source: trunk/kernel/kern/process.h@ 428

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1/*
2 * process.h - process related management functions
3 *
4 * Authors Ghassan Almaless (2008,2009,2010,2011,2012)
5 * Mohamed Lamine Karaoui (2015)
6 * Alain Greiner (2016,2017)
7 *
8 * Copyright (c) UPMC Sorbonne Universites
9 *
10 * This file is part of ALMOS-MKH.
11 *
12 * ALMOS-MKH is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; version 2.0 of the License.
15 *
16 * ALMOS-MKH is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
23 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
24 */
25
26#ifndef _PROCESS_H_
27#define _PROCESS_H_
28
29#include <kernel_config.h>
30#include <errno.h>
31#include <hal_types.h>
32#include <list.h>
33#include <xlist.h>
34#include <bits.h>
35#include <spinlock.h>
36#include <hal_atomic.h>
37#include <vmm.h>
38#include <signal.h>
39#include <cluster.h>
40#include <vfs.h>
41
42/**** Forward declarations ****/
43
44struct thread_s;
45
46/*********************************************************************************************
47 * These macros are used to compose or decompose global process identifier (PID)
48 * to or from cluster identifier / local process index (CXY , LPID)
49 ********************************************************************************************/
50
51#define LPID_FROM_PID( pid ) (lpid_t)(pid & 0x0000FFFF)
52#define CXY_FROM_PID( pid ) (cxy_t)(pid >> 16)
53#define PID( cxy , lpid ) (pid_t)((cxy << 16) | lpid )
54
55/*********************************************************************************************
56 * This enum defines the actions that can be executed by the process_sigaction() function.
57 ********************************************************************************************/
58
59enum process_sigactions
60{
61 BLOCK_ALL_THREADS = 11,
62 UNBLOCK_ALL_THREADS = 22,
63 DELETE_ALL_THREADS = 33,
64};
65
66/*********************************************************************************************
67 * This enum defines the process states for ALMOS_MKH.
68 ********************************************************************************************/
69
70enum process_states
71{
72 PROCESS_STATE_RUNNING = 0, /*! process is executing */
73 PROCESS_STATE_STOPPED = 1, /*! process has been stopped by a signal */
74 PROCESS_STATE_KILLED = 2, /*! process has been killed by a signal */
75 PROCESS_STATE_EXITED = 3, /*! process terminated with an exit */
76};
77
78/*********************************************************************************************
79 * This structure defines an array of extended pointers on the open file descriptors
80 * for a given process. We use an extended pointer because the open file descriptor
81 * is always stored in the same cluster as the inode associated to the file.
82 * A free entry in this array contains the XPTR_NULL value.
83 * The array size is defined by a the CONFIG_PROCESS_FILE_MAX_NR parameter.
84 * All modifications (open/close) in this structure must be done by the reference cluster,
85 * and reported in process copies.
86 ********************************************************************************************/
87
88typedef struct fd_array_s
89{
90 remote_spinlock_t lock; /*! lock protecting fd_array */
91 uint32_t current; /*! current number of open files */
92 xptr_t array[CONFIG_PROCESS_FILE_MAX_NR]; /*! xptr on open file descriptors */
93}
94fd_array_t;
95
96/*********************************************************************************************
97 * This structure defines a process descriptor.
98 * A process is identified by a unique PID (process identifier):
99 * - The PID 16 LSB bits contain the LPID (Local Process Index)
100 * - The PID 16 MSB bits contain the owner cluster CXY.
101 * In each cluster, the process manager allocates the LPID values for the process that
102 * are owned by this cluster.
103 * The process descriptor is replicated in all clusters containing at least one thread
104 * of the PID process, with the following rules :
105 * 1) The <pid>, <ppid>, <ref_xp>, <vfs_root_xp>, <vfs_bin_xp> fields are defined
106 * in all process descriptor copies.
107 * 2) The <vfs_cwd_xp> and associated <cwd_lock>, that can be dynamically modified,
108 * are only defined in the reference process descriptor.
109 * 2) The <vmm>, containing the VSL (list of registered vsegs), and the GPT (generic
110 * page table), are only complete in the reference process cluster, other copies
111 * are actually use as read-only caches.
112 * 3) the <fd_array>, containing extended pointers on the open file descriptors, is only
113 * complete in the reference process cluster, other copies are read-only caches.
114 * 4) The <sem_root>, <mutex_root>, <barrier_root>, <condvar_root>, and the associated
115 * <sync_lock>, that are dynamically allocated, are only defined in the reference cluster.
116 * 5) The <children_root>, <children_nr>, <brothers_list>, and <txt_list> fields are only
117 * defined in the reference cluster, and are undefined in other clusters.
118 * 6) The <local_list>, <copies_list>, <th_tbl>, <th_nr>, <th_lock> fields
119 * are defined in all process descriptors copies.
120 ********************************************************************************************/
121
122typedef struct process_s
123{
124 vmm_t vmm; /*! embedded virtual memory manager */
125
126 fd_array_t fd_array; /*! embedded open file descriptors array */
127
128 xptr_t vfs_root_xp; /*! extended pointer on current VFS root inode */
129 xptr_t vfs_bin_xp; /*! extended pointer on .elf file descriptor */
130 pid_t pid; /*! process identifier */
131 xptr_t ref_xp; /*! extended pointer on reference process */
132 xptr_t parent_xp; /*! extended pointer on parent process */
133
134 xptr_t vfs_cwd_xp; /*! extended pointer on current working dir inode */
135 remote_rwlock_t cwd_lock; /*! lock protecting working directory changes */
136
137 xlist_entry_t children_root; /*! root of the children process xlist */
138 remote_spinlock_t children_lock; /*! lock protecting children process xlist */
139 uint32_t children_nr; /*! number of children processes */
140
141 xlist_entry_t children_list; /*! member of list of children of same parent */
142 xlist_entry_t local_list; /*! member of list of process in same cluster */
143 xlist_entry_t copies_list; /*! member of list of copies of same process */
144 xlist_entry_t txt_list; /*! member of list of processes sharing same TXT */
145
146 spinlock_t th_lock; /*! lock protecting th_tbl[] concurrent access */
147 uint32_t th_nr; /*! number of threads in this cluster */
148
149 struct thread_s * th_tbl[CONFIG_THREAD_MAX_PER_CLUSTER]; /*! pointers on local threads */
150
151 xlist_entry_t sem_root; /*! root of the process semaphore list */
152 xlist_entry_t mutex_root; /*! root of the process mutex list */
153 xlist_entry_t barrier_root; /*! root of the process barrier list */
154 xlist_entry_t condvar_root; /*! root of the process condvar list */
155 remote_spinlock_t sync_lock; /*! lock protecting sem,mutex,barrier,condvar lists */
156
157 uint32_t state; /*! RUNNING / STOPPED / KILLED / EXITED */
158
159 bool_t txt_owner; /*! current TXT owner */
160}
161process_t;
162
163/*********************************************************************************************
164 * This structure defines the information required by the process_make_exec() function
165 * to create a new reference process descriptor, and the associated main thread.
166 ********************************************************************************************/
167
168typedef struct exec_info_s
169{
170 pid_t pid; /*! process identifier (both parent and child) */
171
172 char path[CONFIG_VFS_MAX_PATH_LENGTH]; /*! .elf file path */
173
174 char ** args_pointers; /*! physical base address of array of pointers */
175 char * args_buf_base; /*! physical base address of kernel args buffer */
176 uint32_t args_nr; /*! actual number of arguments */
177
178 char ** envs_pointers; /*! physical base address of array of pointers */
179 char * envs_buf_base; /*! physical base address of kernel args buffer */
180 char * envs_buf_free; /*! physical address of first free slot in envs_buf */
181 uint32_t envs_nr; /*! actual number of environment variables */
182}
183exec_info_t;
184
185/*************** Process Descriptor Operations *****************************************/
186
187/*********************************************************************************************
188 * This function allocates memory in local cluster for a process descriptor.
189 *********************************************************************************************
190 * @ returns pointer on process descriptor if success / return NULL if failure
191 ********************************************************************************************/
192process_t * process_alloc();
193
194/*********************************************************************************************
195 * This function releases memory in local cluster for a process descriptor.
196 *********************************************************************************************
197 * @ process : pointer on process descriptor to release.
198 ********************************************************************************************/
199void process_free( process_t * process );
200
201/*********************************************************************************************
202 * This function initialize, in each cluster, the kernel "process_zero", that is the owner
203 * of all kernel threads in a given cluster. It is called by the kernel_init() function.
204 * The process_zero descriptor is allocated as a global variable in file kernel_init.c
205 * Both the PID and PPID fields are set to zero, the ref_xp is the local process_zero,
206 * and the parent process is set to XPTR_NULL. The th_tbl[] is initialized as empty.
207 *********************************************************************************************
208 * @ process : [in] pointer on local process descriptor to initialize.
209 ********************************************************************************************/
210void process_zero_create( process_t * process );
211
212/*********************************************************************************************
213 * This function allocates memory and initializes the "process_init" descriptor and the
214 * associated "thread_init" descriptor. It is called once at the end of the kernel
215 * initialisation procedure. Its local process identifier is 1, and parent process
216 * is the kernel process in cluster 0.
217 * The "process_init" is the first user process, and all other user processes will be forked
218 * from this process. The code executed by "process_init" is stored in a .elf file, whose
219 * pathname is defined by the CONFIG_PROCESS_INIT_PATH configuration variable.
220 * The process_init does not use the [STDIN/STDOUT/STDERR] streams, but it is linked
221 * to kernel TXT0, because these streams must be defined for all user processes.
222 ********************************************************************************************/
223void process_init_create();
224
225/*********************************************************************************************
226 * This function initializes a local, reference, user process descriptor from another process
227 * descriptor, defined by the <model_xp> argument. The <process> and <pid> arguments must
228 * be previously allocated by he caller. This function can be called by three functions:
229 * 1) process_init_create() : process is the reference INIT process / pid = 1 /
230 * the parent and model process descriptors are both the kernel process_zero.
231 * 2) process_make_fork() : the model process descriptor is the (generally remote)
232 * parent process.
233 * 3) process_make exec() : the model process is the local old_process, the new_process
234 * parent is the same as the old_process parent.
235 * The following fields are initialised :
236 * - It set the pid / ppid / ref_xp / parent_xp / state fields.
237 * - It initializes the VMM (register the kentry, args, envs vsegs in VSL)
238 * - It initializes the FDT, defining the three pseudo files STDIN / STDOUT / STDERR.
239 * - It set the root_xp, bin_xp, cwd_xp fields.
240 * - It reset the children list as empty, but does NOT register it in parent children list.
241 * - It reset the TH_TBL list of threads as empty.
242 * - It reset the semaphore / mutex / barrier / condvar lists as empty.
243 * - It registers the process in the local_list, rooted in the local cluster manager.
244 * - It registers the process in the copies_list, rooted in the owner cluster manager.
245 * - It registers the process extended pointer in the local pref_tbl[] array.
246 *********************************************************************************************
247 * @ process : [in] pointer on local process descriptor to initialize.
248 * @ pid : [in] process identifier.
249 * @ parent_xp : [in] extended pointer on parent process descriptor.
250 * @ model_xp : [in] extended pointer on model process descriptor.
251 ********************************************************************************************/
252void process_reference_init( process_t * process,
253 pid_t pid,
254 xptr_t parent_xp,
255 xptr_t model_xp );
256
257/*********************************************************************************************
258 * This function initializes a copy process descriptor, in the local cluster,
259 * from information defined in the reference remote process descriptor.
260 *********************************************************************************************
261 * @ process : [in] local pointer on process descriptor to initialize.
262 * @ reference_process_xp : [in] extended pointer on reference process descriptor.
263 * @ return 0 if success / return ENOMEM if failure
264 ********************************************************************************************/
265error_t process_copy_init( process_t * local_process,
266 xptr_t reference_process_xp );
267
268/*********************************************************************************************
269 * This function releases all memory allocated for a process descriptor in the local cluster,
270 * including memory allocated for embedded substructures (fd_array, vmm, etc).
271 * The local th_tbl[] array must be empty.
272 *********************************************************************************************
273 * @ process : pointer on the process descriptor.
274 ********************************************************************************************/
275void process_destroy( process_t * process );
276
277/*********************************************************************************************
278 * This function returns a printable string defining the process state.
279 *********************************************************************************************
280 * @ state : RUNNING / BLOCKED / EXITED / KILLED
281 * @ return a string pointer.
282 ********************************************************************************************/
283char * process_state_str( uint32_t state );
284
285/*********************************************************************************************
286 * This debug function diplays on the kernel terminal TXT0 detailed informations on a
287 * reference process identified by the <process_xp> argument.
288 * It can be called by a thread running in any cluster.
289 *********************************************************************************************
290 * @ process_xp : extended pointer on reference process.
291 ********************************************************************************************/
292void process_display( xptr_t process_xp );
293
294/*********************************************************************************************
295 * This function returns a printable string defining the sigaction type.
296 *********************************************************************************************
297 * @ sigaction_type : BLOCK_ALL_THREADS / UNBLOCK_ALL_THREADS / DELETE_ALL_THREADS
298 * @ return a string pointer.
299 ********************************************************************************************/
300char * process_action_str( uint32_t sigaction_type );
301
302/*********************************************************************************************
303 * This function allows a client thread running in the owner cluster of a process identified
304 * by the <process> argument to block, unblock or delete all threads of the target process,
305 * depending on the <action_type> argument. The scenario is the following:
306 * - It uses the multicast, non blocking rpc_process_sigaction_client() function to send
307 * parallel requests to all remote clusters containing a process copy. Then it blocks
308 $ and deschedule to wait completion of these parrallel requests.
309 * - In each remote cluster, the rpc_process_sigaction_server() function, calls directly
310 * the relevant process_block(), process_unblock(), or process_delete() function, and
311 * decrement the responses counter to signal completion. The last server unblock
312 * the client thread.
313 * - Finally, the client thread calls directly the process_block(), process_unblock(), or
314 * process_delete() function in the owner cluster.
315 * It is used by the sys_kill() & sys_exit() functions to handle the "kill" & "exit" syscalls.
316 * It is also used by the process_make_exec() function to handle the "exec" syscall.
317 * WARNING : the DELETE and the BLOCK actions are NOT executed on the client thread.
318 *********************************************************************************************
319 * @ process : pointer on the process descriptor in owner cluster.
320 * @ action_type : BLOCK_ALL_THREADS / UNBLOCK_ALL_THREADS / DELETE_ALL_THREADS
321 ********************************************************************************************/
322void process_sigaction( process_t * process,
323 uint32_t action_type );
324
325/*********************************************************************************************
326 * This function blocks all threads (but the client thread defined by the <client_xp>
327 * argument) for a given <process> in a given cluster.
328 * It loops on all local threads of the process, set the THREAD_BLOCKED_GLOBAL bit,
329 * and request the relevant schedulers to acknowledge the blocking, using IPI if required.
330 * The threads are not detached from the scheduler, and not detached from the local process.
331 * This function returns only when all blockable threads in cluster are actually blocked.
332 *********************************************************************************************
333 * @ process : pointer on the target process descriptor.
334 * @ client_xp : extended pointer on the client thread, that should not be blocked.
335 ********************************************************************************************/
336void process_block_threads( process_t * process,
337 xptr_t client_xp );
338
339/*********************************************************************************************
340 * This function unblocks all threads of a given user process in a given cluster.
341 *********************************************************************************************
342 * @ process : pointer on the process descriptor.
343 ********************************************************************************************/
344void process_unblock_threads( process_t * process );
345
346/*********************************************************************************************
347 * This function delete all threads, (but the client thread defined by the <client_xp>
348 * argument) for a given <process> in a given cluster.
349 * It loops on all local threads of the process, and set the THREAD_FLAG_REQ_DELETE bit.
350 * For each marked thread, the following actions will be done by the scheduler at the next
351 * scheduling point:
352 * - the thread will be detached from the scheduler.
353 * - the thread will be detached from the local process descriptor.
354 * - the thread will be detached from parent if required.
355 * - the memory allocated to the thread descriptor is released.
356 * - the memory allocated to the process descriptor is released, if it is the last thread.
357 *********************************************************************************************
358 * @ process : pointer on the process descriptor.
359 * @ client_xp : extended pointer on the client thread, that should not be deleted.
360 ********************************************************************************************/
361void process_delete_threads( process_t * process,
362 xptr_t client_xp );
363
364/*********************************************************************************************
365 * This function returns a pointer on the local copy of a process identified by its PID.
366 * If this local copy does not exist yet, it is dynamically created, from the reference
367 * process descriptor, registered in the global copies_list, and registered in the local_list.
368 * This function is used by the thread_user_create() function.
369 *********************************************************************************************
370 * @ pid : searched process identifier.
371 * @ returns pointer on the local process descriptor if success / returns NULL if failure.
372 ********************************************************************************************/
373process_t * process_get_local_copy( pid_t pid );
374
375/*********************************************************************************************
376 * This function implements the "exec" system call, and is called by the sys_exec() function.
377 * The "new" process keep the "old" process PID and PPID, all open files, and env variables,
378 * the vfs_root and vfs_cwd, but build a brand new memory image (new VMM from the new .elf).
379 * It actually creates a "new" reference process descriptor, and copies all relevant
380 * information from the "old" process descriptor to the "new" process descriptor.
381 * It completes the "new" process descriptor, from information found in the <exec_info>
382 * structure (defined in the process.h file), that must be built by the caller.
383 * It creates and initializes the associated main thread. It finally destroys all copies
384 * of the "old" process in all clusters, and destroys all old associated threads.
385 * It is executed in the local cluster, that becomes both the "owner" and the "reference"
386 * cluster for the "new" process.
387 *********************************************************************************************
388 * @ exec_info : [in] pointer on the exec_info structure.
389 * @ return 0 if success / return non-zero if error.
390 ********************************************************************************************/
391error_t process_make_exec( exec_info_t * exec_info );
392
393/*********************************************************************************************
394 * This function implements the "fork" system call, and is called by the sys_fork() function.
395 * It allocates memory and initializes a new "child" process descriptor, and the
396 * associated "child" thread descriptor in the local cluster. This function can involve
397 * up to three different clusters :
398 * - the local (child) cluster can be any cluster defined by the sys_fork function.
399 * - the parent cluster must be the reference cluster for the parent process.
400 * - the client cluster containing the thread requesting the fork can be any cluster.
401 * The new "child" process descriptor is initialised from informations found in the "parent"
402 * reference process descriptor, containing the complete process description.
403 * The new "child" thread descriptor is initialised from informations found in the "parent"
404 * thread descriptor.
405 *********************************************************************************************
406 * @ parent_process_xp : extended pointer on the reference parent process.
407 * @ parent_thread_xp : extended pointer on the parent thread requesting the fork.
408 * @ child_pid : [out] child process identifier.
409 * @ child_thread_ptr : [out] local pointer on child thread in target cluster.
410 * @ return 0 if success / return non-zero if error.
411 ********************************************************************************************/
412error_t process_make_fork( xptr_t parent_process_xp,
413 xptr_t parent_thread_xp,
414 pid_t * child_pid,
415 struct thread_s ** child_thread_ptr );
416
417/*********************************************************************************************
418 * This function implement the "exit" system call, and is called by the sys_exit() function.
419 * It must be executed by a thread running in the calling process owner cluster.
420 * It uses twice the multicast RPC_PROCESS_SIGNAL to first block all process threads
421 * in all clusters, and then delete all threads and process descriptors.
422 *********************************************************************************************
423 * @ pid : process identifier.
424 * @ status : exit return value.
425 ********************************************************************************************/
426void process_make_exit( pid_t pid,
427 uint32_t status );
428
429/*********************************************************************************************
430 * This function implement the "kill" system call, and is called by the sys_kill() function.
431 * It must be executed by a thread running in the target process owner cluster.
432 * Only the SIGKILL, SIGSTOP, and SIGCONT signals are supported.
433 * User defined handlers are not supported.
434 * It uses once or twice the multicast RPC_PROCESS_SIGNAL to block, unblock or delete
435 * all process threads in all clusters, and then delete process descriptors.
436 *********************************************************************************************
437 * @ pid : process identifier.
438 * @ sig_id : signal type.
439 ********************************************************************************************/
440void process_make_kill( pid_t pid,
441 uint32_t sig_id );
442
443
444/******************** File Management Operations ****************************************/
445
446/*********************************************************************************************
447 * This function initializes all entries of the local fd_array as empty.
448 *********************************************************************************************
449 * @ process : pointer on the local process descriptor.
450 ********************************************************************************************/
451void process_fd_init( process_t * process );
452
453/*********************************************************************************************
454 * This function uses as many remote accesses as required, to reset an entry in fd_array[],
455 * in all clusters containing a copy. The entry is identified by the <fdid> argument.
456 * This function must be executed by a thread running reference cluster, that contains
457 * the complete list of process descriptors copies.
458 *********************************************************************************************
459 * @ process : pointer on the local process descriptor.
460 * @ fdid : file descriptor index in the fd_array.
461 ********************************************************************************************/
462void process_fd_remove( process_t * process,
463 uint32_t fdid );
464
465/*********************************************************************************************
466 * This function returns an extended pointer on a file descriptor identified by its index
467 * in fd_array. It can be called by any thread running in any cluster.
468 * It accesses first the local process descriptor. In case of local miss, it uses remote
469 * access to access the reference process descriptor.
470 * It updates the local fd_array when the file descriptor exists in reference cluster.
471 * The file descriptor refcount is not incremented.
472 *********************************************************************************************
473 * @ process : pointer on the local process descriptor.
474 * @ fdid : file descriptor index in the fd_array.
475 * @ return extended pointer on file descriptor if success / return XPTR_NULL if not found.
476 ********************************************************************************************/
477xptr_t process_fd_get_xptr( process_t * process,
478 uint32_t fdid );
479
480/*********************************************************************************************
481 * This function checks the number of open files for a given process.
482 * It can be called by any thread in any cluster, because it uses portable remote access
483 * primitives to access the reference process descriptor.
484 *********************************************************************************************
485 * @ returns true if file descriptor array full.
486 ********************************************************************************************/
487bool_t process_fd_array_full();
488
489/*********************************************************************************************
490 * This function allocates a free slot in the fd_array of the reference process,
491 * register the <file_xp> argument in the allocated slot, and return the slot index.
492 * It can be called by any thread in any cluster, because it uses portable remote access
493 * primitives to access the reference process descriptor.
494 *********************************************************************************************
495 * @ file_xp : extended pointer on the file descriptor to be registered.
496 * @ fdid : [out] buffer for fd_array slot index.
497 * @ return 0 if success / return EMFILE if array full.
498 ********************************************************************************************/
499error_t process_fd_register( process_t * process,
500 xptr_t file_xp,
501 uint32_t * fdid );
502
503/*********************************************************************************************
504 * This function copies all non-zero entries (other than the three first stdin/stdout/stderr)
505 * from a remote <src_xp> fd_array, embedded in a process descriptor, to another remote
506 * <dst_xp> fd_array, embedded in another process descriptor.
507 * The calling thread can be running in any cluster.
508 * It takes the remote lock protecting the <src_xp> fd_array during the copy.
509 * For each involved file descriptor, the refcount is incremented.
510 *********************************************************************************************
511 * @ dst_xp : extended pointer on the destination fd_array_t.
512 * @ src_xp : extended pointer on the source fd_array_t.
513 ********************************************************************************************/
514void process_fd_remote_copy( xptr_t dst_xp,
515 xptr_t src_xp );
516
517
518
519/******************** Thread Related Operations *****************************************/
520
521/*********************************************************************************************
522 * This function registers a new thread in the local process descriptor.
523 * It checks that there is an available slot in the local th_tbl[] array,
524 * allocates a new LTID, and registers the new thread in the th_tbl[].
525 * WARNING : the lock protecting the th_tbl[] must be taken by the caller.
526 *********************************************************************************************
527 * @ process : pointer on the local process descriptor.
528 * @ thread : pointer on new thread to be registered.
529 * @ trdid : [out] address of buffer for allocated trdid.
530 * @ returns 0 if success / returns non zero if no slot available.
531 ********************************************************************************************/
532error_t process_register_thread( process_t * process,
533 struct thread_s * thread,
534 trdid_t * trdid );
535
536/*********************************************************************************************
537 * This function removes a thread registration from the local process descriptor.
538 * WARNING : the lock protecting the th_tbl[] must be taken by the caller.
539 *********************************************************************************************
540 * @ thread : local pointer on thread to be removed.
541 ********************************************************************************************/
542void process_remove_thread( struct thread_s * thread );
543
544
545/*************** Terminals related operations ********************************************/
546
547/*********************************************************************************************
548 * This function scan the set of user TXT terminals to find a free terminal
549 * (the list of attached processes is empty for a free TXT terminal).
550 * It is called only by the process_reference_init() function when creating a KSH process.
551 * It makes a kernel panic if no free TXT terminal is found.
552 * As a KSH process is never deleted, the allocated TXT terminal is never released.
553 *********************************************************************************************
554 * @ return TXT terminal index if succes / kernel panic if no terminal found.
555 ********************************************************************************************/
556uint32_t process_txt_alloc();
557
558/*********************************************************************************************
559 * This function attach a reference process descriptor, identified by the <process>
560 * argument to a TXT terminal, identified by its <txt_id> channel index argument.
561 * It insert the process descriptor in the xlist rooted in the TXT_RX device.
562 * It is called by the process_reference_init() function.
563 *********************************************************************************************
564 * @ process : local pointer on process descriptor.
565 * @ txt_id : TXT channel index.
566 ********************************************************************************************/
567void process_txt_attach( process_t * process,
568 uint32_t txt_id );
569
570/*********************************************************************************************
571 * This function detach a reference process descriptor, identified by the <process_xp>
572 * argument, from the list of process attached to a given TXT terminal.
573 * It is called when the process is killed.
574 *********************************************************************************************
575 * @ process : local pointer on process descriptor.
576 ********************************************************************************************/
577void process_txt_detach( process_t * process );
578
579/*********************************************************************************************
580 * This function gives to a process identified by the <process_xp> argument, and attached
581 * to terminal TXT[i] the exclusive ownership of the TXT_RX[i] terminal.
582 *********************************************************************************************
583 * @ process_xp : extended pointer on reference process descriptor.
584 ********************************************************************************************/
585void process_txt_set_ownership( xptr_t process_xp );
586
587/*********************************************************************************************
588 * When the process identified by the <process_xp> argument has the exclusive ownership
589 * of the TXT_RX[i] terminal, this function gives this ownership to the KSH[i] process.
590 * It does nothing if the process is not the owner.
591 *********************************************************************************************
592 * @ process_xp : extended pointer on reference process descriptor.
593 ********************************************************************************************/
594void process_txt_reset_ownership( xptr_t process_xp );
595
596#endif /* _PROCESS_H_ */
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