diff options
Diffstat (limited to 'lib/frr_pthread.h')
| -rw-r--r-- | lib/frr_pthread.h | 149 |
1 files changed, 102 insertions, 47 deletions
diff --git a/lib/frr_pthread.h b/lib/frr_pthread.h index f6000340a..2cc50196a 100644 --- a/lib/frr_pthread.h +++ b/lib/frr_pthread.h @@ -1,5 +1,5 @@ /* - * Utilities and interfaces for managing POSIX threads + * Utilities and interfaces for managing POSIX threads within FRR. * Copyright (C) 2017 Cumulus Networks * * This program is free software; you can redistribute it and/or modify @@ -21,36 +21,73 @@ #define _FRR_PTHREAD_H #include <pthread.h> +#include "frratomic.h" +#include "memory.h" #include "thread.h" +DECLARE_MTYPE(FRR_PTHREAD); +DECLARE_MTYPE(PTHREAD_PRIM); + +struct frr_pthread; +struct frr_pthread_attr; + +struct frr_pthread_attr { + int id; + void *(*start)(void *); + int (*stop)(struct frr_pthread *, void **); + const char *name; +}; + struct frr_pthread { /* pthread id */ pthread_t thread; - /* frr thread identifier */ - unsigned int id; - /* thread master for this pthread's thread.c event loop */ struct thread_master *master; - /* start routine */ - void *(*start_routine)(void *); - - /* stop routine */ - int (*stop_routine)(void **, struct frr_pthread *); - - /* the (hopefully descriptive) name of this thread */ - char *name; + /* caller-specified data; start & stop funcs, name, id */ + struct frr_pthread_attr attr; + + /* + * Notification mechanism for allowing pthreads to notify their parents + * when they are ready to do work. This mechanism has two associated + * functions: + * + * - frr_pthread_wait_running() + * This function should be called by the spawning thread after + * frr_pthread_run(). It safely waits until the spawned thread + * indicates that is ready to do work by posting to the condition + * variable. + * + * - frr_pthread_notify_running() + * This function should be called by the spawned thread when it is + * ready to do work. It will wake up any threads waiting on the + * previously described condition. + */ + pthread_cond_t *running_cond; + pthread_mutex_t *running_cond_mtx; + _Atomic bool running; + + /* + * Fake thread-specific storage. No constraints on usage. Helpful when + * creating reentrant pthread implementations. Can be used to pass + * argument to pthread entry function. + */ + void *data; }; -/* Initializes this module. +extern struct frr_pthread_attr frr_pthread_attr_default; + +/* + * Initializes this module. * * Must be called before using any of the other functions. */ void frr_pthread_init(void); -/* Uninitializes this module. +/* + * Uninitializes this module. * * Destroys all registered frr_pthread's and internal data structures. * @@ -59,34 +96,23 @@ void frr_pthread_init(void); */ void frr_pthread_finish(void); -/* Creates a new frr_pthread. - * - * If the provided ID is already assigned to an existing frr_pthread, the - * return value will be NULL. - * - * @param name - the name of the thread. Doesn't have to be unique, but it - * probably should be. This value is copied and may be safely free'd upon - * return. - * - * @param id - the integral ID of the thread. MUST be unique. The caller may - * use this id to retrieve the thread. - * - * @param start_routine - start routine for the pthread, will be passed to - * pthread_create (see those docs for details) +/* + * Creates a new frr_pthread with the given attributes. * - * @param stop_routine - stop routine for the pthread, called to terminate the - * thread. This function should gracefully stop the pthread and clean up any - * thread-specific resources. The passed pointer is used to return a data - * result. + * The 'attr' argument should be filled out with the desired attributes, + * including ID, start and stop functions and the desired name. Alternatively, + * if attr is NULL, the default attributes will be used. The pthread will be + * set up to run a basic threadmaster loop and the name will be "Anonymous". + * Scheduling tasks onto the threadmaster in the 'master' field of the returned + * frr_pthread will cause them to run on that pthread. * + * @param attr - the thread attributes * @return the created frr_pthread upon success, or NULL upon failure */ -struct frr_pthread *frr_pthread_new(const char *name, unsigned int id, - void *(*start_routine)(void *), - int (*stop_routine)(void **, - struct frr_pthread *)); +struct frr_pthread *frr_pthread_new(struct frr_pthread_attr *attr); -/* Destroys an frr_pthread. +/* + * Destroys an frr_pthread. * * Assumes that the associated pthread, if any, has already terminated. * @@ -94,38 +120,66 @@ struct frr_pthread *frr_pthread_new(const char *name, unsigned int id, */ void frr_pthread_destroy(struct frr_pthread *fpt); -/* Gets an existing frr_pthread by its id. +/* + * Gets an existing frr_pthread by its id. * * @return frr_thread associated with the provided id, or NULL on error */ struct frr_pthread *frr_pthread_get(unsigned int id); -/* Creates a new pthread and binds it to a frr_pthread. +/* + * Creates a new pthread and binds it to a frr_pthread. * * This function is a wrapper for pthread_create. The first parameter is the * frr_pthread to bind the created pthread to. All subsequent arguments are - * passed unmodified to pthread_create(). + * passed unmodified to pthread_create(). The frr_pthread * provided will be + * used as the argument to the pthread entry function. If it is necessary to + * pass additional data, the 'data' field in the frr_pthread may be used. * * This function returns the same code as pthread_create(). If the value is * zero, the provided frr_pthread is bound to a running POSIX thread. If the * value is less than zero, the provided frr_pthread is guaranteed to be a * clean instance that may be susbsequently passed to frr_pthread_run(). * - * @param id - frr_pthread to bind the created pthread to + * @param fpt - frr_pthread * to run * @param attr - see pthread_create(3) - * @param arg - see pthread_create(3) * * @return see pthread_create(3) */ -int frr_pthread_run(unsigned int id, const pthread_attr_t *attr, void *arg); +int frr_pthread_run(struct frr_pthread *fpt, const pthread_attr_t *attr); -/* Stops an frr_pthread with a result. +/* + * Waits until the specified pthread has finished setting up and is ready to + * begin work. * - * @param id - frr_pthread to stop + * If the pthread's code makes use of the startup synchronization mechanism, + * this function should be called before attempting to use the functionality + * exposed by the pthread. It waits until the 'running' condition is satisfied + * (see struct definition of frr_pthread). + * + * @param fpt - the frr_pthread * to wait on + */ +void frr_pthread_wait_running(struct frr_pthread *fpt); + +/* + * Notifies other pthreads that the calling thread has finished setting up and + * is ready to begin work. + * + * This will allow any other pthreads waiting in 'frr_pthread_wait_running' to + * proceed. + * + * @param fpt - the frr_pthread * that has finished setting up + */ +void frr_pthread_notify_running(struct frr_pthread *fpt); + +/* + * Stops a frr_pthread with a result. + * + * @param fpt - frr_pthread * to stop * @param result - where to store the thread's result, if any. May be NULL if a * result is not needed. */ -int frr_pthread_stop(unsigned int id, void **result); +int frr_pthread_stop(struct frr_pthread *fpt, void **result); /* Stops all frr_pthread's. */ void frr_pthread_stop_all(void); @@ -133,7 +187,8 @@ void frr_pthread_stop_all(void); /* Yields the current thread of execution */ void frr_pthread_yield(void); -/* Returns a unique identifier for use with frr_pthread_new(). +/* + * Returns a unique identifier for use with frr_pthread_new(). * * Internally, this is an integer that increments after each call to this * function. Because the number of pthreads created should never exceed INT_MAX |