source: trunk/kernel/kern/process.h @ 176

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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 structure defines an array of extended pointers on the open file descriptors
57 * for a given process. We use an extended pointer because the open file descriptor
58 * is always stored in the same cluster as the inode associated to the file.
59 * A free entry in this array contains the XPTR_NULL value.
60 * The array size is defined by a the CONFIG_PROCESS_FILE_MAX_NR parameter.
61 * All modifications (open/close) in this structure must be done by the reference cluster,
62 * and reported in process copies.
63 ********************************************************************************************/
64
65typedef struct fd_array_s
66{
67        remote_spinlock_t lock;                               /*! lock protecting fd_array      */
68    uint32_t          current;                            /*! current number of open files  */
69        xptr_t            array[CONFIG_PROCESS_FILE_MAX_NR];  /*! xptr on open file descriptors */
70}
71fd_array_t;
72
73/*********************************************************************************************
74 * This structure defines a process descriptor.
75 * A process is identified by a unique PID (process identifier):
76 * - The PID 16 LSB bits contain the LPID (Local Process Index)
77 * - The PID 16 MSB bits contain the owner cluster CXY.
78 * In each cluster, the process manager allocates LPID values for the process that are
79 * allocated to this cluster.
80 * The process descriptor for a PID process is replicated in all clusters containing
81 * at least one thread of the PID process, with the following rules :
82 *
83 * 1) The <pid>, <ppid>, <ref_xp>, <vfs_root_xp>, <vfs_bin_xp>  fields are defined
84 *    in all process descriptor copies.
85 * 2) The <vfs_cwd_xp> and associated <cwd_lock>, that can be dynamically modified,
86 *    are only defined in the reference process descriptor.
87 * 2) The <vmm>, containing the list of registered vsegs, and the page table, are only
88 *    complete in the reference process cluster, other copies are read-only caches.
89 * 3) the <fd_array>, containing extended pointers on the open file descriptors, is only
90 *    complete in the reference process cluster, other copies are read-only caches.
91 * 4) The <sem_root>, <mutex_root>, <barrier_root>, <condvar_root>, and the associated
92 *    <sync_lock>, that are dynamically allocated, are only defined in the reference cluster.
93 * 5) The <children_root>, and <children_nr> fields are only defined in the reference
94 *    cluster, and are undefined in other clusters.
95 * 6) The <brothers_list>, <local_list>, <copies_list>, <th_tbl>, <th_nr>, <th_lock> fields
96 *    are defined in all process descriptors copies.
97 * 7) The <sig_mgr> field is only defined in the reference cluster. TODO
98 ********************************************************************************************/
99
100typedef struct process_s
101{
102        vmm_t             vmm;              /*! embedded virtual memory manager                 */
103
104        fd_array_t        fd_array;         /*! embedded open file descriptors array            */
105
106        xptr_t            vfs_root_xp;      /*! extended pointer on current VFS root inode      */
107        xptr_t            vfs_bin_xp;       /*! extended pointer on .elf file inode             */
108        pid_t             pid;              /*! process identifier                              */
109        pid_t             ppid;             /*! parent process identifier                       */
110    xptr_t            ref_xp;           /*! extended pointer on reference process           */
111
112        xptr_t            vfs_cwd_xp;       /*! extended pointer on current working dir inode   */
113        remote_rwlock_t   cwd_lock;         /*! lock protecting working directory changes       */
114
115        xlist_entry_t     children_root;    /*! root of the children process xlist              */
116    uint32_t          children_nr;      /*! number of children processes                    */
117
118        xlist_entry_t     brothers_list;    /*! member of list of children of same parent       */
119    xlist_entry_t     local_list;       /*! member of list of process in same cluster       */
120    xlist_entry_t     copies_list;      /*! member of list of copies of same process        */
121
122        spinlock_t        th_lock;          /*! lock protecting th_tbl[] concurrent access      */
123        uint32_t          th_nr;            /*! number of threads in this cluster               */
124        struct thread_s * th_tbl[CONFIG_THREAD_MAX_PER_CLUSTER]; /*! pointers on local threads  */
125
126    xlist_entry_t     sem_root;         /*! root of the process semaphore list              */
127    xlist_entry_t     mutex_root;       /*! root of the process mutex list                  */
128    xlist_entry_t     barrier_root;     /*! root of the process barrier list                */
129    xlist_entry_t     condvar_root;     /*! root of the process condvar list                */
130
131    remote_spinlock_t sync_lock;        /*! lock protecting sem,mutex,barrier,condvar lists */
132
133        sig_mgr_t         sig_mgr;          /*! embedded signal manager TODO [AG]               */
134}
135process_t;
136
137/*********************************************************************************************
138 * This structure defines the information required by the process_make_exec() function
139 * to create a new reference process descriptor, and the associated main thread.
140 ********************************************************************************************/
141
142typedef struct exec_info_s
143{
144    xptr_t             parent_xp;      /*! extended pointer on parent process descriptor    */
145
146    xptr_t             stdin_xp;       /*! extended pointer on stdin  pseudo-file           */
147    char               path[CONFIG_VFS_MAX_PATH_LENGTH];   /*!  .elf file path              */
148
149    char            ** args_pointers;  /*! physical base address of array of pointers       */
150    char             * args_buf_base;  /*! physical base address of kernel args buffer      */
151    uint32_t           args_nr;        /*! actual number of arguments                       */
152
153    char            ** envs_pointers;  /*! physical base address of array of pointers       */
154    char             * envs_buf_base;  /*! physical base address of kernel args buffer      */
155    char             * envs_buf_free;  /*! physical address of first free slot in envs_buf  */
156    uint32_t           envs_nr;        /*! actual number of environment variables           */
157}
158exec_info_t;
159
160/***************   Process Descriptor Operations    *****************************************/
161
162/*********************************************************************************************
163 * This function allocates memory in local cluster for a process descriptor.
164 *********************************************************************************************
165 * @ returns pointer on process descriptor if success / return NULL if failure
166 ********************************************************************************************/
167process_t * process_alloc();
168
169/*********************************************************************************************
170 * This function releases memory in local cluster for a process descriptor.
171 *********************************************************************************************
172 * @ process      : pointer on process descriptor to release.
173 ********************************************************************************************/
174void process_free( process_t * process );
175
176/*********************************************************************************************
177 * This function allocates memory and initializes the "process_init" descriptor and the
178 * associated "thread_init" descriptor. It should be called once at the end of the kernel
179 * initialisation procedure, by the kernel "process_zero".
180 * The "process_init" is the first user process, and all other user processes will be forked
181 * from this process. The code executed by "process_init" is stored in a .elf file, whose
182 * pathname is defined by the CONFIG_PROCESS_INIT_PATH argument. It uses fork/exec syscalls
183 * to create the "shell" user process, and various other user daemon processes.
184 * Practically, it builds the exec_info structure, registers the stdin / stdout / stderr
185 * pseudo-file descriptors and the vfs_root and vfs_cwd in parent process_zero, and calls
186 * the generic process_make_exec() function, that makes the real job.
187 ********************************************************************************************/
188void process_init_create();
189
190/*********************************************************************************************
191 * This function initializes a new process descriptor, in the reference cluster.
192 * The PID value must have been defined previously by the owner cluster manager.
193 * The reference cluster can be different from the owner cluster.
194 * It set the pid / ppid / ref_xp fields.
195 * It registers this process descriptor in three lists:
196 * - the children_list in the parent reference process descriptor.
197 * - the local_list, rooted in the reference cluster manager.
198 * - the copies_list, rooted in the owner cluster manager.
199 * It resets the embedded structures such as the VMM or the file descriptor array.
200 *********************************************************************************************
201 * @ process      : [in] pointer on process descriptor to initialize.
202 * @ pid          : [in] process identifier defined by owner cluster.
203 * @ parent_xp    : [in] extended pointer on parent process.
204 ********************************************************************************************/
205void process_reference_init( process_t * process,
206                             pid_t       pid,
207                             xptr_t      parent_xp );
208
209/*********************************************************************************************
210 * This function initializes a copy process descriptor, in the local cluster,
211 * from information defined in the reference remote process descriptor.
212 *********************************************************************************************
213 * @ process              : [in] local pointer on process descriptor to initialize.
214 * @ reference_process_xp : [in] extended pointer on reference process descriptor.
215 * @ return 0 if success / return ENOMEM if failure
216 ********************************************************************************************/
217error_t process_copy_init( process_t * local_process,
218                           xptr_t      reference_process_xp );
219
220/*********************************************************************************************
221 * This function releases all memory allocated for a process descriptor in the local cluster,
222 * including memory allocated for embedded substructures (fd_array, vmm, etc).
223 * The local th_tbl[] array must be empty.
224 *********************************************************************************************
225 * @ process     : pointer on the process descriptor.
226 ********************************************************************************************/
227void process_destroy( process_t * process );
228
229/*********************************************************************************************
230 * This function kills a user process in a given cluster.
231 * It can be directly called in the reference cluster, or it can be called through the
232 * PROCESS_KILL RPC.
233 * - In a first loop, it set the THREAD_SIG_KILL signal to all threads of process.
234 * - In a second loop, it wait, for each thread the reset of the THREAD_SIG_KILL signal
235 *   by the scheduler, and completes the thread descriptor destruction.
236 *********************************************************************************************
237 * @ process     : pointer on the process descriptor.
238 ********************************************************************************************/
239void process_kill( process_t * process );
240
241/*********************************************************************************************
242 * This function returns a pointer on the local copy of a process identified by its PID.
243 * If this local copy does not exist yet, it is dynamically created, from the reference
244 * process descriptor, registered in the global copies_list, and registered in the local_list.
245 * This function is used by the thread_user_create() function.
246 *********************************************************************************************
247 * @ pid     : searched process identifier.
248 * @ returns pointer on the local process descriptor if success / returns NULL if failure.
249 ********************************************************************************************/
250process_t * process_get_local_copy( pid_t pid );
251
252/*********************************************************************************************
253 * This function allocates memory and initializes a new user process descriptor,
254 * and the associated main thread, from information found in the <exec_info> structure
255 * (defined in the process.h file), that must be built by the caller.
256 * The new process inherits from the parent process (i) the open file descriptors, (ii) the
257 * vfs_root and the vfs_cwd inodes.
258 * It accesses the .elf file to get the size of the code and data segments, and initializes
259 * the vsegs list in the VMM.
260 * It is executed in the local cluster, that becomes both "owner" and "reference".
261 * - It can be called by the process_init_create() function to build the "init" process.
262 * - It can be called directly by the sys_exec() function in case of local exec.
263 * - It can be called through the rpc_process_exec_server() function in case of remote exec.
264 *********************************************************************************************
265 * @ exec_info   : [in]  pointer on the exec_info structure.
266 * @ return 0 if success / return non-zero if error.
267 ********************************************************************************************/
268error_t process_make_exec( exec_info_t * exec_info );
269
270
271/********************   Signal Management Operations   **************************************/
272
273/*********************************************************************************************
274 * This function TODO [AG]
275 ********************************************************************************************/
276void process_signal_handler( process_t * process );
277
278
279/********************   File Management Operations   ****************************************/
280
281/*********************************************************************************************
282 * This function initializes all entries of the local fd_array as empty.
283 *********************************************************************************************
284 * @ process  : pointer on the local process descriptor.
285 ********************************************************************************************/
286void process_fd_init( process_t * process );
287
288/*********************************************************************************************
289 * This function uses as many remote accesses as required, to reset an entry in fd_array[],
290 * in all clusters containing a copy. The entry is identified by the <file_id> argument.
291 * This function must be executed by a thread running reference cluster, that contains
292 * the complete list of process descriptors copies.
293 *********************************************************************************************
294 * @ process  : pointer on the local process descriptor.
295 * @ file_id  : file descriptor index in the fd_array.
296 ********************************************************************************************/
297void process_fd_remove( process_t * process,
298                        uint32_t    file_id );
299
300/*********************************************************************************************
301 * This function returns an extended pointer on a file descriptor identified by its index
302 * in fd_array. It can be called by any thread running in any cluster.
303 * It accesses first the local process descriptor. In case of local miss, it uses remote
304 * access to access the reference process descriptor.
305 * It updates the local fd_array when the file descriptor exists in reference cluster.
306 * The file descriptor refcount is not incremented.
307 *********************************************************************************************
308 * @ process  : pointer on the local process descriptor.
309 * @ file_id  : file descriptor index in the fd_array.
310 * @ return extended pointer on file descriptor if success / return XPTR_NULL if not found.
311 ********************************************************************************************/
312xptr_t process_fd_get_xptr( process_t * process,
313                            uint32_t    file_id );
314
315/*********************************************************************************************
316 * This function checks the number of open files for a given process.
317 * It can be called by any thread in any cluster, because it uses portable remote access
318 * primitives to access the reference process descriptor.
319 *********************************************************************************************
320 * @ returns true if file descriptor array full.
321 ********************************************************************************************/
322bool_t process_fd_array_full();
323
324/*********************************************************************************************
325 * This function allocates a free slot in the fd_array of the reference process,
326 * register the <file_xp> argument in the allocated slot, and return the slot index.
327 * It can be called by any thread in any cluster, because it uses portable remote access
328 * primitives to access the reference process descriptor.
329 *********************************************************************************************
330 * @ file_xp  : extended pointer on the file descriptor to be registered.
331 * @ file_id  : [out] buffer for fd_array slot index.
332 * @ return 0 if success / return EMFILE if array full.
333 ********************************************************************************************/
334error_t process_fd_register( xptr_t      file_xp,
335                             uint32_t  * file_id );
336
337/*********************************************************************************************
338 * This function copies all non-zero entries from a remote <src_xp> fd_array,
339 * embedded in a process descriptor, to another remote <dst_xp> fd_array, embedded
340 * in another process descriptor. The calling thread can be running in any cluster.
341 * It takes the remote lock protecting the <src_xp> fd_array during the copy.
342 * For each involved file descriptor, the refcount is incremented.
343 *********************************************************************************************
344 * @ dst_xp   : extended pointer on the destination fd_array_t.
345 * @ src_xp   : extended pointer on the source fd_array_t.
346 ********************************************************************************************/
347void process_fd_remote_copy( xptr_t dst_xp,
348                             xptr_t src_xp );
349
350
351
352/********************   Thread Related Operations   *****************************************/
353
354/*********************************************************************************************
355 * This function registers a new thread in the local process descriptor.
356 * It checks that there is an available slot in the local th_tbl[] array,
357 * allocates a new LTID, and registers the new thread in the th_tbl[].
358 * WARNING : the lock protecting the th_tbl[] must be taken by the caller.
359 *********************************************************************************************
360 * @ process  : pointer on the local process descriptor.
361 * @ thread   : pointer on new thread to be registered.
362 * @ trdid    : [out] address of buffer for allocated trdid.
363 * @ returns 0 if success / returns non zero if no slot available.
364 ********************************************************************************************/
365error_t process_register_thread( process_t       * process,
366                                 struct thread_s * thread,
367                                 trdid_t         * trdid );
368
369/*********************************************************************************************
370 * This function removes a thread registration from the local process descriptor.
371 * WARNING : the lock protecting the th_tbl[] must be taken by the caller.
372 *********************************************************************************************
373 * @ thread   : local pointer on thread to be removed.
374 ********************************************************************************************/
375void process_remove_thread( struct thread_s * thread );
376
377
378
379#endif  /* _PROCESS_H_ */
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