Fallback to getpwuid() in path::home_directory() on Unix.

[chfast]

Refactor unit test helpers. Check if pwh.h is available in every place that requires it.

[chfast]

Gentle ping. This patch includes a small unit test helpers refactoring that I would like to use in other patches.

[• rafael]

Can you give an overview of when the HOME environment variable is not defined?

Cheers,
Rafael

[aaron.ballman]

lib/Support/Unix/Path.inc

558

Why 1024?

574

I'm not certain whether Dir is required here or not, but knowing its type would be good. We only use auto when the type is already spelled out, or when it's difficult to spell out (like some iterators).

584

Is getpwuid() more reliable than reading the environment variable?

[chfast]

In D14446#296010, @rafael wrote:

Can you give an overview of when the HOME environment variable is not defined?

E.g. in llvm-lit testing environment.

lib/Support/Unix/Path.inc

574

I will change that.

584

I don't understand the question. Are you asking which approach is better?

Checking the environmental variable first allows the user change home directory location visible by the application.

[chfast]

lib/Support/Unix/Path.inc

558

It is suggested initial buffer size returned by sysconf(_SC_GETPW_R_SIZE_MAX).

[aaron.ballman]

lib/Support/Unix/Path.inc

558

Ah, good to know, thank you!

584

I was under the impression (which may be incorrect) that getpwuid() was a safer, more reliable way to get the home directory, when the API is available, and the environment variable is more of a backup plan. If that is true, it would make sense to call getHomeDirFromPasswd() first, and fallback to getenv().

[• rafael]

E.g. in llvm-lit testing environment.

Isn't the intention precisely to avoid tests creating files in the
home directory or being dependent on global config entries?

Cheers,
Rafael

[chfast]

In D14446#296637, @rafael wrote:

E.g. in llvm-lit testing environment.

Isn't the intention precisely to avoid tests creating files in the
home directory or being dependent on global config entries?

Cheers,
Rafael

I'm not sure.

1. Temp directory does not fallback to $HOME.
2. Setting $HOME to "" might be a workaround.
3. On Windows Windows API is used to find out the user's home dir in case information from environment variables are not enough.

I don't really need this change, so if you believe it is an overkill, I'm happy to drop it.

[chfast]

Added authors/reviewers of original patch adding home_directory() function in http://reviews.llvm.org/D2199

Do you have any opinion about my patch? I don't insist on it to be merged.

cmake/config-ix.cmake

 check_include_file(limits.h HAVE_LIMITS_H)
 check_include_file(link.h HAVE_LINK_H)
 check_include_file(malloc.h HAVE_MALLOC_H)
 check_include_file(malloc/malloc.h HAVE_MALLOC_MALLOC_H)
 check_include_file(ndir.h HAVE_NDIR_H)
 if( NOT PURE_WINDOWS )
   check_include_file(pthread.h HAVE_PTHREAD_H)
 endif()
+check_include_file(pwd.h HAVE_PWD_H)
 check_include_file(signal.h HAVE_SIGNAL_H)
 check_include_file(stdint.h HAVE_STDINT_H)
 check_include_file(sys/dir.h HAVE_SYS_DIR_H)
 check_include_file(sys/ioctl.h HAVE_SYS_IOCTL_H)
 check_include_file(sys/mman.h HAVE_SYS_MMAN_H)
 check_include_file(sys/ndir.h HAVE_SYS_NDIR_H)
 check_include_file(sys/param.h HAVE_SYS_PARAM_H)
 check_include_file(sys/resource.h HAVE_SYS_RESOURCE_H)

include/llvm/Config/config.h.cmake

 #cmakedefine HAVE_PTHREAD_H ${HAVE_PTHREAD_H}
 
 /* Have pthread_mutex_lock */
 #cmakedefine HAVE_PTHREAD_MUTEX_LOCK ${HAVE_PTHREAD_MUTEX_LOCK}
 
 /* Have pthread_rwlock_init */
 #cmakedefine HAVE_PTHREAD_RWLOCK_INIT ${HAVE_PTHREAD_RWLOCK_INIT}
 
+/* Define to 1 if you have the <pwd.h> header file. */
+#cmakedefine HAVE_PWD_H ${HAVE_PWD_H}
+
 /* Define to 1 if srand48/lrand48/drand48 exist in <stdlib.h> */
 #cmakedefine HAVE_RAND48 ${HAVE_RAND48}
 
 /* Define to 1 if you have the `readdir' function. */
 #cmakedefine HAVE_READDIR ${HAVE_READDIR}
 
 /* Define to 1 if you have the `realpath' function. */
 #cmakedefine HAVE_REALPATH ${HAVE_REALPATH}

lib/Support/Unix/Path.inc

 #include <sys/stat.h>
 #endif
 #if HAVE_FCNTL_H
 #include <fcntl.h>
 #endif
 #ifdef HAVE_SYS_MMAN_H
 #include <sys/mman.h>
 #endif
+#ifdef HAVE_PWD_H
+#include <pwd.h>
+#endif
 #if HAVE_DIRENT_H
 # include <dirent.h>
 # define NAMLEN(dirent) strlen((dirent)->d_name)
 #else
 # define dirent direct
 # define NAMLEN(dirent) (dirent)->d_namlen
 # if HAVE_SYS_NDIR_H
 #  include <sys/ndir.h>
std::error_code openFileForWrite(const Twine &Name, int &ResultFD,
   }
   return std::error_code();
 }
 
 } // end namespace fs
 
 namespace path {
 
-bool home_directory(SmallVectorImpl<char> &result) {
+static bool getHomeDirFromPasswd(SmallVectorImpl<char> &Result) {
+#ifdef HAVE_PWD_H
+  static const size_t InitialBufSize = 1024;
+  SmallString<InitialBufSize> Buf;
+  Buf.reserve(InitialBufSize);
+  Buf.set_size(Buf.capacity());
+
+  ::passwd Passwd;
+  ::passwd *PasswdResult = nullptr;
+  int Err = 0;
+  while ((Err = ::getpwuid_r(::getuid(), &Passwd, Buf.data(), Buf.size(),
+                             &PasswdResult)) == ERANGE) {
+    Buf.reserve(Buf.size() * 2);
+    Buf.set_size(Buf.capacity());
+  }
+
+  if (!Err) {
+    assert(PasswdResult == &Passwd && "getpwuid_r does strange things");
+    auto Dir = Passwd.pw_dir;
+    Result.clear();
+    Result.append(Dir, Dir + strlen(Dir));
+    return true;
+  }
+#endif
+  return false;
+}
+
+bool home_directory(SmallVectorImpl<char> &Result) {
   if (char *RequestedDir = getenv("HOME")) {
-    result.clear();
-    result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
+    Result.clear();
+    Result.append(RequestedDir, RequestedDir + strlen(RequestedDir));
     return true;
   }
 
+  if (getHomeDirFromPasswd(Result))
+    return true;
+
   return false;
 }
 
 static bool getDarwinConfDir(bool TempDir, SmallVectorImpl<char> &Result) {
   #if defined(_CS_DARWIN_USER_TEMP_DIR) && defined(_CS_DARWIN_USER_CACHE_DIR)
   // On Darwin, use DARWIN_USER_TEMP_DIR or DARWIN_USER_CACHE_DIR.
   // macros defined in <unistd.h> on darwin >= 9
   int ConfName = TempDir ? _CS_DARWIN_USER_TEMP_DIR

unittests/Support/Path.cpp

#endif
   if (!expected.empty()) {
     SmallString<128> HomeDir;
     auto status = path::home_directory(HomeDir);
     EXPECT_TRUE(status);
     EXPECT_EQ(expected, HomeDir);
   }
 }
 
+static std::string path2regex(std::string Path) {
+  size_t Pos = 0;
+  while ((Pos = Path.find('\\', Pos)) != std::string::npos) {
+    Path.replace(Pos, 1, "\\\\");
+    Pos += 2;
+  }
+  return Path;
+}
+
+/// Helper for running known dir test that depends on enviroment variables in
+/// separated process. This allows checking different values of enviroment
+/// variables without messing up the environment of the current process.
+#define EXPECT_DIR(test, expected)                                             \
+  EXPECT_EXIT(                                                                 \
+      {                                                                        \
+        SmallString<300> Dir;                                                  \
+        test;                                                                  \
+        raw_os_ostream(std::cerr) << Dir;                                      \
+        std::exit(0);                                                          \
+      },                                                                       \
+      ::testing::ExitedWithCode(0), path2regex(expected))
+
+/// Helper for running home dir test in separated process, @see EXPECT_DIR.
+#define EXPECT_HOME_DIR(prepare, expected)                                     \
+  EXPECT_DIR(                                                                  \
+      {                                                                        \
+        prepare;                                                               \
+        path::home_directory(Dir);                                             \
+      },                                                                       \
+      expected)
+
+/// Helper for running temp dir test in separated process, @see EXPECT_DIR.
+#define EXPECT_TEMP_DIR(prepare, expected)                                     \
+  EXPECT_DIR(                                                                  \
+      {                                                                        \
+        prepare;                                                               \
+        path::system_temp_directory(true, Dir);                                \
+      },                                                                       \
+      expected)
+
+#ifdef LLVM_ON_UNIX
+TEST(SupportDeathTest, HomeDirectoryOnUnix) {
+  EXPECT_HOME_DIR(setenv("HOME", "/home/LLVMUser", true), "/home/LLVMUser");
+}
+#endif
+
 TEST(Support, UserCacheDirectory) {
   SmallString<13> CacheDir;
   SmallString<20> CacheDir2;
   auto Status = path::user_cache_directory(CacheDir, "");
   EXPECT_TRUE(Status ^ CacheDir.empty());
 
   if (Status) {
     EXPECT_TRUE(path::user_cache_directory(CacheDir2, "")); // should succeed
TEST(Support, TempDirectory) {
   SmallString<32> TempDir;
   path::system_temp_directory(false, TempDir);
   EXPECT_TRUE(!TempDir.empty());
   TempDir.clear();
   path::system_temp_directory(true, TempDir);
   EXPECT_TRUE(!TempDir.empty());
 }
 
-#ifdef LLVM_ON_WIN32
-static std::string path2regex(std::string Path) {
-  size_t Pos = 0;
-  while ((Pos = Path.find('\\', Pos)) != std::string::npos) {
-    Path.replace(Pos, 1, "\\\\");
-    Pos += 2;
-  }
-  return Path;
+#ifdef LLVM_ON_UNIX
+TEST(SupportDeathTest, TempDirectoryOnUnix) {
+  EXPECT_TEMP_DIR(setenv("TMPDIR", "/home/LLVMUser/.tmp", true),
+                  "/home/LLVMUser/.tmp");
 }
+#endif
 
-/// Helper for running temp dir test in separated process. See below.
-#define EXPECT_TEMP_DIR(prepare, expected)                                     \
-  EXPECT_EXIT(                                                                 \
-      {                                                                        \
-        prepare;                                                               \
-        SmallString<300> TempDir;                                              \
-        path::system_temp_directory(true, TempDir);                            \
-        raw_os_ostream(std::cerr) << TempDir;                                  \
-        std::exit(0);                                                          \
-      },                                                                       \
-      ::testing::ExitedWithCode(0), path2regex(expected))
-
+#ifdef LLVM_ON_WIN32
 TEST(SupportDeathTest, TempDirectoryOnWindows) {
   // In this test we want to check how system_temp_directory responds to
   // different values of specific env vars. To prevent corrupting env vars of
   // the current process all checks are done in separated processes.
   EXPECT_TEMP_DIR(_wputenv_s(L"TMP", L"C:\\OtherFolder"), "C:\\OtherFolder");
   EXPECT_TEMP_DIR(_wputenv_s(L"TMP", L"C:/Unix/Path/Seperators"),
                   "C:\\Unix\\Path\\Seperators");
   EXPECT_TEMP_DIR(_wputenv_s(L"TMP", L"Local Path"), ".+\\Local Path$");