journal: implement message catalog

The message catalog can be used to attach short help texts to log lines,
keyed by their MESSAGE_ID= fields. This is useful to help the
administrator understand the context and cause of a message, find
possible solutions and find further related documentation.

Since this is keyed off MESSAGE_ID= this will only work for native
journal messages.

The message catalog supports i18n, and is useful to augment english
language system messages with explanations in the local language.

This commit only includes short explanatory messages for a few example
message IDs, we'll add more complete documentation for the relevant
systemd messages later on.

1 files changed, 38 insertions, 3 deletions

diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c
index 011a11b70b..46a7be20ce 100644
--- a/src/journal/journalctl.c
+++ b/src/journal/journalctl.c
@@ -51,6 +51,7 @@
 #include "journal-qrcode.h"
 #include "fsprg.h"
 #include "unit-name.h"
+#include "catalog.h"
 
 #define DEFAULT_FSS_INTERVAL_USEC (15*USEC_PER_MINUTE)
 
@@ -74,6 +75,7 @@ static usec_t arg_since, arg_until;
 static bool arg_since_set = false, arg_until_set = false;
 static const char *arg_unit = NULL;
 static const char *arg_field = NULL;
+static bool arg_catalog = false;
 
 static enum {
         ACTION_SHOW,
@@ -82,6 +84,8 @@ static enum {
         ACTION_SETUP_KEYS,
         ACTION_VERIFY,
         ACTION_DISK_USAGE,
+        ACTION_LIST_CATALOG,
+        ACTION_UPDATE_CATALOG
 } arg_action = ACTION_SHOW;
 
 static int help(void) {
@@ -100,6 +104,7 @@ static int help(void) {
                "     --no-tail           Show all lines, even in follow mode\n"
                "  -o --output=STRING     Change journal output mode (short, short-monotonic,\n"
                "                         verbose, export, json, json-pretty, json-sse, cat)\n"
+               "  -x --catalog           Add message explanations where available\n"
                "  -a --all               Show all fields, including long and unprintable\n"
                "  -q --quiet             Don't show privilege warning\n"
                "     --no-pager          Do not pipe output into a pager\n"
@@ -116,6 +121,8 @@ static int help(void) {
                "     --header            Show journal header information\n"
                "     --disk-usage        Show total disk usage\n"
                "  -F --field=FIELD       List all values a certain field takes\n"
+               "     --list-catalog      Show message IDs of all entries in the message catalog\n"
+               "     --update-catalog    Update the message catalog database\n"
 #ifdef HAVE_GCRYPT
                "     --setup-keys        Generate new FSS key pair\n"
                "     --verify            Verify journal file consistency\n"
@@ -139,7 +146,9 @@ static int parse_argv(int argc, char *argv[]) {
                 ARG_VERIFY_KEY,
                 ARG_DISK_USAGE,
                 ARG_SINCE,
-                ARG_UNTIL
+                ARG_UNTIL,
+                ARG_LIST_CATALOG,
+                ARG_UPDATE_CATALOG
         };
 
         static const struct option options[] = {
@@ -168,6 +177,9 @@ static int parse_argv(int argc, char *argv[]) {
                 { "until",        required_argument, NULL, ARG_UNTIL        },
                 { "unit",         required_argument, NULL, 'u'              },
                 { "field",        required_argument, NULL, 'F'              },
+                { "catalog",      no_argument,       NULL, 'x'              },
+                { "list-catalog", no_argument,       NULL, ARG_LIST_CATALOG },
+                { "update-catalog",no_argument,      NULL, ARG_UPDATE_CATALOG },
                 { NULL,           0,                 NULL, 0                }
         };
 
@@ -176,7 +188,7 @@ static int parse_argv(int argc, char *argv[]) {
         assert(argc >= 0);
         assert(argv);
 
-        while ((c = getopt_long(argc, argv, "hfo:an::qmbD:p:c:u:F:", options, NULL)) >= 0) {
+        while ((c = getopt_long(argc, argv, "hfo:an::qmbD:p:c:u:F:x", options, NULL)) >= 0) {
 
                 switch (c) {
 
@@ -376,6 +388,18 @@ static int parse_argv(int argc, char *argv[]) {
                         arg_field = optarg;
                         break;
 
+                case 'x':
+                        arg_catalog = true;
+                        break;
+
+                case ARG_LIST_CATALOG:
+                        arg_action = ACTION_LIST_CATALOG;
+                        break;
+
+                case ARG_UPDATE_CATALOG:
+                        arg_action = ACTION_UPDATE_CATALOG;
+                        break;
+
                 default:
                         log_error("Unknown option code %c", c);
                         return -EINVAL;
@@ -841,6 +865,16 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
+        if (arg_action == ACTION_LIST_CATALOG)  {
+                r = catalog_list(stdout);
+                goto finish;
+        }
+
+        if (arg_action == ACTION_UPDATE_CATALOG)  {
+                r = catalog_update();
+                goto finish;
+        }
+
         r = access_check();
         if (r < 0)
                 goto finish;
@@ -1030,7 +1064,8 @@ int main(int argc, char *argv[]) {
                         flags =
                                 arg_all * OUTPUT_SHOW_ALL |
                                 (!on_tty() || pager_have()) * OUTPUT_FULL_WIDTH |
-                                on_tty() * OUTPUT_COLOR;
+                                on_tty() * OUTPUT_COLOR |
+                                arg_catalog * OUTPUT_CATALOG;
 
                         r = output_journal(stdout, j, arg_output, 0, flags);
                         if (r < 0)