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-rw-r--r--main/astobj2.c771
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diff --git a/main/astobj2.c b/main/astobj2.c
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-/*
- * astobj2 - replacement containers for asterisk data structures.
- *
- * Copyright (C) 2006 Marta Carbone, Luigi Rizzo - Univ. di Pisa, Italy
- *
- * See http://www.asterisk.org for more information about
- * the Asterisk project. Please do not directly contact
- * any of the maintainers of this project for assistance;
- * the project provides a web site, mailing lists and IRC
- * channels for your use.
- *
- * This program is free software, distributed under the terms of
- * the GNU General Public License Version 2. See the LICENSE file
- * at the top of the source tree.
- */
-
-/*
- * Function implementing astobj2 objects.
- */
-#include "asterisk.h"
-
-ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
-
-#include "asterisk/astobj2.h"
-#include "asterisk/utils.h"
-#include "asterisk/cli.h"
-
-/*!
- * astobj2 objects are always prepended this data structure,
- * which contains a lock, a reference counter,
- * the flags and a pointer to a destructor.
- * The refcount is used to decide when it is time to
- * invoke the destructor.
- * The magic number is used for consistency check.
- * XXX the lock is not always needed, and its initialization may be
- * expensive. Consider making it external.
- */
-struct __priv_data {
- ast_mutex_t lock;
- int ref_counter;
- ao2_destructor_fn destructor_fn;
- /*! for stats */
- size_t data_size;
- /*! magic number. This is used to verify that a pointer passed in is a
- * valid astobj2 */
- uint32_t magic;
-};
-
-#define AO2_MAGIC 0xa570b123
-
-/*!
- * What an astobj2 object looks like: fixed-size private data
- * followed by variable-size user data.
- */
-struct astobj2 {
- struct __priv_data priv_data;
- void *user_data[0];
-};
-
-#ifdef AST_DEVMODE
-#define AO2_DEBUG 1
-#endif
-
-#ifdef AO2_DEBUG
-struct ao2_stats {
- volatile int total_objects;
- volatile int total_mem;
- volatile int total_containers;
- volatile int total_refs;
- volatile int total_locked;
-};
-
-static struct ao2_stats ao2;
-#endif
-
-#ifndef HAVE_BKTR /* backtrace support */
-void ao2_bt(void) {}
-#else
-#include <execinfo.h> /* for backtrace */
-
-void ao2_bt(void)
-{
- int c, i;
-#define N1 20
- void *addresses[N1];
- char **strings;
-
- c = backtrace(addresses, N1);
- strings = backtrace_symbols(addresses,c);
- ast_verbose("backtrace returned: %d\n", c);
- for(i = 0; i < c; i++) {
- ast_verbose("%d: %p %s\n", i, addresses[i], strings[i]);
- }
- free(strings);
-}
-#endif
-
-/*!
- * \brief convert from a pointer _p to a user-defined object
- *
- * \return the pointer to the astobj2 structure
- */
-static inline struct astobj2 *INTERNAL_OBJ(void *user_data)
-{
- struct astobj2 *p;
-
- if (!user_data) {
- ast_log(LOG_ERROR, "user_data is NULL\n");
- return NULL;
- }
-
- p = (struct astobj2 *) ((char *) user_data - sizeof(*p));
- if (AO2_MAGIC != (p->priv_data.magic) ) {
- ast_log(LOG_ERROR, "bad magic number 0x%x for %p\n", p->priv_data.magic, p);
- p = NULL;
- }
-
- return p;
-}
-
-/*!
- * \brief convert from a pointer _p to an astobj2 object
- *
- * \return the pointer to the user-defined portion.
- */
-#define EXTERNAL_OBJ(_p) ((_p) == NULL ? NULL : (_p)->user_data)
-
-#ifndef DEBUG_THREADS
-int ao2_lock(void *user_data)
-#else
-int _ao2_lock(void *user_data, const char *file, const char *func, int line, const char *var)
-#endif
-{
- struct astobj2 *p = INTERNAL_OBJ(user_data);
-
- if (p == NULL)
- return -1;
-
-#ifdef AO2_DEBUG
- ast_atomic_fetchadd_int(&ao2.total_locked, 1);
-#endif
-
-#ifndef DEBUG_THREADS
- return ast_mutex_lock(&p->priv_data.lock);
-#else
- return __ast_pthread_mutex_lock(file, line, func, var, &p->priv_data.lock);
-#endif
-}
-
-#ifndef DEBUG_THREADS
-int ao2_trylock(void *user_data)
-#else
-int _ao2_trylock(void *user_data, const char *file, const char *func, int line, const char *var)
-#endif
-{
- struct astobj2 *p = INTERNAL_OBJ(user_data);
- int res;
-
- if (p == NULL)
- return -1;
-
-#ifndef DEBUG_THREADS
- res = ast_mutex_trylock(&p->priv_data.lock);
-#else
- res = __ast_pthread_mutex_trylock(file, line, func, var, &p->priv_data.lock);
-#endif
-
-#ifdef AO2_DEBUG
- if (!res) {
- ast_atomic_fetchadd_int(&ao2.total_locked, 1);
- }
-#endif
-
- return res;
-}
-
-#ifndef DEBUG_THREADS
-int ao2_unlock(void *user_data)
-#else
-int _ao2_unlock(void *user_data, const char *file, const char *func, int line, const char *var)
-#endif
-{
- struct astobj2 *p = INTERNAL_OBJ(user_data);
-
- if (p == NULL)
- return -1;
-
-#ifdef AO2_DEBUG
- ast_atomic_fetchadd_int(&ao2.total_locked, -1);
-#endif
-
-#ifndef DEBUG_THREADS
- return ast_mutex_unlock(&p->priv_data.lock);
-#else
- return __ast_pthread_mutex_unlock(file, line, func, var, &p->priv_data.lock);
-#endif
-}
-
-/*
- * The argument is a pointer to the user portion.
- */
-int ao2_ref(void *user_data, const int delta)
-{
- int current_value;
- int ret;
- struct astobj2 *obj = INTERNAL_OBJ(user_data);
-
- if (obj == NULL)
- return -1;
-
- /* if delta is 0, just return the refcount */
- if (delta == 0)
- return (obj->priv_data.ref_counter);
-
- /* we modify with an atomic operation the reference counter */
- ret = ast_atomic_fetchadd_int(&obj->priv_data.ref_counter, delta);
- current_value = ret + delta;
-
-#ifdef AO2_DEBUG
- ast_atomic_fetchadd_int(&ao2.total_refs, delta);
-#endif
-
- /* this case must never happen */
- if (current_value < 0)
- ast_log(LOG_ERROR, "refcount %d on object %p\n", current_value, user_data);
-
- if (current_value <= 0) { /* last reference, destroy the object */
- if (obj->priv_data.destructor_fn != NULL)
- obj->priv_data.destructor_fn(user_data);
-
- ast_mutex_destroy(&obj->priv_data.lock);
-#ifdef AO2_DEBUG
- ast_atomic_fetchadd_int(&ao2.total_mem, - obj->priv_data.data_size);
- ast_atomic_fetchadd_int(&ao2.total_objects, -1);
-#endif
- /* for safety, zero-out the astobj2 header and also the
- * first word of the user-data, which we make sure is always
- * allocated. */
- bzero(obj, sizeof(struct astobj2 *) + sizeof(void *) );
- free(obj);
- }
-
- return ret;
-}
-
-/*
- * We always alloc at least the size of a void *,
- * for debugging purposes.
- */
-void *ao2_alloc(size_t data_size, ao2_destructor_fn destructor_fn)
-{
- /* allocation */
- struct astobj2 *obj;
-
- if (data_size < sizeof(void *))
- data_size = sizeof(void *);
-
- obj = ast_calloc(1, sizeof(*obj) + data_size);
-
- if (obj == NULL)
- return NULL;
-
- ast_mutex_init(&obj->priv_data.lock);
- obj->priv_data.magic = AO2_MAGIC;
- obj->priv_data.data_size = data_size;
- obj->priv_data.ref_counter = 1;
- obj->priv_data.destructor_fn = destructor_fn; /* can be NULL */
-
-#ifdef AO2_DEBUG
- ast_atomic_fetchadd_int(&ao2.total_objects, 1);
- ast_atomic_fetchadd_int(&ao2.total_mem, data_size);
- ast_atomic_fetchadd_int(&ao2.total_refs, 1);
-#endif
-
- /* return a pointer to the user data */
- return EXTERNAL_OBJ(obj);
-}
-
-/* internal callback to destroy a container. */
-static void container_destruct(void *c);
-
-/* each bucket in the container is a tailq. */
-AST_LIST_HEAD_NOLOCK(bucket, bucket_list);
-
-/*!
- * A container; stores the hash and callback functions, information on
- * the size, the hash bucket heads, and a version number, starting at 0
- * (for a newly created, empty container)
- * and incremented every time an object is inserted or deleted.
- * The assumption is that an object is never moved in a container,
- * but removed and readded with the new number.
- * The version number is especially useful when implementing iterators.
- * In fact, we can associate a unique, monotonically increasing number to
- * each object, which means that, within an iterator, we can store the
- * version number of the current object, and easily look for the next one,
- * which is the next one in the list with a higher number.
- * Since all objects have a version >0, we can use 0 as a marker for
- * 'we need the first object in the bucket'.
- *
- * \todo Linking and unlink objects is typically expensive, as it
- * involves a malloc() of a small object which is very inefficient.
- * To optimize this, we allocate larger arrays of bucket_list's
- * when we run out of them, and then manage our own freelist.
- * This will be more efficient as we can do the freelist management while
- * we hold the lock (that we need anyways).
- */
-struct ao2_container {
- ao2_hash_fn hash_fn;
- ao2_callback_fn cmp_fn;
- int n_buckets;
- /*! Number of elements in the container */
- int elements;
- /*! described above */
- int version;
- /*! variable size */
- struct bucket buckets[0];
-};
-
-/*!
- * \brief always zero hash function
- *
- * it is convenient to have a hash function that always returns 0.
- * This is basically used when we want to have a container that is
- * a simple linked list.
- *
- * \returns 0
- */
-static int hash_zero(const void *user_obj, const int flags)
-{
- return 0;
-}
-
-/*
- * A container is just an object, after all!
- */
-struct ao2_container *
-ao2_container_alloc(const unsigned int n_buckets, ao2_hash_fn hash_fn,
- ao2_callback_fn cmp_fn)
-{
- /* XXX maybe consistency check on arguments ? */
- /* compute the container size */
- size_t container_size = sizeof(struct ao2_container) + n_buckets * sizeof(struct bucket);
-
- struct ao2_container *c = ao2_alloc(container_size, container_destruct);
-
- if (!c)
- return NULL;
-
- c->version = 1; /* 0 is a reserved value here */
- c->n_buckets = n_buckets;
- c->hash_fn = hash_fn ? hash_fn : hash_zero;
- c->cmp_fn = cmp_fn;
-
-#ifdef AO2_DEBUG
- ast_atomic_fetchadd_int(&ao2.total_containers, 1);
-#endif
-
- return c;
-}
-
-/*!
- * return the number of elements in the container
- */
-int ao2_container_count(struct ao2_container *c)
-{
- return c->elements;
-}
-
-/*!
- * A structure to create a linked list of entries,
- * used within a bucket.
- * XXX \todo this should be private to the container code
- */
-struct bucket_list {
- AST_LIST_ENTRY(bucket_list) entry;
- int version;
- struct astobj2 *astobj; /* pointer to internal data */
-};
-
-/*
- * link an object to a container
- */
-void *__ao2_link(struct ao2_container *c, void *user_data, int iax2_hack)
-{
- int i;
- /* create a new list entry */
- struct bucket_list *p;
- struct astobj2 *obj = INTERNAL_OBJ(user_data);
-
- if (!obj)
- return NULL;
-
- if (INTERNAL_OBJ(c) == NULL)
- return NULL;
-
- p = ast_calloc(1, sizeof(*p));
- if (!p)
- return NULL;
-
- i = c->hash_fn(user_data, OBJ_POINTER);
-
- ao2_lock(c);
- i %= c->n_buckets;
- p->astobj = obj;
- p->version = ast_atomic_fetchadd_int(&c->version, 1);
- if (iax2_hack)
- AST_LIST_INSERT_HEAD(&c->buckets[i], p, entry);
- else
- AST_LIST_INSERT_TAIL(&c->buckets[i], p, entry);
- ast_atomic_fetchadd_int(&c->elements, 1);
- ao2_ref(user_data, +1);
- ao2_unlock(c);
-
- return p;
-}
-
-/*!
- * \brief another convenience function is a callback that matches on address
- */
-int ao2_match_by_addr(void *user_data, void *arg, int flags)
-{
- return (user_data == arg) ? (CMP_MATCH | CMP_STOP) : 0;
-}
-
-/*
- * Unlink an object from the container
- * and destroy the associated * ao2_bucket_list structure.
- */
-void *ao2_unlink(struct ao2_container *c, void *user_data)
-{
- if (INTERNAL_OBJ(user_data) == NULL) /* safety check on the argument */
- return NULL;
-
- ao2_callback(c, OBJ_UNLINK | OBJ_POINTER | OBJ_NODATA, ao2_match_by_addr, user_data);
-
- return NULL;
-}
-
-/*!
- * \brief special callback that matches all
- */
-static int cb_true(void *user_data, void *arg, int flags)
-{
- return CMP_MATCH;
-}
-
-/*!
- * Browse the container using different stategies accoding the flags.
- * \return Is a pointer to an object or to a list of object if OBJ_MULTIPLE is
- * specified.
- */
-void *ao2_callback(struct ao2_container *c,
- const enum search_flags flags,
- ao2_callback_fn cb_fn, void *arg)
-{
- int i, last; /* search boundaries */
- void *ret = NULL;
-
- if (INTERNAL_OBJ(c) == NULL) /* safety check on the argument */
- return NULL;
-
- if ((flags & (OBJ_MULTIPLE | OBJ_NODATA)) == OBJ_MULTIPLE) {
- ast_log(LOG_WARNING, "multiple data return not implemented yet (flags %x)\n", flags);
- return NULL;
- }
-
- /* override the match function if necessary */
-#if 0
- /* Removing this slightly changes the meaning of OBJ_POINTER, but makes it
- * do what I want it to. I'd like to hint to ao2_callback that the arg is
- * of the same object type, so it can be passed to the hash function.
- * However, I don't want to imply that this is the object being searched for. */
- if (flags & OBJ_POINTER)
- cb_fn = match_by_addr;
- else
-#endif
- if (cb_fn == NULL) /* if NULL, match everything */
- cb_fn = cb_true;
- /*
- * XXX this can be optimized.
- * If we have a hash function and lookup by pointer,
- * run the hash function. Otherwise, scan the whole container
- * (this only for the time being. We need to optimize this.)
- */
- if ((flags & OBJ_POINTER)) /* we know hash can handle this case */
- i = c->hash_fn(arg, flags & OBJ_POINTER) % c->n_buckets;
- else /* don't know, let's scan all buckets */
- i = -1; /* XXX this must be fixed later. */
-
- /* determine the search boundaries: i..last-1 */
- if (i < 0) {
- i = 0;
- last = c->n_buckets;
- } else {
- last = i + 1;
- }
-
- ao2_lock(c); /* avoid modifications to the content */
-
- for (; i < last ; i++) {
- /* scan the list with prev-cur pointers */
- struct bucket_list *cur;
-
- AST_LIST_TRAVERSE_SAFE_BEGIN(&c->buckets[i], cur, entry) {
- int match = cb_fn(EXTERNAL_OBJ(cur->astobj), arg, flags) & (CMP_MATCH | CMP_STOP);
-
- /* we found the object, performing operations according flags */
- if (match == 0) { /* no match, no stop, continue */
- continue;
- } else if (match == CMP_STOP) { /* no match but stop, we are done */
- i = last;
- break;
- }
- /* we have a match (CMP_MATCH) here */
- if (!(flags & OBJ_NODATA)) { /* if must return the object, record the value */
- /* it is important to handle this case before the unlink */
- ret = EXTERNAL_OBJ(cur->astobj);
- ao2_ref(ret, 1);
- }
-
- if (flags & OBJ_UNLINK) { /* must unlink */
- struct bucket_list *x = cur;
-
- /* we are going to modify the container, so update version */
- ast_atomic_fetchadd_int(&c->version, 1);
- AST_LIST_REMOVE_CURRENT(&c->buckets[i], entry);
- /* update number of elements and version */
- ast_atomic_fetchadd_int(&c->elements, -1);
- ao2_ref(EXTERNAL_OBJ(x->astobj), -1);
- free(x); /* free the link record */
- }
-
- if ((match & CMP_STOP) || (flags & OBJ_MULTIPLE) == 0) {
- /* We found the only match we need */
- i = last; /* force exit from outer loop */
- break;
- }
- if (!(flags & OBJ_NODATA)) {
-#if 0 /* XXX to be completed */
- /*
- * This is the multiple-return case. We need to link
- * the object in a list. The refcount is already increased.
- */
-#endif
- }
- }
- AST_LIST_TRAVERSE_SAFE_END
- }
- ao2_unlock(c);
- return ret;
-}
-
-/*!
- * the find function just invokes the default callback with some reasonable flags.
- */
-void *ao2_find(struct ao2_container *c, void *arg, enum search_flags flags)
-{
- return ao2_callback(c, flags, c->cmp_fn, arg);
-}
-
-/*!
- * initialize an iterator so we start from the first object
- */
-struct ao2_iterator ao2_iterator_init(struct ao2_container *c, int flags)
-{
- struct ao2_iterator a = {
- .c = c,
- .flags = flags
- };
-
- return a;
-}
-
-/*
- * move to the next element in the container.
- */
-void * ao2_iterator_next(struct ao2_iterator *a)
-{
- int lim;
- struct bucket_list *p = NULL;
- void *ret = NULL;
-
- if (INTERNAL_OBJ(a->c) == NULL)
- return NULL;
-
- if (!(a->flags & F_AO2I_DONTLOCK))
- ao2_lock(a->c);
-
- /* optimization. If the container is unchanged and
- * we have a pointer, try follow it
- */
- if (a->c->version == a->c_version && (p = a->obj) ) {
- if ( (p = AST_LIST_NEXT(p, entry)) )
- goto found;
- /* nope, start from the next bucket */
- a->bucket++;
- a->version = 0;
- a->obj = NULL;
- }
-
- lim = a->c->n_buckets;
-
- /* Browse the buckets array, moving to the next
- * buckets if we don't find the entry in the current one.
- * Stop when we find an element with version number greater
- * than the current one (we reset the version to 0 when we
- * switch buckets).
- */
- for (; a->bucket < lim; a->bucket++, a->version = 0) {
- /* scan the current bucket */
- AST_LIST_TRAVERSE(&a->c->buckets[a->bucket], p, entry) {
- if (p->version > a->version)
- goto found;
- }
- }
-
-found:
- if (p) {
- a->version = p->version;
- a->obj = p;
- a->c_version = a->c->version;
- ret = EXTERNAL_OBJ(p->astobj);
- /* inc refcount of returned object */
- ao2_ref(ret, 1);
- }
-
- if (!(a->flags & F_AO2I_DONTLOCK))
- ao2_unlock(a->c);
-
- return ret;
-}
-
-/* callback for destroying container.
- * we can make it simple as we know what it does
- */
-static int cd_cb(void *obj, void *arg, int flag)
-{
- ao2_ref(obj, -1);
- return 0;
-}
-
-static void container_destruct(void *_c)
-{
- struct ao2_container *c = _c;
- int i;
-
- ao2_callback(c, OBJ_UNLINK, cd_cb, NULL);
-
- for (i = 0; i < c->n_buckets; i++) {
- struct bucket_list *cur;
-
- while ((cur = AST_LIST_REMOVE_HEAD(&c->buckets[i], entry))) {
- ast_free(cur);
- }
- }
-
-#ifdef AO2_DEBUG
- ast_atomic_fetchadd_int(&ao2.total_containers, -1);
-#endif
-}
-
-#ifdef AO2_DEBUG
-static int print_cb(void *obj, void *arg, int flag)
-{
- int *fd = arg;
- char *s = (char *)obj;
-
- ast_cli(*fd, "string <%s>\n", s);
- return 0;
-}
-
-/*
- * Print stats
- */
-static int handle_astobj2_stats(int fd, int argc, char *argv[])
-{
- ast_cli(fd, "Objects : %d\n", ao2.total_objects);
- ast_cli(fd, "Containers : %d\n", ao2.total_containers);
- ast_cli(fd, "Memory : %d\n", ao2.total_mem);
- ast_cli(fd, "Locked : %d\n", ao2.total_locked);
- ast_cli(fd, "Refs : %d\n", ao2.total_refs);
- return 0;
-}
-
-/*
- * This is testing code for astobj
- */
-static int handle_astobj2_test(int fd, int argc, char *argv[])
-{
- struct ao2_container *c1;
- int i, lim;
- char *obj;
- static int prof_id = -1;
-
- if (prof_id == -1)
- prof_id = ast_add_profile("ao2_alloc", 0);
-
- ast_cli(fd, "argc %d argv %s %s %s\n", argc, argv[0], argv[1], argv[2]);
- lim = atoi(argv[2]);
- ast_cli(fd, "called astobj_test\n");
-
- handle_astobj2_stats(fd, 0, NULL);
- /*
- * allocate a container with no default callback, and no hash function.
- * No hash means everything goes in the same bucket.
- */
- c1 = ao2_container_alloc(100, NULL /* no callback */, NULL /* no hash */);
- ast_cli(fd, "container allocated as %p\n", c1);
-
- /*
- * fill the container with objects.
- * ao2_alloc() gives us a reference which we pass to the
- * container when we do the insert.
- */
- for (i = 0; i < lim; i++) {
- ast_mark(prof_id, 1 /* start */);
- obj = ao2_alloc(80, NULL);
- ast_mark(prof_id, 0 /* stop */);
- ast_cli(fd, "object %d allocated as %p\n", i, obj);
- sprintf(obj, "-- this is obj %d --", i);
- ao2_link(c1, obj);
- }
- ast_cli(fd, "testing callbacks\n");
- ao2_callback(c1, 0, print_cb, &fd);
-
- ast_cli(fd, "testing iterators, remove every second object\n");
- {
- struct ao2_iterator ai;
- int x = 0;
-
- ai = ao2_iterator_init(c1, 0);
- while ( (obj = ao2_iterator_next(&ai)) ) {
- ast_cli(fd, "iterator on <%s>\n", obj);
- if (x++ & 1)
- ao2_unlink(c1, obj);
- ao2_ref(obj, -1);
- }
- ast_cli(fd, "testing iterators again\n");
- ai = ao2_iterator_init(c1, 0);
- while ( (obj = ao2_iterator_next(&ai)) ) {
- ast_cli(fd, "iterator on <%s>\n", obj);
- ao2_ref(obj, -1);
- }
- }
- ast_cli(fd, "testing callbacks again\n");
- ao2_callback(c1, 0, print_cb, &fd);
-
- ast_verbose("now you should see an error message:\n");
- ao2_ref(&i, -1); /* i is not a valid object so we print an error here */
-
- ast_cli(fd, "destroy container\n");
- ao2_ref(c1, -1); /* destroy container */
- handle_astobj2_stats(fd, 0, NULL);
- return 0;
-}
-
-static struct ast_cli_entry cli_astobj2[] = {
- { { "astobj2", "stats", NULL },
- handle_astobj2_stats, "Print astobj2 statistics", },
- { { "astobj2", "test", NULL } , handle_astobj2_test, "Test astobj2", },
-};
-#endif /* AO2_DEBUG */
-
-int astobj2_init(void)
-{
-#ifdef AO2_DEBUG
- ast_cli_register_multiple(cli_astobj2, ARRAY_LEN(cli_astobj2));
-#endif
-
- return 0;
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-12 21:49:21 +0000