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ap_mpm.h
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4  * The ASF licenses this file to You under the Apache License, Version 2.0
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13  * See the License for the specific language governing permissions and
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15  */
16 
26 #ifndef AP_MPM_H
27 #define AP_MPM_H
28 
29 #include "apr_thread_proc.h"
30 #include "httpd.h"
31 #include "scoreboard.h"
32 
33 #ifdef __cplusplus
34 extern "C" {
35 #endif
36 
37 /*
38  The MPM, "multi-processing model" provides an abstraction of the
39  interface with the OS for distributing incoming connections to
40  threads/process for processing. http_main invokes the MPM, and
41  the MPM runs until a shutdown/restart has been indicated.
42  The MPM calls out to the apache core via the ap_process_connection
43  function when a connection arrives.
44 
45  The MPM may or may not be multithreaded. In the event that it is
46  multithreaded, at any instant it guarantees a 1:1 mapping of threads
47  ap_process_connection invocations.
48 
49  Note: In the future it will be possible for ap_process_connection
50  to return to the MPM prior to finishing the entire connection; and
51  the MPM will proceed with asynchronous handling for the connection;
52  in the future the MPM may call ap_process_connection again -- but
53  does not guarantee it will occur on the same thread as the first call.
54 
55  The MPM further guarantees that no asynchronous behaviour such as
56  longjmps and signals will interfere with the user code that is
57  invoked through ap_process_connection. The MPM may reserve some
58  signals for its use (i.e. SIGUSR1), but guarantees that these signals
59  are ignored when executing outside the MPM code itself. (This
60  allows broken user code that does not handle EINTR to function
61  properly.)
62 
63  The suggested server restart and stop behaviour will be "graceful".
64  However the MPM may choose to terminate processes when the user
65  requests a non-graceful restart/stop. When this occurs, the MPM kills
66  all threads with extreme prejudice, and destroys the pchild pool.
67  User cleanups registered in the pchild apr_pool_t will be invoked at
68  this point. (This can pose some complications, the user cleanups
69  are asynchronous behaviour not unlike longjmp/signal... but if the
70  admin is asking for a non-graceful shutdown, how much effort should
71  we put into doing it in a nice way?)
72 
73  unix/posix notes:
74  - The MPM does not set a SIGALRM handler, user code may use SIGALRM.
75  But the preferred method of handling timeouts is to use the
76  timeouts provided by the BUFF abstraction.
77  - The proper setting for SIGPIPE is SIG_IGN, if user code changes it
78  for any of their own processing, it must be restored to SIG_IGN
79  prior to executing or returning to any apache code.
80  TODO: add SIGPIPE debugging check somewhere to make sure it's SIG_IGN
81 */
82 
93 AP_DECLARE_HOOK(int, mpm, (apr_pool_t *pconf, apr_pool_t *plog, server_rec *server_conf))
94 
95 
109  const request_rec *r,
110  apr_proc_t *newproc,
111  const char *progname,
112  const char * const *args,
113  const char * const *env,
114  apr_procattr_t *attr,
115  apr_pool_t *p);
116 
125 #define AP_MPMQ_NOT_SUPPORTED 0
128 #define AP_MPMQ_STATIC 1
131 #define AP_MPMQ_DYNAMIC 2
140 #define AP_MPMQ_STARTING 0
141 #define AP_MPMQ_RUNNING 1
142 #define AP_MPMQ_STOPPING 2
143 
150 #define AP_MPMQ_MAX_DAEMON_USED 1
151 
152 #define AP_MPMQ_IS_THREADED 2
153 
154 #define AP_MPMQ_IS_FORKED 3
155 
156 #define AP_MPMQ_HARD_LIMIT_DAEMONS 4
157 
158 #define AP_MPMQ_HARD_LIMIT_THREADS 5
159 
160 #define AP_MPMQ_MAX_THREADS 6
161 
162 #define AP_MPMQ_MIN_SPARE_DAEMONS 7
163 
164 #define AP_MPMQ_MIN_SPARE_THREADS 8
165 
166 #define AP_MPMQ_MAX_SPARE_DAEMONS 9
167 
168 #define AP_MPMQ_MAX_SPARE_THREADS 10
169 
170 #define AP_MPMQ_MAX_REQUESTS_DAEMON 11
171 
172 #define AP_MPMQ_MAX_DAEMONS 12
173 
174 #define AP_MPMQ_MPM_STATE 13
175 
176 #define AP_MPMQ_IS_ASYNC 14
177 
178 #define AP_MPMQ_GENERATION 15
179 
180 #define AP_MPMQ_HAS_SERF 16
181 
182 #define AP_MPMQ_CAN_SUSPEND 17
183 
184 #define AP_MPMQ_CAN_POLL 18
185 
198 AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result);
199 
202 typedef void (ap_mpm_callback_fn_t)(void *baton);
203 
204 /* only added support in the Event MPM.... check for APR_ENOTIMPL */
206 /* only added support in the Event MPM.... check for APR_ENOTIMPL */
208  apr_time_t t, ap_mpm_callback_fn_t *cbfn, void *baton);
209 
223  ap_mpm_callback_fn_t *cbfn, void *baton);
224 
242  ap_mpm_callback_fn_t *tofn, void *baton, apr_time_t timeout);
243 
244 
254 
255 typedef enum mpm_child_status {
260 
281 AP_DECLARE_HOOK(void,child_status,(server_rec *s, pid_t pid, ap_generation_t gen,
282  int slot, mpm_child_status state))
283 
284 
293 
294 /* Defining GPROF when compiling uses the moncontrol() function to
295  * disable gprof profiling in the parent, and enable it only for
296  * request processing in children (or in one_process mode). It's
297  * absolutely required to get useful gprof results under linux
298  * because the profile itimers and such are disabled across a
299  * fork(). It's probably useful elsewhere as well.
300  */
301 #ifdef GPROF
302 extern void moncontrol(int);
303 #define AP_MONCONTROL(x) moncontrol(x)
304 #else
305 #define AP_MONCONTROL(x)
306 #endif
307 
308 #ifdef AP_ENABLE_EXCEPTION_HOOK
309 typedef struct ap_exception_info_t {
310  int sig;
311  pid_t pid;
312 } ap_exception_info_t;
313 
322 AP_DECLARE_HOOK(int,fatal_exception,(ap_exception_info_t *ei))
323 #endif /*AP_ENABLE_EXCEPTION_HOOK*/
324 
325 #ifdef __cplusplus
326 }
327 #endif
328 
329 #endif
330 
int ap_generation_t
Definition: scoreboard.h:78
void( ap_mpm_callback_fn_t)(void *baton)
Definition: ap_mpm.h:208
Definition: ap_mpm.h:262
Definition: apr_tables.h:62
apr_status_t ap_mpm_register_poll_callback(apr_array_header_t *pfds, ap_mpm_callback_fn_t *cbfn, void *baton)
int mpm(apr_pool_t *pconf, apr_pool_t *plog, server_rec *server_conf)
apr_status_t ap_mpm_register_poll_callback_timeout(apr_array_header_t *pfds, ap_mpm_callback_fn_t *cbfn, ap_mpm_callback_fn_t *tofn, void *baton, apr_time_t timeout)
void end_generation(server_rec *s, ap_generation_t gen)
Definition: ap_mpm.h:264
#define AP_DECLARE(x)
Definition: macros.h:1
Definition: apr_thread_proc.h:144
Structure to store things which are per connection.
Definition: httpd.h:1116
Definition: ap_mpm.h:263
apr_status_t ap_mpm_unregister_poll_callback(apr_array_header_t *pfds)
#define AP_DECLARE_HOOK(ret, name, args)
Definition: ap_hooks.h:74
apr_int64_t apr_time_t
Definition: apr_time.h:45
HTTP Daemon routines.
apr_status_t ap_mpm_query(int query_code, int *result)
apr_status_t ap_mpm_register_timed_callback(apr_time_t t, ap_mpm_callback_fn_t *cbfn, void *baton)
A structure to store information for each virtual server.
Definition: httpd.h:1310
void child_status(server_rec *s, pid_t pid, ap_generation_t gen, int slot, mpm_child_status state)
apr_status_t ap_os_create_privileged_process(const request_rec *r, apr_proc_t *newproc, const char *progname, const char *const *args, const char *const *env, apr_procattr_t *attr, apr_pool_t *p)
apr_pool_t * p
APR Thread and Process Library.
A structure that represents the current request.
Definition: httpd.h:806
Apache scoreboard library.
struct apr_pool_t apr_pool_t
Definition: apr_pools.h:60
int apr_status_t
Definition: apr_errno.h:44
request_rec * r
Definition: mod_dav.h:515
mpm_child_status
Definition: ap_mpm.h:261
Definition: apr_arch_threadproc.h:76
apr_status_t ap_mpm_resume_suspended(conn_rec *c)