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 Missing/outdated items are installed using Apple's Authorization Services API.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
$95.60
Apple Inc.
-2.55
MSFT
$43.16
Microsoft Corpora
-0.42
GOOG
$571.60
Google Inc.
-15.82

MacTech Search:
Community Search:

Software Updates via MacUpdate

OneNote 15.2 - Free digital notebook fro...
OneNote is your very own digital notebook. With OneNote, you can capture that flash of genius, that moment of inspiration, or that list of errands that’s too important to forget. Whether you’re at... Read more
iStat Menus 4.22 - Monitor your system r...
iStat Menus lets you monitor your system right from the menubar. Included are 8 menu extras that let you monitor every aspect of your system. Some features: CPU -- Monitor cpu usage. 7 display... Read more
Ember 1.8 - Versatile digital scrapbook....
Ember (formerly LittleSnapper) is your digital scrapbook of things that inspire you: websites, photos, apps or other things. Just drag in images that you want to keep, organize them into relevant... Read more
OmniPlan 2.3.6 - Robust project manageme...
With OmniPlan, you can create logical, manageable project plans with Gantt charts, schedules, summaries, milestones, and critical paths. Break down the tasks needed to make your project a success,... Read more
Command-C 1.1.1 - Clipboard sharing tool...
Command-C is a revolutionary app which makes easy to share your clipboard between iOS and OS X using your local WiFi network, even if the app is not currently opened. Copy anything (text, pictures,... Read more
Knock 1.1.7 - Unlock your Mac by knockin...
Knock is a faster, safer way to sign in. You keep your iPhone with you all the time. Now you can use it as a password. You never have to open the app -- just knock on your phone twice, even when it's... Read more
Mellel 3.3.6 - Powerful word processor w...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
LibreOffice 4.3.0.4 - Free Open Source o...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
Freeway Pro 7.0 - Drag-and-drop Web desi...
Freeway Pro lets you build websites with speed and precision... without writing a line of code! With it's user-oriented drag-and-drop interface, Freeway Pro helps you piece together the website of... Read more
Drive Genius 3.2.4 - Powerful system uti...
Drive Genius is an OS X utility designed to provide unsurpassed storage management. Featuring an easy-to-use interface, Drive Genius is packed with powerful tools such as a drive optimizer, a... Read more

Latest Forum Discussions

See All

Dawn of the Immortals Review
Dawn of the Immortals Review By Jennifer Allen on July 31st, 2014 Our Rating: :: RESPECTABLE EXPLORATIONUniversal App - Designed for iPhone and iPad Dawn of the Immortals might not re-invent the wheel, but it does tweak it a little... | Read more »
80 Days Review
80 Days Review By Jennifer Allen on July 31st, 2014 Our Rating: :: EPIC ADVENTUREUniversal App - Designed for iPhone and iPad A fantastic and fascinating re-envisioning of the classic novel by Jules Verne, 80 Days is a delightful... | Read more »
Battleheart Legacy Guide
The world of Battleheart Legacy is fun and deep; full of wizards, warriors, and witches. Here are some tips and tactics to help you get the most enjoyment out of this great game. | Read more »
Puzzle Roo Review
Puzzle Roo Review By Jennifer Allen on July 31st, 2014 Our Rating: :: PUZZLE-BASED TWISTUniversal App - Designed for iPhone and iPad A different take on the usual block dropping puzzle game, Puzzle Roo is quite pleasant.   | Read more »
Super Crossfire Re-Release Super Crossfi...
Super Crossfire Re-Release Super Crossfighter Coming Soon, Other Radiangames Titles Go 50% Off Posted by Ellis Spice on July 31st, 2014 [ | Read more »
Hexiled Review
Hexiled Review By Rob Thomas on July 31st, 2014 Our Rating: :: HEX SELLSUniversal App - Designed for iPhone and iPad In space, no one can hear you… spell? Hexiled is a neat concept for a word scramble puzzle, but it doesn’t go too... | Read more »
Summoners War: Sky Arena Passes 10 Milli...
Summoners War: Sky Arena Passes 10 Million Installs! Posted by Jessica Fisher on July 31st, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Deep Loot Review
Deep Loot Review By Jennifer Allen on July 31st, 2014 Our Rating: :: DIVE DEEPUniversal App - Designed for iPhone and iPad Dive deep in this fun explore-em-up that’s a little grind heavy but ultimately quite entertaining.   | Read more »
Despicable Me: Minion Rush is One Year O...
Despicable Me: Minion Rush is One Year Old, Gets its Biggest Update Yet Posted by Jennifer Allen on July 31st, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Fish & Shark Review
Fish & Shark Review By Jordan Minor on July 31st, 2014 Our Rating: :: FLAPPY FISHUniversal App - Designed for iPhone and iPad Fish & Shark’s beauty is only scale deep.   | Read more »

Price Scanner via MacPrices.net

Save up to $130 on an iPad mini with Apple re...
The Apple Store has Certified Refurbished 2nd generation iPad minis with Retina Displays available for up to $130 off the cost of new models, starting at $339. Apple’s one-year warranty is included... Read more
iPad Cannibalization Threat “Overblown”
Seeking Alpha’s Kevin Greenhalgh observes that while many commentators think Apple’s forthcoming 5.5-inch panel iPhone 6 will cannibalize iPad sales, in his estimation, these concerns are being... Read more
Primate Labs Releases July 2014 MacBook Pro P...
Primate Labs’ John Poole has posted Geekbench 3 results for most of the new MacBook Pro models that Apple released on Tuesday. Poole observes that overall performance improvements for the new MacBook... Read more
Apple Re-Releases Bugfixed MacBook Air EFI Fi...
Apple has posted a bugfixed version EFI Firmware Update 2.9 a for MacBook Air (Mid 2011) models. The update addresses an issue where systems may take longer to wake from sleep than expected, and... Read more
Save $50 on the 2.5GHz Mac mini, plus free sh...
B&H Photo has the 2.5GHz Mac mini on sale for $549.99 including free shipping. That’s $50 off MSRP, and B&H will also include a free copy of Parallels Desktop software. NY sales tax only. Read more
Save up to $140 on an iPad Air with Apple ref...
Apple is offering Certified Refurbished iPad Airs for up to $140 off MSRP. Apple’s one-year warranty is included with each model, and shipping is free. Stock tends to come and go with some of these... Read more
$250 price drop on leftover 15-inch Retina Ma...
B&H Photo has dropped prices on 2013 15″ Retina MacBook Pros by $250 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.3GHz Retina MacBook Pro: $2249, $250 off... Read more
More iPad Upgrade Musings – The ‘Book Mystiqu...
Much discussed recently, what with Apple reporting iPad sales shrinkage over two consecutive quarters, is that it had apparently been widely assumed that tablet users would follow a two-year hardware... Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
Best Buy has the 13″ 2.5GHz MacBook Pro available for $999.99 on their online store. Choose free shipping or free instant local store pickup (if available). Their price is $100 off MSRP. Price is... Read more
Save up to $300 on an iMac with Apple refurbi...
The Apple Store has Apple Certified Refurbished iMacs available for up to $300 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free. These are the best prices on... Read more

Jobs Board

*Apple* Retail - Multiple Positions (US) - A...
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. Product Leader, *Apple* Store Apps - Ap...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full Read more
Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full 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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.