hashmap: make sure hashmap_get_strv()+set_get_strv() work with a NULL object

Before we invoke n_entries() we need to check for non-NULL here, like in
all other calls to the helper function. Otherwise we'll crash when
invoked with a NULL object, which we usually consider equivalent to an
empty one though.

src/basic/hashmap.c

@@ -1761,6 +1761,9 @@ char** _hashmap_get_strv(HashmapBase *h) {
         Iterator i;
         unsigned idx, n;
 
+        if (!h)
+                return new0(char*, 1);
+
         sv = new(char*, n_entries(h)+1);
         if (!sv)
                 return NULL;

src/coredump/coredumpctl.c

@@ -150,7 +150,7 @@ static int acquire_journal(sd_journal **ret, char **matches) {
         return 0;
 }
 
-static int help(void) {
+static int verb_help(int argc, char **argv, void *userdata) {
         _cleanup_free_ char *link = NULL;
         int r;
 
@@ -232,7 +232,7 @@ static int parse_argv(int argc, char *argv[]) {
         while ((c = getopt_long(argc, argv, "hA:o:F:1D:rS:U:qn:", options, NULL)) >= 0)
                 switch(c) {
                 case 'h':
-                        return help();
+                        return verb_help(0, NULL, NULL);
 
                 case ARG_VERSION:
                         return version();
@@ -1242,6 +1242,7 @@ static int coredumpctl_main(int argc, char *argv[]) {
                 { "dump",  VERB_ANY, VERB_ANY, 0,            dump_core },
                 { "debug", VERB_ANY, VERB_ANY, 0,            run_debug },
                 { "gdb",   VERB_ANY, VERB_ANY, 0,            run_debug },
+                { "help",  VERB_ANY, 1,        0,            verb_help },
                 {}
         };
 

src/udev/udev-builtin-blkid.c

@@ -114,7 +114,7 @@ static int find_gpt_root(sd_device *dev, blkid_probe pr, bool test) {
 
 #if defined(GPT_ROOT_NATIVE) && ENABLE_EFI
 
-        _cleanup_free_ char *root_id = NULL;
+        _cleanup_free_ char *root_id = NULL, *root_label = NULL;
         bool found_esp = false;
         blkid_partlist pl;
         int i, nvals, r;
@@ -133,7 +133,7 @@ static int find_gpt_root(sd_device *dev, blkid_probe pr, bool test) {
         nvals = blkid_partlist_numof_partitions(pl);
         for (i = 0; i < nvals; i++) {
                 blkid_partition pp;
-                const char *stype, *sid;
+                const char *stype, *sid, *label;
                 sd_id128_t type;
 
                 pp = blkid_partlist_get_partition(pl, i);
@@ -144,6 +144,8 @@ static int find_gpt_root(sd_device *dev, blkid_probe pr, bool test) {
                 if (!sid)
                         continue;
 
+                label = blkid_partition_get_name(pp); /* returns NULL if empty */
+
                 stype = blkid_partition_get_type_string(pp);
                 if (!stype)
                         continue;
@@ -174,13 +176,17 @@ static int find_gpt_root(sd_device *dev, blkid_probe pr, bool test) {
                         if (flags & GPT_FLAG_NO_AUTO)
                                 continue;
 
-                        /* We found a suitable root partition, let's
-                         * remember the first one. */
+                        /* We found a suitable root partition, let's remember the first one, or the one with
+                         * the newest version, as determined by comparing the partition labels. */
 
-                        if (!root_id) {
-                                root_id = strdup(sid);
-                                if (!root_id)
-                                        return -ENOMEM;
+                        if (!root_id || strverscmp_improved(label, root_label) > 0) {
+                                r = free_and_strdup(&root_id, sid);
+                                if (r < 0)
+                                        return r;
+
+                                r = free_and_strdup(&root_label, label);
+                                if (r < 0)
+                                        return r;
                         }
                 }
         }

units/final.target

@@ -8,7 +8,7 @@
 #  (at your option) any later version.
 
 [Unit]
-Description=Late Boot Services
+Description=Late Shutdown Services
 Documentation=man:systemd.special(7)
 DefaultDependencies=no
 RefuseManualStart=yes