diff --git a/src/basic/conf-files.h b/src/basic/conf-files.h
index 744ff80c09..81ebcd46b6 100644
--- a/src/basic/conf-files.h
+++ b/src/basic/conf-files.h
@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 #pragma once
 
+#include "macro.h"
+
 enum {
         CONF_FILES_EXECUTABLE    = 1 << 0,
         CONF_FILES_REGULAR       = 1 << 1,
@@ -9,7 +11,7 @@ enum {
         CONF_FILES_FILTER_MASKED = 1 << 4,
 };
 
-int conf_files_list(char ***ret, const char *suffix, const char *root, unsigned flags, const char *dir, ...);
+int conf_files_list(char ***ret, const char *suffix, const char *root, unsigned flags, const char *dir, ...) _sentinel_;
 int conf_files_list_strv(char ***ret, const char *suffix, const char *root, unsigned flags, const char* const* dirs);
 int conf_files_list_nulstr(char ***ret, const char *suffix, const char *root, unsigned flags, const char *dirs);
 int conf_files_insert(char ***strv, const char *root, char **dirs, const char *path);
diff --git a/src/basic/os-util.h b/src/basic/os-util.h
index 6b9e033941..27ec7ac8d7 100644
--- a/src/basic/os-util.h
+++ b/src/basic/os-util.h
@@ -8,5 +8,5 @@ int path_is_os_tree(const char *path);
 int open_os_release(const char *root, char **ret_path, int *ret_fd);
 int fopen_os_release(const char *root, char **ret_path, FILE **ret_file);
 
-int parse_os_release(const char *root, ...);
+int parse_os_release(const char *root, ...) _sentinel_;
 int load_os_release_pairs(const char *root, char ***ret);
diff --git a/src/basic/process-util.h b/src/basic/process-util.h
index 00b07517e6..ca4e4401a9 100644
--- a/src/basic/process-util.h
+++ b/src/basic/process-util.h
@@ -159,7 +159,7 @@ static inline int safe_fork(const char *name, ForkFlags flags, pid_t *ret_pid) {
         return safe_fork_full(name, NULL, 0, flags, ret_pid);
 }
 
-int fork_agent(const char *name, const int except[], size_t n_except, pid_t *pid, const char *path, ...);
+int fork_agent(const char *name, const int except[], size_t n_except, pid_t *pid, const char *path, ...) _sentinel_;
 
 int set_oom_score_adjust(int value);
 
diff --git a/src/core/execute.c b/src/core/execute.c
index b531dedf32..89964b7bc1 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -4659,8 +4659,7 @@ int exec_command_set(ExecCommand *c, const char *path, ...) {
                 return -ENOMEM;
         }
 
-        free(c->path);
-        c->path = p;
+        free_and_replace(c->path, p);
 
         return strv_free_and_replace(c->argv, l);
 }
diff --git a/src/core/execute.h b/src/core/execute.h
index a2ed477ebf..fa08746260 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -352,8 +352,8 @@ void exec_command_reset_status_array(ExecCommand *c, size_t n);
 void exec_command_reset_status_list_array(ExecCommand **c, size_t n);
 void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix);
 void exec_command_append_list(ExecCommand **l, ExecCommand *e);
-int exec_command_set(ExecCommand *c, const char *path, ...);
-int exec_command_append(ExecCommand *c, const char *path, ...);
+int exec_command_set(ExecCommand *c, const char *path, ...) _sentinel_;
+int exec_command_append(ExecCommand *c, const char *path, ...) _sentinel_;
 
 void exec_context_init(ExecContext *c);
 void exec_context_done(ExecContext *c);