Hi,
> 1) Start reload_db() in a background thread, resume scanning, and call
> back once the new engine is in place; then exchange the pointers
> from old to new engine and free the old one.
FWIW, I have implemented this option, and it seems to work just fine.
Patch is pasted below.
Do you see any problems with this approach?
Julius
--
From 56e376e55db86571e50737cf20a33b8716cad291 Mon Sep 17 00:00:00 2001
From: Julius Plenz <plenz@cis.fu-berlin.de>
Date: Mon, 7 Apr 2014 19:21:44 +0200
Subject: [PATCH] Reload virus definition in separate thread, eliminating delay
This implements option #1 of
http://lurker.clamav.net/message/20140407.145009.12f41a68.en.html We introduce a daemon-global "reload_engine" pointer, also protected
under the reload_mutex. Instead of calling reload_db() syncronously, we
dispatch a thread that will eventually write to the reload_engine
pointer, signaling that the new engine is fully set up. Then, under
protection of the mutex, the current engine is exchanged and the old
engine freed.
---
clamd/server-th.c | 120 +++++++++++++++++++++++++++++-------------------------
clamd/server.h | 7 ++++
2 files changed, 71 insertions(+), 56 deletions(-)
diff --git a/clamd/server-th.c b/clamd/server-th.c
index 86a3a48..9afa2b7 100644
--- a/clamd/server-th.c
+++ b/clamd/server-th.c
@@ -64,6 +64,7 @@
int progexit = 0;
pthread_mutex_t exit_mutex = PTHREAD_MUTEX_INITIALIZER;
int reload = 0;
+struct cl_engine *reload_engine = NULL;
time_t reloaded_time = 0;
pthread_mutex_t reload_mutex = PTHREAD_MUTEX_INITIALIZER;
int sighup = 0;
@@ -158,40 +159,27 @@ void sighandler_th(int sig)
logg("$Failed to write to syncpipe\n");
}
-static struct cl_engine *reload_db(struct cl_engine *engine, unsigned int dboptions, const struct optstruct *opts, int do_check, int *ret)
+static void *reload_db(void *argp)
{
const char *dbdir;
int retval;
unsigned int sigs = 0;
struct cl_settings *settings = NULL;
+ struct cl_engine *engine = NULL;
- *ret = 0;
- if(do_check) {
- if(!dbstat.entries) {
- logg("No stats for Database check - forcing reload\n");
- return engine;
- }
-
- if(cl_statchkdir(&dbstat) == 1) {
- logg("SelfCheck: Database modification detected. Forcing reload.\n");
- return engine;
- } else {
- logg("SelfCheck: Database status OK.\n");
- return NULL;
- }
- }
+ struct reload_db_args *args = (struct reload_db_args *)argp;
+ struct cl_engine *oldengine = args->engine;
+ unsigned int dboptions = args->dboptions;
+ const struct optstruct *opts = args->opts;
- /* release old structure */
- if(engine) {
+ if(oldengine) {
/* copy current settings */
- settings = cl_engine_settings_copy(engine);
+ settings = cl_engine_settings_copy(oldengine);
if(!settings)
logg("^Can't make a copy of the current engine settings\n");
-
- thrmgr_setactiveengine(NULL);
- cl_engine_free(engine);
}
+
dbdir = optget(opts, "DatabaseDirectory")->strarg;
logg("Reading databases from %s\n", dbdir);
@@ -201,18 +189,16 @@ static struct cl_engine *reload_db(struct cl_engine *engine, unsigned int dbopti
memset(&dbstat, 0, sizeof(struct cl_stat));
if((retval = cl_statinidir(dbdir, &dbstat))) {
logg("!cl_statinidir() failed: %s\n", cl_strerror(retval));
- *ret = 1;
if(settings)
cl_engine_settings_free(settings);
- return NULL;
+ return;
}
if(!(engine = cl_engine_new())) {
logg("!Can't initialize antivirus engine\n");
- *ret = 1;
if(settings)
cl_engine_settings_free(settings);
- return NULL;
+ return;
}
if(settings) {
@@ -227,20 +213,20 @@ static struct cl_engine *reload_db(struct cl_engine *engine, unsigned int dbopti
if((retval = cl_load(dbdir, engine, &sigs, dboptions))) {
logg("!reload db failed: %s\n", cl_strerror(retval));
cl_engine_free(engine);
- *ret = 1;
- return NULL;
+ return;
}
if((retval = cl_engine_compile(engine)) != 0) {
logg("!Database initialization error: can't compile engine: %s\n", cl_strerror(retval));
cl_engine_free(engine);
- *ret = 1;
- return NULL;
+ return;
}
logg("Database correctly reloaded (%u signatures)\n", sigs);
- thrmgr_setactiveengine(engine);
- return engine;
+ pthread_mutex_lock(&reload_mutex);
+ time(&reloaded_time);
+ reload_engine = engine;
+ pthread_mutex_unlock(&reload_mutex);
}
/*
@@ -713,6 +699,7 @@ int recvloop_th(int *socketds, unsigned nsockets, struct cl_engine *engine, unsi
unsigned long long val;
size_t i, j, rr_last = 0;
pthread_t accept_th;
+ pthread_t reload_th;
pthread_mutex_t fds_mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_mutex_t recvfds_mutex = PTHREAD_MUTEX_INITIALIZER;
struct acceptdata acceptdata = ACCEPTDATA_INIT(&fds_mutex, &recvfds_mutex);
@@ -1347,10 +1334,20 @@ int recvloop_th(int *socketds, unsigned nsockets, struct cl_engine *engine, unsi
if(selfchk) {
time(¤t_time);
if((current_time - start_time) >= (time_t)selfchk) {
- if(reload_db(engine, dboptions, opts, TRUE, &ret)) {
+ if(!dbstat.entries) {
+ logg("No stats for Database check - forcing reload\n");
+ pthread_mutex_lock(&reload_mutex);
+ reload = 1;
+ pthread_mutex_unlock(&reload_mutex);
+ }
+
+ if(cl_statchkdir(&dbstat) == 1) {
+ logg("SelfCheck: Database modification detected. Forcing reload.\n");
pthread_mutex_lock(&reload_mutex);
reload = 1;
pthread_mutex_unlock(&reload_mutex);
+ } else {
+ logg("SelfCheck: Database status OK.\n");
}
time(&start_time);
}
@@ -1360,34 +1357,45 @@ int recvloop_th(int *socketds, unsigned nsockets, struct cl_engine *engine, unsi
pthread_mutex_lock(&reload_mutex);
if(reload) {
pthread_mutex_unlock(&reload_mutex);
-#if defined(FANOTIFY) || defined(CLAMAUTH)
- if(optget(opts, "ScanOnAccess")->enabled && tharg) {
- logg("Restarting on-access scan\n");
- pthread_kill(fan_pid, SIGUSR1);
- pthread_join(fan_pid, NULL);
- }
-#endif
- engine = reload_db(engine, dboptions, opts, FALSE, &ret);
- if(ret) {
- logg("Terminating because of a fatal error.\n");
- if(new_sd >= 0)
- closesocket(new_sd);
- break;
- }
-
+ struct reload_db_args reload_db_args = {
+ .engine = engine,
+ .dboptions = dboptions,
+ .opts = opts,
+ };
pthread_mutex_lock(&reload_mutex);
reload = 0;
- time(&reloaded_time);
+ pthread_create(&reload_th, NULL, reload_db, &reload_db_args);
pthread_mutex_unlock(&reload_mutex);
+ } else {
+ if(reload_engine != NULL) {
#if defined(FANOTIFY) || defined(CLAMAUTH)
- if(optget(opts, "ScanOnAccess")->enabled && tharg) {
- tharg->engine = engine;
- pthread_create(&fan_pid, &fan_attr, fan_th, tharg);
- }
+ pthread_mutex_unlock(&reload_mutex);
+ if(optget(opts, "ScanOnAccess")->enabled && tharg) {
+ logg("Restarting on-access scan\n");
+ pthread_kill(fan_pid, SIGUSR1);
+ pthread_join(fan_pid, NULL);
+ }
+ pthread_mutex_lock(&reload_mutex);
#endif
- time(&start_time);
- } else {
- pthread_mutex_unlock(&reload_mutex);
+ static struct cl_engine *tmp;
+ tmp = engine;
+ engine = reload_engine;
+ thrmgr_setactiveengine(engine);
+ time(&start_time);
+ reload_engine = NULL;
+ pthread_mutex_unlock(&reload_mutex);
+
+ cl_engine_free(tmp);
+
+#if defined(FANOTIFY) || defined(CLAMAUTH)
+ if(optget(opts, "ScanOnAccess")->enabled && tharg) {
+ tharg->engine = engine;
+ pthread_create(&fan_pid, &fan_attr, fan_th, tharg);
+ }
+#endif
+ } else {
+ pthread_mutex_unlock(&reload_mutex);
+ }
}
}
diff --git a/clamd/server.h b/clamd/server.h
index bc2a296..e171ea9 100644
--- a/clamd/server.h
+++ b/clamd/server.h
@@ -46,6 +46,13 @@ struct thrwarg {
unsigned int options;
};
+/* reload_db arguments */
+struct reload_db_args {
+ struct cl_engine *engine;
+ unsigned int dboptions;
+ const struct optstruct *opts;
+};
+
int recvloop_th(int *socketds, unsigned nsockets, struct cl_engine *engine, unsigned int dboptions, const struct optstruct *opts);
void sighandler(int sig);
void sighandler_th(int sig);
--
1.9.0-zedat
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