#include <string.h> #include <stdlib.h> #include <pthread.h> #include "md5.h" #include "mpool.h" #include "clamav.h" #include "cache.h" #include "fmap.h" #if HAVE_CONFIG_H #include "clamav-config.h" #endif #define CACHE_PERTURB 10 /* 1/10th */ static mpool_t *mempool = NULL; static struct CACHE { struct CACHE_ENTRY { unsigned char hash[15]; uint32_t dbver; uint32_t hits; } *items; pthread_mutex_t mutex; uint32_t lastdb; } *cache = NULL; static unsigned int cache_entries = 0; int cl_cache_init(unsigned int entries) { unsigned int i; if(!(mempool = mpool_create())) { cli_errmsg("mpool init fail\n"); return 1; } if(!(cache = mpool_malloc(mempool, sizeof(struct CACHE) * 256))) { cli_errmsg("mpool malloc fail\n"); mpool_destroy(mempool); return 1; } for(i=0; i<256; i++) { struct CACHE_ENTRY *e = mpool_calloc(mempool, sizeof(struct CACHE_ENTRY), entries); if(!e) { cli_errmsg("mpool calloc fail\n"); mpool_destroy(mempool); return 1; } cache[i].items = e; cache[i].lastdb = 0; if(pthread_mutex_init(&cache[i].mutex, NULL)) { cli_errmsg("mutex init fail\n"); mpool_destroy(mempool); return 1; } } cache_entries = entries; return 0; } void cache_swap(struct CACHE_ENTRY *e, unsigned int a) { struct CACHE_ENTRY t; unsigned int b = a-1; if(!a || e[a].hits <= e[b].hits) return; do { if(e[a].hits > e[b].hits) continue; break; } while(b--); b++; memcpy(&t, &e[a], sizeof(t)); memcpy(&e[a], &e[b], sizeof(t)); memcpy(&e[b], &t, sizeof(t)); } static void updb(uint32_t db, unsigned int skip) { unsigned int i; for(i=0; i<256; i++) { if(i==skip) continue; if(pthread_mutex_lock(&cache[i].mutex)) { cli_errmsg("mutex lock fail\n"); continue; } cache[i].lastdb = db; pthread_mutex_unlock(&cache[i].mutex); } } static int cache_lookup_hash(unsigned char *md5, cli_ctx *ctx) { unsigned int i; int ret = CL_VIRUS; struct CACHE_ENTRY *e; struct CACHE *c; if(!cache) return ret; c = &cache[*md5]; e = c->items; if(pthread_mutex_lock(&c->mutex)) { cli_errmsg("mutex lock fail\n"); return ret; } if(c->lastdb <= ctx->engine->dbversion[0]) { if(c->lastdb < ctx->engine->dbversion[0]) { c->lastdb = ctx->engine->dbversion[0]; updb(c->lastdb, *md5); } else { for(i=0; i<cache_entries; i++) { if(!e[i].hits) break; if(e[i].dbver == c->lastdb && !memcmp(e[i].hash, md5 + 1, 15)) { e[i].hits++; cache_swap(e, i); ret = CL_CLEAN; cli_warnmsg("cached\n"); break; } } } } pthread_mutex_unlock(&c->mutex); return ret; } void cache_add(unsigned char *md5, cli_ctx *ctx) { unsigned int i, replace; struct CACHE_ENTRY *e; struct CACHE *c; if(!cache) return; c = &cache[*md5]; e = c->items; if(pthread_mutex_lock(&c->mutex)) { cli_errmsg("mutex lock fail\n"); return; } if(c->lastdb == ctx->engine->dbversion[0]) { replace = cache_entries; for(i=0; i<cache_entries; i++) { if(!e[i].hits) break; if(replace == cache_entries && e[i].dbver < c->lastdb) { replace = i; } else if(e[i].hits && !memcmp(e[i].hash, md5 + 1, 15)) { e[i].hits++; cache_swap(e, i); pthread_mutex_unlock(&c->mutex); return; } } if(replace == cache_entries) replace = cache_entries - 1 - (rand() % (cache_entries / CACHE_PERTURB)); e[replace].hits = 1; e[replace].dbver = c->lastdb; memcpy(e[replace].hash, md5 + 1, 15); cache_swap(e, replace); } pthread_mutex_unlock(&c->mutex); return; } int cache_check(unsigned char *hash, cli_ctx *ctx) { fmap_t *map = *ctx->fmap; size_t todo = map->len, at = 0;; cli_md5_ctx md5; if(!cache) return CL_VIRUS; cli_md5_init(&md5); while(todo) { void *buf; size_t readme = todo < FILEBUFF ? todo : FILEBUFF; if(!(buf = fmap_need_off_once(map, at, readme)) != readme) { lseek(desc, seekback, SEEK_SET); return CL_VIRUS; } todo -= readme; at += readme; cli_md5_update(&md5, buf, readme); } cli_md5_final(hash, &md5); return cache_lookup_hash(hash, ctx); }