TweetFollow Us on Twitter

Self-Installing Applications

Volume Number: 19 (2003)
Issue Number: 8
Column Tag: Programming

Self-Installing Applications

Or "How I became Installer Free"

by Kenneth H. Wieschhoff, Jr.

Introduction

The last step in any software development process is to create an installer. This can be Apple's PackageMaker, InstallerVise by MindVision, and the like. By making your application self-installing you can update your frameworks, libraries, (and even kernel extensions) dynamically prior to running your main application. Your users can run your application anywhere and you can include incremental updates to your software. This makes a more enjoyable user experience.

The Secret

In short.... Bundles! To the user your application looks like a single item, but in reality it can be an entire suite of tools. You create an Installer application that checks your support files (frameworks, kexts, libraries, et. al.) are present and up to date. Missing/outdated items are installed using Apple's Authorization Services API. Finally, this Installer launches the main application and quits. You store all the items, including the main application, in the Resources Folder within the Installer application.

The Steps

Here's a checklist of thing to do:

Create the self-installer application. Add your main application's icon.

Write code in main to verify your support items are installed and up to date, and then launch the main application.

Create the scripts which will install a given support item. Authorization Services will run these scripts for you at a privileged level.

Create "move" scripts to assist the build process, which move your support files and main application from their respective build directories into the Resources folder within the Installer.

Create the Self-Installer application

When I'm developing a software product that contains many different parts, I usually create a folder to hold all the pieces. In addition to making source control easier to manage, it will simplify creating the "move" scripts. More on that later.

Here's an example of a folder layout for MyApp:

MyApplication
MyApp (the main (real) application)
MyFramework
MySelfInstaller (also produces an application called MyApp)

You'll use Project Builder to create a new "Cocoa Application" in your (new) MySelfInstaller directory. Let's have a look at the main code:

Listing 1: main.m

main.m
Check if support items exist and are up-to-date and then launch the main application.
#import <Cocoa/Cocoa.h>
#include <Security/Authorization.h>
#include <Security/AuthorizationTags.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/param.h>
bool            CheckItemUpToDate(char *where, char *what);
OSStatus      DoInstall(char *script);
void            LaunchMainApplication();
AuthorizationRef gAuthorizationRef = 0;
int main(int argc, const char *argv[])
{
   NSAutoreleasePool *pool=[[NSAutoreleasePool alloc] init];
   OSStatus    stat = noErr;
   if ( !CheckItemUpToDate("/Library/Frameworks/",
             "MyFramework.framework"))
      stat = DoInstall("InstallFramework.sh");
   if ( stat == noErr)
      LaunchMainApplication();
  
   // Release the authorization reference    
   if(gAuthorizationRef)
      AuthorizationFree(gAuthorizationRef,
                         kAuthorizationFlagDefaults);
   [pool release];
   
   return (EXIT_SUCCESS);
}

Main checks that the framework is installed on the user's system and installs it if it's out of date or missing. It then launches the main application and then quits. (Noticeably absent in this example is some way to alert the user that installation of an item failed.)

Listing 2: main.m

main.m
The CheckItemUpToDate checks to see if a given support item is up to date.
bool CheckItemUpToDate(char *where, char *what){
   // Guilty until proven innocent.
   bool         installNotNeeded = false;
   // Create the path to the installed support item.
   NSString      *fullPath = 
         [NSString stringWithFormat:@"%s%s", where, what];
   // Get the url of the "SupportItems" folder
   // within the Resources folder of our application
   CFURLRef      url =
          CFBundleCopyResourceURL(CFBundleGetMainBundle(),
             CFSTR("SupportItems"), NULL, NULL);
   // Get the path to the support item within 
   // our own Resources bundle
   NSString      *supportPath = 
         [NSString stringWithFormat:@"%@%s", 
            [((NSURL *)url) path], what];
   // Get the bundle of the installed support item
   NSBundle      *instExt = [NSBundle bundleWithPath:fullpath];
   // If the extension exists...
   if (instExt) {
      //...load it's dictionary.
      NSDictionary *installedDict = [instExt infoDictionary];
    
      // If the dictionary exists...
      if (installedDict) {
         // Get the short version string
         NSString *version = [installedDict
                objectForKey:@"CFBundleShortVersionString"];
         if (version){
            // Do the entire thing again for the support tool
            NSBundle *local = 
               [NSBundle bundleWithPath:toolpath];
                
            if ( local) {
               NSDictionary *locDict = [local infoDictionary];
                    
               if (locDict) {
                  NSString * locVers = [locDict objectForKey:
                                  @"CFBundleShortVersionString"];
             // Compare the two strings for a match.
                  if ([locVers compare:version] ==NSOrderedSame)
                     installNotNeeded = true;
            }
         }
      }
   }
}
   return installNotNeeded;
}

CheckItemUpToDate compares the Short Version Strings of the installed item against the item packaged in the bundle. Updating the version string causes the item to be re-installed. Up to date items are not re-installed.

The MAGIC

The Authorization Services API provides a way to execute a script that needs privileges.

Listing 3: main.m

main.m
DoInstall gets authorization from the user to execute a script at a privileged level and executes 
the script.

OSStatus DoInstall(char *scriptName)
{
   char myToolPath[MAXPATHLEN];
   char *myArguments[2] = {NULL, NULL};
   FILE *myPipe = NULL;
   char myReadBuffer[128];
   AuthorizationFlags myFlags = kAuthorizationFlagDefaults;
   AuthorizationItem myItems[] = { 
      // For this example we're using the standard 
      // command interpreter 
{kAuthorizationRightExecute, 
      strlen("/bin/sh"), "/bin/sh", 0}};
AuthorizationRights myRights = {
      sizeof(myItems)/sizeof(AuthorizationItem), myItems };
   OSStatus myStatus; 
    
   // Tell the developer what script is being run
   printf("Running install script %s\n", scriptName);
      
   // Store the authorization in a global so we don't keep
   // asking the user for it once it's given.
  if ( gAuthorizationRef == 0) {
      // Create the authorization reference.
      myStatus = AuthorizationCreate
                     (   NULL, 
                        kAuthorizationEmptyEnvironment,
                         myFlags, 
                        &gAuthorizationRef);
      if(myStatus != errAuthorizationSuccess) goto bail;
        
      // Set flags to create our authorization environment.
      // Request to be pre-authorized to run any tool.
      myFlags =   kAuthorizationFlagDefaults |
                      kAuthorizationFlagInteractionAllowed |
                       kAuthorizationFlagPreAuthorize |
                       kAuthorizationFlagExtendRights;
    
       // This puts the Authorization dialog on the screen
      // and adds the authorization rights to the
       // authorization reference, gAuthorizationRef.
      myStatus = AuthorizationCopyRights 
                     (   gAuthorizationRef, 
                        &myRights, 
                        NULL, 
                        myFlags, 
                        NULL );
      if(myStatus != errAuthorizationSuccess) goto bail;
   }
    
  // If we have a valid authorization reference...
   if ( gAuthorizationRef) {
      myFlags = kAuthorizationFlagDefaults;
   // Get the path for the script to run 
   myStatus = GetScriptPath(myToolPath, scriptName);
      if(myStatus) goto bail;
      myArguments[0] = myToolPath;
      // Finally, execute our script.
      myStatus = AuthorizationExecuteWithPrivileges
                     (   gAuthorizationRef, 
                        "/bin/sh", 
                        myFlags, 
                        myArguments, 
                        &myPipe);
   
      if(myStatus == errAuthorizationSuccess) {
         for(;;) {
            // Scripts send output back through myPipe which is
             // redisplayed on standard out
            int bytesRead = read
                                    (fileno(myPipe),
                               myReadBuffer, 
                              sizeof(myReadBuffer))
      // No more data!
            if(bytesRead < 1) 
               break;
            write(fileno(stdout), myReadBuffer, bytesRead);
         }
      } 
      else 
         printf("AuthorizationExecuteWithPrivileges "
                     "returned %ld\n", myStatus);
   }
bail:
   return myStatus;
}

DoInstall creates an Authorization reference if it doesn't already exist, and uses that authorization reference to allow the user to add privileges to execute the shell script passed to it. In addition, any output produced by the script will be echoed on standard out. This can be a valuable debugging aid when a script is giving you trouble as you can use standard shell commands like "echo" and "pwd" in your script and see the output in your Run window in Project Builder.

Launch the application

This is accomplished by calling [NSWorkspace launchApplication].

Listing 4: main.m

main.m

LaunchMainApplication gets a path to the main application located within the bundle and launches it.

void LaunchMainApplication() {
   // Get the ref to the main app in the resources folder
   CFURLRef url = CFBundleCopyResourceURL(
                            CFBundleGetMainBundle(),
                            CFSTR("MyApp.app"), 
                           NULL, NULL);
    NSString         *path = [NSString stringWithFormat:
                         @"%@Contents/MacOS/MyApp", 
                        [((NSURL *)url) path]];
    
  [[NSWorkspace sharedWorkspace] launchApplication:path];
}

An installer script

Once the user has granted the application permission to perform privileged commands, you can do anything you need to install your support item in the script.

    ***Warning***. Your script now has omniscient powers! You can cause irreparable damage to the user's system in your script if you're not careful.

Listing 5: InstallFramework.sh

InstallFramework.sh

Here's an example script which copies a framework to the system and calls update_prebinding to 
calculate the locations of functions within a library so applications will launch faster.

#!/bin/sh
# check if the global frameworks directory exists, 
# create it if not
if [ ! -d /Library/Frameworks ]; then
     # create
   mkdir /Library/Frameworks
     # set group to the administrative group
   chgrp staff /Library/Frameworks
     # allow group users to modify
   chmod 775 /Library/Frameworks
fi
# make sure the framework exists within our application
if [ -d \
   MyApp.app/Contents/Resources/SupportItems/\
MyFramework.framework ]; then
   # check if the framework exists in /Library/Frameworks
    # delete it if it is
  if [ -d /Library/Frameworks/MyFramework.framework ]; then
    rm -rf /Library/Frameworks/MyFramework.framework
   fi
    
   # copy our framework to the system   
   cp -Rp \   
      MyApp.app/Contents/Resources/SupportItems/\
Myframework.framework \
      /Library/Frameworks
   
   # change file modes on the new framework  
   chmod -R ogu+r \
       /Library/Frameworks/MyFramework.framework
  
   # call update_prebing  
    /usr/bin/update_prebinding  -files \
          /Library/Frameworks/MyFramework.framework
else
      # Perhaps you forgot to add the file to the framework?
    echo MyFramework.framework is missing from build!
fi

Last Step - "Move" Scripts

When you're building the Installer, Project Builder makes it easy for you to move your support items and main application into the Resources folder by adding an extra step to the build process. Select the Targets tab on the main project window and select the <MySelfInstaller> target. From the Project Menu, select "New Build Phase" and the "New Shell Script Build Phase" submenu item.

In the "Shell:" text area enter "/bin/sh" if this is the shell you normally work with. (Note you can use any shell you'd like). In the second text area enter "exec ./moveMyFramework.sh". Let's look at an example of the script:

Listing 6: moveMyFramework.sh

MoveMyFramework.sh

This script copies the framework from a sibling directory into our SupportItems folder.

#!/bin/sh
# if the framework already exists, delete it
if [ -d "build/MyApp.app/Contents/Resources/\
SupportItems/MyFramework.framework" ]; then
   rm -rf \
      "build/MyApp.app/Contents/Resources/\
SupportItems/MyFramework.framework"
fi
# Check the "SupportItems" folder actually exists
if [ ! -d \
   "build/MyApp.app/Contents/Resources/SupportItems" ]; then
   mkdir \
 "build/MyApp.app/Contents/Resources/SupportItems"
fi
# Finally, copy the framework
cp -Rp ../MyFramework/build/MyFramework.framework \
    build/MyApp.app/Contents/Resources/SupportItems

Don't get confused by the multiple references to "MyApp". Remember, the goal is to make the user unaware they're actually running multiple applications. You'll want to add your application's icons to the self-installer to complete the effect.

Conclusion

This approach has numerous advantages to rolling out new versions of your application and provides a very nice user experience, as the user only has to authorize once during the initial run of the application. Absent is a way to un-install the application and supporting files. This is left as an exercise for the reader.

References:

Authorization Services Reference:

http://developer.apple.com/documentation/Security/Reference/authorization_ref/


Ken Wieschhoff lives near Atlanta and works for Altea Therapeutics by day as an 8051 embedded programmer (and some Windows MFC/GUI stuff) and Eskape Labs by night where he does Cocoa programming (and occasionally device drivers) for their MyTV product line. Weekends you can find him scuba diving, riding his new Honda Valkyrie Rune, pickin' a guitar and eating grits. He can be reached at weesh@mindspring.com.

 
AAPL
$102.47
Apple Inc.
+2.71
MSFT
$44.88
Microsoft Corpora
+0.80
GOOG
$526.54
Google Inc.
+5.70

MacTech Search:
Community Search:

Software Updates via MacUpdate

RapidWeaver 6.0 - Create template-based...
RapidWeaver is a next-generation Web design application to help you easily create professional-looking Web sites in minutes. No knowledge of complex code is required, RapidWeaver will take care of... Read more
NTFS 12.0.39 - Provides full read and wr...
Paragon NTFS breaks down the barriers between Windows and OS X. Paragon NTFS effectively solves the communication problems between the Mac system and NTFS, providing full read and write access to... Read more
RestoreMeNot 2.0.3 - Disable window rest...
RestoreMeNot provides a simple way to disable the window restoration for individual applications so that you can fine-tune this behavior to suit your needs. Please note that RestoreMeNot is designed... Read more
Macgo Blu-ray Player 2.10.9.1750 - Blu-r...
Macgo Mac Blu-ray Player can bring you the most unforgettable Blu-ray experience on your Mac. Overview Macgo Mac Blu-ray Player can satisfy just about every need you could possibly have in a Blu-ray... Read more
Apple iOS 8.1 - The latest version of Ap...
The latest version of iOS can be downloaded through iTunes. Apple iOS 8 comes with big updates to apps you use every day, like Messages and Photos. A whole new way to share content with your family.... Read more
TechTool Pro 7.0.5 - Hard drive and syst...
TechTool Pro is now 7, and this is the most advanced version of the acclaimed Macintosh troubleshooting utility created in its 20-year history. Micromat has redeveloped TechTool Pro 7 to be fully 64... Read more
PDFKey Pro 4.0.2 - Edit and print passwo...
PDFKey Pro can unlock PDF documents protected for printing and copying when you've forgotten your password. It can now also protect your PDF files with a password to prevent unauthorized access and/... Read more
Yasu 2.9.1 - System maintenance app; per...
Yasu was originally 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... Read more
Hazel 3.3 - Create rules for organizing...
Hazel is your personal housekeeper, organizing and cleaning folders based on rules you define. Hazel can also manage your trash and uninstall your applications. Organize your files using a... Read more
Autopano Giga 3.7 - Stitch multiple imag...
Autopano Giga allows you to stitch 2, 20, or 2,000 images. Version 3.0 integrates impressive new features that will definitely make you adopt Autopano Pro or Autopano Giga: Choose between 9... Read more

Latest Forum Discussions

See All

Fiete – A Day on a Farm Review
Fiete – A Day on a Farm Review By Amy Solomon on October 21st, 2014 Our Rating: :: A MEMORABLE EXPERIENCEUniversal App - Designed for iPhone and iPad Fiete – A day on a farm in an interactive app for young children full of... | Read more »
Tilt to Live: Gauntlet’s Revenge is Almo...
Tilt to Live: Gauntlet’s Revenge is Almost Here Posted by Jessica Fisher on October 21st, 2014 [ permalink ] One Man Left has announced the official release date of Tilt to Live: Gauntlet’s Re | Read more »
Sago Mini Monsters Celebrates Halloween...
Sago Mini Monsters Celebrates Halloween with Fun Costumes and Special Treats. Posted by Jessica Fisher on October 21st, 2014 [ permal | Read more »
Inferno 2 Review
Inferno 2 Review By Andrew Fisher on October 21st, 2014 Our Rating: :: TWIN STICK GOODNESSUniversal App - Designed for iPhone and iPad With tight controls and awesome, stark visuals, Inferno 2 is loads of fun.   | Read more »
Clips Review
Clips Review By Jennifer Allen on October 21st, 2014 Our Rating: :: CONVENIENT PASTINGUniversal App - Designed for iPhone and iPad Making copying and pasting more powerful than usual, Clips is a great way to move stuff around.   | Read more »
MonSense Review
MonSense Review By Jennifer Allen on October 21st, 2014 Our Rating: :: ORGANIZED FINANCESiPhone App - Designed for the iPhone, compatible with the iPad Organize your finances with the quick and easy to use, MonSense.   | Read more »
This Week at 148Apps: October 13-17, 201...
Expert App Reviewers   So little time and so very many apps. What’s a poor iPhone/iPad lover to do? Fortunately, 148Apps is here to give you the rundown on the latest and greatest releases. And we even have a tremendous back catalog of reviews; just... | Read more »
Angry Birds Transformers Review
Angry Birds Transformers Review By Jennifer Allen on October 20th, 2014 Our Rating: :: TRANSFORMED BIRDSUniversal App - Designed for iPhone and iPad Transformed in a way you wouldn’t expect, Angry Birds Transformers is a quite... | Read more »
GAMEVIL Announces the Upcoming Launch of...
GAMEVIL Announces the Upcoming Launch of Mark of the Dragon Posted by Jessica Fisher on October 20th, 2014 [ permalink ] Mark of the Dragon, by GAMEVIL, put | Read more »
Interview With the Angry Birds Transform...
Angry Birds Transformers recently transformed and rolled out worldwide. This run-and-gun title is a hit with young Transformers fans, but the ample references to classic Transformers fandom has also earned it a place in the hearts of long-time... | Read more »

Price Scanner via MacPrices.net

Select MacBook Airs $100 off MSRP, free shipp...
B&H Photo has 2014 a couple of MacBook Airs on sale for $100 off MSRP. Shipping is free, and B&H charges NY sales tax only. They also include free copies of Parallels Desktop and LoJack for... Read more
13-inch 2.5GHz MacBook Pro on sale for $100 o...
B&H Photo has the 13″ 2.5GHz MacBook Pro on sale for $999.99 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
Strong iPhone, Mac And App Store Sales Drive...
Apple on Monday announced financial results for its fiscal 2014 fourth quarter ended September 27, 2014. The Company posted quarterly revenue of $42.1 billion and quarterly net profit of $8.5 billion... Read more
Apple Posts How-To For OS X Recovery
OS X 10.7 Lion and later include OS X Recovery. This feature includes all of the tools you need to reinstall OS X, repair your disk, and even restore from a Time Machine backup. OS X Recovery... Read more
Mac OS X Versions (Builds) Supported By Vario...
Apple Support has posted a handy resource explaining which Mac OS X versions (builds) originally shipped with or are available for your computer via retail discs, downloads, or Software Update. Apple... Read more
Deals on 2011 13-inch MacBook Airs, from $649
Daily Steals has the Mid-2011 13″ 1.7GHz i5 MacBook Air (4GB/128GB) available for $699 with a 90 day warranty. The Mid-2011 13″ 1.7GHz i5 MacBook Air (4GB/128GB SSD) is available for $649 at Other... Read more
2013 15-inch 2.0GHz Retina MacBook Pro availa...
B&H Photo has leftover previous-generation 15″ 2.0GHz Retina MacBook Pros now available for $1599 including free shipping plus NY sales tax only. Their price is $400 off original MSRP. B&H... Read more
Updated iPad Prices
We’ve updated our iPad Air Price Tracker and our iPad mini Price Tracker with the latest information on prices and availability from Apple and other resellers, including the new iPad Air 2 and the... Read more
Apple Pay Available to Millions of Visa Cardh...
Visa Inc. brings secure, convenient payments to iPad Air 2 and iPad mini 3as well as iPhone 6 and 6 Plus. Starting October 20th, eligible Visa cardholders in the U.S. will be able to use Apple Pay,... Read more
Textkraft Pocket – the missing TextEdit for i...
infovole GmbH has announced the release and immediate availability of Textkraft Pocket 1.0, a professional text editor and note taking app for Apple’s iPhone. In March 2014 rumors were all about... Read more

Jobs Board

Senior Event Manager, *Apple* Retail Market...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global event strategy. Delivering an overarching brand story; in-store, Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Project Manager / Business Analyst, WW *Appl...
…a senior project manager / business analyst to work within our Worldwide Apple Fulfillment Operations and the Business Process Re-engineering team. This role will work Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Position Opening at *Apple* - Apple (United...
…customers purchase our products, you're the one who helps them get more out of their new Apple technology. Your day in the Apple Store is filled with a range of Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.