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Diffstat (limited to 'include/net-snmp/library/fd_event_manager.h')
| -rw-r--r-- | include/net-snmp/library/fd_event_manager.h | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/include/net-snmp/library/fd_event_manager.h b/include/net-snmp/library/fd_event_manager.h new file mode 100644 index 0000000..ede67b4 --- /dev/null +++ b/include/net-snmp/library/fd_event_manager.h @@ -0,0 +1,134 @@ +/************************************************************************** + * UNIT: File Descriptor (FD) Event Manager + * + * OVERVIEW: This unit contains functions to register a FD with the FD + * event manager for callbacks when activity is received on that + * FD. Notification of read, write, and exception activity can + * all be registered for individually. Once a registered FD is + * closed by the user, the FD must be unregistered. To use + * the FD Event manager you need to make calls to + * netsnmp_external_event_info() and + * netsnmp_dispatch_external_events() in your event loop to receive + * callbacks for registered events. See snmpd.c and snmptrapd.c + * for examples. + * + * LIMITATIONS: + **************************************************************************/ +#ifndef FD_EVENT_MANAGER_H +#define FD_EVENT_MANAGER_H + +#ifdef HAVE_SYS_SELECT_H +#include <sys/select.h> +#endif + +#ifdef __cplusplus +extern "C" { +#endif + +#define NUM_EXTERNAL_FDS 32 +#define FD_REGISTERED_OK 0 +#define FD_REGISTRATION_FAILED -2 +#define FD_UNREGISTERED_OK 0 +#define FD_NO_SUCH_REGISTRATION -1 + +/* Since the inception of netsnmp_external_event_info and + * netsnmp_dispatch_external_events, there is no longer a need for the data + * below to be globally visible. We will leave it global for now for + * compatibility purposes. */ +extern int external_readfd[NUM_EXTERNAL_FDS], external_readfdlen; +extern int external_writefd[NUM_EXTERNAL_FDS], external_writefdlen; +extern int external_exceptfd[NUM_EXTERNAL_FDS], external_exceptfdlen; + +extern void (*external_readfdfunc[NUM_EXTERNAL_FDS]) (int, void *); +extern void (*external_writefdfunc[NUM_EXTERNAL_FDS]) (int, void *); +extern void (*external_exceptfdfunc[NUM_EXTERNAL_FDS]) (int, void *); + +extern void *external_readfd_data[NUM_EXTERNAL_FDS]; +extern void *external_writefd_data[NUM_EXTERNAL_FDS]; +extern void *external_exceptfd_data[NUM_EXTERNAL_FDS]; + +/* Here are the key functions of this unit. Use register_xfd to register + * a callback to be called when there is x activity on the register fd. + * x can be read, write, or except (for exception). When registering, + * you can pass in a pointer to some data that you have allocated that + * you would like to have back when the callback is called. */ +int register_readfd(int, void (*func)(int, void *), void *); +int register_writefd(int, void (*func)(int, void *), void *); +int register_exceptfd(int, void (*func)(int, void *), void *); + +/* Unregisters a given fd for events */ +int unregister_readfd(int); +int unregister_writefd(int); +int unregister_exceptfd(int); + +/* + * External Event Info + * + * Description: + * Call this function to add an external event fds to your read, write, + * exception fds that your application already has. When this function + * returns, your fd_sets will be ready for select(). It returns the + * biggest fd in the fd_sets so far. + * + * Input Parameters: None + * + * Output Parameters: None + * + * In/Out Parameters: + * numfds - The biggest fd so far. On exit to this function, numfds + * could of changed since we pass out the new biggest fd. + * readfds - Set of read FDs that we are monitoring. This function + * can modify this set to have more FDs that we are monitoring. + * writefds - Set of write FDs that we are monitoring. This function + * can modify this set to have more FDs that we are monitoring. + * exceptfds - Set of exception FDs that we are monitoring. This function + * can modify this set to have more FDs that we are monitoring. + * + * Return Value: None + * + * Side Effects: None + */ +NETSNMP_IMPORT +void netsnmp_external_event_info(int *numfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds); + +NETSNMP_IMPORT +void netsnmp_external_event_info2(int *numfds, + netsnmp_large_fd_set *readfds, + netsnmp_large_fd_set *writefds, + netsnmp_large_fd_set *exceptfds); + +/* + * Dispatch External Events + * + * Description: + * Call this function after select returns with pending events. If any of + * them were NETSNMP external events, the registered callback will be called. + * The corresponding fd_set will have the FD cleared after the event is + * dispatched. + * + * Input Parameters: None + * + * Output Parameters: None + * + * In/Out Parameters: + * count - Number of FDs that have activity. In this function, we decrement + * count as we dispatch an event. + * readfds - Set of read FDs that have activity + * writefds - Set of write FDs that have activity + * exceptfds - Set of exception FDs that have activity + * + * Return Value: None + * + * Side Effects: None + */ +NETSNMP_IMPORT +void netsnmp_dispatch_external_events(int *count, fd_set *readfds, fd_set *writefds, fd_set *exceptfds); +NETSNMP_IMPORT +void netsnmp_dispatch_external_events2(int *count, + netsnmp_large_fd_set *readfds, + netsnmp_large_fd_set *writefds, + netsnmp_large_fd_set *exceptfds); +#ifdef __cplusplus +} +#endif +#endif |