coredumpctl: allow to show coredump info in json format in dump and debug command

Previously `coredumpctl dump/debug` silently ignored --json= option.
Let's honor the option.

src/coredump/coredumpctl-core.c

@@ -180,7 +180,7 @@ int verb_dump_core(int argc, char *argv[], uintptr_t _data, void *userdata) {
                         return log_error_errno(errno, "Failed to open \"%s\" for writing: %m", arg_output);
         }
 
-        print_info(f ? stdout : stderr, j, false);
+        (void) print_entry(f ? stdout : stderr, j, /* need_space= */ false, /* table= */ NULL);
 
         r = save_core(j, f, NULL, NULL);
         if (r < 0)

src/coredump/coredumpctl-debugger.c

@@ -63,7 +63,7 @@ int verb_run_debug(int argc, char *argv[], uintptr_t _data, void *userdata) {
                 return r;
 
         if (!arg_quiet) {
-                print_info(stdout, j, false);
+                (void) print_entry(stdout, j, /* need_space= */ false, /* table= */ NULL);
                 fputs("\n", stdout);
         }
 

src/coredump/coredumpctl-info.c

@@ -330,7 +330,7 @@ static int coredump_fields_load(sd_journal *j, CoredumpFields *f) {
         return 0;
 }
 
-int print_info(FILE *file, sd_journal *j, bool need_space) {
+static int print_info(FILE *file, sd_journal *j, bool need_space) {
         _cleanup_(coredump_fields_done) CoredumpFields f = {
                 .disk_size = UINT64_MAX,
         };
@@ -598,14 +598,15 @@ static int print_info_json(FILE *file, sd_journal *j) {
         return 0;
 }
 
-int print_entry(sd_journal *j, size_t n_found, Table *t) {
+int print_entry(FILE *f, sd_journal *j, bool need_space, Table *table) {
+        assert(f);
         assert(j);
 
-        if (t)
-                return print_list(stdout, j, t);
+        if (table)
+                return print_list(f, j, table);
         if (arg_field)
-                return print_field(stdout, j);
+                return print_field(f, j);
         if (sd_json_format_enabled(arg_json_format_flags))
-                return print_info_json(stdout, j);
-        return print_info(stdout, j, n_found > 0);
+                return print_info_json(f, j);
+        return print_info(f, j, need_space);
 }

src/coredump/coredumpctl-info.h

@@ -3,5 +3,4 @@
 
 #include "forward.h"
 
-int print_info(FILE *file, sd_journal *j, bool need_space);
-int print_entry(sd_journal *j, size_t n_found, Table *t);
+int print_entry(FILE *f, sd_journal *j, bool need_space, Table *table);

src/coredump/coredumpctl-list.c

@@ -48,7 +48,7 @@ int verb_dump_list(int argc, char *argv[], uintptr_t _data, void *userdata) {
                 if (r < 0)
                         return r;
 
-                r = print_entry(j, 0, t);
+                r = print_entry(stdout, j, /* need_space= */ false, t);
                 if (r < 0)
                         return r;
         } else {
@@ -93,10 +93,12 @@ int verb_dump_list(int argc, char *argv[], uintptr_t _data, void *userdata) {
                                         break;
                         }
 
-                        r = print_entry(j, n_found++, t);
+                        r = print_entry(stdout, j, /* need_space= */ n_found > 0, t);
                         if (r < 0)
                                 return r;
 
+                        n_found++;
+
                         if (arg_rows_max != SIZE_MAX && n_found >= arg_rows_max)
                                 break;
                 }