macro: introduce TAKE_PTR() macro

This macro will read a pointer of any type, return it, and set the
pointer to NULL. This is useful as an explicit concept of passing
ownership of a memory area between pointers.

This takes inspiration from Rust:

https://doc.rust-lang.org/std/option/enum.Option.html#method.take

and was suggested by Alan Jenkins (@sourcejedi).

It drops ~160 lines of code from our codebase, which makes me like it.
Also, I think it clarifies passing of ownership, and thus helps
readability a bit (at least for the initiated who know the new macro)

coccinelle/take-ptr.cocci

@@ -0,0 +1,14 @@
+@@
+local idexpression p;
+expression q;
+@@
+- p = q;
+- q = NULL;
+- return p;
++ return TAKE_PTR(q);
+@@
+expression p, q;
+@@
+- p = q;
+- q = NULL;
++ p = TAKE_PTR(q);

src/basic/alloc-util.h

@@ -130,3 +130,12 @@ void* greedy_realloc0(void **p, size_t *allocated, size_t need, size_t size);
                 _new_ = alloca_align(_size_, (align));                  \
                 (void*)memset(_new_, 0, _size_);                        \
         })
+
+/* Takes inspiration from Rusts's Option::take() method: reads and returns a pointer, but at the same time resets it to
+ * NULL. See: https://doc.rust-lang.org/std/option/enum.Option.html#method.take */
+#define TAKE_PTR(ptr)                           \
+        ({                                      \
+                typeof(ptr) _ptr_ = (ptr);      \
+                (ptr) = NULL;                   \
+                _ptr_;                          \
+        })

src/basic/cap-list.c

@@ -103,8 +103,7 @@ int capability_set_to_string_alloc(uint64_t set, char **s) {
 
         str[n > 0 ? n - 1 : 0] = '\0'; /* truncate the last space, if it's there */
 
-        *s = str;
+        *s = TAKE_PTR(str);
-        str = NULL;
 
         return 0;
 }

src/basic/cgroup-util.c

@@ -1424,10 +1424,9 @@ int cg_pid_get_path_shifted(pid_t pid, const char *root, char **cgroup) {
         if (r < 0)
                 return r;
 
-        if (c == raw) {
+        if (c == raw)
-                *cgroup = raw;
+                *cgroup = TAKE_PTR(raw);
-                raw = NULL;
+        else {
-        } else {
                 char *n;
 
                 n = strdup(c);
@@ -2010,8 +2009,7 @@ int cg_slice_to_path(const char *unit, char **ret) {
         if (!strextend(&s, e, NULL))
                 return -ENOMEM;
 
-        *ret = s;
+        *ret = TAKE_PTR(s);
-        s = NULL;
 
         return 0;
 }
@@ -2301,8 +2299,7 @@ int cg_mask_to_string(CGroupMask mask, char **ret) {
         assert(s);
 
         s[n] = 0;
-        *ret = s;
+        *ret = TAKE_PTR(s);
-        s = NULL;
 
         return 0;
 }

src/basic/extract-word.c

@@ -194,8 +194,7 @@ finish:
 
 finish_force_next:
         s[sz] = 0;
-        *ret = s;
+        *ret = TAKE_PTR(s);
-        s = NULL;
 
         return 1;
 }

src/basic/fileio.c

@@ -330,8 +330,7 @@ int read_full_stream(FILE *f, char **contents, size_t *size) {
         }
 
         buf[l] = 0;
-        *contents = buf;
+        *contents = TAKE_PTR(buf);
-        buf = NULL; /* do not free */
 
         if (size)
                 *size = l;
@@ -1432,8 +1431,7 @@ int open_tmpfile_linkable(const char *target, int flags, char **ret_path) {
         if (fd < 0)
                 return -errno;
 
-        *ret_path = tmp;
+        *ret_path = TAKE_PTR(tmp);
-        tmp = NULL;
 
         return fd;
 }
@@ -1519,8 +1517,7 @@ int read_nul_string(FILE *f, char **ret) {
                         return -ENOMEM;
         }
 
-        *ret = x;
+        *ret = TAKE_PTR(x);
-        x = NULL;
 
         return 0;
 }

src/basic/fs-util.c

@@ -458,10 +458,8 @@ int get_files_in_directory(const char *path, char ***list) {
                         n++;
         }
 
-        if (list) {
+        if (list)
-                *list = l;
+                *list = TAKE_PTR(l);
-                l = NULL; /* avoid freeing */
-        }
 
         return n;
 }
@@ -838,10 +836,9 @@ int chase_symlinks(const char *path, const char *original_root, unsigned flags,
                 }
 
                 /* If this is not a symlink, then let's just add the name we read to what we already verified. */
-                if (!done) {
+                if (!done)
-                        done = first;
+                        done = TAKE_PTR(first);
-                        first = NULL;
+                else {
-                } else {
                         /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */
                         if (streq(done, "/"))
                                 *done = '\0';
@@ -863,10 +860,8 @@ int chase_symlinks(const char *path, const char *original_root, unsigned flags,
                         return -ENOMEM;
         }
 
-        if (ret) {
+        if (ret)
-                *ret = done;
+                *ret = TAKE_PTR(done);
-                done = NULL;
-        }
 
         if (flags & CHASE_OPEN) {
                 int q;

src/basic/locale-util.c

@@ -341,8 +341,7 @@ int get_keymaps(char ***ret) {
 
         strv_sort(l);
 
-        *ret = l;
+        *ret = TAKE_PTR(l);
-        l = NULL;
 
         return 0;
 }

src/basic/mount-util.c

@@ -81,10 +81,8 @@ int name_to_handle_at_loop(
 
                 if (name_to_handle_at(fd, path, h, &mnt_id, flags) >= 0) {
 
-                        if (ret_handle) {
+                        if (ret_handle)
-                                *ret_handle = h;
+                                *ret_handle = TAKE_PTR(h);
-                                h = NULL;
-                        }
 
                         if (ret_mnt_id)
                                 *ret_mnt_id = mnt_id;
@@ -951,8 +949,7 @@ int mount_option_mangle(
         }
 
         *ret_mount_flags = mount_flags;
-        *ret_remaining_options = ret;
+        *ret_remaining_options = TAKE_PTR(ret);
-        ret = NULL;
 
         return 0;
 }

src/basic/parse-util.c

@@ -324,8 +324,7 @@ int parse_syscall_and_errno(const char *in, char **name, int *error) {
                 return -EINVAL;
 
         *error = e;
-        *name = n;
+        *name = TAKE_PTR(n);
-        n = NULL;
 
         return 0;
 }

src/basic/path-util.c

@@ -290,8 +290,7 @@ char **path_strv_resolve(char **l, const char *root) {
                 r = chase_symlinks(t, root, 0, &u);
                 if (r == -ENOENT) {
                         if (root) {
-                                u = orig;
+                                u = TAKE_PTR(orig);
-                                orig = NULL;
                                 free(t);
                         } else
                                 u = t;

src/basic/proc-cmdline.c

@@ -204,10 +204,8 @@ int proc_cmdline_get_key(const char *key, unsigned flags, char **value) {
                 }
         }
 
-        if (value) {
+        if (value)
-                *value = ret;
+                *value = TAKE_PTR(ret);
-                ret = NULL;
-        }
 
         return found;
 }

src/basic/process-util.c

@@ -623,8 +623,7 @@ int get_process_environ(pid_t pid, char **env) {
         } else
                 outcome[sz] = '\0';
 
-        *env = outcome;
+        *env = TAKE_PTR(outcome);
-        outcome = NULL;
 
         return 0;
 }

src/basic/securebits-util.c

@@ -48,8 +48,7 @@ int secure_bits_to_string_alloc(int i, char **s) {
         if (len != 0)
                 str[len - 1] = '\0';
 
-        *s = str;
+        *s = TAKE_PTR(str);
-        str = NULL;
 
         return 0;
 }

src/basic/socket-util.c

@@ -985,8 +985,7 @@ int getpeersec(int fd, char **ret) {
         if (isempty(s))
                 return -EOPNOTSUPP;
 
-        *ret = s;
+        *ret = TAKE_PTR(s);
-        s = NULL;
 
         return 0;
 }

src/basic/strv.c

@@ -341,8 +341,7 @@ int strv_split_extract(char ***t, const char *s, const char *separators, Extract
                 if (!GREEDY_REALLOC(l, allocated, n + 2))
                         return -ENOMEM;
 
-                l[n++] = word;
+                l[n++] = TAKE_PTR(word);
-                word = NULL;
 
                 l[n] = NULL;
         }
@@ -353,8 +352,7 @@ int strv_split_extract(char ***t, const char *s, const char *separators, Extract
                         return -ENOMEM;
         }
 
-        *t = l;
+        *t = TAKE_PTR(l);
-        l = NULL;
 
         return (int) n;
 }

src/basic/terminal-util.c

@@ -707,10 +707,9 @@ int vtnr_from_tty(const char *tty) {
                 tty = active;
         }
 
-        if (tty == active) {
+        if (tty == active)
-                *ret = active;
+                *ret = TAKE_PTR(active);
-                active = NULL;
+        else {
-        } else {
                 char *tmp;
 
                 tmp = strdup(tty);
@@ -778,8 +777,7 @@ int get_kernel_consoles(char ***ret) {
                 goto fallback;
         }
 
-        *ret = l;
+        *ret = TAKE_PTR(l);
-        l = NULL;
 
         return 0;
 
@@ -788,8 +786,7 @@ fallback:
         if (r < 0)
                 return r;
 
-        *ret = l;
+        *ret = TAKE_PTR(l);
-        l = NULL;
 
         return 0;
 }

src/basic/unit-name.c

@@ -363,8 +363,7 @@ int unit_name_unescape(const char *f, char **ret) {
 
         *t = 0;
 
-        *ret = r;
+        *ret = TAKE_PTR(r);
-        r = NULL;
 
         return 0;
 }

src/busctl/busctl-introspect.c

@@ -275,10 +275,9 @@ static int parse_xml_node(Context *context, const char *prefix, unsigned n_depth
 
                                 free(node_path);
 
-                                if (name[0] == '/') {
+                                if (name[0] == '/')
-                                        node_path = name;
+                                        node_path = TAKE_PTR(name);
-                                        name = NULL;
+                                else {
-                                } else {
 
                                         if (endswith(prefix, "/"))
                                                 node_path = strappend(prefix, name);

src/core/cgroup.c

@@ -1381,8 +1381,7 @@ int unit_set_cgroup_path(Unit *u, const char *path) {
 
         unit_release_cgroup(u);
 
-        u->cgroup_path = p;
+        u->cgroup_path = TAKE_PTR(p);
-        p = NULL;
 
         return 1;
 }

src/core/dbus-execute.c

@@ -424,10 +424,8 @@ static int property_get_syscall_filter(
                                 if (r < 0)
                                         return -ENOMEM;
                         }
-                } else {
+                } else
-                        s = name;
+                        s = TAKE_PTR(name);
-                        name = NULL;
-                }
 
                 r = strv_consume(&l, s);
                 if (r < 0)
@@ -1125,8 +1123,7 @@ int bus_set_transient_exec_command(
                                 return -ENOMEM;
                         }
 
-                        c->argv = argv;
+                        c->argv = TAKE_PTR(argv);
-                        argv = NULL;
 
                         c->flags = b ? EXEC_COMMAND_IGNORE_FAILURE : 0;
 

src/core/dbus-job.c

@@ -274,8 +274,7 @@ int bus_job_coldplug_bus_track(Job *j) {
 
         assert(j);
 
-        deserialized_clients = j->deserialized_clients;
+        deserialized_clients = TAKE_PTR(j->deserialized_clients);
-        j->deserialized_clients = NULL;
 
         if (strv_isempty(deserialized_clients))
                 return 0;

src/core/dbus.c

@@ -501,8 +501,7 @@ static int bus_job_enumerate(sd_bus *bus, const char *path, void *userdata, char
 
         assert(hashmap_size(m->jobs) == k);
 
-        *nodes = l;
+        *nodes = TAKE_PTR(l);
-        l = NULL;
 
         return k;
 }
@@ -526,8 +525,7 @@ static int bus_unit_enumerate(sd_bus *bus, const char *path, void *userdata, cha
                 k++;
         }
 
-        *nodes = l;
+        *nodes = TAKE_PTR(l);
-        l = NULL;
 
         return k;
 }

src/core/dynamic-user.c

@@ -770,8 +770,7 @@ int dynamic_user_lookup_uid(Manager *m, uid_t uid, char **ret) {
         if (check_uid != uid) /* lock file doesn't match our own idea */
                 return -ESRCH;
 
-        *ret = user;
+        *ret = TAKE_PTR(user);
-        user = NULL;
 
         return 0;
 }

src/core/execute.c

@@ -1733,8 +1733,7 @@ static int build_environment(
         our_env[n_env++] = NULL;
         assert(n_env <= 12);
 
-        *ret = our_env;
+        *ret = TAKE_PTR(our_env);
-        our_env = NULL;
 
         return 0;
 }
@@ -1763,8 +1762,7 @@ static int build_pass_environment(const ExecContext *c, char ***ret) {
                 x = NULL;
         }
 
-        *ret = pass_env;
+        *ret = TAKE_PTR(pass_env);
-        pass_env = NULL;
 
         return 0;
 }
@@ -2290,9 +2288,7 @@ static int compile_bind_mounts(
 
         *ret_bind_mounts = bind_mounts;
         *ret_n_bind_mounts = n;
-        *ret_empty_directories = empty_directories;
+        *ret_empty_directories = TAKE_PTR(empty_directories);
-
-        empty_directories = NULL;
 
         return (int) n;
 
@@ -2696,8 +2692,7 @@ static int compile_suggested_paths(const ExecContext *c, const ExecParameters *p
                 }
         }
 
-        *ret = list;
+        *ret = TAKE_PTR(list);
-        list = NULL;
 
         return 0;
 }

src/core/load-fragment.c

@@ -1248,8 +1248,7 @@ int config_parse_exec_cpu_affinity(const char *unit,
         }
 
         if (!c->cpuset) {
-                c->cpuset = cpuset;
+                c->cpuset = TAKE_PTR(cpuset);
-                cpuset = NULL;
                 c->cpuset_ncpus = (unsigned) ncpus;
                 return 0;
         }
@@ -1257,8 +1256,7 @@ int config_parse_exec_cpu_affinity(const char *unit,
         if (c->cpuset_ncpus < (unsigned) ncpus) {
                 CPU_OR_S(CPU_ALLOC_SIZE(c->cpuset_ncpus), cpuset, c->cpuset, cpuset);
                 CPU_FREE(c->cpuset);
-                c->cpuset = cpuset;
+                c->cpuset = TAKE_PTR(cpuset);
-                cpuset = NULL;
                 c->cpuset_ncpus = (unsigned) ncpus;
                 return 0;
         }
@@ -2089,8 +2087,7 @@ int config_parse_user_group(
                         return -ENOEXEC;
                 }
 
-                n = k;
+                n = TAKE_PTR(k);
-                k = NULL;
         }
 
         free(*user);
@@ -2320,10 +2317,8 @@ int config_parse_environ(
                                            "Failed to resolve specifiers, ignoring: %s", word);
                                 continue;
                         }
-                } else {
+                } else
-                        k = word;
+                        k = TAKE_PTR(word);
-                        word = NULL;
-                }
 
                 if (!env_assignment_is_valid(k)) {
                         log_syntax(unit, LOG_ERR, filename, line, 0,
@@ -2390,10 +2385,8 @@ int config_parse_pass_environ(
                                            "Failed to resolve specifiers, ignoring: %s", word);
                                 continue;
                         }
-                } else {
+                } else
-                        k = word;
+                        k = TAKE_PTR(word);
-                        word = NULL;
-                }
 
                 if (!env_name_is_valid(k)) {
                         log_syntax(unit, LOG_ERR, filename, line, 0,
@@ -2469,10 +2462,8 @@ int config_parse_unset_environ(
                                            "Failed to resolve specifiers, ignoring: %s", word);
                                 continue;
                         }
-                } else {
+                } else
-                        k = word;
+                        k = TAKE_PTR(word);
-                        word = NULL;
-                }
 
                 if (!env_assignment_is_valid(k) && !env_name_is_valid(k)) {
                         log_syntax(unit, LOG_ERR, filename, line, 0,
@@ -3515,8 +3506,7 @@ int config_parse_device_allow(
         if (!a)
                 return log_oom();
 
-        a->path = path;
+        a->path = TAKE_PTR(path);
-        path = NULL;
         a->r = !!strchr(m, 'r');
         a->w = !!strchr(m, 'w');
         a->m = !!strchr(m, 'm');
@@ -3615,8 +3605,7 @@ int config_parse_io_device_weight(
         if (!w)
                 return log_oom();
 
-        w->path = path;
+        w->path = TAKE_PTR(path);
-        path = NULL;
 
         w->weight = u;
 
@@ -3701,8 +3690,7 @@ int config_parse_io_limit(
                 if (!l)
                         return log_oom();
 
-                l->path = path;
+                l->path = TAKE_PTR(path);
-                path = NULL;
                 for (ttype = 0; ttype < _CGROUP_IO_LIMIT_TYPE_MAX; ttype++)
                         l->limits[ttype] = cgroup_io_limit_defaults[ttype];
 
@@ -3804,8 +3792,7 @@ int config_parse_blockio_device_weight(
         if (!w)
                 return log_oom();
 
-        w->path = path;
+        w->path = TAKE_PTR(path);
-        path = NULL;
 
         w->weight = u;
 
@@ -3885,8 +3872,7 @@ int config_parse_blockio_bandwidth(
                 if (!b)
                         return log_oom();
 
-                b->path = path;
+                b->path = TAKE_PTR(path);
-                path = NULL;
                 b->rbps = CGROUP_LIMIT_MAX;
                 b->wbps = CGROUP_LIMIT_MAX;
 

src/core/mount-setup.c

@@ -315,10 +315,8 @@ int mount_cgroup_controllers(char ***join_controllers) {
                         options = strv_join(*k, ",");
                         if (!options)
                                 return log_oom();
-                } else {
+                } else
-                        options = controller;
+                        options = TAKE_PTR(controller);
-                        controller = NULL;
-                }
 
                 where = strappend("/sys/fs/cgroup/", options);
                 if (!where)

src/core/service.c

@@ -2554,8 +2554,7 @@ static int service_deserialize_exec_command(Unit *u, const char *key, const char
                         state = STATE_EXEC_COMMAND_PATH;
                         break;
                 case STATE_EXEC_COMMAND_PATH:
-                        path = arg;
+                        path = TAKE_PTR(arg);
-                        arg = NULL;
                         state = STATE_EXEC_COMMAND_ARGS;
 
                         if (!path_is_absolute(path))

src/core/unit.c

@@ -709,10 +709,8 @@ static int set_complete_move(Set **s, Set **other) {
 
         if (*s)
                 return set_move(*s, *other);
-        else {
+        else
-                *s = *other;
+                *s = TAKE_PTR(*other);
-                *other = NULL;
-        }
 
         return 0;
 }
@@ -726,10 +724,8 @@ static int hashmap_complete_move(Hashmap **s, Hashmap **other) {
 
         if (*s)
                 return hashmap_move(*s, *other);
-        else {
+        else
-                *s = *other;
+                *s = TAKE_PTR(*other);
-                *other = NULL;
-        }
 
         return 0;
 }
@@ -4017,8 +4013,7 @@ static int user_from_unit_name(Unit *u, char **ret) {
                 return r;
 
         if (valid_user_group_name(n)) {
-                *ret = n;
+                *ret = TAKE_PTR(n);
-                n = NULL;
                 return 0;
         }
 
@@ -4220,7 +4215,7 @@ char* unit_escape_setting(const char *s, UnitWriteFlags flags, char **buf) {
 char* unit_concat_strv(char **l, UnitWriteFlags flags) {
         _cleanup_free_ char *result = NULL;
         size_t n = 0, allocated = 0;
-        char **i, *ret;
+        char **i;
 
         /* Takes a list of strings, escapes them, and concatenates them. This may be used to format command lines in a
          * way suitable for ExecStart= stanzas */
@@ -4255,10 +4250,7 @@ char* unit_concat_strv(char **l, UnitWriteFlags flags) {
 
         result[n] = 0;
 
-        ret = result;
+        return TAKE_PTR(result);
-        result = NULL;
-
-        return ret;
 }
 
 int unit_write_setting(Unit *u, UnitWriteFlags flags, const char *name, const char *data) {

src/coredump/coredump.c

@@ -584,8 +584,7 @@ static int compose_open_fds(pid_t pid, char **open_fds) {
         if (errno > 0)
                 return -errno;
 
-        *open_fds = buffer;
+        *open_fds = TAKE_PTR(buffer);
-        buffer = NULL;
 
         return 0;
 }

src/coredump/coredumpctl.c

@@ -764,8 +764,7 @@ static int save_core(sd_journal *j, FILE *file, char **path, bool *unlink_temp)
                         return log_error_errno(errno, "File \"%s\" is not readable: %m", filename);
 
                 if (path && !endswith(filename, ".xz") && !endswith(filename, ".lz4")) {
-                        *path = filename;
+                        *path = TAKE_PTR(filename);
-                        filename = NULL;
 
                         return 0;
                 }

src/coredump/stacktrace.c

@@ -184,8 +184,7 @@ int coredump_make_stack_trace(int fd, const char *executable, char **ret) {
 
         c.f = safe_fclose(c.f);
 
-        *ret = buf;
+        *ret = TAKE_PTR(buf);
-        buf = NULL;
 
         r = 0;
 

src/cryptsetup/cryptsetup.c

@@ -402,8 +402,7 @@ static int get_password(const char *vol, const char *src, usec_t until, bool acc
                 *p = c;
         }
 
-        *ret = passwords;
+        *ret = TAKE_PTR(passwords);
-        passwords = NULL;
 
         return 0;
 }

src/environment-d-generator/environment-d-generator.c

@@ -45,8 +45,7 @@ static int environment_dirs(char ***ret) {
         if (r < 0)
                 return r;
 
-        *ret = dirs;
+        *ret = TAKE_PTR(dirs);
-        dirs = NULL;
         return 0;
 }
 

src/firstboot/firstboot.c

@@ -575,8 +575,7 @@ static int prompt_root_password(void) {
                         continue;
                 }
 
-                arg_root_password = a;
+                arg_root_password = TAKE_PTR(a);
-                a = NULL;
                 break;
         }
 

src/import/importd.c

@@ -1083,8 +1083,7 @@ static int transfer_node_enumerator(sd_bus *bus, const char *path, void *userdat
                 k++;
         }
 
-        *nodes = l;
+        *nodes = TAKE_PTR(l);
-        l = NULL;
 
         return 1;
 }

src/import/pull-common.c

@@ -124,8 +124,7 @@ int pull_find_old_etags(
                         return r;
         }
 
-        *etags = l;
+        *etags = TAKE_PTR(l);
-        l = NULL;
 
         return 0;
 }

src/journal/mmap-cache.c

@@ -220,8 +220,7 @@ static void context_detach_window(Context *c) {
         if (!c->window)
                 return;
 
-        w = c->window;
+        w = TAKE_PTR(c->window);
-        c->window = NULL;
         LIST_REMOVE(by_window, w->contexts, c);
 
         if (!w->contexts && !w->keep_always) {

src/libsystemd-network/dhcp-option.c

@@ -253,10 +253,8 @@ int dhcp_option_parse(DHCPMessage *message, size_t len, dhcp_option_callback_t c
         if (message_type == 0)
                 return -ENOMSG;
 
-        if (_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE)) {
+        if (_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE))
-                *_error_message = error_message;
+                *_error_message = TAKE_PTR(error_message);
-                error_message = NULL;
-        }
 
         return message_type;
 }

src/libsystemd-network/dhcp6-option.c

@@ -617,8 +617,7 @@ int dhcp6_option_parse_domainname(const uint8_t *optval, uint16_t optlen, char *
                 idx++;
         }
 
-        *str_arr = names;
+        *str_arr = TAKE_PTR(names);
-        names = NULL;
 
         return idx;
 

src/libsystemd-network/network-internal.c

@@ -276,10 +276,9 @@ int config_parse_ifalias(const char *unit,
         }
 
         free(*s);
-        if (*n) {
+        if (*n)
-                *s = n;
+                *s = TAKE_PTR(n);
-                n = NULL;
+        else
-        } else
                 *s = NULL;
 
         return 0;
@@ -437,8 +436,7 @@ int deserialize_in_addrs(struct in_addr **ret, const char *string) {
                 size++;
         }
 
-        *ret = addresses;
+        *ret = TAKE_PTR(addresses);
-        addresses = NULL;
 
         return size;
 }
@@ -491,8 +489,7 @@ int deserialize_in6_addrs(struct in6_addr **ret, const char *string) {
                 size++;
         }
 
-        *ret = addresses;
+        *ret = TAKE_PTR(addresses);
-        addresses = NULL;
 
         return size;
 }
@@ -585,8 +582,7 @@ int deserialize_dhcp_routes(struct sd_dhcp_route **ret, size_t *ret_size, size_t
 
         *ret_size = size;
         *ret_allocated = allocated;
-        *ret = routes;
+        *ret = TAKE_PTR(routes);
-        routes = NULL;
 
         return 0;
 }

src/libsystemd-network/sd-dhcp-lease.c

@@ -807,8 +807,7 @@ int dhcp_lease_parse_search_domains(const uint8_t *option, size_t len, char ***d
                       pos = next_chunk;
         }
 
-        *domains = names;
+        *domains = TAKE_PTR(names);
-        names = NULL;
 
         return cnt;
 }

src/libsystemd/sd-bus/bus-objects.c

@@ -1470,8 +1470,7 @@ static struct node *bus_node_allocate(sd_bus *bus, const char *path) {
                 return NULL;
 
         n->parent = parent;
-        n->path = s;
+        n->path = TAKE_PTR(s);
-        s = NULL; /* do not free */
 
         r = hashmap_put(bus->nodes, n->path, n);
         if (r < 0) {

src/libsystemd/sd-bus/sd-bus.c

@@ -1342,8 +1342,7 @@ int bus_set_address_user(sd_bus *b) {
         if (asprintf(&s, DEFAULT_USER_BUS_ADDRESS_FMT, ee) < 0)
                 return -ENOMEM;
 
-        b->address = s;
+        b->address = TAKE_PTR(s);
-        s = NULL;
 
         return 0;
 }

src/libsystemd/sd-daemon/sd-daemon.c

@@ -141,8 +141,7 @@ _public_ int sd_listen_fds_with_names(int unset_environment, char ***names) {
                         return r;
         }
 
-        *names = l;
+        *names = TAKE_PTR(l);
-        l = NULL;
 
         return n_fds;
 }

src/libsystemd/sd-device/sd-device.c

@@ -1297,8 +1297,7 @@ int device_get_id_filename(sd_device *device, const char **ret) {
                         }
                 }
 
-                device->id_filename = id;
+                device->id_filename = TAKE_PTR(id);
-                id = NULL;
         }
 
         *ret = device->id_filename;

src/libsystemd/sd-login/sd-login.c

@@ -325,8 +325,7 @@ _public_ int sd_uid_get_display(uid_t uid, char **session) {
         if (isempty(s))
                 return -ENODATA;
 
-        *session = s;
+        *session = TAKE_PTR(s);
-        s = NULL;
 
         return 0;
 }
@@ -355,8 +354,7 @@ static int file_of_seat(const char *seat, char **_p) {
         if (!p)
                 return -ENOMEM;
 
-        *_p = p;
+        *_p = TAKE_PTR(p);
-        p = NULL;
         return 0;
 }
 
@@ -529,8 +527,7 @@ _public_ int sd_session_get_state(const char *session, char **state) {
         if (isempty(s))
                 return -EIO;
 
-        *state = s;
+        *state = TAKE_PTR(s);
-        s = NULL;
 
         return 0;
 }
@@ -575,8 +572,7 @@ static int session_get_string(const char *session, const char *field, char **val
         if (isempty(s))
                 return -ENODATA;
 
-        *value = s;
+        *value = TAKE_PTR(s);
-        s = NULL;
         return 0;
 }
 
@@ -681,10 +677,8 @@ _public_ int sd_seat_get_active(const char *seat, char **session, uid_t *uid) {
                         return r;
         }
 
-        if (session && s) {
+        if (session && s)
-                *session = s;
+                *session = TAKE_PTR(s);
-                s = NULL;
-        }
 
         return 0;
 }
@@ -909,10 +903,9 @@ _public_ int sd_get_machine_names(char ***machines) {
                 *b = NULL;
         }
 
-        if (machines) {
+        if (machines)
-                *machines = l;
+                *machines = TAKE_PTR(l);
-                l = NULL;
+
-        }
         return r;
 }
 
@@ -933,8 +926,7 @@ _public_ int sd_machine_get_class(const char *machine, char **class) {
         if (!c)
                 return -EIO;
 
-        *class = c;
+        *class = TAKE_PTR(c);
-        c = NULL;
 
         return 0;
 }

src/libsystemd/sd-netlink/netlink-message.c

@@ -803,8 +803,7 @@ static int netlink_container_parse(sd_netlink_message *m,
                 attributes[type].net_byteorder = RTA_FLAGS(rta) & NLA_F_NET_BYTEORDER;
         }
 
-        container->attributes = attributes;
+        container->attributes = TAKE_PTR(attributes);
-        attributes = NULL;
         container->n_attributes = count;
 
         return 0;

src/libsystemd/sd-network/sd-network.c

@@ -51,8 +51,7 @@ _public_ int sd_network_get_operational_state(char **state) {
         if (isempty(s))
                 return -ENODATA;
 
-        *state = s;
+        *state = TAKE_PTR(s);
-        s = NULL;
 
         return 0;
 }
@@ -81,8 +80,7 @@ static int network_get_strv(const char *key, char ***ret) {
         strv_uniq(a);
         r = strv_length(a);
 
-        *ret = a;
+        *ret = TAKE_PTR(a);
-        a = NULL;
 
         return r;
 }
@@ -121,8 +119,7 @@ static int network_link_get_string(int ifindex, const char *field, char **ret) {
         if (isempty(s))
                 return -ENODATA;
 
-        *ret = s;
+        *ret = TAKE_PTR(s);
-        s = NULL;
 
         return 0;
 }
@@ -154,8 +151,7 @@ static int network_link_get_strv(int ifindex, const char *key, char ***ret) {
         strv_uniq(a);
         r = strv_length(a);
 
-        *ret = a;
+        *ret = TAKE_PTR(a);
-        a = NULL;
 
         return r;
 }
@@ -263,8 +259,7 @@ static int network_link_get_ifindexes(int ifindex, const char *key, int **ret) {
         if (ifis)
                 ifis[c] = 0; /* Let's add a 0 ifindex to the end, to be nice */
 
-        *ret = ifis;
+        *ret = TAKE_PTR(ifis);
-        ifis = NULL;
 
         return c;
 }

src/libudev/libudev-enumerate.c

@@ -69,7 +69,6 @@ struct udev_enumerate {
  **/
 _public_ struct udev_enumerate *udev_enumerate_new(struct udev *udev) {
         _cleanup_free_ struct udev_enumerate *udev_enumerate = NULL;
-        struct udev_enumerate *ret;
         int r;
 
         assert_return_errno(udev, NULL, EINVAL);
@@ -97,10 +96,7 @@ _public_ struct udev_enumerate *udev_enumerate_new(struct udev *udev) {
 
         udev_list_init(udev, &udev_enumerate->devices_list, false);
 
-        ret = udev_enumerate;
+        return TAKE_PTR(udev_enumerate);
-        udev_enumerate = NULL;
-
-        return ret;
 }
 
 /**

src/locale/keymap-util.c

@@ -278,8 +278,7 @@ int locale_write_data(Context *c, char ***settings) {
         if (r < 0)
                 return r;
 
-        *settings = l;
+        *settings = TAKE_PTR(l);
-        l = NULL;
         return 0;
 }
 
@@ -539,8 +538,7 @@ int find_converted_keymap(const char *x11_layout, const char *x11_variant, char
                         log_debug("Found converted keymap %s at %s",
                                   n, uncompressed ? p : pz);
 
-                        *new_keymap = n;
+                        *new_keymap = TAKE_PTR(n);
-                        n = NULL;
                         return 1;
                 }
         }

src/login/logind-seat.c

@@ -560,8 +560,7 @@ void seat_complete_switch(Seat *s) {
         if (!s->pending_switch)
                 return;
 
-        session = s->pending_switch;
+        session = TAKE_PTR(s->pending_switch);
-        s->pending_switch = NULL;
 
         seat_set_active(s, session);
 }

src/login/logind-session.c

@@ -1271,8 +1271,7 @@ int session_set_controller(Session *s, const char *sender, bool force, bool prep
         }
 
         session_release_controller(s, true);
-        s->controller = name;
+        s->controller = TAKE_PTR(name);
-        name = NULL;
         session_save(s);
 
         return 0;

src/login/logind.c

@@ -438,8 +438,7 @@ static int parse_fdname(const char *fdname, char **session_id, dev_t *dev) {
                 return r;
 
         *dev = makedev(major, minor);
-        *session_id = id;
+        *session_id = TAKE_PTR(id);
-        id = NULL;
 
         return 0;
 }

src/machine/machine-dbus.c

@@ -1475,8 +1475,7 @@ int machine_node_enumerator(sd_bus *bus, const char *path, void *userdata, char
                         return r;
         }
 
-        *nodes = l;
+        *nodes = TAKE_PTR(l);
-        l = NULL;
 
         return 1;
 }

src/mount/mount-tool.c

@@ -766,16 +766,14 @@ static int find_mount_points(const char *what, char ***list) {
                 if (!GREEDY_REALLOC(l, bufsize, n + 2))
                         return log_oom();
 
-                l[n++] = where;
+                l[n++] = TAKE_PTR(where);
-                where = NULL;
         }
 
         if (!GREEDY_REALLOC(l, bufsize, n + 1))
                 return log_oom();
 
         l[n] = NULL;
-        *list = l;
+        *list = TAKE_PTR(l);
-        l = NULL; /* avoid freeing */
 
         return n;
 }
@@ -827,8 +825,7 @@ static int find_loop_device(const char *backing_file, char **loop_dev) {
         if (!l)
                 return -ENXIO;
 
-        *loop_dev = l;
+        *loop_dev = TAKE_PTR(l);
-        l = NULL; /* avoid freeing */
 
         return 0;
 }

src/network/netdev/netdev.c

@@ -488,8 +488,7 @@ int netdev_get_mac(const char *ifname, struct ether_addr **ret) {
         mac->ether_addr_octet[0] &= 0xfe;        /* clear multicast bit */
         mac->ether_addr_octet[0] |= 0x02;        /* set local assignment bit (IEEE802) */
 
-        *ret = mac;
+        *ret = TAKE_PTR(mac);
-        mac = NULL;
 
         return 0;
 }

src/network/netdev/wireguard.c

@@ -228,8 +228,7 @@ static int on_resolve_retry(sd_event_source *s, usec_t usec, void *userdata) {
 
         w->resolve_retry_event_source = sd_event_source_unref(w->resolve_retry_event_source);
 
-        w->unresolved_endpoints = w->failed_endpoints;
+        w->unresolved_endpoints = TAKE_PTR(w->failed_endpoints);
-        w->failed_endpoints = NULL;
 
         resolve_endpoints(netdev);
 

src/network/networkd-link-bus.c

@@ -82,8 +82,7 @@ int link_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***
         }
 
         l[c] = NULL;
-        *nodes = l;
+        *nodes = TAKE_PTR(l);
-        l = NULL;
 
         return 1;
 }

src/network/networkd-network-bus.c

@@ -122,8 +122,7 @@ int network_node_enumerator(sd_bus *bus, const char *path, void *userdata, char
                         return r;
         }
 
-        *nodes = l;
+        *nodes = TAKE_PTR(l);
-        l = NULL;
 
         return 1;
 }

src/network/networkd-network.c

@@ -72,8 +72,7 @@ int network_config_section_new(const char *filename, unsigned line, NetworkConfi
         strcpy(cs->filename, filename);
         cs->line = line;
 
-        *s = cs;
+        *s = TAKE_PTR(cs);
-        cs = NULL;
 
         return 0;
 }

src/network/networkd-radv.c

@@ -126,8 +126,7 @@ int prefix_new(Prefix **ret) {
         if (sd_radv_prefix_new(&prefix->radv_prefix) < 0)
                 return -ENOMEM;
 
-        *ret = prefix;
+        *ret = TAKE_PTR(prefix);
-        prefix = NULL;
 
         return 0;
 }
@@ -344,8 +343,7 @@ static int radv_get_ip6dns(Network *network, struct in6_addr **dns,
         }
 
         if (addresses) {
-                *dns = addresses;
+                *dns = TAKE_PTR(addresses);
-                addresses = NULL;
 
                 *n_dns = n_addresses;
         }

src/network/networkd-routing-policy-rule.c

@@ -857,8 +857,7 @@ static int routing_policy_rule_read_full_file(const char *state_file, char **ret
         if (size <= 0)
                 return -ENODATA;
 
-        *ret = s;
+        *ret = TAKE_PTR(s);
-        s = NULL;
 
         return size;
 }

src/nspawn/nspawn-mount.c

@@ -308,8 +308,7 @@ int overlay_mount_parse(CustomMount **l, unsigned *n, const char *s, bool read_o
                     !source_path_is_valid(lower[1]))
                         return -EINVAL;
 
-                upper = lower[1];
+                upper = TAKE_PTR(lower[1]);
-                lower[1] = NULL;
 
                 destination = strdup(upper[0] == '+' ? upper+1 : upper); /* take the destination without "+" prefix */
                 if (!destination)
@@ -321,8 +320,7 @@ int overlay_mount_parse(CustomMount **l, unsigned *n, const char *s, bool read_o
                  * the "upper", and all before that the "lower" directories. */
 
                 destination = lower[k - 1];
-                upper = lower[k - 2];
+                upper = TAKE_PTR(lower[k - 2]);
-                lower[k - 2] = NULL;
 
                 STRV_FOREACH(i, lower)
                         if (!source_path_is_valid(*i))

src/nspawn/nspawn.c

@@ -1175,8 +1175,7 @@ static int parse_argv(int argc, char *argv[]) {
                  * accept this here, and silently make "--ephemeral --template=" equivalent to "--ephemeral
                  * --directory=". */
 
-                arg_directory = arg_template;
+                arg_directory = TAKE_PTR(arg_template);
-                arg_template = NULL;
         }
 
         if (arg_template && !(arg_directory || arg_machine)) {

src/resolve/resolved-dns-search-domain.c

@@ -56,8 +56,7 @@ int dns_search_domain_new(
         d->n_ref = 1;
         d->manager = m;
         d->type = type;
-        d->name = normalized;
+        d->name = TAKE_PTR(normalized);
-        normalized = NULL;
 
         switch (type) {
 

src/resolve/resolved-dns-zone.c

@@ -36,8 +36,7 @@ void dns_zone_item_probe_stop(DnsZoneItem *i) {
         if (!i->probe_transaction)
                 return;
 
-        t = i->probe_transaction;
+        t = TAKE_PTR(i->probe_transaction);
-        i->probe_transaction = NULL;
 
         set_remove(t->notify_zone_items, i);
         set_remove(t->notify_zone_items_done, i);

src/resolve/resolved-dnssd-bus.c

@@ -139,8 +139,7 @@ int dnssd_node_enumerator(sd_bus *bus, const char *path, void *userdata, char **
         }
 
         l[c] = NULL;
-        *nodes = l;
+        *nodes = TAKE_PTR(l);
-        l = NULL;
 
         return 1;
 }

src/resolve/resolved-dnssd.c

@@ -198,8 +198,7 @@ int dnssd_render_instance_name(DnssdService *s, char **ret_name) {
                 return -EINVAL;
         }
 
-        *ret_name = name;
+        *ret_name = TAKE_PTR(name);
-        name = NULL;
 
         return 0;
 }
@@ -319,8 +318,7 @@ int dnssd_txt_item_new_from_string(const char *key, const char *value, DnsTxtIte
         }
         i->length = length;
 
-        *ret_item = i;
+        *ret_item = TAKE_PTR(i);
-        i = NULL;
 
         return 0;
 }
@@ -345,8 +343,7 @@ int dnssd_txt_item_new_from_data(const char *key, const void *data, const size_t
         }
         i->length = length;
 
-        *ret_item = i;
+        *ret_item = TAKE_PTR(i);
-        i = NULL;
 
         return 0;
 }

src/resolve/resolved-link-bus.c

@@ -496,8 +496,7 @@ int bus_link_method_set_dnssec_negative_trust_anchors(sd_bus_message *message, v
         }
 
         set_free_free(l->dnssec_negative_trust_anchors);
-        l->dnssec_negative_trust_anchors = ns;
+        l->dnssec_negative_trust_anchors = TAKE_PTR(ns);
-        ns = NULL;
 
         (void) link_save_user(l);
 
@@ -621,8 +620,7 @@ int link_node_enumerator(sd_bus *bus, const char *path, void *userdata, char ***
         }
 
         l[c] = NULL;
-        *nodes = l;
+        *nodes = TAKE_PTR(l);
-        l = NULL;
 
         return 1;
 }

src/resolve/resolved-link.c

@@ -440,8 +440,7 @@ static int link_update_dnssec_negative_trust_anchors(Link *l) {
                 return r;
 
         set_free_free(l->dnssec_negative_trust_anchors);
-        l->dnssec_negative_trust_anchors = ns;
+        l->dnssec_negative_trust_anchors = TAKE_PTR(ns);
-        ns = NULL;
 
         return 0;
 
@@ -1293,8 +1292,7 @@ int link_load_user(Link *l) {
                 if (r < 0)
                         goto fail;
 
-                l->dnssec_negative_trust_anchors = ns;
+                l->dnssec_negative_trust_anchors = TAKE_PTR(ns);
-                ns = NULL;
         }
 
         return 0;

src/resolve/resolved-manager.c

@@ -396,11 +396,8 @@ static int determine_hostname(char **full_hostname, char **llmnr_hostname, char
         if (r < 0)
                 return log_error_errno(r, "Failed to determine mDNS hostname: %m");
 
-        *llmnr_hostname = n;
+        *llmnr_hostname = TAKE_PTR(n);
-        n = NULL;
+        *full_hostname = TAKE_PTR(h);
-
-        *full_hostname = h;
-        h = NULL;
 
         return 0;
 }
@@ -445,11 +442,8 @@ static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname,
         if (!h)
                 return log_oom();
 
-        *llmnr_hostname = n;
+        *llmnr_hostname = TAKE_PTR(n);
-        n = NULL;
+        *mdns_hostname = TAKE_PTR(m);
-
-        *mdns_hostname = m;
-        m = NULL;
 
         *full_hostname = h;
 

src/shared/ask-password-api.c

@@ -730,8 +730,7 @@ int ask_password_agent(
         if (keyname)
                 (void) add_to_keyring_and_log(keyname, flags, l);
 
-        *ret = l;
+        *ret = TAKE_PTR(l);
-        l = NULL;
         r = 0;
 
 finish:

src/shared/bus-util.c

@@ -1094,8 +1094,7 @@ static int map_basic(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_
                         return r;
 
                 strv_free(*p);
-                *p = l;
+                *p = TAKE_PTR(l);
-                l = NULL;
                 return 0;
         }
 

src/shared/cgroup-show.c

@@ -189,8 +189,7 @@ int show_cgroup_by_path(
                         free(last);
                 }
 
-                last = k;
+                last = TAKE_PTR(k);
-                k = NULL;
         }
 
         if (r < 0)

src/shared/dns-domain.c

@@ -295,8 +295,7 @@ int dns_label_escape_new(const char *p, size_t l, char **ret) {
         if (r < 0)
                 return r;
 
-        *ret = s;
+        *ret = TAKE_PTR(s);
-        s = NULL;
 
         return r;
 }
@@ -601,8 +600,7 @@ int dns_name_endswith(const char *name, const char *suffix) {
 
                         /* Not the same, let's jump back, and try with the next label again */
                         s = suffix;
-                        n = saved_n;
+                        n = TAKE_PTR(saved_n);
-                        saved_n = NULL;
                 }
         }
 }

src/shared/efivars.c

@@ -249,8 +249,7 @@ int efi_get_variable(
         ((char*) buf)[st.st_size - 4] = 0;
         ((char*) buf)[st.st_size - 4 + 1] = 0;
 
-        *value = buf;
+        *value = TAKE_PTR(buf);
-        buf = NULL;
         *size = (size_t) st.st_size - 4;
 
         if (attribute)
@@ -563,8 +562,7 @@ int efi_get_boot_order(uint16_t **order) {
             l / sizeof(uint16_t) > INT_MAX)
                 return -EINVAL;
 
-        *order = buf;
+        *order = TAKE_PTR(buf);
-        buf = NULL;
         return (int) (l / sizeof(uint16_t));
 }
 

src/shared/fdset.c

@@ -25,6 +25,7 @@
 
 #include "sd-daemon.h"
 
+#include "alloc-util.h"
 #include "dirent-util.h"
 #include "fd-util.h"
 #include "fdset.h"
@@ -168,8 +169,7 @@ int fdset_new_fill(FDSet **_s) {
         }
 
         r = 0;
-        *_s = s;
+        *_s = TAKE_PTR(s);
-        s = NULL;
 
 finish:
         /* We won't close the fds here! */

src/shared/fstab-util.c

@@ -169,10 +169,8 @@ answer:
 
                 *filtered = f;
         }
-        if (value) {
+        if (value)
-                *value = v;
+                *value = TAKE_PTR(v);
-                v = NULL;
-        }
 
         return !!n;
 }
@@ -201,8 +199,7 @@ int fstab_extract_values(const char *opts, const char *name, char ***values) {
                         return r;
         }
 
-        *values = res;
+        *values = TAKE_PTR(res);
-        res = NULL;
 
         return !!*values;
 }

src/shared/import-util.c

@@ -153,8 +153,7 @@ int raw_strip_suffixes(const char *p, char **ret) {
                         break;
         }
 
-        *ret = q;
+        *ret = TAKE_PTR(q);
-        q = NULL;
 
         return 0;
 }

src/shared/install-printf.c

@@ -50,10 +50,8 @@ static int specifier_prefix_and_instance(char specifier, void *data, void *userd
                 if (!ans)
                         return -ENOMEM;
                 *ret = ans;
-        } else {
+        } else
-                *ret = prefix;
+                *ret = TAKE_PTR(prefix);
-                prefix = NULL;
-        }
 
         return 0;
 }

src/shared/install.c

@@ -1422,8 +1422,7 @@ static int unit_file_search(
                 r = unit_file_load_or_readlink(c, info, path, paths->root_dir, flags);
 
                 if (r >= 0) {
-                        info->path = path;
+                        info->path = TAKE_PTR(path);
-                        path = NULL;
                         result = r;
                         found_unit = true;
                         break;
@@ -1446,8 +1445,7 @@ static int unit_file_search(
 
                         r = unit_file_load_or_readlink(c, info, path, paths->root_dir, flags);
                         if (r >= 0) {
-                                info->path = path;
+                                info->path = TAKE_PTR(path);
-                                path = NULL;
                                 result = r;
                                 found_unit = true;
                                 break;
@@ -1754,8 +1752,7 @@ static int install_info_symlink_wants(
                 if (r < 0)
                         return r;
 
-                path = instance.path;
+                path = TAKE_PTR(instance.path);
-                instance.path = NULL;
 
                 if (instance.type == UNIT_FILE_TYPE_MASKED) {
                         unit_file_changes_add(changes, n_changes, -ERFKILL, path, NULL);

src/shared/machine-image.c

@@ -80,7 +80,6 @@ Image *image_unref(Image *i) {
 
 static char **image_settings_path(Image *image) {
         _cleanup_strv_free_ char **l = NULL;
-        char **ret;
         const char *fn, *s;
         unsigned i = 0;
 
@@ -104,10 +103,7 @@ static char **image_settings_path(Image *image) {
         if (!l[i])
                 return NULL;
 
-        ret = l;
+        return TAKE_PTR(l);
-        l = NULL;
-
-        return ret;
 }
 
 static char *image_roothash_path(Image *image) {

src/shared/nsflags.c

@@ -114,8 +114,7 @@ int namespace_flag_to_string_many(unsigned long flags, char **ret) {
                         return -ENOMEM;
         }
 
-        *ret = s;
+        *ret = TAKE_PTR(s);
-        s = NULL;
 
         return 0;
 }

src/shared/path-lookup.c

@@ -181,7 +181,6 @@ static char** user_dirs(
         _cleanup_strv_free_ char **config_dirs = NULL, **data_dirs = NULL;
         _cleanup_free_ char *data_home = NULL;
         _cleanup_strv_free_ char **res = NULL;
-        char **tmp;
         int r;
 
         r = xdg_user_dirs(&config_dirs, &data_dirs);
@@ -242,10 +241,7 @@ static char** user_dirs(
         if (path_strv_make_absolute_cwd(res) < 0)
                 return NULL;
 
-        tmp = res;
+        return TAKE_PTR(res);
-        res = NULL;
-
-        return tmp;
 }
 
 bool path_is_user_data_dir(const char *path) {
@@ -374,8 +370,7 @@ static int acquire_config_dirs(UnitFileScope scope, char **persistent, char **ru
                         *runtime = NULL;
                 }
 
-                *persistent = a;
+                *persistent = TAKE_PTR(a);
-                a = NULL;
 
                 return 0;
 
@@ -413,8 +408,7 @@ static int acquire_control_dirs(UnitFileScope scope, char **persistent, char **r
                 if (!b)
                         return -ENOMEM;
 
-                *runtime = b;
+                *runtime = TAKE_PTR(b);
-                b = NULL;
 
                 break;
         }
@@ -443,8 +437,7 @@ static int acquire_control_dirs(UnitFileScope scope, char **persistent, char **r
                 assert_not_reached("Hmm, unexpected scope value.");
         }
 
-        *persistent = a;
+        *persistent = TAKE_PTR(a);
-        a = NULL;
 
         return 0;
 }

src/shared/specifier.c

@@ -117,8 +117,7 @@ int specifier_printf(const char *text, const Specifier table[], void *userdata,
                 *(t++) = '%';
 
         *t = 0;
-        *_ret = ret;
+        *_ret = TAKE_PTR(ret);
-        ret = NULL;
         return 0;
 }
 

src/systemctl/systemctl.c

@@ -1924,8 +1924,7 @@ static int get_machine_list(
                         return log_oom();
 
                 machine_infos[c].is_host = true;
-                machine_infos[c].name = hn;
+                machine_infos[c].name = TAKE_PTR(hn);
-                hn = NULL;
 
                 (void) get_machine_properties(bus, &machine_infos[c]);
                 c++;
@@ -2462,10 +2461,9 @@ static int unit_file_find_path(LookupPaths *lp, const char *unit_name, char **un
                 if (r < 0)
                         return log_error_errno(r, "Failed to access path '%s': %m", path);
 
-                if (unit_path) {
+                if (unit_path)
-                        *unit_path = lpath;
+                        *unit_path = TAKE_PTR(lpath);
-                        lpath = NULL;
+
-                }
                 return 1;
         }
 
@@ -2497,10 +2495,9 @@ static int unit_find_template_path(
         if (r < 0)
                 return r;
 
-        if (template) {
+        if (template)
-                *template = _template;
+                *template = TAKE_PTR(_template);
-                _template = NULL;
+
-        }
         return r;
 }
 
@@ -6671,8 +6668,7 @@ static int create_edit_temp_file(const char *new_path, const char *original_path
         } else if (r < 0)
                 return log_error_errno(r, "Failed to create temporary file for \"%s\": %m", new_path);
 
-        *ret_tmp_fn = t;
+        *ret_tmp_fn = TAKE_PTR(t);
-        t = NULL;
 
         return 0;
 }
@@ -6703,12 +6699,9 @@ static int get_file_to_edit(
                         return -EEXIST;
                 }
 
-                *ret_path = run;
+                *ret_path = TAKE_PTR(run);
-                run = NULL;
+        } else
-        } else {
+                *ret_path = TAKE_PTR(path);
-                *ret_path = path;
-                path = NULL;
-        }
 
         return 0;
 }

src/sysv-generator/sysv-generator.c

@@ -741,8 +741,7 @@ static int acquire_search_path(const char *def, const char *envvar, char ***ret)
         if (!path_strv_resolve_uniq(l, NULL))
                 return log_oom();
 
-        *ret = l;
+        *ret = TAKE_PTR(l);
-        l = NULL;
 
         return 0;
 }

src/tmpfiles/tmpfiles.c

@@ -310,8 +310,7 @@ static int user_config_paths(char*** ret) {
         if (r < 0)
                 return r;
 
-        *ret = res;
+        *ret = TAKE_PTR(res);
-        res = NULL;
         return 0;
 }
 

src/udev/net/ethtool-util.c

@@ -304,8 +304,7 @@ static int get_stringset(int fd, struct ifreq *ifr, int stringset_id, struct eth
         if (r < 0)
                 return -errno;
 
-        *gstrings = strings;
+        *gstrings = TAKE_PTR(strings);
-        strings = NULL;
 
         return 0;
 }

src/udev/udev-builtin-path_id.c

@@ -62,10 +62,8 @@ static void path_prepend(char **path, const char *fmt, ...) {
                 }
 
                 free_and_replace(*path, new);
-        } else {
+        } else
-                *path = pre;
+                *path = TAKE_PTR(pre);
-                pre = NULL;
-        }
 }
 
 /*

src/udev/udevd.c

@@ -233,8 +233,7 @@ static int worker_new(struct worker **ret, Manager *manager, struct udev_monitor
         if (r < 0)
                 return r;
 
-        *ret = worker;
+        *ret = TAKE_PTR(worker);
-        worker = NULL;
 
         return 0;
 }

src/vconsole/vconsole-setup.c

@@ -358,8 +358,7 @@ static int find_source_vc(char **ret_path, unsigned *ret_idx) {
 
                 /* all checks passed, return this one as a source console */
                 *ret_idx = i;
-                *ret_path = path;
+                *ret_path = TAKE_PTR(path);
-                path = NULL;
                 ret_fd = fd;
                 fd = -1;
                 return ret_fd;