X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=sched.c;h=44e66c9b62664eb3add50d9924db6b311ea7e273;hp=fad70132232268a2c9aade01c12b29e68f8987dc;hb=08aa4b386c981292aec04fc35fe37133047fb946;hpb=2290d9be0703d3f83f38c2f100b1b41ec0790bb3;ds=sidebyside diff --git a/sched.c b/sched.c index fad70132..44e66c9b 100644 --- a/sched.c +++ b/sched.c @@ -1,4 +1,16 @@ +/* + * Copyright (C) 2006-2009 Andre Noll + * + * Licensed under the GPL v2. For licencing details see COPYING. + */ + +/** \file sched.c Paraslash's scheduling functions. */ + +#include +#include /* readdir() */ +#include #include + #include "para.h" #include "ipc.h" #include "fd.h" @@ -7,26 +19,52 @@ #include "string.h" #include "error.h" -struct list_head pre_select_list; -struct list_head post_select_list; +static struct list_head pre_select_list, post_select_list; +static int initialized; + +static struct timeval now_struct; +struct timeval *now = &now_struct; + +/** + * Remove a task from the scheduler. + * + * \param t The task to remove. + * + * If the pre_select pointer of \a t is not \p NULL, it is removed from + * the pre_select list of the scheduler. Same goes for \a post_select. + */ +static void unregister_task(struct task *t) +{ + if (!initialized) + return; + PARA_INFO_LOG("unregistering %s (%s)\n", t->status, + t->error <0? para_strerror(-t->error) : "shutdown"); + if (t->pre_select) + list_del(&t->pre_select_node); + if (t->post_select) + list_del(&t->post_select_node); + t->error = -E_TASK_UNREGISTERED; +} + static void sched_preselect(struct sched *s) { struct task *t, *tmp; -again: list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) { - t->pre_select(s, t); - if (t->ret > 0 || !t->error_handler) - continue; - if (t->ret < 0) { - t->error_handler(t); - goto again; - } - if (!(t->flags & PRE_EOF_IS_ERROR)) + if (t->error >= 0 && t->pre_select) + t->pre_select(s, t); +// PARA_INFO_LOG("%s \n", t->status); + if (t->error >= 0) continue; - t->ret = -E_PRE_EOF; - t->error_handler(t); - goto again; + /* + * We have to check whether the list is empty because the call + * to ->pre_select() might have called sched_shutdown(). In + * this case t has been unregistered already, so we must not + * unregister it again. + */ + if (list_empty(&pre_select_list)) + return; + unregister_task(t); } } @@ -35,86 +73,180 @@ static void sched_post_select(struct sched *s) struct task *t, *tmp; list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) { - t->post_select(s, t); - if (t->ret > 0 || !t->error_handler) - continue; - if (t->ret < 0) { - t->error_handler(t); + if (t->error >= 0) + t->post_select(s, t); +// PARA_INFO_LOG("%s: %d\n", t->status, t->ret); + if (t->error >= 0) continue; - } - if (!(t->flags & POST_EOF_IS_ERROR)) - continue; - t->ret = -E_POST_EOF; - t->error_handler(t); + /* nec., see sched_preselect() */ + if (list_empty(&post_select_list)) + return; + unregister_task(t); } } -int sched(struct sched *s) +/** + * The core function for all paraslash programs. + * + * \param s Pointer to the scheduler struct. + * + * This function updates the global \a now pointer, calls all registered + * pre_select hooks which may set the timeout and add any file descriptors to + * the fd sets of \a s. Next, it calls para_select() and makes the result available + * to the registered tasks by calling their post_select hook. + * + * \return Zero if no more tasks are left in either of the two lists, negative + * if para_select returned an error. + * + * \sa task, now. + */ +int schedule(struct sched *s) { + int ret; - gettimeofday(&s->now, NULL); + if (!initialized) + return -E_NOT_INITIALIZED; + if (!s->select_function) + s->select_function = para_select; + gettimeofday(now, NULL); again: FD_ZERO(&s->rfds); FD_ZERO(&s->wfds); s->timeout = s->default_timeout; s->max_fileno = -1; sched_preselect(s); - s->select_ret = para_select(s->max_fileno + 1, &s->rfds, - &s->wfds, &s->timeout); - if (s->select_ret < 0) - return s->select_ret; - gettimeofday(&s->now, NULL); + if (list_empty(&pre_select_list) && list_empty(&post_select_list)) + return 0; + ret = s->select_function(s->max_fileno + 1, &s->rfds, &s->wfds, &s->timeout); + if (ret < 0) + return ret; + gettimeofday(now, NULL); sched_post_select(s); if (list_empty(&pre_select_list) && list_empty(&post_select_list)) return 0; goto again; } -void *register_task(struct task *t) +/** + * Initialize the paraslash scheduler. + */ +static void init_sched(void) { - PARA_INFO_LOG("registering task %p\n", t); + PARA_INFO_LOG("initializing scheduler\n"); + INIT_LIST_HEAD(&pre_select_list); + INIT_LIST_HEAD(&post_select_list); + initialized = 1; +} + +/** + * Add a task to the scheduler. + * + * \param t the task to add + * + * If the pre_select pointer of \a t is not \p NULL, it is added to + * the pre_select list of the scheduler. Same goes for post_select. + * + * \sa task::pre_select, task::post_select + */ +void register_task(struct task *t) +{ + if (!initialized) + init_sched(); + PARA_INFO_LOG("registering %s (%p)\n", t->status, t); if (t->pre_select) { PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select); - if (t->flags & PRE_ADD_TAIL) - list_add_tail(&t->pre_select_node, &pre_select_list); - else - list_add(&t->pre_select_node, &pre_select_list); + list_add_tail(&t->pre_select_node, &pre_select_list); } if (t->post_select) { - PARA_DEBUG_LOG("post_select: %p\n", &t->pre_select); - if (t->flags & POST_ADD_TAIL) - list_add_tail(&t->post_select_node, &post_select_list); - else - list_add(&t->post_select_node, &post_select_list); + PARA_DEBUG_LOG("post_select: %p\n", &t->post_select); + list_add_tail(&t->post_select_node, &post_select_list); } - return t; } -void unregister_task(struct task *t) -{ - PARA_INFO_LOG("unregistering task %p\n", t); - if (t->pre_select) - list_del(&t->pre_select_node); - if (t->post_select) - list_del(&t->post_select_node); -}; - -void init_sched(void) -{ - INIT_LIST_HEAD(&pre_select_list); - INIT_LIST_HEAD(&post_select_list); -}; - +/** + * Unregister all tasks. + * + * This will cause \a schedule() to return immediately because both the + * \a pre_select_list and the \a post_select_list are empty. + */ void sched_shutdown(void) { struct task *t, *tmp; + if (!initialized) + return; list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) unregister_task(t); - /* remove tasks which do not have a pre_select hook */ list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) unregister_task(t); -}; + initialized = 0; +} +/** + * Get the list of all registered tasks. + * + * \return The task list. + * + * Each entry of the list contains an identifier which is simply a hex number + * that may be used in \a kill_task() to terminate the task. + * The result ist dynamically allocated and must be freed by the caller. + */ +char *get_task_list(void) +{ + struct task *t, *tmp; + char *msg = NULL; -//char *get_tast_list(); + if (!initialized) + return NULL; + list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) { + char *tmp_msg; + tmp_msg = make_message("%s%p\tpre\t%s\n", msg? msg : "", t, t->status); + free(msg); + msg = tmp_msg; + } + list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) { + char *tmp_msg; +// if (t->pre_select) +// continue; + tmp_msg = make_message("%s%p\tpost\t%s\n", msg? msg : "", t, t->status); + free(msg); + msg = tmp_msg; + } + //PARA_DEBUG_LOG("task list:\n%s", msg); + return msg; +} + +/** + * Simulate an error for the given task. + * + * \param id The task identifier. + * + * Find the task identified by \a id, set the tasks' error value to + * \p -E_TASK_KILLED and unregister the task. + * + * \return Positive on success, negative on errors (e.g. if \a id does not + * correspond to a registered task). + */ +int kill_task(char *id) +{ + struct task *t, *tmp; + char buf[20]; + + if (!initialized) + return -E_NOT_INITIALIZED; + list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) { + sprintf(buf, "%p", t); + if (strcmp(id, buf)) + continue; + t->error = -E_TASK_KILLED; + return 1; + } + list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) { + sprintf(buf, "%p", t); + if (strcmp(id, buf)) + continue; + t->error = -E_TASK_KILLED; + return 1; + } + return -E_NO_SUCH_TASK; +}