[lldb-dev] [llvm-dev] Remotely launching a new process with LLDB
Greg Clayton via lldb-dev
lldb-dev at lists.llvm.org
Tue Nov 28 11:16:18 PST 2017
I will update the remote.html web page with any info that is missing! I was about to go write the web page... Didn't realize we had one.
> On Nov 28, 2017, at 11:08 AM, Jim Ingham <jingham at apple.com> wrote:
>
> Hey, Greg,
>
> If you have a moment, could you add what isn't already there of this useful info to http://lldb.llvm.org/remote.html? The correct answer to this question should be "read http://lldb.llvm.org/remote.html" but that doesn't seem as immediately useful as your description.
>
> Jim
>
>
>> On Nov 28, 2017, at 11:02 AM, Greg Clayton via lldb-dev <lldb-dev at lists.llvm.org> wrote:
>>
>> lldb-server can be launched in two ways:
>> 1 - platform connection mode
>> 2 - debug a single process mode
>>
>> LLDB has two ways to connect to a remote process:
>> 1 - you launch the GDB server yourself and attach to it
>> 2 - you launch lldb-server in platform mode, connect to the platform, and then just debug like you normally would on a local machine.
>>
>> When you launch the GDB server yourself as mentioned in step 1 above, you can do:
>>
>> remote.foo.com% lldb-server gdbserver 1234 -- /bin/ls -lAF
>>
>> Then attach to it yourself:
>>
>> local.foo.com% lldb
>> (lldb) process connect connect://remote.foo.com:1234
>>
>>
>> When you want an lldb-server to do the work of startup on the GDB server for you:
>>
>> remote.foo.com% lldb-server platform --server --listen 1234
>>
>> Then you select the remote platform and connect to it with LLDB:
>>
>> local.foo.com% lldb
>> (lldb) platform select remote-macosx
>> Platform: remote-macosx
>> Connected: no
>> (lldb) platform connect connect://localhost:1234
>> Platform: remote-macosx
>> Triple: x86_64-apple-macosx
>> OS Version: 10.12.6 (16G1036)
>> Kernel: Darwin Kernel Version 16.7.0: Wed Oct 4 00:17:00 PDT 2017; root:xnu-3789.71.6~1/RELEASE_X86_64
>> Hostname: gclayton-pro
>> Connected: yes
>> WorkingDir: /Users/gclayton
>>
>> Now LLDB has a "platform" connection to the remote machine that can start up the GDB server for you. Also note that the platform states what its working directory is (which defaults to the directory it was launched in).
>>
>> If you want to launch a locally built executable on the remote side, now you can do:
>>
>> (lldb) file a.out
>> (lldb) run
>>
>> This will cause LLDB to create a target with the "a.out" executable that you cross built. Then you "run" and this will cause LLDB to upload "a.out" to the platform's current working directory only if the file has changed. The platform connection allows us to transfer files, but also allows us to get the MD5 checksum of the file on the other end in the current working directory and only upload the file if it has changed. If you don't want the "a.out" executable to be uploaded to the current platform working directory you can do to specify where the executable will be uploaded to:
>>
>> (lldb) file /local/path/to/a.out
>> # Get the lldb.SBModule for "/local/path/to/a.out" in the local variable named "m":
>> (lldb) script m = lldb.target.module['a.out']
>> # Set the platform path for the executable to "/bin/a.out":
>> (lldb) script m.SetPlatformFileSpec("/bin/a.out")
>> (lldb) run
>>
>> Now when you run your program, the program will be uploaded to "/bin/a.out" instead of the the current working directory of the platform.
>>
>> You can also change the platform working directory if you are connected to the platform
>>
>> (lldb) platform settings -w /tmp
>>
>> And you can verify it worked using "platform status":
>>
>> (lldb) platform status
>> Platform: remote-macosx
>> Triple: x86_64-apple-macosx
>> OS Version: 10.12.6 (16G1036)
>> Kernel: Darwin Kernel Version 16.7.0: Wed Oct 4 00:17:00 PDT 2017; root:xnu-3789.71.6~1/RELEASE_X86_64
>> Hostname: gclayton-pro
>> Connected: yes
>> WorkingDir: /private/tmp
>>
>>
>> If you want to attach to a remote process, you can list the processes if you are connected:
>>
>> (lldb) platform process list
>> 223 matching processes were found on "remote-macosx"
>> PID PARENT USER TRIPLE NAME
>> ====== ====== ========== ======================== ============================
>> 68881 96266 (null) x86_64-apple-macosx lldb-server
>> 68639 90652 x86_64-apple-macosx lldb
>> 67830 1 x86_64-apple-macosx helpd
>> 67737 1 x86_64-apple-macosx com.apple.iCloudHelper
>>
>> ...
>>
>> Then attach:
>>
>> (lldb) attach 68639
>>
>> Let me know if you have any questions.
>>
>> Greg Clayton
>>
>>
>>> On Nov 28, 2017, at 9:29 AM, Adrian Prantl via lldb-dev <lldb-dev at lists.llvm.org> wrote:
>>>
>>> I would recommend asking this on the lldb mailing list instead.
>>>
>>> -- adrian
>>>
>>>> On Nov 26, 2017, at 8:30 AM, Lior Halphon via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>>>>
>>>> I'm trying to remotely launch and debug a new process with lldb without much success.
>>>>
>>>> Attaching to an already launched process works well by running these commands:
>>>>
>>>> process connect <url>
>>>> process attach -P gdb-remote --pid <pid>
>>>>
>>>> But if I want debugserver to launch the executable by itself I'm running into troubles. Especially, I have no clue what arguments should I pass to
>>>> target
>>>> create
>>>> .
>>>>
>>>> According to this page LLDB "will transparently take care of [..] downloading the executable in order to be able to debug", yet
>>>> target
>>>> create
>>>> seem to always require a local file. If I specify the remote file via -r I get either
>>>> unable
>>>> to open target file
>>>> or
>>>> remote
>>>> --> local transfer without local path is not implemented yet
>>>> errors. If I set the target to a local file (such as a local copy of the remote's loader executable) without using -r, then attempt to run
>>>> process
>>>> launch -p gdb-remote -s <remote path>
>>>> LLDB will attempt running the local path on the remote machine and fail.
>>>>
>>>> What are the correct commands I need to use in order to launch a remote process?
>>>>
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
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>>
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