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Diffstat (limited to '')
| -rw-r--r-- | src/applet.c | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/src/applet.c b/src/applet.c new file mode 100644 index 0000000..c777bc2 --- /dev/null +++ b/src/applet.c @@ -0,0 +1,269 @@ +/* + * Functions managing applets + * + * Copyright 2000-2015 Willy Tarreau <w@1wt.eu> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + */ + +#include <stdio.h> +#include <stdlib.h> + +#include <haproxy/api.h> +#include <haproxy/applet.h> +#include <haproxy/channel.h> +#include <haproxy/list.h> +#include <haproxy/sc_strm.h> +#include <haproxy/stconn.h> +#include <haproxy/stream.h> +#include <haproxy/task.h> + +unsigned int nb_applets = 0; + +DECLARE_POOL(pool_head_appctx, "appctx", sizeof(struct appctx)); + +/* Tries to allocate a new appctx and initialize all of its fields. The appctx + * is returned on success, NULL on failure. The appctx must be released using + * appctx_free(). <applet> is assigned as the applet, but it can be NULL. The + * applet's task is always created on the current thread. + */ +struct appctx *appctx_new(struct applet *applet, struct sedesc *sedesc, unsigned long thread_mask) +{ + struct appctx *appctx; + + /* Backend appctx cannot be started on another thread than the local one */ + BUG_ON(thread_mask != tid_bit && sedesc); + + appctx = pool_zalloc(pool_head_appctx); + if (unlikely(!appctx)) + goto fail_appctx; + + LIST_INIT(&appctx->wait_entry); + appctx->obj_type = OBJ_TYPE_APPCTX; + appctx->applet = applet; + appctx->sess = NULL; + + appctx->t = task_new(thread_mask); + if (unlikely(!appctx->t)) + goto fail_task; + + if (!sedesc) { + sedesc = sedesc_new(); + if (unlikely(!sedesc)) + goto fail_endp; + sedesc->se = appctx; + se_fl_set(sedesc, SE_FL_T_APPLET | SE_FL_ORPHAN); + } + + appctx->sedesc = sedesc; + appctx->t->process = task_run_applet; + appctx->t->context = appctx; + + LIST_INIT(&appctx->buffer_wait.list); + appctx->buffer_wait.target = appctx; + appctx->buffer_wait.wakeup_cb = appctx_buf_available; + + _HA_ATOMIC_INC(&nb_applets); + return appctx; + + fail_endp: + task_destroy(appctx->t); + fail_task: + pool_free(pool_head_appctx, appctx); + fail_appctx: + return NULL; +} + +/* Finalize the frontend appctx startup. It must not be called for a backend + * appctx. This function is responsible to create the appctx's session and the + * frontend stream connector. By transitivity, the stream is also created. + * + * It returns 0 on success and -1 on error. In this case, it is the caller + * responsibility to release the appctx. However, the session is released if it + * was created. On success, if an error is encountered in the caller function, + * the stream must be released instead of the appctx. To be sure, + * appctx_free_on_early_error() must be called in this case. + */ +int appctx_finalize_startup(struct appctx *appctx, struct proxy *px, struct buffer *input) +{ + struct session *sess; + + /* async startup is only possible for frontend appctx. Thus for orphan + * appctx. Because no backend appctx can be orphan. + */ + BUG_ON(!se_fl_test(appctx->sedesc, SE_FL_ORPHAN)); + + sess = session_new(px, NULL, &appctx->obj_type); + if (!sess) + return -1; + if (!sc_new_from_endp(appctx->sedesc, sess, input)) { + session_free(sess); + return -1; + } + appctx->sess = sess; + return 0; +} + +/* Release function to call when an error occurred during init stage of a + * frontend appctx. For a backend appctx, it just calls appctx_free() + */ +void appctx_free_on_early_error(struct appctx *appctx) +{ + /* If a frontend appctx is attached to a stream connector, release the stream + * instead of the appctx. + */ + if (!se_fl_test(appctx->sedesc, SE_FL_ORPHAN) && !(appctx_sc(appctx)->flags & SC_FL_ISBACK)) { + stream_free(appctx_strm(appctx)); + return; + } + appctx_free(appctx); +} + +/* reserves a command context of at least <size> bytes in the <appctx>, for + * use by a CLI command or any regular applet. The pointer to this context is + * stored in ctx.svcctx and is returned. The caller doesn't need to release + * it as it's allocated from reserved space. If the size is larger than + * APPLET_MAX_SVCCTX a crash will occur (hence that will never happen outside + * of development). + * + * Note that the command does *not* initialize the area, so that it can easily + * be used upon each entry in a function. It's left to the initialization code + * to do it if needed. The CLI will always zero the whole area before calling + * a keyword's ->parse() function. + */ +void *applet_reserve_svcctx(struct appctx *appctx, size_t size) +{ + BUG_ON(size > APPLET_MAX_SVCCTX); + appctx->svcctx = &appctx->svc.storage; + return appctx->svcctx; +} + +/* This is used to reset an svcctx and the svc.storage without releasing the + * appctx. In fact this is only used by the CLI applet between commands. + */ +void applet_reset_svcctx(struct appctx *appctx) +{ + memset(&appctx->svc.storage, 0, APPLET_MAX_SVCCTX); + appctx->svcctx = NULL; +} + +/* call the applet's release() function if any, and marks the sedesc as shut. + * Needs to be called upon close(). + */ +void appctx_shut(struct appctx *appctx) +{ + if (se_fl_test(appctx->sedesc, SE_FL_SHR | SE_FL_SHW)) + return; + + if (appctx->applet->release) + appctx->applet->release(appctx); + + se_fl_set(appctx->sedesc, SE_FL_SHRR | SE_FL_SHWN); +} + +/* Callback used to wake up an applet when a buffer is available. The applet + * <appctx> is woken up if an input buffer was requested for the associated + * stream connector. In this case the buffer is immediately allocated and the + * function returns 1. Otherwise it returns 0. Note that this automatically + * covers multiple wake-up attempts by ensuring that the same buffer will not + * be accounted for multiple times. + */ +int appctx_buf_available(void *arg) +{ + struct appctx *appctx = arg; + struct stconn *sc = appctx_sc(appctx); + + /* allocation requested ? */ + if (!(sc->flags & SC_FL_NEED_BUFF)) + return 0; + + sc_have_buff(sc); + + /* was already allocated another way ? if so, don't take this one */ + if (c_size(sc_ic(sc)) || sc_ic(sc)->pipe) + return 0; + + /* allocation possible now ? */ + if (!b_alloc(&sc_ic(sc)->buf)) { + sc_need_buff(sc); + return 0; + } + + task_wakeup(appctx->t, TASK_WOKEN_RES); + return 1; +} + +/* Default applet handler */ +struct task *task_run_applet(struct task *t, void *context, unsigned int state) +{ + struct appctx *app = context; + struct stconn *sc; + unsigned int rate; + size_t count; + + if (app->state & APPLET_WANT_DIE) { + __appctx_free(app); + return NULL; + } + + if (se_fl_test(app->sedesc, SE_FL_ORPHAN)) { + /* Finalize init of orphan appctx. .init callback function must + * be defined and it must finalize appctx startup. + */ + BUG_ON(!app->applet->init); + + if (appctx_init(app) == -1) { + appctx_free_on_early_error(app); + return NULL; + } + BUG_ON(!app->sess || !appctx_sc(app) || !appctx_strm(app)); + } + + sc = appctx_sc(app); + + /* We always pretend the applet can't get and doesn't want to + * put, it's up to it to change this if needed. This ensures + * that one applet which ignores any event will not spin. + */ + applet_need_more_data(app); + applet_have_no_more_data(app); + + /* Now we'll try to allocate the input buffer. We wake up the applet in + * all cases. So this is the applet's responsibility to check if this + * buffer was allocated or not. This leaves a chance for applets to do + * some other processing if needed. The applet doesn't have anything to + * do if it needs the buffer, it will be called again upon readiness. + */ + if (!sc_alloc_ibuf(sc, &app->buffer_wait)) + applet_have_more_data(app); + + count = co_data(sc_oc(sc)); + app->applet->fct(app); + + /* now check if the applet has released some room and forgot to + * notify the other side about it. + */ + if (count != co_data(sc_oc(sc))) { + sc_oc(sc)->flags |= CF_WRITE_PARTIAL | CF_WROTE_DATA; + sc_have_room(sc_opposite(sc)); + } + + /* measure the call rate and check for anomalies when too high */ + if (((b_size(sc_ib(sc)) && sc->flags & SC_FL_NEED_BUFF) || // asks for a buffer which is present + (b_size(sc_ib(sc)) && !b_data(sc_ib(sc)) && sc->flags & SC_FL_NEED_ROOM) || // asks for room in an empty buffer + (b_data(sc_ob(sc)) && sc_is_send_allowed(sc)) || // asks for data already present + (!b_data(sc_ib(sc)) && b_data(sc_ob(sc)) && // didn't return anything ... + (sc_oc(sc)->flags & (CF_WRITE_PARTIAL|CF_SHUTW_NOW)) == CF_SHUTW_NOW))) { // ... and left data pending after a shut + rate = update_freq_ctr(&app->call_rate, 1); + if (rate >= 100000 && app->call_rate.prev_ctr) // looped like this more than 100k times over last second + stream_dump_and_crash(&app->obj_type, read_freq_ctr(&app->call_rate)); + } + + sc->app_ops->wake(sc); + channel_release_buffer(sc_ic(sc), &app->buffer_wait); + return t; +} |