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-rw-r--r--dirmngr/workqueue.c214
1 files changed, 214 insertions, 0 deletions
diff --git a/dirmngr/workqueue.c b/dirmngr/workqueue.c
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+/* workqueue.c - Maintain a queue of background tasks
+ * Copyright (C) 2017 Werner Koch
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG 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.
+ *
+ * GnuPG 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 <https://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0+
+ */
+
+#include <config.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "dirmngr.h"
+
+
+/* An object for one item in the workqueue. */
+struct wqitem_s
+{
+ struct wqitem_s *next;
+
+ /* This flag is set if the task requires network access. */
+ unsigned int need_network:1;
+
+ /* The id of the session which created this task. If this is 0 the
+ * task is not associated with a specific session. */
+ unsigned int session_id;
+
+ /* The function to perform the backgrount task. */
+ wqtask_t func;
+
+ /* A string with the string argument for that task. */
+ char args[1];
+};
+typedef struct wqitem_s *wqitem_t;
+
+
+/* The workque is a simple linked list. */
+static wqitem_t workqueue;
+
+
+/* Dump the queue using Assuan status comments. */
+void
+workqueue_dump_queue (ctrl_t ctrl)
+{
+ wqitem_t saved_workqueue;
+ wqitem_t item;
+ unsigned int count;
+
+ /* Temporay detach the entiere workqueue so that other threads don't
+ * get into our way. */
+ saved_workqueue = workqueue;
+ workqueue = NULL;
+
+ for (count=0, item = saved_workqueue; item; item = item->next)
+ count++;
+
+ dirmngr_status_helpf (ctrl, "wq: number of entries: %u", count);
+ for (item = saved_workqueue; item; item = item->next)
+ dirmngr_status_helpf (ctrl, "wq: sess=%u net=%d %s(\"%.100s%s\")",
+ item->session_id, item->need_network,
+ item->func? item->func (NULL, NULL): "nop",
+ item->args, strlen (item->args) > 100? "[...]":"");
+
+ /* Restore then workqueue. Actually we append the saved queue do a
+ * possibly updated workqueue. */
+ if (!(item=workqueue))
+ workqueue = saved_workqueue;
+ else
+ {
+ while (item->next)
+ item = item->next;
+ item->next = saved_workqueue;
+ }
+}
+
+
+/* Append the task (FUNC,ARGS) to the work queue. FUNC shall return
+ * its name when called with (NULL, NULL). */
+gpg_error_t
+workqueue_add_task (wqtask_t func, const char *args, unsigned int session_id,
+ int need_network)
+{
+ wqitem_t item, wi;
+
+ item = xtrycalloc (1, sizeof *item + strlen (args));
+ if (!item)
+ return gpg_error_from_syserror ();
+ strcpy (item->args, args);
+ item->func = func;
+ item->session_id = session_id;
+ item->need_network = !!need_network;
+
+ if (!(wi=workqueue))
+ workqueue = item;
+ else
+ {
+ while (wi->next)
+ wi = wi->next;
+ wi->next = item;
+ }
+ return 0;
+}
+
+
+/* Run the task described by ITEM. ITEM must have been detached from
+ * the workqueue; its ownership is transferred to this fucntion. */
+static void
+run_a_task (ctrl_t ctrl, wqitem_t item)
+{
+ log_assert (!item->next);
+
+ if (opt.verbose)
+ log_info ("session %u: running %s(\"%s%s\")\n",
+ item->session_id,
+ item->func? item->func (NULL, NULL): "nop",
+ item->args, strlen (item->args) > 100? "[...]":"");
+ if (item->func)
+ item->func (ctrl, item->args);
+
+ xfree (item);
+}
+
+
+/* Run tasks not associated with a session. This is called from the
+ * ticker every few minutes. If WITH_NETWORK is not set tasks which
+ * require the network are not run. */
+void
+workqueue_run_global_tasks (ctrl_t ctrl, int with_network)
+{
+ wqitem_t item, prev;
+
+ with_network = !!with_network;
+
+ if (opt.verbose)
+ log_info ("running scheduled tasks%s\n", with_network?" (with network)":"");
+
+ for (;;)
+ {
+ prev = NULL;
+ for (item = workqueue; item; prev = item, item = item->next)
+ if (!item->session_id
+ && (!item->need_network || (item->need_network && with_network)))
+ break;
+ if (!item)
+ break; /* No more tasks to run. */
+
+ /* Detach that item from the workqueue. */
+ if (!prev)
+ workqueue = item->next;
+ else
+ prev->next = item->next;
+ item->next = NULL;
+
+ /* Run the task. */
+ run_a_task (ctrl, item);
+ }
+}
+
+
+/* Run tasks scheduled for running after a session. Those tasks are
+ * identified by the SESSION_ID. */
+void
+workqueue_run_post_session_tasks (unsigned int session_id)
+{
+ struct server_control_s ctrlbuf;
+ ctrl_t ctrl = NULL;
+ wqitem_t item, prev;
+
+ if (!session_id)
+ return;
+
+ for (;;)
+ {
+ prev = NULL;
+ for (item = workqueue; item; prev = item, item = item->next)
+ if (item->session_id == session_id)
+ break;
+ if (!item)
+ break; /* No more tasks for this session. */
+
+ /* Detach that item from the workqueue. */
+ if (!prev)
+ workqueue = item->next;
+ else
+ prev->next = item->next;
+ item->next = NULL;
+
+ /* Create a CTRL object the first time we need it. */
+ if (!ctrl)
+ {
+ memset (&ctrlbuf, 0, sizeof ctrlbuf);
+ ctrl = &ctrlbuf;
+ dirmngr_init_default_ctrl (ctrl);
+ }
+
+ /* Run the task. */
+ run_a_task (ctrl, item);
+ }
+
+ dirmngr_deinit_default_ctrl (ctrl);
+}