tree-wide: (void)ify a few unlink() and rmdir()

Let's be helpful to static analyzers which care about whether we
knowingly ignore return values. We do in these cases, since they are
usually part of error paths.

src/backlight/backlight.c

@@ -412,7 +412,7 @@ static int run(int argc, char *argv[]) {
                 const char *value;
 
                 if (validate_device(device) == 0) {
-                        unlink(saved);
+                        (void) unlink(saved);
                         return 0;
                 }
 

src/core/namespace.c

@@ -1674,8 +1674,8 @@ int setup_tmp_dirs(const char *id, char **tmp_dir, char **var_tmp_dir) {
                 char *t;
 
                 t = strjoina(a, "/tmp");
-                rmdir(t);
-                rmdir(a);
+                (void) rmdir(t);
+                (void) rmdir(a);
 
                 free(a);
                 return r;

src/coredump/coredumpctl.c

@@ -859,7 +859,7 @@ static int save_core(sd_journal *j, FILE *file, char **path, bool *unlink_temp)
 
 error:
         if (temp) {
-                unlink(temp);
+                (void) unlink(temp);
                 log_debug("Removed temporary file %s", temp);
         }
         return r;
@@ -985,7 +985,7 @@ finish:
 
         if (unlink_path) {
                 log_debug("Removed temporary file %s", path);
-                unlink(path);
+                (void) unlink(path);
         }
 
         return r;

src/import/import-raw.c

@@ -183,7 +183,7 @@ static int raw_import_maybe_convert_qcow2(RawImport *i) {
 
         r = qcow2_convert(i->output_fd, converted_fd);
         if (r < 0) {
-                unlink(t);
+                (void) unlink(t);
                 return log_error_errno(r, "Failed to convert qcow2 image: %m");
         }
 

src/import/pull-raw.c

@@ -250,7 +250,7 @@ static int raw_pull_maybe_convert_qcow2(RawPull *i) {
 
         r = qcow2_convert(i->raw_job->disk_fd, converted_fd);
         if (r < 0) {
-                unlink(t);
+                (void) unlink(t);
                 return log_error_errno(r, "Failed to convert qcow2 image: %m");
         }
 
@@ -364,7 +364,7 @@ static int raw_pull_make_local_copy(RawPull *i) {
 
         r = copy_bytes(i->raw_job->disk_fd, dfd, (uint64_t) -1, COPY_REFLINK);
         if (r < 0) {
-                unlink(tp);
+                (void) unlink(tp);
                 return log_error_errno(r, "Failed to make writable copy of image: %m");
         }
 
@@ -376,7 +376,7 @@ static int raw_pull_make_local_copy(RawPull *i) {
         r = rename(tp, p);
         if (r < 0)  {
                 r = log_error_errno(errno, "Failed to move writable image into place: %m");
-                unlink(tp);
+                (void) unlink(tp);
                 return r;
         }
 

src/journal-remote/journal-upload.c

@@ -106,7 +106,7 @@ static int check_cursor_updating(Uploader *u) {
         if (r < 0)
                 return log_error_errno(r, "Cannot save state to %s: %m",
                                        u->state_file);
-        unlink(temp_path);
+        (void) unlink(temp_path);
 
         return 0;
 }

src/journal/journalctl.c

@@ -1841,7 +1841,7 @@ finish:
         safe_close(fd);
 
         if (k) {
-                unlink(k);
+                (void) unlink(k);
                 free(k);
         }
 

src/libsystemd/sd-hwdb/hwdb-util.c

@@ -434,7 +434,7 @@ static int trie_store(struct trie *trie, const char *filename, bool compat) {
  error_fclose:
         r = -errno;
         fclose(t.f);
-        unlink(filename_tmp);
+        (void) unlink(filename_tmp);
         return r;
 }
 

src/login/logind-inhibit.c

@@ -59,7 +59,7 @@ void inhibitor_free(Inhibitor *i) {
         free(i->why);
 
         if (i->state_file) {
-                unlink(i->state_file);
+                (void) unlink(i->state_file);
                 free(i->state_file);
         }
 
@@ -173,7 +173,7 @@ int inhibitor_stop(Inhibitor *i) {
                           inhibit_mode_to_string(i->mode));
 
         if (i->state_file)
-                unlink(i->state_file);
+                (void) unlink(i->state_file);
 
         i->started = false;
 
@@ -320,7 +320,7 @@ void inhibitor_remove_fifo(Inhibitor *i) {
         i->fifo_fd = safe_close(i->fifo_fd);
 
         if (i->fifo_path) {
-                unlink(i->fifo_path);
+                (void) unlink(i->fifo_path);
                 i->fifo_path = mfree(i->fifo_path);
         }
 }

src/network/networkd-link.c

@@ -4018,7 +4018,7 @@ int link_save(Link *link) {
         assert(link->manager);
 
         if (link->state == LINK_STATE_LINGER) {
-                unlink(link->state_file);
+                (void) unlink(link->state_file);
                 return 0;
         }
 
@@ -4287,7 +4287,7 @@ int link_save(Link *link) {
                         "DHCP_LEASE=%s\n",
                         link->lease_file);
         } else
-                unlink(link->lease_file);
+                (void) unlink(link->lease_file);
 
         if (link->ipv4ll) {
                 struct in_addr address;

src/sysusers/sysusers.c

@@ -244,7 +244,7 @@ static int make_backup(const char *target, const char *x) {
         return 0;
 
 fail:
-        unlink(temp);
+        (void) unlink(temp);
         return r;
 }