2002/0202/port/devcap.c (diff list | history)

2002/0202/sys/src/9/port/devcap.c:1,277 – 2002/0622/sys/src/9/port/devcap.c:1,279 (short | long | prev | next)
2001/0527		#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" #include "netif.h" #include <libsec.h> enum { Hashlen= SHA1dlen, Maxhash= 256, }; /* * if a process knows cap->cap, it can change user * to capabilty->user. */ typedef struct Caphash Caphash; struct Caphash { Caphash *next; char hash[Hashlen]; ulong ticks; }; struct { QLock; int opens; Caphash *first; int nhash; } capalloc; enum { Qdir, Qhash, Quse, }; Dirtab capdir[] = { ".", {Qdir,0,QTDIR}, 0, DMDIR|0500, "caphash", {Qhash}, 0, 0200, "capuse", {Quse}, 0, 0222, }; #define NCAPDIR 3 static Chan* capattach(char *spec) { return devattach(L'¤', spec); } static Walkqid* capwalk(Chan *c, Chan *nc, char **name, int nname) { return devwalk(c, nc, name, nname, capdir, NCAPDIR, devgen); } static int capstat(Chan *c, uchar *db, int n) { return devstat(c, db, n, capdir, NCAPDIR, devgen); } /* * if the stream doesn't exist, create it */ static Chan* capopen(Chan *c, int omode) { if(c->qid.type & QTDIR){ if(omode != OREAD) error(Ebadarg); c->mode = omode; c->flag |= COPEN; c->offset = 0; return c; } if(waserror()){ qunlock(&capalloc); nexterror(); } qlock(&capalloc); switch((ulong)c->qid.path){ case Qhash:
2002/0622		if(!iseve()) error(Eperm);
2001/0527		if(capalloc.opens > 0){ qunlock(&capalloc); error("exclusive use"); } capalloc.opens++; break; } poperror(); qunlock(&capalloc); c->mode = openmode(omode); c->flag |= COPEN; c->offset = 0; return c; } static Caphash* remcap(uchar *hash) { Caphash *t, **l; qlock(&capalloc); /* find the matching capability */ for(l = &capalloc.first; *l != nil;){ t = *l; if(memcmp(hash, t->hash, Hashlen) == 0) break; l = &t->next; } t = *l; if(t != nil){ capalloc.nhash--; *l = t->next; } qunlock(&capalloc); return t; } /* add a capability, throwing out any old ones */ static void addcap(uchar *hash) { Caphash *p, *t, **l; p = smalloc(sizeof *p); memmove(p->hash, hash, Hashlen); p->next = nil; p->ticks = m->ticks; qlock(&capalloc); /* trim extras */ while(capalloc.nhash >= Maxhash){ t = capalloc.first; if(t == nil) panic("addcap"); capalloc.first = t->next; free(t); capalloc.nhash--; } /* add new one */ for(l = &capalloc.first; *l != nil; l = &(*l)->next) ; *l = p; capalloc.nhash++; qunlock(&capalloc); } static void capclose(Chan *c) { if(c->flag & COPEN) if(c->qid.path == Qhash){ qlock(&capalloc); capalloc.opens--; qunlock(&capalloc); } } static long capread(Chan *c, void *va, long n, vlong) { switch((ulong)c->qid.path){ case Qdir: return devdirread(c, va, n, capdir, nelem(capdir), devgen); default: error(Eperm); break; } return n; } static long capwrite(Chan *c, void *va, long n, vlong) { Caphash *p; char *cp; uchar hash[Hashlen];
2002/0202		char *key, *from, *to;
2001/0527		char err[256]; switch((ulong)c->qid.path){ case Qhash: if(n < Hashlen) error(Eshort); memmove(hash, va, Hashlen); addcap(hash); break; case Quse: /* copy key to avoid a fault in hmac_xx */ cp = nil; if(waserror()){ free(cp); nexterror(); } cp = smalloc(n+1); memmove(cp, va, n); cp[n] = 0;
2002/0202		from = cp; key = strrchr(cp, '@');
2001/0527		if(key == nil) error(Eshort); *key++ = 0;
2002/0202		hmac_sha1((uchar*)from, strlen(from), (uchar*)key, strlen(key), hash, nil);
2001/0527		p = remcap(hash); if(p == nil){
2002/0202		snprint(err, sizeof err, "invalid capability %s@%s", from, key);
2001/0527		error(err); }
2002/0202		/* if a from user is supplied, make sure it matches */ to = strchr(from, '@'); if(to == nil){ to = from; } else { *to++ = 0; if(strcmp(from, up->user) != 0) error("capability must match user"); }
2001/0527		/* set user id */
2002/0202		kstrdup(&up->user, to);
2001/0527		up->basepri = PriNormal; free(p); free(cp); poperror(); break; default: error(Eperm); break; } return n; } Dev capdevtab = { L'¤', "cap", devreset, devinit,
2002/0109		devshutdown,
2001/0527		capattach, capwalk, capstat, capopen, devcreate, capclose, capread, devbread, capwrite, devbwrite, devremove, devwstat, };