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Asterisk developer's documentation


taskprocessor.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 2007-2008, Dwayne M. Hubbard 
00005  *
00006  * Dwayne M. Hubbard <dhubbard@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 /*! \file
00019  *
00020  * \brief Maintain a container of uniquely-named taskprocessor threads that can be shared across modules.
00021  *
00022  * \author Dwayne Hubbard <dhubbard@digium.com>
00023  */
00024 
00025 #include "asterisk.h"
00026 
00027 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 185947 $")
00028 
00029 #include <signal.h>
00030 #include <sys/time.h>
00031 
00032 #include "asterisk/_private.h"
00033 #include "asterisk/module.h"
00034 #include "asterisk/time.h"
00035 #include "asterisk/astobj2.h"
00036 #include "asterisk/cli.h"
00037 #include "asterisk/taskprocessor.h"
00038 
00039 
00040 /*! \brief tps_task structure is queued to a taskprocessor
00041  *
00042  * tps_tasks are processed in FIFO order and freed by the taskprocessing
00043  * thread after the task handler returns.  The callback function that is assigned
00044  * to the execute() function pointer is responsible for releasing datap resources if necessary. */
00045 struct tps_task {
00046    /*! \brief The execute() task callback function pointer */
00047    int (*execute)(void *datap);
00048    /*! \brief The data pointer for the task execute() function */
00049    void *datap;
00050    /*! \brief AST_LIST_ENTRY overhead */
00051    AST_LIST_ENTRY(tps_task) list;
00052 };
00053 
00054 /*! \brief tps_taskprocessor_stats maintain statistics for a taskprocessor. */
00055 struct tps_taskprocessor_stats {
00056    /*! \brief This is the maximum number of tasks queued at any one time */
00057    unsigned long max_qsize;
00058    /*! \brief This is the current number of tasks processed */
00059    unsigned long _tasks_processed_count;
00060 };
00061 
00062 /*! \brief A ast_taskprocessor structure is a singleton by name */
00063 struct ast_taskprocessor {
00064    /*! \brief Friendly name of the taskprocessor */
00065    char *name;
00066    /*! \brief Thread poll condition */
00067    ast_cond_t poll_cond;
00068    /*! \brief Taskprocessor thread */
00069    pthread_t poll_thread;
00070    /*! \brief Taskprocessor lock */
00071    ast_mutex_t taskprocessor_lock;
00072    /*! \brief Taskprocesor thread run flag */
00073    unsigned char poll_thread_run;
00074    /*! \brief Taskprocessor statistics */
00075    struct tps_taskprocessor_stats *stats;
00076    /*! \brief Taskprocessor current queue size */
00077    long tps_queue_size;
00078    /*! \brief Taskprocessor queue */
00079    AST_LIST_HEAD_NOLOCK(tps_queue, tps_task) tps_queue;
00080    /*! \brief Taskprocessor singleton list entry */
00081    AST_LIST_ENTRY(ast_taskprocessor) list;
00082 };
00083 #define TPS_MAX_BUCKETS 7
00084 /*! \brief tps_singletons is the astobj2 container for taskprocessor singletons */
00085 static struct ao2_container *tps_singletons;
00086 
00087 /*! \brief CLI <example>taskprocessor ping &lt;blah&gt;</example> operation requires a ping condition */
00088 static ast_cond_t cli_ping_cond;
00089 
00090 /*! \brief CLI <example>taskprocessor ping &lt;blah&gt;</example> operation requires a ping condition lock */
00091 AST_MUTEX_DEFINE_STATIC(cli_ping_cond_lock);
00092 
00093 /*! \brief The astobj2 hash callback for taskprocessors */
00094 static int tps_hash_cb(const void *obj, const int flags);
00095 /*! \brief The astobj2 compare callback for taskprocessors */
00096 static int tps_cmp_cb(void *obj, void *arg, int flags);
00097 
00098 /*! \brief The task processing function executed by a taskprocessor */
00099 static void *tps_processing_function(void *data);
00100 
00101 /*! \brief Destroy the taskprocessor when its refcount reaches zero */
00102 static void tps_taskprocessor_destroy(void *tps);
00103 
00104 /*! \brief CLI <example>taskprocessor ping &lt;blah&gt;</example> handler function */
00105 static int tps_ping_handler(void *datap);
00106 
00107 /*! \brief Remove the front task off the taskprocessor queue */
00108 static struct tps_task *tps_taskprocessor_pop(struct ast_taskprocessor *tps);
00109 
00110 /*! \brief Return the size of the taskprocessor queue */
00111 static int tps_taskprocessor_depth(struct ast_taskprocessor *tps);
00112 
00113 static char *cli_tps_ping(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a);
00114 static char *cli_tps_report(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a);
00115 
00116 static struct ast_cli_entry taskprocessor_clis[] = {
00117    AST_CLI_DEFINE(cli_tps_ping, "Ping a named task processor"),
00118    AST_CLI_DEFINE(cli_tps_report, "List instantiated task processors and statistics"),
00119 };
00120 
00121 /* initialize the taskprocessor container and register CLI operations */
00122 int ast_tps_init(void)
00123 {
00124    if (!(tps_singletons = ao2_container_alloc(TPS_MAX_BUCKETS, tps_hash_cb, tps_cmp_cb))) {
00125       ast_log(LOG_ERROR, "taskprocessor container failed to initialize!\n");
00126       return -1;
00127    }
00128 
00129    ast_cond_init(&cli_ping_cond, NULL);
00130 
00131    ast_cli_register_multiple(taskprocessor_clis, ARRAY_LEN(taskprocessor_clis));
00132    return 0;
00133 }
00134 
00135 /* allocate resources for the task */
00136 static struct tps_task *tps_task_alloc(int (*task_exe)(void *datap), void *datap)
00137 {
00138    struct tps_task *t;
00139    if ((t = ast_calloc(1, sizeof(*t)))) {
00140       t->execute = task_exe;
00141       t->datap = datap;
00142    }
00143    return t;
00144 }
00145 
00146 /* release task resources */  
00147 static void *tps_task_free(struct tps_task *task)
00148 {
00149    if (task) {
00150       ast_free(task);
00151    }
00152    return NULL;
00153 }
00154 
00155 /* taskprocessor tab completion */
00156 static char *tps_taskprocessor_tab_complete(struct ast_taskprocessor *p, struct ast_cli_args *a) 
00157 {
00158    int tklen;
00159    int wordnum = 0;
00160    char *name = NULL;
00161    struct ao2_iterator i;
00162 
00163    if (a->pos != 3)
00164       return NULL;
00165 
00166    tklen = strlen(a->word);
00167    i = ao2_iterator_init(tps_singletons, 0);
00168    while ((p = ao2_iterator_next(&i))) {
00169       if (!strncasecmp(a->word, p->name, tklen) && ++wordnum > a->n) {
00170          name = ast_strdup(p->name);
00171          ao2_ref(p, -1);
00172          break;
00173       }
00174       ao2_ref(p, -1);
00175    }
00176    return name;
00177 }
00178 
00179 /* ping task handling function */
00180 static int tps_ping_handler(void *datap)
00181 {
00182    ast_mutex_lock(&cli_ping_cond_lock);
00183    ast_cond_signal(&cli_ping_cond);
00184    ast_mutex_unlock(&cli_ping_cond_lock);
00185    return 0;
00186 }
00187 
00188 /* ping the specified taskprocessor and display the ping time on the CLI */
00189 static char *cli_tps_ping(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
00190 {
00191    struct timeval begin, end, delta;
00192    char *name;
00193    struct timeval when;
00194    struct timespec ts;
00195    struct ast_taskprocessor *tps = NULL;
00196 
00197    switch (cmd) {
00198    case CLI_INIT:
00199       e->command = "core ping taskprocessor";
00200       e->usage = 
00201          "Usage: core ping taskprocessor <taskprocessor>\n"
00202          "  Displays the time required for a task to be processed\n";
00203       return NULL;
00204    case CLI_GENERATE:
00205       return tps_taskprocessor_tab_complete(tps, a);
00206    }
00207 
00208    if (a->argc != 4)
00209       return CLI_SHOWUSAGE;
00210 
00211    name = a->argv[3];
00212    if (!(tps = ast_taskprocessor_get(name, TPS_REF_IF_EXISTS))) {
00213       ast_cli(a->fd, "\nping failed: %s not found\n\n", name);
00214       return CLI_SUCCESS;
00215    }
00216    ast_cli(a->fd, "\npinging %s ...", name);
00217    when = ast_tvadd((begin = ast_tvnow()), ast_samp2tv(1000, 1000));
00218    ts.tv_sec = when.tv_sec;
00219    ts.tv_nsec = when.tv_usec * 1000;
00220    ast_mutex_lock(&cli_ping_cond_lock);
00221    if (ast_taskprocessor_push(tps, tps_ping_handler, 0) < 0) {
00222       ast_cli(a->fd, "\nping failed: could not push task to %s\n\n", name);
00223       ao2_ref(tps, -1);
00224       return CLI_FAILURE;
00225    }
00226    ast_cond_timedwait(&cli_ping_cond, &cli_ping_cond_lock, &ts);
00227    ast_mutex_unlock(&cli_ping_cond_lock);
00228    end = ast_tvnow();
00229    delta = ast_tvsub(end, begin);
00230    ast_cli(a->fd, "\n\t%24s ping time: %.1ld.%.6ld sec\n\n", name, (long)delta.tv_sec, (long int)delta.tv_usec);
00231    ao2_ref(tps, -1);
00232    return CLI_SUCCESS;  
00233 }
00234 
00235 static char *cli_tps_report(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
00236 {
00237    char name[256];
00238    int tcount;
00239    unsigned long qsize;
00240    unsigned long maxqsize;
00241    unsigned long processed;
00242    struct ast_taskprocessor *p;
00243    struct ao2_iterator i;
00244 
00245    switch (cmd) {
00246    case CLI_INIT:
00247       e->command = "core show taskprocessors";
00248       e->usage = 
00249          "Usage: core show taskprocessors\n"
00250          "  Shows a list of instantiated task processors and their statistics\n";
00251       return NULL;
00252    case CLI_GENERATE:
00253       return NULL;   
00254    }
00255 
00256    if (a->argc != e->args)
00257       return CLI_SHOWUSAGE;
00258 
00259    ast_cli(a->fd, "\n\t+----- Processor -----+--- Processed ---+- In Queue -+- Max Depth -+");
00260    i = ao2_iterator_init(tps_singletons, 0);
00261    while ((p = ao2_iterator_next(&i))) {
00262       ast_copy_string(name, p->name, sizeof(name));
00263       qsize = p->tps_queue_size;
00264       maxqsize = p->stats->max_qsize;
00265       processed = p->stats->_tasks_processed_count;
00266       ast_cli(a->fd, "\n%24s   %17ld %12ld %12ld", name, processed, qsize, maxqsize);
00267       ao2_ref(p, -1);
00268    }
00269    tcount = ao2_container_count(tps_singletons); 
00270    ast_cli(a->fd, "\n\t+---------------------+-----------------+------------+-------------+\n\t%d taskprocessors\n\n", tcount);
00271    return CLI_SUCCESS;  
00272 }
00273 
00274 /* this is the task processing worker function */
00275 static void *tps_processing_function(void *data)
00276 {
00277    struct ast_taskprocessor *i = data;
00278    struct tps_task *t;
00279    int size;
00280 
00281    if (!i) {
00282       ast_log(LOG_ERROR, "cannot start thread_function loop without a ast_taskprocessor structure.\n");
00283       return NULL;
00284    }
00285 
00286    while (i->poll_thread_run) {
00287       ast_mutex_lock(&i->taskprocessor_lock);
00288       if (!i->poll_thread_run) {
00289          ast_mutex_unlock(&i->taskprocessor_lock);
00290          break;
00291       }
00292       if (!(size = tps_taskprocessor_depth(i))) {
00293          ast_cond_wait(&i->poll_cond, &i->taskprocessor_lock);
00294          if (!i->poll_thread_run) {
00295             ast_mutex_unlock(&i->taskprocessor_lock);
00296             break;
00297          }
00298       }
00299       ast_mutex_unlock(&i->taskprocessor_lock);
00300       /* stuff is in the queue */
00301       if (!(t = tps_taskprocessor_pop(i))) {
00302          ast_log(LOG_ERROR, "Wtf?? %d tasks in the queue, but we're popping blanks!\n", size);
00303          continue;
00304       }
00305       if (!t->execute) {
00306          ast_log(LOG_WARNING, "Task is missing a function to execute!\n");
00307          tps_task_free(t);
00308          continue;
00309       }
00310       t->execute(t->datap);
00311  
00312       ast_mutex_lock(&i->taskprocessor_lock);
00313       if (i->stats) {
00314          i->stats->_tasks_processed_count++;
00315          if (size > i->stats->max_qsize) {
00316             i->stats->max_qsize = size;
00317          }
00318       }
00319       ast_mutex_unlock(&i->taskprocessor_lock);
00320  
00321       tps_task_free(t);
00322    }
00323    while ((t = tps_taskprocessor_pop(i))) {
00324       tps_task_free(t);
00325    }
00326    return NULL;
00327 }
00328 
00329 /* hash callback for astobj2 */
00330 static int tps_hash_cb(const void *obj, const int flags)
00331 {
00332    const struct ast_taskprocessor *tps = obj;
00333 
00334    return ast_str_case_hash(tps->name);
00335 }
00336 
00337 /* compare callback for astobj2 */
00338 static int tps_cmp_cb(void *obj, void *arg, int flags)
00339 {
00340    struct ast_taskprocessor *lhs = obj, *rhs = arg;
00341 
00342    return !strcasecmp(lhs->name, rhs->name) ? CMP_MATCH | CMP_STOP : 0;
00343 }
00344 
00345 /* destroy the taskprocessor */
00346 static void tps_taskprocessor_destroy(void *tps)
00347 {
00348    struct ast_taskprocessor *t = tps;
00349    
00350    if (!tps) {
00351       ast_log(LOG_ERROR, "missing taskprocessor\n");
00352       return;
00353    }
00354    ast_log(LOG_DEBUG, "destroying taskprocessor '%s'\n", t->name);
00355    /* kill it */  
00356    ast_mutex_lock(&t->taskprocessor_lock);
00357    t->poll_thread_run = 0;
00358    ast_cond_signal(&t->poll_cond);
00359    ast_mutex_unlock(&t->taskprocessor_lock);
00360    pthread_join(t->poll_thread, NULL);
00361    t->poll_thread = AST_PTHREADT_NULL;
00362    ast_mutex_destroy(&t->taskprocessor_lock);
00363    ast_cond_destroy(&t->poll_cond);
00364    /* free it */
00365    if (t->stats) {
00366       ast_free(t->stats);
00367       t->stats = NULL;
00368    }
00369    ast_free(t->name);
00370 }
00371 
00372 /* pop the front task and return it */
00373 static struct tps_task *tps_taskprocessor_pop(struct ast_taskprocessor *tps)
00374 {
00375    struct tps_task *task;
00376 
00377    if (!tps) {
00378       ast_log(LOG_ERROR, "missing taskprocessor\n");
00379       return NULL;
00380    }
00381    ast_mutex_lock(&tps->taskprocessor_lock);
00382    if ((task = AST_LIST_REMOVE_HEAD(&tps->tps_queue, list))) {
00383       tps->tps_queue_size--;
00384    }
00385    ast_mutex_unlock(&tps->taskprocessor_lock);
00386    return task;
00387 }
00388 
00389 static int tps_taskprocessor_depth(struct ast_taskprocessor *tps)
00390 {
00391    return (tps) ? tps->tps_queue_size : -1;
00392 }
00393 
00394 /* taskprocessor name accessor */
00395 const char *ast_taskprocessor_name(struct ast_taskprocessor *tps)
00396 {
00397    if (!tps) {
00398       ast_log(LOG_ERROR, "no taskprocessor specified!\n");
00399       return NULL;
00400    }
00401    return tps->name;
00402 }
00403 
00404 /* Provide a reference to a taskprocessor.  Create the taskprocessor if necessary, but don't
00405  * create the taskprocessor if we were told via ast_tps_options to return a reference only 
00406  * if it already exists */
00407 struct ast_taskprocessor *ast_taskprocessor_get(char *name, enum ast_tps_options create)
00408 {
00409    struct ast_taskprocessor *p, tmp_tps = {
00410       .name = name,
00411    };
00412       
00413    if (ast_strlen_zero(name)) {
00414       ast_log(LOG_ERROR, "requesting a nameless taskprocessor!!!\n");
00415       return NULL;
00416    }
00417    ao2_lock(tps_singletons);
00418    p = ao2_find(tps_singletons, &tmp_tps, OBJ_POINTER);
00419    if (p) {
00420       ao2_unlock(tps_singletons);
00421       return p;
00422    }
00423    if (create & TPS_REF_IF_EXISTS) {
00424       /* calling function does not want a new taskprocessor to be created if it doesn't already exist */
00425       ao2_unlock(tps_singletons);
00426       return NULL;
00427    }
00428    /* create a new taskprocessor */
00429    if (!(p = ao2_alloc(sizeof(*p), tps_taskprocessor_destroy))) {
00430       ao2_unlock(tps_singletons);
00431       ast_log(LOG_WARNING, "failed to create taskprocessor '%s'\n", name);
00432       return NULL;
00433    }
00434 
00435    ast_cond_init(&p->poll_cond, NULL);
00436    ast_mutex_init(&p->taskprocessor_lock);
00437 
00438    if (!(p->stats = ast_calloc(1, sizeof(*p->stats)))) {
00439       ao2_unlock(tps_singletons);
00440       ast_log(LOG_WARNING, "failed to create taskprocessor stats for '%s'\n", name);
00441       ao2_ref(p, -1);
00442       return NULL;
00443    }
00444    if (!(p->name = ast_strdup(name))) {
00445       ao2_unlock(tps_singletons);
00446       ao2_ref(p, -1);
00447       return NULL;
00448    }
00449    p->poll_thread_run = 1;
00450    p->poll_thread = AST_PTHREADT_NULL;
00451    if (ast_pthread_create(&p->poll_thread, NULL, tps_processing_function, p) < 0) {
00452       ao2_unlock(tps_singletons);
00453       ast_log(LOG_ERROR, "Taskprocessor '%s' failed to create the processing thread.\n", p->name);
00454       ao2_ref(p, -1);
00455       return NULL;
00456    }
00457    if (!(ao2_link(tps_singletons, p))) {
00458       ao2_unlock(tps_singletons);
00459       ast_log(LOG_ERROR, "Failed to add taskprocessor '%s' to container\n", p->name);
00460       ao2_ref(p, -1);
00461       return NULL;
00462    }
00463    ao2_unlock(tps_singletons);
00464    return p;
00465 }
00466 
00467 /* decrement the taskprocessor reference count and unlink from the container if necessary */
00468 void *ast_taskprocessor_unreference(struct ast_taskprocessor *tps)
00469 {
00470    if (tps) {
00471       ao2_lock(tps_singletons);
00472       ao2_unlink(tps_singletons, tps);
00473       if (ao2_ref(tps, -1) > 1) {
00474          ao2_link(tps_singletons, tps);
00475       }
00476       ao2_unlock(tps_singletons);
00477    }
00478    return NULL;
00479 }
00480 
00481 /* push the task into the taskprocessor queue */   
00482 int ast_taskprocessor_push(struct ast_taskprocessor *tps, int (*task_exe)(void *datap), void *datap)
00483 {
00484    struct tps_task *t;
00485 
00486    if (!tps || !task_exe) {
00487       ast_log(LOG_ERROR, "%s is missing!!\n", (tps) ? "task callback" : "taskprocessor");
00488       return -1;
00489    }
00490    if (!(t = tps_task_alloc(task_exe, datap))) {
00491       ast_log(LOG_ERROR, "failed to allocate task!  Can't push to '%s'\n", tps->name);
00492       return -1;
00493    }
00494    ast_mutex_lock(&tps->taskprocessor_lock);
00495    AST_LIST_INSERT_TAIL(&tps->tps_queue, t, list);
00496    tps->tps_queue_size++;
00497    ast_cond_signal(&tps->poll_cond);
00498    ast_mutex_unlock(&tps->taskprocessor_lock);
00499    return 0;
00500 }
00501