From be825f57597b0e9dcf07d257e93f03e30935f7db Mon Sep 17 00:00:00 2001 From: Dirk Engling Date: Thu, 24 Nov 2022 04:20:06 +0100 Subject: Add support for dynamic accesslists --- ot_accesslist.c | 273 ++++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 236 insertions(+), 37 deletions(-) (limited to 'ot_accesslist.c') diff --git a/ot_accesslist.c b/ot_accesslist.c index a3a2049..078cebd 100644 --- a/ot_accesslist.c +++ b/ot_accesslist.c @@ -10,6 +10,11 @@ #include #include #include +#ifdef WANT_DYNAMIC_ACCESSLIST +#include +#include +#include +#endif /* Libowfat */ #include "byte.h" @@ -24,23 +29,80 @@ /* GLOBAL VARIABLES */ #ifdef WANT_ACCESSLIST - char *g_accesslist_filename; +char *g_accesslist_filename = NULL; +#ifdef WANT_DYNAMIC_ACCESSLIST +char *g_accesslist_pipe_add = NULL; +char *g_accesslist_pipe_delete = NULL; +#endif static pthread_mutex_t g_accesslist_mutex; -typedef struct { - ot_hash *list; - size_t size; -} ot_accesslist; -ot_accesslist * g_accesslist = NULL; -ot_accesslist * g_accesslist_old = NULL; +/* Accesslists are lock free linked lists. We can not make them locking, because every announce + would try to acquire the mutex, making it the most contested mutex in the whole of opentracker, + basically creating a central performance choke point. + + The idea is that updating the list heads happens under the g_accesslist_mutex guard and is + done atomically, while consumers might potentially still hold pointers deeper inside the list. + + Consumers (for now only via accesslist_hashisvalid) will always fetch the list head pointer + that is guaranteed to live for at least five minutes. This should be many orders of magnitudes + more than how long it will be needed by the bsearch done on the list. */ +struct ot_accesslist; +typedef struct ot_accesslist ot_accesslist; +struct ot_accesslist { + ot_hash *list; + size_t size; + ot_time base; + ot_accesslist *next; +}; +static ot_accesslist * g_accesslist = NULL; +#ifdef WANT_DYNAMIC_ACCESSLIST +static ot_accesslist * g_accesslist_add = NULL; +static ot_accesslist * g_accesslist_delete = NULL; +#endif +/* Helpers to work on access lists */ static int vector_compare_hash(const void *hash1, const void *hash2 ) { return memcmp( hash1, hash2, OT_HASH_COMPARE_SIZE ); } +static ot_accesslist * accesslist_free(ot_accesslist *accesslist) { + while (accesslist) { + ot_accesslist * this_accesslist = accesslist; + accesslist = this_accesslist->next; + free(this_accesslist->list); + free(this_accesslist); + } + return NULL; +} + +static ot_accesslist * accesslist_make(ot_accesslist *next, size_t size) { + ot_accesslist * accesslist_new = malloc(sizeof(ot_accesslist)); + if (accesslist_new) { + accesslist_new->list = size ? malloc(sizeof(ot_hash) * size) : NULL; + accesslist_new->size = size; + accesslist_new->base = g_now_minutes; + accesslist_new->next = next; + if (size && !accesslist_new->list) { + free(accesslist_new); + accesslist_new = NULL; + } + } + return accesslist_new; +} + +/* This must be called with g_accesslist_mutex held. + This will never delete head, because that might still be in use. */ +static void accesslist_clean(ot_accesslist *accesslist) { + while (accesslist && accesslist->next) { + if (accesslist->next->base + 5 < g_now_minutes) + accesslist->next = accesslist_free(accesslist->next); + accesslist = accesslist->next; + } +} + /* Read initial access list */ static void accesslist_readfile( void ) { - ot_accesslist * accesslist_new = malloc(sizeof(ot_accesslist)); + ot_accesslist * accesslist_new; ot_hash *info_hash; const char *map, *map_end, *read_offs; size_t maplen; @@ -54,14 +116,13 @@ static void accesslist_readfile( void ) { /* You need at least 41 bytes to pass an info_hash, make enough room for the maximum amount of them */ - accesslist_new->size = 0; - info_hash = accesslist_new->list = malloc( ( maplen / 41 ) * 20 ); - if( !accesslist_new->list ) { + accesslist_new = accesslist_make(g_accesslist, maplen / 41); + if( !accesslist_new ) { fprintf( stderr, "Warning: Not enough memory to allocate %zd bytes for accesslist buffer. May succeed later.\n", ( maplen / 41 ) * 20 ); mmap_unmap( map, maplen); - free(accesslist_new); return; } + info_hash = accesslist_new->list; /* No use to scan if there's not enough room for another full info_hash */ map_end = map + maplen - 40; @@ -71,18 +132,18 @@ static void accesslist_readfile( void ) { while( read_offs <= map_end ) { int i; for( i=0; i<(int)sizeof(ot_hash); ++i ) { - int eger1 = scan_fromhex( read_offs[ 2*i ] ); - int eger2 = scan_fromhex( read_offs[ 1 + 2*i ] ); + int eger1 = scan_fromhex( (unsigned char)read_offs[ 2*i ] ); + int eger2 = scan_fromhex( (unsigned char)read_offs[ 1 + 2*i ] ); if( eger1 < 0 || eger2 < 0 ) break; - (*info_hash)[i] = eger1 * 16 + eger2; + (*info_hash)[i] = (uint8_t)(eger1 * 16 + eger2); } if( i == sizeof(ot_hash) ) { read_offs += 40; /* Append accesslist to accesslist vector */ - if( read_offs == map_end || scan_fromhex( *read_offs ) < 0 ) + if( read_offs == map_end || scan_fromhex( (unsigned char)*read_offs ) < 0 ) ++info_hash; } @@ -100,14 +161,19 @@ static void accesslist_readfile( void ) { /* Now exchange the accesslist vector in the least race condition prone way */ pthread_mutex_lock(&g_accesslist_mutex); + accesslist_new->next = g_accesslist; + g_accesslist = accesslist_new; /* Only now set a new list */ + +#ifdef WANT_DYNAMIC_ACCESSLIST + /* If we have dynamic accesslists, reloading a new one will always void the add/delete lists. + Insert empty ones at the list head */ + if (g_accesslist_add && (accesslist_new = accesslist_make(g_accesslist_add, 0)) != NULL) + g_accesslist_add = accesslist_new; + if (g_accesslist_delete && (accesslist_new = accesslist_make(g_accesslist_delete, 0)) != NULL) + g_accesslist_delete = accesslist_new; +#endif - if (g_accesslist_old) { - free(g_accesslist_old->list); - free(g_accesslist_old); - } - - g_accesslist_old = g_accesslist; /* Keep a copy for later free */ - g_accesslist = accesslist_new; /* Only now set a new list */ + accesslist_clean(g_accesslist); pthread_mutex_unlock(&g_accesslist_mutex); } @@ -115,11 +181,25 @@ static void accesslist_readfile( void ) { int accesslist_hashisvalid( ot_hash hash ) { /* Get working copy of current access list */ ot_accesslist * accesslist = g_accesslist; - +#ifdef WANT_DYNAMIC_ACCESSLIST + ot_accesslist * accesslist_add, * accesslist_delete; +#endif void * exactmatch = NULL; if (accesslist) - exactmatch = bsearch( hash, accesslist->list, accesslist->size, OT_HASH_COMPARE_SIZE, vector_compare_hash ); + exactmatch = bsearch( hash, accesslist->list, accesslist->size, OT_HASH_COMPARE_SIZE, vector_compare_hash ); + +#ifdef WANT_DYNAMIC_ACCESSLIST + /* If we had no match on the main list, scan the list of dynamically added hashes */ + accesslist_add = g_accesslist_add; + if ((exactmatch == NULL) && accesslist_add) + exactmatch = bsearch( hash, accesslist_add->list, accesslist_add->size, OT_HASH_COMPARE_SIZE, vector_compare_hash ); + + /* If we found a matching hash on the main list, scan the list of dynamically deleted hashes */ + accesslist_delete = g_accesslist_delete; + if ((exactmatch != NULL) && accesslist_delete && bsearch( hash, accesslist_add->list, accesslist_add->size, OT_HASH_COMPARE_SIZE, vector_compare_hash )) + exactmatch = NULL; +#endif #ifdef WANT_ACCESSLIST_BLACK return exactmatch == NULL; @@ -138,6 +218,8 @@ static void * accesslist_worker( void * args ) { (void)args; while( 1 ) { + if (!g_opentracker_running) + return NULL; /* Initial attempt to read accesslist */ accesslist_readfile( ); @@ -148,27 +230,144 @@ static void * accesslist_worker( void * args ) { return NULL; } +#ifdef WANT_DYNAMIC_ACCESSLIST +static pthread_t thread_adder_id, thread_deleter_id; +static void * accesslist_adddel_worker(char * fifoname, ot_accesslist ** adding_to, ot_accesslist ** removing_from) { + struct stat st; + + if (!stat(fifoname, &st)) { + if (!S_ISFIFO(st.st_mode)) { + fprintf(stderr, "Error when starting dynamic accesslists: Found Non-FIFO file at %s.\nPlease remove it and restart opentracker.\n", fifoname); + return NULL; + } + } else { + int error = mkfifo(fifoname, 0755); + if (error && error != EEXIST) { + fprintf(stderr, "Error when starting dynamic accesslists: Couldn't create FIFO at %s, error: %s\n", fifoname, strerror(errno)); + return NULL; + } + } + + while (g_opentracker_running) { + FILE * fifo = fopen(fifoname, "r"); + char *line = NULL; + size_t linecap = 0; + ssize_t linelen; + + if (!fifo) { + fprintf(stderr, "Error when reading dynamic accesslists: Couldn't open FIFO at %s, error: %s\n", fifoname, strerror(errno)); + return NULL; + } + + while ((linelen = getline(&line, &linecap, fifo)) > 0) { + ot_hash info_hash; + int i; + + printf("Got line %*s", (int)linelen, line); + /* We do ignore anything that is not of the form "^[:xdigit:]{40}[^:xdigit:].*" + If there's not enough characters for an info_hash in the line, skip it. */ + if (linelen < 41) + continue; + + for( i=0; i<(int)sizeof(ot_hash); ++i ) { + int eger1 = scan_fromhex( (unsigned char)line[ 2*i ] ); + int eger2 = scan_fromhex( (unsigned char)line[ 1 + 2*i ] ); + if( eger1 < 0 || eger2 < 0 ) + break; + ((uint8_t*)info_hash)[i] = (uint8_t)(eger1 * 16 + eger2); + } +printf("parsed info_hash %20s\n", info_hash); + if( i != sizeof(ot_hash) ) + continue; + + /* From now on we modify g_accesslist_add and g_accesslist_delete, so prevent the + other worker threads from doing the same */ + pthread_mutex_lock(&g_accesslist_mutex); + + /* If the info hash is in the removing_from list, create a new head without that entry */ + if (*removing_from && (*removing_from)->list) { + ot_hash * exactmatch = bsearch( info_hash, (*removing_from)->list, (*removing_from)->size, OT_HASH_COMPARE_SIZE, vector_compare_hash ); + if (exactmatch) { + ptrdiff_t off = exactmatch - (*removing_from)->list; + ot_accesslist * accesslist_new = accesslist_make(*removing_from, (*removing_from)->size - 1); + if (accesslist_new) { + memcpy(accesslist_new->list, (*removing_from)->list, sizeof(ot_hash) * off); + memcpy(accesslist_new->list + off, (*removing_from)->list + off + 1, (*removing_from)->size - off - 1); + *removing_from = accesslist_new; + } + } + } + accesslist_clean(*removing_from); + + /* Simple case: there's no adding_to list yet, create one with one member */ + if (!*adding_to) { + *adding_to = accesslist_make(NULL, 1); + if (*adding_to) + memcpy((*adding_to)->list, info_hash, sizeof(ot_hash)); + } else { + int exactmatch = 0; + ot_hash * insert_point = binary_search( info_hash, (*adding_to)->list, (*adding_to)->size, OT_HASH_COMPARE_SIZE, sizeof(ot_hash), &exactmatch ); + + /* Only if the info hash is not in the adding_to list, create a new head with that entry */ + if (!exactmatch) { + ot_accesslist * accesslist_new = accesslist_make(*adding_to, (*adding_to)->size + 1); + ptrdiff_t off = insert_point - (*adding_to)->list; + if (accesslist_new) { + memcpy(accesslist_new->list, (*adding_to)->list, sizeof(ot_hash) * off); + memcpy(accesslist_new->list + off, info_hash, sizeof(info_hash)); + memcpy(accesslist_new->list + off + 1, (*adding_to)->list + off, (*adding_to)->size - off); + *adding_to = accesslist_new; + } + } + } + accesslist_clean(*adding_to); + + pthread_mutex_unlock(&g_accesslist_mutex); + } + + fclose(fifo); + } + return NULL; +} + +static void * accesslist_adder_worker( void * args ) { + (void)args; + return accesslist_adddel_worker(g_accesslist_pipe_add, &g_accesslist_add, &g_accesslist_delete); +} +static void * accesslist_deleter_worker( void * args ) { + (void)args; + return accesslist_adddel_worker(g_accesslist_pipe_delete, &g_accesslist_delete, &g_accesslist_add); +} +#endif + static pthread_t thread_id; void accesslist_init( ) { pthread_mutex_init(&g_accesslist_mutex, NULL); pthread_create( &thread_id, NULL, accesslist_worker, NULL ); +#ifdef WANT_DYNAMIC_ACCESSLIST + if (g_accesslist_pipe_add) + pthread_create( &thread_adder_id, NULL, accesslist_adder_worker, NULL ); + if (g_accesslist_pipe_delete) + pthread_create( &thread_deleter_id, NULL, accesslist_deleter_worker, NULL ); +#endif } void accesslist_deinit( void ) { - pthread_cancel( thread_id ); - pthread_mutex_destroy(&g_accesslist_mutex); + /* Wake up sleeping worker */ + pthread_kill(thread_id, SIGHUP); - if (g_accesslist_old) { - free(g_accesslist_old->list); - free(g_accesslist_old); - g_accesslist_old = 0; - } + pthread_mutex_lock(&g_accesslist_mutex); - if (g_accesslist) { - free(g_accesslist->list); - free(g_accesslist); - g_accesslist = 0; - } + g_accesslist = accesslist_free(g_accesslist); + +#ifdef WANT_DYNAMIC_ACCESSLIST + g_accesslist_add = accesslist_free(g_accesslist_add); + g_accesslist_delete = accesslist_free(g_accesslist_delete); +#endif + + pthread_mutex_unlock(&g_accesslist_mutex); + pthread_cancel( thread_id ); + pthread_mutex_destroy(&g_accesslist_mutex); } #endif -- cgit v1.2.3