1 files changed, 548 insertions, 0 deletions
diff --git a/src/providers/be_ptask.c b/src/providers/be_ptask.c
new file mode 100644
index 0000000..b351a58
--- /dev/null
+++ b/src/providers/be_ptask.c
@@ -0,0 +1,548 @@
+/*
+    Authors:
+        Pavel Březina <pbrezina@redhat.com>
+
+    Copyright (C) 2013 Red Hat
+
+    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 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <tevent.h>
+#include <talloc.h>
+#include <time.h>
+#include <string.h>
+
+#include "util/util.h"
+#include "util/crypto/sss_crypto.h"
+#include "providers/backend.h"
+#include "providers/be_ptask_private.h"
+#include "providers/be_ptask.h"
+
+#define backoff_allowed(ptask) (ptask->max_backoff != 0)
+
+enum be_ptask_delay {
+    BE_PTASK_FIRST_DELAY,
+    BE_PTASK_ENABLED_DELAY,
+    BE_PTASK_PERIOD
+};
+
+static void be_ptask_schedule(struct be_ptask *task,
+                              enum be_ptask_delay delay_type,
+                              uint32_t from);
+
+static int be_ptask_destructor(void *pvt)
+{
+    struct be_ptask *task;
+
+    task = talloc_get_type(pvt, struct be_ptask);
+    if (task == NULL) {
+        DEBUG(SSSDBG_FATAL_FAILURE, "BUG: task is NULL\n");
+        return 0;
+    }
+
+    DEBUG(SSSDBG_TRACE_FUNC, "Terminating periodic task [%s]\n", task->name);
+
+    return 0;
+}
+
+static void be_ptask_online_cb(void *pvt)
+{
+    struct be_ptask *task = NULL;
+
+    task = talloc_get_type(pvt, struct be_ptask);
+    if (task == NULL) {
+        DEBUG(SSSDBG_FATAL_FAILURE, "BUG: task is NULL\n");
+        return;
+    }
+
+    DEBUG(SSSDBG_TRACE_FUNC, "Back end is online\n");
+    be_ptask_enable(task);
+}
+
+static void be_ptask_offline_cb(void *pvt)
+{
+    struct be_ptask *task = NULL;
+    task = talloc_get_type(pvt, struct be_ptask);
+
+    DEBUG(SSSDBG_TRACE_FUNC, "Back end is offline\n");
+    be_ptask_disable(task);
+}
+
+static void be_ptask_timeout(struct tevent_context *ev,
+                             struct tevent_timer *tt,
+                             struct timeval tv,
+                             void *pvt)
+{
+    struct be_ptask *task = NULL;
+    task = talloc_get_type(pvt, struct be_ptask);
+
+    DEBUG(SSSDBG_OP_FAILURE, "Task [%s]: timed out\n", task->name);
+
+    talloc_zfree(task->req);
+    be_ptask_schedule(task, BE_PTASK_PERIOD, BE_PTASK_SCHEDULE_FROM_NOW);
+}
+
+static void be_ptask_done(struct tevent_req *req);
+
+static void be_ptask_execute(struct tevent_context *ev,
+                             struct tevent_timer *tt,
+                             struct timeval tv,
+                             void *pvt)
+{
+    struct be_ptask *task = NULL;
+    struct tevent_timer *timeout = NULL;
+
+    task = talloc_get_type(pvt, struct be_ptask);
+    task->timer = NULL; /* timer is freed by tevent */
+
+    if (be_is_offline(task->be_ctx)) {
+        DEBUG(SSSDBG_TRACE_FUNC, "Back end is offline\n");
+        if (task->flags & BE_PTASK_OFFLINE_SKIP) {
+            be_ptask_schedule(task, BE_PTASK_PERIOD,
+                              BE_PTASK_SCHEDULE_FROM_NOW);
+            return;
+        }
+        else if(task->flags & BE_PTASK_OFFLINE_DISABLE) {
+            /* This case is normally handled by offline callback but we
+             * should handle it here as well since we can get here in some
+             * special cases for example unit tests or tevent events order. */
+            be_ptask_disable(task);
+            return;
+        }
+        /* BE_PTASK_OFFLINE_EXECUTE */
+        /* continue */
+    }
+
+    DEBUG(SSSDBG_TRACE_FUNC, "Task [%s]: executing task, timeout %lu "
+                              "seconds\n", task->name, task->timeout);
+
+    task->last_execution = tv.tv_sec;
+
+    task->req = task->send_fn(task, task->ev, task->be_ctx, task, task->pvt);
+    if (task->req == NULL) {
+        /* skip this iteration and try again later */
+        DEBUG(SSSDBG_OP_FAILURE, "Task [%s]: failed to execute task, "
+              "will try again later\n", task->name);
+
+        be_ptask_schedule(task, BE_PTASK_PERIOD, BE_PTASK_SCHEDULE_FROM_NOW);
+        return;
+    }
+
+    tevent_req_set_callback(task->req, be_ptask_done, task);
+
+    /* schedule timeout */
+    if (task->timeout > 0) {
+        tv = sss_tevent_timeval_current_ofs_time_t(task->timeout);
+        timeout = tevent_add_timer(task->ev, task->req, tv,
+                                   be_ptask_timeout, task);
+        if (timeout == NULL) {
+            /* If we can't guarantee a timeout,
+             * we need to cancel the request. */
+            talloc_zfree(task->req);
+
+            DEBUG(SSSDBG_OP_FAILURE, "Task [%s]: failed to set timeout, "
+                  "the task will be rescheduled\n", task->name);
+
+            be_ptask_schedule(task, BE_PTASK_PERIOD,
+                              BE_PTASK_SCHEDULE_FROM_NOW);
+        }
+    }
+
+    return;
+}
+
+static void be_ptask_done(struct tevent_req *req)
+{
+    struct be_ptask *task = NULL;
+    errno_t ret;
+
+    task = tevent_req_callback_data(req, struct be_ptask);
+
+    ret = task->recv_fn(req);
+    talloc_zfree(req);
+    task->req = NULL;
+    switch (ret) {
+    case EOK:
+        DEBUG(SSSDBG_TRACE_FUNC, "Task [%s]: finished successfully\n",
+                                  task->name);
+
+        be_ptask_schedule(task, BE_PTASK_PERIOD, task->flags);
+        break;
+    default:
+        DEBUG(SSSDBG_OP_FAILURE, "Task [%s]: failed with [%d]: %s\n",
+                                  task->name, ret, sss_strerror(ret));
+
+        be_ptask_schedule(task, BE_PTASK_PERIOD, BE_PTASK_SCHEDULE_FROM_NOW);
+        break;
+    }
+}
+
+static void be_ptask_schedule(struct be_ptask *task,
+                              enum be_ptask_delay delay_type,
+                              uint32_t from)
+{
+    struct timeval tv = { 0, };
+    time_t delay = 0;
+
+    if (!task->enabled) {
+        DEBUG(SSSDBG_TRACE_FUNC, "Task [%s]: disabled\n", task->name);
+        return;
+    }
+
+    switch (delay_type) {
+    case BE_PTASK_FIRST_DELAY:
+        delay = task->first_delay;
+        break;
+    case BE_PTASK_ENABLED_DELAY:
+        delay = task->enabled_delay;
+        break;
+    case BE_PTASK_PERIOD:
+        if (task->flags & BE_PTASK_NO_PERIODIC) {
+            /* Periodic task is disabled, */
+            /* only online/offline change can cause some activity. */
+            return;
+        }
+
+        if (backoff_allowed(task)) {
+            /* double the period for the next execution */
+            task->period = MIN(task->period * 2, task->max_backoff);
+        }
+
+        delay = task->period;
+        break;
+    }
+
+    /* add random offset */
+    if (task->random_offset != 0) {
+        delay = delay + (sss_rand() % task->random_offset);
+    }
+
+    if(from & BE_PTASK_SCHEDULE_FROM_NOW) {
+        tv = sss_tevent_timeval_current_ofs_time_t(delay);
+
+        DEBUG(SSSDBG_TRACE_FUNC, "Task [%s]: scheduling task %lu seconds "
+              "from now [%lu]\n", task->name, delay, tv.tv_sec);
+    }
+    else if (from & BE_PTASK_SCHEDULE_FROM_LAST) {
+        tv = tevent_timeval_set(task->last_execution + delay, 0);
+
+        DEBUG(SSSDBG_TRACE_FUNC, "Task [%s]: scheduling task %lu seconds "
+                                  "from last execution time [%lu]\n",
+                                  task->name, delay, tv.tv_sec);
+    }
+
+    if (task->timer != NULL) {
+        DEBUG(SSSDBG_MINOR_FAILURE, "Task [%s]: another timer is already "
+                                     "active?\n", task->name);
+        talloc_zfree(task->timer);
+    }
+
+    task->timer = tevent_add_timer(task->ev, task, tv, be_ptask_execute, task);
+    if (task->timer == NULL) {
+        /* nothing we can do about it */
+        DEBUG(SSSDBG_CRIT_FAILURE, "Unable to schedule task [%s]\n",
+                                    task->name);
+        be_ptask_disable(task);
+    }
+
+    task->next_execution = tv.tv_sec;
+}
+
+static unsigned int be_ptask_flag_bits(uint32_t flags)
+{
+    unsigned int cnt = 0;
+    while (flags != 0) {
+        cnt += flags & 1;
+        flags >>= 1;
+    }
+    return cnt;
+}
+
+static int be_ptask_flag_check(uint32_t flags)
+{
+    uint32_t tmpflags;
+
+    tmpflags = flags & (BE_PTASK_SCHEDULE_FROM_LAST |
+                        BE_PTASK_SCHEDULE_FROM_NOW);
+    if (be_ptask_flag_bits(tmpflags) != 1) {
+        return EINVAL;
+    }
+
+    tmpflags = flags & (BE_PTASK_OFFLINE_SKIP |
+                        BE_PTASK_OFFLINE_DISABLE |
+                        BE_PTASK_OFFLINE_EXECUTE);
+    if (be_ptask_flag_bits(tmpflags) != 1) {
+        return EINVAL;
+    }
+
+    return EOK;
+}
+
+errno_t be_ptask_create(TALLOC_CTX *mem_ctx,
+                        struct be_ctx *be_ctx,
+                        time_t period,
+                        time_t first_delay,
+                        time_t enabled_delay,
+                        time_t random_offset,
+                        time_t timeout,
+                        time_t max_backoff,
+                        be_ptask_send_t send_fn,
+                        be_ptask_recv_t recv_fn,
+                        void *pvt,
+                        const char *name,
+                        uint32_t flags,
+                        struct be_ptask **_task)
+{
+    struct be_ptask *task = NULL;
+    errno_t ret;
+
+    if (be_ctx == NULL || send_fn == NULL || recv_fn == NULL
+        || name == NULL) {
+        return EINVAL;
+    }
+
+    if (period == 0 && (flags & BE_PTASK_NO_PERIODIC) == 0) {
+        return EINVAL;
+    }
+
+    /* check flags, some of them are exclusive, some must be present */
+    ret = be_ptask_flag_check(flags);
+    if (ret != EOK) {
+        return ret;
+    }
+
+    task = talloc_zero(mem_ctx, struct be_ptask);
+    if (task == NULL) {
+        ret = ENOMEM;
+        goto done;
+    }
+
+    task->ev = be_ctx->ev;
+    task->be_ctx = be_ctx;
+    task->period = period;
+    task->orig_period = period;
+    task->first_delay = first_delay;
+    task->enabled_delay = enabled_delay;
+    task->random_offset = random_offset;
+    task->max_backoff = max_backoff;
+    task->timeout = timeout;
+    task->send_fn = send_fn;
+    task->recv_fn = recv_fn;
+    task->pvt = pvt;
+    task->name = talloc_strdup(task, name);
+    if (task->name == NULL) {
+        ret = ENOMEM;
+        goto done;
+    }
+
+    task->flags = flags;
+    task->enabled = true;
+
+    talloc_set_destructor((TALLOC_CTX*)task, be_ptask_destructor);
+
+    if (flags & BE_PTASK_OFFLINE_DISABLE) {
+        /* install offline and online callbacks */
+        ret = be_add_online_cb(task, be_ctx, be_ptask_online_cb, task, NULL);
+        if (ret != EOK) {
+            DEBUG(SSSDBG_OP_FAILURE,
+                  "Unable to install online callback [%d]: %s\n",
+                  ret, sss_strerror(ret));
+            goto done;
+        }
+
+        ret = be_add_offline_cb(task, be_ctx, be_ptask_offline_cb, task, NULL);
+        if (ret != EOK) {
+            DEBUG(SSSDBG_OP_FAILURE,
+                  "Unable to install offline callback [%d]: %s\n",
+                  ret, sss_strerror(ret));
+            goto done;
+        }
+    }
+
+    DEBUG(SSSDBG_TRACE_FUNC, "Periodic task [%s] was created\n", task->name);
+
+    be_ptask_schedule(task, BE_PTASK_FIRST_DELAY, BE_PTASK_SCHEDULE_FROM_NOW);
+
+    if (_task != NULL) {
+        *_task = task;
+    }
+
+    ret = EOK;
+
+done:
+    if (ret != EOK) {
+        talloc_free(task);
+    }
+
+    return ret;
+}
+
+void be_ptask_enable(struct be_ptask *task)
+{
+    if (task != NULL) {
+        if (task->enabled) {
+            DEBUG(SSSDBG_MINOR_FAILURE, "Task [%s]: already enabled\n",
+                                         task->name);
+            return;
+        }
+
+        DEBUG(SSSDBG_TRACE_FUNC, "Task [%s]: enabling task\n", task->name);
+
+        task->enabled = true;
+        be_ptask_schedule(task, BE_PTASK_ENABLED_DELAY,
+                          BE_PTASK_SCHEDULE_FROM_NOW);
+    }
+}
+
+/* Disable the task, but if a request already in progress, let it finish. */
+void be_ptask_disable(struct be_ptask *task)
+{
+    if (task != NULL) {
+        DEBUG(SSSDBG_TRACE_FUNC, "Task [%s]: disabling task\n", task->name);
+
+        talloc_zfree(task->timer);
+        task->enabled = false;
+        task->period = task->orig_period;
+    }
+}
+
+/* Cancel current timer and schedule new one. */
+void be_ptask_postpone(struct be_ptask *task)
+{
+    if (task == NULL) {
+        return;
+    }
+
+    DEBUG(SSSDBG_TRACE_FUNC, "Task [%s]: rescheduling task\n", task->name);
+    talloc_zfree(task->timer);
+    talloc_zfree(task->req);
+    task->period = task->orig_period;
+
+    be_ptask_schedule(task, BE_PTASK_PERIOD, BE_PTASK_SCHEDULE_FROM_NOW);
+}
+
+void be_ptask_destroy(struct be_ptask **task)
+{
+    talloc_zfree(*task);
+}
+
+time_t be_ptask_get_period(struct be_ptask *task)
+{
+    return task->period;
+}
+
+time_t be_ptask_get_timeout(struct be_ptask *task)
+{
+    return task->timeout;
+}
+
+bool be_ptask_running(struct be_ptask *task)
+{
+    return task->req != NULL;
+}
+
+struct be_ptask_sync_ctx {
+    be_ptask_sync_t fn;
+    void *pvt;
+};
+
+struct be_ptask_sync_state {
+    int dummy;
+};
+
+/* This is not an asynchronous request so there is not any _done function. */
+static struct tevent_req *
+be_ptask_sync_send(TALLOC_CTX *mem_ctx,
+                   struct tevent_context *ev,
+                   struct be_ctx *be_ctx,
+                   struct be_ptask *be_ptask,
+                   void *pvt)
+{
+    struct be_ptask_sync_ctx *ctx = NULL;
+    struct be_ptask_sync_state *state = NULL;
+    struct tevent_req *req = NULL;
+    errno_t ret;
+
+    req = tevent_req_create(mem_ctx, &state, struct be_ptask_sync_state);
+    if (req == NULL) {
+        DEBUG(SSSDBG_CRIT_FAILURE, "tevent_req_create() failed\n");
+        return NULL;
+    }
+
+    ctx = talloc_get_type(pvt, struct be_ptask_sync_ctx);
+    ret = ctx->fn(mem_ctx, ev, be_ctx, be_ptask, ctx->pvt);
+
+    if (ret == EOK) {
+        tevent_req_done(req);
+    } else {
+        tevent_req_error(req, ret);
+    }
+    tevent_req_post(req, ev);
+
+    return req;
+}
+
+static errno_t be_ptask_sync_recv(struct tevent_req *req)
+{
+    TEVENT_REQ_RETURN_ON_ERROR(req);
+
+    return EOK;
+}
+
+errno_t be_ptask_create_sync(TALLOC_CTX *mem_ctx,
+                             struct be_ctx *be_ctx,
+                             time_t period,
+                             time_t first_delay,
+                             time_t enabled_delay,
+                             time_t random_offset,
+                             time_t timeout,
+                             time_t max_backoff,
+                             be_ptask_sync_t fn,
+                             void *pvt,
+                             const char *name,
+                             uint32_t flags,
+                             struct be_ptask **_task)
+{
+    errno_t ret;
+    struct be_ptask_sync_ctx *ctx = NULL;
+
+    ctx = talloc_zero(mem_ctx, struct be_ptask_sync_ctx);
+    if (ctx == NULL) {
+        ret = ENOMEM;
+        goto done;
+    }
+
+    ctx->fn = fn;
+    ctx->pvt = pvt;
+
+    ret = be_ptask_create(mem_ctx, be_ctx, period, first_delay,
+                          enabled_delay, random_offset, timeout,
+                          max_backoff, be_ptask_sync_send, be_ptask_sync_recv,
+                          ctx, name, flags | BE_PTASK_SCHEDULE_FROM_LAST,
+                          _task);
+    if (ret != EOK) {
+        goto done;
+    }
+
+    talloc_steal(*_task, ctx);
+
+    ret = EOK;
+
+done:
+    if (ret != EOK) {
+        talloc_free(ctx);
+    }
+
+    return ret;
+}