source: trunk/kernel/kern/process.h @ 408

Last change on this file since 408 was 408, checked in by alain, 4 years ago

Fix several bugs in the fork() syscall.

File size: 25.1 KB
Line 
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 * in the parent process owner cluster.
141 ********************************************************************************************/
142
143typedef struct exec_info_s
144{
145    pid_t              pid;            /*! process identifier (both parent and child)       */
146
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 in the local cluster. It is called once at the end
179 * of the kernel initialisation procedure, by the local kernel process.
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.
183 * Practically, it builds the exec_info structure, and calls the process_make_exec()
184 * function, that make the real job.
185 ********************************************************************************************/
186void process_init_create();
187
188/*********************************************************************************************
189 * This function initialize, in each cluster, the kernel "process_zero", that is the owner
190 * of all kernel threads in a given cluster. It is called by the kernel_init() function.
191 * Both the PID and PPID fields are set to zero, and the ref_xp is the local process_zero.
192 * The th_tbl[] is initialized as empty.
193 *********************************************************************************************
194 * @ process      : [in] pointer on local process descriptor to initialize.
195 ********************************************************************************************/
196void process_zero_init( process_t * process );
197
198/*********************************************************************************************
199 * This function initializes a local, reference user process descriptor from another process
200 * descriptor, defined by the <model_xp> argument. The <process> descriptor, the <pid>, and
201 * the <ppid> arguments must be previously defined by the caller.
202 * It can be called by three functions, depending on the process type:
203 * 1) if "process" is the user "process_init", the parent is the kernel process. It is
204 *    called once, by the process_init_create() function in cluster[xmax-1][ymax-1].
205 * 2) if the caller is the process_make_fork() function, the model is generally a remote
206 *    process, that is also the parent process.
207 * 3) if the caller is the process_make_exec() function, the model is always a local process,
208 *    but the parent is the parent of the model process.
209 *
210 * The following fields are initialised (for all process but process_zero).
211 * - It set the pid / ppid / ref_xp fields.
212 * - It initializes an empty VMM (no vsegs registered in VSL and GPT).
213 * - It initializes the FDT, defining the three pseudo files STDIN / STDOUT / STDERR.
214 * - It set the root_xp, bin_xp, cwd_xp fields.
215 * - It reset the children list as empty, but does NOT register it in parent children list.
216 * - It reset the TH_TBL list of threads as empty.
217 * - It reset the semaphore / mutex / barrier / condvar lists as empty.
218 * - It registers the process in the local_list, rooted in the local cluster manager.
219 * - It registers the process in the copies_list, rooted in the owner cluster manager.
220 * - It registers the process extended pointer in the local pref_tbl[] array.
221 *********************************************************************************************
222 * @ process      : [in] pointer on local process descriptor to initialize.
223 * @ pid          : [in] process identifier.
224 * @ ppid         : [in] parent process identifier.
225 * @ model_xp     : [in] extended pointer on model process descriptor (local or remote).
226 ********************************************************************************************/
227void process_reference_init( process_t * process,
228                             pid_t       pid,
229                             pid_t       ppid,
230                             xptr_t      model_xp );
231
232/*********************************************************************************************
233 * This function initializes a copy process descriptor, in the local cluster,
234 * from information defined in the reference remote process descriptor.
235 *********************************************************************************************
236 * @ process              : [in] local pointer on process descriptor to initialize.
237 * @ reference_process_xp : [in] extended pointer on reference process descriptor.
238 * @ return 0 if success / return ENOMEM if failure
239 ********************************************************************************************/
240error_t process_copy_init( process_t * local_process,
241                           xptr_t      reference_process_xp );
242
243/*********************************************************************************************
244 * This function releases all memory allocated for a process descriptor in the local cluster,
245 * including memory allocated for embedded substructures (fd_array, vmm, etc).
246 * The local th_tbl[] array must be empty.
247 *********************************************************************************************
248 * @ process     : pointer on the process descriptor.
249 ********************************************************************************************/
250void process_destroy( process_t * process );
251
252/*********************************************************************************************
253 * This function kills a user process in a given cluster.
254 * It can be directly called in the reference cluster, or it can be called through the
255 * PROCESS_KILL RPC.
256 * - In a first loop, it set the THREAD_SIG_KILL signal to all threads of process.
257 * - In a second loop, it wait, for each thread the reset of the THREAD_SIG_KILL signal
258 *   by the scheduler, and completes the thread descriptor destruction.
259 *********************************************************************************************
260 * @ process     : pointer on the process descriptor.
261 ********************************************************************************************/
262void process_kill( process_t * process );
263
264/*********************************************************************************************
265 * This function returns a pointer on the local copy of a process identified by its PID.
266 * If this local copy does not exist yet, it is dynamically created, from the reference
267 * process descriptor, registered in the global copies_list, and registered in the local_list.
268 * This function is used by the thread_user_create() function.
269 *********************************************************************************************
270 * @ pid     : searched process identifier.
271 * @ returns pointer on the local process descriptor if success / returns NULL if failure.
272 ********************************************************************************************/
273process_t * process_get_local_copy( pid_t pid );
274
275/*********************************************************************************************
276 * This function implements the exec() system call, and is called by the sys_exec() function.
277 * It is also called by the process_init_create() function to build the "init" process.
278 * The "new" process keep the "old" process PID and PPID, all open files, and env variables,
279 * the vfs_root and vfs_cwd, but build a brand new memory image (new VMM from the new .elf).
280 * It actually creates a "new" reference process descriptor, saves all relevant information
281 * from the "old" reference process descriptor to the "new" process descriptor.
282 * It completes the "new" process descriptor, from information found in the <exec_info>
283 * structure (defined in the process.h file), that must be built by the caller.
284 * It creates and initializes the associated main thread. It finally destroys all copies
285 * of the "old" process in all clusters, and all the old associated threads.
286 * It is executed in the local cluster, that becomes both the "owner" and the "reference"
287 * cluster for the "new" process.
288 *********************************************************************************************
289 * @ exec_info   : [in]  pointer on the exec_info structure.
290 * @ return 0 if success / return non-zero if error.
291 ********************************************************************************************/
292error_t process_make_exec( exec_info_t * exec_info );
293
294/*********************************************************************************************
295 * This function implement the fork() system call, and is called by the sys_fork() function.
296 * It allocates memory and initializes a new "child" process descriptor, and the
297 * associated "child" thread descriptor in the local cluster. This function can involve
298 * up to three different clusters :
299 * - the local (child) cluster can be any cluster defined by the sys_fork function.
300 * - the parent cluster must be the reference clusterfor the parent process.
301 * - the client cluster containing the thread requestingthe fork can be any cluster.
302 * The new "child" process descriptor is initialised from informations found in the "parent"
303 * reference process descriptor, containing the complete process description.
304 * The new "child" thread descriptor is initialised from informations found in the "parent"
305 * thread descriptor.
306 *********************************************************************************************
307 * @ parent_process_xp  : extended pointer on the reference parent process.
308 * @ parent_thread_xp   : extended pointer on the parent thread requesting the fork.
309 * @ child_pid          : [out] child process identifier.
310 * @ child_thread_ptr   : [out] local pointer on child thread in target cluster.
311 * @ return 0 if success / return non-zero if error.
312 ********************************************************************************************/
313error_t process_make_fork(  xptr_t             parent_process_xp,
314                            xptr_t             parent_thread_xp,
315                            pid_t            * child_pid, 
316                            struct thread_s ** child_thread_ptr );
317
318/********************   File Management Operations   ****************************************/
319
320/*********************************************************************************************
321 * This function initializes all entries of the local fd_array as empty.
322 *********************************************************************************************
323 * @ process  : pointer on the local process descriptor.
324 ********************************************************************************************/
325void process_fd_init( process_t * process );
326
327/*********************************************************************************************
328 * This function uses as many remote accesses as required, to reset an entry in fd_array[],
329 * in all clusters containing a copy. The entry is identified by the <fdid> argument.
330 * This function must be executed by a thread running reference cluster, that contains
331 * the complete list of process descriptors copies.
332 *********************************************************************************************
333 * @ process  : pointer on the local process descriptor.
334 * @ fdid     : file descriptor index in the fd_array.
335 ********************************************************************************************/
336void process_fd_remove( process_t * process,
337                        uint32_t    fdid );
338
339/*********************************************************************************************
340 * This function returns an extended pointer on a file descriptor identified by its index
341 * in fd_array. It can be called by any thread running in any cluster.
342 * It accesses first the local process descriptor. In case of local miss, it uses remote
343 * access to access the reference process descriptor.
344 * It updates the local fd_array when the file descriptor exists in reference cluster.
345 * The file descriptor refcount is not incremented.
346 *********************************************************************************************
347 * @ process  : pointer on the local process descriptor.
348 * @ fdid     : file descriptor index in the fd_array.
349 * @ return extended pointer on file descriptor if success / return XPTR_NULL if not found.
350 ********************************************************************************************/
351xptr_t process_fd_get_xptr( process_t * process,
352                            uint32_t    fdid );
353
354/*********************************************************************************************
355 * This function checks the number of open files for a given process.
356 * It can be called by any thread in any cluster, because it uses portable remote access
357 * primitives to access the reference process descriptor.
358 *********************************************************************************************
359 * @ returns true if file descriptor array full.
360 ********************************************************************************************/
361bool_t process_fd_array_full();
362
363/*********************************************************************************************
364 * This function allocates a free slot in the fd_array of the reference process,
365 * register the <file_xp> argument in the allocated slot, and return the slot index.
366 * It can be called by any thread in any cluster, because it uses portable remote access
367 * primitives to access the reference process descriptor.
368 *********************************************************************************************
369 * @ file_xp  : extended pointer on the file descriptor to be registered.
370 * @ fdid     : [out] buffer for fd_array slot index.
371 * @ return 0 if success / return EMFILE if array full.
372 ********************************************************************************************/
373error_t process_fd_register( process_t * process,
374                             xptr_t      file_xp,
375                             uint32_t  * fdid );
376
377/*********************************************************************************************
378 * This function copies all non-zero entries from a remote <src_xp> fd_array,
379 * embedded in a process descriptor, to another remote <dst_xp> fd_array, embedded
380 * in another process descriptor. The calling thread can be running in any cluster.
381 * It takes the remote lock protecting the <src_xp> fd_array during the copy.
382 * For each involved file descriptor, the refcount is incremented.
383 *********************************************************************************************
384 * @ dst_xp   : extended pointer on the destination fd_array_t.
385 * @ src_xp   : extended pointer on the source fd_array_t.
386 ********************************************************************************************/
387void process_fd_remote_copy( xptr_t dst_xp,
388                             xptr_t src_xp );
389
390
391
392/********************   Thread Related Operations   *****************************************/
393
394/*********************************************************************************************
395 * This function registers a new thread in the local process descriptor.
396 * It checks that there is an available slot in the local th_tbl[] array,
397 * allocates a new LTID, and registers the new thread in the th_tbl[].
398 * WARNING : the lock protecting the th_tbl[] must be taken by the caller.
399 *********************************************************************************************
400 * @ process  : pointer on the local process descriptor.
401 * @ thread   : pointer on new thread to be registered.
402 * @ trdid    : [out] address of buffer for allocated trdid.
403 * @ returns 0 if success / returns non zero if no slot available.
404 ********************************************************************************************/
405error_t process_register_thread( process_t       * process,
406                                 struct thread_s * thread,
407                                 trdid_t         * trdid );
408
409/*********************************************************************************************
410 * This function removes a thread registration from the local process descriptor.
411 * WARNING : the lock protecting the th_tbl[] must be taken by the caller.
412 *********************************************************************************************
413 * @ thread   : local pointer on thread to be removed.
414 ********************************************************************************************/
415void process_remove_thread( struct thread_s * thread );
416
417
418
419#endif  /* _PROCESS_H_ */
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