journalctl: Accept globs in --{exclude-,}identifier=

--unit= has accepted globs for a long time, let's bring --identifier= up
to parity.

Closes: #20457

man/journalctl.xml

@@ -395,6 +395,10 @@
 
         <para>This parameter can be specified multiple times.</para>
 
+        <para>If the argument contains a shell-style glob, it is matched against the syslog identifiers
+        actually present in the journal, as for <option>--unit=</option>. If no glob matches anything, and
+        no exact identifier was given either, an error is returned.</para>
+
         <xi:include href="version-info.xml" xpointer="v217"/></listitem>
       </varlistentry>
 
@@ -407,6 +411,10 @@
 
         <para>This parameter can be specified multiple times.</para>
 
+        <para>If the argument contains a shell-style glob, it is matched against the syslog identifiers
+        actually present in the journal, as for <option>--identifier=</option>. Patterns which do not match
+        anything are silently skipped.</para>
+
         <xi:include href="version-info.xml" xpointer="v256"/></listitem>
       </varlistentry>
 

src/journal/journalctl-filter.c

@@ -133,7 +133,7 @@ int journal_add_unit_matches(
         if (!strv_isempty(patterns)) {
                 _cleanup_set_free_ Set *units = NULL;
 
-                r = get_possible_units(j, SYSTEM_UNITS_FULL, patterns, &units);
+                r = get_possible_field_values(j, SYSTEM_UNITS_FULL, patterns, &units);
                 if (r < 0)
                         return r;
 
@@ -176,7 +176,7 @@ int journal_add_unit_matches(
         if (!strv_isempty(patterns)) {
                 _cleanup_set_free_ Set *units = NULL;
 
-                r = get_possible_units(j, USER_UNITS_FULL, patterns, &units);
+                r = get_possible_field_values(j, USER_UNITS_FULL, patterns, &units);
                 if (r < 0)
                         return r;
 
@@ -217,6 +217,8 @@ static int add_units(sd_journal *j) {
 }
 
 static int add_syslog_identifier(sd_journal *j) {
+        _cleanup_strv_free_ char **patterns = NULL;
+        bool added = false;
         int r;
 
         assert(j);
@@ -225,26 +227,83 @@ static int add_syslog_identifier(sd_journal *j) {
                 return 0;
 
         STRV_FOREACH(i, arg_syslog_identifier) {
+                if (string_is_glob(*i)) {
+                        r = strv_extend(&patterns, *i);
+                        if (r < 0)
+                                return r;
+                        continue;
+                }
+
                 r = journal_add_match_pair(j, "SYSLOG_IDENTIFIER", *i);
                 if (r < 0)
                         return r;
                 r = sd_journal_add_disjunction(j);
                 if (r < 0)
                         return r;
+                added = true;
         }
 
+        if (!strv_isempty(patterns)) {
+                _cleanup_set_free_ Set *identifiers = NULL;
+
+                r = get_possible_field_values(j, "SYSLOG_IDENTIFIER\0", patterns, &identifiers);
+                if (r < 0)
+                        return r;
+
+                const char *id;
+                SET_FOREACH(id, identifiers) {
+                        r = journal_add_match_pair(j, "SYSLOG_IDENTIFIER", id);
+                        if (r < 0)
+                                return r;
+                        r = sd_journal_add_disjunction(j);
+                        if (r < 0)
+                                return r;
+                        added = true;
+                }
+        }
+
+        /* Complain if the user asked for identifiers but nothing whatsoever was found, since otherwise
+         * everything would be matched. Same as for --unit=. */
+        if (!added)
+                return -ENODATA;
+
         return sd_journal_add_conjunction(j);
 }
 
 static int add_exclude_identifier(sd_journal *j) {
+        _cleanup_strv_free_ char **patterns = NULL;
         _cleanup_set_free_ Set *excludes = NULL;
         int r;
 
         assert(j);
 
-        r = set_put_strdupv(&excludes, arg_exclude_identifier);
-        if (r < 0)
-                return r;
+        STRV_FOREACH(i, arg_exclude_identifier) {
+                if (string_is_glob(*i)) {
+                        r = strv_extend(&patterns, *i);
+                        if (r < 0)
+                                return r;
+                        continue;
+                }
+
+                r = set_put_strdup(&excludes, *i);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!strv_isempty(patterns)) {
+                _cleanup_set_free_ Set *found = NULL;
+
+                r = get_possible_field_values(j, "SYSLOG_IDENTIFIER\0", patterns, &found);
+                if (r < 0)
+                        return r;
+
+                const char *id;
+                SET_FOREACH(id, found) {
+                        r = set_put_strdup(&excludes, id);
+                        if (r < 0)
+                                return r;
+                }
+        }
 
         return set_free_and_replace(j->exclude_syslog_identifiers, excludes);
 }

src/journal/journalctl-util.c

@@ -128,7 +128,7 @@ int journal_acquire_boot(sd_journal *j) {
         return 1;
 }
 
-int get_possible_units(
+int get_possible_field_values(
                 sd_journal *j,
                 const char *fields,
                 char * const *patterns,
@@ -163,10 +163,12 @@ int get_possible_units(
                                 return -ENOMEM;
 
                         size_t i;
-                        if (!strv_fnmatch_full(patterns, u, FNM_NOESCAPE, &i))
+                        /* Unlike unit names, values such as SYSLOG_IDENTIFIER= may legitimately contain
+                         * '*', '?' or '[', so an exact match must count too. */
+                        if (!strv_fnmatch_full(patterns, u, FNM_NOESCAPE, &i) && !strv_contains(patterns, u))
                                 continue;
 
-                        log_debug("Matched %s with pattern %s=%s", u, field, patterns[i]);
+                        log_debug("Matched %s with pattern %s=%s", u, field, i == SIZE_MAX ? u : patterns[i]);
                         r = set_ensure_consume(&found, &string_hash_ops_free, TAKE_PTR(u));
                         if (r < 0)
                                 return r;
@@ -215,7 +217,7 @@ int acquire_unit(sd_journal *j, const char *option_name, const char **ret_unit,
         if (string_is_glob(u)) {
                 _cleanup_set_free_ Set *s = NULL;
 
-                r = get_possible_units(j, type == LOG_SYSTEM_UNIT_INVOCATION_ID ? SYSTEM_UNITS : USER_UNITS,
+                r = get_possible_field_values(j, type == LOG_SYSTEM_UNIT_INVOCATION_ID ? SYSTEM_UNITS : USER_UNITS,
                                        STRV_MAKE(u), &s);
                 if (r < 0)
                         return log_error_errno(r, "Failed to get matching unit '%s' from journal: %m", u);

src/journal/journalctl-util.h

@@ -30,6 +30,6 @@ char* format_timestamp_maybe_utc(char *buf, size_t l, usec_t t);
 int acquire_journal(sd_journal **ret);
 bool journal_boot_has_effect(sd_journal *j);
 int journal_acquire_boot(sd_journal *j);
-int get_possible_units(sd_journal *j, const char *fields, char * const *patterns, Set **ret);
+int get_possible_field_values(sd_journal *j, const char *fields, char * const *patterns, Set **ret);
 int acquire_unit(sd_journal *j, const char *option_name, const char **ret_unit, LogIdType *ret_type);
 int journal_acquire_invocation(sd_journal *j);