source: trunk/kernel/kern/process.h @ 635

Last change on this file since 635 was 635, checked in by alain, 17 months ago

This version is a major evolution: The physical memory allocators,
defined in the kmem.c, ppm.c, and kcm.c files have been modified
to support remote accesses. The RPCs that were previously user
to allocate physical memory in a remote cluster have been removed.
This has been done to cure a dead-lock in case of concurrent page-faults.

This version 2.2 has been tested on a (4 clusters / 2 cores per cluster)
TSAR architecture, for both the "sort" and the "fft" applications.

File size: 38.6 KB
Line 
1/*
2 * process.h - process related functions definition.
3 *
4 * Authors  Ghassan Almaless (2008,2009,2010,2011,2012)
5 *          Mohamed Lamine Karaoui (2015)
6 *          Alain Greiner (2016,2017,2018,2019)
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_kernel_types.h>
32#include <list.h>
33#include <xlist.h>
34#include <bits.h>
35#include <busylock.h>
36#include <rwlock.h>
37#include <queuelock.h>
38#include <remote_queuelock.h>
39#include <remote_rwlock.h>
40#include <hal_atomic.h>
41#include <vmm.h>
42#include <cluster.h>
43#include <vfs.h>
44
45/****  Forward declarations  ****/
46
47struct thread_s;
48
49/*********************************************************************************************
50 * These macros are used to compose or decompose global process identifier (PID)
51 * to or from cluster identifier / local process index (CXY , LPID)
52 ********************************************************************************************/
53
54#define LPID_FROM_PID( pid )       (lpid_t)(pid & 0x0000FFFF)
55#define CXY_FROM_PID( pid )        (cxy_t)(pid >> 16)
56#define PID( cxy , lpid )          (pid_t)((cxy << 16) | lpid )
57
58/*********************************************************************************************
59 * This enum defines the actions that can be executed by the process_sigaction() function.
60 ********************************************************************************************/
61
62typedef enum 
63{
64    BLOCK_ALL_THREADS    = 0x11,
65    UNBLOCK_ALL_THREADS  = 0x22,
66    DELETE_ALL_THREADS   = 0x33, 
67} 
68process_sigactions_t;
69
70/*********************************************************************************************
71 * This structure defines an array of extended pointers on the open file descriptors
72 * for a given process. We use an extended pointer because the open file descriptor
73 * is always stored in the same cluster as the inode associated to the file.
74 * A free entry in this array contains the XPTR_NULL value.
75 * The array size is defined by the CONFIG_PROCESS_FILE_MAX_NR parameter.
76 *
77 * NOTE: - Only the fd_array[] in the reference process contains a complete list of open
78 *         files, and is protected by the lock against concurrent access.
79 *       - the fd_array[] in a process copy is simply a cache containing a subset of the
80 *         open files to speed the fdid to xptr translation, but the "lock" and "current
81 *         fields are not used.
82 *       - all modifications made by the process_fd_remove() are done in reference cluster
83 *         and reported in all process_copies.
84 ********************************************************************************************/
85
86typedef struct fd_array_s
87{
88        remote_queuelock_t lock;                              /*! lock protecting fd_array      */
89    uint32_t           current;                           /*! current number of open files  */
90        xptr_t             array[CONFIG_PROCESS_FILE_MAX_NR]; /*! open file descriptors         */
91}
92fd_array_t;
93
94/*********************************************************************************************
95 * This structure defines a process descriptor.
96 * A process is identified by a unique PID (process identifier):
97 * - The PID 16 LSB bits contain the LPID (Local Process Index)
98 * - The PID 16 MSB bits contain the owner cluster CXY.
99 * In each cluster, the process manager allocates  the LPID values for the process that
100 * are owned by this cluster.
101 * The process descriptor is replicated in all clusters containing at least one thread
102 * of the PID process, with the following rules :
103 * 1) The <pid>, <ppid>, <ref_xp>, <owner_xp>, <vfs_root_xp>, <vfs_bin_xp>  fields are
104 *    defined in all process descriptor copies.
105 * 2) The <vfs_cwd_xp> and associated <cwd_lock>, that can be dynamically modified,
106 *    are only defined in the reference process descriptor.
107 * 2) The <vmm>, containing the VSL (list of registered vsegs), and the GPT (generic
108 *    page table), are only complete in the reference process cluster, other copies
109 *    are actually use as read-only caches.
110 * 3) the <fd_array>, containing extended pointers on the open file descriptors, is only
111 *    complete in the reference process cluster, other copies are read-only caches.
112 * 4) The <sem_root>, <mutex_root>, <barrier_root>, <condvar_root>, and the associated
113 *    <sync_lock>, dynamically allocated, are only defined in the reference cluster.
114 * 5) The <children_root>, <children_nr>, <children_list>, and <txt_list> fields are only
115 *    defined in the reference cluster, and are undefined in other clusters.
116 * 6) The <local_list>, <copies_list>, <th_tbl>, <th_nr>, <u_th_lock> or <k_th_lock> fields
117 *    are specific in each cluster, and are defined in all process descriptors copies.
118 * 7) The termination <flags> and <exit_status> are only defined in the reference cluster.
119 *    (The term_state format is defined in the shared_syscalls.h file ).
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 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             owner_xp;         /*! extended pointer on owner process               */
133    xptr_t             parent_xp;        /*! extended pointer on parent process              */
134
135        xptr_t             cwd_xp;           /*! extended pointer on current working dir inode   */
136        remote_busylock_t  cwd_lock;         /*! lock protecting working directory changes       */
137
138        xlist_entry_t      children_root;    /*! root of the children process xlist              */
139    remote_queuelock_t children_lock;    /*! lock protecting children process xlist          */
140    uint32_t           children_nr;      /*! number of children processes                    */
141
142        xlist_entry_t      children_list;    /*! member of list of children of same parent       */
143    xlist_entry_t      local_list;       /*! member of list of process in same cluster       */
144    xlist_entry_t      copies_list;      /*! member of list of copies of same process        */
145    xlist_entry_t      txt_list;         /*! member of list of processes sharing same TXT    */
146
147        struct thread_s  * th_tbl[CONFIG_THREADS_MAX_PER_CLUSTER];       /*! local threads       */
148
149        uint32_t           th_nr;            /*! number of threads in this cluster               */
150    rwlock_t           th_lock;          /*! lock protecting th_tbl[]  i                     */ 
151
152    xlist_entry_t      sem_root;         /*! root of the user defined semaphore list         */
153    xlist_entry_t      mutex_root;       /*! root of the user defined mutex list             */
154    xlist_entry_t      barrier_root;     /*! root of the user defined barrier list           */
155    xlist_entry_t      condvar_root;     /*! root of the user defined condvar list           */
156    remote_queuelock_t sync_lock;        /*! lock protecting user defined synchro lists      */
157
158    xlist_entry_t      dir_root;         /*! root of the user defined DIR list               */
159    remote_queuelock_t dir_lock;         /*! lock protexting user defined DIR list           */
160
161    uint32_t           term_state;       /*! termination status (flags & exit status)        */
162}
163process_t;
164
165/*********************************************************************************************
166 * This structure defines the information required by the process_make_exec() function
167 * to create a new reference process descriptor, and the associated main thread.
168 ********************************************************************************************/
169
170typedef struct exec_info_s
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( void );
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 contains
203 * 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 * The process GPT is initialised as required by the target architecture.
208 * The "kcode" and "kdata" segments are registered in the process VSL.
209 *********************************************************************************************
210 * @ process  : [in] pointer on process descriptor to initialize.
211 * @ info     : pointer on local boot_info_t (for kernel segments base and size).
212 ********************************************************************************************/
213void process_zero_create( process_t   * process,
214                          boot_info_t * info );
215
216/*********************************************************************************************
217 * This function allocates memory and initializes the "process_init" descriptor and the
218 * associated "thread_init" descriptor. It is called once at the end of the kernel
219 * initialisation procedure. Its local process identifier is 1, and parent process
220 * is the kernel process in cluster 0.
221 * The "process_init" is the first user process, and all other user processes will be forked
222 * from this process. The code executed by "process_init" is stored in a .elf file, whose
223 * pathname is defined by the CONFIG_PROCESS_INIT_PATH configuration variable.
224 * The process_init does not use the [STDIN/STDOUT/STDERR] streams, but it is linked
225 * to kernel TXT0, because these streams must be defined for all user processes.
226 ********************************************************************************************/
227void process_init_create( void );
228
229/*********************************************************************************************
230 * This function initializes a reference user process descriptor from another process
231 * descriptor, defined by the <parent_xp> argument. The <process> and <pid> arguments
232 * are previously allocated by the caller. This function can be called by two functions:
233 * -  process_init_create() : process is the INIT process, and parent is process-zero.
234 * -  process_make_fork()   : the parent process descriptor is generally remote.
235 * The following fields are initialised :
236 * - It set the pid / ppid / ref_xp / parent_xp / state fields.
237 * - It creates an empty GPT and an empty VSL.
238 * - It initializes the locks protecting the GPT and the VSL.
239 * - It registers the "kernel" vsegs in VSL, using the hal_vmm_kernel_update() function.
240 * - It registers the "args" and "envs" vsegs in VSL, using the vmm_user_init() function.
241 * - The "code and "data" must be registered later, using the elf_load_process() function.
242 * - It initializes the FDT, defining the three pseudo files STDIN / STDOUT / STDERR.
243 *   . if INIT process     => link to kernel TXT[0].
244 *   . if KSH[i] process   => allocate a free TXT[i].
245 *   . if USER process     => link to parent process TXT[i].
246 * - It set the root_xp, bin_xp, cwd_xp fields.
247 * - It reset the children list as empty, but does NOT register it in parent children list.
248 * - It reset the TH_TBL list of threads as empty.
249 * - It reset the semaphore / mutex / barrier / condvar lists as empty.
250 * - It registers the process in the local_list, rooted in the local cluster manager.
251 * - It registers the process in the copies_list, rooted in the owner cluster manager.
252 * - It registers the process extended pointer in the local pref_tbl[] array.
253 *********************************************************************************************
254 * @ process      : [in] pointer on local process descriptor to initialize.
255 * @ pid          : [in] process identifier.
256 * @ parent_xp    : [in] extended pointer on parent process descriptor.
257 * @ return 0 if success / return -1 if failure
258 ********************************************************************************************/
259error_t process_reference_init( process_t * process,
260                                pid_t       pid,
261                                xptr_t      parent_xp );
262
263/*********************************************************************************************
264 * This function initializes a copy process descriptor, in the local cluster,
265 * from information defined in the reference remote process descriptor.
266 * As the VSL and the GPT of a process copy are handled as local caches, the GPT copy is
267 * created empty, and the VSL copy contains only the "kernel", "args", and "envs" vsegs.
268 *********************************************************************************************
269 * @ process              : [in] local pointer on process descriptor to initialize.
270 * @ reference_process_xp : [in] extended pointer on reference process descriptor.
271 * @ return 0 if success / return -1 if failure
272 ********************************************************************************************/
273error_t process_copy_init( process_t * local_process,
274                           xptr_t      reference_process_xp );
275
276/*********************************************************************************************
277 * This function releases all memory allocated for a process descriptor in the local cluster,
278 * including memory allocated for embedded substructures (fd_array, vmm, etc).
279 * The local th_tbl[] array must be empty.
280 *********************************************************************************************
281 * @ process     : [in] pointer on the process descriptor.
282 ********************************************************************************************/
283void process_destroy( process_t * process );
284
285/*********************************************************************************************
286 * This debug function diplays on the kernel terminal TXT0 detailed informations on a
287 * process descriptor identified by the <process_xp> argument.
288 * It can be called by a thread running in any cluster.
289 * WARNING: this function uses the nolock_printk() function, and the  TXT0 lock MUST be
290 * taken by the caller function.
291 *********************************************************************************************
292 * @ process_xp    : [in] extended pointer on process descriptor.
293 ********************************************************************************************/
294void process_display( xptr_t process_xp );
295
296/*********************************************************************************************
297 * This function returns a printable string defining the sigaction type.
298 *********************************************************************************************
299 * @ sigaction_type   : BLOCK_ALL_THREADS / UNBLOCK_ALL_THREADS / DELETE_ALL_THREADS
300 * @ return a string pointer.
301 ********************************************************************************************/
302const char * process_action_str( process_sigactions_t sigaction_type );
303
304/*********************************************************************************************
305 * This function allows a client thread running in any cluster to block, unblock or delete
306 * all threads of a process identified by the <pid> argument, depending on the
307 * <action_type> argument.
308 *
309 * It uses the multicast, non blocking rpc_process_sigaction_client() function to send
310 * parallel requests to all remote clusters containing process copies.
311 * Then it blocks and deschedule to wait completion of these parallel requests.
312 *
313 * It is used by the sys_kill() & sys_exit() functions to handle the "kill" & "exit" syscalls.
314 * It is also used by the process_make_exec() function to handle the "exec" syscall.
315 * It is also called by the TXT device ISR to execute the ctrl C & ctrl Z commands.
316 *
317 * WARNING (1) the DELETE action is NOT executed on the target process main thread
318 * (thread 0 in process owner cluster), and not executed on the client thread itself.
319 *
320 * WARNING (2) the BLOCK action is executed on all target process threads, and this function
321 * returns only when all threads BUT the client thread are actually blocked and not running.
322 * When the client thread is also a target thread, it is blocked but not descheduled.
323 *
324 * WARNING (3) the UNBLOCK action is executed on all target process threads, as the
325 * client thread cannot be a target thread.
326 *
327 * Implementation note:
328 * This function allocates a - shared - RPC descriptor in client thread stack,
329 * and initializes it. This RPC descriptor can be shared because all parallel,
330 * non-blocking, RPC server threads use the same input arguments, including the
331 * RPC responses counter field.
332 *********************************************************************************************
333 * @ pid         : target process identifier.
334 * @ action_type : BLOCK_ALL_THREADS / UNBLOCK_ALL_THREADS / DELETE_ALL_THREADS
335 ********************************************************************************************/
336void process_sigaction( pid_t       pid,
337                        uint32_t    action_type );
338
339/*********************************************************************************************
340 * This function marks for delete all threads for a given <process> in the local cluster.
341 * It scan the list of local thread, and sets the THREAD_FLAG_REQ_DELETE bit for all
342 * threads, BUT the main thread (thread 0 in owner cluster), and the client thread
343 * identified by the <client_xp> argument.
344 * The actual delete will be done by the scheduler at the next scheduling point.
345 *********************************************************************************************
346 * @ process     : pointer on the process descriptor.
347 * @ client_xp   : extended pointer on the client thread that should not be marked.
348 ********************************************************************************************/
349void process_delete_threads( process_t * process,
350                             xptr_t      client_xp );
351
352/*********************************************************************************************
353 * This function blocks all threads for a given <process> in the local cluster.
354 * It scan the list of local thread, and sets the THREAD_BLOCKED_GLOBAL bit for all threads.
355 * It request the relevant schedulers to acknowledge the blocking, using IPI if required,
356 * when the target thread is running on another core than the calling thread.
357 * It returns only when all threads in cluster, including the caller are actually blocked.
358 * The threads are not detached from the scheduler, and not detached from the local process.
359 *********************************************************************************************
360 * @ process     : pointer on the target process descriptor.
361 ********************************************************************************************/
362void process_block_threads( process_t * process );
363
364/*********************************************************************************************
365 * This function unblocks all threads of a given user process in a given cluster.
366 *********************************************************************************************
367 * @ process     : pointer on the process descriptor.
368 ********************************************************************************************/
369void process_unblock_threads( process_t * process );
370
371/*********************************************************************************************
372 * This function returns a pointer on the local copy of a process identified by its PID.
373 * If this local copy does not exist yet, it is dynamically created, from the reference
374 * process descriptor, registered in the global copies_list, and registered in the local_list.
375 * This function is used by the thread_user_create() function.
376 *********************************************************************************************
377 * @ pid     : searched process identifier.
378 * @ returns pointer on the local process descriptor if success / returns NULL if failure.
379 ********************************************************************************************/
380process_t * process_get_local_copy( pid_t pid );
381
382/*********************************************************************************************
383 * This function returns the parent process identifier for a remote process descriptor
384 * identified by an extended pointer.
385 *********************************************************************************************
386 * @ process_xp   : extended pointer on remote process descriptor.
387 * @ returns parent process dentifier.
388 ********************************************************************************************/
389pid_t process_get_ppid( xptr_t process_xp );
390
391/*********************************************************************************************
392 * This function implements the "exec" system call, and is called by the sys_exec() function.
393 * The "new" process keep the "old" process PID and PPID, all open files, and env variables,
394 * the vfs_root and vfs_cwd, but build a brand new memory image (new VMM from the new .elf).
395 * It is executed in the local cluster, that becomes both the "owner" and the "reference"
396 * cluster for the "new" process.
397 *********************************************************************************************
398 * @ exec_info   : [in]  pointer on the exec_info structure.
399 * @ return 0 if success / return non-zero if error.
400 ********************************************************************************************/
401error_t process_make_exec( exec_info_t * exec_info );
402
403/*********************************************************************************************
404 * This function implements the "fork" system call, and is called by the sys_fork() function,
405 * likely through the RPC_PROCESS_MAKE_FORK.
406 * It allocates memory and initializes a new child process descriptor, and the associated
407 * child thread descriptor in local cluster. It involves up to three different clusters:
408 * - the child (local) cluster can be any cluster selected by the sys_fork function.
409 * - the parent cluster must be the reference cluster for the parent process.
410 * - the client cluster containing the thread requesting the fork can be any cluster.
411 * The new child process descriptor is initialised from informations found in the parent
412 * reference process descriptor, containing the complete process description.
413 * The new child thread descriptor is initialised from informations found in the parent
414 * thread descriptor.
415 *********************************************************************************************
416 * @ parent_process_xp  : extended pointer on the reference parent process.
417 * @ parent_thread_xp   : extended pointer on the parent thread requesting the fork.
418 * @ child_pid          : [out] child process identifier.
419 * @ child_thread_ptr   : [out] local pointer on child thread in target cluster.
420 * @ return 0 if success / return non-zero if error.
421 ********************************************************************************************/
422error_t process_make_fork(  xptr_t             parent_process_xp,
423                            xptr_t             parent_thread_xp,
424                            pid_t            * child_pid, 
425                            struct thread_s ** child_thread_ptr );
426
427
428/********************   File Management Operations   ****************************************/
429
430/*********************************************************************************************
431 * This function initializes all entries of the local fd_array as empty.
432 *********************************************************************************************
433 * @ process  : pointer on the local process descriptor.
434 ********************************************************************************************/
435void process_fd_init( process_t * process );
436
437/*********************************************************************************************
438 * This function allocates a free slot in the fd_array of the reference process
439 * identified by the <process_xp> argument, register the <file_xp> argument in the
440 * allocated slot, and return the slot index in the <fdid> buffer.
441 * It can be called by any thread in any cluster, because it uses remote access
442 * primitives to access the reference process descriptor.
443 * It takes the lock protecting the reference fd_array against concurrent accesses.
444 *********************************************************************************************
445 * @ process_xp : [in]  extended pointer on client reference process.
446 * @ file_xp    : [in]  extended pointer on the file descriptor to be registered.
447 * @ fdid       : [out] buffer for fd_array slot index.
448 * @ return 0 if success / return EMFILE if array full.
449 ********************************************************************************************/
450error_t process_fd_register( xptr_t      process_xp,
451                             xptr_t      file_xp,
452                             uint32_t  * fdid );
453
454/*********************************************************************************************
455 * This function uses as many remote accesses as required, to reset an entry in fd_array[],
456 * in all clusters containing a copy. The entry is identified by the <fdid> argument.
457 * This function must be executed by a thread running in reference cluster, that contains
458 * the complete list of process descriptors copies.
459 * It takes the lock protecting the reference fd_array against concurrent accesses.
460 * TODO this function is not implemented yet.
461 *********************************************************************************************
462 * @ process  : [in] pointer on the local process descriptor.
463 * @ fdid     : [in] file descriptor index in the fd_array.
464 ********************************************************************************************/
465void process_fd_remove( process_t * process,
466                        uint32_t    fdid );
467
468/*********************************************************************************************
469 * This function returns an extended pointer on a file descriptor identified by its index
470 * in fd_array. It can be called by any thread running in any cluster.
471 * It accesses first the local process descriptor. In case of local miss, it takes
472 * the lock protecting the reference fd_array, and access the reference process descriptor.
473 * It updates the local fd_array when the file descriptor exists in reference cluster.
474 * It takes the lock protecting the reference fd_array against concurrent accesses.
475 * The file descriptor refcount is not incremented.
476 *********************************************************************************************
477 * @ process  : pointer on the local process descriptor.
478 * @ fdid     : file descriptor index in the fd_array.
479 * @ return extended pointer on file descriptor if success / return XPTR_NULL if not found.
480 ********************************************************************************************/
481xptr_t process_fd_get_xptr( process_t * process,
482                            uint32_t    fdid );
483
484/*********************************************************************************************
485 * This function copies all non-zero entries (other than the three first stdin/stdout/stderr)
486 * from a remote <src_xp> fd_array, embedded in a process descriptor, to another remote
487 * <dst_xp> fd_array, embedded in another process descriptor.
488 * The calling thread can be running in any cluster.
489 * It takes the lock protecting the reference fd_array against concurrent accesses.
490 * For each involved file descriptor, the refcount is incremented.
491 *********************************************************************************************
492 * @ dst_xp   : extended pointer on the destination fd_array_t.
493 * @ src_xp   : extended pointer on the source fd_array_t.
494 ********************************************************************************************/
495void process_fd_remote_copy( xptr_t dst_xp,
496                             xptr_t src_xp );
497
498/*********************************************************************************************
499 * This function checks the current number of open files for a given process.
500 * It can be called by any thread in any cluster, because it uses portable remote access
501 * primitives to access the reference process descriptor.
502 * It does not take the lock protecting the reference fd_array.
503 *********************************************************************************************
504 * @ returns true if file descriptor array full.
505 ********************************************************************************************/
506bool_t process_fd_array_full( void );
507
508
509
510/********************   Thread Related Operations   *****************************************/
511
512/*********************************************************************************************
513 * This function atomically registers a new thread identified by the <thread> argument
514 * in the th_tbl[] array of the local process descriptor identified by the <process>
515 * argument. It checks that there is an available slot in the local th_tbl[] array,
516 * and allocates a new LTID using the relevant lock depending on the kernel/user type,
517 * and returns the global thread identifier in the <trdid> buffer.
518 *********************************************************************************************
519 * @ process  : [in]  pointer on the local process descriptor.
520 * @ thread   : [in]  pointer on new thread to be registered.
521 * @ trdid    : [out] buffer for allocated trdid.
522 * @ returns 0 if success / returns non zero if no slot available.
523 ********************************************************************************************/
524error_t process_register_thread( process_t       * process,
525                                 struct thread_s * thread,
526                                 trdid_t         * trdid );
527
528/*********************************************************************************************
529 * This function atomically removes a thread identified by the <thread> argument from
530 * the local process descriptor th_tbl[] array, and returns the number of thread currently
531 * registered in th_tbl[] array before this remove.
532 *********************************************************************************************
533 * @ thread   : pointer on thread to be removed.
534 * @ returns number of threads registered in th_tbl before thread remove.
535 ********************************************************************************************/
536uint32_t process_remove_thread( struct thread_s * thread );
537
538
539/***************   Terminals related operations  ********************************************/
540
541/*********************************************************************************************
542 * This function scan the set of user TXT terminals to find a free terminal
543 * (the list of attached processes is empty for a free TXT terminal).
544 * It is called only by the process_reference_init() function when creating a KSH process.
545 * It makes a kernel panic if no free TXT terminal is found.
546 * The allocated TXT terminal is only released when the KSH process is deleted.
547 *********************************************************************************************
548 * @ return TXT terminal index if succes / kernel panic if no terminal found.
549 ********************************************************************************************/
550uint32_t process_txt_alloc( void );
551
552/*********************************************************************************************
553 * This function attach a process, identified by the <process> argument to a TXT terminal,
554 * identified by the <txt_id> channel index argument.
555 * The process descriptor identified by the <process> argument must be in the owner cluster. 
556 * It insert the process descriptor in the xlist rooted in the TXT_RX device.
557 * It is called by the process_reference_init() function.
558 *********************************************************************************************
559 * @ process  : local pointer on process descriptor.
560 * @ txt_id   : TXT channel index.
561 ********************************************************************************************/
562void process_txt_attach( process_t * process,
563                         uint32_t    txt_id );
564
565/*********************************************************************************************
566 * This function detach a process, identified by the <process_xp> argument,
567 * from the list of process attached to a given TXT terminal. It transfer the TXT ownership
568 * to another process, if the detached process is the TXT owner.
569 * The process descriptor identified by the <process_xp> argument must be in the owner
570 * cluster, but the calling thread can be running in any cluster.
571 *********************************************************************************************
572 * @ process_xp  : extended pointer on process descriptor.
573 ********************************************************************************************/
574void process_txt_detach( xptr_t  process_xp );                     
575
576/*********************************************************************************************
577 * This function gives a process identified by the <process_xp> argument the
578 * ownership of its attached TXT_RX terminal (i.e. put the process in foreground).
579 * It can be called by a thread running in any cluster, but the target process descriptor
580 * must be the process owner.
581 *********************************************************************************************
582 * @ owner_xp  : extended pointer on process descriptor in owner cluster.
583 ********************************************************************************************/
584void process_txt_set_ownership( xptr_t process_xp );
585
586/*********************************************************************************************
587 * When the target process identified by the <owner_xp> argument has the exclusive ownership
588 * of the TXT_RX terminal, this function transfer this ownership to another process attached
589 * to the same terminal. The target process descriptor must be the process owner.
590 * This function does nothing if the target process is not the TXT owner.
591 * - If the current owner is not the KSH process, the new owner is the KSH process.
592 * - If the current owner is the KSH process, the new owner is another attached process.
593 * - If there is no other attached process, the TXT has no more defined owner.
594 *********************************************************************************************
595 * @ process_xp  : extended pointer on process descriptor in owner cluster.
596 ********************************************************************************************/
597void process_txt_transfer_ownership( xptr_t process_xp );
598
599/*********************************************************************************************
600 * This function returns true if the  process identified by the <process_xp> argument
601 * is the TXT owner. It can be called by a thread running in any cluster, but the
602 * process_xp must be the owner cluster process descriptor.
603 *********************************************************************************************
604 * @ returns true if target process is TXT owner.
605 ********************************************************************************************/
606bool_t process_txt_is_owner( xptr_t process_xp );
607
608/*********************************************************************************************
609 * This function returns an extended ponter on the current TXT owner process,
610 * for the TXT terminal identified by the <channel> index.
611 *********************************************************************************************
612 * @ channel : TXT channel.
613 * @ return extended pointer on TXT owner process.
614 ********************************************************************************************/
615xptr_t process_txt_get_owner( uint32_t channel );
616
617/*********************************************************************************************
618 * This debug function diplays on the kernel terminal the list of processes attached
619 * to a given terminal identified by the <txt_id> argument.
620 *********************************************************************************************
621 * @ txt_id  : TXT terminal channel.
622 ********************************************************************************************/
623void process_txt_display( uint32_t txt_id );
624
625
626#endif  /* _PROCESS_H_ */
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