threadstorage.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Kevin P. Fleming <[email protected]>
 *
 * 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.
 */

/*! \file
 *
 * \brief Debugging support for thread-local-storage objects
 *
 * \author Kevin P. Fleming <[email protected]>
 */

/*** MODULEINFO
   <support_level>core</support_level>
 ***/

#include "asterisk.h"
#include "asterisk/_private.h"

#if !defined(DEBUG_THREADLOCALS)

void threadstorage_init(void)
{
}

#else /* !defined(DEBUG_THREADLOCALS) */

#include "asterisk/strings.h"
#include "asterisk/utils.h"
#include "asterisk/threadstorage.h"
#include "asterisk/linkedlists.h"
#include "asterisk/cli.h"

struct tls_object {
   void *key;
   size_t size;
   const char *file;
   const char *function;
   unsigned int line;
   pthread_t thread;
   AST_LIST_ENTRY(tls_object) entry;
};

static AST_LIST_HEAD_NOLOCK_STATIC(tls_objects, tls_object);

/* Allow direct use of pthread_mutex_t and friends */
#undef pthread_mutex_t
#undef pthread_mutex_lock
#undef pthread_mutex_unlock
#undef pthread_mutex_init
#undef pthread_mutex_destroy

/*!
 * \brief lock for the tls_objects list
 *
 * \note We can not use an ast_mutex_t for this.  The reason is that this
 *       lock is used within the context of thread-local data destructors,
 *       and the ast_mutex_* API uses thread-local data.  Allocating more
 *       thread-local data at that point just causes a memory leak.
 */
static pthread_mutex_t threadstoragelock;

void __ast_threadstorage_object_add(void *key, size_t len, const char *file, const char *function, unsigned int line)
{
   struct tls_object *to;

   if (!(to = ast_calloc(1, sizeof(*to))))
      return;

   to->key = key;
   to->size = len;
   to->file = file;
   to->function = function;
   to->line = line;
   to->thread = pthread_self();

   pthread_mutex_lock(&threadstoragelock);
   AST_LIST_INSERT_TAIL(&tls_objects, to, entry);
   pthread_mutex_unlock(&threadstoragelock);
}

void __ast_threadstorage_object_remove(void *key)
{
   struct tls_object *to;

   pthread_mutex_lock(&threadstoragelock);
   AST_LIST_TRAVERSE_SAFE_BEGIN(&tls_objects, to, entry) {
      if (to->key == key) {
         AST_LIST_REMOVE_CURRENT(entry);
         break;
      }
   }
   AST_LIST_TRAVERSE_SAFE_END;
   pthread_mutex_unlock(&threadstoragelock);
   if (to)
      ast_free(to);
}

void __ast_threadstorage_object_replace(void *key_old, void *key_new, size_t len)
{
   struct tls_object *to;

   pthread_mutex_lock(&threadstoragelock);
   AST_LIST_TRAVERSE_SAFE_BEGIN(&tls_objects, to, entry) {
      if (to->key == key_old) {
         to->key = key_new;
         to->size = len;
         break;
      }
   }
   AST_LIST_TRAVERSE_SAFE_END;
   pthread_mutex_unlock(&threadstoragelock);
}

static char *handle_cli_threadstorage_show_allocations(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   const char *fn = NULL;
   size_t len = 0;
   unsigned int count = 0;
   struct tls_object *to;

   switch (cmd) {
   case CLI_INIT:
      e->command = "threadstorage show allocations";
      e->usage =
         "Usage: threadstorage show allocations [<file>]\n"
         "       Dumps a list of all thread-specific memory allocations,\n"
         "       optionally limited to those from a specific file\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (a->argc > 4)
      return CLI_SHOWUSAGE;

   if (a->argc > 3)
      fn = a->argv[3];

   pthread_mutex_lock(&threadstoragelock);

   AST_LIST_TRAVERSE(&tls_objects, to, entry) {
      if (fn && strcasecmp(to->file, fn))
         continue;

      ast_cli(a->fd, "%10d bytes allocated in %20s at line %5d of %25s (thread %p)\n",
         (int) to->size, to->function, to->line, to->file, (void *) to->thread);
      len += to->size;
      count++;
   }

   pthread_mutex_unlock(&threadstoragelock);

   ast_cli(a->fd, "%10d bytes allocated in %d allocation%s\n", (int) len, count, count > 1 ? "s" : "");

   return CLI_SUCCESS;
}

static char *handle_cli_threadstorage_show_summary(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
   const char *fn = NULL;
   size_t len = 0;
   unsigned int count = 0;
   struct tls_object *to;
   struct file {
      const char *name;
      size_t len;
      unsigned int count;
      AST_LIST_ENTRY(file) entry;
   } *file;
   AST_LIST_HEAD_NOLOCK_STATIC(file_summary, file);

   switch (cmd) {
   case CLI_INIT:
      e->command = "threadstorage show summary";
      e->usage =
         "Usage: threadstorage show summary [<file>]\n"
         "       Summarizes thread-specific memory allocations by file, or optionally\n"
         "       by function, if a file is specified\n";
      return NULL;
   case CLI_GENERATE:
      return NULL;
   }

   if (a->argc > 4)
      return CLI_SHOWUSAGE;

   if (a->argc > 3)
      fn = a->argv[3];

   pthread_mutex_lock(&threadstoragelock);

   AST_LIST_TRAVERSE(&tls_objects, to, entry) {
      if (fn && strcasecmp(to->file, fn))
         continue;

      AST_LIST_TRAVERSE(&file_summary, file, entry) {
         if ((!fn && (file->name == to->file)) || (fn && (file->name == to->function)))
            break;
      }

      if (!file) {
         file = ast_alloca(sizeof(*file));
         memset(file, 0, sizeof(*file));
         file->name = fn ? to->function : to->file;
         AST_LIST_INSERT_TAIL(&file_summary, file, entry);
      }

      file->len += to->size;
      file->count++;
   }

   pthread_mutex_unlock(&threadstoragelock);

   AST_LIST_TRAVERSE(&file_summary, file, entry) {
      len += file->len;
      count += file->count;
      if (fn) {
         ast_cli(a->fd, "%10d bytes in %d allocation%ss in function %s\n",
            (int) file->len, file->count, file->count > 1 ? "s" : "", file->name);
      } else {
         ast_cli(a->fd, "%10d bytes in %d allocation%s in file %s\n",
            (int) file->len, file->count, file->count > 1 ? "s" : "", file->name);
      }
   }

   ast_cli(a->fd, "%10d bytes allocated in %d allocation%s\n", (int) len, count, count > 1 ? "s" : "");

   return CLI_SUCCESS;
}

static struct ast_cli_entry cli[] = {
   AST_CLI_DEFINE(handle_cli_threadstorage_show_allocations, "Display outstanding thread local storage allocations"),
   AST_CLI_DEFINE(handle_cli_threadstorage_show_summary,     "Summarize outstanding memory allocations")
};

static void threadstorage_shutdown(void)
{
   ast_cli_unregister_multiple(cli, ARRAY_LEN(cli));
}

void threadstorage_init(void)
{
   pthread_mutex_init(&threadstoragelock, NULL);
   ast_cli_register_multiple(cli, ARRAY_LEN(cli));
   ast_register_cleanup(threadstorage_shutdown);
}

#endif /* !defined(DEBUG_THREADLOCALS) */