2 * lwp.c -- lightweight process creation, destruction and manipulation.
3 * Copyright (C) 1991-3 Stephen Crane.
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the Free
17 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 * author: Stephen Crane, (jsc@doc.ic.ac.uk), Department of Computing,
20 * Imperial College of Science, Technology and Medicine, 180 Queen's
21 * Gate, London SW7 2BZ, England.
30 #include "prototypes.h"
32 #if defined(_EMPTH_LWP)
35 #include <bounds/fix-args.h>
36 #include <bounds/unchecked.h>
39 struct lwpQueue LwpSchedQ[LWP_MAX_PRIO], LwpDeadQ;
41 struct lwpProc *LwpCurrent = NULL;
43 int LwpMaxpri = 0; /* maximum priority so far */
45 static sigset_t oldmask;
47 static void lwpStackCheckInit(struct lwpProc *newp);
48 static void lwpStackCheck(struct lwpProc *newp);
49 static void lwpStackCheckUsed(struct lwpProc *newp);
51 /* check stack direction */
70 * lwpReschedule -- schedule another process. we also check for dead
71 * processes here and free them.
76 static int lcount = LCOUNT;
77 static struct lwpProc *nextp;
79 static sigset_t tmask;
81 if (LwpCurrent && (LwpCurrent->flags & LWP_STACKCHECK)) {
82 lwpStackCheck(LwpCurrent);
85 int p = lwpSetPriority(LWP_MAX_PRIO - 1);
87 sigprocmask(SIG_SETMASK, &oldmask, &tmask);
88 sigprocmask(SIG_SETMASK, &tmask, &oldmask);
92 /* destroy dead threads */
93 lwpStatus(LwpCurrent, "Cleaning dead queue");
94 while (NULL != (nextp = lwpGetFirst(&LwpDeadQ))) {
95 if (nextp == LwpCurrent) {
96 lwpStatus(nextp, "OOOPS, we are running already dead thread");
100 lwpStatus(LwpCurrent, "Destroying done");
103 for (i = LwpMaxpri + 1; i--;) {
104 while (NULL != (nextp = lwpGetFirst(&LwpSchedQ[i]))) {
107 /* clean up after dead bodies */
108 lwpStatus(nextp, "got a dead body");
109 if (nextp == LwpCurrent) {
110 lwpStatus(nextp, "we are in it -- will bury later");
111 lwpAddTail(&LwpDeadQ, nextp);
114 /* fprintf(stderr, "Destroying done\n"); */
121 if (LwpCurrent == 0 && nextp == 0) {
122 fprintf(stderr, "No processes to run!\n");
126 lwpStatus(LwpCurrent, "switch out");
127 /* do context switch */
136 endpoint = &endpoint;
137 if (initcontext == NULL || endpoint < startpoint) {
138 i = lwpSave(LwpCurrent->context);
140 LwpCurrent->size = endpoint - startpoint;
141 LwpCurrent->sbtm = realloc(LwpCurrent->sbtm, LwpCurrent->size);
142 memcpy(LwpCurrent->sbtm, startpoint, LwpCurrent->size);
143 if (i = lwpSave(LwpCurrent->context)) {
144 memcpy(startpoint, LwpCurrent->sbtm, LwpCurrent->size);
150 i = lwpSave(LwpCurrent->context);
156 if (LwpCurrent != nextp && !(LwpCurrent && i)) {
157 /* restore previous context */
158 lwpStatus(nextp, "switch in %d", nextp->pri);
160 *LwpContextPtr = LwpCurrent->ud;
164 lwpRestore(LwpCurrent->context);
173 * lwpEntryPoint -- process entry point.
184 sigaddset(&set, SIGALRM);
185 sigprocmask(SIG_SETMASK, &set, &oldmask);
186 *LwpContextPtr = LwpCurrent->ud;
188 lwpStatus(LwpCurrent, "starting at entry point");
189 (*LwpCurrent->entry)(LwpCurrent->ud);
199 * lwpCreate -- create a process.
202 lwpCreate(int priority, void (*entry)(void *), int size, int flags, char *name, char *desc, int argc, char **argv, void *ud)
204 struct lwpProc *newp;
210 #endif /* UCONTEXT */
211 unsigned long stackp;
213 if (!(newp = malloc(sizeof(struct lwpProc))))
215 if (flags & LWP_STACKCHECK) {
216 /* Add a 1K buffer on each side of the stack */
217 size += 2 * LWP_REDZONE;
219 size += LWP_EXTRASTACK;
220 size += sizeof(stkalign_t);
221 if (!(s = malloc(size)))
224 newp->name = strdup(name);
225 newp->desc = strdup(desc);
230 if ((newp->flags & LWP_STACKCHECK) == 0) {
231 stackp = growsdown((void *)&x)
232 ? (unsigned long)s + size - sizeof(stkalign_t) - LWP_EXTRASTACK
233 : (unsigned long)s + LWP_EXTRASTACK;
235 sp.ss_sp = (void *)(stackp & -sizeof(stkalign_t));
239 sp = (void *)(stackp & -sizeof(stkalign_t));
240 #endif /* UCONTEXT */
243 /* round address off to stkalign_t */
244 stackp = ((long)s) + size - LWP_REDZONE -
245 LWP_EXTRASTACK - sizeof(stkalign_t);
247 sp.ss_sp = (void *)(stackp & -sizeof(stkalign_t));
250 newp->lowmark = (void *)(((long)sp.ss_sp) + LWP_EXTRASTACK);
252 sp = (void *)(stackp & -sizeof(stkalign_t));
253 newp->lowmark = (void *)(((long)sp) + LWP_EXTRASTACK);
254 #endif /* UCONTEXT */
257 stackp = ((long)s) + LWP_REDZONE + LWP_EXTRASTACK;
259 sp.ss_sp = (void *)(((long)stackp) & -sizeof(stkalign_t));
263 sp = (void *)(((long)stackp) & -sizeof(stkalign_t));
264 #endif /* UCONTEXT */
265 newp->lowmark = (void *)s;
266 newp->himark = (void *)(((long)s) + size - LWP_REDZONE);
269 if (LWP_MAX_PRIO <= priority)
270 priority = LWP_MAX_PRIO - 1;
271 if (LwpMaxpri < (newp->pri = priority))
272 LwpMaxpri = priority;
273 newp->sbtm = (void *)s;
276 if (flags & LWP_STACKCHECK)
277 lwpStackCheckInit(newp);
278 lwpStatus(newp, "creating process structure sbtm: %p",
281 lwpReady(LwpCurrent);
283 lwpInitContext(newp, &sp); /* architecture-dependent: from arch.c */
285 lwpInitContext(newp, sp); /* architecture-dependent: from arch.c */
286 #endif /* UCONTEXT */
292 lwpDestroy(struct lwpProc *proc)
294 if (proc->flags & LWP_STACKCHECK) {
295 lwpStackCheckUsed(proc);
298 lwpStatus(proc, "destroying sbtm: %p", proc->sbtm);
314 * lwpReady -- put process on ready queue. if null, assume current.
317 lwpReady(struct lwpProc *p)
321 lwpStatus(p, "added to run queue");
322 lwpAddTail(&LwpSchedQ[p->pri], p);
329 lwpGetUD(struct lwpProc *p)
340 lwpSetUD(struct lwpProc *p, char *ud)
351 lwpSetDesc(struct lwpProc *p, char *name, char *desc)
357 p->name = strdup(name);
358 p->desc = strdup(desc);
362 * lwpYield -- yield the processor to another thread.
367 lwpStatus(LwpCurrent, "yielding control");
368 lwpReady(LwpCurrent);
373 * cause the current process to be scheduled for deletion.
378 lwpStatus(LwpCurrent, "marking self as dead");
379 LwpCurrent->dead = 1;
384 * mark another process as dead, so it will never be rescheduled.
385 * remove any lingering FD action
388 lwpTerminate(struct lwpProc *p)
390 lwpStatus(p, "terminating process");
397 * set the thread's priority, returning the old.
398 * if the new priority is lower than the old, we reschedule.
401 lwpSetPriority(int new)
403 int old = LwpCurrent->pri;
405 if (LWP_MAX_PRIO <= new)
406 new = LWP_MAX_PRIO - 1;
409 LwpCurrent->pri = new;
410 lwpStatus(LwpCurrent, "resetting priority (%d -> %d)", old, new);
417 * initialise the coroutine structures
420 lwpInitSystem(int pri, char **ctxptr, int flags)
426 LwpContextPtr = ctxptr;
429 /* *LwpContextPtr = 0; */
430 if (!(LwpCurrent = calloc(1, sizeof(struct lwpProc))))
432 if (!(stack = malloc(64)))
434 if (LWP_MAX_PRIO <= pri)
435 pri = LWP_MAX_PRIO - 1;
438 LwpCurrent->next = 0;
439 LwpCurrent->sbtm = stack; /* dummy stack for "main" */
440 LwpCurrent->pri = pri;
441 LwpCurrent->dead = 0;
442 LwpCurrent->flags = flags & ~LWP_STACKCHECK;
443 LwpCurrent->name = "Main";
444 for (i = LWP_MAX_PRIO, q = LwpSchedQ; i--; q++)
445 q->head = q->tail = 0;
446 LwpDeadQ.head = LwpDeadQ.tail = 0;
447 /* must be lower in priority than us for this to work right */
448 sel = lwpCreate(0, lwpSelect, 16384, flags, "EventHandler",
449 "Select (main loop) Event Handler", 0, 0, 0);
456 * Initialize the entire stack (including both redzones) with the stack
457 * check mark. Thus, we can get some indication of how much stack was
461 lwpStackCheckInit(struct lwpProc *newp)
466 int lim = newp->size / sizeof(long);
467 if (!newp || !newp->sbtm)
469 for (lp = newp->sbtm, i = 0; i < lim; i++, lp++) {
476 * Check if the thread has overflowed/underflowed its stack.
477 * Should that happen, abort the process, as we cannot recover.
480 lwpStackCheck(struct lwpProc *newp)
482 register int end, amt;
483 register unsigned int i;
485 register int growsDown;
488 if (CANT_HAPPEN(!newp || !newp->himark || !newp->lowmark))
490 growsDown = growsdown(&marker);
491 for (lp = newp->himark, i = 0; i < LWP_REDZONE / sizeof(long);
493 if (*lp == LWP_CHECKMARK)
495 /* Stack overflow. */
498 while (i < LWP_REDZONE / sizeof(long)) {
499 if (*lp++ != LWP_CHECKMARK)
503 amt = (end + 1) * sizeof(long);
505 amt = (i + 1) * sizeof(long);
507 logerror("Thread %s stack overflow %d bytes (of %u)",
509 newp->size - 2 * LWP_REDZONE - (int)sizeof(stkalign_t));
512 for (lp = newp->lowmark, i = 0; i < LWP_REDZONE / sizeof(long);
514 if (*lp == LWP_CHECKMARK)
516 /* Stack underflow. */
519 while (i < LWP_REDZONE / sizeof(long)) {
520 if (*lp++ != LWP_CHECKMARK)
524 amt = (end + 1) * sizeof(long);
526 amt = (LWP_REDZONE - i + 1) * sizeof(long);
528 logerror("Thread %s stack underflow %d bytes (of %u)",
530 newp->size - 2 * LWP_REDZONE - (int)sizeof(stkalign_t));
537 * Figure out how much stack was used by this thread.
540 lwpStackCheckUsed(struct lwpProc *newp)
547 if (!newp || !newp->sbtm)
549 lim = newp->size / sizeof(long);
550 if (growsdown(&marker)) {
551 /* Start at the bottom and find first non checkmark. */
552 for (lp = newp->sbtm, i = 0; i < lim; i++, lp++) {
553 if (*lp != LWP_CHECKMARK) {
558 /* Start at the top and find first non checkmark. */
560 lp += newp->size / sizeof(long);
562 for (i = 0; i < lim; i++, lp--) {
563 if (*lp != LWP_CHECKMARK) {
568 lwpStatus(newp, "Thread stack %lu used %lu left %lu total",
569 labs((char *)lp - (char *)newp->lowmark) - LWP_REDZONE,
570 labs((char *)newp->himark - (char *)lp) - LWP_REDZONE,
571 labs((char *)newp->himark - (char *)newp->lowmark) - LWP_REDZONE);