service_manager.c revision a44542ca74b7da5b44ba30c205c3244805bb0600 
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.log" },
32    { AID_MEDIA, "media.player" },
33    { AID_MEDIA, "media.camera" },
34    { AID_MEDIA, "media.audio_policy" },
35    { AID_DRM,   "drm.drmManager" },
36    { AID_NFC,   "nfc" },
37    { AID_BLUETOOTH, "bluetooth" },
38    { AID_RADIO, "radio.phone" },
39    { AID_RADIO, "radio.sms" },
40    { AID_RADIO, "radio.phonesubinfo" },
41    { AID_RADIO, "radio.simphonebook" },
42/* TODO: remove after phone services are updated: */
43    { AID_RADIO, "phone" },
44    { AID_RADIO, "sip" },
45    { AID_RADIO, "isms" },
46    { AID_RADIO, "iphonesubinfo" },
47    { AID_RADIO, "simphonebook" },
48    { AID_MEDIA, "common_time.clock" },
49    { AID_MEDIA, "common_time.config" },
50    { AID_KEYSTORE, "android.security.keystore" },
51};
52
53void *svcmgr_handle;
54
55const char *str8(uint16_t *x)
56{
57    static char buf[128];
58    unsigned max = 127;
59    char *p = buf;
60
61    if (x) {
62        while (*x && max--) {
63            *p++ = *x++;
64        }
65    }
66    *p++ = 0;
67    return buf;
68}
69
70int str16eq(uint16_t *a, const char *b)
71{
72    while (*a && *b)
73        if (*a++ != *b++) return 0;
74    if (*a || *b)
75        return 0;
76    return 1;
77}
78
79int svc_can_register(unsigned uid, uint16_t *name)
80{
81    unsigned n;
82
83    if ((uid == 0) || (uid == AID_SYSTEM))
84        return 1;
85
86    for (n = 0; n < sizeof(allowed) / sizeof(allowed[0]); n++)
87        if ((uid == allowed[n].uid) && str16eq(name, allowed[n].name))
88            return 1;
89
90    return 0;
91}
92
93struct svcinfo
94{
95    struct svcinfo *next;
96    void *ptr;
97    struct binder_death death;
98    int allow_isolated;
99    unsigned len;
100    uint16_t name[0];
101};
102
103struct svcinfo *svclist = 0;
104
105struct svcinfo *find_svc(uint16_t *s16, unsigned len)
106{
107    struct svcinfo *si;
108
109    for (si = svclist; si; si = si->next) {
110        if ((len == si->len) &&
111            !memcmp(s16, si->name, len * sizeof(uint16_t))) {
112            return si;
113        }
114    }
115    return 0;
116}
117
118void svcinfo_death(struct binder_state *bs, void *ptr)
119{
120    struct svcinfo *si = ptr;
121    ALOGI("service '%s' died\n", str8(si->name));
122    if (si->ptr) {
123        binder_release(bs, si->ptr);
124        si->ptr = 0;
125    }
126}
127
128uint16_t svcmgr_id[] = {
129    'a','n','d','r','o','i','d','.','o','s','.',
130    'I','S','e','r','v','i','c','e','M','a','n','a','g','e','r'
131};
132
133
134void *do_find_service(struct binder_state *bs, uint16_t *s, unsigned len, unsigned uid)
135{
136    struct svcinfo *si;
137    si = find_svc(s, len);
138
139//    ALOGI("check_service('%s') ptr = %p\n", str8(s), si ? si->ptr : 0);
140    if (si && si->ptr) {
141        if (!si->allow_isolated) {
142            // If this service doesn't allow access from isolated processes,
143            // then check the uid to see if it is isolated.
144            unsigned appid = uid % AID_USER;
145            if (appid >= AID_ISOLATED_START && appid <= AID_ISOLATED_END) {
146                return 0;
147            }
148        }
149        return si->ptr;
150    } else {
151        return 0;
152    }
153}
154
155int do_add_service(struct binder_state *bs,
156                   uint16_t *s, unsigned len,
157                   void *ptr, unsigned uid, int allow_isolated)
158{
159    struct svcinfo *si;
160    //ALOGI("add_service('%s',%p,%s) uid=%d\n", str8(s), ptr,
161    //        allow_isolated ? "allow_isolated" : "!allow_isolated", uid);
162
163    if (!ptr || (len == 0) || (len > 127))
164        return -1;
165
166    if (!svc_can_register(uid, s)) {
167        ALOGE("add_service('%s',%p) uid=%d - PERMISSION DENIED\n",
168             str8(s), ptr, uid);
169        return -1;
170    }
171
172    si = find_svc(s, len);
173    if (si) {
174        if (si->ptr) {
175            ALOGE("add_service('%s',%p) uid=%d - ALREADY REGISTERED, OVERRIDE\n",
176                 str8(s), ptr, uid);
177            svcinfo_death(bs, si);
178        }
179        si->ptr = ptr;
180    } else {
181        si = malloc(sizeof(*si) + (len + 1) * sizeof(uint16_t));
182        if (!si) {
183            ALOGE("add_service('%s',%p) uid=%d - OUT OF MEMORY\n",
184                 str8(s), ptr, uid);
185            return -1;
186        }
187        si->ptr = ptr;
188        si->len = len;
189        memcpy(si->name, s, (len + 1) * sizeof(uint16_t));
190        si->name[len] = '\0';
191        si->death.func = svcinfo_death;
192        si->death.ptr = si;
193        si->allow_isolated = allow_isolated;
194        si->next = svclist;
195        svclist = si;
196    }
197
198    binder_acquire(bs, ptr);
199    binder_link_to_death(bs, ptr, &si->death);
200    return 0;
201}
202
203int svcmgr_handler(struct binder_state *bs,
204                   struct binder_transaction_data *txn,
205                   struct binder_io *msg,
206                   struct binder_io *reply)
207{
208    struct svcinfo *si;
209    uint16_t *s;
210    unsigned len;
211    void *ptr;
212    uint32_t strict_policy;
213    int allow_isolated;
214
215//    ALOGI("target=%p code=%d pid=%d uid=%d\n",
216//         txn->target, txn->code, txn->sender_pid, txn->sender_euid);
217
218    if (txn->target.handle != svcmgr_handle)
219        return -1;
220
221    // Equivalent to Parcel::enforceInterface(), reading the RPC
222    // header with the strict mode policy mask and the interface name.
223    // Note that we ignore the strict_policy and don't propagate it
224    // further (since we do no outbound RPCs anyway).
225    strict_policy = bio_get_uint32(msg);
226    s = bio_get_string16(msg, &len);
227    if ((len != (sizeof(svcmgr_id) / 2)) ||
228        memcmp(svcmgr_id, s, sizeof(svcmgr_id))) {
229        fprintf(stderr,"invalid id %s\n", str8(s));
230        return -1;
231    }
232
233    switch(txn->code) {
234    case SVC_MGR_GET_SERVICE:
235    case SVC_MGR_CHECK_SERVICE:
236        s = bio_get_string16(msg, &len);
237        ptr = do_find_service(bs, s, len, txn->sender_euid);
238        if (!ptr)
239            break;
240        bio_put_ref(reply, ptr);
241        return 0;
242
243    case SVC_MGR_ADD_SERVICE:
244        s = bio_get_string16(msg, &len);
245        ptr = bio_get_ref(msg);
246        allow_isolated = bio_get_uint32(msg) ? 1 : 0;
247        if (do_add_service(bs, s, len, ptr, txn->sender_euid, allow_isolated))
248            return -1;
249        break;
250
251    case SVC_MGR_LIST_SERVICES: {
252        unsigned n = bio_get_uint32(msg);
253
254        si = svclist;
255        while ((n-- > 0) && si)
256            si = si->next;
257        if (si) {
258            bio_put_string16(reply, si->name);
259            return 0;
260        }
261        return -1;
262    }
263    default:
264        ALOGE("unknown code %d\n", txn->code);
265        return -1;
266    }
267
268    bio_put_uint32(reply, 0);
269    return 0;
270}
271
272int main(int argc, char **argv)
273{
274    struct binder_state *bs;
275    void *svcmgr = BINDER_SERVICE_MANAGER;
276
277    bs = binder_open(128*1024);
278    if (!bs) {
279        ALOGE("failed to open binder driver\n");
280        return -1;
281    }
282
283    if (binder_become_context_manager(bs)) {
284        ALOGE("cannot become context manager (%s)\n", strerror(errno));
285        return -1;
286    }
287
288    svcmgr_handle = svcmgr;
289    binder_loop(bs, svcmgr_handler);
290    return 0;
291}
292