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:
|
--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
Alternative Instructions (64bit compatible): Mac
Alternatively if you are on a mac with xcode installed you can follow Peter Steinberger's instructions to add entitlement's to the debugserver that comes with xcode. This will allow you to keep it as a fat binary, which will work on all devices including 64bit iPhone 5S.
You can find Peter's full slides here: https://speakerd.s3.amazonaws.com/presentations/43ca7dd05d120131795d129291fe58eb/Taking_Advantage_of_the_Runtime.pdf and https://speakerdeck.com/steipete/taking-advantage-of-the-runtime which contain more useful tips. Instructions for getting the debugserver to work start on slide 45.
- 1. Mount xcode's developer disk image on your Mac and copy the debugserver binary to your working directory:
hdiutil attach /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/ DeviceSupport/7.0.3\ \(11B508\)/DeveloperDiskImage.dmg cp /Volumes/DeveloperDiskImage/usr/bin/debugserver .
- 2. Save for following as entitlements.plist:
<?xml version="1.0" encoding="UTF-8"?><!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>run-unsigned-code</key>
<true/>
<key>get-task-allow</key> <true/> <key>task_for_pid-allow</key> <true/>
</dict>
</plist>
- 3. Apply the entitlement with codesign:
codesign -s - --entitlements entitlements.plist -f debugserver
Example session
- 1. Copy MobileNotes to your Mac, e.g. to /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 MobileNotes and wait for the remote debugger.
- 3. Launch the debugger and attach it to the remote process:
If using GDB:
- On your Mac, launch /Developer/Platforms/iPhoneOS.platform/Developer/usr/libexec/gdb/gdb-arm-apple-darwin.
- Type the following in gdb:
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/MobileNotes target remote-macosx 192.168.1.101:6789
where 192.168.1.101 should be replaced by the actual IP address of your device. The remote debug connection is now complete.
If using LLDB:
- On your Mac, launch lldb.
- Type the following in lldb:
platform select remote-ios process connect connect://192.168.1.101:6789
- 4. Enter c to continue and do whatever you want.
References
- iphone-debugserver project — http://code.google.com/p/iphone-debugserver/