PF_SRV_MSG_EXIT
};
+/**
+* @brief This structure is shared betwee the controlling parent and the
+* the child. The parent can only write to the 'cmds' and
+* 'allowed_clients' variables, while a child is running.
+* The child can change 'status', and 'num_clients'.
+* All other variables are initialized by the parent before forking the
+* child.
+*/
struct pf_worker_data {
pid_t pid;
enum pf_worker_status status;
int allowed_clients;
};
+/**
+* @brief This is the 'main' function called by a child right after the fork.
+* It is daemon specific and should initialize and perform whatever
+* operation the child is meant to do. Returning from this function will
+* cause the termination of the child.
+*
+* @param ev The event context
+* @param pf The mmaped area used to communicate with parent
+* @param listen_fd_size The number of file descriptors to monitor
+* @param listen_fds The array of file descriptors
+* @param lock_fd The locking file descriptor
+* @param private_data Private data that needs to be passed to the main
+* function from the calling parent.
+*
+* @return Returns the exit status to be reported to the parent via exit()
+*/
typedef int (prefork_main_fn_t)(struct tevent_context *ev,
struct pf_worker_data *pf,
int listen_fd_size,
/* ==== Functions used by controlling process ==== */
+/**
+* @brief Creates the first pool of preforked processes
+*
+* @param ev_ctx The event context
+* @param mem_ctx The memory context used to hold the pool structure
+* @param listen_fd_size The number of file descriptors to monitor
+* @param listen_fds The array of file descriptors to monitor
+* @param min_children Minimum number of children that must be available at
+* any given time
+* @param max_children Maximum number of children that can be started. Also
+* determines the initial size of the pool.
+* @param main_fn The children 'main' function to be called after fork
+* @param private_data The children private data.
+* @param pf_pool The allocated pool.
+*
+* @return True if it was successful, False otherwise.
+*/
bool prefork_create_pool(struct tevent_context *ev_ctx, TALLOC_CTX *mem_ctx,
int listen_fd_size, int *listen_fds,
int min_children, int max_children,
prefork_main_fn_t *main_fn, void *private_data,
struct prefork_pool **pf_pool);
+/**
+* @brief Function used to attemp to expand the size of children.
+*
+* @param pfp The pool structure.
+* @param new_max The new max number of children.
+*
+* @return 0 if operation was successful
+* ENOSPC if the mmap area could not be grown to the requested size
+* EINVAL if the new max is invalid.
+*
+* NOTE: this funciton can easily fail if the mmap area cannot be enlarged.
+* A well behaving parent MUST NOT error out if this happen.
+*/
int prefork_expand_pool(struct prefork_pool *pfp, int new_max);
+/**
+* @brief Used to prefork a number of new children
+*
+* @param ev_ctx The event context
+* @param pfp The pool structure
+* @param num_children The number of children to be started
+*
+* @return The number of new children effectively forked.
+*
+* NOTE: This method does not expand the pool, if the max number of children
+* has already been forked it will do nothing.
+*/
int prefork_add_children(struct tevent_context *ev_ctx,
struct prefork_pool *pfp,
int num_children);
+/**
+* @brief Commands a number fo children to stop and exit
+*
+* @param pfp The pool.
+* @param num_children The number of children we need to retire.
+* @param age_limit The minimum age a child has been active to be
+* considered for retirement. (Compared against the
+* 'started' value in the pf_worker_data structure of the
+* children.
+*
+* @return Number of children that were signaled to stop
+*
+* NOTE: Only children that has no attached clients can be stopped.
+* If all the available children are too young or are busy than it
+* is possible that none will be asked to stop.
+*/
int prefork_retire_children(struct prefork_pool *pfp,
int num_children, time_t age_limit);
+/**
+* @brief Count the number of active children
+*
+* @param pfp The pool.
+* @param total Returns the number of children currently alive
+*
+* @return The number of children actually serving clients
+*/
int prefork_count_active_children(struct prefork_pool *pfp, int *total);
+/**
+* @brief Mark a child structure as free, based on the dead child pid.
+* This function is called when the parent gets back notice a child
+* has died through waitpid. It is critical to call this function
+* when children are reaped so that memory slots can be freed.
+*
+* @param pfp The pool.
+* @param pid The child pid.
+*
+* @return True if the slot was clared. False if the pid is not listed.
+*/
bool prefork_mark_pid_dead(struct prefork_pool *pfp, pid_t pid);
+
+/**
+* @brief Inform all children that they are allowed to accept 'max' clients
+* now. Use this when all children are already busy and more clients
+* are trying to connect. It will allow each child to handle more than
+* one client at a time, up to 'max'.
+*
+* @param pfp The pool.
+* @param max Max number of clients per child.
+*/
void prefork_increase_allowed_clients(struct prefork_pool *pfp, int max);
+
+/**
+* @brief Reset the maximum allowd clients per child to 1.
+* Does not reduce the number of clients actually beeing served by
+* any given child, but prevents children from overcommitting from
+* now on.
+*
+* @param pfp The pool.
+*/
void prefork_reset_allowed_clients(struct prefork_pool *pfp);
+
+/**
+* @brief Send a specific signal to all children.
+* Used to send SIGHUP when a reload of the configuration is needed
+* for example.
+*
+* @param pfp The pool.
+* @param signal_num The signal number to be sent.
+*/
void prefork_send_signal_to_all(struct prefork_pool *pfp, int signal_num);
/* ==== Functions used by children ==== */
+/**
+* @brief Try to listen and accept on one of the listening sockets.
+* Asynchronusly tries to grab the lock and perform an accept.
+* Will automatically updated the 'status' of the child and handle
+* all the locking/unlocking/timingout as necessary.
+* Changes behavior depending on whether the child already has other
+* client connections. If not it blocks on the lock call for periods of
+* time. Otherwise it loops on the lock using a timer in order to allow
+* processing of the other clients requests.
+*
+* @param mem_ctx The memory context on whic to allocate the request
+* @param ev The event context
+* @param pf The child/parent shared structure
+* @param listen_fd_size The number of listening file descriptors
+* @param listen_fds The array of listening file descriptors
+* @param lock_fd The locking file descriptor
+* @param addr The structure that will hold the client address on
+* return
+* @param addrlen The structure length on return.
+*
+* @return The tevent request pointer or NULL on allocation errors.
+*/
struct tevent_req *prefork_listen_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct pf_worker_data *pf,
int lock_fd,
struct sockaddr *addr,
socklen_t *addrlen);
+/**
+* @brief Returns the file descriptor after the new client connection has
+* been accepted.
+*
+* @param req The request
+* @param fd The new file descriptor.
+*
+* @return The error in case the operation failed.
+*/
int prefork_listen_recv(struct tevent_req *req, int *fd);
git.samba.org / amitay / samba.git / commitdiff