Provide relevant error message if datadir is not writable.

murrayn · furszy · commit 48349f8cb465 · 2021-08-01T11:55:51.000-03:00
diff --git a/src/init.cpp b/src/init.cpp
@@ -1190,6 +1190,9 @@ static bool LockDataDirectory(bool probeOnly)
 {
     // Make sure only a single PIVX process is using the data directory.
     fs::path datadir = GetDataDir();
+    if (!DirIsWritable(datadir)) {
+        return UIError(strprintf(_("Cannot write to data directory '%s'; check permissions."), datadir.string()));
+    }
     if (!LockDirectory(datadir, ".lock", probeOnly)) {
         return UIError(strprintf(_("Cannot obtain a lock on data directory %s. %s is probably already running."), datadir.string(), _(PACKAGE_NAME)));
     }
diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp
@@ -1093,6 +1093,22 @@ BOOST_AUTO_TEST_CASE(test_LockDirectory)
     fs::remove_all(dirname);
 }
 
+BOOST_AUTO_TEST_CASE(test_DirIsWritable)
+{
+    // Should be able to write to the system tmp dir.
+    fs::path tmpdirname = fs::temp_directory_path();
+    BOOST_CHECK_EQUAL(DirIsWritable(tmpdirname), true);
+
+    // Should not be able to write to a non-existent dir.
+    tmpdirname = fs::temp_directory_path() / fs::unique_path();
+    BOOST_CHECK_EQUAL(DirIsWritable(tmpdirname), false);
+
+    fs::create_directory(tmpdirname);
+    // Should be able to write to it now.
+    BOOST_CHECK_EQUAL(DirIsWritable(tmpdirname), true);
+    fs::remove(tmpdirname);
+}
+
 namespace {
 
     struct Tracker
diff --git a/src/util/system.cpp b/src/util/system.cpp
@@ -149,6 +149,19 @@ void ReleaseDirectoryLocks()
     dir_locks.clear();
 }
 
+bool DirIsWritable(const fs::path& directory)
+{
+    fs::path tmpFile = directory / fs::unique_path();
+
+    FILE* file = fsbridge::fopen(tmpFile, "a");
+    if (!file) return false;
+
+    fclose(file);
+    remove(tmpFile);
+
+    return true;
+}
+
 /**
  * Interpret a string argument as a boolean.
  *
diff --git a/src/util/system.h b/src/util/system.h
@@ -89,6 +89,7 @@ void AllocateFileRange(FILE* file, unsigned int offset, unsigned int length);
 bool CheckDiskSpace(const fs::path& dir, uint64_t additional_bytes = 0);
 bool RenameOver(fs::path src, fs::path dest);
 bool LockDirectory(const fs::path& directory, const std::string& lockfile_name, bool probe_only=false);
+bool DirIsWritable(const fs::path& directory);
 
 /** Release all directory locks. This is used for unit testing only, at runtime
  * the global destructor will take care of the locks.

Original file line number	Diff line number	Diff line change
`@@ -1190,6 +1190,9 @@ static bool LockDataDirectory(bool probeOnly)`
`1190`	`1190`	`{`
`1191`	`1191`	`// Make sure only a single PIVX process is using the data directory.`
`1192`	`1192`	`fs::path datadir = GetDataDir();`
	`1193`	`+ if (!DirIsWritable(datadir)) {`
	`1194`	`+ return UIError(strprintf(_("Cannot write to data directory '%s'; check permissions."), datadir.string()));`
	`1195`	`+ }`
`1193`	`1196`	`if (!LockDirectory(datadir, ".lock", probeOnly)) {`
`1194`	`1197`	`return UIError(strprintf(_("Cannot obtain a lock on data directory %s. %s is probably already running."), datadir.string(), _(PACKAGE_NAME)));`
`1195`	`1198`	`}`