service_manager.c revision 94afecf4b6f437b3ee9a076242402e421c6c07a6 
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};
50
51void *svcmgr_handle;
52
53const char *str8(uint16_t *x)
54{
55    static char buf[128];
56    unsigned max = 127;
57    char *p = buf;
58
59    if (x) {
60        while (*x && max--) {
61            *p++ = *x++;
62        }
63    }
64    *p++ = 0;
65    return buf;
66}
67
68int str16eq(uint16_t *a, const char *b)
69{
70    while (*a && *b)
71        if (*a++ != *b++) return 0;
72    if (*a || *b)
73        return 0;
74    return 1;
75}
76
77int svc_can_register(unsigned uid, uint16_t *name)
78{
79    unsigned n;
80
81    if ((uid == 0) || (uid == AID_SYSTEM))
82        return 1;
83
84    for (n = 0; n < sizeof(allowed) / sizeof(allowed[0]); n++)
85        if ((uid == allowed[n].uid) && str16eq(name, allowed[n].name))
86            return 1;
87
88    return 0;
89}
90
91struct svcinfo
92{
93    struct svcinfo *next;
94    void *ptr;
95    struct binder_death death;
96    int allow_isolated;
97    unsigned len;
98    uint16_t name[0];
99};
100
101struct svcinfo *svclist = 0;
102
103struct svcinfo *find_svc(uint16_t *s16, unsigned len)
104{
105    struct svcinfo *si;
106
107    for (si = svclist; si; si = si->next) {
108        if ((len == si->len) &&
109            !memcmp(s16, si->name, len * sizeof(uint16_t))) {
110            return si;
111        }
112    }
113    return 0;
114}
115
116void svcinfo_death(struct binder_state *bs, void *ptr)
117{
118    struct svcinfo *si = ptr;
119    ALOGI("service '%s' died\n", str8(si->name));
120    if (si->ptr) {
121        binder_release(bs, si->ptr);
122        si->ptr = 0;
123    }
124}
125
126uint16_t svcmgr_id[] = {
127    'a','n','d','r','o','i','d','.','o','s','.',
128    'I','S','e','r','v','i','c','e','M','a','n','a','g','e','r'
129};
130
131
132void *do_find_service(struct binder_state *bs, uint16_t *s, unsigned len, unsigned uid)
133{
134    struct svcinfo *si;
135    si = find_svc(s, len);
136
137//    ALOGI("check_service('%s') ptr = %p\n", str8(s), si ? si->ptr : 0);
138    if (si && si->ptr) {
139        if (!si->allow_isolated) {
140            // If this service doesn't allow access from isolated processes,
141            // then check the uid to see if it is isolated.
142            unsigned appid = uid % AID_USER;
143            if (appid >= AID_ISOLATED_START && appid <= AID_ISOLATED_END) {
144                return 0;
145            }
146        }
147        return si->ptr;
148    } else {
149        return 0;
150    }
151}
152
153int do_add_service(struct binder_state *bs,
154                   uint16_t *s, unsigned len,
155                   void *ptr, unsigned uid, int allow_isolated)
156{
157    struct svcinfo *si;
158    //ALOGI("add_service('%s',%p,%s) uid=%d\n", str8(s), ptr,
159    //        allow_isolated ? "allow_isolated" : "!allow_isolated", uid);
160
161    if (!ptr || (len == 0) || (len > 127))
162        return -1;
163
164    if (!svc_can_register(uid, s)) {
165        ALOGE("add_service('%s',%p) uid=%d - PERMISSION DENIED\n",
166             str8(s), ptr, uid);
167        return -1;
168    }
169
170    si = find_svc(s, len);
171    if (si) {
172        if (si->ptr) {
173            ALOGE("add_service('%s',%p) uid=%d - ALREADY REGISTERED, OVERRIDE\n",
174                 str8(s), ptr, uid);
175            svcinfo_death(bs, si);
176        }
177        si->ptr = ptr;
178    } else {
179        si = malloc(sizeof(*si) + (len + 1) * sizeof(uint16_t));
180        if (!si) {
181            ALOGE("add_service('%s',%p) uid=%d - OUT OF MEMORY\n",
182                 str8(s), ptr, uid);
183            return -1;
184        }
185        si->ptr = ptr;
186        si->len = len;
187        memcpy(si->name, s, (len + 1) * sizeof(uint16_t));
188        si->name[len] = '\0';
189        si->death.func = svcinfo_death;
190        si->death.ptr = si;
191        si->allow_isolated = allow_isolated;
192        si->next = svclist;
193        svclist = si;
194    }
195
196    binder_acquire(bs, ptr);
197    binder_link_to_death(bs, ptr, &si->death);
198    return 0;
199}
200
201int svcmgr_handler(struct binder_state *bs,
202                   struct binder_txn *txn,
203                   struct binder_io *msg,
204                   struct binder_io *reply)
205{
206    struct svcinfo *si;
207    uint16_t *s;
208    unsigned len;
209    void *ptr;
210    uint32_t strict_policy;
211    int allow_isolated;
212
213//    ALOGI("target=%p code=%d pid=%d uid=%d\n",
214//         txn->target, txn->code, txn->sender_pid, txn->sender_euid);
215
216    if (txn->target != svcmgr_handle)
217        return -1;
218
219    // Equivalent to Parcel::enforceInterface(), reading the RPC
220    // header with the strict mode policy mask and the interface name.
221    // Note that we ignore the strict_policy and don't propagate it
222    // further (since we do no outbound RPCs anyway).
223    strict_policy = bio_get_uint32(msg);
224    s = bio_get_string16(msg, &len);
225    if ((len != (sizeof(svcmgr_id) / 2)) ||
226        memcmp(svcmgr_id, s, sizeof(svcmgr_id))) {
227        fprintf(stderr,"invalid id %s\n", str8(s));
228        return -1;
229    }
230
231    switch(txn->code) {
232    case SVC_MGR_GET_SERVICE:
233    case SVC_MGR_CHECK_SERVICE:
234        s = bio_get_string16(msg, &len);
235        ptr = do_find_service(bs, s, len, txn->sender_euid);
236        if (!ptr)
237            break;
238        bio_put_ref(reply, ptr);
239        return 0;
240
241    case SVC_MGR_ADD_SERVICE:
242        s = bio_get_string16(msg, &len);
243        ptr = bio_get_ref(msg);
244        allow_isolated = bio_get_uint32(msg) ? 1 : 0;
245        if (do_add_service(bs, s, len, ptr, txn->sender_euid, allow_isolated))
246            return -1;
247        break;
248
249    case SVC_MGR_LIST_SERVICES: {
250        unsigned n = bio_get_uint32(msg);
251
252        si = svclist;
253        while ((n-- > 0) && si)
254            si = si->next;
255        if (si) {
256            bio_put_string16(reply, si->name);
257            return 0;
258        }
259        return -1;
260    }
261    default:
262        ALOGE("unknown code %d\n", txn->code);
263        return -1;
264    }
265
266    bio_put_uint32(reply, 0);
267    return 0;
268}
269
270int main(int argc, char **argv)
271{
272    struct binder_state *bs;
273    void *svcmgr = BINDER_SERVICE_MANAGER;
274
275    bs = binder_open(128*1024);
276
277    if (binder_become_context_manager(bs)) {
278        ALOGE("cannot become context manager (%s)\n", strerror(errno));
279        return -1;
280    }
281
282    svcmgr_handle = svcmgr;
283    binder_loop(bs, svcmgr_handler);
284    return 0;
285}
286