1996/0116/port/devtinyfs.c (diff list | history)

port/devtinyfs.c on 1996/0116
1996/0116		/* * template for making a new device */ #include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" #include "devtab.h" enum{ Qdir, Qmedium, Nfile= 32, }; struct { QLock; Chan *c; Dirtab file[Nfile]; int nfile; } tinyfs; void tinyfsreset(void) { Dirtab *d; d = tinyfs.file; memmove(d->name, "medium"); d->qid.vers = 0; d->qid.path = Qdata; d->perm = 0666; } void tinyfsinit(void) { } Chan * tinyfsattach(char *spec) { return devattach('E', spec); } Chan * tinyfsclone(Chan *c, Chan *nc) { return devclone(c, nc); } int tinyfswalk(Chan *c, char *name) { return devwalk(c, name, tinyfs.file, tinyfs.nfile, devgen); } void tinyfsstat(Chan *c, char *db) { devstat(c, db, tinyfs.file, tinyfs.nfile, devgen); } Chan * tinyfsopen(Chan *c, int omode) { return devopen(c, omode, tinyfs.file, tinyfs.nfile, devgen); } void tinyfscreate(Chan *c, char *name, int omode, ulong perm) { Dirtab *d; if(perm & CHDIR) error("directory creation illegal"); if(waserror()){ qunlock(&tinyfs); nexterror(); } qlock(&tinyfs); if(tinyfs.nfile == Nfile) error("out of space"); for(d = tinyfs.file; d < tinyfs.file[tinyfs.nfile]; d++) if(strcmp(name, d->name) == 0) error("create race"); strncpy(d->name, name, sizeof(d->name)-1); d->perm = perm; d->qid.vers = 0; d->qid.path = tinyfs.high++; tinyfs.nfile++; qunlock(&tinyfs); c->mode = openmode(omode); c->flag |= COPEN; c->qid = d->qid; } void tinyfsremove(Chan *c) { USED(c); error(Eperm); } void tinyfswstat(Chan *c, char *dp) { USED(c, dp); error(Eperm); } void tinyfsclose(Chan *c) { } long tinyfsread(Chan *c, void *a, long n, ulong offset) { switch(c->qid.path & ~CHDIR){ case Qdir: return devdirread(c, a, n, tinyfstab, Ntinyfstab, devgen); case Qdata: break; default: n=0; break; } return n; } Block* tinyfsbread(Chan *c, long n, ulong offset) { return devbread(c, n, offset); } long tinyfswrite(Chan *c, char *a, long n, ulong offset) { if(waserror()){ qunlock(&tinyfs); nexterror(); } qlock(&tinyfs); qunlock(&tinyfs); switch(c->qid.path & ~CHDIR){ case Qdata: break; default: error(Ebadusefd); } return n; } long tinyfsbwrite(Chan *c, Block *bp, ulong offset) { return devbwrite(c, bp, offset); }