sed: Can't open /usr/web/plan9/sources.html #include "u.h" #include "tos.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" #include "../port/edf.h" #include <a.out.h> int shargs(char*, int, char**); extern void checkpages(void); extern void checkpagerefs(void); long sysr1(ulong*) { checkpagerefs(); return 0; } long sysrfork(ulong *arg) { Proc *p; int n, i; Fgrp *ofg; Pgrp *opg; Rgrp *org; Egrp *oeg; ulong pid, flag; Mach *wm; flag = arg[0]; /* Check flags before we commit */ if((flag & (RFFDG|RFCFDG)) == (RFFDG|RFCFDG)) error(Ebadarg); if((flag & (RFNAMEG|RFCNAMEG)) == (RFNAMEG|RFCNAMEG)) error(Ebadarg); if((flag & (RFENVG|RFCENVG)) == (RFENVG|RFCENVG)) error(Ebadarg); if((flag&RFPROC) == 0) { if(flag & (RFMEM|RFNOWAIT)) error(Ebadarg); if(flag & (RFFDG|RFCFDG)) { ofg = up->fgrp; if(flag & RFFDG) up->fgrp = dupfgrp(ofg); else up->fgrp = dupfgrp(nil); closefgrp(ofg); } if(flag & (RFNAMEG|RFCNAMEG)) { opg = up->pgrp; up->pgrp = newpgrp(); if(flag & RFNAMEG) pgrpcpy(up->pgrp, opg); /* inherit noattach */ up->pgrp->noattach = opg->noattach; closepgrp(opg); } if(flag & RFNOMNT) up->pgrp->noattach = 1; if(flag & RFREND) { org = up->rgrp; up->rgrp = newrgrp(); closergrp(org); } if(flag & (RFENVG|RFCENVG)) { oeg = up->egrp; up->egrp = smalloc(sizeof(Egrp)); up->egrp->ref = 1; if(flag & RFENVG) envcpy(up->egrp, oeg); closeegrp(oeg); } if(flag & RFNOTEG) up->noteid = incref(&noteidalloc); return 0; } p = newproc(); p->fpsave = up->fpsave; p->scallnr = up->scallnr; p->s = up->s; p->nerrlab = 0; p->slash = up->slash; p->dot = up->dot; incref(p->dot); memmove(p->note, up->note, sizeof(p->note)); p->privatemem = up->privatemem; p->noswap = up->noswap; p->nnote = up->nnote; p->notified = 0; p->lastnote = up->lastnote; p->notify = up->notify; p->ureg = up->ureg; p->dbgreg = 0; /* Make a new set of memory segments */ n = flag & RFMEM; qlock(&p->seglock); if(waserror()){ qunlock(&p->seglock); nexterror(); } for(i = 0; i < NSEG; i++) if(up->seg[i]) p->seg[i] = dupseg(up->seg, i, n); qunlock(&p->seglock); poperror(); /* File descriptors */ if(flag & (RFFDG|RFCFDG)) { if(flag & RFFDG) p->fgrp = dupfgrp(up->fgrp); else p->fgrp = dupfgrp(nil); } else { p->fgrp = up->fgrp; incref(p->fgrp); } /* Process groups */ if(flag & (RFNAMEG|RFCNAMEG)) { p->pgrp = newpgrp(); if(flag & RFNAMEG) pgrpcpy(p->pgrp, up->pgrp); /* inherit noattach */ p->pgrp->noattach = up->pgrp->noattach; } else { p->pgrp = up->pgrp; incref(p->pgrp); } if(flag & RFNOMNT) p->pgrp->noattach = 1; if(flag & RFREND) p->rgrp = newrgrp(); else { incref(up->rgrp); p->rgrp = up->rgrp; } /* Environment group */ if(flag & (RFENVG|RFCENVG)) { p->egrp = smalloc(sizeof(Egrp)); p->egrp->ref = 1; if(flag & RFENVG) envcpy(p->egrp, up->egrp); } else { p->egrp = up->egrp; incref(p->egrp); } p->hang = up->hang; p->procmode = up->procmode; /* Craft a return frame which will cause the child to pop out of * the scheduler in user mode with the return register zero */ forkchild(p, up->dbgreg); p->parent = up; p->parentpid = up->pid; if(flag&RFNOWAIT) p->parentpid = 0; else { lock(&up->exl); up->nchild++; unlock(&up->exl); } if((flag&RFNOTEG) == 0) p->noteid = up->noteid; /* don't penalize the child, it hasn't done FP in a note handler. */ p->fpstate = up->fpstate & ~FPillegal; pid = p->pid; memset(p->time, 0, sizeof(p->time)); p->time[TReal] = MACHP(0)->ticks; kstrdup(&p->text, up->text); kstrdup(&p->user, up->user); /* * since the bss/data segments are now shareable, * any mmu info about this process is now stale * (i.e. has bad properties) and has to be discarded. */ flushmmu(); p->basepri = up->basepri; p->priority = up->basepri; p->fixedpri = up->fixedpri; p->mp = up->mp; wm = up->wired; if(wm) procwired(p, wm->machno); ready(p); sched(); return pid; } ulong l2be(long l) { uchar *cp; cp = (uchar*)&l; return (cp[0]<<24) | (cp[1]<<16) | (cp[2]<<8) | cp[3]; } long sysexec(ulong *arg) { Segment *s, *ts; ulong t, d, b; int i; Chan *tc; char **argv, **argp; char *a, *charp, *args, *file, *file0; char *progarg[sizeof(Exec)/2+1], *elem, progelem[64]; ulong ssize, spage, nargs, nbytes, n, bssend; int indir; Exec exec; char line[sizeof(Exec)]; Fgrp *f; Image *img; ulong magic, text, entry, data, bss; Tos *tos; indir = 0; elem = nil; validaddr(arg[0], 1, 0); file0 = validnamedup((char*)arg[0], 1); if(waserror()){ free(file0); free(elem); nexterror(); } file = file0; for(;;){ tc = namec(file, Aopen, OEXEC, 0); if(waserror()){ cclose(tc); nexterror(); } if(!indir) kstrdup(&elem, up->genbuf); n = devtab[tc->type]->read(tc, &exec, sizeof(Exec), 0); if(n < 2) error(Ebadexec); magic = l2be(exec.magic); text = l2be(exec.text); entry = l2be(exec.entry); if(n==sizeof(Exec) && (magic == AOUT_MAGIC)){ if(text >= USTKTOP-UTZERO || entry < UTZERO+sizeof(Exec) || entry >= UTZERO+sizeof(Exec)+text) error(Ebadexec); break; /* for binary */ } /* * Process #! /bin/sh args ... */ memmove(line, &exec, sizeof(Exec)); if(indir || line[0]!='#' || line[1]!='!') error(Ebadexec); n = shargs(line, n, progarg); if(n == 0) error(Ebadexec); indir = 1; /* * First arg becomes complete file name */ progarg[n++] = file; progarg[n] = 0; validaddr(arg[1], BY2WD, 1); arg[1] += BY2WD; file = progarg[0]; if(strlen(elem) >= sizeof progelem) error(Ebadexec); strcpy(progelem, elem); progarg[0] = progelem; poperror(); cclose(tc); } data = l2be(exec.data); bss = l2be(exec.bss); t = UTROUND(UTZERO+sizeof(Exec)+text); d = (t + data + (BY2PG-1)) & ~(BY2PG-1); bssend = t + data + bss; b = (bssend + (BY2PG-1)) & ~(BY2PG-1); if(t >= KZERO || d >= KZERO || b >= KZERO) error(Ebadexec); /* * Args: pass 1: count */ nbytes = sizeof(Tos); /* hole for profiling clock at top of stack (and more) */ nargs = 0; if(indir){ argp = progarg; while(*argp){ a = *argp++; nbytes += strlen(a) + 1; nargs++; } } validalign(arg[1], sizeof(char**)); argp = (char**)arg[1]; validaddr((ulong)argp, BY2WD, 0); while(*argp){ a = *argp++; if(((ulong)argp&(BY2PG-1)) < BY2WD) validaddr((ulong)argp, BY2WD, 0); validaddr((ulong)a, 1, 0); nbytes += ((char*)vmemchr(a, 0, 0x7FFFFFFF) - a) + 1; nargs++; } ssize = BY2WD*(nargs+1) + ((nbytes+(BY2WD-1)) & ~(BY2WD-1)); /* * 8-byte align SP for those (e.g. sparc) that need it. * execregs() will subtract another 4 bytes for argc. */ if((ssize+4) & 7) ssize += 4; spage = (ssize+(BY2PG-1)) >> PGSHIFT; /* * Build the stack segment, putting it in kernel virtual for the moment */ if(spage > TSTKSIZ) error(Enovmem); qlock(&up->seglock); if(waserror()){ qunlock(&up->seglock); nexterror(); } up->seg[ESEG] = newseg(SG_STACK, TSTKTOP-USTKSIZE, USTKSIZE/BY2PG); /* * Args: pass 2: assemble; the pages will be faulted in */ tos = (Tos*)(TSTKTOP - sizeof(Tos)); tos->cyclefreq = m->cyclefreq; cycles((uvlong*)&tos->pcycles); tos->pcycles = -tos->pcycles; tos->kcycles = tos->pcycles; tos->clock = 0; argv = (char**)(TSTKTOP - ssize); charp = (char*)(TSTKTOP - nbytes); args = charp; if(indir) argp = progarg; else argp = (char**)arg[1]; for(i=0; i<nargs; i++){ if(indir && *argp==0) { indir = 0; argp = (char**)arg[1]; } *argv++ = charp + (USTKTOP-TSTKTOP); n = strlen(*argp) + 1; memmove(charp, *argp++, n); charp += n; } free(file0); free(up->text); up->text = elem; elem = nil; /* so waserror() won't free elem */ USED(elem); /* copy args; easiest from new process's stack */ n = charp - args; if(n > 128) /* don't waste too much space on huge arg lists */ n = 128; a = up->args; up->args = nil; free(a); up->args = smalloc(n); memmove(up->args, args, n); if(n>0 && up->args[n-1]!='\0'){ /* make sure last arg is NUL-terminated */ /* put NUL at UTF-8 character boundary */ for(i=n-1; i>0; --i) if(fullrune(up->args+i, n-i)) break; up->args[i] = 0; n = i+1; } up->nargs = n; /* * Committed. * Free old memory. * Special segments are maintained across exec */ for(i = SSEG; i <= BSEG; i++) { putseg(up->seg[i]); /* prevent a second free if we have an error */ up->seg[i] = 0; } for(i = BSEG+1; i < NSEG; i++) { s = up->seg[i]; if(s != 0 && (s->type&SG_CEXEC)) { putseg(s); up->seg[i] = 0; } } /* * Close on exec */ f = up->fgrp; for(i=0; i<=f->maxfd; i++) fdclose(i, CCEXEC); /* Text. Shared. Attaches to cache image if possible */ /* attachimage returns a locked cache image */ img = attachimage(SG_TEXT|SG_RONLY, tc, UTZERO, (t-UTZERO)>>PGSHIFT); ts = img->s; up->seg[TSEG] = ts; ts->flushme = 1; ts->fstart = 0; ts->flen = sizeof(Exec)+text; unlock(img); /* Data. Shared. */ s = newseg(SG_DATA, t, (d-t)>>PGSHIFT); up->seg[DSEG] = s; /* Attached by hand */ incref(img); s->image = img; s->fstart = ts->fstart+ts->flen; s->flen = data; /* BSS. Zero fill on demand */ up->seg[BSEG] = newseg(SG_BSS, d, (b-d)>>PGSHIFT); /* * Move the stack */ s = up->seg[ESEG]; up->seg[ESEG] = 0; up->seg[SSEG] = s; qunlock(&up->seglock); poperror(); /* seglock */ poperror(); /* elem */ s->base = USTKTOP-USTKSIZE; s->top = USTKTOP; relocateseg(s, USTKTOP-TSTKTOP); /* * '/' processes are higher priority (hack to make /ip more responsive). */ if(devtab[tc->type]->dc == L'/') up->basepri = PriRoot; up->priority = up->basepri; poperror(); cclose(tc); /* * At this point, the mmu contains info about the old address * space and needs to be flushed */ flushmmu(); qlock(&up->debug); up->nnote = 0; up->notify = 0; up->notified = 0; up->privatemem = 0; procsetup(up); qunlock(&up->debug); if(up->hang) up->procctl = Proc_stopme; return execregs(entry, ssize, nargs); } int shargs(char *s, int n, char **ap) { int i; s += 2; n -= 2; /* skip #! */ for(i=0; s[i]!='\n'; i++) if(i == n-1) return 0; s[i] = 0; *ap = 0; i = 0; for(;;) { while(*s==' ' || *s=='\t') s++; if(*s == 0) break; i++; *ap++ = s; *ap = 0; while(*s && *s!=' ' && *s!='\t') s++; if(*s == 0) break; else *s++ = 0; } return i; } int return0(void*) { return 0; } long syssleep(ulong *arg) { int n; n = arg[0]; if(n <= 0) { if (up->edf && (up->edf->flags & Admitted)) edfyield(); else yield(); return 0; } if(n < TK2MS(1)) n = TK2MS(1); tsleep(&up->sleep, return0, 0, n); return 0; } long sysalarm(ulong *arg) { return procalarm(arg[0]); } long sysexits(ulong *arg) { char *status; char *inval = "invalid exit string"; char buf[ERRMAX]; status = (char*)arg[0]; if(status){ if(waserror()) status = inval; else{ validaddr((ulong)status, 1, 0); if(vmemchr(status, 0, ERRMAX) == 0){ memmove(buf, status, ERRMAX); buf[ERRMAX-1] = 0; status = buf; } poperror(); } } pexit(status, 1); return 0; /* not reached */ } long sys_wait(ulong *arg) { int pid; Waitmsg w; OWaitmsg *ow; if(arg[0] == 0) return pwait(nil); validaddr(arg[0], sizeof(OWaitmsg), 1); validalign(arg[0], BY2WD); /* who cares? */ pid = pwait(&w); if(pid >= 0){ ow = (OWaitmsg*)arg[0]; readnum(0, ow->pid, NUMSIZE, w.pid, NUMSIZE); readnum(0, ow->time+TUser*NUMSIZE, NUMSIZE, w.time[TUser], NUMSIZE); readnum(0, ow->time+TSys*NUMSIZE, NUMSIZE, w.time[TSys], NUMSIZE); readnum(0, ow->time+TReal*NUMSIZE, NUMSIZE, w.time[TReal], NUMSIZE); strncpy(ow->msg, w.msg, sizeof(ow->msg)); ow->msg[sizeof(ow->msg)-1] = '\0'; } return pid; } long sysawait(ulong *arg) { int i; int pid; Waitmsg w; ulong n; n = arg[1]; validaddr(arg[0], n, 1); pid = pwait(&w); if(pid < 0) return -1; i = snprint((char*)arg[0], n, "%d %lud %lud %lud %q", w.pid, w.time[TUser], w.time[TSys], w.time[TReal], w.msg); return i; } void werrstr(char *fmt, ...) { va_list va; if(up == nil) return; va_start(va, fmt); vseprint(up->syserrstr, up->syserrstr+ERRMAX, fmt, va); va_end(va); } static long generrstr(char *buf, uint nbuf) { char tmp[ERRMAX]; if(nbuf == 0) error(Ebadarg); validaddr((ulong)buf, nbuf, 1); if(nbuf > sizeof tmp) nbuf = sizeof tmp; memmove(tmp, buf, nbuf); /* make sure it's NUL-terminated */ tmp[nbuf-1] = '\0'; memmove(buf, up->syserrstr, nbuf); buf[nbuf-1] = '\0'; memmove(up->syserrstr, tmp, nbuf); return 0; } long syserrstr(ulong *arg) { return generrstr((char*)arg[0], arg[1]); } /* compatibility for old binaries */ long sys_errstr(ulong *arg) { return generrstr((char*)arg[0], 64); } long sysnotify(ulong *arg) { if(arg[0] != 0) validaddr(arg[0], sizeof(ulong), 0); up->notify = (int(*)(void*, char*))(arg[0]); return 0; } long sysnoted(ulong *arg) { if(arg[0]!=NRSTR && !up->notified) error(Egreg); return 0; } long syssegbrk(ulong *arg) { int i; ulong addr; Segment *s; addr = arg[0]; for(i = 0; i < NSEG; i++) { s = up->seg[i]; if(s == 0 || addr < s->base || addr >= s->top) continue; switch(s->type&SG_TYPE) { case SG_TEXT: case SG_DATA: case SG_STACK: error(Ebadarg); default: return ibrk(arg[1], i); } } error(Ebadarg); return 0; /* not reached */ } long syssegattach(ulong *arg) { return segattach(up, arg[0], (char*)arg[1], arg[2], arg[3]); } long syssegdetach(ulong *arg) { int i; ulong addr; Segment *s; qlock(&up->seglock); if(waserror()){ qunlock(&up->seglock); nexterror(); } s = 0; addr = arg[0]; for(i = 0; i < NSEG; i++) if(s = up->seg[i]) { qlock(&s->lk); if((addr >= s->base && addr < s->top) || (s->top == s->base && addr == s->base)) goto found; qunlock(&s->lk); } error(Ebadarg); found: /* * Check we are not detaching the initial stack segment. */ if(s == up->seg[SSEG]){ qunlock(&s->lk); error(Ebadarg); } up->seg[i] = 0; qunlock(&s->lk); putseg(s); qunlock(&up->seglock); poperror(); /* Ensure we flush any entries from the lost segment */ flushmmu(); return 0; } long syssegfree(ulong *arg) { Segment *s; ulong from, to; from = arg[0]; s = seg(up, from, 1); if(s == nil) error(Ebadarg); to = (from + arg[1]) & ~(BY2PG-1); from = PGROUND(from); if(to > s->top) { qunlock(&s->lk); error(Ebadarg); } mfreeseg(s, from, (to - from) / BY2PG); qunlock(&s->lk); flushmmu(); return 0; } /* For binary compatibility */ long sysbrk_(ulong *arg) { return ibrk(arg[0], BSEG); } long sysrendezvous(ulong *arg) { uintptr tag, val; Proc *p, **l; tag = arg[0]; l = &REND(up->rgrp, tag); up->rendval = ~(uintptr)0; lock(up->rgrp); for(p = *l; p; p = p->rendhash) { if(p->rendtag == tag) { *l = p->rendhash; val = p->rendval; p->rendval = arg[1]; while(p->mach != 0) ; ready(p); unlock(up->rgrp); return val; } l = &p->rendhash; } /* Going to sleep here */ up->rendtag = tag; up->rendval = arg[1]; up->rendhash = *l; *l = up; up->state = Rendezvous; unlock(up->rgrp); sched(); return up->rendval; } /* * The implementation of semaphores is complicated by needing * to avoid rescheduling in syssemrelease, so that it is safe * to call from real-time processes. This means syssemrelease * cannot acquire any qlocks, only spin locks. * * Semacquire and semrelease must both manipulate the semaphore * wait list. Lock-free linked lists only exist in theory, not * in practice, so the wait list is protected by a spin lock. * * The semaphore value *addr is stored in user memory, so it * cannot be read or written while holding spin locks. * * Thus, we can access the list only when holding the lock, and * we can access the semaphore only when not holding the lock. * This makes things interesting. Note that sleep's condition function * is called while holding two locks - r and up->rlock - so it cannot * access the semaphore value either. * * An acquirer announces its intention to try for the semaphore * by putting a Sema structure onto the wait list and then * setting Sema.waiting. After one last check of semaphore, * the acquirer sleeps until Sema.waiting==0. A releaser of n * must wake up n acquirers who have Sema.waiting set. It does * this by clearing Sema.waiting and then calling wakeup. * * There are three interesting races here. * The first is that in this particular sleep/wakeup usage, a single * wakeup can rouse a process from two consecutive sleeps! * The ordering is: * * (a) set Sema.waiting = 1 * (a) call sleep * (b) set Sema.waiting = 0 * (a) check Sema.waiting inside sleep, return w/o sleeping * (a) try for semaphore, fail * (a) set Sema.waiting = 1 * (a) call sleep * (b) call wakeup(a) * (a) wake up again * * This is okay - semacquire will just go around the loop * again. It does mean that at the top of the for(;;) loop in * semacquire, phore.waiting might already be set to 1. * * The second is that a releaser might wake an acquirer who is * interrupted before he can acquire the lock. Since * release(n) issues only n wakeup calls -- only n can be used * anyway -- if the interrupted process is not going to use his * wakeup call he must pass it on to another acquirer. * * The third race is similar to the second but more subtle. An * acquirer sets waiting=1 and then does a final canacquire() * before going to sleep. The opposite order would result in * missing wakeups that happen between canacquire and * waiting=1. (In fact, the whole point of Sema.waiting is to * avoid missing wakeups between canacquire() and sleep().) But * there can be spurious wakeups between a successful * canacquire() and the following semdequeue(). This wakeup is * not useful to the acquirer, since he has already acquired * the semaphore. Like in the previous case, though, the * acquirer must pass the wakeup call along. * * This is all rather subtle. The code below has been verified * with the spin model /sys/src/9/port/semaphore.p. The * original code anticipated the second race but not the first * or third, which were caught only with spin. The first race * is mentioned in /sys/doc/sleep.ps, but I'd forgotten about it. * It was lucky that my abstract model of sleep/wakeup still managed * to preserve that behavior. * * I remain slightly concerned about memory coherence * outside of locks. The spin model does not take * queued processor writes into account so we have to * think hard. The only variables accessed outside locks * are the semaphore value itself and the boolean flag * Sema.waiting. The value is only accessed with cmpswap, * whose job description includes doing the right thing as * far as memory coherence across processors. That leaves * Sema.waiting. To handle it, we call coherence() before each * read and after each write. - rsc */ /* Add semaphore p with addr a to list in seg. */ static void semqueue(Segment *s, long *a, Sema *p) { memset(p, 0, sizeof *p); p->addr = a; lock(&s->sema); /* uses s->sema.Rendez.Lock, but no one else is */ p->next = &s->sema; p->prev = s->sema.prev; p->next->prev = p; p->prev->next = p; unlock(&s->sema); } /* Remove semaphore p from list in seg. */ static void semdequeue(Segment *s, Sema *p) { lock(&s->sema); p->next->prev = p->prev; p->prev->next = p->next; unlock(&s->sema); } /* Wake up n waiters with addr a on list in seg. */ static void semwakeup(Segment *s, long *a, long n) { Sema *p; lock(&s->sema); for(p=s->sema.next; p!=&s->sema && n>0; p=p->next){ if(p->addr == a && p->waiting){ p->waiting = 0; coherence(); wakeup(p); n--; } } unlock(&s->sema); } /* Add delta to semaphore and wake up waiters as appropriate. */ static long semrelease(Segment *s, long *addr, long delta) { long value; do value = *addr; while(!cmpswap(addr, value, value+delta)); semwakeup(s, addr, delta); return value+delta; } /* Try to acquire semaphore using compare-and-swap */ static int canacquire(long *addr) { long value; while((value=*addr) > 0) if(cmpswap(addr, value, value-1)) return 1; return 0; } /* Should we wake up? */ static int semawoke(void *p) { coherence(); return !((Sema*)p)->waiting; } /* Acquire semaphore (subtract 1). */ static int semacquire(Segment *s, long *addr, int block) { int acquired; Sema phore; if(canacquire(addr)) return 1; if(!block) return 0; acquired = 0; semqueue(s, addr, &phore); for(;;){ phore.waiting = 1; coherence(); if(canacquire(addr)){ acquired = 1; break; } if(waserror()) break; sleep(&phore, semawoke, &phore); poperror(); } semdequeue(s, &phore); coherence(); /* not strictly necessary due to lock in semdequeue */ if(!phore.waiting) semwakeup(s, addr, 1); if(!acquired) nexterror(); return 1; } /* Acquire semaphore or time-out */ static int tsemacquire(Segment *s, long *addr, ulong ms) { int acquired, timedout; ulong t, elms; Sema phore; if(canacquire(addr)) return 1; if(ms == 0) return 0; acquired = timedout = 0; semqueue(s, addr, &phore); for(;;){ phore.waiting = 1; coherence(); if(canacquire(addr)){ acquired = 1; break; } if(waserror()) break; t = m->ticks; tsleep(&phore, semawoke, &phore, ms); elms = TK2MS(m->ticks - t); poperror(); if(elms >= ms){ timedout = 1; break; } ms -= elms; } semdequeue(s, &phore); coherence(); /* not strictly necessary due to lock in semdequeue */ if(!phore.waiting) semwakeup(s, addr, 1); if(timedout) return 0; if(!acquired) nexterror(); return 1; } long syssemacquire(ulong *arg) { int block; long *addr; Segment *s; validaddr(arg[0], sizeof(long), 1); validalign(arg[0], sizeof(long)); addr = (long*)arg[0]; block = arg[1]; if((s = seg(up, (ulong)addr, 0)) == nil) error(Ebadarg); if(*addr < 0) error(Ebadarg); return semacquire(s, addr, block); } long systsemacquire(ulong *arg) { long *addr; ulong ms; Segment *s; validaddr(arg[0], sizeof(long), 1); validalign(arg[0], sizeof(long)); addr = (long*)arg[0]; ms = arg[1]; if((s = seg(up, (ulong)addr, 0)) == nil) error(Ebadarg); if(*addr < 0) error(Ebadarg); return tsemacquire(s, addr, ms); } long syssemrelease(ulong *arg) { long *addr, delta; Segment *s; validaddr(arg[0], sizeof(long), 1); validalign(arg[0], sizeof(long)); addr = (long*)arg[0]; delta = arg[1]; if((s = seg(up, (ulong)addr, 0)) == nil) error(Ebadarg); /* delta == 0 is a no-op, not a release */ if(delta < 0 || *addr < 0) error(Ebadarg); return semrelease(s, addr, delta); } long sysnsec(ulong *arg) { validaddr(arg[0], sizeof(vlong), 1); validalign(arg[0], sizeof(vlong)); *(vlong*)arg[0] = todget(nil); return 0; } sed: Can't open /usr/web/plan9/sources.html