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#ifndef APR_THREAD_PROC_H
18#define APR_THREAD_PROC_H
19
20/**
21 * @file apr_thread_proc.h
22 * @brief APR Thread and Process Library
23 */
24
25#include "apr.h"
26#include "apr_file_io.h"
27#include "apr_pools.h"
28#include "apr_errno.h"
29
30#if APR_HAVE_STRUCT_RLIMIT
31#include <sys/time.h>
32#include <sys/resource.h>
33#endif
34
35#ifdef __cplusplus
36extern "C" {
37#endif /* __cplusplus */
38
39/**
40 * @defgroup apr_thread_proc Threads and Process Functions
41 * @ingroup APR
42 * @{
43 */
44
45typedef enum {
46    APR_SHELLCMD,           /**< use the shell to invoke the program */
47    APR_PROGRAM,            /**< invoke the program directly, no copied env */
48    APR_PROGRAM_ENV,        /**< invoke the program, replicating our environment */
49    APR_PROGRAM_PATH,       /**< find program on PATH, use our environment */
50    APR_SHELLCMD_ENV        /**< use the shell to invoke the program,
51                             *   replicating our environment
52                             */
53} apr_cmdtype_e;
54
55typedef enum {
56    APR_WAIT,           /**< wait for the specified process to finish */
57    APR_NOWAIT          /**< do not wait -- just see if it has finished */
58} apr_wait_how_e;
59
60/* I am specifically calling out the values so that the macros below make
61 * more sense.  Yes, I know I don't need to, but I am hoping this makes what
62 * I am doing more clear.  If you want to add more reasons to exit, continue
63 * to use bitmasks.
64 */
65typedef enum {
66    APR_PROC_EXIT = 1,          /**< process exited normally */
67    APR_PROC_SIGNAL = 2,        /**< process exited due to a signal */
68    APR_PROC_SIGNAL_CORE = 4    /**< process exited and dumped a core file */
69} apr_exit_why_e;
70
71/** did we exit the process */
72#define APR_PROC_CHECK_EXIT(x)        (x & APR_PROC_EXIT)
73/** did we get a signal */
74#define APR_PROC_CHECK_SIGNALED(x)    (x & APR_PROC_SIGNAL)
75/** did we get core */
76#define APR_PROC_CHECK_CORE_DUMP(x)   (x & APR_PROC_SIGNAL_CORE)
77
78/** @see apr_procattr_io_set */
79#define APR_NO_PIPE          0
80/** @see apr_procattr_io_set and apr_file_pipe_create_ex */
81#define APR_FULL_BLOCK       1
82/** @see apr_procattr_io_set and apr_file_pipe_create_ex */
83#define APR_FULL_NONBLOCK    2
84/** @see apr_procattr_io_set */
85#define APR_PARENT_BLOCK     3
86/** @see apr_procattr_io_set */
87#define APR_CHILD_BLOCK      4
88/** @see apr_procattr_io_set */
89#define APR_NO_FILE          8
90
91/** @see apr_file_pipe_create_ex */
92#define APR_READ_BLOCK       3
93/** @see apr_file_pipe_create_ex */
94#define APR_WRITE_BLOCK      4
95
96/** @see apr_procattr_io_set
97 * @note Win32 only effective with version 1.2.12, portably introduced in 1.3.0
98 */
99#define APR_NO_FILE          8
100
101/** @see apr_procattr_limit_set */
102#define APR_LIMIT_CPU        0
103/** @see apr_procattr_limit_set */
104#define APR_LIMIT_MEM        1
105/** @see apr_procattr_limit_set */
106#define APR_LIMIT_NPROC      2
107/** @see apr_procattr_limit_set */
108#define APR_LIMIT_NOFILE     3
109
110/**
111 * @defgroup APR_OC Other Child Flags
112 * @{
113 */
114#define APR_OC_REASON_DEATH         0     /**< child has died, caller must call
115                                           * unregister still */
116#define APR_OC_REASON_UNWRITABLE    1     /**< write_fd is unwritable */
117#define APR_OC_REASON_RESTART       2     /**< a restart is occuring, perform
118                                           * any necessary cleanup (including
119                                           * sending a special signal to child)
120                                           */
121#define APR_OC_REASON_UNREGISTER    3     /**< unregister has been called, do
122                                           * whatever is necessary (including
123                                           * kill the child) */
124#define APR_OC_REASON_LOST          4     /**< somehow the child exited without
125                                           * us knowing ... buggy os? */
126#define APR_OC_REASON_RUNNING       5     /**< a health check is occuring,
127                                           * for most maintainence functions
128                                           * this is a no-op.
129                                           */
130/** @} */
131
132/** The APR process type */
133typedef struct apr_proc_t {
134    /** The process ID */
135    pid_t pid;
136    /** Parent's side of pipe to child's stdin */
137    apr_file_t *in;
138    /** Parent's side of pipe to child's stdout */
139    apr_file_t *out;
140    /** Parent's side of pipe to child's stdouterr */
141    apr_file_t *err;
142#if APR_HAS_PROC_INVOKED || defined(DOXYGEN)
143    /** Diagnositics/debugging string of the command invoked for
144     *  this process [only present if APR_HAS_PROC_INVOKED is true]
145     * @remark Only enabled on Win32 by default.
146     * @bug This should either always or never be present in release
147     * builds - since it breaks binary compatibility.  We may enable
148     * it always in APR 1.0 yet leave it undefined in most cases.
149     */
150    char *invoked;
151#endif
152#if defined(WIN32) || defined(DOXYGEN)
153    /** (Win32 only) Creator's handle granting access to the process
154     * @remark This handle is closed and reset to NULL in every case
155     * corresponding to a waitpid() on Unix which returns the exit status.
156     * Therefore Win32 correspond's to Unix's zombie reaping characteristics
157     * and avoids potential handle leaks.
158     */
159    HANDLE hproc;
160#endif
161} apr_proc_t;
162
163/**
164 * The prototype for APR child errfn functions.  (See the description
165 * of apr_procattr_child_errfn_set() for more information.)
166 * It is passed the following parameters:
167 * @param pool Pool associated with the apr_proc_t.  If your child
168 *             error function needs user data, associate it with this
169 *             pool.
170 * @param err APR error code describing the error
171 * @param description Text description of type of processing which failed
172 */
173typedef void (apr_child_errfn_t)(apr_pool_t *proc, apr_status_t err,
174                                 const char *description);
175
176/** Opaque Thread structure. */
177typedef struct apr_thread_t           apr_thread_t;
178
179/** Opaque Thread attributes structure. */
180typedef struct apr_threadattr_t       apr_threadattr_t;
181
182/** Opaque Process attributes structure. */
183typedef struct apr_procattr_t         apr_procattr_t;
184
185/** Opaque control variable for one-time atomic variables.  */
186typedef struct apr_thread_once_t      apr_thread_once_t;
187
188/** Opaque thread private address space. */
189typedef struct apr_threadkey_t        apr_threadkey_t;
190
191/** Opaque record of child process. */
192typedef struct apr_other_child_rec_t  apr_other_child_rec_t;
193
194/**
195 * The prototype for any APR thread worker functions.
196 */
197typedef void *(APR_THREAD_FUNC *apr_thread_start_t)(apr_thread_t*, void*);
198
199typedef enum {
200    APR_KILL_NEVER,             /**< process is never sent any signals */
201    APR_KILL_ALWAYS,            /**< process is sent SIGKILL on apr_pool_t cleanup */
202    APR_KILL_AFTER_TIMEOUT,     /**< SIGTERM, wait 3 seconds, SIGKILL */
203    APR_JUST_WAIT,              /**< wait forever for the process to complete */
204    APR_KILL_ONLY_ONCE          /**< send SIGTERM and then wait */
205} apr_kill_conditions_e;
206
207/* Thread Function definitions */
208
209#if APR_HAS_THREADS
210
211/**
212 * Create and initialize a new threadattr variable
213 * @param new_attr The newly created threadattr.
214 * @param cont The pool to use
215 */
216APR_DECLARE(apr_status_t) apr_threadattr_create(apr_threadattr_t **new_attr,
217                                                apr_pool_t *cont);
218
219/**
220 * Set if newly created threads should be created in detached state.
221 * @param attr The threadattr to affect
222 * @param on Non-zero if detached threads should be created.
223 */
224APR_DECLARE(apr_status_t) apr_threadattr_detach_set(apr_threadattr_t *attr,
225                                                    apr_int32_t on);
226
227/**
228 * Get the detach state for this threadattr.
229 * @param attr The threadattr to reference
230 * @return APR_DETACH if threads are to be detached, or APR_NOTDETACH
231 * if threads are to be joinable.
232 */
233APR_DECLARE(apr_status_t) apr_threadattr_detach_get(apr_threadattr_t *attr);
234
235/**
236 * Set the stack size of newly created threads.
237 * @param attr The threadattr to affect
238 * @param stacksize The stack size in bytes
239 */
240APR_DECLARE(apr_status_t) apr_threadattr_stacksize_set(apr_threadattr_t *attr,
241                                                       apr_size_t stacksize);
242
243/**
244 * Set the stack guard area size of newly created threads.
245 * @param attr The threadattr to affect
246 * @param guardsize The stack guard area size in bytes
247 * @note Thread library implementations commonly use a "guard area"
248 * after each thread's stack which is not readable or writable such that
249 * stack overflows cause a segfault; this consumes e.g. 4K of memory
250 * and increases memory management overhead.  Setting the guard area
251 * size to zero hence trades off reliable behaviour on stack overflow
252 * for performance. */
253APR_DECLARE(apr_status_t) apr_threadattr_guardsize_set(apr_threadattr_t *attr,
254                                                       apr_size_t guardsize);
255
256/**
257 * Create a new thread of execution
258 * @param new_thread The newly created thread handle.
259 * @param attr The threadattr to use to determine how to create the thread
260 * @param func The function to start the new thread in
261 * @param data Any data to be passed to the starting function
262 * @param cont The pool to use
263 */
264APR_DECLARE(apr_status_t) apr_thread_create(apr_thread_t **new_thread,
265                                            apr_threadattr_t *attr,
266                                            apr_thread_start_t func,
267                                            void *data, apr_pool_t *cont);
268
269/**
270 * stop the current thread
271 * @param thd The thread to stop
272 * @param retval The return value to pass back to any thread that cares
273 */
274APR_DECLARE(apr_status_t) apr_thread_exit(apr_thread_t *thd,
275                                          apr_status_t retval);
276
277/**
278 * block until the desired thread stops executing.
279 * @param retval The return value from the dead thread.
280 * @param thd The thread to join
281 */
282APR_DECLARE(apr_status_t) apr_thread_join(apr_status_t *retval,
283                                          apr_thread_t *thd);
284
285/**
286 * force the current thread to yield the processor
287 */
288APR_DECLARE(void) apr_thread_yield(void);
289
290/**
291 * Initialize the control variable for apr_thread_once.  If this isn't
292 * called, apr_initialize won't work.
293 * @param control The control variable to initialize
294 * @param p The pool to allocate data from.
295 */
296APR_DECLARE(apr_status_t) apr_thread_once_init(apr_thread_once_t **control,
297                                               apr_pool_t *p);
298
299/**
300 * Run the specified function one time, regardless of how many threads
301 * call it.
302 * @param control The control variable.  The same variable should
303 *                be passed in each time the function is tried to be
304 *                called.  This is how the underlying functions determine
305 *                if the function has ever been called before.
306 * @param func The function to call.
307 */
308APR_DECLARE(apr_status_t) apr_thread_once(apr_thread_once_t *control,
309                                          void (*func)(void));
310
311/**
312 * detach a thread
313 * @param thd The thread to detach
314 */
315APR_DECLARE(apr_status_t) apr_thread_detach(apr_thread_t *thd);
316
317/**
318 * Return the pool associated with the current thread.
319 * @param data The user data associated with the thread.
320 * @param key The key to associate with the data
321 * @param thread The currently open thread.
322 */
323APR_DECLARE(apr_status_t) apr_thread_data_get(void **data, const char *key,
324                                             apr_thread_t *thread);
325
326/**
327 * Return the pool associated with the current thread.
328 * @param data The user data to associate with the thread.
329 * @param key The key to use for associating the data with the thread
330 * @param cleanup The cleanup routine to use when the thread is destroyed.
331 * @param thread The currently open thread.
332 */
333APR_DECLARE(apr_status_t) apr_thread_data_set(void *data, const char *key,
334                                             apr_status_t (*cleanup) (void *),
335                                             apr_thread_t *thread);
336
337/**
338 * Create and initialize a new thread private address space
339 * @param key The thread private handle.
340 * @param dest The destructor to use when freeing the private memory.
341 * @param cont The pool to use
342 */
343APR_DECLARE(apr_status_t) apr_threadkey_private_create(apr_threadkey_t **key,
344                                                    void (*dest)(void *),
345                                                    apr_pool_t *cont);
346
347/**
348 * Get a pointer to the thread private memory
349 * @param new_mem The data stored in private memory
350 * @param key The handle for the desired thread private memory
351 */
352APR_DECLARE(apr_status_t) apr_threadkey_private_get(void **new_mem,
353                                                 apr_threadkey_t *key);
354
355/**
356 * Set the data to be stored in thread private memory
357 * @param priv The data to be stored in private memory
358 * @param key The handle for the desired thread private memory
359 */
360APR_DECLARE(apr_status_t) apr_threadkey_private_set(void *priv,
361                                                 apr_threadkey_t *key);
362
363/**
364 * Free the thread private memory
365 * @param key The handle for the desired thread private memory
366 */
367APR_DECLARE(apr_status_t) apr_threadkey_private_delete(apr_threadkey_t *key);
368
369/**
370 * Return the pool associated with the current threadkey.
371 * @param data The user data associated with the threadkey.
372 * @param key The key associated with the data
373 * @param threadkey The currently open threadkey.
374 */
375APR_DECLARE(apr_status_t) apr_threadkey_data_get(void **data, const char *key,
376                                                apr_threadkey_t *threadkey);
377
378/**
379 * Return the pool associated with the current threadkey.
380 * @param data The data to set.
381 * @param key The key to associate with the data.
382 * @param cleanup The cleanup routine to use when the file is destroyed.
383 * @param threadkey The currently open threadkey.
384 */
385APR_DECLARE(apr_status_t) apr_threadkey_data_set(void *data, const char *key,
386                                                apr_status_t (*cleanup) (void *),
387                                                apr_threadkey_t *threadkey);
388
389#endif
390
391/**
392 * Create and initialize a new procattr variable
393 * @param new_attr The newly created procattr.
394 * @param cont The pool to use
395 */
396APR_DECLARE(apr_status_t) apr_procattr_create(apr_procattr_t **new_attr,
397                                                  apr_pool_t *cont);
398
399/**
400 * Determine if any of stdin, stdout, or stderr should be linked to pipes
401 * when starting a child process.
402 * @param attr The procattr we care about.
403 * @param in Should stdin be a pipe back to the parent?
404 * @param out Should stdout be a pipe back to the parent?
405 * @param err Should stderr be a pipe back to the parent?
406 * @note If APR_NO_PIPE, there will be no special channel, the child
407 * inherits the parent's corresponding stdio stream.  If APR_NO_FILE is
408 * specified, that corresponding stream is closed in the child (and will
409 * be INVALID_HANDLE_VALUE when inspected on Win32). This can have ugly
410 * side effects, as the next file opened in the child on Unix will fall
411 * into the stdio stream fd slot!
412 */
413APR_DECLARE(apr_status_t) apr_procattr_io_set(apr_procattr_t *attr,
414                                             apr_int32_t in, apr_int32_t out,
415                                             apr_int32_t err);
416
417/**
418 * Set the child_in and/or parent_in values to existing apr_file_t values.
419 * @param attr The procattr we care about.
420 * @param child_in apr_file_t value to use as child_in. Must be a valid file.
421 * @param parent_in apr_file_t value to use as parent_in. Must be a valid file.
422 * @remark  This is NOT a required initializer function. This is
423 *          useful if you have already opened a pipe (or multiple files)
424 *          that you wish to use, perhaps persistently across multiple
425 *          process invocations - such as a log file. You can save some
426 *          extra function calls by not creating your own pipe since this
427 *          creates one in the process space for you.
428 * @bug Note that calling this function with two NULL files on some platforms
429 * creates an APR_FULL_BLOCK pipe, but this behavior is neither portable nor
430 * is it supported.  @see apr_procattr_io_set instead for simple pipes.
431 */
432APR_DECLARE(apr_status_t) apr_procattr_child_in_set(struct apr_procattr_t *attr,
433                                                  apr_file_t *child_in,
434                                                  apr_file_t *parent_in);
435
436/**
437 * Set the child_out and parent_out values to existing apr_file_t values.
438 * @param attr The procattr we care about.
439 * @param child_out apr_file_t value to use as child_out. Must be a valid file.
440 * @param parent_out apr_file_t value to use as parent_out. Must be a valid file.
441 * @remark This is NOT a required initializer function. This is
442 *         useful if you have already opened a pipe (or multiple files)
443 *         that you wish to use, perhaps persistently across multiple
444 *         process invocations - such as a log file.
445 * @bug Note that calling this function with two NULL files on some platforms
446 * creates an APR_FULL_BLOCK pipe, but this behavior is neither portable nor
447 * is it supported.  @see apr_procattr_io_set instead for simple pipes.
448 */
449APR_DECLARE(apr_status_t) apr_procattr_child_out_set(struct apr_procattr_t *attr,
450                                                   apr_file_t *child_out,
451                                                   apr_file_t *parent_out);
452
453/**
454 * Set the child_err and parent_err values to existing apr_file_t values.
455 * @param attr The procattr we care about.
456 * @param child_err apr_file_t value to use as child_err. Must be a valid file.
457 * @param parent_err apr_file_t value to use as parent_err. Must be a valid file.
458 * @remark This is NOT a required initializer function. This is
459 *         useful if you have already opened a pipe (or multiple files)
460 *         that you wish to use, perhaps persistently across multiple
461 *         process invocations - such as a log file.
462 * @bug Note that calling this function with two NULL files on some platforms
463 * creates an APR_FULL_BLOCK pipe, but this behavior is neither portable nor
464 * is it supported.  @see apr_procattr_io_set instead for simple pipes.
465 */
466APR_DECLARE(apr_status_t) apr_procattr_child_err_set(struct apr_procattr_t *attr,
467                                                   apr_file_t *child_err,
468                                                   apr_file_t *parent_err);
469
470/**
471 * Set which directory the child process should start executing in.
472 * @param attr The procattr we care about.
473 * @param dir Which dir to start in.  By default, this is the same dir as
474 *            the parent currently resides in, when the createprocess call
475 *            is made.
476 */
477APR_DECLARE(apr_status_t) apr_procattr_dir_set(apr_procattr_t *attr,
478                                              const char *dir);
479
480/**
481 * Set what type of command the child process will call.
482 * @param attr The procattr we care about.
483 * @param cmd The type of command.  One of:
484 * <PRE>
485 *            APR_SHELLCMD     --  Anything that the shell can handle
486 *            APR_PROGRAM      --  Executable program   (default)
487 *            APR_PROGRAM_ENV  --  Executable program, copy environment
488 *            APR_PROGRAM_PATH --  Executable program on PATH, copy env
489 * </PRE>
490 */
491APR_DECLARE(apr_status_t) apr_procattr_cmdtype_set(apr_procattr_t *attr,
492                                                  apr_cmdtype_e cmd);
493
494/**
495 * Determine if the child should start in detached state.
496 * @param attr The procattr we care about.
497 * @param detach Should the child start in detached state?  Default is no.
498 */
499APR_DECLARE(apr_status_t) apr_procattr_detach_set(apr_procattr_t *attr,
500                                                 apr_int32_t detach);
501
502#if APR_HAVE_STRUCT_RLIMIT
503/**
504 * Set the Resource Utilization limits when starting a new process.
505 * @param attr The procattr we care about.
506 * @param what Which limit to set, one of:
507 * <PRE>
508 *                 APR_LIMIT_CPU
509 *                 APR_LIMIT_MEM
510 *                 APR_LIMIT_NPROC
511 *                 APR_LIMIT_NOFILE
512 * </PRE>
513 * @param limit Value to set the limit to.
514 */
515APR_DECLARE(apr_status_t) apr_procattr_limit_set(apr_procattr_t *attr,
516                                                apr_int32_t what,
517                                                struct rlimit *limit);
518#endif
519
520/**
521 * Specify an error function to be called in the child process if APR
522 * encounters an error in the child prior to running the specified program.
523 * @param attr The procattr describing the child process to be created.
524 * @param errfn The function to call in the child process.
525 * @remark At the present time, it will only be called from apr_proc_create()
526 *         on platforms where fork() is used.  It will never be called on other
527 *         platforms, on those platforms apr_proc_create() will return the error
528 *         in the parent process rather than invoke the callback in the now-forked
529 *         child process.
530 */
531APR_DECLARE(apr_status_t) apr_procattr_child_errfn_set(apr_procattr_t *attr,
532                                                       apr_child_errfn_t *errfn);
533
534/**
535 * Specify that apr_proc_create() should do whatever it can to report
536 * failures to the caller of apr_proc_create(), rather than find out in
537 * the child.
538 * @param attr The procattr describing the child process to be created.
539 * @param chk Flag to indicate whether or not extra work should be done
540 *            to try to report failures to the caller.
541 * @remark This flag only affects apr_proc_create() on platforms where
542 *         fork() is used.  This leads to extra overhead in the calling
543 *         process, but that may help the application handle such
544 *         errors more gracefully.
545 */
546APR_DECLARE(apr_status_t) apr_procattr_error_check_set(apr_procattr_t *attr,
547                                                       apr_int32_t chk);
548
549/**
550 * Determine if the child should start in its own address space or using the
551 * current one from its parent
552 * @param attr The procattr we care about.
553 * @param addrspace Should the child start in its own address space?  Default
554 *                  is no on NetWare and yes on other platforms.
555 */
556APR_DECLARE(apr_status_t) apr_procattr_addrspace_set(apr_procattr_t *attr,
557                                                       apr_int32_t addrspace);
558
559/**
560 * Set the username used for running process
561 * @param attr The procattr we care about.
562 * @param username The username used
563 * @param password User password if needed. Password is needed on WIN32
564 *                 or any other platform having
565 *                 APR_PROCATTR_USER_SET_REQUIRES_PASSWORD set.
566 */
567APR_DECLARE(apr_status_t) apr_procattr_user_set(apr_procattr_t *attr,
568                                                const char *username,
569                                                const char *password);
570
571/**
572 * Set the group used for running process
573 * @param attr The procattr we care about.
574 * @param groupname The group name  used
575 */
576APR_DECLARE(apr_status_t) apr_procattr_group_set(apr_procattr_t *attr,
577                                                 const char *groupname);
578
579
580#if APR_HAS_FORK
581/**
582 * This is currently the only non-portable call in APR.  This executes
583 * a standard unix fork.
584 * @param proc The resulting process handle.
585 * @param cont The pool to use.
586 * @remark returns APR_INCHILD for the child, and APR_INPARENT for the parent
587 * or an error.
588 */
589APR_DECLARE(apr_status_t) apr_proc_fork(apr_proc_t *proc, apr_pool_t *cont);
590#endif
591
592/**
593 * Create a new process and execute a new program within that process.
594 * @param new_proc The resulting process handle.
595 * @param progname The program to run
596 * @param args the arguments to pass to the new program.  The first
597 *             one should be the program name.
598 * @param env The new environment table for the new process.  This
599 *            should be a list of NULL-terminated strings. This argument
600 *            is ignored for APR_PROGRAM_ENV, APR_PROGRAM_PATH, and
601 *            APR_SHELLCMD_ENV types of commands.
602 * @param attr the procattr we should use to determine how to create the new
603 *         process
604 * @param pool The pool to use.
605 * @note This function returns without waiting for the new process to terminate;
606 * use apr_proc_wait for that.
607 */
608APR_DECLARE(apr_status_t) apr_proc_create(apr_proc_t *new_proc,
609                                          const char *progname,
610                                          const char * const *args,
611                                          const char * const *env,
612                                          apr_procattr_t *attr,
613                                          apr_pool_t *pool);
614
615/**
616 * Wait for a child process to die
617 * @param proc The process handle that corresponds to the desired child process
618 * @param exitcode The returned exit status of the child, if a child process
619 *                 dies, or the signal that caused the child to die.
620 *                 On platforms that don't support obtaining this information,
621 *                 the status parameter will be returned as APR_ENOTIMPL.
622 * @param exitwhy Why the child died, the bitwise or of:
623 * <PRE>
624 *            APR_PROC_EXIT         -- process terminated normally
625 *            APR_PROC_SIGNAL       -- process was killed by a signal
626 *            APR_PROC_SIGNAL_CORE  -- process was killed by a signal, and
627 *                                     generated a core dump.
628 * </PRE>
629 * @param waithow How should we wait.  One of:
630 * <PRE>
631 *            APR_WAIT   -- block until the child process dies.
632 *            APR_NOWAIT -- return immediately regardless of if the
633 *                          child is dead or not.
634 * </PRE>
635 * @remark The childs status is in the return code to this process.  It is one of:
636 * <PRE>
637 *            APR_CHILD_DONE     -- child is no longer running.
638 *            APR_CHILD_NOTDONE  -- child is still running.
639 * </PRE>
640 */
641APR_DECLARE(apr_status_t) apr_proc_wait(apr_proc_t *proc,
642                                        int *exitcode, apr_exit_why_e *exitwhy,
643                                        apr_wait_how_e waithow);
644
645/**
646 * Wait for any current child process to die and return information
647 * about that child.
648 * @param proc Pointer to NULL on entry, will be filled out with child's
649 *             information
650 * @param exitcode The returned exit status of the child, if a child process
651 *                 dies, or the signal that caused the child to die.
652 *                 On platforms that don't support obtaining this information,
653 *                 the status parameter will be returned as APR_ENOTIMPL.
654 * @param exitwhy Why the child died, the bitwise or of:
655 * <PRE>
656 *            APR_PROC_EXIT         -- process terminated normally
657 *            APR_PROC_SIGNAL       -- process was killed by a signal
658 *            APR_PROC_SIGNAL_CORE  -- process was killed by a signal, and
659 *                                     generated a core dump.
660 * </PRE>
661 * @param waithow How should we wait.  One of:
662 * <PRE>
663 *            APR_WAIT   -- block until the child process dies.
664 *            APR_NOWAIT -- return immediately regardless of if the
665 *                          child is dead or not.
666 * </PRE>
667 * @param p Pool to allocate child information out of.
668 * @bug Passing proc as a *proc rather than **proc was an odd choice
669 * for some platforms... this should be revisited in 1.0
670 */
671APR_DECLARE(apr_status_t) apr_proc_wait_all_procs(apr_proc_t *proc,
672                                                  int *exitcode,
673                                                  apr_exit_why_e *exitwhy,
674                                                  apr_wait_how_e waithow,
675                                                  apr_pool_t *p);
676
677#define APR_PROC_DETACH_FOREGROUND 0    /**< Do not detach */
678#define APR_PROC_DETACH_DAEMONIZE 1     /**< Detach */
679
680/**
681 * Detach the process from the controlling terminal.
682 * @param daemonize set to non-zero if the process should daemonize
683 *                  and become a background process, else it will
684 *                  stay in the foreground.
685 */
686APR_DECLARE(apr_status_t) apr_proc_detach(int daemonize);
687
688/**
689 * Register an other_child -- a child associated to its registered
690 * maintence callback.  This callback is invoked when the process
691 * dies, is disconnected or disappears.
692 * @param proc The child process to register.
693 * @param maintenance maintenance is a function that is invoked with a
694 *                    reason and the data pointer passed here.
695 * @param data Opaque context data passed to the maintenance function.
696 * @param write_fd An fd that is probed for writing.  If it is ever unwritable
697 *                 then the maintenance is invoked with reason
698 *                 OC_REASON_UNWRITABLE.
699 * @param p The pool to use for allocating memory.
700 * @bug write_fd duplicates the proc->out stream, it's really redundant
701 * and should be replaced in the APR 1.0 API with a bitflag of which
702 * proc->in/out/err handles should be health checked.
703 * @bug no platform currently tests the pipes health.
704 */
705APR_DECLARE(void) apr_proc_other_child_register(apr_proc_t *proc,
706                                           void (*maintenance) (int reason,
707                                                                void *,
708                                                                int status),
709                                           void *data, apr_file_t *write_fd,
710                                           apr_pool_t *p);
711
712/**
713 * Stop watching the specified other child.
714 * @param data The data to pass to the maintenance function.  This is
715 *             used to find the process to unregister.
716 * @warning Since this can be called by a maintenance function while we're
717 *          scanning the other_children list, all scanners should protect
718 *          themself by loading ocr->next before calling any maintenance
719 *          function.
720 */
721APR_DECLARE(void) apr_proc_other_child_unregister(void *data);
722
723/**
724 * Notify the maintenance callback of a registered other child process
725 * that application has detected an event, such as death.
726 * @param proc The process to check
727 * @param reason The reason code to pass to the maintenance function
728 * @param status The status to pass to the maintenance function
729 * @remark An example of code using this behavior;
730 * <pre>
731 * rv = apr_proc_wait_all_procs(&proc, &exitcode, &status, APR_WAIT, p);
732 * if (APR_STATUS_IS_CHILD_DONE(rv)) {
733 * \#if APR_HAS_OTHER_CHILD
734 *     if (apr_proc_other_child_alert(&proc, APR_OC_REASON_DEATH, status)
735 *             == APR_SUCCESS) {
736 *         ;  (already handled)
737 *     }
738 *     else
739 * \#endif
740 *         [... handling non-otherchild processes death ...]
741 * </pre>
742 */
743APR_DECLARE(apr_status_t) apr_proc_other_child_alert(apr_proc_t *proc,
744                                                     int reason,
745                                                     int status);
746
747/**
748 * Test one specific other child processes and invoke the maintenance callback
749 * with the appropriate reason code, if still running, or the appropriate reason
750 * code if the process is no longer healthy.
751 * @param ocr The registered other child
752 * @param reason The reason code (e.g. APR_OC_REASON_RESTART) if still running
753 */
754APR_DECLARE(void) apr_proc_other_child_refresh(apr_other_child_rec_t *ocr,
755                                               int reason);
756
757/**
758 * Test all registered other child processes and invoke the maintenance callback
759 * with the appropriate reason code, if still running, or the appropriate reason
760 * code if the process is no longer healthy.
761 * @param reason The reason code (e.g. APR_OC_REASON_RESTART) to running processes
762 */
763APR_DECLARE(void) apr_proc_other_child_refresh_all(int reason);
764
765/**
766 * Terminate a process.
767 * @param proc The process to terminate.
768 * @param sig How to kill the process.
769 */
770APR_DECLARE(apr_status_t) apr_proc_kill(apr_proc_t *proc, int sig);
771
772/**
773 * Register a process to be killed when a pool dies.
774 * @param a The pool to use to define the processes lifetime
775 * @param proc The process to register
776 * @param how How to kill the process, one of:
777 * <PRE>
778 *         APR_KILL_NEVER         -- process is never sent any signals
779 *         APR_KILL_ALWAYS        -- process is sent SIGKILL on apr_pool_t cleanup
780 *         APR_KILL_AFTER_TIMEOUT -- SIGTERM, wait 3 seconds, SIGKILL
781 *         APR_JUST_WAIT          -- wait forever for the process to complete
782 *         APR_KILL_ONLY_ONCE     -- send SIGTERM and then wait
783 * </PRE>
784 */
785APR_DECLARE(void) apr_pool_note_subprocess(apr_pool_t *a, apr_proc_t *proc,
786                                           apr_kill_conditions_e how);
787
788#if APR_HAS_THREADS
789
790#if (APR_HAVE_SIGWAIT || APR_HAVE_SIGSUSPEND) && !defined(OS2)
791
792/**
793 * Setup the process for a single thread to be used for all signal handling.
794 * @warning This must be called before any threads are created
795 */
796APR_DECLARE(apr_status_t) apr_setup_signal_thread(void);
797
798/**
799 * Make the current thread listen for signals.  This thread will loop
800 * forever, calling a provided function whenever it receives a signal.  That
801 * functions should return 1 if the signal has been handled, 0 otherwise.
802 * @param signal_handler The function to call when a signal is received
803 * apr_status_t apr_signal_thread((int)(*signal_handler)(int signum))
804 */
805APR_DECLARE(apr_status_t) apr_signal_thread(int(*signal_handler)(int signum));
806
807#endif /* (APR_HAVE_SIGWAIT || APR_HAVE_SIGSUSPEND) && !defined(OS2) */
808
809/**
810 * Get the child-pool used by the thread from the thread info.
811 * @return apr_pool_t the pool
812 */
813APR_POOL_DECLARE_ACCESSOR(thread);
814
815#endif /* APR_HAS_THREADS */
816
817/** @} */
818
819#ifdef __cplusplus
820}
821#endif
822
823#endif  /* ! APR_THREAD_PROC_H */
824
825