ref: cb5057c6b3f549328a09fb08b300a0f74f671520
dir: /os/port/devcap.c/
#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "error.h" #include "mp.h" #include "libsec.h" /* * Copyright © 2003 Vita Nuova Holdings Limited. All rights reserved. */ enum { Captimeout = 15, /* seconds until expiry */ Capidletime = 60 /* idle seconds before capwatch exits */ }; typedef struct Caps Caps; struct Caps { uchar hash[SHA1dlen]; ulong time; Caps* next; }; struct { QLock l; Caps* caps; int kpstarted; } allcaps; enum { Qdir, Qhash, Quse }; static Dirtab capdir[] = { ".", {Qdir, 0, QTDIR}, 0, DMDIR|0555, "capuse", {Quse, 0}, 0, 0222, "caphash", {Qhash, 0}, 0, 0200, }; static int ncapdir = nelem(capdir); static void capwatch(void *a) { Caps *c, **l; int idletime; USED(a); idletime = 0; for(;;){ tsleep(&up->sleep, return0, nil, 30*1000); qlock(&allcaps.l); for(l = &allcaps.caps; (c = *l) != nil;) if(++c->time > Captimeout){ *l = c->next; free(c); }else l = &c->next; if(allcaps.caps == nil){ if(++idletime > Capidletime){ allcaps.kpstarted = 0; qunlock(&allcaps.l); pexit("", 0); } }else idletime = 0; qunlock(&allcaps.l); } } 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, nelem(capdir), devgen); } static int capstat(Chan *c, uchar *db, int n) { return devstat(c, db, n, capdir, nelem(capdir), devgen); } static Chan* capopen(Chan *c, int omode) { if(c->qid.type & QTDIR) { if(omode != OREAD) error(Eisdir); c->mode = omode; c->flag |= COPEN; c->offset = 0; return c; } if(c->qid.path == Qhash && !iseve()) error(Eperm); c->mode = openmode(omode); c->flag |= COPEN; c->offset = 0; return c; } static void capclose(Chan *c) { USED(c); } static long capread(Chan *c, void *va, long n, vlong vl) { USED(vl); switch((ulong)c->qid.path){ case Qdir: return devdirread(c, va, n, capdir, ncapdir, devgen); default: error(Eperm); break; } return n; } static int capwritehash(uchar *a, int l) { Caps *c; if(l != SHA1dlen) return -1; c = malloc(sizeof(*c)); if(c == nil) return -1; memmove(c->hash, a, l); c->time = 0; qlock(&allcaps.l); c->next = allcaps.caps; allcaps.caps = c; if(!allcaps.kpstarted){ allcaps.kpstarted = 1; kproc("capwatch", capwatch, 0, 0); } qunlock(&allcaps.l); return 0; } static int capwriteuse(uchar *a, int len) { int n; uchar digest[SHA1dlen]; char buf[128], *p, *users[3]; Caps *c, **l; if(len >= sizeof(buf)-1) return -1; memmove(buf, a, len); buf[len] = 0; p = strrchr(buf, '@'); if(p == nil) return -1; *p++ = 0; len = strlen(p); n = strlen(buf); if(len == 0 || n == 0) return -1; hmac_sha1((uchar*)buf, n, (uchar*)p, len, digest, nil); n = getfields(buf, users, nelem(users), 0, "@"); if(n == 1) users[1] = users[0]; else if(n != 2) return -1; if(*users[0] == 0 || *users[1] == 0) return -1; qlock(&allcaps.l); for(l = &allcaps.caps; (c = *l) != nil; l = &c->next) if(memcmp(c->hash, digest, sizeof(c->hash)) == 0){ *l = c->next; qunlock(&allcaps.l); free(c); if(n == 2 && strcmp(up->env->user, users[0]) != 0) return -1; kstrdup(&up->env->user, users[1]); return 0; } qunlock(&allcaps.l); return -1; } static long capwrite(Chan* c, void* buf, long n, vlong offset) { USED(offset); switch((ulong)c->qid.path){ case Qhash: if(capwritehash(buf, n) < 0) error(Ebadarg); return n; case Quse: if(capwriteuse(buf, n) < 0) error("invalid capability"); return n; } error(Ebadarg); return 0; } static void capremove(Chan *c) { if(c->qid.path != Qhash || !iseve()) error(Eperm); ncapdir = nelem(capdir)-1; } Dev capdevtab = { L'¤', "cap", devreset, devinit, devshutdown, capattach, capwalk, capstat, capopen, devcreate, capclose, capread, devbread, capwrite, devbwrite, capremove, devwstat };