ref: 4983641c3ef57d10a9433a18ecff2116eae09375
dir: /exportfs/exportfs.c/
/* * exportfs - Export a plan 9 name space across a network */ #include <u.h> #include <libc.h> #include <fcall.h> #include <libsec.h> #include "drawterm.h" #define Extern #include "exportfs.h" /* #define QIDPATH ((1LL<<48)-1) */ #define QIDPATH ((((vlong)1)<<48)-1) vlong newqid = 0; void (*fcalls[256])(Fsrpc*); /* accounting and debugging counters */ int filecnt; int freecnt; int qidcnt; int qfreecnt; int ncollision; int netfd; int exportfs(int fd) { char buf[ERRMAX], ebuf[ERRMAX]; Fsrpc *r; int i, n; fcalls[Tversion] = Xversion; fcalls[Tauth] = Xauth; fcalls[Tflush] = Xflush; fcalls[Tattach] = Xattach; fcalls[Twalk] = Xwalk; fcalls[Topen] = slave; fcalls[Tcreate] = Xcreate; fcalls[Tclunk] = Xclunk; fcalls[Tread] = slave; fcalls[Twrite] = slave; fcalls[Tremove] = Xremove; fcalls[Tstat] = Xstat; fcalls[Twstat] = Xwstat; srvfd = -1; netfd = fd; //dbg = 1; strcpy(buf, "this is buf"); strcpy(ebuf, "this is ebuf"); DEBUG(DFD, "exportfs: started\n"); // rfork(RFNOTEG); messagesize = iounit(netfd); if(messagesize == 0) messagesize = 8192+IOHDRSZ; Workq = emallocz(sizeof(Fsrpc)*Nr_workbufs); // for(i=0; i<Nr_workbufs; i++) // Workq[i].buf = emallocz(messagesize); fhash = emallocz(sizeof(Fid*)*FHASHSIZE); fmtinstall('F', fcallfmt); initroot(); DEBUG(DFD, "exportfs: %s\n", buf); /* * Start serving file requests from the network */ for(;;) { r = getsbuf(); if(r == 0) fatal("Out of service buffers"); DEBUG(DFD, "read9p..."); n = read9pmsg(netfd, r->buf, messagesize); if(n <= 0) fatal(nil); if(convM2S(r->buf, n, &r->work) == 0){ iprint("convM2S %d byte message\n", n); for(i=0; i<n; i++){ iprint(" %.2ux", r->buf[i]); if(i%16 == 15) iprint("\n"); } if(i%16) iprint("\n"); fatal("convM2S format error"); } if(0) iprint("<- %F\n", &r->work); DEBUG(DFD, "%F\n", &r->work); (fcalls[r->work.type])(r); } } void reply(Fcall *r, Fcall *t, char *err) { uchar *data; int m, n; t->tag = r->tag; t->fid = r->fid; if(err) { t->type = Rerror; t->ename = err; } else t->type = r->type + 1; if(0) iprint("-> %F\n", t); DEBUG(DFD, "\t%F\n", t); data = malloc(messagesize); /* not mallocz; no need to clear */ if(data == nil) fatal(Enomem); n = convS2M(t, data, messagesize); if((m=write(netfd, data, n))!=n){ iprint("wrote %d got %d (%r)\n", n, m); fatal("write"); } free(data); } Fid * getfid(int nr) { Fid *f; for(f = fidhash(nr); f; f = f->next) if(f->nr == nr) return f; return 0; } int freefid(int nr) { Fid *f, **l; char buf[128]; l = &fidhash(nr); for(f = *l; f; f = f->next) { if(f->nr == nr) { if(f->mid) { sprint(buf, "/mnt/exportfs/%d", f->mid); unmount(0, buf); psmap[f->mid] = 0; } if(f->f) { freefile(f->f); f->f = nil; } *l = f->next; f->next = fidfree; fidfree = f; return 1; } l = &f->next; } return 0; } Fid * newfid(int nr) { Fid *new, **l; int i; l = &fidhash(nr); for(new = *l; new; new = new->next) if(new->nr == nr) return 0; if(fidfree == 0) { fidfree = emallocz(sizeof(Fid) * Fidchunk); for(i = 0; i < Fidchunk-1; i++) fidfree[i].next = &fidfree[i+1]; fidfree[Fidchunk-1].next = 0; } new = fidfree; fidfree = new->next; memset(new, 0, sizeof(Fid)); new->next = *l; *l = new; new->nr = nr; new->fid = -1; new->mid = 0; return new; } Fsrpc * getsbuf(void) { static int ap; int look, rounds; Fsrpc *wb; int small_instead_of_fast = 1; if(small_instead_of_fast) ap = 0; /* so we always start looking at the beginning and reuse buffers */ for(rounds = 0; rounds < 10; rounds++) { for(look = 0; look < Nr_workbufs; look++) { if(++ap == Nr_workbufs) ap = 0; if(Workq[ap].busy == 0) break; } if(look == Nr_workbufs){ sleep(10 * rounds); continue; } wb = &Workq[ap]; wb->pid = 0; wb->canint = 0; wb->flushtag = NOTAG; wb->busy = 1; if(wb->buf == nil) /* allocate buffers dynamically to keep size down */ wb->buf = emallocz(messagesize); return wb; } fatal("No more work buffers"); return nil; } void freefile(File *f) { File *parent, *child; Loop: f->ref--; if(f->ref > 0) return; freecnt++; if(f->ref < 0) abort(); DEBUG(DFD, "free %s\n", f->name); /* delete from parent */ parent = f->parent; if(parent->child == f) parent->child = f->childlist; else{ for(child=parent->child; child->childlist!=f; child=child->childlist) if(child->childlist == nil) fatal("bad child list"); child->childlist = f->childlist; } freeqid(f->qidt); free(f->name); f->name = nil; free(f); f = parent; if(f != nil) goto Loop; } File * file(File *parent, char *name) { Dir *dir; char *path; File *f; DEBUG(DFD, "\tfile: 0x%p %s name %s\n", parent, parent->name, name); path = makepath(parent, name); dir = dirstat(path); free(path); if(dir == nil) return nil; for(f = parent->child; f; f = f->childlist) if(strcmp(name, f->name) == 0) break; if(f == nil){ f = emallocz(sizeof(File)); f->name = estrdup(name); f->parent = parent; f->childlist = parent->child; parent->child = f; parent->ref++; f->ref = 0; filecnt++; } f->ref++; f->qid.type = dir->qid.type; f->qid.vers = dir->qid.vers; f->qidt = uniqueqid(dir); f->qid.path = f->qidt->uniqpath; f->inval = 0; free(dir); return f; } void initroot(void) { Dir *dir; root = emallocz(sizeof(File)); root->name = estrdup("."); dir = dirstat(root->name); if(dir == nil) fatal("root stat"); root->ref = 1; root->qid.vers = dir->qid.vers; root->qidt = uniqueqid(dir); root->qid.path = root->qidt->uniqpath; root->qid.type = QTDIR; free(dir); psmpt = emallocz(sizeof(File)); psmpt->name = estrdup("/"); dir = dirstat(psmpt->name); if(dir == nil) return; psmpt->ref = 1; psmpt->qid.vers = dir->qid.vers; psmpt->qidt = uniqueqid(dir); psmpt->qid.path = psmpt->qidt->uniqpath; free(dir); psmpt = file(psmpt, "mnt"); if(psmpt == 0) return; psmpt = file(psmpt, "exportfs"); } char* makepath(File *p, char *name) { int i, n; char *c, *s, *path, *seg[256]; seg[0] = name; n = strlen(name)+2; for(i = 1; i < 256 && p; i++, p = p->parent){ seg[i] = p->name; n += strlen(p->name)+1; } path = malloc(n); if(path == nil) fatal("out of memory"); s = path; while(i--) { for(c = seg[i]; *c; c++) *s++ = *c; *s++ = '/'; } while(s[-1] == '/') s--; *s = '\0'; return path; } int qidhash(vlong path) { int h, n; h = 0; for(n=0; n<64; n+=Nqidbits){ h ^= path; path >>= Nqidbits; } return h & (Nqidtab-1); } void freeqid(Qidtab *q) { ulong h; Qidtab *l; q->ref--; if(q->ref > 0) return; qfreecnt++; h = qidhash(q->path); if(qidtab[h] == q) qidtab[h] = q->next; else{ for(l=qidtab[h]; l->next!=q; l=l->next) if(l->next == nil) fatal("bad qid list"); l->next = q->next; } free(q); } Qidtab* qidlookup(Dir *d) { ulong h; Qidtab *q; h = qidhash(d->qid.path); for(q=qidtab[h]; q!=nil; q=q->next) if(q->type==d->type && q->dev==d->dev && q->path==d->qid.path) return q; return nil; } int qidexists(vlong path) { int h; Qidtab *q; for(h=0; h<Nqidtab; h++) for(q=qidtab[h]; q!=nil; q=q->next) if(q->uniqpath == path) return 1; return 0; } Qidtab* uniqueqid(Dir *d) { ulong h; vlong path; Qidtab *q; q = qidlookup(d); if(q != nil){ q->ref++; return q; } path = d->qid.path; while(qidexists(path)){ DEBUG(DFD, "collision on %s\n", d->name); /* collision: find a new one */ ncollision++; path &= QIDPATH; ++newqid; if(newqid >= (1<<16)){ DEBUG(DFD, "collision wraparound\n"); newqid = 1; } path |= newqid<<48; DEBUG(DFD, "assign qid %.16llux\n", path); } q = mallocz(sizeof(Qidtab), 1); if(q == nil) fatal("no memory for qid table"); qidcnt++; q->ref = 1; q->type = d->type; q->dev = d->dev; q->path = d->qid.path; q->uniqpath = path; h = qidhash(d->qid.path); q->next = qidtab[h]; qidtab[h] = q; return q; } void fatal(char *s, ...) { char buf[ERRMAX]; va_list arg; if (s != nil) { va_start(arg, s); vsnprint(buf, ERRMAX, s, arg); va_end(arg); } /* Clear away the slave children */ // for(m = Proclist; m; m = m->next) // postnote(PNPROC, m->pid, "kill"); if (s != nil) { DEBUG(DFD, "%s\n", buf); sysfatal("%s", buf); } else exits(nil); }