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astobj2.c

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00001 /*
00002  * astobj2 - replacement containers for asterisk data structures.
00003  *
00004  * Copyright (C) 2006 Marta Carbone, Luigi Rizzo - Univ. di Pisa, Italy
00005  *
00006  * See http://www.asterisk.org for more information about
00007  * the Asterisk project. Please do not directly contact
00008  * any of the maintainers of this project for assistance;
00009  * the project provides a web site, mailing lists and IRC
00010  * channels for your use.
00011  *
00012  * This program is free software, distributed under the terms of
00013  * the GNU General Public License Version 2. See the LICENSE file
00014  * at the top of the source tree.
00015  */
00016 
00017 /*
00018  * Function implementing astobj2 objects.
00019  */
00020 
00021 /*** MODULEINFO
00022    <support_level>core</support_level>
00023  ***/
00024 
00025 #include "asterisk.h"
00026 
00027 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 424786 $")
00028 
00029 #include "asterisk/_private.h"
00030 #include "asterisk/astobj2.h"
00031 #include "asterisk/utils.h"
00032 #include "asterisk/cli.h"
00033 #include "asterisk/paths.h"
00034 
00035 static FILE *ref_log;
00036 
00037 /*!
00038  * astobj2 objects are always preceded by this data structure,
00039  * which contains a lock, a reference counter,
00040  * the flags and a pointer to a destructor.
00041  * The refcount is used to decide when it is time to
00042  * invoke the destructor.
00043  * The magic number is used for consistency check.
00044  * XXX the lock is not always needed, and its initialization may be
00045  * expensive. Consider making it external.
00046  */
00047 struct __priv_data {
00048    ast_mutex_t lock;
00049    int ref_counter;
00050    ao2_destructor_fn destructor_fn;
00051    /*! for stats */
00052    size_t data_size;
00053    /*! magic number.  This is used to verify that a pointer passed in is a
00054     *  valid astobj2 */
00055    uint32_t magic;
00056 };
00057 
00058 #define  AO2_MAGIC   0xa570b123
00059 
00060 /*!
00061  * What an astobj2 object looks like: fixed-size private data
00062  * followed by variable-size user data.
00063  */
00064 struct astobj2 {
00065    struct __priv_data priv_data;
00066    void *user_data[0];
00067 };
00068 
00069 #ifdef AST_DEVMODE
00070 /* #define AO2_DEBUG 1 */
00071 #endif
00072 
00073 #ifdef AO2_DEBUG
00074 struct ao2_stats {
00075    volatile int total_objects;
00076    volatile int total_mem;
00077    volatile int total_containers;
00078    volatile int total_refs;
00079    volatile int total_locked;
00080 };
00081 
00082 static struct ao2_stats ao2;
00083 #endif
00084 
00085 #ifndef HAVE_BKTR /* backtrace support */
00086 void ao2_bt(void) {}
00087 #else
00088 #include <execinfo.h>    /* for backtrace */
00089 
00090 void ao2_bt(void)
00091 {
00092    int c, i;
00093 #define N1  20
00094    void *addresses[N1];
00095    char **strings;
00096 
00097    c = backtrace(addresses, N1);
00098    strings = ast_bt_get_symbols(addresses,c);
00099    ast_verbose("backtrace returned: %d\n", c);
00100    for(i = 0; i < c; i++) {
00101       ast_verbose("%d: %p %s\n", i, addresses[i], strings[i]);
00102    }
00103    ast_std_free(strings);
00104 }
00105 #endif
00106 
00107 /*!
00108  * \brief convert from a pointer _p to a user-defined object
00109  *
00110  * \return the pointer to the astobj2 structure
00111  */
00112 static inline struct astobj2 *INTERNAL_OBJ(void *user_data)
00113 {
00114    struct astobj2 *p;
00115 
00116    if (!user_data) {
00117       ast_log(LOG_ERROR, "user_data is NULL\n");
00118       return NULL;
00119    }
00120 
00121    p = (struct astobj2 *) ((char *) user_data - sizeof(*p));
00122    if (AO2_MAGIC != p->priv_data.magic) {
00123       if (p->priv_data.magic) {
00124          ast_log(LOG_ERROR, "bad magic number 0x%x for object %p\n",
00125             p->priv_data.magic, user_data);
00126       } else {
00127          ast_log(LOG_ERROR,
00128             "bad magic number for object %p. Object is likely destroyed.\n",
00129             user_data);
00130       }
00131       ast_assert(0);
00132       return NULL;
00133    }
00134 
00135    return p;
00136 }
00137 
00138 enum ao2_callback_type {
00139    DEFAULT,
00140    WITH_DATA,
00141 };
00142 
00143 /*!
00144  * \brief convert from a pointer _p to an astobj2 object
00145  *
00146  * \return the pointer to the user-defined portion.
00147  */
00148 #define EXTERNAL_OBJ(_p)   ((_p) == NULL ? NULL : (_p)->user_data)
00149 
00150 /* the underlying functions common to debug and non-debug versions */
00151 
00152 static int internal_ao2_ref(void *user_data, const int delta);
00153 static struct ao2_container *internal_ao2_container_alloc(struct ao2_container *c, const uint n_buckets, ao2_hash_fn *hash_fn,
00154                        ao2_callback_fn *cmp_fn);
00155 static struct bucket_entry *internal_ao2_link(struct ao2_container *c, void *user_data, const char *file, int line, const char *func);
00156 static void *internal_ao2_callback(struct ao2_container *c,
00157                const enum search_flags flags, void *cb_fn, void *arg, void *data, enum ao2_callback_type type,
00158                char *tag, char *file, int line, const char *funcname);
00159 static void *internal_ao2_iterator_next(struct ao2_iterator *a, struct bucket_entry **q);
00160 
00161 int __ao2_lock(void *user_data, const char *file, const char *func, int line, const char *var)
00162 {
00163    struct astobj2 *p = INTERNAL_OBJ(user_data);
00164 
00165    if (p == NULL)
00166       return -1;
00167 
00168 #ifdef AO2_DEBUG
00169    ast_atomic_fetchadd_int(&ao2.total_locked, 1);
00170 #endif
00171 
00172    return __ast_pthread_mutex_lock(file, line, func, var, &p->priv_data.lock);
00173 }
00174 
00175 int __ao2_unlock(void *user_data, const char *file, const char *func, int line, const char *var)
00176 {
00177    struct astobj2 *p = INTERNAL_OBJ(user_data);
00178 
00179    if (p == NULL)
00180       return -1;
00181 
00182 #ifdef AO2_DEBUG
00183    ast_atomic_fetchadd_int(&ao2.total_locked, -1);
00184 #endif
00185 
00186    return __ast_pthread_mutex_unlock(file, line, func, var, &p->priv_data.lock);
00187 }
00188 
00189 int __ao2_trylock(void *user_data, const char *file, const char *func, int line, const char *var)
00190 {
00191    struct astobj2 *p = INTERNAL_OBJ(user_data);
00192    int ret;
00193    
00194    if (p == NULL)
00195       return -1;
00196    ret = __ast_pthread_mutex_trylock(file, line, func, var, &p->priv_data.lock);
00197 
00198 #ifdef AO2_DEBUG
00199    if (!ret)
00200       ast_atomic_fetchadd_int(&ao2.total_locked, 1);
00201 #endif
00202    return ret;
00203 }
00204 
00205 void *ao2_object_get_lockaddr(void *obj)
00206 {
00207    struct astobj2 *p = INTERNAL_OBJ(obj);
00208    
00209    if (p == NULL)
00210       return NULL;
00211 
00212    return &p->priv_data.lock;
00213 }
00214 
00215 /*
00216  * The argument is a pointer to the user portion.
00217  */
00218 
00219 int __ao2_ref_debug(void *user_data, const int delta, const char *tag, const char *file, int line, const char *funcname)
00220 {
00221    struct astobj2 *obj = INTERNAL_OBJ(user_data);
00222    int old_refcount = -1;
00223 
00224    if (obj) {
00225       old_refcount = internal_ao2_ref(user_data, delta);
00226    }
00227 
00228    if (ref_log && user_data) {
00229       if (!obj) {
00230          /* Invalid object: Bad magic number. */
00231          fprintf(ref_log, "%p,%d,%d,%s,%d,%s,**invalid**,%s\n",
00232             user_data, delta, ast_get_tid(), file, line, funcname, tag);
00233          fflush(ref_log);
00234       } else if (old_refcount + delta == 0) {
00235          fprintf(ref_log, "%p,%d,%d,%s,%d,%s,**destructor**,%s\n",
00236             user_data, delta, ast_get_tid(), file, line, funcname, tag);
00237          fflush(ref_log);
00238       } else if (delta != 0) {
00239          fprintf(ref_log, "%p,%s%d,%d,%s,%d,%s,%d,%s\n", user_data, (delta < 0 ? "" : "+"),
00240             delta, ast_get_tid(), file, line, funcname, old_refcount, tag);
00241          fflush(ref_log);
00242       }
00243    }
00244 
00245    return old_refcount;
00246 }
00247 
00248 int __ao2_ref(void *user_data, const int delta)
00249 {
00250    return internal_ao2_ref(user_data, delta);
00251 }
00252 
00253 static int internal_ao2_ref(void *user_data, const int delta)
00254 {
00255    struct astobj2 *obj = INTERNAL_OBJ(user_data);
00256    int current_value;
00257    int ret;
00258 
00259    if (obj == NULL)
00260       return -1;
00261 
00262    /* if delta is 0, just return the refcount */
00263    if (delta == 0)
00264       return (obj->priv_data.ref_counter);
00265 
00266    /* we modify with an atomic operation the reference counter */
00267    ret = ast_atomic_fetchadd_int(&obj->priv_data.ref_counter, delta);
00268    current_value = ret + delta;
00269 
00270 #ifdef AO2_DEBUG  
00271    ast_atomic_fetchadd_int(&ao2.total_refs, delta);
00272 #endif
00273 
00274    /* this case must never happen */
00275    if (current_value < 0)
00276       ast_log(LOG_ERROR, "refcount %d on object %p\n", current_value, user_data);
00277 
00278    if (current_value <= 0) { /* last reference, destroy the object */
00279       if (obj->priv_data.destructor_fn != NULL) {
00280          obj->priv_data.destructor_fn(user_data);
00281       }
00282 
00283       ast_mutex_destroy(&obj->priv_data.lock);
00284 #ifdef AO2_DEBUG
00285       ast_atomic_fetchadd_int(&ao2.total_mem, - obj->priv_data.data_size);
00286       ast_atomic_fetchadd_int(&ao2.total_objects, -1);
00287 #endif
00288       /* for safety, zero-out the astobj2 header and also the
00289        * first word of the user-data, which we make sure is always
00290        * allocated. */
00291       memset(obj, '\0', sizeof(struct astobj2 *) + sizeof(void *) );
00292       ast_free(obj);
00293    }
00294 
00295    return ret;
00296 }
00297 
00298 /*
00299  * We always alloc at least the size of a void *,
00300  * for debugging purposes.
00301  */
00302 static void *internal_ao2_alloc(size_t data_size, ao2_destructor_fn destructor_fn, const char *file, int line, const char *funcname)
00303 {
00304    /* allocation */
00305    struct astobj2 *obj;
00306 
00307    if (data_size < sizeof(void *))
00308       data_size = sizeof(void *);
00309 
00310 #if defined(__AST_DEBUG_MALLOC)
00311    obj = __ast_calloc(1, sizeof(*obj) + data_size, file, line, funcname);
00312 #else
00313    obj = ast_calloc(1, sizeof(*obj) + data_size);
00314 #endif
00315 
00316    if (obj == NULL)
00317       return NULL;
00318 
00319    ast_mutex_init(&obj->priv_data.lock);
00320    obj->priv_data.magic = AO2_MAGIC;
00321    obj->priv_data.data_size = data_size;
00322    obj->priv_data.ref_counter = 1;
00323    obj->priv_data.destructor_fn = destructor_fn;   /* can be NULL */
00324 
00325 #ifdef AO2_DEBUG
00326    ast_atomic_fetchadd_int(&ao2.total_objects, 1);
00327    ast_atomic_fetchadd_int(&ao2.total_mem, data_size);
00328    ast_atomic_fetchadd_int(&ao2.total_refs, 1);
00329 #endif
00330 
00331    /* return a pointer to the user data */
00332    return EXTERNAL_OBJ(obj);
00333 }
00334 
00335 void *__ao2_alloc_debug(size_t data_size, ao2_destructor_fn destructor_fn, char *tag,
00336          const char *file, int line, const char *funcname, int ref_debug)
00337 {
00338    /* allocation */
00339    void *obj;
00340 
00341    if ((obj = internal_ao2_alloc(data_size, destructor_fn, file, line, funcname)) == NULL) {
00342       return NULL;
00343    }
00344 
00345    if (ref_log) {
00346       fprintf(ref_log, "%p,+1,%d,%s,%d,%s,**constructor**,%s\n", obj, ast_get_tid(), file, line, funcname, tag);
00347       fflush(ref_log);
00348    }
00349 
00350    /* return a pointer to the user data */
00351    return obj;
00352 }
00353 
00354 void *__ao2_alloc(size_t data_size, ao2_destructor_fn destructor_fn)
00355 {
00356    return internal_ao2_alloc(data_size, destructor_fn, __FILE__, __LINE__, __FUNCTION__);
00357 }
00358 
00359 
00360 /* internal callback to destroy a container. */
00361 static void container_destruct(void *c);
00362 
00363 /* internal callback to destroy a container. */
00364 static void container_destruct_debug(void *c);
00365 
00366 /* each bucket in the container is a tailq. */
00367 AST_LIST_HEAD_NOLOCK(bucket, bucket_entry);
00368 
00369 /*!
00370  * A container; stores the hash and callback functions, information on
00371  * the size, the hash bucket heads, and a version number, starting at 0
00372  * (for a newly created, empty container)
00373  * and incremented every time an object is inserted or deleted.
00374  * The assumption is that an object is never moved in a container,
00375  * but removed and readded with the new number.
00376  * The version number is especially useful when implementing iterators.
00377  * In fact, we can associate a unique, monotonically increasing number to
00378  * each object, which means that, within an iterator, we can store the
00379  * version number of the current object, and easily look for the next one,
00380  * which is the next one in the list with a higher number.
00381  * Since all objects have a version >0, we can use 0 as a marker for
00382  * 'we need the first object in the bucket'.
00383  *
00384  * \todo Linking and unlink objects is typically expensive, as it
00385  * involves a malloc() of a small object which is very inefficient.
00386  * To optimize this, we allocate larger arrays of bucket_entry's
00387  * when we run out of them, and then manage our own freelist.
00388  * This will be more efficient as we can do the freelist management while
00389  * we hold the lock (that we need anyways).
00390  */
00391 struct ao2_container {
00392    ao2_hash_fn *hash_fn;
00393    ao2_callback_fn *cmp_fn;
00394    int n_buckets;
00395    /*! Number of elements in the container */
00396    int elements;
00397    /*! described above */
00398    int version;
00399    /*! variable size */
00400    struct bucket buckets[0];
00401 };
00402  
00403 /*!
00404  * \brief always zero hash function
00405  *
00406  * it is convenient to have a hash function that always returns 0.
00407  * This is basically used when we want to have a container that is
00408  * a simple linked list.
00409  *
00410  * \returns 0
00411  */
00412 static int hash_zero(const void *user_obj, const int flags)
00413 {
00414    return 0;
00415 }
00416 
00417 /*
00418  * A container is just an object, after all!
00419  */
00420 static struct ao2_container *internal_ao2_container_alloc(struct ao2_container *c, const unsigned int n_buckets, ao2_hash_fn *hash_fn,
00421                        ao2_callback_fn *cmp_fn)
00422 {
00423    /* XXX maybe consistency check on arguments ? */
00424    /* compute the container size */
00425 
00426    if (!c)
00427       return NULL;
00428    
00429    c->version = 1;   /* 0 is a reserved value here */
00430    c->n_buckets = hash_fn ? n_buckets : 1;
00431    c->hash_fn = hash_fn ? hash_fn : hash_zero;
00432    c->cmp_fn = cmp_fn;
00433 
00434 #ifdef AO2_DEBUG
00435    ast_atomic_fetchadd_int(&ao2.total_containers, 1);
00436 #endif
00437 
00438    return c;
00439 }
00440 
00441 struct ao2_container *__ao2_container_alloc_debug(const unsigned int n_buckets, ao2_hash_fn *hash_fn,
00442                     ao2_callback_fn *cmp_fn, char *tag, char *file, int line,
00443                     const char *funcname, int ref_debug)
00444 {
00445    /* XXX maybe consistency check on arguments ? */
00446    /* compute the container size */
00447    const unsigned int num_buckets = hash_fn ? n_buckets : 1;
00448    size_t container_size = sizeof(struct ao2_container) + num_buckets * sizeof(struct bucket);
00449    struct ao2_container *c = __ao2_alloc_debug(container_size, ref_debug ? container_destruct_debug : container_destruct, tag, file, line, funcname, ref_debug);
00450 
00451    return internal_ao2_container_alloc(c, num_buckets, hash_fn, cmp_fn);
00452 }
00453 
00454 struct ao2_container *__ao2_container_alloc(const unsigned int n_buckets, ao2_hash_fn *hash_fn,
00455                    ao2_callback_fn *cmp_fn)
00456 {
00457    /* XXX maybe consistency check on arguments ? */
00458    /* compute the container size */
00459 
00460    const unsigned int num_buckets = hash_fn ? n_buckets : 1;
00461    size_t container_size = sizeof(struct ao2_container) + num_buckets * sizeof(struct bucket);
00462    struct ao2_container *c = __ao2_alloc(container_size, container_destruct);
00463 
00464    return internal_ao2_container_alloc(c, num_buckets, hash_fn, cmp_fn);
00465 }
00466 
00467 /*!
00468  * return the number of elements in the container
00469  */
00470 int ao2_container_count(struct ao2_container *c)
00471 {
00472    return c->elements;
00473 }
00474 
00475 /*!
00476  * A structure to create a linked list of entries,
00477  * used within a bucket.
00478  * XXX \todo this should be private to the container code
00479  */
00480 struct bucket_entry {
00481    AST_LIST_ENTRY(bucket_entry) entry;
00482    int version;
00483    struct astobj2 *astobj;    /* pointer to internal data */
00484 }; 
00485 
00486 /*
00487  * link an object to a container
00488  */
00489 
00490 static struct bucket_entry *internal_ao2_link(struct ao2_container *c, void *user_data, const char *file, int line, const char *func)
00491 {
00492    int i;
00493    /* create a new list entry */
00494    struct bucket_entry *p;
00495    struct astobj2 *obj = INTERNAL_OBJ(user_data);
00496 
00497    if (obj == NULL)
00498       return NULL;
00499 
00500    if (INTERNAL_OBJ(c) == NULL)
00501       return NULL;
00502 
00503    p = ast_calloc(1, sizeof(*p));
00504    if (!p)
00505       return NULL;
00506 
00507    i = abs(c->hash_fn(user_data, OBJ_POINTER));
00508 
00509    ao2_lock(c);
00510    i %= c->n_buckets;
00511    p->astobj = obj;
00512    p->version = ast_atomic_fetchadd_int(&c->version, 1);
00513    AST_LIST_INSERT_TAIL(&c->buckets[i], p, entry);
00514    ast_atomic_fetchadd_int(&c->elements, 1);
00515 
00516    /* the last two operations (ao2_ref, ao2_unlock) must be done by the calling func */
00517    return p;
00518 }
00519 
00520 void *__ao2_link_debug(struct ao2_container *c, void *user_data, char *tag, char *file, int line, const char *funcname)
00521 {
00522    struct bucket_entry *p = internal_ao2_link(c, user_data, file, line, funcname);
00523 
00524    if (p) {
00525       __ao2_ref_debug(user_data, +1, tag, file, line, funcname);
00526       ao2_unlock(c);
00527    }
00528    return p;
00529 }
00530 
00531 void *__ao2_link(struct ao2_container *c, void *user_data)
00532 {
00533    struct bucket_entry *p = internal_ao2_link(c, user_data, __FILE__, __LINE__, __PRETTY_FUNCTION__);
00534 
00535    if (p) {
00536       __ao2_ref(user_data, +1);
00537       ao2_unlock(c);
00538    }
00539    return p;
00540 }
00541 
00542 /*!
00543  * \brief another convenience function is a callback that matches on address
00544  */
00545 int ao2_match_by_addr(void *user_data, void *arg, int flags)
00546 {
00547    return (user_data == arg) ? (CMP_MATCH | CMP_STOP) : 0;
00548 }
00549 
00550 /*
00551  * Unlink an object from the container
00552  * and destroy the associated * bucket_entry structure.
00553  */
00554 void *__ao2_unlink_debug(struct ao2_container *c, void *user_data, char *tag,
00555           char *file, int line, const char *funcname)
00556 {
00557    if (INTERNAL_OBJ(user_data) == NULL)   /* safety check on the argument */
00558       return NULL;
00559 
00560    __ao2_callback_debug(c, OBJ_UNLINK | OBJ_POINTER | OBJ_NODATA, ao2_match_by_addr, user_data, tag, file, line, funcname);
00561 
00562    return NULL;
00563 }
00564 
00565 void *__ao2_unlink(struct ao2_container *c, void *user_data)
00566 {
00567    if (INTERNAL_OBJ(user_data) == NULL)   /* safety check on the argument */
00568       return NULL;
00569 
00570    __ao2_callback(c, OBJ_UNLINK | OBJ_POINTER | OBJ_NODATA, ao2_match_by_addr, user_data);
00571 
00572    return NULL;
00573 }
00574 
00575 /*! 
00576  * \brief special callback that matches all 
00577  */ 
00578 static int cb_true(void *user_data, void *arg, int flags)
00579 {
00580    return CMP_MATCH;
00581 }
00582 
00583 /*!
00584  * \brief similar to cb_true, but is an ao2_callback_data_fn instead
00585  */
00586 static int cb_true_data(void *user_data, void *arg, void *data, int flags)
00587 {
00588    return CMP_MATCH;
00589 }
00590 
00591 /*!
00592  * Browse the container using different stategies accoding the flags.
00593  * \return Is a pointer to an object or to a list of object if OBJ_MULTIPLE is 
00594  * specified.
00595  * Luckily, for debug purposes, the added args (tag, file, line, funcname)
00596  * aren't an excessive load to the system, as the callback should not be
00597  * called as often as, say, the ao2_ref func is called.
00598  */
00599 static void *internal_ao2_callback(struct ao2_container *c,
00600                const enum search_flags flags, void *cb_fn, void *arg, void *data, enum ao2_callback_type type,
00601                char *tag, char *file, int line, const char *funcname)
00602 {
00603    int i, start, last;  /* search boundaries */
00604    void *ret = NULL;
00605    ao2_callback_fn *cb_default = NULL;
00606    ao2_callback_data_fn *cb_withdata = NULL;
00607    struct ao2_container *multi_container = NULL;
00608    struct ao2_iterator *multi_iterator = NULL;
00609 
00610    if (INTERNAL_OBJ(c) == NULL)  /* safety check on the argument */
00611       return NULL;
00612 
00613    /*
00614     * This logic is used so we can support OBJ_MULTIPLE with OBJ_NODATA
00615     * turned off.  This if statement checks for the special condition
00616     * where multiple items may need to be returned.
00617     */
00618    if ((flags & (OBJ_MULTIPLE | OBJ_NODATA)) == OBJ_MULTIPLE) {
00619       /* we need to return an ao2_iterator with the results,
00620        * as there could be more than one. the iterator will
00621        * hold the only reference to a container that has all the
00622        * matching objects linked into it, so when the iterator
00623        * is destroyed, the container will be automatically
00624        * destroyed as well.
00625        */
00626       if (!(multi_container = ao2_container_alloc(1, NULL, NULL))) {
00627          return NULL;
00628       }
00629       if (!(multi_iterator = ast_calloc(1, sizeof(*multi_iterator)))) {
00630          ao2_ref(multi_container, -1);
00631          return NULL;
00632       }
00633    }
00634 
00635    /* override the match function if necessary */
00636    if (cb_fn == NULL) { /* if NULL, match everything */
00637       if (type == WITH_DATA) {
00638          cb_withdata = cb_true_data;
00639       } else {
00640          cb_default = cb_true;
00641       }
00642    } else {
00643       /* We do this here to avoid the per object casting penalty (even though
00644          that is probably optimized away anyway). */
00645       if (type == WITH_DATA) {
00646          cb_withdata = cb_fn;
00647       } else {
00648          cb_default = cb_fn;
00649       }
00650    }
00651 
00652    /*
00653     * XXX this can be optimized.
00654     * If we have a hash function and lookup by pointer,
00655     * run the hash function. Otherwise, scan the whole container
00656     * (this only for the time being. We need to optimize this.)
00657     */
00658    if ((flags & OBJ_POINTER)) /* we know hash can handle this case */
00659       start = i = c->hash_fn(arg, flags & OBJ_POINTER) % c->n_buckets;
00660    else        /* don't know, let's scan all buckets */
00661       start = i = -1;      /* XXX this must be fixed later. */
00662 
00663    /* determine the search boundaries: i..last-1 */
00664    if (i < 0) {
00665       start = i = 0;
00666       last = c->n_buckets;
00667    } else if ((flags & OBJ_CONTINUE)) {
00668       last = c->n_buckets;
00669    } else {
00670       last = i + 1;
00671    }
00672 
00673    ao2_lock(c);   /* avoid modifications to the content */
00674 
00675    for (; i < last ; i++) {
00676       /* scan the list with prev-cur pointers */
00677       struct bucket_entry *cur;
00678 
00679       AST_LIST_TRAVERSE_SAFE_BEGIN(&c->buckets[i], cur, entry) {
00680          int match = (CMP_MATCH | CMP_STOP);
00681 
00682          if (type == WITH_DATA) {
00683             match &= cb_withdata(EXTERNAL_OBJ(cur->astobj), arg, data, flags);
00684          } else {
00685             match &= cb_default(EXTERNAL_OBJ(cur->astobj), arg, flags);
00686          }
00687 
00688          /* we found the object, performing operations according flags */
00689          if (match == 0) { /* no match, no stop, continue */
00690             continue;
00691          } else if (match == CMP_STOP) {  /* no match but stop, we are done */
00692             i = last;
00693             break;
00694          }
00695 
00696          /* we have a match (CMP_MATCH) here */
00697          if (!(flags & OBJ_NODATA)) {  /* if must return the object, record the value */
00698             /* it is important to handle this case before the unlink */
00699             ret = EXTERNAL_OBJ(cur->astobj);
00700             if (!(flags & (OBJ_UNLINK | OBJ_MULTIPLE))) {
00701                if (tag)
00702                   __ao2_ref_debug(ret, 1, tag, file, line, funcname);
00703                else
00704                   __ao2_ref(ret, 1);
00705             }
00706          }
00707 
00708          /* If we are in OBJ_MULTIPLE mode and OBJ_NODATE is off, 
00709           * link the object into the container that will hold the results.
00710           */
00711          if (ret && (multi_container != NULL)) {
00712             if (tag) {
00713                __ao2_link_debug(multi_container, ret, tag, file, line, funcname);
00714             } else {
00715                __ao2_link(multi_container, ret);
00716             }
00717             ret = NULL;
00718          }
00719 
00720          if (flags & OBJ_UNLINK) {  /* must unlink */
00721             /* we are going to modify the container, so update version */
00722             ast_atomic_fetchadd_int(&c->version, 1);
00723             AST_LIST_REMOVE_CURRENT(entry);
00724             /* update number of elements */
00725             ast_atomic_fetchadd_int(&c->elements, -1);
00726 
00727             /* - When unlinking and not returning the result, (OBJ_NODATA), the ref from the container
00728              * must be decremented.
00729              * - When unlinking with OBJ_MULTIPLE the ref from the original container
00730              * must be decremented regardless if OBJ_NODATA is used. This is because the result is
00731              * returned in a new container that already holds its own ref for the object. If the ref
00732              * from the original container is not accounted for here a memory leak occurs. */
00733             if (flags & (OBJ_NODATA | OBJ_MULTIPLE)) {
00734                if (tag)
00735                   __ao2_ref_debug(EXTERNAL_OBJ(cur->astobj), -1, tag, file, line, funcname);
00736                else
00737                   __ao2_ref(EXTERNAL_OBJ(cur->astobj), -1);
00738             }
00739             ast_free(cur); /* free the link record */
00740          }
00741 
00742          if ((match & CMP_STOP) || !(flags & OBJ_MULTIPLE)) {
00743             /* We found our only (or last) match, so force an exit from
00744                the outside loop. */
00745             i = last;
00746             break;
00747          }
00748       }
00749       AST_LIST_TRAVERSE_SAFE_END;
00750 
00751       if (ret) {
00752          break;
00753       }
00754 
00755       if (i == c->n_buckets - 1 && (flags & OBJ_POINTER) && (flags & OBJ_CONTINUE)) {
00756          /* Move to the beginning to ensure we check every bucket */
00757          i = -1;
00758          last = start;
00759       }
00760    }
00761    ao2_unlock(c);
00762 
00763    /* if multi_container was created, we are returning multiple objects */
00764    if (multi_container != NULL) {
00765       *multi_iterator = ao2_iterator_init(multi_container,
00766                       AO2_ITERATOR_DONTLOCK | AO2_ITERATOR_UNLINK | AO2_ITERATOR_MALLOCD);
00767       ao2_ref(multi_container, -1);
00768       return multi_iterator;
00769    } else {
00770       return ret;
00771    }
00772 }
00773 
00774 void *__ao2_callback_debug(struct ao2_container *c,
00775             const enum search_flags flags,
00776             ao2_callback_fn *cb_fn, void *arg,
00777             char *tag, char *file, int line, const char *funcname)
00778 {
00779    return internal_ao2_callback(c,flags, cb_fn, arg, NULL, DEFAULT, tag, file, line, funcname);
00780 }
00781 
00782 void *__ao2_callback(struct ao2_container *c, const enum search_flags flags,
00783            ao2_callback_fn *cb_fn, void *arg)
00784 {
00785    return internal_ao2_callback(c,flags, cb_fn, arg, NULL, DEFAULT, NULL, NULL, 0, NULL);
00786 }
00787 
00788 void *__ao2_callback_data_debug(struct ao2_container *c,
00789             const enum search_flags flags,
00790             ao2_callback_data_fn *cb_fn, void *arg, void *data,
00791             char *tag, char *file, int line, const char *funcname)
00792 {
00793    return internal_ao2_callback(c, flags, cb_fn, arg, data, WITH_DATA, tag, file, line, funcname);
00794 }
00795 
00796 void *__ao2_callback_data(struct ao2_container *c, const enum search_flags flags,
00797            ao2_callback_data_fn *cb_fn, void *arg, void *data)
00798 {
00799    return internal_ao2_callback(c, flags, cb_fn, arg, data, WITH_DATA, NULL, NULL, 0, NULL);
00800 }
00801 
00802 /*!
00803  * the find function just invokes the default callback with some reasonable flags.
00804  */
00805 void *__ao2_find_debug(struct ao2_container *c, void *arg, enum search_flags flags, char *tag, char *file, int line, const char *funcname)
00806 {
00807    return __ao2_callback_debug(c, flags, c->cmp_fn, arg, tag, file, line, funcname);
00808 }
00809 
00810 void *__ao2_find(struct ao2_container *c, void *arg, enum search_flags flags)
00811 {
00812    return __ao2_callback(c, flags, c->cmp_fn, arg);
00813 }
00814 
00815 /*!
00816  * initialize an iterator so we start from the first object
00817  */
00818 struct ao2_iterator ao2_iterator_init(struct ao2_container *c, int flags)
00819 {
00820    struct ao2_iterator a = {
00821       .c = c,
00822       .flags = flags
00823    };
00824 
00825    ao2_ref(c, +1);
00826    
00827    return a;
00828 }
00829 
00830 /*!
00831  * destroy an iterator
00832  */
00833 void ao2_iterator_destroy(struct ao2_iterator *i)
00834 {
00835    ao2_ref(i->c, -1);
00836    if (i->flags & AO2_ITERATOR_MALLOCD) {
00837       ast_free(i);
00838    } else {
00839       i->c = NULL;
00840    }
00841 }
00842 
00843 /*
00844  * move to the next element in the container.
00845  */
00846 static void *internal_ao2_iterator_next(struct ao2_iterator *a, struct bucket_entry **q)
00847 {
00848    int lim;
00849    struct bucket_entry *p = NULL;
00850    void *ret = NULL;
00851 
00852    *q = NULL;
00853    
00854    if (INTERNAL_OBJ(a->c) == NULL)
00855       return NULL;
00856 
00857    if (!(a->flags & AO2_ITERATOR_DONTLOCK))
00858       ao2_lock(a->c);
00859 
00860    /* optimization. If the container is unchanged and
00861     * we have a pointer, try follow it
00862     */
00863    if (a->c->version == a->c_version && (p = a->obj)) {
00864       if ((p = AST_LIST_NEXT(p, entry)))
00865          goto found;
00866       /* nope, start from the next bucket */
00867       a->bucket++;
00868       a->version = 0;
00869       a->obj = NULL;
00870    }
00871 
00872    lim = a->c->n_buckets;
00873 
00874    /* Browse the buckets array, moving to the next
00875     * buckets if we don't find the entry in the current one.
00876     * Stop when we find an element with version number greater
00877     * than the current one (we reset the version to 0 when we
00878     * switch buckets).
00879     */
00880    for (; a->bucket < lim; a->bucket++, a->version = 0) {
00881       /* scan the current bucket */
00882       AST_LIST_TRAVERSE(&a->c->buckets[a->bucket], p, entry) {
00883          if (p->version > a->version)
00884             goto found;
00885       }
00886    }
00887 
00888 found:
00889    if (p) {
00890       ret = EXTERNAL_OBJ(p->astobj);
00891       if (a->flags & AO2_ITERATOR_UNLINK) {
00892          /* we are going to modify the container, so update version */
00893          ast_atomic_fetchadd_int(&a->c->version, 1);
00894          AST_LIST_REMOVE(&a->c->buckets[a->bucket], p, entry);
00895          /* update number of elements */
00896          ast_atomic_fetchadd_int(&a->c->elements, -1);
00897          a->version = 0;
00898          a->obj = NULL;
00899          a->c_version = a->c->version;
00900          ast_free(p);
00901       } else {
00902          a->version = p->version;
00903          a->obj = p;
00904          a->c_version = a->c->version;
00905          /* inc refcount of returned object */
00906          *q = p;
00907       }
00908    }
00909 
00910    return ret;
00911 }
00912 
00913 void *__ao2_iterator_next_debug(struct ao2_iterator *a, char *tag, char *file, int line, const char *funcname)
00914 {
00915    struct bucket_entry *p;
00916    void *ret = NULL;
00917 
00918    ret = internal_ao2_iterator_next(a, &p);
00919    
00920    if (p) {
00921       /* inc refcount of returned object */
00922       __ao2_ref_debug(ret, 1, tag, file, line, funcname);
00923    }
00924 
00925    if (!(a->flags & AO2_ITERATOR_DONTLOCK))
00926       ao2_unlock(a->c);
00927 
00928    return ret;
00929 }
00930 
00931 void *__ao2_iterator_next(struct ao2_iterator *a)
00932 {
00933    struct bucket_entry *p = NULL;
00934    void *ret = NULL;
00935 
00936    ret = internal_ao2_iterator_next(a, &p);
00937    
00938    if (p) {
00939       /* inc refcount of returned object */
00940       __ao2_ref(ret, 1);
00941    }
00942 
00943    if (!(a->flags & AO2_ITERATOR_DONTLOCK))
00944       ao2_unlock(a->c);
00945 
00946    return ret;
00947 }
00948 
00949 /* callback for destroying container.
00950  * we can make it simple as we know what it does
00951  */
00952 static int cd_cb(void *obj, void *arg, int flag)
00953 {
00954    __ao2_ref(obj, -1);
00955    return 0;
00956 }
00957    
00958 static int cd_cb_debug(void *obj, void *arg, int flag)
00959 {
00960    __ao2_ref_debug(obj, -1, "deref object via container destroy",  __FILE__, __LINE__, __PRETTY_FUNCTION__);
00961    return 0;
00962 }
00963    
00964 static void container_destruct(void *_c)
00965 {
00966    struct ao2_container *c = _c;
00967    int i;
00968 
00969    __ao2_callback(c, OBJ_UNLINK, cd_cb, NULL);
00970 
00971    for (i = 0; i < c->n_buckets; i++) {
00972       struct bucket_entry *current;
00973 
00974       while ((current = AST_LIST_REMOVE_HEAD(&c->buckets[i], entry))) {
00975          ast_free(current);
00976       }
00977    }
00978 
00979 #ifdef AO2_DEBUG
00980    ast_atomic_fetchadd_int(&ao2.total_containers, -1);
00981 #endif
00982 }
00983 
00984 static void container_destruct_debug(void *_c)
00985 {
00986    struct ao2_container *c = _c;
00987    int i;
00988 
00989    __ao2_callback_debug(c, OBJ_UNLINK, cd_cb_debug, NULL, "container_destruct_debug called", __FILE__, __LINE__, __PRETTY_FUNCTION__);
00990 
00991    for (i = 0; i < c->n_buckets; i++) {
00992       struct bucket_entry *current;
00993 
00994       while ((current = AST_LIST_REMOVE_HEAD(&c->buckets[i], entry))) {
00995          ast_free(current);
00996       }
00997    }
00998 
00999 #ifdef AO2_DEBUG
01000    ast_atomic_fetchadd_int(&ao2.total_containers, -1);
01001 #endif
01002 }
01003 
01004 #ifdef AO2_DEBUG
01005 static int print_cb(void *obj, void *arg, int flag)
01006 {
01007    struct ast_cli_args *a = (struct ast_cli_args *) arg;
01008    char *s = (char *)obj;
01009 
01010    ast_cli(a->fd, "string <%s>\n", s);
01011    return 0;
01012 }
01013 
01014 /*
01015  * Print stats
01016  */
01017 static char *handle_astobj2_stats(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
01018 {
01019    switch (cmd) {
01020    case CLI_INIT:
01021       e->command = "astobj2 show stats";
01022       e->usage = "Usage: astobj2 show stats\n"
01023             "       Show astobj2 show stats\n";
01024       return NULL;
01025    case CLI_GENERATE:
01026       return NULL;
01027    }
01028    ast_cli(a->fd, "Objects    : %d\n", ao2.total_objects);
01029    ast_cli(a->fd, "Containers : %d\n", ao2.total_containers);
01030    ast_cli(a->fd, "Memory     : %d\n", ao2.total_mem);
01031    ast_cli(a->fd, "Locked     : %d\n", ao2.total_locked);
01032    ast_cli(a->fd, "Refs       : %d\n", ao2.total_refs);
01033    return CLI_SUCCESS;
01034 }
01035 
01036 /*
01037  * This is testing code for astobj
01038  */
01039 static char *handle_astobj2_test(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
01040 {
01041    struct ao2_container *c1;
01042    int i, lim;
01043    char *obj;
01044    static int prof_id = -1;
01045    struct ast_cli_args fake_args = { a->fd, 0, NULL };
01046 
01047    switch (cmd) {
01048    case CLI_INIT:
01049       e->command = "astobj2 test";
01050       e->usage = "Usage: astobj2 test <num>\n"
01051             "       Runs astobj2 test. Creates 'num' objects,\n"
01052             "       and test iterators, callbacks and may be other stuff\n";
01053       return NULL;
01054    case CLI_GENERATE:
01055       return NULL;
01056    }
01057 
01058    if (a->argc != 3) {
01059       return CLI_SHOWUSAGE;
01060    }
01061 
01062    if (prof_id == -1)
01063       prof_id = ast_add_profile("ao2_alloc", 0);
01064 
01065    ast_cli(a->fd, "argc %d argv %s %s %s\n", a->argc, a->argv[0], a->argv[1], a->argv[2]);
01066    lim = atoi(a->argv[2]);
01067    ast_cli(a->fd, "called astobj_test\n");
01068 
01069    handle_astobj2_stats(e, CLI_HANDLER, &fake_args);
01070    /*
01071     * allocate a container with no default callback, and no hash function.
01072     * No hash means everything goes in the same bucket.
01073     */
01074    c1 = ao2_t_container_alloc(100, NULL /* no callback */, NULL /* no hash */,"test");
01075    ast_cli(a->fd, "container allocated as %p\n", c1);
01076 
01077    /*
01078     * fill the container with objects.
01079     * ao2_alloc() gives us a reference which we pass to the
01080     * container when we do the insert.
01081     */
01082    for (i = 0; i < lim; i++) {
01083       ast_mark(prof_id, 1 /* start */);
01084       obj = ao2_t_alloc(80, NULL,"test");
01085       ast_mark(prof_id, 0 /* stop */);
01086       ast_cli(a->fd, "object %d allocated as %p\n", i, obj);
01087       sprintf(obj, "-- this is obj %d --", i);
01088       ao2_link(c1, obj);
01089       /* At this point, the refcount on obj is 2 due to the allocation
01090        * and linking. We can go ahead and reduce the refcount by 1
01091        * right here so that when the container is unreffed later, the
01092        * objects will be freed
01093        */
01094       ao2_t_ref(obj, -1, "test");
01095    }
01096    ast_cli(a->fd, "testing callbacks\n");
01097    ao2_t_callback(c1, 0, print_cb, a, "test callback");
01098    ast_cli(a->fd, "testing iterators, remove every second object\n");
01099    {
01100       struct ao2_iterator ai;
01101       int x = 0;
01102 
01103       ai = ao2_iterator_init(c1, 0);
01104       while ( (obj = ao2_t_iterator_next(&ai,"test")) ) {
01105          ast_cli(a->fd, "iterator on <%s>\n", obj);
01106          if (x++ & 1)
01107             ao2_t_unlink(c1, obj,"test");
01108          ao2_t_ref(obj, -1,"test");
01109       }
01110       ao2_iterator_destroy(&ai);
01111       ast_cli(a->fd, "testing iterators again\n");
01112       ai = ao2_iterator_init(c1, 0);
01113       while ( (obj = ao2_t_iterator_next(&ai,"test")) ) {
01114          ast_cli(a->fd, "iterator on <%s>\n", obj);
01115          ao2_t_ref(obj, -1,"test");
01116       }
01117       ao2_iterator_destroy(&ai);
01118    }
01119    ast_cli(a->fd, "testing callbacks again\n");
01120    ao2_t_callback(c1, 0, print_cb, a, "test callback");
01121 
01122    ast_verbose("now you should see an error message:\n");
01123    ao2_t_ref(&i, -1, "");  /* i is not a valid object so we print an error here */
01124 
01125    ast_cli(a->fd, "destroy container\n");
01126    ao2_t_ref(c1, -1, "");  /* destroy container */
01127    handle_astobj2_stats(e, CLI_HANDLER, &fake_args);
01128    return CLI_SUCCESS;
01129 }
01130 
01131 static struct ast_cli_entry cli_astobj2[] = {
01132    AST_CLI_DEFINE(handle_astobj2_stats, "Print astobj2 statistics"),
01133    AST_CLI_DEFINE(handle_astobj2_test, "Test astobj2"),
01134 };
01135 #endif /* AO2_DEBUG */
01136 
01137 static void astobj2_cleanup(void)
01138 {
01139 #ifdef AO2_DEBUG
01140    ast_cli_unregister_multiple(cli_astobj2, ARRAY_LEN(cli_astobj2));
01141 #endif
01142 
01143 #ifdef REF_DEBUG
01144    fclose(ref_log);
01145    ref_log = NULL;
01146 #endif
01147 }
01148 
01149 
01150 int astobj2_init(void)
01151 {
01152 #ifdef REF_DEBUG
01153    char ref_filename[1024];
01154 #endif
01155 
01156 #ifdef REF_DEBUG
01157    snprintf(ref_filename, sizeof(ref_filename), "%s/refs", ast_config_AST_LOG_DIR);
01158    ref_log = fopen(ref_filename, "w");
01159    if (!ref_log) {
01160       ast_log(LOG_ERROR, "Could not open ref debug log file: %s\n", ref_filename);
01161    }
01162 #endif
01163 
01164 #ifdef AO2_DEBUG
01165    ast_cli_register_multiple(cli_astobj2, ARRAY_LEN(cli_astobj2));
01166 #endif
01167 
01168    ast_register_atexit(astobj2_cleanup);
01169    return 0;
01170 }

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