Markus Armbruster
aee8272d3d
Give draw_map(), xdeval(), LwpSchedQ[], LwpDeadQ, LwpContextPtr, LwpMaxpri, LwpStackGrowsDown internal linkage.
407 lines
9.6 KiB
C
407 lines
9.6 KiB
C
/*
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* Empire - A multi-player, client/server Internet based war game.
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* Copyright (C) 1994-2008, Dave Pare, Jeff Bailey, Thomas Ruschak,
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* Ken Stevens, Steve McClure
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* Copyright (C) 1991-3 Stephen Crane
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* ---
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*
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* See files README, COPYING and CREDITS in the root of the source
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* tree for related information and legal notices. It is expected
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* that future projects/authors will amend these files as needed.
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*
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* ---
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*
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* lwp.c: lightweight process creation, destruction and manipulation
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*
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* Known contributors to this file:
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* Markus Armbruster, 2004-2008
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*/
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#include <config.h>
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#include <string.h>
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#include "lwp.h"
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#include "lwpint.h"
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#include "prototypes.h"
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static struct lwpQueue LwpSchedQ[LWP_MAX_PRIO], LwpDeadQ;
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struct lwpProc *LwpCurrent = NULL;
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static void **LwpContextPtr;
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static int LwpMaxpri = 0; /* maximum priority so far */
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static int LwpStackGrowsDown;
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static void lwpDestroy(struct lwpProc *proc);
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static void lwpStackCheckInit(struct lwpProc *newp);
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static void lwpStackCheck(struct lwpProc *newp);
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static void lwpStackCheckUsed(struct lwpProc *newp);
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/* check stack direction */
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static int
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growsdown(void *x)
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{
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int y;
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y = (x > (void *)&y);
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return y;
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}
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/*
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* lwpReschedule -- schedule another process. we also check for dead
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* processes here and free them.
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*/
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void
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lwpReschedule(void)
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{
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static struct lwpProc *nextp;
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static int i;
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if (LwpCurrent && (LwpCurrent->flags & LWP_STACKCHECK)) {
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lwpStackCheck(LwpCurrent);
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}
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lwpSigWakeup();
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lwpWakeupSleep();
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/* destroy dead threads */
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lwpStatus(LwpCurrent, "Cleaning dead queue");
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while (NULL != (nextp = lwpGetFirst(&LwpDeadQ))) {
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if (CANT_HAPPEN(nextp == LwpCurrent))
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abort();
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lwpDestroy(nextp);
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lwpStatus(LwpCurrent, "Destroying done");
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}
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for (i = LwpMaxpri + 1; i--;) {
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while (NULL != (nextp = lwpGetFirst(&LwpSchedQ[i]))) {
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if (!nextp->dead)
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break;
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/* clean up after dead bodies */
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lwpStatus(nextp, "got a dead body");
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if (nextp == LwpCurrent) {
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lwpStatus(nextp, "we are in it -- will bury later");
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lwpAddTail(&LwpDeadQ, nextp);
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} else {
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lwpDestroy(nextp);
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}
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nextp = 0;
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}
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if (nextp)
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break;
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}
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if (CANT_HAPPEN(LwpCurrent == 0 && nextp == 0))
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abort();
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if (LwpCurrent != nextp) {
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struct lwpProc *oldp = LwpCurrent;
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if (oldp)
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lwpStatus(oldp, "switch out");
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LwpCurrent = nextp;
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*LwpContextPtr = nextp->ud;
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lwpSwitchContext(oldp, nextp);
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lwpStatus(nextp, "switch in %d", nextp->pri);
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}
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}
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/*
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* lwpEntryPoint -- process entry point.
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*/
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void
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lwpEntryPoint(void)
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{
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lwpStatus(LwpCurrent, "starting at entry point");
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(*LwpCurrent->entry)(LwpCurrent->ud);
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lwpExit();
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}
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static int
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lwpNewStack(struct lwpProc *newp, int stacksz)
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{
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char *s;
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int size, redsize;
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/* Make size a multiple of sizeof(long) to keep things aligned */
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stacksz = (stacksz + sizeof(long) - 1) & -sizeof(long);
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/* Add a red zone on each side of the stack for LWP_STACKCHECK */
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redsize = newp->flags & LWP_STACKCHECK ? LWP_REDZONE : 0;
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size = stacksz + 2 * redsize;
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s = malloc(size);
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if (!s)
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return -1;
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newp->sbtm = s;
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newp->size = size;
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newp->ustack = s + redsize;
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newp->usize = stacksz;
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if (newp->flags & LWP_STACKCHECK)
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lwpStackCheckInit(newp);
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return 0;
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}
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/*
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* lwpCreate -- create a process.
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*/
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struct lwpProc *
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lwpCreate(int priority, void (*entry)(void *), int stacksz,
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int flags, char *name, int argc, char **argv, void *ud)
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{
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struct lwpProc *newp;
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if (!(newp = malloc(sizeof(struct lwpProc))))
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return NULL;
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newp->flags = flags;
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newp->name = strdup(name);
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newp->entry = entry;
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newp->argc = argc;
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newp->argv = argv;
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newp->ud = ud;
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newp->dead = 0;
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newp->runtime = (time_t)-1;
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newp->fd = -1;
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newp->sbtm = NULL;
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if (LWP_MAX_PRIO <= priority)
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priority = LWP_MAX_PRIO - 1;
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if (LwpMaxpri < (newp->pri = priority))
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LwpMaxpri = priority;
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if (lwpNewStack(newp, stacksz) < 0 || lwpNewContext(newp) < 0) {
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free(newp->sbtm);
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free(newp->name);
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free(newp);
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return NULL;
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}
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lwpStatus(newp, "creating process structure %p (sbtm %p)",
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newp, newp->sbtm);
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lwpReady(newp);
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lwpReady(LwpCurrent);
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lwpReschedule();
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return newp;
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}
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static void
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lwpDestroy(struct lwpProc *proc)
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{
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if (proc->flags & LWP_STACKCHECK) {
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lwpStackCheckUsed(proc);
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lwpStackCheck(proc);
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}
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lwpStatus(proc, "destroying sbtm: %p", proc->sbtm);
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free(proc->sbtm);
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free(proc->name);
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free(proc);
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}
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/*
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* lwpReady -- put process on ready queue. if null, assume current.
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*/
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void
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lwpReady(struct lwpProc *p)
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{
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if (!p)
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p = LwpCurrent;
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lwpStatus(p, "added to run queue");
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lwpAddTail(&LwpSchedQ[p->pri], p);
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}
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/*
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* return user's data
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*/
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void *
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lwpGetUD(struct lwpProc *p)
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{
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if (!p)
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p = LwpCurrent;
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return p->ud;
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}
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/*
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* set user's data
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*/
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void
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lwpSetUD(struct lwpProc *p, char *ud)
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{
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if (!p)
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p = LwpCurrent;
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p->ud = ud;
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}
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/*
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* lwpYield -- yield the processor to another thread.
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*/
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void
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lwpYield(void)
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{
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lwpStatus(LwpCurrent, "yielding control");
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lwpReady(LwpCurrent);
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lwpReschedule();
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}
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/*
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* cause the current process to be scheduled for deletion.
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*/
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void
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lwpExit(void)
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{
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lwpStatus(LwpCurrent, "marking self as dead");
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LwpCurrent->dead = 1;
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lwpYield();
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}
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/*
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* mark another process as dead, so it will never be rescheduled.
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* remove any lingering FD action
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*/
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void
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lwpTerminate(struct lwpProc *p)
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{
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lwpStatus(p, "terminating process");
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p->dead = 1;
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lwpWakeup(p);
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}
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/*
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* set the thread's priority, returning the old.
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* if the new priority is lower than the old, we reschedule.
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*/
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int
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lwpSetPriority(int new)
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{
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int old = LwpCurrent->pri;
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if (LWP_MAX_PRIO <= new)
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new = LWP_MAX_PRIO - 1;
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if (LwpMaxpri < new)
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LwpMaxpri = new;
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LwpCurrent->pri = new;
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lwpStatus(LwpCurrent, "resetting priority (%d -> %d)", old, new);
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if (new < old)
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lwpYield();
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return old;
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}
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/*
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* initialise the coroutine structures
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*/
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struct lwpProc *
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lwpInitSystem(int pri, void **ctxptr, int flags, sigset_t *waitset)
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{
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struct lwpQueue *q;
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int i, *stack, marker;
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struct lwpProc *sel;
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LwpContextPtr = ctxptr;
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if (pri < 1)
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pri = 1;
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LwpStackGrowsDown = growsdown(&marker);
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if (!(LwpCurrent = calloc(1, sizeof(struct lwpProc))))
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return NULL;
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if (!(stack = malloc(64)))
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return NULL;
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if (LWP_MAX_PRIO <= pri)
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pri = LWP_MAX_PRIO - 1;
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if (LwpMaxpri < pri)
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LwpMaxpri = pri;
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LwpCurrent->next = 0;
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LwpCurrent->sbtm = stack; /* dummy stack for "main" */
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LwpCurrent->pri = pri;
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LwpCurrent->dead = 0;
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LwpCurrent->flags = flags & ~LWP_STACKCHECK;
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LwpCurrent->name = "Main";
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for (i = LWP_MAX_PRIO, q = LwpSchedQ; i--; q++)
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q->head = q->tail = 0;
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LwpDeadQ.head = LwpDeadQ.tail = 0;
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lwpInitSigWait(waitset);
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/* must be lower in priority than us for this to work right */
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sel = lwpCreate(0, lwpSelect, 16384, flags, "EventHandler", 0, 0, 0);
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lwpInitSelect(sel);
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return LwpCurrent;
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}
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/* lwpStackCheckInit
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*
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* Initialize the entire stack (including both redzones) with the stack
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* check mark. Thus, we can get some indication of how much stack was
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* used.
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*/
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static void
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lwpStackCheckInit(struct lwpProc *newp)
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{
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int *p;
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int *lim = (int *)((char *)newp->sbtm + newp->size);
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for (p = newp->sbtm; p < lim; p++)
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*p = LWP_CHECKMARK;
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}
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/* lwpStackCheck
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*
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* Check if the thread has overflowed/underflowed its stack.
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* Should that happen, abort the process, as we cannot recover.
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*/
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static void
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lwpStackCheck(struct lwpProc *newp)
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{
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int *btm = (int *)(newp->ustack - LWP_REDZONE);
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int *top = (int *)(newp->ustack + newp->usize + LWP_REDZONE);
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int n = LWP_REDZONE / sizeof(int);
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int i, lo_clean, hi_clean, overflow, underflow;
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for (i = 0; i < n && btm[i] == LWP_CHECKMARK; i++) ;
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lo_clean = i;
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for (i = 1; i <= n && top[-i] == LWP_CHECKMARK; i++) ;
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hi_clean = i - 1;
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if (LwpStackGrowsDown) {
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overflow = n - lo_clean;
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underflow = n - hi_clean;
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} else {
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overflow = n - hi_clean;
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underflow = n - lo_clean;
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}
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if (overflow)
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logerror("Thread %s stack overflow %d bytes",
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newp->name, overflow * (int)sizeof(int));
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if (underflow)
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logerror("Thread %s stack underflow %d bytes",
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newp->name, underflow * (int)sizeof(int));
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if (overflow || underflow)
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abort();
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}
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/* lwpStackCheckUsed
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*
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* Figure out how much stack was used by this thread.
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*/
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static void
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lwpStackCheckUsed(struct lwpProc *newp)
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{
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int *base = (int *)newp->ustack;
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int *lim = (int *)(newp->ustack + newp->usize);
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int total = (lim + 1 - base) * sizeof(int);
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int used, *p;
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if (LwpStackGrowsDown) {
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for (p = base; p < lim && *p == LWP_CHECKMARK; ++p) ;
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used = (lim - p) * sizeof(int);
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} else {
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for (p = lim - 1; p >= base && *p == LWP_CHECKMARK; --p) ;
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used = (p - base + 1) * sizeof(int);
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}
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lwpStatus(newp, "Thread stack %d used, %d left, %d total",
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used, total - used, total);
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}
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