[Lldb-commits] [PATCH] Move argument globbing to Target::Launch from Platform::LaunchProcess.

Zachary Turner zturner at google.com
Thu Feb 19 16:33:55 PST 2015

Is this not something we could solve by writing a function in Host that
behaves the way we'd like it to behave on all platforms?  I mean it might
be an ugly function, but the idea of passing stuff to an external program
is kinda meh.  FWIW launching a process is not a lightweight operation on
windows like it is on other platforms, and there's actually noticeable
overhead.  So it would be great if we could remove dependencies on external

On Thu Feb 19 2015 at 4:30:24 PM Enrico Granata <egranata at apple.com> wrote:

> IIUC, glob() does not perform environment variables expansion - and even
> support for ~ expansion is an extension that is not generally POSIX
> compliant
> These are things we’d like to preserve (definitely we would like to have
> these abilities on OS X)
> On Feb 19, 2015, at 4:23 PM, Oleksiy Vyalov <ovyalov at google.com> wrote:
> On Linux the platform is used to launch a process only when LLGS_LOCAL
> mode is on - otherwise, process plugin is used.
> I'm wondering whether we need the standalone binary argdumper for globbing
> - potentially, we may just use glob function on Linux and OSX. For remote
> execution there might be a new protocol extension command (e.g., qGlobArgs)
> which either calls glob or runs argdumper.
> On Thu, Feb 19, 2015 at 3:12 PM, Zachary Turner <zturner at google.com>
> wrote:
>> There's currently a lot of ways to launch processes, and the interactions
>> that lead to specific methods being chosen can be a bit confusing sometimes.
>> Out of curiosity, if a plugin supports launching under a debugger
>> directly, why is the separate start stopped / attach / resume algorithm
>> used?  It seems more straightforward.
>> If someone gets themselves through that codepath, argdumper won't be
>> used.  Which is confusing if you're outside looking in at the API.  From
>> the outside you just see the process gets launched using a supported
>> mechanism for launching processes, and it ignores the flag.
>> On Thu Feb 19 2015 at 3:03:16 PM Greg Clayton <gclayton at apple.com> wrote:
>>> They will only if you teach your platform to launch your processes. I
>>> believe the Windows platform is the only platform that doesn't do process
>>> launching via the platform. Am I wrong? If your platform supports it, it
>>> should launch your process in a stopped state and then your Process plug-in
>>> is simply asked to attach to that process.
>>> So if you wanted this to be supported, you will need to teach your
>>> windows platform to support the PlatformWindows::GlobArguments() which
>>> means you will launch the arg_dumper though cmd.exe and let the cmd.exe do
>>> any glowing and any expansion that it wants to, and parse the output.
>>> Enrico will check in a method for PlatformPOSIX::GlobArguments() which
>>> launches through a shell. I can't remember where we can get the default
>>> shell, but I seem to remember that we have the default shell that we can
>>> get from the host, so we could add this implementation in
>>> "Platform::GlobArguments()" and if "IsHost()" returns true, get the default
>>> shell from the host and launch the arg_dumper and then parse the output.
>>> This probably should be a method on ProcessLaunchInfo so that it fixes
>>> up its arguments and uses the target's platform to do the glob expansion.
>>> So the changes would be:
>>> 1 - add a method to ProcessLaunchInfo that gets passed a target and
>>> allows it to fixup arguments and environment variables in a new
>>> ProcessLaunchInfo:
>>>     Error ProcessLaunchInfo::GlobArguments(Target &target,
>>> ProcessLaunchInfo &new_launch_info);
>>> 2 - if eLaunchFlagGlobArguments is set, then call the new
>>> ProcessLaunchInfo::GlobArguments() function before doing any launches
>>> 3 - Add a Platform::GlobArguments() function that, for the current host,
>>> knows how to run the arg_dumper on the current host using the
>>> Host::GetDefaultShell().
>>> Then we need to figure out what to do for remote platforms. I am not
>>> sure we can guarantee there is an arg_dumper on the other side. For the
>>> lldb-platform, we could ensure that it has access to arg_dumper and can run
>>> it as a remote packet and return the results.
>>> Greg
>>> > On Feb 19, 2015, at 2:29 PM, Zachary Turner <zturner at google.com>
>>> wrote:
>>> >
>>> > Enrico, will your planned changes address the original issue?  Namely,
>>> that
>>> > if a process is launched through the process plugin with the
>>> > eLaunchFlagGlobArguments flag set, after your changes will the
>>> arguments
>>> > correctly go through the globber first?
>>> >
>>> >
>>> > http://reviews.llvm.org/D7743
>>> >
>>> >  http://reviews.llvm.org/settings/panel/emailpreferences/
>>> >
>>> >
>>> >
>>> > _______________________________________________
>>> > lldb-commits mailing list
>>> > lldb-commits at cs.uiuc.edu
>>> > http://lists.cs.uiuc.edu/mailman/listinfo/lldb-commits
> --
> Oleksiy Vyalov | Software Engineer | ovyalov at google.com
> _______________________________________________
> lldb-commits mailing list
> lldb-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-commits
> Thanks,
> *- Enrico*
> 📩 egranata@.com ☎️ 27683
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