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

[Matthew Sorrels]

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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