llvm dev - Apr 2016 - llvm::sys::path::home_directory() implementation for unix

I recently was using llvm code from a process that I manually spawned as a child
process and noticed that llvm::sys::path::home_directory() only works if
"HOME" is set in the process environment:

bool home_directory(SmallVectorImpl<char> &result) {
  if (char *RequestedDir = getenv("HOME")) {
    result.clear();
    result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
    return true;
  }

  return false;
}

This is in lib/Support/Unix/Path.inc. Do we want to try a little bit harder?
Maybe something like:

bool home_directory(SmallVectorImpl<char> &result) {
  if (char *RequestedDir = getenv("HOME")) {
    result.clear();
    result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
    return true;
  } else {
    struct passwd *pw = getpwuid(getuid());
    if (pw && pw->pw_dir && pw->pw_dir[0])
    {
      setenv("HOME", pw->pw_dir, 0);
      result.assign(llvm::StringRef(pw->pw_dir));
      return true;
    }
  }
  return false;
}

We probably don't want to silently mutate the environment (which could lead
to surprises), but calling a proper system library function to get the home
directory makes sense.

-- Sean Silva

On Tue, Apr 19, 2016 at 11:18 AM, Greg Clayton via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> I recently was using llvm code from a process that I manually spawned as a
> child process and noticed that llvm::sys::path::home_directory() only works
> if "HOME" is set in the process environment:
>
> bool home_directory(SmallVectorImpl<char> &result) {
>   if (char *RequestedDir = getenv("HOME")) {
>     result.clear();
>     result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
>     return true;
>   }
>
>   return false;
> }
>
> This is in lib/Support/Unix/Path.inc. Do we want to try a little bit
> harder? Maybe something like:
>
> bool home_directory(SmallVectorImpl<char> &result) {
>   if (char *RequestedDir = getenv("HOME")) {
>     result.clear();
>     result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
>     return true;
>   } else {
>     struct passwd *pw = getpwuid(getuid());
>     if (pw && pw->pw_dir && pw->pw_dir[0])
>     {
>       setenv("HOME", pw->pw_dir, 0);
>       result.assign(llvm::StringRef(pw->pw_dir));
>       return true;
>     }
>   }
>   return false;
> }
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20160419/e1ba512f/attachment.html>

Hi there,

The issue has been discussed before, in case of this patch
http://reviews.llvm.org/D14446.

Some see this issue as a feature to disable access to home directory.

I'm happy to implement whatever we agree on.

- Paweł

On Wed, Apr 20, 2016 at 8:51 AM Sean Silva via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> We probably don't want to silently mutate the environment (which could
> lead to surprises), but calling a proper system library function to get the
> home directory makes sense.
>
> -- Sean Silva
>
> On Tue, Apr 19, 2016 at 11:18 AM, Greg Clayton via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> I recently was using llvm code from a process that I manually spawned
as
>> a child process and noticed that llvm::sys::path::home_directory() only
>> works if "HOME" is set in the process environment:
>>
>> bool home_directory(SmallVectorImpl<char> &result) {
>>   if (char *RequestedDir = getenv("HOME")) {
>>     result.clear();
>>     result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
>>     return true;
>>   }
>>
>>   return false;
>> }
>>
>> This is in lib/Support/Unix/Path.inc. Do we want to try a little bit
>> harder? Maybe something like:
>>
>> bool home_directory(SmallVectorImpl<char> &result) {
>>   if (char *RequestedDir = getenv("HOME")) {
>>     result.clear();
>>     result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
>>     return true;
>>   } else {
>>     struct passwd *pw = getpwuid(getuid());
>>     if (pw && pw->pw_dir && pw->pw_dir[0])
>>     {
>>       setenv("HOME", pw->pw_dir, 0);
>>       result.assign(llvm::StringRef(pw->pw_dir));
>>       return true;
>>     }
>>   }
>>   return false;
>> }
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20160420/c7981236/attachment.html>