2 This file is part of GNUnet.
3 Copyright (C) 2011, 2012 Christian Grothoff
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6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
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11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
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18 Boston, MA 02110-1301, USA.
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_server_lib.h"
44 * The handle to a helper process.
46 struct GNUNET_HELPER_Handle;
50 * Callback that will be called when the helper process dies. This is not called
51 * when the helper process is stoped using GNUNET_HELPER_stop()
53 * @param cls the closure from GNUNET_HELPER_start()
55 typedef void (*GNUNET_HELPER_ExceptionCallback) (void *cls);
59 * Starts a helper and begins reading from it. The helper process is
60 * restarted when it dies except when it is stopped using GNUNET_HELPER_stop()
61 * or when the exp_cb callback is not NULL.
63 * @param with_control_pipe does the helper support the use of a control pipe for signalling?
64 * @param binary_name name of the binary to run
65 * @param binary_argv NULL-terminated list of arguments to give when starting the binary (this
66 * argument must not be modified by the client for
67 * the lifetime of the helper handle)
68 * @param cb function to call if we get messages from the helper
69 * @param exp_cb the exception callback to call. Set this to NULL if the helper
70 * process has to be restarted automatically when it dies/crashes
71 * @param cb_cls closure for the above callbacks
72 * @return the new Handle, NULL on error
74 struct GNUNET_HELPER_Handle *
75 GNUNET_HELPER_start (int with_control_pipe,
76 const char *binary_name,
77 char *const binary_argv[],
78 GNUNET_SERVER_MessageTokenizerCallback cb,
79 GNUNET_HELPER_ExceptionCallback exp_cb,
84 * Sends termination signal to the helper process. The helper process is not
85 * reaped; call GNUNET_HELPER_wait() for reaping the dead helper process.
87 * @param h the helper handle
88 * @param soft_kill if #GNUNET_YES, signals termination by closing the helper's
89 * stdin; #GNUNET_NO to signal termination by sending SIGTERM to helper
90 * @return #GNUNET_OK on success; #GNUNET_SYSERR on error
93 GNUNET_HELPER_kill (struct GNUNET_HELPER_Handle *h, int soft_kill);
97 * Reap the helper process. This call is blocking (!). The helper process
98 * should either be sent a termination signal before or should be dead before
99 * calling this function
101 * @param h the helper handle
102 * @return #GNUNET_OK on success; #GNUNET_SYSERR on error
105 GNUNET_HELPER_wait (struct GNUNET_HELPER_Handle *h);
109 * Free's the resources occupied by the helper handle
111 * @param h the helper handle to free
114 GNUNET_HELPER_destroy (struct GNUNET_HELPER_Handle *h);
118 * Kills the helper, closes the pipe, frees the handle and calls wait() on the
121 * @param h handle to helper to stop
122 * @param soft_kill if #GNUNET_YES, signals termination by closing the helper's
123 * stdin; #GNUNET_NO to signal termination by sending SIGTERM to helper
126 GNUNET_HELPER_stop (struct GNUNET_HELPER_Handle *h, int soft_kill);
130 * Continuation function.
133 * @param result #GNUNET_OK on success,
134 * #GNUNET_NO if helper process died
135 * #GNUNET_SYSERR during GNUNET_HELPER_destroy
137 typedef void (*GNUNET_HELPER_Continuation)(void *cls,
142 * Handle to cancel 'send'
144 struct GNUNET_HELPER_SendHandle;
148 * Send an message to the helper.
150 * @param h helper to send message to
151 * @param msg message to send
152 * @param can_drop can the message be dropped if there is already one in the queue?
153 * @param cont continuation to run once the message is out (#GNUNET_OK on succees, #GNUNET_NO
154 * if the helper process died, #GNUNET_SYSERR during #GNUNET_HELPER_destroy).
155 * @param cont_cls closure for @a cont
156 * @return NULL if the message was dropped,
157 * otherwise handle to cancel @a cont (actual transmission may
160 struct GNUNET_HELPER_SendHandle *
161 GNUNET_HELPER_send (struct GNUNET_HELPER_Handle *h,
162 const struct GNUNET_MessageHeader *msg,
164 GNUNET_HELPER_Continuation cont,
169 * Cancel a #GNUNET_HELPER_send operation. If possible, transmitting
170 * the message is also aborted, but at least 'cont' won't be called.
172 * @param sh operation to cancel
175 GNUNET_HELPER_send_cancel (struct GNUNET_HELPER_SendHandle *sh);
179 /* end of include guard: GNUNET_HELPER_LIB_H */
181 /** @} */ /* end of group */