Improve PID file error and datadir handling

src/init.cpp

@@ -70,6 +70,8 @@
 #include <memory>
 
 #ifndef WIN32
+#include <attributes.h>
+#include <cerrno>
 #include <signal.h>
 #include <sys/stat.h>
 #endif
@@ -114,6 +116,29 @@ static const char* DEFAULT_ASMAP_FILENAME="ip_asn.map";
 static const char* FEE_ESTIMATES_FILENAME = "fee_estimates.dat";
 CClientUIInterface uiInterface;  // Declared but not defined in guiinterface.h
 
+/**
+ * The PID file facilities.
+ */
+const char * const PIVX_PID_FILENAME = "pivx.pid";
+
+fs::path GetPidFile()
+{
+    fs::path pathPidFile(gArgs.GetArg("-pid", PIVX_PID_FILENAME));
+    return AbsPathForConfigVal(pathPidFile);
+}
+
+NODISCARD static bool CreatePidFile()
+{
+    FILE* file = fsbridge::fopen(GetPidFile(), "w");
+    if (file) {
+        fprintf(file, "%d\n", getpid());
+        fclose(file);
+        return true;
+    } else {
+        return UIError(strprintf(_("Unable to create the PID file '%s': %s"), GetPidFile().string(), std::strerror(errno)));
+    }
+}
+
 //////////////////////////////////////////////////////////////////////////////
 //
 // Shutdown
@@ -309,7 +334,7 @@ void Shutdown()
             LogPrintf("%s: Unable to remove PID file: File does not exist\n", __func__);
         }
     } catch (const fs::filesystem_error& e) {
-        LogPrintf("%s: Unable to remove pidfile: %s\n", __func__, e.what());
+        LogPrintf("%s: Unable to remove PID file: %s\n", __func__, e.what());
     }
 #endif
 
@@ -1168,7 +1193,10 @@ bool AppInitMain()
     }
 
 #ifndef WIN32
-    CreatePidFile(GetPidFile(), getpid());
+    if (!CreatePidFile()) {
+        // Detailed error printed inside CreatePidFile().
+        return false;
+    }
 #endif
     if (g_logger->m_print_to_file) {
         if (gArgs.GetBoolArg("-shrinkdebugfile", g_logger->DefaultShrinkDebugFile()))

src/pivx-cli.cpp

@@ -101,7 +101,7 @@ static bool AppInitRPC(int argc, char* argv[])
         fprintf(stdout, "%s", strUsage.c_str());
         return false;
     }
-    if (!fs::is_directory(GetDataDir(false))) {
+    if (!CheckDataDirOption()) {
         fprintf(stderr, "Error: Specified data directory \"%s\" does not exist.\n", gArgs.GetArg("-datadir", "").c_str());
         return false;
     }

src/pivxd.cpp

@@ -74,7 +74,7 @@ bool AppInit(int argc, char* argv[])
     }
 
     try {
-        if (!fs::is_directory(GetDataDir(false))) {
+        if (!CheckDataDirOption()) {
             fprintf(stderr, "Error: Specified data directory \"%s\" does not exist.\n", gArgs.GetArg("-datadir", "").c_str());
             return false;
         }

src/qt/pivx.cpp

@@ -613,9 +613,9 @@ int main(int argc, char* argv[])
     if (!Intro::pickDataDirectory())
         return 0;
 
-    /// 6. Determine availability of data and blocks directory and parse pivx.conf
+    /// 6. Determine availability of data directory and parse pivx.conf
     /// - Do not call GetDataDir(true) before this step finishes
-    if (!fs::is_directory(GetDataDir(false))) {
+    if (!CheckDataDirOption()) {
         QMessageBox::critical(nullptr, PACKAGE_NAME,
             QObject::tr("Error: Specified data directory \"%1\" does not exist.").arg(QString::fromStdString(gArgs.GetArg("-datadir", ""))));
         return 1;

src/util/system.cpp

@@ -79,7 +79,6 @@
 #endif
 
 const char * const PIVX_CONF_FILENAME = "pivx.conf";
-const char * const PIVX_PID_FILENAME = "pivx.pid";
 const char * const PIVX_MASTERNODE_CONF_FILENAME = "masternode.conf";
 
 
@@ -730,11 +729,11 @@ const fs::path& GetDataDir(bool fNetSpecific)
 
     // This can be called during exceptions by LogPrintf(), so we cache the
     // value so we don't have to do memory allocations after that.
-    if (!path.empty())
-        return path;
+    if (!path.empty()) return path;
 
-    if (gArgs.IsArgSet("-datadir")) {
-        path = fs::system_complete(gArgs.GetArg("-datadir", ""));
+    std::string datadir = gArgs.GetArg("-datadir", "");
+    if (!datadir.empty()) {
+        path = fs::system_complete(datadir);
         if (!fs::is_directory(path)) {
             path = "";
             return path;
@@ -753,6 +752,12 @@ const fs::path& GetDataDir(bool fNetSpecific)
     return path;
 }
 
+bool CheckDataDirOption()
+{
+    std::string datadir = gArgs.GetArg("-datadir", "");
+    return datadir.empty() || fs::is_directory(fs::system_complete(datadir));
+}
+
 void ClearDatadirCache()
 {
     LOCK(csPathCached);
@@ -840,7 +845,7 @@ void ArgsManager::ReadConfigFile(const std::string& confPath)
 
     // If datadir is changed in .conf file:
     ClearDatadirCache();
-    if (!fs::is_directory(GetDataDir(false))) {
+    if (!CheckDataDirOption()) {
         throw std::runtime_error(strprintf("specified data directory \"%s\" does not exist.", gArgs.GetArg("-datadir", "").c_str()));
     }
 }
@@ -867,23 +872,6 @@ std::string ArgsManager::GetChainName() const
     return CBaseChainParams::MAIN;
 }
 
-#ifndef WIN32
-fs::path GetPidFile()
-{
-    fs::path pathPidFile(gArgs.GetArg("-pid", PIVX_PID_FILENAME));
-    return AbsPathForConfigVal(pathPidFile);
-}
-
-void CreatePidFile(const fs::path& path, pid_t pid)
-{
-    FILE* file = fsbridge::fopen(path, "w");
-    if (file) {
-        fprintf(file, "%d\n", pid);
-        fclose(file);
-    }
-}
-#endif
-
 bool RenameOver(fs::path src, fs::path dest)
 {
 #ifdef WIN32

src/util/system.h

@@ -100,17 +100,15 @@ fs::path GetDefaultDataDir();
 // The blocks directory is always net specific.
 const fs::path &GetBlocksDir();
 const fs::path &GetDataDir(bool fNetSpecific = true);
+// Return true if -datadir option points to a valid directory or is not specified.
+bool CheckDataDirOption();
 // Sapling network dir
 const fs::path &ZC_GetParamsDir();
 // Init sapling library
 void initZKSNARKS();
 void ClearDatadirCache();
 fs::path GetConfigFile(const std::string& confPath);
 fs::path GetMasternodeConfigFile();
-#ifndef WIN32
-fs::path GetPidFile();
-void CreatePidFile(const fs::path& path, pid_t pid);
-#endif
 #ifdef WIN32
 fs::path GetSpecialFolderPath(int nFolder, bool fCreate = true);
 #endif