mirror of git://git.gnupg.org/gnupg.git
agent: Introduce management of timer to expire cache entries.
* agent/cache.c (struct timer_s): New. (struct cache_item_s): Add a member filed T for timer. (the_timer_list, the_timer_list_new): New. (insert_to_timer_list_new, insert_to_timer_list): New. (remove_from_timer_list, remove_from_timer_list_new): New. (housekeeping): Remove. (compute_expiration, update_expiration): New. (do_expire): New. (TIMERTICK_INTERVAL): Remove. (agent_cache_expiration): Use timer list to manage the expiration of cache entries. (agent_flush_cache): Call update_expiration when needed. (agent_put_cache): Don't call housekeeping any more, but update_expiration for an entry in question. (agent_get_cache): Likewise. -- GnuPG-bug-id: 6681 Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka
parent
76a2f18028
commit
92de0387f0
382
agent/cache.c
382
agent/cache.c
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@ -53,8 +53,20 @@ struct secret_data_s {
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char data[1]; /* A string. */
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};
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/* The cache object. */
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/* The type of cache object. */
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typedef struct cache_item_s *ITEM;
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/* The timer entry in a linked list. */
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struct timer_s {
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ITEM next;
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int tv_sec;
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int reason;
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};
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#define CACHE_EXPIRE_UNUSED 0
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#define CACHE_EXPIRE_LAST_ACCESS 1
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#define CACHE_EXPIRE_CREATION 2
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/* The cache object. */
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struct cache_item_s {
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ITEM next;
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time_t created;
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@ -63,12 +75,18 @@ struct cache_item_s {
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struct secret_data_s *pw;
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cache_mode_t cache_mode;
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int restricted; /* The value of ctrl->restricted is part of the key. */
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struct timer_s t;
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char key[1];
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};
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/* The cache himself. */
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static ITEM thecache;
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/* The timer list of expiration, in active. */
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static ITEM the_timer_list;
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/* Newly created entries, to be inserted into the timer list. */
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static ITEM the_timer_list_new;
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/* NULL or the last cache key stored by agent_store_cache_hit. */
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static char *last_stored_cache_key;
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@ -193,123 +211,301 @@ new_data (const char *string, struct secret_data_s **r_data)
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}
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/* Check whether there are items to expire. */
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static void
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housekeeping (void)
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insert_to_timer_list_new (ITEM entry)
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{
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ITEM r, rprev;
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entry->t.next = the_timer_list_new;
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the_timer_list_new = entry;
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}
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/* Insert to the active timer list. */
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static void
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insert_to_timer_list (struct timespec *ts, ITEM entry)
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{
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ITEM e, eprev;
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if (!the_timer_list || ts->tv_sec >= entry->t.tv_sec)
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{
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if (the_timer_list && ts->tv_nsec)
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the_timer_list->t.tv_sec++;
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ts->tv_sec = entry->t.tv_sec;
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ts->tv_nsec = 0;
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entry->t.tv_sec = 0;
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entry->t.next = the_timer_list;
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the_timer_list = entry;
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return;
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}
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entry->t.tv_sec -= ts->tv_sec;
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eprev = NULL;
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for (e = the_timer_list; e; e = e->t.next)
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{
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if (e->t.tv_sec > entry->t.tv_sec)
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break;
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eprev = e;
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entry->t.tv_sec -= e->t.tv_sec;
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}
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entry->t.next = e;
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if (e)
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e->t.tv_sec -= entry->t.tv_sec;
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if (eprev)
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eprev->t.next = entry;
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else
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the_timer_list = entry;
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}
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static void
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remove_from_timer_list (ITEM entry)
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{
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ITEM e, eprev;
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eprev = NULL;
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for (e = the_timer_list; e; e = e->t.next)
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if (e != entry)
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eprev = e;
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else
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{
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if (e->t.next)
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e->t.next->t.tv_sec += e->t.tv_sec;
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if (eprev)
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eprev->t.next = e->t.next;
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else
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the_timer_list = e->t.next;
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break;
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}
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entry->t.next = NULL;
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entry->t.tv_sec = 0;
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}
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static void
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remove_from_timer_list_new (ITEM entry)
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{
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ITEM e, eprev;
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eprev = NULL;
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for (e = the_timer_list_new; e; e = e->t.next)
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if (e != entry)
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eprev = e;
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else
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{
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if (e->t.next)
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e->t.next->t.tv_sec += e->t.tv_sec;
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if (eprev)
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eprev->t.next = e->t.next;
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else
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the_timer_list_new = e->t.next;
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break;
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}
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entry->t.next = NULL;
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entry->t.tv_sec = 0;
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}
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static int
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compute_expiration (ITEM r)
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{
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unsigned long maxttl;
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time_t current = gnupg_get_time ();
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time_t next;
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/* First expire the actual data */
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for (r=thecache; r; r = r->next)
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if (r->cache_mode == CACHE_MODE_PIN)
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return 0; /* Don't let it expire - scdaemon explicitly flushes them. */
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if (!r->pw)
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{
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if (r->cache_mode == CACHE_MODE_PIN)
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; /* Don't let it expire - scdaemon explicitly flushes them. */
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else if (r->pw && r->ttl >= 0 && r->accessed + r->ttl < current)
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{
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if (DBG_CACHE)
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log_debug (" expired '%s'.%d (%ds after last access)\n",
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r->key, r->restricted, r->ttl);
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release_data (r->pw);
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r->pw = NULL;
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r->accessed = current;
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}
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/* Expire an old and unused entry after 30 minutes. */
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r->t.tv_sec = 60*30;
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r->t.reason = CACHE_EXPIRE_UNUSED;
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return 1;
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}
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/* Second, make sure that we also remove them based on the created
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* stamp so that the user has to enter it from time to time. We
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* don't do this for data items which are used to storage secrets in
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* meory and are not user entered passphrases etc. */
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for (r=thecache; r; r = r->next)
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switch (r->cache_mode)
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{
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unsigned long maxttl;
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switch (r->cache_mode)
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{
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case CACHE_MODE_DATA:
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case CACHE_MODE_PIN:
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continue; /* No MAX TTL here. */
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case CACHE_MODE_SSH: maxttl = opt.max_cache_ttl_ssh; break;
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default: maxttl = opt.max_cache_ttl; break;
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}
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if (r->pw && r->created + maxttl < current)
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{
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if (DBG_CACHE)
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log_debug (" expired '%s'.%d (%lus after creation)\n",
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r->key, r->restricted, opt.max_cache_ttl);
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release_data (r->pw);
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r->pw = NULL;
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r->accessed = current;
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}
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case CACHE_MODE_DATA:
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case CACHE_MODE_PIN:
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maxttl = 0; /* No MAX TTL here. */
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break;
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case CACHE_MODE_SSH: maxttl = opt.max_cache_ttl_ssh; break;
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default: maxttl = opt.max_cache_ttl; break;
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}
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/* Third, make sure that we don't have too many items in the list.
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* Expire old and unused entries after 30 minutes. */
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for (rprev=NULL, r=thecache; r; )
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if (maxttl)
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{
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if (!r->pw && r->ttl >= 0 && r->accessed + 60*30 < current)
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if (r->created + maxttl < current)
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{
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ITEM r2 = r->next;
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if (DBG_CACHE)
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log_debug (" removed '%s'.%d (mode %d) (slot not used for 30m)\n",
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r->key, r->restricted, r->cache_mode);
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xfree (r);
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if (!rprev)
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thecache = r2;
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else
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rprev->next = r2;
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r = r2;
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}
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else
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{
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rprev = r;
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r = r->next;
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r->t.tv_sec = 0;
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r->t.reason = CACHE_EXPIRE_CREATION;
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return 1;
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}
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next = r->created + maxttl - current;
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}
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else
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next = 0;
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if (r->ttl >= 0 && (next == 0 || r->ttl < next))
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{
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r->t.tv_sec = r->ttl;
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r->t.reason = CACHE_EXPIRE_LAST_ACCESS;
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return 1;
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}
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if (next)
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{
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r->t.tv_sec = next;
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r->t.reason = CACHE_EXPIRE_CREATION;
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return 1;
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}
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return 0;
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}
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static void
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update_expiration (ITEM entry, int is_new_entry)
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{
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if (!is_new_entry)
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{
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remove_from_timer_list (entry);
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remove_from_timer_list_new (entry);
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}
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if (compute_expiration (entry))
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{
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insert_to_timer_list_new (entry);
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agent_kick_the_loop ();
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}
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}
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#define TIMERTICK_INTERVAL (4)
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/* Expire the cache entry. Returns 1 when the entry should be removed
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* from the cache. */
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static int
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do_expire (ITEM e)
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{
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if (!e->pw)
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/* Unused entry after 30 minutes. */
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return 1;
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if (e->t.reason == CACHE_EXPIRE_LAST_ACCESS)
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{
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if (DBG_CACHE)
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log_debug (" expired '%s'.%d (%ds after last access)\n",
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e->key, e->restricted, e->ttl);
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}
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else
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{
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if (DBG_CACHE)
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log_debug (" expired '%s'.%d (%lus after creation)\n",
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e->key, e->restricted, opt.max_cache_ttl);
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}
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release_data (e->pw);
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e->pw = NULL;
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e->accessed = 0;
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if (compute_expiration (e))
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insert_to_timer_list_new (e);
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return 0;
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}
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struct timespec *
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agent_cache_expiration (void)
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{
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static struct timespec abstime;
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static struct timespec timeout;
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static int initialized = 0;
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struct timespec *tp;
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struct timespec curtime;
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int res;
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int expired = 0;
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ITEM e, enext;
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if (!initialized)
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{
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initialized = 1;
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npth_clock_gettime (&abstime);
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abstime.tv_sec += TIMERTICK_INTERVAL;
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}
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res = npth_mutex_lock (&cache_lock);
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if (res)
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log_fatal ("failed to acquire cache mutex: %s\n", strerror (res));
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npth_clock_gettime (&curtime);
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if (!(npth_timercmp (&curtime, &abstime, <)))
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if (the_timer_list)
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{
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/* Timeout. */
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npth_clock_gettime (&abstime);
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abstime.tv_sec += TIMERTICK_INTERVAL;
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if (DBG_CACHE)
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log_debug ("agent_cache_housekeeping\n");
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res = npth_mutex_lock (&cache_lock);
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if (res)
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log_fatal ("failed to acquire cache mutex: %s\n", strerror (res));
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housekeeping ();
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res = npth_mutex_unlock (&cache_lock);
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if (res)
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log_fatal ("failed to release cache mutex: %s\n", strerror (res));
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if (npth_timercmp (&abstime, &curtime, <))
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expired = 1;
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else
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npth_timersub (&abstime, &curtime, &timeout);
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}
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npth_timersub (&abstime, &curtime, &timeout);
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return &timeout;
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if (expired && (e = the_timer_list) && e->t.tv_sec == 0)
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{
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the_timer_list = e->t.next;
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e->t.next = NULL;
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if (do_expire (e))
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{
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ITEM r, rprev;
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if (DBG_CACHE)
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log_debug (" removed '%s'.%d (mode %d) (slot not used for 30m)\n",
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e->key, e->restricted, e->cache_mode);
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rprev = NULL;
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for (r = thecache; r; r = r->next)
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if (r == e)
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{
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if (!rprev)
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thecache = r->next;
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else
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rprev->next = r->next;
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break;
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}
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else
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rprev = r;
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remove_from_timer_list_new (e);
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xfree (e);
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}
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}
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if (expired || !the_timer_list)
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timeout.tv_sec = timeout.tv_nsec = 0;
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for (e = the_timer_list_new; e; e = enext)
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{
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enext = e->t.next;
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e->t.next = NULL;
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insert_to_timer_list (&timeout, e);
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}
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the_timer_list_new = NULL;
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if (!the_timer_list)
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tp = NULL;
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else
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{
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if (the_timer_list->t.tv_sec != 0)
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{
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timeout.tv_sec += the_timer_list->t.tv_sec;
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the_timer_list->t.tv_sec = 0;
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}
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npth_timeradd (&timeout, &curtime, &abstime);
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tp = &timeout;
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}
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res = npth_mutex_unlock (&cache_lock);
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if (res)
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log_fatal ("failed to release cache mutex: %s\n", strerror (res));
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return tp;
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}
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@ -337,6 +533,7 @@ agent_flush_cache (int pincache_only)
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release_data (r->pw);
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r->pw = NULL;
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r->accessed = 0;
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update_expiration (r, 0);
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}
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}
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@ -381,7 +578,6 @@ agent_put_cache (ctrl_t ctrl, const char *key, cache_mode_t cache_mode,
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if (DBG_CACHE)
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log_debug ("agent_put_cache '%s'.%d (mode %d) requested ttl=%d\n",
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key, restricted, cache_mode, ttl);
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housekeeping ();
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if (!ttl)
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{
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@ -433,6 +629,7 @@ agent_put_cache (ctrl_t ctrl, const char *key, cache_mode_t cache_mode,
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err = new_data (data, &r->pw);
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if (err)
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log_error ("error replacing cache item: %s\n", gpg_strerror (err));
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update_expiration (r, 0);
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}
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}
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else if (data) /* Insert. */
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@ -454,6 +651,7 @@ agent_put_cache (ctrl_t ctrl, const char *key, cache_mode_t cache_mode,
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{
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r->next = thecache;
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thecache = r;
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update_expiration (r, 1);
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}
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}
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if (err)
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@ -501,7 +699,6 @@ agent_get_cache (ctrl_t ctrl, const char *key, cache_mode_t cache_mode)
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log_debug ("agent_get_cache '%s'.%d (mode %d)%s ...\n",
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key, restricted, cache_mode,
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last_stored? " (stored cache key)":"");
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housekeeping ();
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for (r=thecache; r; r = r->next)
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{
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@ -523,7 +720,10 @@ agent_get_cache (ctrl_t ctrl, const char *key, cache_mode_t cache_mode)
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* below. Note also that we don't update the accessed time
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* for data items. */
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if (r->cache_mode != CACHE_MODE_DATA)
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r->accessed = gnupg_get_time ();
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{
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r->accessed = gnupg_get_time ();
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update_expiration (r, 0);
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}
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if (DBG_CACHE)
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log_debug ("... hit\n");
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if (r->pw->totallen < 32)
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