Allow state directory based in $HOME.

CMakeLists.txt

@@ -160,6 +160,11 @@ if(NOT WIN32)
     target.  Disabling this is useful in the case where the CMAKE_INSTALL_PREFIX
     is owned by a non-privileged user but where the WATCHMAN_STATE_DIR requires
     administrative rights to create and set its permissions.")
+  option(WATCHMAN_USE_XDG_STATE_HOME
+    "If enabled, use $XDG_STATE_HOME/watchman as the Watchman state directory. \
+    XDG_STATE_HOME defaults to $HOME/.local/state."
+    OFF
+  )
 else()
   set(WATCHMAN_STATE_DIR)
   set(INSTALL_WATCHMAN_STATE_DIR)
@@ -189,6 +194,9 @@ if(BUILD_INFO)
   config_h("#define WATCHMAN_BUILD_INFO \"${BUILD_INFO}\"")
 endif ()
 
+if(WATCHMAN_USE_XDG_STATE_HOME)
+  config_h("#define WATCHMAN_USE_XDG_STATE_HOME 1")
+endif()
 
 # While most of these tests are not strictly needed on windows, it is vital
 # that we probe for and find strtoll in order for the jansson build to use

watchman/UserDir.cpp

@@ -9,6 +9,8 @@
 #include <eden/common/utils/StringConv.h>
 #include <fmt/core.h>
 #include <folly/String.h>
+#include <pwd.h>
+#include <unistd.h>
 #include "watchman/Logging.h"
 #include "watchman/Options.h"
 #include "watchman/fs/FileSystem.h"
@@ -131,11 +133,52 @@ std::string computeUserName() {
   throw std::logic_error("unreachable");
 }
 
+std::string computeHomeDirectory() {
+    const char* homeDir = getenv("HOME");
+
+    if (!homeDir || *homeDir == 0) {
+        uid_t uid = getuid();
+        struct passwd* pw = getpwuid(uid);
+
+        if (!pw) {
+            log(FATAL,
+                "getpwuid(",
+                uid,
+                ") failed: ",
+                folly::errnoStr(errno),
+                ".  I don't know who you are\n");
+        }
+        homeDir = pw->pw_dir;
+    }
+
+    return homeDir;
+}
+
+const std::string& getHomeDirectory() {
+    static std::string homeDir = computeHomeDirectory();
+    return homeDir;
+}
+
 const std::string& getTemporaryDirectory() {
   static std::string tmpdir = computeTemporaryDirectory();
   return tmpdir;
 }
 
+std::string computeXDGStateHomeDirectory() {
+    char* xdgStateHome = getenv("XDG_STATE_HOME");
+
+    if (!xdgStateHome || *xdgStateHome == 0) {
+        return fmt::format("{}/.local/state", getHomeDirectory());
+    }
+
+    return xdgStateHome;
+}
+
+const std::string& getXDGStateHomeDirectory() {
+    static std::string xdgStateHome = computeXDGStateHomeDirectory();
+    return xdgStateHome;
+}
+
 std::string computeWatchmanStateDirectory(const std::string& user) {
   if (!flags.test_state_dir.empty()) {
     return fmt::format("{}/{}-state", flags.test_state_dir, user);
@@ -145,7 +188,9 @@ std::string computeWatchmanStateDirectory(const std::string& user) {
   return getCachedWatchmanAppDataPath();
 #else
   auto state_parent =
-#ifdef WATCHMAN_STATE_DIR
+#if defined(WATCHMAN_USE_XDG_STATE_HOME)
+      fmt::format("{}/watchman", getXDGStateHomeDirectory())
+#elif defined(WATCHMAN_STATE_DIR)
       WATCHMAN_STATE_DIR
 #else
       getTemporaryDirectory().c_str()

watchman/UserDir.h

@@ -21,9 +21,13 @@ std::string computeUserName();
  */
 const std::string& getTemporaryDirectory();
 
+/**
+ * Returns a cached reference to the current user's home directory.
+ */
+const std::string& getHomeDirectory();
+
 /**
  * Computes the Watchman state directory corresponding to the given user name.
  */
 std::string computeWatchmanStateDirectory(const std::string& user);
-
 } // namespace watchman

watchman/main.cpp

@@ -473,36 +473,23 @@ static SpawnResult spawn_via_launchd() {
   uint32_t size = sizeof(watchman_path);
   char plist_path[WATCHMAN_NAME_MAX];
   FILE* fp;
-  struct passwd* pw;
-  uid_t uid;
 
   close_random_fds();
 
   if (_NSGetExecutablePath(watchman_path, &size) == -1) {
     log(FATAL, "_NSGetExecutablePath: path too long; size ", size, "\n");
   }
 
-  uid = getuid();
-  pw = getpwuid(uid);
-  if (!pw) {
-    log(FATAL,
-        "getpwuid(",
-        uid,
-        ") failed: ",
-        folly::errnoStr(errno),
-        ".  I don't know who you are\n");
-  }
-
   snprintf(
-      plist_path, sizeof(plist_path), "%s/Library/LaunchAgents", pw->pw_dir);
+      plist_path, sizeof(plist_path), "%s/Library/LaunchAgents", getHomeDirectory().c_str());
   // Best effort attempt to ensure that the agents dir exists.  We'll detect
   // and report the failure in the fopen call below.
   mkdir(plist_path, 0755);
   snprintf(
       plist_path,
       sizeof(plist_path),
       "%s/Library/LaunchAgents/com.github.facebook.watchman.plist",
-      pw->pw_dir);
+      getHomeDirectory().c_str());
 
   if (access(plist_path, R_OK) == 0) {
     // Unload any that may already exist, as it is likely wrong