diff --git a/core/git-access.cpp b/core/git-access.cpp
index 75d8bc610..2c957610d 100644
--- a/core/git-access.cpp
+++ b/core/git-access.cpp
@@ -136,16 +136,15 @@ extern "C" char *get_local_dir(const char *url, const char *branch)
 	// That's trivial with QString operations and painful to do right in plain C, so
 	// let's be lazy and call a C++ helper function
 	// just remember to free the string we get back
-	const char *remote = normalize_cloud_name(url);
+	std::string remote = normalize_cloud_name(url);
 
 	// That zero-byte update is so that we don't get hash
 	// collisions for "repo1 branch" vs "repo 1branch".
 	SHA1_Init(&ctx);
-	SHA1_Update(&ctx, remote, strlen(remote));
+	SHA1_Update(&ctx, remote.c_str(), remote.size());
 	SHA1_Update(&ctx, "", 1);
 	SHA1_Update(&ctx, branch, strlen(branch));
 	SHA1_Final(hash, &ctx);
-	free((void *)remote);
 	return format_string("%s/cloudstorage/%02x%02x%02x%02x%02x%02x%02x%02x",
 			system_default_directory(),
 			hash[0], hash[1], hash[2], hash[3],
@@ -432,9 +431,8 @@ static int try_to_git_merge(struct git_info *info, git_reference **local_p, git_
 			goto write_error;
 		if (get_authorship(info->repo, &author) < 0)
 			goto write_error;
-		const char *user_agent = subsurface_user_agent();
-		put_format(&msg, "Automatic merge\n\nCreated by %s\n", user_agent);
-		free((void *)user_agent);
+		std::string user_agent = subsurface_user_agent();
+		put_format(&msg, "Automatic merge\n\nCreated by %s\n", user_agent.c_str());
 		if (git_commit_create_v(&commit_oid, info->repo, NULL, author, author, NULL, mb_cstring(&msg), merged_tree, 2, local_commit, remote_commit))
 			goto write_error;
 		if (git_commit_lookup(&commit, info->repo, &commit_oid))
diff --git a/core/qthelper.cpp b/core/qthelper.cpp
index 44aa27509..f1077a762 100644
--- a/core/qthelper.cpp
+++ b/core/qthelper.cpp
@@ -434,11 +434,9 @@ QString getUserAgent()
 
 }
 
-extern "C" const char *subsurface_user_agent()
+std::string subsurface_user_agent()
 {
-	static QString uA = getUserAgent();
-
-	return copy_qstring(uA);
+	return getUserAgent().toStdString();
 }
 
 QString getUiLanguage()
@@ -1396,13 +1394,13 @@ extern "C" char *cloud_url()
 	return copy_qstring(filename);
 }
 
-extern "C" const char *normalize_cloud_name(const char *remote_in)
+std::string normalize_cloud_name(const char *remote_in)
 {
 	// replace ssrf-cloud-XX.subsurface... names with cloud.subsurface... names
 	// that trailing '/' is to match old code
 	QString ri(remote_in);
 	ri.replace(QRegularExpression(CLOUD_HOST_PATTERN), CLOUD_HOST_GENERIC "/");
-	return strdup(ri.toUtf8().constData());
+	return ri.toStdString();
 }
 
 extern "C" bool getProxyString(char **buffer)
@@ -1627,12 +1625,10 @@ void uiNotification(const QString &msg)
 // function to call to get changes for a git commit
 QString (*changesCallback)() = nullptr;
 
-extern "C" char *get_changes_made()
+std::string get_changes_made()
 {
-	if (changesCallback != nullptr)
-		return copy_qstring(changesCallback());
-	else
-		return nullptr;
+	return changesCallback != nullptr ? changesCallback().toStdString()
+					  : std::string();
 }
 
 // Generate a cylinder-renumber map for use when the n-th cylinder
diff --git a/core/qthelper.h b/core/qthelper.h
index 59fecf24c..12eb24f7d 100644
--- a/core/qthelper.h
+++ b/core/qthelper.h
@@ -98,6 +98,9 @@ std::vector<int> get_cylinder_map_for_add(int count, int n);
 
 extern QString (*changesCallback)();
 void uiNotification(const QString &msg);
+std::string get_changes_made();
+std::string subsurface_user_agent();
+std::string normalize_cloud_name(const char *remote_in);
 
 #if defined __APPLE__
 #define TITLE_OR_TEXT(_t, _m) "", _t + "\n" + _m
@@ -126,10 +129,8 @@ void copy_image_and_overwrite(const char *cfileName, const char *path, const cha
 char *move_away(const char *path);
 const char *local_file_path(struct picture *picture);
 char *cloud_url();
-const char *normalize_cloud_name(const char *remote_in);
 char *hashfile_name_string();
 char *picturedir_string();
-const char *subsurface_user_agent();
 enum deco_mode decoMode(bool in_planner);
 void parse_seabear_header(const char *filename, struct xml_params *params);
 char *get_current_date();
@@ -143,7 +144,6 @@ depth_t string_to_depth(const char *str);
 pressure_t string_to_pressure(const char *str);
 volume_t string_to_volume(const char *str, pressure_t workp);
 fraction_t string_to_fraction(const char *str);
-char *get_changes_made();
 void emit_reset_signal();
 
 extern void report_info(const char *fmt, ...);
diff --git a/core/save-git.cpp b/core/save-git.cpp
index a765a23cf..079a20306 100644
--- a/core/save-git.cpp
+++ b/core/save-git.cpp
@@ -1143,12 +1143,12 @@ static void create_commit_message(struct membuffer *msg, bool create_empty)
 {
 	int nr = divelog.dives->nr;
 	struct dive *dive = get_dive(nr-1);
-	char* changes_made = get_changes_made();
+	std::string changes_made = get_changes_made();
 
 	if (create_empty) {
 		put_string(msg, "Initial commit to create empty repo.\n\n");
-	} else if (!empty_string(changes_made)) {
-		put_format(msg, "Changes made: \n\n%s\n", changes_made);
+	} else if (!changes_made.empty()) {
+		put_format(msg, "Changes made: \n\n%s\n", changes_made.c_str());
 	} else if (dive) {
 		dive_trip_t *trip = dive->divetrip;
 		const char *location = get_dive_location(dive) ? : "no location";
@@ -1170,10 +1170,7 @@ static void create_commit_message(struct membuffer *msg, bool create_empty)
 		} while ((dc = dc->next) != NULL);
 		put_format(msg, "\n");
 	}
-	const char *user_agent = subsurface_user_agent();
-	put_format(msg, "Created by %s\n", user_agent);
-	free((void *)user_agent);
-	free(changes_made);
+	put_format(msg, "Created by %s\n", subsurface_user_agent().c_str());
 	if (verbose)
 		SSRF_INFO("Commit message:\n\n%s\n", mb_cstring(msg));
 }