lib/frr_pthread.c

   1 /*
   2  * Utilities and interfaces for managing POSIX threads
   3  * Copyright (C) 2017  Cumulus Networks
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; see the file COPYING; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19
  20 #include <zebra.h>
  21 #include <pthread.h>
  22 #include <sched.h>
  23
  24 #include "frr_pthread.h"
  25 #include "memory.h"
  26 #include "hash.h"
  27
  28 DEFINE_MTYPE_STATIC(LIB, FRR_PTHREAD, "FRR POSIX Thread");
  29
  30 static unsigned int next_id = 0;
  31
  32 /* Hash table of all frr_pthreads along with synchronization primitive(s) and
  33  * hash table callbacks.
  34  * ------------------------------------------------------------------------ */
  35 static struct hash *pthread_table;
  36 static pthread_mutex_t pthread_table_mtx = PTHREAD_MUTEX_INITIALIZER;
  37
  38 /* pthread_table->hash_cmp */
  39 static int pthread_table_hash_cmp(const void *value1, const void *value2)
  40 {
  41         const struct frr_pthread *tq1 = value1;
  42         const struct frr_pthread *tq2 = value2;
  43
  44         return (tq1->id == tq2->id);
  45 }
  46
  47 /* pthread_table->hash_key */
  48 static unsigned int pthread_table_hash_key(void *value)
  49 {
  50         return ((struct frr_pthread *)value)->id;
  51 }
  52 /* ------------------------------------------------------------------------ */
  53
  54 void frr_pthread_init()
  55 {
  56         pthread_mutex_lock(&pthread_table_mtx);
  57         {
  58                 pthread_table = hash_create(pthread_table_hash_key,
  59                                             pthread_table_hash_cmp, NULL);
  60         }
  61         pthread_mutex_unlock(&pthread_table_mtx);
  62 }
  63
  64 void frr_pthread_finish()
  65 {
  66         pthread_mutex_lock(&pthread_table_mtx);
  67         {
  68                 hash_clean(pthread_table,
  69                            (void (*)(void *))frr_pthread_destroy);
  70                 hash_free(pthread_table);
  71         }
  72         pthread_mutex_unlock(&pthread_table_mtx);
  73 }
  74
  75 struct frr_pthread *frr_pthread_new(const char *name, unsigned int id,
  76                                     void *(*start_routine)(void *),
  77                                     int (*stop_routine)(void **,
  78                                                         struct frr_pthread *))
  79 {
  80         static struct frr_pthread holder = {0};
  81         struct frr_pthread *fpt = NULL;
  82
  83         pthread_mutex_lock(&pthread_table_mtx);
  84         {
  85                 holder.id = id;
  86
  87                 if (!hash_lookup(pthread_table, &holder)) {
  88                         struct frr_pthread *fpt = XCALLOC(
  89                                 MTYPE_FRR_PTHREAD, sizeof(struct frr_pthread));
  90                         fpt->id = id;
  91                         fpt->master = thread_master_create(name);
  92                         fpt->start_routine = start_routine;
  93                         fpt->stop_routine = stop_routine;
  94                         fpt->name = XSTRDUP(MTYPE_FRR_PTHREAD, name);
  95
  96                         hash_get(pthread_table, fpt, hash_alloc_intern);
  97                 }
  98         }
  99         pthread_mutex_unlock(&pthread_table_mtx);
 100
 101         return fpt;
 102 }
 103
 104 void frr_pthread_destroy(struct frr_pthread *fpt)
 105 {
 106         thread_master_free(fpt->master);
 107         XFREE(MTYPE_FRR_PTHREAD, fpt->name);
 108         XFREE(MTYPE_FRR_PTHREAD, fpt);
 109 }
 110
 111 struct frr_pthread *frr_pthread_get(unsigned int id)
 112 {
 113         static struct frr_pthread holder = {0};
 114         struct frr_pthread *fpt;
 115
 116         pthread_mutex_lock(&pthread_table_mtx);
 117         {
 118                 holder.id = id;
 119                 fpt = hash_lookup(pthread_table, &holder);
 120         }
 121         pthread_mutex_unlock(&pthread_table_mtx);
 122
 123         return fpt;
 124 }
 125
 126 int frr_pthread_run(unsigned int id, const pthread_attr_t *attr, void *arg)
 127 {
 128         struct frr_pthread *fpt = frr_pthread_get(id);
 129         int ret;
 130
 131         if (!fpt)
 132                 return -1;
 133
 134         ret = pthread_create(&fpt->thread, attr, fpt->start_routine, arg);
 135
 136         /* Per pthread_create(3), the contents of fpt->thread are undefined if
 137          * pthread_create() did not succeed. Reset this value to zero. */
 138         if (ret < 0)
 139                 memset(&fpt->thread, 0x00, sizeof(fpt->thread));
 140
 141         return ret;
 142 }
 143
 144 /**
 145  * Calls the stop routine for the frr_pthread and resets any relevant fields.
 146  *
 147  * @param fpt - the frr_pthread to stop
 148  * @param result - pointer to result pointer
 149  * @return the return code from the stop routine
 150  */
 151 static int frr_pthread_stop_actual(struct frr_pthread *fpt, void **result)
 152 {
 153         int ret = (*fpt->stop_routine)(result, fpt);
 154         memset(&fpt->thread, 0x00, sizeof(fpt->thread));
 155         return ret;
 156 }
 157
 158 int frr_pthread_stop(unsigned int id, void **result)
 159 {
 160         struct frr_pthread *fpt = frr_pthread_get(id);
 161         return frr_pthread_stop_actual(fpt, result);
 162 }
 163
 164 /**
 165  * Callback for hash_iterate to stop all frr_pthread's.
 166  */
 167 static void frr_pthread_stop_all_iter(struct hash_backet *hb, void *arg)
 168 {
 169         struct frr_pthread *fpt = hb->data;
 170         frr_pthread_stop_actual(fpt, NULL);
 171 }
 172
 173 void frr_pthread_stop_all()
 174 {
 175         pthread_mutex_lock(&pthread_table_mtx);
 176         {
 177                 hash_iterate(pthread_table, frr_pthread_stop_all_iter, NULL);
 178         }
 179         pthread_mutex_unlock(&pthread_table_mtx);
 180 }
 181
 182 unsigned int frr_pthread_get_id()
 183 {
 184         return next_id++;
 185 }
 186
 187 void frr_pthread_yield(void)
 188 {
 189         (void)sched_yield();
 190 }