debugserver

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Revision as of 08:23, 14 October 2009 by KennyTM~ (talk | contribs) (Created page with '{{DISPLAYTITLE:debugserver}} <tt>debugserver</tt> is a console app that as server for remote gdb debugging. It is installed when a device is marked for development. It can b…')
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debugserver is 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.

Command line options

debugserver can be invoked with

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

Where options can be:

Option Effect
-a process Attach debugserver to process. The process can 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. Set filename to stdout to 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 of:
  • auto: Auto-detect the best launch method to use.
  • fork: Launch program using fork(2) and exec(3).
  • posix: Launch program using posix_spawn(2).
  • spring: Launch program via SpringBoard.
--lockdown Obtain parameters from lockdown (?)

Patching for process attaching

The vanilla debugserver cannot attach to any processes due to lack of entitlement to allow task_for_pid(). An entitlement must be inserted to the binary to allow this.

  • 0. cd ~
  • 1. Thin the binary because ldid does not support fat binaries:
lipo -thin armv6 /Developer/usr/bin/debugserver -output ~/debugserver
  • 2. Save for following as ent.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 entitlement with ldid:
ldid -Sent.xml debugserver

Example session

TODO.

References