service_manager.c revision 244408786cf1f374eeacbf6d16dd5a6f7b5e3c59 
1/* Copyright 2008 The Android Open Source Project
2 */
3
4#include <stdio.h>
5#include <stdlib.h>
6#include <errno.h>
7#include <fcntl.h>
8
9#include <private/android_filesystem_config.h>
10
11#include "binder.h"
12
13#if 0
14#define ALOGI(x...) fprintf(stderr, "svcmgr: " x)
15#define ALOGE(x...) fprintf(stderr, "svcmgr: " x)
16#else
17#define LOG_TAG "ServiceManager"
18#include <cutils/log.h>
19#endif
20
21/* TODO:
22 * These should come from a config file or perhaps be
23 * based on some namespace rules of some sort (media
24 * uid can register media.*, etc)
25 */
26static struct {
27    unsigned uid;
28    const char *name;
29} allowed[] = {
30    { AID_MEDIA, "media.audio_flinger" },
31    { AID_MEDIA, "media.player" },
32    { AID_MEDIA, "media.camera" },
33    { AID_MEDIA, "media.audio_policy" },
34    { AID_DRM,   "drm.drmManager" },
35    { AID_NFC,   "nfc" },
36    { AID_BLUETOOTH, "bluetooth" },
37    { AID_RADIO, "radio.phone" },
38    { AID_RADIO, "radio.sms" },
39    { AID_RADIO, "radio.phonesubinfo" },
40    { AID_RADIO, "radio.simphonebook" },
41/* TODO: remove after phone services are updated: */
42    { AID_RADIO, "phone" },
43    { AID_RADIO, "sip" },
44    { AID_RADIO, "isms" },
45    { AID_RADIO, "iphonesubinfo" },
46    { AID_RADIO, "simphonebook" },
47    { AID_MEDIA, "common_time.clock" },
48    { AID_MEDIA, "common_time.config" },
49    { AID_KEYSTORE, "android.security.keystore" },
50};
51
52void *svcmgr_handle;
53
54const char *str8(uint16_t *x)
55{
56    static char buf[128];
57    unsigned max = 127;
58    char *p = buf;
59
60    if (x) {
61        while (*x && max--) {
62            *p++ = *x++;
63        }
64    }
65    *p++ = 0;
66    return buf;
67}
68
69int str16eq(uint16_t *a, const char *b)
70{
71    while (*a && *b)
72        if (*a++ != *b++) return 0;
73    if (*a || *b)
74        return 0;
75    return 1;
76}
77
78int svc_can_register(unsigned uid, uint16_t *name)
79{
80    unsigned n;
81
82    if ((uid == 0) || (uid == AID_SYSTEM))
83        return 1;
84
85    for (n = 0; n < sizeof(allowed) / sizeof(allowed[0]); n++)
86        if ((uid == allowed[n].uid) && str16eq(name, allowed[n].name))
87            return 1;
88
89    return 0;
90}
91
92struct svcinfo
93{
94    struct svcinfo *next;
95    void *ptr;
96    struct binder_death death;
97    int allow_isolated;
98    unsigned len;
99    uint16_t name[0];
100};
101
102struct svcinfo *svclist = 0;
103
104struct svcinfo *find_svc(uint16_t *s16, unsigned len)
105{
106    struct svcinfo *si;
107
108    for (si = svclist; si; si = si->next) {
109        if ((len == si->len) &&
110            !memcmp(s16, si->name, len * sizeof(uint16_t))) {
111            return si;
112        }
113    }
114    return 0;
115}
116
117void svcinfo_death(struct binder_state *bs, void *ptr)
118{
119    struct svcinfo *si = ptr;
120    ALOGI("service '%s' died\n", str8(si->name));
121    if (si->ptr) {
122        binder_release(bs, si->ptr);
123        si->ptr = 0;
124    }
125}
126
127uint16_t svcmgr_id[] = {
128    'a','n','d','r','o','i','d','.','o','s','.',
129    'I','S','e','r','v','i','c','e','M','a','n','a','g','e','r'
130};
131
132
133void *do_find_service(struct binder_state *bs, uint16_t *s, unsigned len, unsigned uid)
134{
135    struct svcinfo *si;
136    si = find_svc(s, len);
137
138//    ALOGI("check_service('%s') ptr = %p\n", str8(s), si ? si->ptr : 0);
139    if (si && si->ptr) {
140        if (!si->allow_isolated) {
141            // If this service doesn't allow access from isolated processes,
142            // then check the uid to see if it is isolated.
143            unsigned appid = uid % AID_USER;
144            if (appid >= AID_ISOLATED_START && appid <= AID_ISOLATED_END) {
145                return 0;
146            }
147        }
148        return si->ptr;
149    } else {
150        return 0;
151    }
152}
153
154int do_add_service(struct binder_state *bs,
155                   uint16_t *s, unsigned len,
156                   void *ptr, unsigned uid, int allow_isolated)
157{
158    struct svcinfo *si;
159    //ALOGI("add_service('%s',%p,%s) uid=%d\n", str8(s), ptr,
160    //        allow_isolated ? "allow_isolated" : "!allow_isolated", uid);
161
162    if (!ptr || (len == 0) || (len > 127))
163        return -1;
164
165    if (!svc_can_register(uid, s)) {
166        ALOGE("add_service('%s',%p) uid=%d - PERMISSION DENIED\n",
167             str8(s), ptr, uid);
168        return -1;
169    }
170
171    si = find_svc(s, len);
172    if (si) {
173        if (si->ptr) {
174            ALOGE("add_service('%s',%p) uid=%d - ALREADY REGISTERED, OVERRIDE\n",
175                 str8(s), ptr, uid);
176            svcinfo_death(bs, si);
177        }
178        si->ptr = ptr;
179    } else {
180        si = malloc(sizeof(*si) + (len + 1) * sizeof(uint16_t));
181        if (!si) {
182            ALOGE("add_service('%s',%p) uid=%d - OUT OF MEMORY\n",
183                 str8(s), ptr, uid);
184            return -1;
185        }
186        si->ptr = ptr;
187        si->len = len;
188        memcpy(si->name, s, (len + 1) * sizeof(uint16_t));
189        si->name[len] = '\0';
190        si->death.func = svcinfo_death;
191        si->death.ptr = si;
192        si->allow_isolated = allow_isolated;
193        si->next = svclist;
194        svclist = si;
195    }
196
197    binder_acquire(bs, ptr);
198    binder_link_to_death(bs, ptr, &si->death);
199    return 0;
200}
201
202int svcmgr_handler(struct binder_state *bs,
203                   struct binder_txn *txn,
204                   struct binder_io *msg,
205                   struct binder_io *reply)
206{
207    struct svcinfo *si;
208    uint16_t *s;
209    unsigned len;
210    void *ptr;
211    uint32_t strict_policy;
212    int allow_isolated;
213
214//    ALOGI("target=%p code=%d pid=%d uid=%d\n",
215//         txn->target, txn->code, txn->sender_pid, txn->sender_euid);
216
217    if (txn->target != svcmgr_handle)
218        return -1;
219
220    // Equivalent to Parcel::enforceInterface(), reading the RPC
221    // header with the strict mode policy mask and the interface name.
222    // Note that we ignore the strict_policy and don't propagate it
223    // further (since we do no outbound RPCs anyway).
224    strict_policy = bio_get_uint32(msg);
225    s = bio_get_string16(msg, &len);
226    if ((len != (sizeof(svcmgr_id) / 2)) ||
227        memcmp(svcmgr_id, s, sizeof(svcmgr_id))) {
228        fprintf(stderr,"invalid id %s\n", str8(s));
229        return -1;
230    }
231
232    switch(txn->code) {
233    case SVC_MGR_GET_SERVICE:
234    case SVC_MGR_CHECK_SERVICE:
235        s = bio_get_string16(msg, &len);
236        ptr = do_find_service(bs, s, len, txn->sender_euid);
237        if (!ptr)
238            break;
239        bio_put_ref(reply, ptr);
240        return 0;
241
242    case SVC_MGR_ADD_SERVICE:
243        s = bio_get_string16(msg, &len);
244        ptr = bio_get_ref(msg);
245        allow_isolated = bio_get_uint32(msg) ? 1 : 0;
246        if (do_add_service(bs, s, len, ptr, txn->sender_euid, allow_isolated))
247            return -1;
248        break;
249
250    case SVC_MGR_LIST_SERVICES: {
251        unsigned n = bio_get_uint32(msg);
252
253        si = svclist;
254        while ((n-- > 0) && si)
255            si = si->next;
256        if (si) {
257            bio_put_string16(reply, si->name);
258            return 0;
259        }
260        return -1;
261    }
262    default:
263        ALOGE("unknown code %d\n", txn->code);
264        return -1;
265    }
266
267    bio_put_uint32(reply, 0);
268    return 0;
269}
270
271int main(int argc, char **argv)
272{
273    struct binder_state *bs;
274    void *svcmgr = BINDER_SERVICE_MANAGER;
275
276    bs = binder_open(128*1024);
277
278    if (binder_become_context_manager(bs)) {
279        ALOGE("cannot become context manager (%s)\n", strerror(errno));
280        return -1;
281    }
282
283    svcmgr_handle = svcmgr;
284    binder_loop(bs, svcmgr_handler);
285    return 0;
286}
287