Debugserver patch on iOS devices

DebugserverIs a console app that as server for remote gdb debugging. It is installed when a device is marked for development. It can be found in/Developer/usr/bin/debugserver. This is also the process invoked by Xcode to debug applications on the device.

Contents [Hide] 1 Command line options 2 Patching for process attaching 3 Example session 4 References

Command line options

DebugserverCan be invoked

debugserver [<options>] host:<port> [<prog-name> <arg1> <arg2> ...]

WhereOptionsCan be:

Option	Effect
- Process	AttachDebugserverToProcess.ProcessCan be a pid or executable name.
-D Integer	Assign the waitfor-duration.
-F ?	?
-G	Turn on debugging.
-I Integer	Assign the waitfor-interval.
-L Filename	Log to file. SetFilenameToStdoutTo log to standard output.
-T	Use task ID instead of process ID.
-V	Verbose.
-W ?	?
-X Method  -- Launch=Method	How to launch the program. Can be one: Auto: Auto-detect the best launch method to use. Fork: Launch program usingFork (2)AndExec (3). Posix: Launch program usingPosix_spawn (2). Spring: Launch program via SpringBoard.
-- Lockdown	Obtain parameters fromLockdown(?)

Patching for process attaching

The vanillaDebugserverCannot attach to any processes due to lack of entitlement to allowTask_for_pid (). An entitlement must be inserted to the binary to allow this.

• 0. cd ~
• 1.Thin the binary becauseLdidDoes not support fat binaries:

lipo -thin armv6 /Developer/usr/bin/debugserver -output ~/debugserver

• 2.Save for followingEnt. xml:

<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"><plist version="1.0"><dict><key>com.apple.springboard.debugapplications</key><true/><key>get-task-allow</key><true/><key>task_for_pid-allow</key><true/><key>run-unsigned-code</key><true/></dict></plist>

• 3.Apply the entitlementLdid:

ldid -Sent.xml debugserver

Example session

Suppose you want to debug your enotes on 3.1. Also suppose you already have the iPhone SDK, and you already have the patchedDebugserverAt ~.

• 1.Copy your enotes to your Mac, e.g./Developer/Platforms/iPhoneOS. platform/Developer/SDKs/iPhoneOS3.1.sdk/Applications/MobileNotes. app/MobileNotes.
• 2.On the device, type:

~/debugserver -x spring host:6789 /Applications/MobileNotes.app/MobileNotes

This will launch your enotes and wait for the remote debugger.

• 3.On your Mac, launch/Developer/Platforms/iPhoneOS. platform/Developer/usr/libexec/gdb-arm-apple-darwin.
• 4.Type the following inGdb:

set shlib-path-substitutions / /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.1.sdk/file /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS3.1.sdk/Applications/MobileNotes.app/MobileNotestarget remote-macosx 192.168.1.101:6789

Where 192.168.1.101 shoshould be replaced by the actual IP address of your device. The remote debug connection is now complete.

• 5.EnterCTo continue and do whatever you want.

References

• Iphone-debugserver project-http://code.google.com/p/iphone-debugserver/