[Lldb-commits] Bug 16443 - target create doesn't expand ~ on Linux

[Matthew Sorrels]

Any comments on this?


On Wed, Jun 26, 2013 at 3:41 PM, Matthew Sorrels <sorrels.m at gmail.com>wrote:

> This changes TargetList so that it will expand the ~ cases, but not
> process any symbolic links while doing so.  It does this by using the
> FileSpec::ResolveUsername function directly.  It seems to work on cases
> where the binary is something like ~/a.out it also works on cases where the
> binary is a symbolic link ~/mytest the arg0 passed in is mytest and not
> a.out.
>
> Index: source/Target/TargetList.cpp
> ===================================================================
> --- source/Target/TargetList.cpp    (revision 185025)
> +++ source/Target/TargetList.cpp    (working copy)
> @@ -221,8 +221,19 @@
>
>      FileSpec file (user_exe_path, false);
>      if (!file.Exists() && user_exe_path && user_exe_path[0] == '~')
>      {
> -        file = FileSpec(user_exe_path, true);
> +        // we want to expand the tilde but we don't want to resolve any
> symbolic links
> +        // so we can't use the FileSpec constructor's resolve flag
> +        char unglobbed_path[PATH_MAX];
> +        unglobbed_path[0] = '\0';
> +
> +        size_t return_count = FileSpec::ResolveUsername(user_exe_path,
> unglobbed_path, sizeof(unglobbed_path));
> +
> +        if (return_count == 0 || return_count >= sizeof(unglobbed_path))
> +            ::snprintf (unglobbed_path, sizeof(unglobbed_path), "%s",
> user_exe_path);
> +
> +        file = FileSpec(unglobbed_path, false);
>      }
> +
>      bool user_exe_path_is_bundle = false;
>      char resolved_bundle_exe_path[PATH_MAX];
>      resolved_bundle_exe_path[0] = '\0';
> @@ -304,8 +315,8 @@
>
>              }
>              else
>              {
> -                // Just use what the user typed
> -                target_sp->SetArg0 (user_exe_path);
> +                // Use resolved path
> +                target_sp->SetArg0 (file.GetPath().c_str());
>              }
>          }
>          if (file.GetDirectory())
>
>
>
> On Tue, Jun 25, 2013 at 1:47 PM, Greg Clayton <gclayton at apple.com> wrote:
>
>> This patch will break people who try and do the following:
>>
>> % lldb /usr/bin/clang++
>>
>> clang++ is a symlink to "/usr/bin/clang". When we debug the program and
>> it reaches main, clang will look at argv[0] and do something if the program
>> is clang++ and something else if it is clang. We really want to _just_
>> resolve the "~" or the "~username" from the path and leave the rest alone
>> so we don't change argv[0] from what the user specified.
>>
>> On Jun 25, 2013, at 1:29 PM, Matthew Sorrels <sorrels.m at gmail.com> wrote:
>>
>> > Bug 16443 - target create doesn't expand ~ on Linux
>> >
>> > I created a bug for this, but it wasn't as complex to fix as I had
>> thought.  Though I'm not exactly sure what the effects this change could
>> have.  The test suite runs the same on Linux with or without it, but I'm
>> not sure that's enough.  It does seem like the code went out of its way to
>> set the arg0 to be whatever the user typed, rather than the resolved path.
>>  Perhaps there is a reason for this I don't understand?
>> >
>> >
>> > Here's the bug summary:
>> > If you start lldb and do a target create on a path with a ~ as part of
>> the path, it is accepted but when trying to run the process the launch
>> fails.
>> >
>> > Here's an example where the test binary is ~/a.out  it is also
>> /home/matthews/a.out which works fine.  Both paths work fine when used on
>> the command line (most likely due to shell expansion)
>> >
>> > matthews at matthews-linux:~/work/llvm/llvm/build$ bin/lldb
>> > (lldb) version
>> > lldb version 3.4 (
>> > http://llvm.org/svn/llvm-project/lldb/trunk
>> >  revision 184861)
>> > (lldb) target create ~/a.out
>> > Current executable set to '~/a.out' (x86_64).
>> > (lldb) run
>> > error: process launch failed: Child exec failed.
>> >
>> >
>> > (lldb) target create /home/matthews/a.out
>> > Current executable set to '/home/matthews/a.out' (x86_64).
>> > (lldb) run
>> > Process 4493 launched: '/home/matthews/a.out' (x86_64)
>> > Hello world!
>> > Function 106
>> > Process 4493 exited with status = 13 (0x0000000d)
>> > (lldb)
>> >
>> > The target list command shows the full path to the file, but that full
>> path isn't being used when the process is started with run.
>> >
>> > (lldb) target create ~/a.out
>> > Current executable set to '~/a.out' (x86_64).
>> > (lldb) target list
>> > Current targets:
>> > * target #0: /home/matthews/a.out ( arch=x86_64--linux,
>> platform=localhost )
>> >
>> >
>> > Here's a possible patch:
>> >
>> > Index: source/Target/TargetList.cpp
>> > ===================================================================
>> > --- source/Target/TargetList.cpp    (revision 184861)
>> > +++ source/Target/TargetList.cpp    (working copy)
>> > @@ -304,8 +304,8 @@
>> >              }
>> >              else
>> >              {
>> > -                // Just use what the user typed
>> > -                target_sp->SetArg0 (user_exe_path);
>> > +                // Use resolved path
>> > +                target_sp->SetArg0 (file.GetPath().c_str());
>> >              }
>> >          }
>> >          if (file.GetDirectory())
>> >
>> > _______________________________________________
>> > lldb-commits mailing list
>> > lldb-commits at cs.uiuc.edu
>> > http://lists.cs.uiuc.edu/mailman/listinfo/lldb-commits
>>
>>
>
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