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 Missing/outdated items are installed using Apple's Authorization Services API.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
$100.75
Apple Inc.
+0.64
MSFT
$46.36
Microsoft Corpora
-0.08
GOOG
$577.36
Google Inc.
+1.00

MacTech Search:
Community Search:

Software Updates via MacUpdate

QuickBooks 2015 16.0.0.1352 R1 - Financi...
QuickBooks 2015 helps you manage your business easily and efficiently. Organize your finances all in one place, track money going in and out of your business, and spot areas where you can save.... Read more
Mac DVDRipper Pro 5.0.1 - Copy, backup,...
Mac DVDRipper Pro is the DVD backup solution that lets you protect your DVDs from scratches, save your batteries by reading your movies from your hard disk, manage your collection with just a few... Read more
Apple OS X bash Update 1.0 - Fix for sec...
The OS X bash Update fixes a security flaw in the bash UNIX shell on OS X 10.9.5 (also on OS X 10.8 and 10.7 [see Related Links below]). OS X 10.9.5 or later Downloads for OS X 10.8 and OS X 10.7 in... Read more
SyncTwoFolders 2.0.5 - Syncs two user-sp...
SyncTwoFolders simply synchronizes two folders. It supports synchronization across mounted network drives and it is a possibility to run a simulation showing in a log what will be done. Please visit... Read more
FinderPop 2.5.7 - Classic Mac utility, n...
FinderPop is a Universal preference pane that extends OS X's contextual menus using a FinderPop Items folder much as the Apple Menu Items folder used to do for the Apple menu. It has other features... Read more
VueScan 9.4.45 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
LibreOffice 4.3.2.2 - 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
calibre 2.4 - Complete e-library managem...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital... Read more
Default Folder X 4.6.9b1 - Enhances Open...
Default Folder X attaches a toolbar to the right side of the Open and Save dialogs in any OS X-native application. The toolbar gives you fast access to various folders and commands. You just click... Read more
Beamer 2.0.4 - Stream any movie file fro...
Beamer streams to your Apple TV.... Plays any movie file - Just like the popular desktop movie players, Beamer accepts all common formats, codecs and resolutions. AVI, MKV, MOV, MP4, WMV, FLV. To... Read more

Latest Forum Discussions

See All

WW2: Sandbox. Strategy & Tactics (G...
WW2: Sandbox. Strategy & Tactics 1.0.0 Device: iOS Universal Category: Games Price: $9.99, Version: 1.0.0 (iTunes) Description: Sandbox is the unlimited sequel to our Strategy & Tactics: World War II. We've abandoned... | Read more »
apeFilter (Music)
apeFilter 1.0 Device: iOS Universal Category: Music Price: $6.99, Version: 1.0 (iTunes) Description: | Read more »
Shred It! Review
Shred It! Review By Jennifer Allen on September 30th, 2014 Our Rating: :: GORGEOUS BUT BASICUniversal App - Designed for iPhone and iPad It might look lovely, but Shred It! is a pretty shallow endless runner/snowboarding game.   | Read more »
It Came From Canada: Angry Birds: Transf...
Anyone afraid that throwing Transformers into the Angry Birds mix would result in a Michael Bay-level of childhood pillaging can rest easy. While Rovio’s famous fowls may be a 21st century staple, Angry Birds: Transformers wears its affection for... | Read more »
Galaxy Trucker Review
Galaxy Trucker Review By Rob Thomas on September 30th, 2014 Our Rating: :: IN FOR THE LONG HAULiPad Only App - Designed for the iPad We got a great big convoy, rockin’ through the night… the endless night of outer space, that is.... | Read more »
Moon and Sun – children’s book Review
Moon and Sun – children’s book Review By Amy Solomon on September 30th, 2014 Our Rating: Moon and Sun is a fable-like children’s book with lush illustrations.   Developer: Marcio Monteiro Price: $3.99 Version: 1.0 App Reviewed on... | Read more »
Kairosoft Finally Brings The Pyraplex to...
Kairosoft Finally Brings The Pyraplex to iOS Posted by Jessica Fisher on September 30th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Yeti’s Parole Officer Review
Yeti’s Parole Officer Review By Jennifer Allen on September 30th, 2014 Our Rating: Universal App - Designed for iPhone and iPad Yeti’s Parole Officer proves that looks aren’t everything in this entertaining, if plain, piece of... | Read more »
Record Keeper and World Wide Words – Two...
Record Keeper and World Wide Words – Two New Final Fantasy Games Arrive on iOS in Japan Posted by Ellis Spice on September 30th, 2014 [ permalink ] | Read more »
iPollute Review
iPollute Review By Nadia Oxford on September 30th, 2014 Our Rating: :: iPOLLUTE, uPOLLUTEUniversal App - Designed for iPhone and iPad iPollute is a delightful-looking pollution simulator, though it’s a bit light on “game” content... | Read more »

Price Scanner via MacPrices.net

MacBook Airs on sale for $100 off MSRP, start...
Best Buy has the new 2014 MacBook Airs on sale for $100 off MSRP on their online store. Choose free home shipping or free local store pickup (if available). Prices valid for online orders only, in-... Read more
Apple Releases OS X Mavericks bash Update 1.0...
Apple has released a patch update for OS X Mavericks users to address the recently-detected “Shellshock” security bug in BSD UNIX’s bash shell. Apple says only a few Mac users who had manually... Read more
Pivotal Payments Ready for Apple Pay – FlexPo...
Pivotal Payments, a provider of merchant services and global payment processing solutions, has announced its proprietary FlexPoint platform will support credit and debit transactions through Apple’s... Read more
iStabilizer Announces Tabarm — First Friction...
iStabilizer, a specialist in universal lightweight compact tripods, steady cams, dollies, mounts, and remotes for smartphones, tablets, and cameras, announced today the iStabilizer tabArm, the first... Read more
IStabilizer Flex Smartphone Tripod Wins Usa T...
iStabilizer, a specialist in universal lightweight compact tripods, steady cams, and other products for smartphones, tablets, and cameras, has announced today that its iStabilizer Flex smartphone... Read more
13-inch 2.8GHz Retina MacBook Pro on sale for...
B&H Photo has the new 2014 13″ 2.8GHz Retina MacBook Pro on sale for $1699.99 including free shipping plus NY sales tax only. They’ll also include free copies of Parallels Desktop and LoJack for... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has the new 2014 15″ Retina MacBook Pros on sale for up to $150 off MSRP. Shipping is free, and B&H charges NY sales tax only. They’ll also include free copies of Parallels Desktop... Read more
Get Down to Business On Your iPad With Free N...
Utah based Poem LLC has introduced Nexticy 1.0, a full-featured, affordable (Free) forms application for iPad. Nexticy makes it ‘way easy’ to create, store, retrieve and analyze paper-like forms of... Read more
13-inch Retina MacBook Pros on sale for $100...
Best Buy has 13-inch 2.6GHz Retina MacBook Pros on sale for $100 off MSRP on their online store. Choose free shipping or free local store pickup (if available). Prices are for online orders only, in-... Read more
Reports Outline Claimed 12-Inch Macbook Air D...
Blogger Jack March says that according to information he’s received from an anonymous “source familiar with Apple’s plans,” the next-generation MacBook Air will launch in mid-2015 and be available... 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
*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
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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.