2 This file is part of GNUnet.
3 Copyright (C) 2011, 2012 Christian Grothoff
5 GNUnet is free software: you can redistribute it and/or modify it
6 under the terms of the GNU Affero General Public License as published
7 by the Free Software Foundation, either version 3 of the License,
8 or (at your option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Affero General Public License for more details.
15 You should have received a copy of the GNU Affero General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
18 SPDX-License-Identifier: AGPL3.0-or-later
22 * @author Philipp Toelke
23 * @author Christian Grothoff
26 * API for dealing with SUID helper processes
28 * @defgroup helper Helper library
29 * Dealing with SUID helper processes.
31 * Provides an API for dealing with (SUID) helper processes
32 * that communicate via GNUNET_MessageHeaders on STDIN/STDOUT.
37 #ifndef GNUNET_HELPER_LIB_H
38 #define GNUNET_HELPER_LIB_H
40 #include "gnunet_scheduler_lib.h"
41 #include "gnunet_mst_lib.h"
45 * The handle to a helper process.
47 struct GNUNET_HELPER_Handle;
51 * Callback that will be called when the helper process dies. This is not called
52 * when the helper process is stoped using GNUNET_HELPER_stop()
54 * @param cls the closure from GNUNET_HELPER_start()
57 (*GNUNET_HELPER_ExceptionCallback) (void *cls);
61 * Starts a helper and begins reading from it. The helper process is
62 * restarted when it dies except when it is stopped using GNUNET_HELPER_stop()
63 * or when the exp_cb callback is not NULL.
65 * @param with_control_pipe does the helper support the use of a control pipe for signalling?
66 * @param binary_name name of the binary to run
67 * @param binary_argv NULL-terminated list of arguments to give when starting the binary (this
68 * argument must not be modified by the client for
69 * the lifetime of the helper handle)
70 * @param cb function to call if we get messages from the helper
71 * @param exp_cb the exception callback to call. Set this to NULL if the helper
72 * process has to be restarted automatically when it dies/crashes
73 * @param cb_cls closure for the above callbacks
74 * @return the new Handle, NULL on error
76 struct GNUNET_HELPER_Handle *
77 GNUNET_HELPER_start (int with_control_pipe,
78 const char *binary_name,
79 char *const binary_argv[],
80 GNUNET_MessageTokenizerCallback cb,
81 GNUNET_HELPER_ExceptionCallback exp_cb,
86 * Sends termination signal to the helper process. The helper process is not
87 * reaped; call GNUNET_HELPER_wait() for reaping the dead helper process.
89 * @param h the helper handle
90 * @param soft_kill if #GNUNET_YES, signals termination by closing the helper's
91 * stdin; #GNUNET_NO to signal termination by sending SIGTERM to helper
92 * @return #GNUNET_OK on success; #GNUNET_SYSERR on error
95 GNUNET_HELPER_kill (struct GNUNET_HELPER_Handle *h, int soft_kill);
99 * Reap the helper process. This call is blocking (!). The helper process
100 * should either be sent a termination signal before or should be dead before
101 * calling this function
103 * @param h the helper handle
104 * @return #GNUNET_OK on success; #GNUNET_SYSERR on error
107 GNUNET_HELPER_wait (struct GNUNET_HELPER_Handle *h);
111 * Free's the resources occupied by the helper handle
113 * @param h the helper handle to free
116 GNUNET_HELPER_destroy (struct GNUNET_HELPER_Handle *h);
120 * Kills the helper, closes the pipe, frees the handle and calls wait() on the
123 * @param h handle to helper to stop
124 * @param soft_kill if #GNUNET_YES, signals termination by closing the helper's
125 * stdin; #GNUNET_NO to signal termination by sending SIGTERM to helper
128 GNUNET_HELPER_stop (struct GNUNET_HELPER_Handle *h, int soft_kill);
132 * Continuation function.
135 * @param result #GNUNET_OK on success,
136 * #GNUNET_NO if helper process died
137 * #GNUNET_SYSERR during GNUNET_HELPER_destroy
139 typedef void (*GNUNET_HELPER_Continuation)(void *cls,
144 * Handle to cancel 'send'
146 struct GNUNET_HELPER_SendHandle;
150 * Send an message to the helper.
152 * @param h helper to send message to
153 * @param msg message to send
154 * @param can_drop can the message be dropped if there is already one in the queue?
155 * @param cont continuation to run once the message is out (#GNUNET_OK on succees, #GNUNET_NO
156 * if the helper process died, #GNUNET_SYSERR during #GNUNET_HELPER_destroy).
157 * @param cont_cls closure for @a cont
158 * @return NULL if the message was dropped,
159 * otherwise handle to cancel @a cont (actual transmission may
162 struct GNUNET_HELPER_SendHandle *
163 GNUNET_HELPER_send (struct GNUNET_HELPER_Handle *h,
164 const struct GNUNET_MessageHeader *msg,
166 GNUNET_HELPER_Continuation cont,
171 * Cancel a #GNUNET_HELPER_send operation. If possible, transmitting
172 * the message is also aborted, but at least 'cont' won't be called.
174 * @param sh operation to cancel
177 GNUNET_HELPER_send_cancel (struct GNUNET_HELPER_SendHandle *sh);
181 /* end of include guard: GNUNET_HELPER_LIB_H */
183 /** @} */ /* end of group */