Annotation of freem/src/shmmgr.c, revision 1.17
1.1 snw 1: /*
1.17 ! snw 2: * $Id: shmmgr.c,v 1.16 2025/05/12 14:26:15 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 $
1.17 ! snw 27: * Revision 1.16 2025/05/12 14:26:15 snw
! 28: * Revert bad change in shared memory manager
! 29: *
1.16 snw 30: * Revision 1.15 2025/05/09 19:44:50 snw
31: * Begin shm rework
32: *
1.15 snw 33: * Revision 1.14 2025/05/08 14:47:26 snw
34: * Break everything to begin shared memory rewrite
35: *
1.14 snw 36: * Revision 1.13 2025/04/16 17:36:12 snw
37: * Add FreeBSD shm cleanup script
38: *
1.13 snw 39: * Revision 1.12 2025/04/15 21:57:10 snw
40: * Fix SysV IPC bugs on FreeBSD
41: *
1.12 snw 42: * Revision 1.11 2025/04/15 21:08:51 snw
43: * Add some useful debug output
44: *
1.11 snw 45: * Revision 1.10 2025/04/15 19:26:13 snw
46: * Remove extra whitespace
47: *
1.10 snw 48: * Revision 1.9 2025/04/15 16:49:36 snw
49: * Make use of logprintf throughout codebase
50: *
1.9 snw 51: * Revision 1.8 2025/04/14 19:46:18 snw
52: * Add SHM_REMAP flag to shmat on FreeBSD
53: *
1.8 snw 54: * Revision 1.7 2025/04/09 19:52:02 snw
55: * Eliminate as many warnings as possible while building with -Wall
56: *
1.7 snw 57: * Revision 1.6 2025/04/04 19:43:18 snw
58: * Switch to using environment catalog to determine user and group for environment, and remove -u and -g flags from freem
59: *
1.6 snw 60: * Revision 1.5 2025/03/24 02:56:50 snw
61: * Shared memory compatibility fixes for OS/2
62: *
1.5 snw 63: * Revision 1.4 2025/03/09 19:50:47 snw
64: * Second phase of REUSE compliance and header reformat
65: *
1.4 snw 66: *
67: * SPDX-FileCopyrightText: (C) 2025 Coherent Logic Development LLC
68: * SPDX-License-Identifier: AGPL-3.0-or-later
1.1 snw 69: **/
70:
71: #include <stdlib.h>
72: #include <stdio.h>
73: #include <assert.h>
74: #include <string.h>
75: #include <unistd.h>
76: #include <errno.h>
77: #include <signal.h>
78:
79: #include "shmmgr.h"
80: #include "mpsdef.h"
81: #include "locktab.h"
1.9 snw 82: #include "log.h"
1.1 snw 83:
84: #include <sys/types.h>
85: #include <sys/ipc.h>
86: #include <sys/sem.h>
87:
1.5 snw 88: #if !defined(__OpenBSD__) && !defined(__APPLE__) && !defined(__OS2__)
1.1 snw 89: union semun {
90: int val; /* Value for SETVAL */
91: struct semid_ds *buf; /* Buffer for IPC_STAT, IPC_SET */
92: unsigned short *array; /* Array for GETALL, SETALL */
93: struct seminfo *__buf; /* Buffer for IPC_INFO
94: (Linux-specific) */
95: };
96: #endif
97:
98: int semid_shm;
99: extern int semid_locktab;
100: extern int semid_jobtab;
101: extern int semid_tp;
102: extern int semid_symtab;
103:
104: void shm_daemon_init(void);
105:
106: shm_config_t *shm_config = (shm_config_t *) NULL;
107:
1.12 snw 108: #if defined(__FreeBSD__)
1.13 snw 109: # define FM_SHM_PERMS 0777
1.12 snw 110: #else
111: # define FM_SHM_PERMS 0770
112: #endif
113:
1.1 snw 114: short shm_init(const size_t seg_size)
115: {
116: size_t alloc_map_size;
117: long pg_size;
118: key_t shm_sk;
1.13 snw 119:
120: #if defined(__FreeBSD__)
121: struct shmid_ds ctl;
122: #endif
123:
1.1 snw 124: shm_sk = ftok (config_file, 5);
125: pg_size = sysconf (_SC_PAGESIZE);
126:
127: shm_config = (shm_config_t *) malloc (sizeof (shm_config_t));
128: NULLPTRCHK(shm_config,"shm_init");
129:
130: /* figure out how many pages we can fit in the segment, accounting for header size */
1.17 ! snw 131: shm_config->pgct = (seg_size - sizeof (shm_hdr_t)) / pg_size;
1.1 snw 132:
133: /* how big will the alloc map be? */
134: alloc_map_size = shm_config->pgct * sizeof (shm_page_t);
135:
136: shm_config->segsiz = seg_size + alloc_map_size + pg_size;
137: shm_config->key = ftok (config_file, 1);
138: shm_config->pgsiz = pg_size;
1.12 snw 139:
140: shm_config->seg_id = shmget (shm_config->key, shm_config->segsiz, FM_SHM_PERMS | IPC_CREAT);
1.1 snw 141: if (shm_config->seg_id == -1) {
142: if (errno == 22) {
1.9 snw 143: logprintf (FM_LOG_ERROR, "shm_init: cannot get shared memory segment of %ld bytes", (unsigned long) shm_config->segsiz);
144: 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 145: }
146: return SHMS_GET_ERR;
147: }
148:
149: #if !defined(__arm__)
150: shm_config->dta = shmat (shm_config->seg_id, NULL, 0);
151: #else
152: shm_config->dta = shmat (shm_config->seg_id, (void *) 0x1000000, 0);
153: #endif
154:
155: if (shm_config->dta == (void *) -1) {
1.13 snw 156: logprintf (FM_LOG_FATAL, "shm_init: shmat() failed (error code %d [%s])", errno, strerror (errno));
1.1 snw 157: }
158: /* view the first sizeof (shm_hdr_t) bytes of the data area as an shm_hdr_t */
159: shm_config->hdr = (shm_hdr_t *) shm_config->dta;
160:
161: if (shm_config->hdr->magic != shm_config->key) {
162:
163: /* the shm segment is brand new */
164: first_process = TRUE;
165:
166: shm_daemon_init ();
167:
168: }
169: else {
170:
171: /* this shared mem segment was initialized before */
172: int daemon_chk;
173:
174: /* check if the daemon recorded in the header is actually running */
175: daemon_chk = kill (shm_config->hdr->first_process, 0);
176:
177: if (daemon_chk == -1 && errno == ESRCH) {
1.9 snw 178: logprintf (FM_LOG_WARNING, "shm_init: recovering from crashed daemon pid %ld", shm_config->hdr->first_process);
1.1 snw 179: first_process = TRUE;
180: shm_daemon_init ();
181: }
182: else {
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:
1.16 snw 190: shm_config->buf = SHMALIGN(shm_config->dta + (sizeof (shm_hdr_t) * shm_config->pgct));
1.1 snw 191: }
192:
193: }
194:
195: locktab_init ();
196:
197: assert(shm_address_to_page_num(shm_page_num_to_address(20)) == 20);
198:
199:
200: return TRUE;
201: }
202:
203: void shm_daemon_init(void)
204: {
205: union semun arg;
206: key_t shm_sk;
207: register int i;
208:
209: shm_sk = ftok (config_file, 5);
210:
211: semid_shm = semget (shm_sk, 1, 0660 | IPC_CREAT);
212: if (semid_shm == -1) {
1.9 snw 213: logprintf (FM_LOG_FATAL, "shm_init: failed to create shared memory semaphore [%s]", strerror (errno));
1.1 snw 214: }
215:
216: arg.val = 1;
217: if (semctl (semid_shm, 0, SETVAL, arg) == -1) {
1.9 snw 218: logprintf (FM_LOG_FATAL, "shm_init: failed to initialize shared memory semaphore [%s]", strerror (errno));
1.1 snw 219: }
220:
221: /* zero out the segment */
222: memset (shm_config->dta, 0, shm_config->segsiz);
223:
224: /* we are the process that created the segment: initialize everything */
225: shm_config->hdr->magic = shm_config->key;
226: shm_config->hdr->first_process = pid;
227:
228: /* store the address we got into the shm_hdr (borrowed from RSM) */
229: shm_config->hdr->shmad = shm_config->dta;
230: shm_config->hdr->maintenance_mode = 0;
231:
232: /* alloc_map comes after the header */
233: /*
234: shm_config->alloc_map = (shm_page_t *) (shm_config->dta + sizeof (shm_hdr_t));
235: */
236: shm_config->buf = SHMALIGN(shm_config->dta + (sizeof (shm_hdr_t) * shm_config->pgct));
1.9 snw 237: 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 238:
239: for (i = 0; i < shm_config->pgct; i++) {
240: shm_config->hdr->alloc_map[i].is_first = FALSE;
241: shm_config->hdr->alloc_map[i].is_last = FALSE;
242: shm_config->hdr->alloc_map[i].pg_state = PG_FREE;
243: }
244:
245: }
246:
247: short shm_exit(void)
248: {
249: int res;
250: union semun arg;
251:
252: res = shmdt (shm_config->dta);
253:
254: if (res == -1) {
1.9 snw 255: logprintf (FM_LOG_ERROR, "shm_exit: failure in shmdt() [%s]", strerror (errno));
1.1 snw 256: return FALSE;
257: }
258:
259: if (first_process) {
260:
261: res = shmctl (shm_config->seg_id, IPC_RMID, 0);
262:
263: if (res == -1) {
1.9 snw 264: logprintf (FM_LOG_ERROR, "shm_exit: failure in shmctl() [%s]", strerror (errno));
1.1 snw 265: return FALSE;
266: }
267:
268: semctl (semid_shm, 0, IPC_RMID, arg);
269: semctl (semid_locktab, 0, IPC_RMID, arg);
270: semctl (semid_jobtab, 0, IPC_RMID, arg);
271: semctl (semid_tp, 0, IPC_RMID, arg);
272: semctl (semid_symtab, 0, IPC_RMID, arg);
273:
274: }
275:
276: return TRUE;
277:
278: }
279:
280: short shm_get_sem(void)
281: {
282:
283: int tries;
284: struct sembuf s = {0, -1, 0};
285:
286: for (tries = 0; tries < 3; tries++) {
287:
288: if (semop (semid_shm, &s, 1) != -1) {
289: return TRUE;
290: }
291:
292: sleep (1);
293:
294: }
295:
296: return FALSE;
297:
298: }
299:
300: short shm_release_sem(void)
301: {
302: struct sembuf s = {0, 1, 0};
303:
304: if (semop (semid_shm, &s, 1) != -1) {
305: return TRUE;
306: }
307:
308: return FALSE;
309: }
310:
311: void shm_set_maintenance_mode (const short maintenance_mode)
312: {
313: if (shm_get_sem () == TRUE) {
314: shm_config->hdr->maintenance_mode = maintenance_mode;
315:
316: shm_release_sem ();
317: }
318: }
319:
320: shm_page_t *shm_get_alloc_map_entry(const int page_number)
321: {
322: return &(shm_config->hdr->alloc_map[page_number]);
323: }
324:
325: void *shm_page_num_to_address(const int page_num)
326: {
327: return (void *) shm_config->buf + (shm_config->pgsiz * page_num);
328: }
329:
330: int shm_address_to_page_num(const void *address)
331: {
332: unsigned long val = (unsigned long) address - (unsigned long) shm_config->buf;
333: unsigned long new_val = val / shm_config->pgsiz;
334:
335: return (int) new_val;
336: }
337:
338: void *shm_alloc_pages(const int page_count)
339: {
340:
341: register int i;
342: register int j;
343:
344: int candidate_page = 0;
345: int free_pages_gotten = 0;
346:
347: shm_page_t *pg;
348:
349: if (shm_get_sem () == FALSE) {
1.9 snw 350: logprintf (FM_LOG_FATAL, "shm_alloc_pages: could not get exclusive access to shared memory");
1.1 snw 351: }
352:
353:
354: for (i = 0; i < shm_config->pgct; i++) {
355:
356: pg = shm_get_alloc_map_entry (i);
357: NULLPTRCHK(pg,"shm_alloc_pages");
358:
359: free_pages_gotten = 0;
360:
361: if (pg->pg_state == PG_FREE) {
362:
363: candidate_page = i;
364:
365: for (j = i; ((j < (i + page_count)) && (j < shm_config->pgct)); j++) {
366: pg = shm_get_alloc_map_entry (j);
367:
368: if (pg->pg_state == PG_FREE) free_pages_gotten++;
369:
370: }
371:
372: if (free_pages_gotten == page_count) {
373:
374: for (j = candidate_page; j < (candidate_page + page_count); j++) {
375: pg = shm_get_alloc_map_entry (j);
376:
377: pg->pg_state = PG_ALLOC;
378: pg->pid = pid;
379:
380: if (j == candidate_page) {
381: pg->is_first = TRUE;
382: }
383:
384: if (j == candidate_page + (page_count - 1)) {
385: pg->is_last = TRUE;
386: }
387:
388: }
389:
390: shm_release_sem ();
391:
392: return (void *) shm_config->buf + (shm_config->pgsiz * candidate_page);
393:
394: }
395:
396: }
397:
398: }
399:
400: shm_release_sem ();
401:
402: return (void *) NULL;
403:
404: }
405:
406:
407: void *shm_alloc(const size_t bytes)
408: {
409: int pages_needed = bytes / shm_config->pgsiz;
410: float extra = bytes % shm_config->pgsiz;
411:
412: if (extra > 0) {
413: pages_needed++;
414: }
415:
416: return shm_alloc_pages (pages_needed);
417: }
418:
419: void shm_free_page(const int page_number)
420: {
421: register int i;
422: shm_page_t *a = shm_get_alloc_map_entry (page_number);
423:
424: if (a->is_first == FALSE) {
1.9 snw 425: logprintf (FM_LOG_ERROR, "shm_free_page: attempt to free page in the middle of allocation chain");
1.1 snw 426: return;
427: }
428:
429: if (a->pg_state == PG_FREE) {
1.9 snw 430: logprintf (FM_LOG_FATAL, "shm_free_page: double free attempted in page %d", page_number);
1.1 snw 431: }
432:
433: if (shm_get_sem () == FALSE) {
1.9 snw 434: logprintf (FM_LOG_FATAL, "shm_free_page: could not get exclusive access to shared memory");
1.1 snw 435: }
436:
437:
438: for (i = page_number; i < shm_config->pgct; i++) {
439:
440: a = shm_get_alloc_map_entry (i);
441:
442: if (a->is_last) {
443: a->is_first = FALSE;
444: a->pg_state = PG_FREE;
445: a->pid = 0;
446: a->is_last = FALSE;
447:
448: shm_release_sem ();
449:
450: return;
451: }
452: else {
453: a->is_first = FALSE;
454: a->pg_state = PG_FREE;
455: a->pid = 0;
456: a->is_last = FALSE;
457: }
458:
459: }
460:
461: shm_release_sem ();
462:
463: }
464:
465: void shm_free(const void *addr)
466: {
467: shm_free_page (shm_address_to_page_num (addr));
468: }
469:
470: void shm_dump(void)
471: {
472:
473: printf ("SHARED MEMORY CONFIGURATION\r\n");
1.2 snw 474: printf (" pgsiz %ld\r\n", (unsigned long) shm_config->pgsiz);
1.1 snw 475: printf (" pgct %d\r\n", shm_config->pgct);
1.7 snw 476: printf (" key %d\r\n", shm_config->key);
1.1 snw 477: printf (" segid %d\r\n", shm_config->seg_id);
1.2 snw 478: printf (" sizeof shm_page_t %ld\r\n", (long) sizeof (shm_page_t));
479: printf (" segsiz %ld\r\n", (long) shm_config->segsiz);
1.1 snw 480: printf (" shm address %p\r\n", shm_config->dta);
1.2 snw 481: printf (" alloc_map size %ld\r\n", (unsigned long) sizeof (shm_page_t) * shm_config->pgct);
1.1 snw 482: printf (" buf address %p\r\n", shm_config->buf);
483: }
484:
485: void shm_dump_pages(void)
486: {
487:
488: register int i;
489: shm_page_t *p;
490:
491: printf ("%-10s%-10s%-10s%-10s%-10s\r\n", "PAGE", "PID", "BMHEAD", "BMTAIL", "STATE");
492:
493: for (i = 0; i < shm_config->pgct; i++) {
494:
495: p = shm_get_alloc_map_entry (i);
496:
497: printf ("%-10d%-10d%-10s%-10s%-10s\r\n",
498: i,
499: p->pid,
500: (p->is_first == TRUE) ? "Y" : "N",
501: (p->is_last == TRUE) ? "Y" : "N",
502: (p->pg_state == PG_FREE) ? "PG_FREE" : "PG_ALLOC");
503:
504: }
505:
506: }
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