[llvm] r298513 - Make home_directory look in the password database in addition to $HOME.

[Stephan Bergmann via llvm-commits]

On 03/22/2017 04:24 PM, Zachary Turner via llvm-commits wrote:
> Author: zturner
> Date: Wed Mar 22 10:24:59 2017
> New Revision: 298513
>
> URL: http://llvm.org/viewvc/llvm-project?rev=298513&view=rev
> Log:
> Make home_directory look in the password database in addition to $HOME.
>
> This is something of an edge case, but when the $HOME environment
> variable is not set, we can still look in the password database
> to get the current user's home directory.
>
> Added a test for this by getting the value of $HOME, then unsetting
> it, then calling home_directory() and verifying that it succeeds
> and that the value is the same as what we originally read from
> the environment.

Why should builds not be supported which are done in an environment 
where HOME deliberately points somewhere other than the user's home 
directory?

> Modified:
>     llvm/trunk/lib/Support/Unix/Path.inc
>     llvm/trunk/unittests/Support/Path.cpp
>
> Modified: llvm/trunk/lib/Support/Unix/Path.inc
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Unix/Path.inc?rev=298513&r1=298512&r2=298513&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Support/Unix/Path.inc (original)
> +++ llvm/trunk/lib/Support/Unix/Path.inc Wed Mar 22 10:24:59 2017
> @@ -920,12 +920,18 @@ std::error_code real_path(const Twine &p
>  namespace path {
>
>  bool home_directory(SmallVectorImpl<char> &result) {
> -  if (char *RequestedDir = getenv("HOME")) {
> -    result.clear();
> -    result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
> -    return true;
> +  char *RequestedDir = getenv("HOME");
> +  if (!RequestedDir) {
> +    struct passwd *pw = getpwuid(getuid());
> +    if (pw && pw->pw_dir)
> +      RequestedDir = pw->pw_dir;
>    }
> -  return false;
> +  if (!RequestedDir)
> +    return false;
> +
> +  result.clear();
> +  result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
> +  return true;
>  }
>
>  static bool getDarwinConfDir(bool TempDir, SmallVectorImpl<char> &Result) {
>
> Modified: llvm/trunk/unittests/Support/Path.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/Path.cpp?rev=298513&r1=298512&r2=298513&view=diff
> ==============================================================================
> --- llvm/trunk/unittests/Support/Path.cpp (original)
> +++ llvm/trunk/unittests/Support/Path.cpp Wed Mar 22 10:24:59 2017
> @@ -328,6 +328,26 @@ TEST(Support, HomeDirectory) {
>    }
>  }
>
> +#ifndef LLVM_ON_WIN32
> +TEST(Support, HomeDirectoryWithNoEnv) {
> +  std::string Original;
> +  char const *path = ::getenv("HOME");
> +  // Don't try to test if we don't have something to compare against.
> +  if (!path)
> +    return;
> +  Original = path;
> +  ::unsetenv("HOME");
> +
> +  SmallString<128> HomeDir;
> +  auto status = path::home_directory(HomeDir);
> +  EXPECT_TRUE(status);
> +  EXPECT_EQ(Original, HomeDir);
> +
> +  // Now put the original environment variable back
> +  ::setenv("HOME", Original.c_str(), 1);
> +}
> +#endif
> +
>  TEST(Support, UserCacheDirectory) {
>    SmallString<13> CacheDir;
>    SmallString<20> CacheDir2;