journalctl: allow to dump generated key in json format

Closes #35503.

man/journalctl.xml

@@ -835,6 +835,9 @@
         with <option>--setup-keys</option>. Shorter intervals increase CPU consumption but shorten the time
         range of undetectable journal alterations. Defaults to 15min.</para>
 
+        <para>Note, <option>--output=json-sse</option> and <option>--output=json-seq</option> are silently
+        migrated to <option>--output=json</option>.</para>
+
         <xi:include href="version-info.xml" xpointer="v189"/></listitem>
       </varlistentry>
 

src/journal/journalctl-authenticate.c

@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include "sd-json.h"
+
 #include "ansi-color.h"
 #include "chattr-util.h"
 #include "errno-util.h"
@@ -158,7 +160,7 @@ int action_setup_keys(void) {
         if (r < 0)
                 return r;
 
-        if (!on_tty() || arg_quiet) {
+        if ((!on_tty() || arg_quiet) && !sd_json_format_enabled(arg_json_format_flags)) {
                 /* If we are not on a TTY, show only the key. */
                 puts(key);
                 return 0;
@@ -169,6 +171,32 @@ int action_setup_keys(void) {
         if (hn)
                 hostname_cleanup(hn);
 
+        if (sd_json_format_enabled(arg_json_format_flags)) {
+                _cleanup_(sd_json_variant_unrefp) sd_json_variant *v = NULL;
+
+                if (arg_json_format_flags & (SD_JSON_FORMAT_SSE | SD_JSON_FORMAT_SEQ)) {
+                        log_debug("Specified --output=%s with --setup-keys, migrating to --output=json.",
+                                  FLAGS_SET(arg_json_format_flags, SD_JSON_FORMAT_SSE) ? "json-sse" : "json-seq");
+                        arg_json_format_flags &= ~(SD_JSON_FORMAT_SSE | SD_JSON_FORMAT_SEQ);
+                        arg_json_format_flags |= SD_JSON_FORMAT_NEWLINE;
+                }
+
+                r = sd_json_buildo(
+                                &v,
+                                SD_JSON_BUILD_PAIR_ID128("machine", machine),
+                                SD_JSON_BUILD_PAIR_STRING("hostname", hn),
+                                SD_JSON_BUILD_PAIR_STRING("path", path),
+                                SD_JSON_BUILD_PAIR_STRING("key", key));
+                if (r < 0)
+                        return log_error_errno(r, "Failed to build json object: %m");
+
+                r = sd_json_variant_dump(v, arg_json_format_flags, /* f = */ NULL, /* prefix = */ NULL);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to dump json object: %m");
+
+                return 0;
+        }
+
         fprintf(stderr,
                 "\nNew keys have been generated for host %s%s" SD_ID128_FORMAT_STR ".\n"
                 "\n"

test/units/TEST-04-JOURNAL.fss.sh

@@ -10,6 +10,11 @@ if ! journalctl --version | grep -qF +GCRYPT; then
     exit 0
 fi
 
+# output key and related info in json format
+for mode in json json-pretty json-seq json-sse; do
+    journalctl --force --setup-keys --interval=2 --output="$mode" | jq . >/dev/null
+done
+
 # without --quiet, should be effectively equivalent to the below, as we are not on tty
 journalctl --force --setup-keys --interval=2