[Lldb-commits] [lldb] r248048 - Added support for resolving symbolic links to FileSpec.

[Zachary Turner via lldb-commits]

Hi Sean, I was digging around in FileSystem.h and I noticed we already have
`FileSystem::Readlink`.  Reading the documentation of `readlink` and
`realpath` there seem to be a few minor differences, but they are just that
- minor.  I'm wondering if you actually *need* any semantics of `realpath`
that `readlink` don't provide.  If not, maybe we can delete
`FileSystem::ResolveSymbolicLink` and use `FileSystem::Readlink` instead.
What do you think?
On Fri, Sep 18, 2015 at 2:42 PM Zachary Turner <zturner at google.com> wrote:

> Any time there's something involving windows, even if you're just
> #ifdef'ing out a code path, I would prefer if you could wait until I or
> someone else who works on Windows has a chance to comment before committing.
>
> On Fri, Sep 18, 2015 at 2:40 PM Sean Callanan via lldb-commits <
> lldb-commits at lists.llvm.org> wrote:
>
>> Author: spyffe
>> Date: Fri Sep 18 16:39:31 2015
>> New Revision: 248048
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=248048&view=rev
>> Log:
>> Added support for resolving symbolic links to FileSpec.
>>
>> We use the symbolic link to resolver to find the target of the LLDB shlib
>> symlink if there is a symlink.  This allows us to find shlib-relative
>> resources
>> even when running under the testsuite, where _lldb.so is a symlink in the
>> Python
>> resource directory.
>>
>> Also changed a comment to be slightly more clear about what resolve_path
>> in the
>> constructor for FileSpec means, since if we were actually using
>> realpath() this
>> code wouldn't have been necessary.
>>
>> http://reviews.llvm.org/D12984
>>
>> Modified:
>>     lldb/trunk/include/lldb/Host/FileSpec.h
>>     lldb/trunk/source/Host/common/FileSpec.cpp
>>     lldb/trunk/source/Host/common/HostInfoBase.cpp
>>
>> Modified: lldb/trunk/include/lldb/Host/FileSpec.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/lldb/trunk/include/lldb/Host/FileSpec.h?rev=248048&r1=248047&r2=248048&view=diff
>>
>> ==============================================================================
>> --- lldb/trunk/include/lldb/Host/FileSpec.h (original)
>> +++ lldb/trunk/include/lldb/Host/FileSpec.h Fri Sep 18 16:39:31 2015
>> @@ -73,7 +73,7 @@ public:
>>      ///     The full or partial path to a file.
>>      ///
>>      /// @param[in] resolve_path
>> -    ///     If \b true, then we resolve the path with realpath,
>> +    ///     If \b true, then we resolve the path, removing stray ../..
>> and so forth,
>>      ///     if \b false we trust the path is in canonical form already.
>>      ///
>>      /// @see FileSpec::SetFile (const char *path, bool resolve)
>> @@ -511,6 +511,9 @@ public:
>>
>>      bool
>>      IsSymbolicLink () const;
>> +
>> +    FileSpec
>> +    ResolveSymbolicLink () const;
>>
>>      //------------------------------------------------------------------
>>      /// Get the memory cost of this object.
>>
>> Modified: lldb/trunk/source/Host/common/FileSpec.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Host/common/FileSpec.cpp?rev=248048&r1=248047&r2=248048&view=diff
>>
>> ==============================================================================
>> --- lldb/trunk/source/Host/common/FileSpec.cpp (original)
>> +++ lldb/trunk/source/Host/common/FileSpec.cpp Fri Sep 18 16:39:31 2015
>> @@ -811,6 +811,32 @@ FileSpec::IsSymbolicLink () const
>>  #endif
>>  }
>>
>> +FileSpec
>> +FileSpec::ResolveSymbolicLink () const {
>> +    if (!IsSymbolicLink())
>> +    {
>> +        return *this;
>> +    }
>> +
>> +    char resolved_path[PATH_MAX];
>> +    if (!GetPath (resolved_path, sizeof (resolved_path)))
>> +    {
>> +        return *this;
>> +    }
>> +
>> +#ifdef _WIN32
>> +    return *this; // TODO make this work on win32
>> +#else
>> +    char real_path[PATH_MAX + 1];
>> +    if (realpath(resolved_path, real_path) == nullptr)
>> +    {
>> +        return *this;
>> +    }
>> +
>> +    return FileSpec(real_path, false);
>> +#endif
>> +}
>> +
>>  uint32_t
>>  FileSpec::GetPermissions () const
>>  {
>>
>> Modified: lldb/trunk/source/Host/common/HostInfoBase.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Host/common/HostInfoBase.cpp?rev=248048&r1=248047&r2=248048&view=diff
>>
>> ==============================================================================
>> --- lldb/trunk/source/Host/common/HostInfoBase.cpp (original)
>> +++ lldb/trunk/source/Host/common/HostInfoBase.cpp Fri Sep 18 16:39:31
>> 2015
>> @@ -306,7 +306,10 @@ HostInfoBase::ComputeSharedLibraryDirect
>>
>>      FileSpec lldb_file_spec(
>>          Host::GetModuleFileSpecForHostAddress(reinterpret_cast<void
>> *>(reinterpret_cast<intptr_t>(HostInfoBase::GetLLDBPath))));
>> -
>> +
>> +    // This is necessary because when running the testsuite the shlib
>> might be a symbolic link inside the Python resource dir.
>> +    lldb_file_spec = lldb_file_spec.ResolveSymbolicLink();
>> +
>>      // Remove the filename so that this FileSpec only represents the
>> directory.
>>      file_spec.GetDirectory() = lldb_file_spec.GetDirectory();
>>
>>
>>
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