ref: e51c4bc6e493a9cd0d9e9d7f1d24c57ae77bab65
dir: /sys/src/cmd/skelfs.c/
#include <u.h> #include <libc.h> #include <fcall.h> #include <thread.h> #include <9p.h> typedef struct Skel Skel; struct Skel { char name[64]; char mode; }; static uvlong sessions; static char defmode; enum{ Qroot, Qdir, Qskel, }; #define qtype(x) (((ulong)x)&0x1f) #define qsess(x) ((((ulong)x))>>5) #define mkqid(i,t) ((((ulong)i)<<5)|(t)) static int step(Fid *f, int way, Qid *res, Dir *dp) { Skel *s; int path; char *name; ulong perm; s = f->aux; name = s->name; perm = 0550|DMDIR; path = qtype(f->qid.path) + way; if(!name[0] && way > 0) return -1; if(path < 0) goto Root; switch(path){ Root: case Qroot: name = "/"; /* fallthrough */ case Qdir: res->type = QTDIR; break; case Qskel: switch(s->mode){ case 'd': res->type = QTDIR; break; case 'f': default: res->type = QTFILE; perm = 0; break; } break; default: return -1; } res->vers = qsess(f->qid.path); res->path = mkqid(res->vers, path); if(dp){ dp->mode = perm; dp->name = estrdup9p(name); dp->uid = estrdup9p("sys"); dp->gid = estrdup9p("sys"); dp->qid = *res; dp->length = 0; } return 1; } static int dirgen(int i, Dir *d, void *a) { Fid *f; Qid q; if(i > 0) return -1; f = a; return step(f, 1, &q, d); } static void fidclunk(Fid *fid) { free(fid->aux); } static char* fsclone(Fid *old, Fid *new, void*) { Skel *s, *s2; s = old->aux; s2 = emalloc9p(sizeof *s2); s2->mode = s->mode; utfecpy(s2->name, &s2->name[sizeof s2->name-1], s->name); new->aux = s2; return nil; } static char* fswalk1(Fid *old, char *name, void*) { Skel *s; if(strcmp("..", name) == 0){ step(old, -1, &old->qid, nil); return nil; } s = old->aux; if(!s->name[0] && qtype(old->qid.path) == Qroot && s->mode != 'e'){ utfecpy(s->name, &s->name[sizeof s->name-1], name); old->qid.vers = sessions++; old->qid.path = mkqid(old->qid.vers, qtype(old->qid.path)); } else if(strcmp(name, s->name) != 0) return "does not exist"; if(step(old, 1, &old->qid, nil) < 0) return "does not exist"; return nil; } static void fswalk(Req *r) { walkandclone(r, fswalk1, fsclone, nil); } static void fsattach(Req *r) { Skel s; Fid root; char *spec; Qid *q; spec = r->ifcall.aname; if(spec && spec[0] != '\0') s.mode = spec[0]; else s.mode = defmode; q = &r->fid->qid; q->vers = sessions++; q->path = mkqid(q->vers, Qroot); q->type = QTDIR; r->ofcall.qid = *q; s.name[0] = '\0'; root.aux = &s; respond(r, fsclone(&root, r->fid, nil)); } static void fsstat(Req *r) { Qid q; if(step(r->fid, 0, &q, &r->d) < 0) respond(r, "does not exist"); respond(r, nil); } static void fsread(Req *r) { dirread9p(r, dirgen, r->fid); respond(r, nil); } static void fsopen(Req *r) { r->ofcall.mode = r->ifcall.mode; if(r->ifcall.mode != OREAD) respond(r, "permission denied"); else respond(r, nil); } Srv fs= { .attach= fsattach, .open= fsopen, .read= fsread, .stat= fsstat, .walk= fswalk, .destroyfid= fidclunk }; void usage(void) { fprint(2, "usage: %s [ -Di ] [ -s service ] [ -t mode ] [ mntpt ]\n", argv0); exits("usage"); } void main(int argc, char **argv) { char *s, *mode; char *mtpt; int stdio; s = nil; stdio = 0; defmode = 'f'; ARGBEGIN{ case 'D': chatty9p++; break; case 's': s = EARGF(usage()); break; case 'i': stdio = 1; break; case 't': mode = EARGF(usage()); defmode = mode[0]; break; default: usage(); }ARGEND if(argc > 1) usage(); if(stdio == 0){ if(s != nil && argc == 0) mtpt = nil; else if(argc) mtpt = argv[0]; else mtpt = "/mnt/skel"; postmountsrv(&fs, s, mtpt, MREPL); exits(nil); } fs.infd = 0; fs.outfd = 1; srv(&fs); exits(nil); }