The Wisdom of Quinn

Informative DevForum posts from everyone's favorite DTS member. Share and Enjoy®

The quick way to see updates is to follow the bouncing balls.

• New Posts 🟢
• Updated Posts 🟡
• Deprecated Posts 🔴

While the New and Updated flags will change with each update, the Deprecated flag is forever. Luckily for us, deprecated posts have been replaced by official documentation.

For a comprehensive list of updates, see the CHANGELOG

Resource Pages

Lists and links of Apple resources that The Eskimo finds useful.

• App Sandbox Resources | (PDF) 🟡
• Background Tasks Resources | (PDF)
• Code Signing Resources | (PDF) 🟡
• Debugging Resources | (PDF)
• Files and Storage Resources | (PDF) 🟡
• Network Extension Resources | (PDF) 🟡
• Networking Resources | (PDF) 🟡
• Networking Resources (Old) | (PDF)
• Notarisation Resources | (PDF)
• Security Resources | (PDF)
• Service Management Resources | (PDF)
• TabularData Resources | (PDF)
• Trusted Execution Resources | (PDF) 🟡
• XPC Resources | (PDF) 🟡

Code Signing

Everybody loves code signing!

• A Peek Behind the Code Signing Curtain | (PDF)
• Certificate Signing Requests Explained | (PDF)
• Creating Distribution-Signed Code for Mac | (PDF)
• --deep Considered Harmful | (PDF)
• Fixing an untrusted code signing certificate | (PDF)
• Isolating Code Signing Problems from Build Problems | (PDF)
• KEXT Code Signing Problems | (PDF)
• Manual Code Signing Example | (PDF)
• Resolving Code Signing Crashes on Launch | (PDF)
• Resolving errSecInternalComponent errors during code signing | (PDF)
• Signing a Mac Product For Distribution | (PDF)
• Signing code for older versions of macOS on Apple Silicon | (PDF)

Distribution

App Store, Provisioning Profiles, Developer ID, and Notarization.

• App Translocation Notes | (PDF)
• Background items showing up with the wrong name | (PDF)
• Don’t Run App Store Distribution-Signed Code | (PDF)
• Embedding a Command-Line Tool in a Sandboxed App | (PDF) 🔴
• Error 1048 When Notarising | (PDF)
• Exporting a Developer ID Network Extension | (PDF) 🟢
• Finding a Capability’s Distribution Restrictions | (PDF)
• Identifying a Cloud Managed Signing Certificate | (PDF)
• Notarisation Fundamentals | (PDF)
• Notarisation and the macOS 10.9 SDK | (PDF)
• Notarising an Installer Package Containing a KEXT | (PDF)
• Packaging a Daemon with a Provisioning Profile | (PDF) 🔴
• Packaging Mac Software for Distribution | (PDF)
• TestFlight, Provisioning Profiles, and the Mac App Store | (PDF) 🟡
• The Care and Feeding of Developer ID | (PDF) 🟡
• The Pros and Cons of Stapling | (PDF)
• Resolving Gatekeeper Problems | (PDF)
• Resolving Gatekeeper Problems Caused by Dangling Load Command Paths | (PDF)
• Sandboxed Helper Tool Crashing in libsystem_secinit | (PDF)
• Testing a Notarised Product | (PDF)
• What exactly is a provisioning profile? | (PDF) 🔴

Filesystems

Bits on disk.

• Create a Zip Archive With This One Weird Trick | (PDF)
• Extended Attributes and Zip Archive | (PDF)
• On File System Permissions | (PDF) 🟡
• Unpacking Apple Archives | (PDF)
• Whither FileHandle? | (PDF)

iOS Background Activities

Y U KILL MAH PROCESS?

• iOS Background Execution Limits | (PDF)
• Testing Background Session Code | (PDF)
• UIApplication Background Task Notes | (PDF)

Security

Shhh… it's a secret.

• App Groups: macOS vs iOS: Fight! | (PDF)
• BSD Privilege Escalation on macOS | (PDF)
• Calling Security Framework from Swift | (PDF)
• Data Vault Info | (PDF)
• Defining An App Group Shared Between macOS and iOS | (PDF)
• Error -34018 errSecMissingEntitlement | (PDF)
• Importing Cryptographic Keys | (PDF)
• Intermittent -34018 errors from users in the field | (PDF)
• On Cryptographic Key Formats | (PDF)
• Remote Debugging for Authorization Plugins | (PDF)
• Resolving App Sandbox Inheritance Problems | (PDF)
• Resolving Hardened Runtime Incompatibilities | (PDF)

Keychains

• App ID Prefix Change and Keychain Access | (PDF)
• Keychain sharing | (PDF)
• On Mac Keychains | (PDF) 🔴
• SecItem attributes for keys | (PDF)
• SecItem: Fundamentals | (PDF) 🟡
• SecItem: Pitfalls and Best Practices | (PDF) 🟡
• Troubleshooting -34018 Keychain Errors | (PDF)

Logging

Tell me about what happened.

• Implementing Your Own Crash Reporter | (PDF)
• Fetching the Notary Log | (PDF)
• On Log Noise | (PDF)
• Parsing Dates Without Times | (PDF)
• Recording Private Data in the System Log | (PDF)
• Unified Logging from the Kernel | (PDF)
• Using a Sysdiagnose Log to Debug a Hard-to-Reproduce Problem | (PDF 🟢
• Viewing Sandbox Violation Reports | (PDF) 🔴
• Your Friend the System Log | (PDF) 🟡

Low-Level Fiddly Bits

Get down in the guts.

• Availability of Low-Level APIs | (PDF) 🟢
• Avoid Dispatch Global Concurrent Queues | (PDF)
• Running a Child Process with Standard Input and Output | (PDF)
• Swift 3 and BSD Sockets | (PDF)
• WWDC 2010 Session 207 Run Loops Section | (PDF)

Debugging

• Accessing Global Variables on Apple Silicon | (PDF)
• Language Exception from RCTFatal | (PDF)
• Using a Link Map to Track Down a Symbol’s Origin | PDF

Libraries and Frameworks

• An Apple Library Primer | (PDF) 🟡
• Async Signal Safe Functions vs Dyld Lazy Binding | (PDF)
• Dynamic Library Full Path Alternative | (PDF) 🟢
• Dynamic Library Identification | (PDF) 🟢
• Dynamic Library Standard Setup for Apps | (PDF) 🟢
• Resolving Library Loading Problems | (PDF)

Memory

• Handling shouldFreeInfo Parameters | (PDF)
• Objective-C Memory Management for Swift Programmers | (PDF)
• On Free Memory | (PDF)
• Standard Memory Debugging Tools | (PDF)
• The Peril of the Ampersand | (PDF)

XPC

• Testing and Debugging XPC Code With an Anonymous Listener | (PDF)
• XPC and App-to-App Communication | (PDF)

Networking

Making this talk to that.

BSD Sockets

• Calling BSD Sockets from Swift | (PDF)
  • QSocket: Addresses | (PDF)
  • QSocket: DNS | (PDF)
  • QSocket: Interfaces | (PDF)
  • QSocket: System Additions | (PDF)
  • QSocket: I/O | (PDF)
  • QSocket: Socket Options | (PDF)

Non-Standard Networking

• Extra-ordinary Networking | (PDF) 🟡
  • The iOS Wi-Fi Lifecycle | (PDF 🟡
  • Network Interface Concepts | (PDF)
  • Network Interface Techniques | (PDF)
  • Network Interface APIs | (PDF)
  • Running an HTTP Request over WWAN | (PDF)
  • Showing Connection Information in an iOS Server | (PDF)
  • Don’t Try to Get the Device’s IP Address | (PDF)
  • Working with a Wi-Fi Accessory | (PDF) 🟡

Debugging

• Debugging a Network Extension Provider | (PDF)
• Debugging HTTP Proxies and Certificate Transparency | (PDF) 🟢
• Debugging HTTP Server-Side Errors | (PDF)
• Investigating Network Latency Problems | (PDF)
• Network Debugging articles | (PDF)
• Network Debugging in the Field | (PDF)
• Using mitmproxy to Analyse HTTP[S] Requests | (PDF)

Extensions

• A Peek Behind the NECP Curtain | (PDF)
• NEHotspotHelper pseudo API | (PDF)
• Network Extension and VPN Glossary | (PDF) 🟢
• Network Extension Framework Entitlements | (PDF)
• Network Extension Provider Memory Strategy | (PDF)
• Networking in a Short-Lived Extension | (PDF) 🟡

General

• Five Reasons Why Synchronous Networking Is Bad | (PDF)
• iOS Network Signal Strength | (PDF)
• Maintaining a TCP Connection in the Background | (PDF)
• Moving to Fewer, Larger Transfers | (PDF) 🟡
• NSURLCache and Byte Ranges | (PDF)
• On FTP | (PDF)
• Using the Multicast Networking Additional Capability | (PDF) 🔴
• Wi-Fi Fundamentals | (PDF)

IPv6

• IPv6 and App Review | (PDF)
• IPv6 Address Synthesis on Older Systems | (PDF)
• Supporting IPv6-only Networks | (PDF)

Local Network

• Getting Started with Bonjour | (PDF) 🟢
• Triggering the Local Network Privacy Alert | (PDF)
• Local Network Privacy FAQ | (PDF) 🟡
  • FAQ-1: What is a local network? | (PDF)
  • FAQ-2: What operations require local network access? | (PDF)
  • FAQ-3: What operations require the multicast entitlement? | (PDF)
  • FAQ-4: Do I need the multicast entitlement? | (PDF)
  • FAQ-5: I’ve been granted the multicast entitlement; how do I enable it? | (PDF)
  • FAQ-6: Can App Clips access the local network? | (PDF)
  • FAQ-7: How does local network privacy work with app extensions? | (PDF)
  • FAQ-8: How do I explicitly trigger the local network privacy alert? | (PDF)
  • FAQ-9: How do I tell whether I’ve been granted local network access? | (PDF)
  • FAQ-10: How do I use the unsatisfied reason property? | (PDF)
  • FAQ-11: Do I need a local network usage description property? | (PDF)
  • FAQ-12: Can I test on the simulator? | (PDF)
  • FAQ-13: Once my app has displayed the local network privacy alert, how can I reset its state so that it shows again? | (PDF)
  • FAQ-14: How do I map my Multipeer Connectivity service type to an entry in the Bonjour services property? | (PDF)
  • FAQ-15: My app presents the local network privacy alert unexpectedly. Is there a way to track down the cause? | (PDF)
  • FAQ-16: On a small fraction of devices my app fails to present the local network privacy alert. What’s going on? | (PDF) 🟢
  • FAQ-17: Why does local network privacy get confused when I install two variants of my app? | (PDF) 🟢

Security

• App Transport Security | (PDF)
• Customising TLS Server Trust Evaluation Considered Harmful | (PDF)
• Implementing Secure Transport I/O Functions | (PDF)- TLS for App Developers | (PDF)
• TLS For Accessory Developers | (PDF)

Odds and Ends

General info and some puzzles.

• Bug Reporting: How and Why? | (PDF)
• Investigating Third-Party IDE Integration Problems | (PDF) 🟢
• KWN & ESK’s Puzzle Page: Mutation Madness | (PDF)
• Posting a Crash Report | (PDF)
• What is an exception? | (PDF)
• Quinn’s Top Ten DevForums Tips | (PDF)

Disclaimer

All of this content is subject to the license of the Apple Developer Forums. I make no claims to any of it. This page provides PDF files as an archival format, but the live links to the articles are the preferred access method.