touch books for iPad. Now anyone can create stunning iBooks textbooks, cookbooks, history books, picture books, and more for iPad. All... Read more
TunnelBear 3.0.1 - Subscription-based pr...
TunnelBear is a subscription-based virtual private network (VPN) service and companion app, enabling you to browse the internet privately and securely. Features Browse privately - Secure your data... Read more
ExpanDrive 5.4.0 - Access cloud storage...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more
Opera 40.0.2308.62 - High-performance We...
Opera is a fast and secure browser trusted by millions of users. With the intuitive interface, Speed Dial and visual bookmarks for organizing favorite sites, news feature with fresh, relevant content... Read more
Apple iOS 10.0.2 - The latest version of...
iOS 10 is the biggest release of iOS ever. A massive update to Messages brings the power of the App Store to your conversations and makes messaging more personal than ever. Find your route with... Read more
Herald 7.0 - Notification plugin for Mai...
Note: Versions 2.1.3 (for OS X 10.7), 3.0.6 (for OS X 10.8), 4.0.8 (for OS X 10.9), 5.0.2 (for OS X 10.10), and 6.0.3 (for OS X 10.11) are no longer supported by the developer. Herald is a... Read more
Postbox 5.0.2 - Powerful and flexible em...
Postbox is a new email application that helps you organize your work life and get stuff done. It has all the elegance and simplicity of Apple Mail, but with more power and flexibility to manage even... Read more

How to build and care for your team in D...
Before you hit the trail and become a dog sledding legend, there’s actually a fair bit of prep work to be done. In Dog Sled Saga, you’re not only racing, you’re also building and caring for a team of furry friends. There’s a lot to consider—... | Read more »
How to win every race in Dog Sled Saga
If I had to guess, I’d say Dog Sled Saga is the most adorable racing game on the App Store right now. It’s a dog sled racing sim full of adorable, loyal puppies. Just look at those fluffy little tails wagging. Behind that cute, pixelated facade is... | Read more »
Let the war games commence in Gunship Ba...
Buzz Lightyear famously said, “This isn’t flying, this is falling – with style!” In the case of Gunship Battle: Second War, though, this really is flying - with style! The flight simulator app from Joycity puts you in control of 20 faithfully... | Read more »
How to get a high score in Fired Up
Fired Up is Noodlecake Games’ high score chasing, firefighting adventure. You take control of a wayward firefighter who propels himself up the side of a highrise with blasts of water. Sound silly? It is. It’s also pretty difficult. You can’t... | Read more »
NBA 2K17 (Games)
NBA 2K17 1.0 Device: iOS iPhone Category: Games Price: $7.99, Version: 1.0 (iTunes) Description: Following the record-breaking launch of NBA 2K16, the NBA 2K franchise continues to stake its claim as the most authentic sports video... | Read more »
Dog Sled Saga (Games)
Dog Sled Saga 1.0.1 Device: iOS Universal Category: Games Price: $3.99, Version: 1.0.1 (iTunes) Description: A game by Dan + Lisa As a rookie musher, foster a dogsledding team whose skills will grow if they're treated right. Week by... | Read more »
60 Seconds! Atomic Adventure (Games)
60 Seconds! Atomic Adventure 1.2 Device: iOS Universal Category: Games Price: $2.99, Version: 1.2 (iTunes) Description: 60 Seconds! is a dark comedy atomic adventure of scavenge and survival. Collect supplies and rescue your family... | Read more »
Tons of Bullets! (Games)
Tons of Bullets! 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Tons of BulletsA retro 2D pixel platformer infused with tons of bullets and tons of features!Fight as Kenji the Ninja and... | Read more »
Sorcery! 4 (Games)
Sorcery! 4 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: *** PLEASE NOTE: Sorcery! 4 requires a minimum of iPad 3 or iPhone 4 *** An epic adventure through a cursed citadel of monsters,... | Read more »
Building the perfect Animation Throwdown...
Animation Throwdown is a casual card game full of plenty of inside jokes from some of your favorite cartoons. It’s accessible as far as card games go, but that’s not to say that it hands your victories to you easily. There’s quite a bit that goes... | Read more »

Price Scanner via MacPrices.net

Duplicate Sweeper Free On Mac App Store For O...
To celebrate the launch of Apple’s latest macOS Sierra, Stafford, United Kingdom based Wide Angle Software has announced that its duplicate file finder software, Duplicate Sweeper, is now available... Read more
13-inch Retina MacBook Pros on sale for up to...
B&H Photo has 13″ Retina Apple MacBook Pros on sale for up to $150 off MSRP. Shipping is free, and B&H charges NY tax only: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1174.99 $125 off MSRP - 13... Read more
Evidence Surfaces Pointing To New A10X Chip F...
Citing a job description for a Project Lead position at Apple’s Austin, Texas engineering labs, Motley Fool’s Ashraf Eassa deduces that development is progressing well on Apple’s next-generation in-... Read more
Check Print’R for macOS Allows Anyone to Easi...
Delaware-based Match Software has announced the release and immediate availability of Check Print’R 3.21, an important update to their easy-to-use check printing application for macOS. Check Print’R... Read more
Apple refurbished 11-inch MacBook Airs availa...
Apple has Certified Refurbished 11″ MacBook Airs (the latest models), available for up to $170 off the cost of new models. An Apple one-year warranty is included with each MacBook, and shipping is... Read more
Apple refurbished 15-inch Retina MacBook Pros...
Apple has Certified Refurbished 2015 15″ Retina MacBook Pros available for up to $380 off the cost of new models. An Apple one-year warranty is included with each model, and shipping is free: - 15″ 2... Read more
Major Version 5 Release Of Free myTuner Radio...
AppGeneration Software has announced the release of myTuner Radio 5.0.1, an important update to their live radio app for iOS and Android platforms. With myTuner Radio, you can listen to more than 30,... Read more
TheAppStore Searches And Filters iOS And macO...
Boston based InchWest has announced the official launch of TheAppStore, a free web based service that lets users search iOS and Mac apps on the web without iTunes or the App store. TheAppStore... Read more
2TB Time Capsule on sale for $199, save $100
Amazon has 2TB Apple Time Capsules on sale for $199 including free shipping. Their price is $100 off MSRP. Choose Amazon as the seller when making your purchase, rather than a third party seller. Read more
12-inch 1.2GHz Rose Gold Retina MacBook on sa...
Amazon.com has the 2016 12″ 1.2GHz Rose Gold Retina MacBook on sale for $1254.02 including free shipping. Their price is $345 off MSRP, and it’s the lowest price available for this model from any... Read more

Jobs Board

*Apple* Retail - Multiple Positions- Manhatt...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
Sr. *Apple* Mac Engineer - Net2Source Inc....
…staffing, training and technology. We have following position open with our client. Sr. Apple Mac Engineer6+ Months CTH Start date : 19th Sept Travelling Job If Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
US- *Apple* Store Leader Program - Apple (Un...
…Summary Learn and grow as you explore the art of leadership at the Apple Store. You'll master our retail business inside and out through training, hands-on Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.