service_manager.c revision 6c929510474caa14dc9d56826b2c65552861d6b3 
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_RADIO, "radio.phone" },
37    { AID_RADIO, "radio.sms" },
38    { AID_RADIO, "radio.phonesubinfo" },
39    { AID_RADIO, "radio.simphonebook" },
40/* TODO: remove after phone services are updated: */
41    { AID_RADIO, "phone" },
42    { AID_RADIO, "sip" },
43    { AID_RADIO, "isms" },
44    { AID_RADIO, "iphonesubinfo" },
45    { AID_RADIO, "simphonebook" },
46    { AID_MEDIA, "common_time.clock" },
47    { AID_MEDIA, "common_time.config" },
48};
49
50void *svcmgr_handle;
51
52const char *str8(uint16_t *x)
53{
54    static char buf[128];
55    unsigned max = 127;
56    char *p = buf;
57
58    if (x) {
59        while (*x && max--) {
60            *p++ = *x++;
61        }
62    }
63    *p++ = 0;
64    return buf;
65}
66
67int str16eq(uint16_t *a, const char *b)
68{
69    while (*a && *b)
70        if (*a++ != *b++) return 0;
71    if (*a || *b)
72        return 0;
73    return 1;
74}
75
76int svc_can_register(unsigned uid, uint16_t *name)
77{
78    unsigned n;
79
80    if ((uid == 0) || (uid == AID_SYSTEM))
81        return 1;
82
83    for (n = 0; n < sizeof(allowed) / sizeof(allowed[0]); n++)
84        if ((uid == allowed[n].uid) && str16eq(name, allowed[n].name))
85            return 1;
86
87    return 0;
88}
89
90struct svcinfo
91{
92    struct svcinfo *next;
93    void *ptr;
94    struct binder_death death;
95    int allow_isolated;
96    unsigned len;
97    uint16_t name[0];
98};
99
100struct svcinfo *svclist = 0;
101
102struct svcinfo *find_svc(uint16_t *s16, unsigned len)
103{
104    struct svcinfo *si;
105
106    for (si = svclist; si; si = si->next) {
107        if ((len == si->len) &&
108            !memcmp(s16, si->name, len * sizeof(uint16_t))) {
109            return si;
110        }
111    }
112    return 0;
113}
114
115void svcinfo_death(struct binder_state *bs, void *ptr)
116{
117    struct svcinfo *si = ptr;
118    ALOGI("service '%s' died\n", str8(si->name));
119    if (si->ptr) {
120        binder_release(bs, si->ptr);
121        si->ptr = 0;
122    }
123}
124
125uint16_t svcmgr_id[] = {
126    'a','n','d','r','o','i','d','.','o','s','.',
127    'I','S','e','r','v','i','c','e','M','a','n','a','g','e','r'
128};
129
130
131void *do_find_service(struct binder_state *bs, uint16_t *s, unsigned len, unsigned uid)
132{
133    struct svcinfo *si;
134    si = find_svc(s, len);
135
136//    ALOGI("check_service('%s') ptr = %p\n", str8(s), si ? si->ptr : 0);
137    if (si && si->ptr) {
138        if (!si->allow_isolated) {
139            // If this service doesn't allow access from isolated processes,
140            // then check the uid to see if it is isolated.
141            unsigned appid = uid % AID_USER;
142            if (appid >= AID_ISOLATED_START && appid <= AID_ISOLATED_END) {
143                return 0;
144            }
145        }
146        return si->ptr;
147    } else {
148        return 0;
149    }
150}
151
152int do_add_service(struct binder_state *bs,
153                   uint16_t *s, unsigned len,
154                   void *ptr, unsigned uid, int allow_isolated)
155{
156    struct svcinfo *si;
157    //ALOGI("add_service('%s',%p,%s) uid=%d\n", str8(s), ptr,
158    //        allow_isolated ? "allow_isolated" : "!allow_isolated", uid);
159
160    if (!ptr || (len == 0) || (len > 127))
161        return -1;
162
163    if (!svc_can_register(uid, s)) {
164        ALOGE("add_service('%s',%p) uid=%d - PERMISSION DENIED\n",
165             str8(s), ptr, uid);
166        return -1;
167    }
168
169    si = find_svc(s, len);
170    if (si) {
171        if (si->ptr) {
172            ALOGE("add_service('%s',%p) uid=%d - ALREADY REGISTERED, OVERRIDE\n",
173                 str8(s), ptr, uid);
174            svcinfo_death(bs, si);
175        }
176        si->ptr = ptr;
177    } else {
178        si = malloc(sizeof(*si) + (len + 1) * sizeof(uint16_t));
179        if (!si) {
180            ALOGE("add_service('%s',%p) uid=%d - OUT OF MEMORY\n",
181                 str8(s), ptr, uid);
182            return -1;
183        }
184        si->ptr = ptr;
185        si->len = len;
186        memcpy(si->name, s, (len + 1) * sizeof(uint16_t));
187        si->name[len] = '\0';
188        si->death.func = svcinfo_death;
189        si->death.ptr = si;
190        si->allow_isolated = allow_isolated;
191        si->next = svclist;
192        svclist = si;
193    }
194
195    binder_acquire(bs, ptr);
196    binder_link_to_death(bs, ptr, &si->death);
197    return 0;
198}
199
200int svcmgr_handler(struct binder_state *bs,
201                   struct binder_txn *txn,
202                   struct binder_io *msg,
203                   struct binder_io *reply)
204{
205    struct svcinfo *si;
206    uint16_t *s;
207    unsigned len;
208    void *ptr;
209    uint32_t strict_policy;
210    int allow_isolated;
211
212//    ALOGI("target=%p code=%d pid=%d uid=%d\n",
213//         txn->target, txn->code, txn->sender_pid, txn->sender_euid);
214
215    if (txn->target != svcmgr_handle)
216        return -1;
217
218    // Equivalent to Parcel::enforceInterface(), reading the RPC
219    // header with the strict mode policy mask and the interface name.
220    // Note that we ignore the strict_policy and don't propagate it
221    // further (since we do no outbound RPCs anyway).
222    strict_policy = bio_get_uint32(msg);
223    s = bio_get_string16(msg, &len);
224    if ((len != (sizeof(svcmgr_id) / 2)) ||
225        memcmp(svcmgr_id, s, sizeof(svcmgr_id))) {
226        fprintf(stderr,"invalid id %s\n", str8(s));
227        return -1;
228    }
229
230    switch(txn->code) {
231    case SVC_MGR_GET_SERVICE:
232    case SVC_MGR_CHECK_SERVICE:
233        s = bio_get_string16(msg, &len);
234        ptr = do_find_service(bs, s, len, txn->sender_euid);
235        if (!ptr)
236            break;
237        bio_put_ref(reply, ptr);
238        return 0;
239
240    case SVC_MGR_ADD_SERVICE:
241        s = bio_get_string16(msg, &len);
242        ptr = bio_get_ref(msg);
243        allow_isolated = bio_get_uint32(msg) ? 1 : 0;
244        if (do_add_service(bs, s, len, ptr, txn->sender_euid, allow_isolated))
245            return -1;
246        break;
247
248    case SVC_MGR_LIST_SERVICES: {
249        unsigned n = bio_get_uint32(msg);
250
251        si = svclist;
252        while ((n-- > 0) && si)
253            si = si->next;
254        if (si) {
255            bio_put_string16(reply, si->name);
256            return 0;
257        }
258        return -1;
259    }
260    default:
261        ALOGE("unknown code %d\n", txn->code);
262        return -1;
263    }
264
265    bio_put_uint32(reply, 0);
266    return 0;
267}
268
269int main(int argc, char **argv)
270{
271    struct binder_state *bs;
272    void *svcmgr = BINDER_SERVICE_MANAGER;
273
274    bs = binder_open(128*1024);
275
276    if (binder_become_context_manager(bs)) {
277        ALOGE("cannot become context manager (%s)\n", strerror(errno));
278        return -1;
279    }
280
281    svcmgr_handle = svcmgr;
282    binder_loop(bs, svcmgr_handler);
283    return 0;
284}
285