core: implement per unit journal rate limiting

Add LogRateLimitIntervalSec= and LogRateLimitBurst= options for
services. If provided, these values get passed to the journald
client context, and those values are used in the rate limiting
function in the journal over the the journald.conf values.

Part of #10230

1 files changed, 48 insertions, 3 deletions

diff --git a/src/journal/journald-context.c b/src/journal/journald-context.c
index 8037480304..1f1603b376 100644
--- a/src/journal/journald-context.c
+++ b/src/journal/journald-context.c
@@ -13,6 +13,7 @@
 #include "io-util.h"
 #include "journal-util.h"
 #include "journald-context.h"
+#include "parse-util.h"
 #include "process-util.h"
 #include "string-util.h"
 #include "syslog-util.h"
@@ -102,6 +103,8 @@ static int client_context_new(Server *s, pid_t pid, ClientContext **ret) {
         c->timestamp = USEC_INFINITY;
         c->extra_fields_mtime = NSEC_INFINITY;
         c->log_level_max = -1;
+        c->log_rate_limit_interval = s->rate_limit_interval;
+        c->log_rate_limit_burst = s->rate_limit_burst;
 
         r = hashmap_put(s->client_contexts, PID_TO_PTR(pid), c);
         if (r < 0) {
@@ -113,7 +116,8 @@ static int client_context_new(Server *s, pid_t pid, ClientContext **ret) {
         return 0;
 }
 
-static void client_context_reset(ClientContext *c) {
+static void client_context_reset(Server *s, ClientContext *c) {
+        assert(s);
         assert(c);
 
         c->timestamp = USEC_INFINITY;
@@ -148,6 +152,9 @@ static void client_context_reset(ClientContext *c) {
         c->extra_fields_mtime = NSEC_INFINITY;
 
         c->log_level_max = -1;
+
+        c->log_rate_limit_interval = s->rate_limit_interval;
+        c->log_rate_limit_burst = s->rate_limit_burst;
 }
 
 static ClientContext* client_context_free(Server *s, ClientContext *c) {
@@ -161,7 +168,7 @@ static ClientContext* client_context_free(Server *s, ClientContext *c) {
         if (c->in_lru)
                 assert_se(prioq_remove(s->client_contexts_lru, c, &c->lru_index) >= 0);
 
-        client_context_reset(c);
+        client_context_reset(s, c);
 
         return mfree(c);
 }
@@ -424,6 +431,42 @@ static int client_context_read_extra_fields(
         return 0;
 }
 
+static int client_context_read_log_rate_limit_interval(ClientContext *c) {
+        _cleanup_free_ char *value = NULL;
+        const char *p;
+        int r;
+
+        assert(c);
+
+        if (!c->unit)
+                return 0;
+
+        p = strjoina("/run/systemd/units/log-rate-limit-interval:", c->unit);
+        r = readlink_malloc(p, &value);
+        if (r < 0)
+                return r;
+
+        return safe_atou64(value, &c->log_rate_limit_interval);
+}
+
+static int client_context_read_log_rate_limit_burst(ClientContext *c) {
+        _cleanup_free_ char *value = NULL;
+        const char *p;
+        int r;
+
+        assert(c);
+
+        if (!c->unit)
+                return 0;
+
+        p = strjoina("/run/systemd/units/log-rate-limit-burst:", c->unit);
+        r = readlink_malloc(p, &value);
+        if (r < 0)
+                return r;
+
+        return safe_atou(value, &c->log_rate_limit_burst);
+}
+
 static void client_context_really_refresh(
                 Server *s,
                 ClientContext *c,
@@ -450,6 +493,8 @@ static void client_context_really_refresh(
         (void) client_context_read_invocation_id(s, c);
         (void) client_context_read_log_level_max(s, c);
         (void) client_context_read_extra_fields(s, c);
+        (void) client_context_read_log_rate_limit_interval(c);
+        (void) client_context_read_log_rate_limit_burst(c);
 
         c->timestamp = timestamp;
 
@@ -480,7 +525,7 @@ void client_context_maybe_refresh(
         /* If the data isn't pinned and if the cashed data is older than the upper limit, we flush it out
          * entirely. This follows the logic that as long as an entry is pinned the PID reuse is unlikely. */
         if (c->n_ref == 0 && c->timestamp + MAX_USEC < timestamp) {
-                client_context_reset(c);
+                client_context_reset(s, c);
                 goto refresh;
         }