Annotation of freem/src/shmmgr.c, revision 1.15
1.1 snw 1: /*
1.15 ! snw 2: * $Id: shmmgr.c,v 1.14 2025/05/08 14:47:26 snw Exp $
1.1 snw 3: * shared memory manager
4: *
5: *
1.3 snw 6: * Author: Serena Willis <snw@coherent-logic.com>
1.1 snw 7: * Copyright (C) 1998 MUG Deutschland
1.4 snw 8: * Copyright (C) 2020, 2025 Coherent Logic Development LLC
1.1 snw 9: *
10: *
11: * This file is part of FreeM.
12: *
13: * FreeM is free software: you can redistribute it and/or modify
14: * it under the terms of the GNU Affero Public License as published by
15: * the Free Software Foundation, either version 3 of the License, or
16: * (at your option) any later version.
17: *
18: * FreeM is distributed in the hope that it will be useful,
19: * but WITHOUT ANY WARRANTY; without even the implied warranty of
20: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21: * GNU Affero Public License for more details.
22: *
23: * You should have received a copy of the GNU Affero Public License
24: * along with FreeM. If not, see <https://www.gnu.org/licenses/>.
25: *
1.5 snw 26: * $Log: shmmgr.c,v $
1.15 ! snw 27: * Revision 1.14 2025/05/08 14:47:26 snw
! 28: * Break everything to begin shared memory rewrite
! 29: *
1.14 snw 30: * Revision 1.13 2025/04/16 17:36:12 snw
31: * Add FreeBSD shm cleanup script
32: *
1.13 snw 33: * Revision 1.12 2025/04/15 21:57:10 snw
34: * Fix SysV IPC bugs on FreeBSD
35: *
1.12 snw 36: * Revision 1.11 2025/04/15 21:08:51 snw
37: * Add some useful debug output
38: *
1.11 snw 39: * Revision 1.10 2025/04/15 19:26:13 snw
40: * Remove extra whitespace
41: *
1.10 snw 42: * Revision 1.9 2025/04/15 16:49:36 snw
43: * Make use of logprintf throughout codebase
44: *
1.9 snw 45: * Revision 1.8 2025/04/14 19:46:18 snw
46: * Add SHM_REMAP flag to shmat on FreeBSD
47: *
1.8 snw 48: * Revision 1.7 2025/04/09 19:52:02 snw
49: * Eliminate as many warnings as possible while building with -Wall
50: *
1.7 snw 51: * Revision 1.6 2025/04/04 19:43:18 snw
52: * Switch to using environment catalog to determine user and group for environment, and remove -u and -g flags from freem
53: *
1.6 snw 54: * Revision 1.5 2025/03/24 02:56:50 snw
55: * Shared memory compatibility fixes for OS/2
56: *
1.5 snw 57: * Revision 1.4 2025/03/09 19:50:47 snw
58: * Second phase of REUSE compliance and header reformat
59: *
1.4 snw 60: *
61: * SPDX-FileCopyrightText: (C) 2025 Coherent Logic Development LLC
62: * SPDX-License-Identifier: AGPL-3.0-or-later
1.1 snw 63: **/
64:
65: #include <stdlib.h>
66: #include <stdio.h>
67: #include <assert.h>
68: #include <string.h>
69: #include <unistd.h>
70: #include <errno.h>
71: #include <signal.h>
72:
73: #include "shmmgr.h"
74: #include "mpsdef.h"
75: #include "locktab.h"
1.9 snw 76: #include "log.h"
1.1 snw 77:
78: #include <sys/types.h>
79: #include <sys/ipc.h>
80: #include <sys/sem.h>
81:
1.5 snw 82: #if !defined(__OpenBSD__) && !defined(__APPLE__) && !defined(__OS2__)
1.1 snw 83: union semun {
84: int val; /* Value for SETVAL */
85: struct semid_ds *buf; /* Buffer for IPC_STAT, IPC_SET */
86: unsigned short *array; /* Array for GETALL, SETALL */
87: struct seminfo *__buf; /* Buffer for IPC_INFO
88: (Linux-specific) */
89: };
90: #endif
91:
92: int semid_shm;
93: extern int semid_locktab;
94: extern int semid_jobtab;
95: extern int semid_tp;
96: extern int semid_symtab;
97:
98: void shm_daemon_init(void);
99:
100: shm_config_t *shm_config = (shm_config_t *) NULL;
101:
1.12 snw 102: #if defined(__FreeBSD__)
1.13 snw 103: # define FM_SHM_PERMS 0777
1.12 snw 104: #else
105: # define FM_SHM_PERMS 0770
106: #endif
107:
1.1 snw 108: short shm_init(const size_t seg_size)
109: {
110: size_t alloc_map_size;
111: long pg_size;
112: key_t shm_sk;
1.13 snw 113:
114: #if defined(__FreeBSD__)
115: struct shmid_ds ctl;
116: #endif
117:
1.1 snw 118: shm_sk = ftok (config_file, 5);
119: pg_size = sysconf (_SC_PAGESIZE);
120:
121: shm_config = (shm_config_t *) malloc (sizeof (shm_config_t));
122: NULLPTRCHK(shm_config,"shm_init");
123:
124: /* figure out how many pages we can fit in the segment, accounting for header size */
125: shm_config->pgct = (seg_size / pg_size) - sizeof (shm_hdr_t);
126:
127: /* how big will the alloc map be? */
128: alloc_map_size = shm_config->pgct * sizeof (shm_page_t);
129:
130: shm_config->segsiz = seg_size + alloc_map_size + pg_size;
131: shm_config->key = ftok (config_file, 1);
132: shm_config->pgsiz = pg_size;
1.12 snw 133:
134: shm_config->seg_id = shmget (shm_config->key, shm_config->segsiz, FM_SHM_PERMS | IPC_CREAT);
1.1 snw 135: if (shm_config->seg_id == -1) {
136: if (errno == 22) {
1.9 snw 137: logprintf (FM_LOG_ERROR, "shm_init: cannot get shared memory segment of %ld bytes", (unsigned long) shm_config->segsiz);
138: fprintf (stderr, "\r\nYou may need to tune your kernel parameters, or manually set a smaller shared memory segment size in both the FreeM daemon and each interpreter process by using the `-S` command-line flag.\r\n\r\nPlease refer to the FreeM Platform Notes for your operating system for details.\r\n");
1.1 snw 139: }
140: return SHMS_GET_ERR;
141: }
142:
143: #if !defined(__arm__)
144: shm_config->dta = shmat (shm_config->seg_id, NULL, 0);
145: #else
146: shm_config->dta = shmat (shm_config->seg_id, (void *) 0x1000000, 0);
147: #endif
148:
149: if (shm_config->dta == (void *) -1) {
1.13 snw 150: logprintf (FM_LOG_FATAL, "shm_init: shmat() failed (error code %d [%s])", errno, strerror (errno));
1.1 snw 151: }
152: /* view the first sizeof (shm_hdr_t) bytes of the data area as an shm_hdr_t */
153: shm_config->hdr = (shm_hdr_t *) shm_config->dta;
154:
155: if (shm_config->hdr->magic != shm_config->key) {
156:
157: /* the shm segment is brand new */
158: first_process = TRUE;
159:
160: shm_daemon_init ();
161:
162: }
163: else {
164:
165: /* this shared mem segment was initialized before */
166: int daemon_chk;
167:
168: /* check if the daemon recorded in the header is actually running */
169: daemon_chk = kill (shm_config->hdr->first_process, 0);
170:
171: if (daemon_chk == -1 && errno == ESRCH) {
172:
1.9 snw 173: logprintf (FM_LOG_WARNING, "shm_init: recovering from crashed daemon pid %ld", shm_config->hdr->first_process);
1.1 snw 174:
175: first_process = TRUE;
176:
177: shm_daemon_init ();
178:
179: }
180: else {
181:
182:
183: first_process = FALSE;
184:
185: semid_shm = semget (shm_sk, 1, 0);
186: if (semid_shm == -1) {
1.9 snw 187: logprintf (FM_LOG_FATAL, "shm_init: could not attach to shared memory semaphore [%s]", strerror (errno));
1.1 snw 188: }
189:
1.8 snw 190:
1.15 ! snw 191: shm_config->buf = SBM(SHMALIGN(SOM(shm_config->dta) + (sizeof (shm_hdr_t) * shm_config->pgct)));
1.1 snw 192:
193:
194: }
195:
196: }
197:
198: locktab_init ();
199:
200: assert(shm_address_to_page_num(shm_page_num_to_address(20)) == 20);
201:
202:
203: return TRUE;
204: }
205:
206: void shm_daemon_init(void)
207: {
208: union semun arg;
209: key_t shm_sk;
210: register int i;
211:
212: shm_sk = ftok (config_file, 5);
213:
214: semid_shm = semget (shm_sk, 1, 0660 | IPC_CREAT);
215: if (semid_shm == -1) {
1.9 snw 216: logprintf (FM_LOG_FATAL, "shm_init: failed to create shared memory semaphore [%s]", strerror (errno));
1.1 snw 217: }
218:
219: arg.val = 1;
220: if (semctl (semid_shm, 0, SETVAL, arg) == -1) {
1.9 snw 221: logprintf (FM_LOG_FATAL, "shm_init: failed to initialize shared memory semaphore [%s]", strerror (errno));
1.1 snw 222: }
223:
224: /* zero out the segment */
225: memset (shm_config->dta, 0, shm_config->segsiz);
226:
227: /* we are the process that created the segment: initialize everything */
228: shm_config->hdr->magic = shm_config->key;
229: shm_config->hdr->first_process = pid;
230:
231: /* store the address we got into the shm_hdr (borrowed from RSM) */
232: shm_config->hdr->shmad = shm_config->dta;
233: shm_config->hdr->maintenance_mode = 0;
234:
235: /* alloc_map comes after the header */
236: /*
237: shm_config->alloc_map = (shm_page_t *) (shm_config->dta + sizeof (shm_hdr_t));
238: */
239: shm_config->buf = SHMALIGN(shm_config->dta + (sizeof (shm_hdr_t) * shm_config->pgct));
1.9 snw 240: logprintf (FM_LOG_INFO, "shm_daemon_init: allocator buffer aligned at %p (system page size %ld)", shm_config->buf, sysconf (_SC_PAGESIZE));
1.1 snw 241:
242: for (i = 0; i < shm_config->pgct; i++) {
243: shm_config->hdr->alloc_map[i].is_first = FALSE;
244: shm_config->hdr->alloc_map[i].is_last = FALSE;
245: shm_config->hdr->alloc_map[i].pg_state = PG_FREE;
246: }
247:
248: }
249:
250: short shm_exit(void)
251: {
252: int res;
253: union semun arg;
254:
255: res = shmdt (shm_config->dta);
256:
257: if (res == -1) {
1.9 snw 258: logprintf (FM_LOG_ERROR, "shm_exit: failure in shmdt() [%s]", strerror (errno));
1.1 snw 259: return FALSE;
260: }
261:
262: if (first_process) {
263:
264: res = shmctl (shm_config->seg_id, IPC_RMID, 0);
265:
266: if (res == -1) {
1.9 snw 267: logprintf (FM_LOG_ERROR, "shm_exit: failure in shmctl() [%s]", strerror (errno));
1.1 snw 268: return FALSE;
269: }
270:
271: semctl (semid_shm, 0, IPC_RMID, arg);
272: semctl (semid_locktab, 0, IPC_RMID, arg);
273: semctl (semid_jobtab, 0, IPC_RMID, arg);
274: semctl (semid_tp, 0, IPC_RMID, arg);
275: semctl (semid_symtab, 0, IPC_RMID, arg);
276:
277: }
278:
279: return TRUE;
280:
281: }
282:
283: short shm_get_sem(void)
284: {
285:
286: int tries;
287: struct sembuf s = {0, -1, 0};
288:
289: for (tries = 0; tries < 3; tries++) {
290:
291: if (semop (semid_shm, &s, 1) != -1) {
292: return TRUE;
293: }
294:
295: sleep (1);
296:
297: }
298:
299: return FALSE;
300:
301: }
302:
303: short shm_release_sem(void)
304: {
305: struct sembuf s = {0, 1, 0};
306:
307: if (semop (semid_shm, &s, 1) != -1) {
308: return TRUE;
309: }
310:
311: return FALSE;
312: }
313:
314: void shm_set_maintenance_mode (const short maintenance_mode)
315: {
316: if (shm_get_sem () == TRUE) {
317: shm_config->hdr->maintenance_mode = maintenance_mode;
318:
319: shm_release_sem ();
320: }
321: }
322:
323: shm_page_t *shm_get_alloc_map_entry(const int page_number)
324: {
325: return &(shm_config->hdr->alloc_map[page_number]);
326: }
327:
328: void *shm_page_num_to_address(const int page_num)
329: {
330: return (void *) shm_config->buf + (shm_config->pgsiz * page_num);
331: }
332:
333: int shm_address_to_page_num(const void *address)
334: {
335: unsigned long val = (unsigned long) address - (unsigned long) shm_config->buf;
336: unsigned long new_val = val / shm_config->pgsiz;
337:
338: return (int) new_val;
339: }
340:
341: void *shm_alloc_pages(const int page_count)
342: {
343:
344: register int i;
345: register int j;
346:
347: int candidate_page = 0;
348: int free_pages_gotten = 0;
349:
350: shm_page_t *pg;
351:
352: if (shm_get_sem () == FALSE) {
1.9 snw 353: logprintf (FM_LOG_FATAL, "shm_alloc_pages: could not get exclusive access to shared memory");
1.1 snw 354: }
355:
356:
357: for (i = 0; i < shm_config->pgct; i++) {
358:
359: pg = shm_get_alloc_map_entry (i);
360: NULLPTRCHK(pg,"shm_alloc_pages");
361:
362: free_pages_gotten = 0;
363:
364: if (pg->pg_state == PG_FREE) {
365:
366: candidate_page = i;
367:
368: for (j = i; ((j < (i + page_count)) && (j < shm_config->pgct)); j++) {
369: pg = shm_get_alloc_map_entry (j);
370:
371: if (pg->pg_state == PG_FREE) free_pages_gotten++;
372:
373: }
374:
375: if (free_pages_gotten == page_count) {
376:
377: for (j = candidate_page; j < (candidate_page + page_count); j++) {
378: pg = shm_get_alloc_map_entry (j);
379:
380: pg->pg_state = PG_ALLOC;
381: pg->pid = pid;
382:
383: if (j == candidate_page) {
384: pg->is_first = TRUE;
385: }
386:
387: if (j == candidate_page + (page_count - 1)) {
388: pg->is_last = TRUE;
389: }
390:
391: }
392:
393: shm_release_sem ();
394:
395: return (void *) shm_config->buf + (shm_config->pgsiz * candidate_page);
396:
397: }
398:
399: }
400:
401: }
402:
403: shm_release_sem ();
404:
405: return (void *) NULL;
406:
407: }
408:
409:
410: void *shm_alloc(const size_t bytes)
411: {
412: int pages_needed = bytes / shm_config->pgsiz;
413: float extra = bytes % shm_config->pgsiz;
414:
415: if (extra > 0) {
416: pages_needed++;
417: }
418:
419: return shm_alloc_pages (pages_needed);
420: }
421:
422: void shm_free_page(const int page_number)
423: {
424: register int i;
425: shm_page_t *a = shm_get_alloc_map_entry (page_number);
426:
427: if (a->is_first == FALSE) {
1.9 snw 428: logprintf (FM_LOG_ERROR, "shm_free_page: attempt to free page in the middle of allocation chain");
1.1 snw 429: return;
430: }
431:
432: if (a->pg_state == PG_FREE) {
1.9 snw 433: logprintf (FM_LOG_FATAL, "shm_free_page: double free attempted in page %d", page_number);
1.1 snw 434: }
435:
436: if (shm_get_sem () == FALSE) {
1.9 snw 437: logprintf (FM_LOG_FATAL, "shm_free_page: could not get exclusive access to shared memory");
1.1 snw 438: }
439:
440:
441: for (i = page_number; i < shm_config->pgct; i++) {
442:
443: a = shm_get_alloc_map_entry (i);
444:
445: if (a->is_last) {
446: a->is_first = FALSE;
447: a->pg_state = PG_FREE;
448: a->pid = 0;
449: a->is_last = FALSE;
450:
451: shm_release_sem ();
452:
453: return;
454: }
455: else {
456: a->is_first = FALSE;
457: a->pg_state = PG_FREE;
458: a->pid = 0;
459: a->is_last = FALSE;
460: }
461:
462: }
463:
464: shm_release_sem ();
465:
466: }
467:
468: void shm_free(const void *addr)
469: {
470: shm_free_page (shm_address_to_page_num (addr));
471: }
472:
473: void shm_dump(void)
474: {
475:
476: printf ("SHARED MEMORY CONFIGURATION\r\n");
1.2 snw 477: printf (" pgsiz %ld\r\n", (unsigned long) shm_config->pgsiz);
1.1 snw 478: printf (" pgct %d\r\n", shm_config->pgct);
1.7 snw 479: printf (" key %d\r\n", shm_config->key);
1.1 snw 480: printf (" segid %d\r\n", shm_config->seg_id);
1.2 snw 481: printf (" sizeof shm_page_t %ld\r\n", (long) sizeof (shm_page_t));
482: printf (" segsiz %ld\r\n", (long) shm_config->segsiz);
1.1 snw 483: printf (" shm address %p\r\n", shm_config->dta);
1.2 snw 484: printf (" alloc_map size %ld\r\n", (unsigned long) sizeof (shm_page_t) * shm_config->pgct);
1.1 snw 485: printf (" buf address %p\r\n", shm_config->buf);
486: }
487:
488: void shm_dump_pages(void)
489: {
490:
491: register int i;
492: shm_page_t *p;
493:
494: printf ("%-10s%-10s%-10s%-10s%-10s\r\n", "PAGE", "PID", "BMHEAD", "BMTAIL", "STATE");
495:
496: for (i = 0; i < shm_config->pgct; i++) {
497:
498: p = shm_get_alloc_map_entry (i);
499:
500: printf ("%-10d%-10d%-10s%-10s%-10s\r\n",
501: i,
502: p->pid,
503: (p->is_first == TRUE) ? "Y" : "N",
504: (p->is_last == TRUE) ? "Y" : "N",
505: (p->pg_state == PG_FREE) ? "PG_FREE" : "PG_ALLOC");
506:
507: }
508:
509: }
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