1/* Licensed to the Apache Software Foundation (ASF) under one or more 2 * contributor license agreements. See the NOTICE file distributed with 3 * this work for additional information regarding copyright ownership. 4 * The ASF licenses this file to You under the Apache License, Version 2.0 5 * (the "License"); you may not use this file except in compliance with 6 * the License. You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17/* The purpose of this file is to store the code that MOST mpm's will need 18 * this does not mean a function only goes into this file if every MPM needs 19 * it. It means that if a function is needed by more than one MPM, and 20 * future maintenance would be served by making the code common, then the 21 * function belongs here. 22 * 23 * This is going in src/main because it is not platform specific, it is 24 * specific to multi-process servers, but NOT to Unix. Which is why it 25 * does not belong in src/os/unix 26 */ 27 28/** 29 * @file mpm_common.h 30 * @brief Multi-Processing Modules functions 31 * 32 * @defgroup APACHE_MPM Multi-Processing Modules 33 * @ingroup APACHE 34 * @{ 35 */ 36 37#ifndef APACHE_MPM_COMMON_H 38#define APACHE_MPM_COMMON_H 39 40#include "ap_config.h" 41 42#if APR_HAVE_NETINET_TCP_H 43#include <netinet/tcp.h> /* for TCP_NODELAY */ 44#endif 45 46#include "mpm.h" 47 48#ifdef __cplusplus 49extern "C" { 50#endif 51 52/* The maximum length of the queue of pending connections, as defined 53 * by listen(2). Under some systems, it should be increased if you 54 * are experiencing a heavy TCP SYN flood attack. 55 * 56 * It defaults to 511 instead of 512 because some systems store it 57 * as an 8-bit datatype; 512 truncated to 8-bits is 0, while 511 is 58 * 255 when truncated. 59 */ 60#ifndef DEFAULT_LISTENBACKLOG 61#define DEFAULT_LISTENBACKLOG 511 62#endif 63 64/* Signal used to gracefully restart */ 65#define AP_SIG_GRACEFUL SIGUSR1 66 67/* Signal used to gracefully restart (without SIG prefix) */ 68#define AP_SIG_GRACEFUL_SHORT USR1 69 70/* Signal used to gracefully restart (as a quoted string) */ 71#define AP_SIG_GRACEFUL_STRING "SIGUSR1" 72 73/* Signal used to gracefully stop */ 74#define AP_SIG_GRACEFUL_STOP SIGWINCH 75 76/* Signal used to gracefully stop (without SIG prefix) */ 77#define AP_SIG_GRACEFUL_STOP_SHORT WINCH 78 79/* Signal used to gracefully stop (as a quoted string) */ 80#define AP_SIG_GRACEFUL_STOP_STRING "SIGWINCH" 81 82/** 83 * Make sure all child processes that have been spawned by the parent process 84 * have died. This includes process registered as "other_children". 85 * @warning This is only defined if the MPM defines 86 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES 87 * @param terminate Either 1 or 0. If 1, send the child processes SIGTERM 88 * each time through the loop. If 0, give the process time to die 89 * on its own before signalling it. 90 * @tip This function requires that some macros are defined by the MPM: <pre> 91 * MPM_CHILD_PID -- Get the pid from the specified spot in the scoreboard 92 * MPM_NOTE_CHILD_KILLED -- Note the child died in the scoreboard 93 * </pre> 94 * @tip The MPM child processes which are reclaimed are those listed 95 * in the scoreboard as well as those currently registered via 96 * ap_register_extra_mpm_process(). 97 */ 98#ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES 99void ap_reclaim_child_processes(int terminate); 100#endif 101 102/** 103 * Catch any child processes that have been spawned by the parent process 104 * which have exited. This includes processes registered as "other_children". 105 * @warning This is only defined if the MPM defines 106 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES 107 * @tip This function requires that some macros are defined by the MPM: <pre> 108 * MPM_CHILD_PID -- Get the pid from the specified spot in the scoreboard 109 * MPM_NOTE_CHILD_KILLED -- Note the child died in the scoreboard 110 * </pre> 111 * @tip The MPM child processes which are relieved are those listed 112 * in the scoreboard as well as those currently registered via 113 * ap_register_extra_mpm_process(). 114 */ 115#ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES 116void ap_relieve_child_processes(void); 117#endif 118 119/** 120 * Tell ap_reclaim_child_processes() and ap_relieve_child_processes() about 121 * an MPM child process which has no entry in the scoreboard. 122 * @warning This is only defined if the MPM defines 123 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES 124 * @param pid The process id of an MPM child process which should be 125 * reclaimed when ap_reclaim_child_processes() is called. 126 * @tip If an extra MPM child process terminates prior to calling 127 * ap_reclaim_child_processes(), remove it from the list of such processes 128 * by calling ap_unregister_extra_mpm_process(). 129 */ 130#ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES 131void ap_register_extra_mpm_process(pid_t pid); 132#endif 133 134/** 135 * Unregister an MPM child process which was previously registered by a 136 * call to ap_register_extra_mpm_process(). 137 * @warning This is only defined if the MPM defines 138 * AP_MPM_WANT_RECLAIM_CHILD_PROCESSES 139 * @param pid The process id of an MPM child process which no longer needs to 140 * be reclaimed. 141 * @return 1 if the process was found and removed, 0 otherwise 142 */ 143#ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES 144int ap_unregister_extra_mpm_process(pid_t pid); 145#endif 146 147/** 148 * Safely signal an MPM child process, if the process is in the 149 * current process group. Otherwise fail. 150 * @param pid the process id of a child process to signal 151 * @param sig the signal number to send 152 * @return APR_SUCCESS if signal is sent, otherwise an error as per kill(3); 153 * APR_EINVAL is returned if passed either an invalid (< 1) pid, or if 154 * the pid is not in the current process group 155 */ 156#ifdef AP_MPM_WANT_RECLAIM_CHILD_PROCESSES 157apr_status_t ap_mpm_safe_kill(pid_t pid, int sig); 158#endif 159 160/** 161 * Determine if any child process has died. If no child process died, then 162 * this process sleeps for the amount of time specified by the MPM defined 163 * macro SCOREBOARD_MAINTENANCE_INTERVAL. 164 * @param status The return code if a process has died 165 * @param ret The process id of the process that died 166 * @param p The pool to allocate out of 167 */ 168#ifdef AP_MPM_WANT_WAIT_OR_TIMEOUT 169void ap_wait_or_timeout(apr_exit_why_e *status, int *exitcode, apr_proc_t *ret, 170 apr_pool_t *p); 171#endif 172 173/** 174 * Log why a child died to the error log, if the child died without the 175 * parent signalling it. 176 * @param pid The child that has died 177 * @param status The status returned from ap_wait_or_timeout 178 * @return 0 on success, APEXIT_CHILDFATAL if MPM should terminate 179 */ 180#ifdef AP_MPM_WANT_PROCESS_CHILD_STATUS 181int ap_process_child_status(apr_proc_t *pid, apr_exit_why_e why, int status); 182#endif 183 184#if defined(TCP_NODELAY) && !defined(MPE) && !defined(TPF) 185/** 186 * Turn off the nagle algorithm for the specified socket. The nagle algorithm 187 * says that we should delay sending partial packets in the hopes of getting 188 * more data. There are bad interactions between persistent connections and 189 * Nagle's algorithm that have severe performance penalties. 190 * @param s The socket to disable nagle for. 191 */ 192void ap_sock_disable_nagle(apr_socket_t *s); 193#else 194#define ap_sock_disable_nagle(s) /* NOOP */ 195#endif 196 197#ifdef HAVE_GETPWNAM 198/** 199 * Convert a username to a numeric ID 200 * @param name The name to convert 201 * @return The user id corresponding to a name 202 * @deffunc uid_t ap_uname2id(const char *name) 203 */ 204AP_DECLARE(uid_t) ap_uname2id(const char *name); 205#endif 206 207#ifdef HAVE_GETGRNAM 208/** 209 * Convert a group name to a numeric ID 210 * @param name The name to convert 211 * @return The group id corresponding to a name 212 * @deffunc gid_t ap_gname2id(const char *name) 213 */ 214AP_DECLARE(gid_t) ap_gname2id(const char *name); 215#endif 216 217#define AP_MPM_HARD_LIMITS_FILE APACHE_MPM_DIR "/mpm_default.h" 218 219#ifndef HAVE_INITGROUPS 220/** 221 * The initgroups() function initializes the group access list by reading the 222 * group database /etc/group and using all groups of which user is a member. 223 * The additional group basegid is also added to the list. 224 * @param name The user name - must be non-NULL 225 * @param basegid The basegid to add 226 * @return returns 0 on success 227 * @fn int initgroups(const char *name, gid_t basegid) 228 */ 229int initgroups(const char *name, gid_t basegid); 230#endif 231 232#ifdef AP_MPM_USES_POD 233 234typedef struct ap_pod_t ap_pod_t; 235 236struct ap_pod_t { 237 apr_file_t *pod_in; 238 apr_file_t *pod_out; 239 apr_pool_t *p; 240}; 241 242/** 243 * Open the pipe-of-death. The pipe of death is used to tell all child 244 * processes that it is time to die gracefully. 245 * @param p The pool to use for allocating the pipe 246 */ 247AP_DECLARE(apr_status_t) ap_mpm_pod_open(apr_pool_t *p, ap_pod_t **pod); 248 249/** 250 * Check the pipe to determine if the process has been signalled to die. 251 */ 252AP_DECLARE(apr_status_t) ap_mpm_pod_check(ap_pod_t *pod); 253 254/** 255 * Close the pipe-of-death 256 */ 257AP_DECLARE(apr_status_t) ap_mpm_pod_close(ap_pod_t *pod); 258 259/** 260 * Write data to the pipe-of-death, signalling that one child process 261 * should die. 262 * @param p The pool to use when allocating any required structures. 263 */ 264AP_DECLARE(apr_status_t) ap_mpm_pod_signal(ap_pod_t *pod); 265 266/** 267 * Write data to the pipe-of-death, signalling that all child process 268 * should die. 269 * @param p The pool to use when allocating any required structures. 270 * @param num The number of child processes to kill 271 */ 272AP_DECLARE(void) ap_mpm_pod_killpg(ap_pod_t *pod, int num); 273#endif 274 275/* 276 * These data members are common to all mpms. Each new mpm 277 * should either use the appropriate ap_mpm_set_* function 278 * in their command table or create their own for custom or 279 * OS specific needs. These should work for most. 280 */ 281 282/** 283 * The maximum number of requests each child thread or 284 * process handles before dying off 285 */ 286#ifdef AP_MPM_WANT_SET_MAX_REQUESTS 287extern int ap_max_requests_per_child; 288const char *ap_mpm_set_max_requests(cmd_parms *cmd, void *dummy, 289 const char *arg); 290#endif 291 292/** 293 * The filename used to store the process id. 294 */ 295#ifdef AP_MPM_WANT_SET_PIDFILE 296extern const char *ap_pid_fname; 297const char *ap_mpm_set_pidfile(cmd_parms *cmd, void *dummy, 298 const char *arg); 299#endif 300 301/** 302 * The name of lockfile used when Apache needs to lock the accept() call. 303 */ 304#ifdef AP_MPM_WANT_SET_LOCKFILE 305extern const char *ap_lock_fname; 306const char *ap_mpm_set_lockfile(cmd_parms *cmd, void *dummy, 307 const char *arg); 308#endif 309 310/** 311 * The system mutex implementation to use for the accept mutex. 312 */ 313#ifdef AP_MPM_WANT_SET_ACCEPT_LOCK_MECH 314extern apr_lockmech_e ap_accept_lock_mech; 315extern const char ap_valid_accept_mutex_string[]; 316const char *ap_mpm_set_accept_lock_mech(cmd_parms *cmd, void *dummy, 317 const char *arg); 318#endif 319 320/* 321 * Set the scorboard file. 322 */ 323#ifdef AP_MPM_WANT_SET_SCOREBOARD 324const char *ap_mpm_set_scoreboard(cmd_parms *cmd, void *dummy, 325 const char *arg); 326#endif 327 328/* 329 * The directory that the server changes directory to dump core. 330 */ 331#ifdef AP_MPM_WANT_SET_COREDUMPDIR 332extern char ap_coredump_dir[MAX_STRING_LEN]; 333extern int ap_coredumpdir_configured; 334const char *ap_mpm_set_coredumpdir(cmd_parms *cmd, void *dummy, 335 const char *arg); 336#endif 337 338/** 339 * Set the timeout period for a graceful shutdown. 340 */ 341#ifdef AP_MPM_WANT_SET_GRACEFUL_SHUTDOWN 342extern int ap_graceful_shutdown_timeout; 343const char *ap_mpm_set_graceful_shutdown(cmd_parms *cmd, void *dummy, 344 const char *arg); 345#define AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND \ 346AP_INIT_TAKE1("GracefulShutdownTimeout", ap_mpm_set_graceful_shutdown, NULL, \ 347 RSRC_CONF, "Maximum time in seconds to wait for child " \ 348 "processes to complete transactions during shutdown") 349#endif 350 351 352#ifdef AP_MPM_WANT_SIGNAL_SERVER 353int ap_signal_server(int *, apr_pool_t *); 354void ap_mpm_rewrite_args(process_rec *); 355#endif 356 357#ifdef AP_MPM_WANT_SET_MAX_MEM_FREE 358extern apr_uint32_t ap_max_mem_free; 359extern const char *ap_mpm_set_max_mem_free(cmd_parms *cmd, void *dummy, 360 const char *arg); 361#endif 362 363#ifdef AP_MPM_WANT_SET_STACKSIZE 364extern apr_size_t ap_thread_stacksize; 365extern const char *ap_mpm_set_thread_stacksize(cmd_parms *cmd, void *dummy, 366 const char *arg); 367#endif 368 369#ifdef AP_MPM_WANT_FATAL_SIGNAL_HANDLER 370extern apr_status_t ap_fatal_signal_setup(server_rec *s, apr_pool_t *pconf); 371extern apr_status_t ap_fatal_signal_child_setup(server_rec *s); 372#endif 373 374#if AP_ENABLE_EXCEPTION_HOOK 375extern const char *ap_mpm_set_exception_hook(cmd_parms *cmd, void *dummy, 376 const char *arg); 377#endif 378 379AP_DECLARE_HOOK(int,monitor,(apr_pool_t *p)) 380 381#ifdef __cplusplus 382} 383#endif 384 385#endif /* !APACHE_MPM_COMMON_H */ 386/** @} */ 387