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 Missing/outdated items are installed using Apple's Authorization Services API.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.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Bartender 3.0.32 - Organize your menu-ba...
Bartender lets you organize your menu-bar apps by hiding them, rearranging them, or moving them to Bartender's Bar. You can display the full menu bar, set options to have menu-bar items show in the... Read more
Adobe Animate CC 2018 18.0.1.115 - Anima...
Animate CC 2018 is available as part of Adobe Creative Cloud for as little as $19.99/month (or $9.99/month if you're a previous Flash Professional customer). Animate CC 2018 (was Flash CC) lets you... Read more
Adobe Lightroom Classic CC 7.1 - Import,...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more
ExpanDrive 6.1.8 - 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
ExpanDrive 6.1.8 - 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
DiskCatalogMaker 7.2.7 - Catalog your di...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast Finder-like intuitive look and feel Super-fast search algorithm Can compress catalog data for... Read more
DiskCatalogMaker 7.2.7 - Catalog your di...
DiskCatalogMaker is a simple disk management tool which catalogs disks. Simple, light-weight, and fast Finder-like intuitive look and feel Super-fast search algorithm Can compress catalog data for... Read more
Iridient Developer 3.2.1 - Powerful imag...
Iridient Developer (was RAW Developer) is a powerful image-conversion application designed specifically for OS X. Iridient Developer gives advanced photographers total control over every aspect of... Read more
BusyContacts 1.2.7 - Fast, efficient con...
BusyContacts is a contact manager for OS X that makes creating, finding, and managing contacts faster and more efficient. It brings to contact management the same power, flexibility, and sharing... Read more
MegaSeg 6.0.5 - Professional DJ and radi...
MegaSeg is a complete solution for pro audio/video DJ mixing, radio automation, and music scheduling with rock-solid performance and an easy-to-use design. Mix with visual waveforms and Magic... Read more

Latest Forum Discussions

See All

The best deals on the App Store this wee...
A new week means new discounts on the App Store. This week's deals run the gamut of action-adventure titles, puzzle games, and one of the best narrative adventure series out there. If you're looking to fill out your mobile gaming library on a... | Read more »
What you need to know about Animal Cross...
We hope you've been hard at work on collecting all of those holiday items in Animal Crossing: Pocket Camp, because you're about to get a whole new list of fun things to do as the game receives its first big update sometime soon. There are a lot of... | Read more »
Reigns: Her Majesty guide - how to use e...
Ruling a kingdom isn't easy--doubly so for a queen whose every decision is questioned by the other factions seeking a slice of power. Reigns: Her Majesty builds on the original game's swipey tactics, adding items that you can use to move the story... | Read more »
The best new games we played this week -...
Friday has crept up on us once again, so it's time to honor the best new games we've played over the past few days. This past week was a pretty exciting one, with the debut of lots of beautiful new indies and some familiar faces returning to the... | Read more »
Portal Knights guide- beginner tips and...
Portal Knights is finally making the jump to iOS and Android, and it's already climbing the ranks to become the next big MMO experience on mobile. This sprawling sandbox game will let you pursue any adventure you wish, whether you want to sling... | Read more »
Reigns: Her Majesty guide - how to swipe...
Reigns: Her Majesty is storming the App Store this week, bringing more tinder-esque kingdom building to eager players everywhere. If you've played the original Reigns, you'll know that leading a kingdom is never easy. It's a careful balancing act... | Read more »
Getting Over It (Games)
Getting Over It 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: A game I madeFor a certain kind of person To hurt them. • Climb up an enormous mountain with nothing but a hammer and a pot.•... | Read more »
Reigns: Her Majesty (Games)
Reigns: Her Majesty 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »
Pocket Legends Adventures guide - how to...
Pocket Legends Adventures is a fun action adventure RPG that takes control when you want it to, but also opens itself for player input, too, if you're looking to tkae a more active role in combat. Regardless of play style, the game can be quite... | Read more »
Portal Knights (Games)
Portal Knights 1.2.4 Device: iOS Universal Category: Games Price: $4.99, Version: 1.2.4 (iTunes) Description: Craft your adventure. Forge your hero. Become the ultimate Portal Knight! | Read more »

Price Scanner via MacPrices.net

Apple Watch Series 2, Certified Refurbished,...
Apple has Certified Refurbished Apple Watch Nike+ Series 2s, 42mm Space Gray Aluminum Case with Anthracite/Black Nike Sport Bands, available for $249 (38mm) or $279 (42mm). The 38mm model was out of... Read more
Apple offers Certified Refurbished 2016 12″ R...
Apple has Certified Refurbished 2016 12″ Retina MacBooks available starting at $949. Apple will include a standard one-year warranty with each MacBook, and shipping is free. The following... Read more
B&H drops price on 13″ 256GB MacBook Air...
B&H has the 13″ 1.8GHz/256GB Apple MacBook Air (MQD42LL/A) now on sale for $1079 including free shipping plus NY & NJ sales tax only. Their price is $120 off MSRP, and it’s the lowest price... Read more
Holiday sale: 9″ iPads starting at $299, take...
MacMall has 9″ WiFi iPads on sale for $30 off including free shipping: – 9″ 32GB WiFi iPad: $299 – 9″ 128GB WiFi iPad: $399 Read more
Green Monday deal: 15″ 2.8GHz MacBook Pro on...
B&H Photo has the 15″ 2.8GHz Space Gray MacBook Pro on sale for $250 off MSRP for today only as part of their Green Monday/Holiday sale. Shipping is free, and B&H charges sales tax for NY... Read more
Green Monday sale: B&H offers 12″ Apple i...
B&H Photo has 12″ iPad Pros on sale for up to $150 off MSRP as part of their Green Monday/Holiday sale. Shipping is free, and B&H charges sales tax in NY & NJ only: – 12″ 64GB WiFi iPad... Read more
Holiday deal: 21″ and 27″ Apple iMacs on sale...
MacMall has 2017 21″ and 27″ Apple iMacs on sale for up to $200 off MSRP. Shipping is free: – 21″ 2.3GHz iMac: $999 $100 off MSRP – 21″ 3.0GHz iMac: $1199 $100 off MSRP – 21″ 3.4GHz iMac: $1379 $120... Read more
Holiday deal: Apple Mac minis for up to $150...
MacMall has Mac minis on sale for up to $100 off MSRP, each including free shipping: – 1.4GHz Mac mini: $399 $100 off MSRP – 2.6GHz Mac mini: $599 $100 off MSRP – 2.8GHz Mac mini: $949 $50 off MSRP... Read more
Beats by Dr. Dre – BeatsX Earphones on sale f...
Best Buy has BeatsX Earphones on sale for $109, $40 off, on their online store. Sale price for online orders only. Choose free store pickup, if available, or choose free shipping. Read more
10″ 64GB WiFi Apple iPad Pros on sale for $59...
MacMall has 10.5″ 64GB Apple iPad Pros on sale for $599 including free shipping. That’s $50 off MSRP and among the lowest prices available for these iPads from any Apple reseller. Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, 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
*Apple* Retail - Multiple Positions - Apple,...
Job Description:SalesSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Information Security - Security Data...
# Apple Information Security - Security Data Analyst Job Number: 113119545 Austin, Texas, United States Posted: 10-Nov-2017 Weekly Hours: 40.00 **Job Summary** This 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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.