2 Unix SMB/CIFS implementation.
5 Copyright (C) Simo Sorce <idra@samba.org> 2011
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #include "system/network.h"
23 #include "lib/tsocket/tsocket.h"
27 enum pf_worker_status {
40 * @brief This structure is shared between the controlling parent and the
41 * the child. The parent can only write to the 'cmds' and
42 * 'allowed_clients' variables, while a child is running.
43 * The child can change 'status', and 'num_clients'.
44 * All other variables are initialized by the parent before forking the
47 struct pf_worker_data {
49 enum pf_worker_status status;
54 enum pf_server_cmds cmds;
59 * @brief This is the 'main' function called by a child right after the fork.
60 * It is daemon specific and should initialize and perform whatever
61 * operation the child is meant to do. Returning from this function will
62 * cause the termination of the child.
64 * @param ev The event context
65 * @param msg_ctx The messaging context
66 * @param pf The mmaped area used to communicate with parent
67 * @param listen_fd_size The number of file descriptors to monitor
68 * @param listen_fds The array of file descriptors
69 * @param private_data Private data that needs to be passed to the main
70 * function from the calling parent.
72 * @return Returns the exit status to be reported to the parent via exit()
74 typedef int (prefork_main_fn_t)(struct tevent_context *ev,
75 struct messaging_context *msg_ctx,
76 struct pf_worker_data *pf,
83 * @brief Callback function for parents that also want to be called on sigchld
85 * @param ev_ctx The event context
86 * @param pool The pool handler
87 * @param private_data Data private to the parent
89 typedef void (prefork_sigchld_fn_t)(struct tevent_context *ev_ctx,
90 struct prefork_pool *pool,
93 /* ==== Functions used by controlling process ==== */
96 * @brief Creates the first pool of preforked processes
98 * @param mem_ctx The memory context used to hold the pool structure
99 * @param ev_ctx The event context
100 * @param msg_ctx The messaging context
101 * @param listen_fd_size The number of file descriptors to monitor
102 * @param listen_fds The array of file descriptors to monitor
103 * @param min_children Minimum number of children that must be available at
105 * @param max_children Maximum number of children that can be started. Also
106 * determines the initial size of the pool.
107 * @param main_fn The children 'main' function to be called after fork
108 * @param private_data The children private data.
109 * @param pf_pool The allocated pool.
111 * @return True if it was successful, False otherwise.
113 bool prefork_create_pool(TALLOC_CTX *mem_ctx,
114 struct tevent_context *ev_ctx,
115 struct messaging_context *msg_ctx,
116 int listen_fd_size, int *listen_fds,
117 int min_children, int max_children,
118 prefork_main_fn_t *main_fn, void *private_data,
119 struct prefork_pool **pf_pool);
121 * @brief Function used to attempt to expand the size of children.
123 * @param pfp The pool structure.
124 * @param new_max The new max number of children.
126 * @return 0 if operation was successful
127 * ENOSPC if the mmap area could not be grown to the requested size
128 * EINVAL if the new max is invalid.
130 * NOTE: this function can easily fail if the mmap area cannot be enlarged.
131 * A well behaving parent MUST NOT error out if this happen.
133 int prefork_expand_pool(struct prefork_pool *pfp, int new_max);
136 * @brief Used to prefork a number of new children
138 * @param ev_ctx The event context
139 * @param msg_ctx The messaging context
140 * @param pfp The pool structure
141 * @param num_children The number of children to be started
143 * @return The number of new children effectively forked.
145 * NOTE: This method does not expand the pool, if the max number of children
146 * has already been forked it will do nothing.
148 int prefork_add_children(struct tevent_context *ev_ctx,
149 struct messaging_context *msg_ctx,
150 struct prefork_pool *pfp,
153 * @brief Commands a number of children to stop and exit
155 * @param pfp The pool.
156 * @param num_children The number of children we need to retire.
157 * @param age_limit The minimum age a child has been active to be
158 * considered for retirement. (Compared against the
159 * 'started' value in the pf_worker_data structure of the
162 * @return Number of children that were signaled to stop
164 * NOTE: Only children that have no attached clients can be stopped.
165 * If all the available children are too young or are busy then it
166 * is possible that none will be asked to stop.
168 int prefork_retire_children(struct prefork_pool *pfp,
169 int num_children, time_t age_limit);
171 * @brief Count the number of children
173 * @param pfp The pool.
174 * @param active Number of children currently active if not NULL
176 * @return The total number of children.
178 int prefork_count_children(struct prefork_pool *pfp, int *active);
181 * @brief Count the number of actual connections currently allowed
183 * @param pfp The pool.
185 * @return The number of connections that can still be opened by clients
186 * with the current pool of children.
188 int prefork_count_allowed_connections(struct prefork_pool *pfp);
191 * @brief Increase the amount of clients each child is allowed to handle
192 * simultaneaously. It will allow each child to handle more than
193 * one client at a time, up to 'max' (currently set to 100).
195 * @param pfp The pool.
196 * @param max Max number of allowed connections per child
198 void prefork_increase_allowed_clients(struct prefork_pool *pfp, int max);
201 * @brief Decrease the amount of clients each child is allowed to handle.
204 * @param pfp The pool.
206 void prefork_decrease_allowed_clients(struct prefork_pool *pfp);
209 * @brief Reset the maximum allowd clients per child to 1.
210 * Does not reduce the number of clients actually beeing served by
211 * any given child, but prevents children from overcommitting from
214 * @param pfp The pool.
216 void prefork_reset_allowed_clients(struct prefork_pool *pfp);
219 * @brief Send a specific signal to all children.
220 * Used to send SIGHUP when a reload of the configuration is needed
223 * @param pfp The pool.
224 * @param signal_num The signal number to be sent.
226 void prefork_send_signal_to_all(struct prefork_pool *pfp, int signal_num);
229 * @brief Sets the SIGCHLD callback
231 * @param pfp The pool handler.
232 * @param sigchld_fn The callback function (pass NULL to unset).
233 * @param private_data Private data for the callback function.
235 void prefork_set_sigchld_callback(struct prefork_pool *pfp,
236 prefork_sigchld_fn_t *sigchld_fn,
239 /* ==== Functions used by children ==== */
242 * @brief Try to listen and accept on one of the listening sockets.
243 * Asynchronusly tries to grab the lock and perform an accept.
244 * Will automatically update the 'status' of the child and handle
245 * all the locking/unlocking/timingout as necessary.
246 * Changes behavior depending on whether the child already has other
247 * client connections. If not it blocks on the lock call for periods of
248 * time. Otherwise it loops on the lock using a timer in order to allow
249 * processing of the other clients requests.
251 * @param mem_ctx The memory context on whic to allocate the request
252 * @param ev The event context
253 * @param pf The child/parent shared structure
254 * @param listen_fd_size The number of listening file descriptors
255 * @param listen_fds The array of listening file descriptors
257 * @return The tevent request pointer or NULL on allocation errors.
259 struct tevent_req *prefork_listen_send(TALLOC_CTX *mem_ctx,
260 struct tevent_context *ev,
261 struct pf_worker_data *pf,
265 * @brief Returns the file descriptor after the new client connection has
268 * @param req The request
269 * @param mem_ctx The memory context for cli_addr and srv_addr
270 * @param fd The new file descriptor.
271 * @param srv_addr The server address in tsocket_address format
272 * @param cli_addr The client address in tsocket_address format
274 * @return The error in case the operation failed.
276 int prefork_listen_recv(struct tevent_req *req,
277 TALLOC_CTX *mem_ctx, int *fd,
278 struct tsocket_address **srv_addr,
279 struct tsocket_address **cli_addr);