ref: ad37339a1c39c90f51d273abe60f552d3900f752
dir: /sys/src/cmd/exportfs/io.c/
#include <u.h> #include <libc.h> #include <fcall.h> #define Extern #include "exportfs.h" #define QIDPATH ((1LL<<48)-1) vlong newqid = 0; void (*fcalls[])(Fsrpc*) = { [Tversion] Xversion, [Tauth] Xauth, [Tflush] Xflush, [Tattach] Xattach, [Twalk] Xwalk, [Topen] slave, [Tcreate] Xcreate, [Tclunk] Xclunk, [Tread] slave, [Twrite] slave, [Tremove] Xremove, [Tstat] Xstat, [Twstat] Xwstat, }; /* accounting and debugging counters */ int filecnt; int freecnt; int qidcnt; int qfreecnt; int ncollision; /* * Start serving file requests from the network */ void io(void) { Fsrpc *r; int n; for(;;) { r = getsbuf(); n = read9pmsg(0, r->buf, messagesize); if(n <= 0) fatal(nil); if(convM2S(r->buf, n, &r->work) != n) fatal("convM2S format error"); DEBUG(DFD, "%F\n", &r->work); (fcalls[r->work.type])(r); } } void reply(Fcall *r, Fcall *t, char *err) { uchar *data; int n; t->tag = r->tag; t->fid = r->fid; if(err != nil) { t->type = Rerror; t->ename = err; } else t->type = r->type + 1; 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(write(1, data, n) != n){ /* not fatal, might have got a note due to flush */ fprint(2, "exportfs: short write in reply: %r\n"); } free(data); } void mounterror(char *err) { Fsrpc *r; int n; r = getsbuf(); r->work.tag = NOTAG; r->work.fid = NOFID; r->work.type = Rerror; r->work.ename = err; n = convS2M(&r->work, r->buf, messagesize); write(1, r->buf, n); exits(err); } Fid * getfid(int nr) { Fid *f; for(f = fidhash(nr); f != nil; f = f->next) if(f->nr == nr) return f; return nil; } int freefid(int nr) { Fid *f, **l; char buf[128]; l = &fidhash(nr); for(f = *l; f != nil; f = f->next) { if(f->nr == nr) { if(f->mid) { snprint(buf, sizeof(buf), "/mnt/exportfs/%d", f->mid); unmount(0, buf); psmap[f->mid] = 0; } if(f->f != nil) { freefile(f->f); f->f = nil; } if(f->dir != nil){ free(f->dir); f->dir = 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 != nil; new = new->next) if(new->nr == nr) return nil; if(fidfree == nil) { fidfree = emallocz(sizeof(Fid) * Fidchunk); for(i = 0; i < Fidchunk-1; i++) fidfree[i].next = &fidfree[i+1]; fidfree[Fidchunk-1].next = nil; } 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; } static struct { Lock; Fsrpc *free; /* statistics */ int nalloc; int nfree; } sbufalloc; Fsrpc * getsbuf(void) { Fsrpc *w; lock(&sbufalloc); w = sbufalloc.free; if(w != nil){ sbufalloc.free = w->next; w->next = nil; sbufalloc.nfree--; unlock(&sbufalloc); } else { sbufalloc.nalloc++; unlock(&sbufalloc); w = emallocz(sizeof(*w) + messagesize); } w->flushtag = NOTAG; return w; } void putsbuf(Fsrpc *w) { w->flushtag = NOTAG; lock(&sbufalloc); w->next = sbufalloc.free; sbufalloc.free = w; sbufalloc.nfree++; unlock(&sbufalloc); } void freefile(File *f) { File *parent, *child; while(--f->ref == 0){ freecnt++; 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); free(f); f = parent; } } 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); if(patternfile != nil && excludefile(path)){ free(path); return nil; } dir = dirstat(path); free(path); if(dir == nil) return nil; for(f = parent->child; f != nil; 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 == nil) 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 = emallocz(n); 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; if(--q->ref) 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); } qidcnt++; q = emallocz(sizeof(Qidtab)); 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; Proc *m; if(s != nil) { va_start(arg, s); vsnprint(buf, ERRMAX, s, arg); va_end(arg); } /* Clear away the slave children */ for(m = Proclist; m != nil; m = m->next) postnote(PNPROC, m->pid, "kill"); if(s != nil) { DEBUG(DFD, "%s\n", buf); sysfatal("%s", buf); /* caution: buf could contain '%' */ } else exits(nil); } void* emallocz(uint n) { void *p; p = mallocz(n, 1); if(p == nil) fatal(Enomem); setmalloctag(p, getcallerpc(&n)); return p; } char* estrdup(char *s) { char *t; t = strdup(s); if(t == nil) fatal(Enomem); setmalloctag(t, getcallerpc(&s)); return t; }