service_manager.c revision 9066cfe9886ac131c34d59ed0e2d287b0e3c0087 
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 LOGI(x...) fprintf(stderr, "svcmgr: " x)
15#define LOGE(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_RADIO, "radio.phone" },
34    { AID_RADIO, "radio.sms" },
35    { AID_RADIO, "radio.phonesubinfo" },
36    { AID_RADIO, "radio.simphonebook" },
37/* TODO: remove after phone services are updated: */
38    { AID_RADIO, "phone" },
39    { AID_RADIO, "isms" },
40    { AID_RADIO, "iphonesubinfo" },
41    { AID_RADIO, "simphonebook" },
42};
43
44void *svcmgr_handle;
45
46const char *str8(uint16_t *x)
47{
48    static char buf[128];
49    unsigned max = 127;
50    char *p = buf;
51
52    if (x) {
53        while (*x && max--) {
54            *p++ = *x++;
55        }
56    }
57    *p++ = 0;
58    return buf;
59}
60
61int str16eq(uint16_t *a, const char *b)
62{
63    while (*a && *b)
64        if (*a++ != *b++) return 0;
65    if (*a || *b)
66        return 0;
67    return 1;
68}
69
70int svc_can_register(unsigned uid, uint16_t *name)
71{
72    unsigned n;
73
74    if ((uid == 0) || (uid == AID_SYSTEM))
75        return 1;
76
77    for (n = 0; n < sizeof(allowed) / sizeof(allowed[0]); n++)
78        if ((uid == allowed[n].uid) && str16eq(name, allowed[n].name))
79            return 1;
80
81    return 0;
82}
83
84struct svcinfo
85{
86    struct svcinfo *next;
87    void *ptr;
88    struct binder_death death;
89    unsigned len;
90    uint16_t name[0];
91};
92
93struct svcinfo *svclist = 0;
94
95struct svcinfo *find_svc(uint16_t *s16, unsigned len)
96{
97    struct svcinfo *si;
98
99    for (si = svclist; si; si = si->next) {
100        if ((len == si->len) &&
101            !memcmp(s16, si->name, len * sizeof(uint16_t))) {
102            return si;
103        }
104    }
105    return 0;
106}
107
108void svcinfo_death(struct binder_state *bs, void *ptr)
109{
110    struct svcinfo *si = ptr;
111    LOGI("service '%s' died\n", str8(si->name));
112    if (si->ptr) {
113        binder_release(bs, si->ptr);
114        si->ptr = 0;
115    }
116}
117
118uint16_t svcmgr_id[] = {
119    'a','n','d','r','o','i','d','.','o','s','.',
120    'I','S','e','r','v','i','c','e','M','a','n','a','g','e','r'
121};
122
123
124void *do_find_service(struct binder_state *bs, uint16_t *s, unsigned len)
125{
126    struct svcinfo *si;
127    si = find_svc(s, len);
128
129//    LOGI("check_service('%s') ptr = %p\n", str8(s), si ? si->ptr : 0);
130    if (si && si->ptr) {
131        return si->ptr;
132    } else {
133        return 0;
134    }
135}
136
137int do_add_service(struct binder_state *bs,
138                   uint16_t *s, unsigned len,
139                   void *ptr, unsigned uid)
140{
141    struct svcinfo *si;
142//    LOGI("add_service('%s',%p) uid=%d\n", str8(s), ptr, uid);
143
144    if (!ptr || (len == 0) || (len > 127))
145        return -1;
146
147    if (!svc_can_register(uid, s)) {
148        LOGE("add_service('%s',%p) uid=%d - PERMISSION DENIED\n",
149             str8(s), ptr, uid);
150        return -1;
151    }
152
153    si = find_svc(s, len);
154    if (si) {
155        if (si->ptr) {
156            LOGE("add_service('%s',%p) uid=%d - ALREADY REGISTERED\n",
157                 str8(s), ptr, uid);
158            return -1;
159        }
160        si->ptr = ptr;
161    } else {
162        si = malloc(sizeof(*si) + (len + 1) * sizeof(uint16_t));
163        if (!si) {
164            LOGE("add_service('%s',%p) uid=%d - OUT OF MEMORY\n",
165                 str8(s), ptr, uid);
166            return -1;
167        }
168        si->ptr = ptr;
169        si->len = len;
170        memcpy(si->name, s, (len + 1) * sizeof(uint16_t));
171        si->name[len] = '\0';
172        si->death.func = svcinfo_death;
173        si->death.ptr = si;
174        si->next = svclist;
175        svclist = si;
176    }
177
178    binder_acquire(bs, ptr);
179    binder_link_to_death(bs, ptr, &si->death);
180    return 0;
181}
182
183int svcmgr_handler(struct binder_state *bs,
184                   struct binder_txn *txn,
185                   struct binder_io *msg,
186                   struct binder_io *reply)
187{
188    struct svcinfo *si;
189    uint16_t *s;
190    unsigned len;
191    void *ptr;
192
193//    LOGI("target=%p code=%d pid=%d uid=%d\n",
194//         txn->target, txn->code, txn->sender_pid, txn->sender_euid);
195
196    if (txn->target != svcmgr_handle)
197        return -1;
198
199    s = bio_get_string16(msg, &len);
200
201    if ((len != (sizeof(svcmgr_id) / 2)) ||
202        memcmp(svcmgr_id, s, sizeof(svcmgr_id))) {
203        fprintf(stderr,"invalid id %s\n", str8(s));
204        return -1;
205    }
206
207    switch(txn->code) {
208    case SVC_MGR_GET_SERVICE:
209    case SVC_MGR_CHECK_SERVICE:
210        s = bio_get_string16(msg, &len);
211        ptr = do_find_service(bs, s, len);
212        if (!ptr)
213            break;
214        bio_put_ref(reply, ptr);
215        return 0;
216
217    case SVC_MGR_ADD_SERVICE:
218        s = bio_get_string16(msg, &len);
219        ptr = bio_get_ref(msg);
220        if (do_add_service(bs, s, len, ptr, txn->sender_euid))
221            return -1;
222        break;
223
224    case SVC_MGR_LIST_SERVICES: {
225        unsigned n = bio_get_uint32(msg);
226
227        si = svclist;
228        while ((n-- > 0) && si)
229            si = si->next;
230        if (si) {
231            bio_put_string16(reply, si->name);
232            return 0;
233        }
234        return -1;
235    }
236    default:
237        LOGE("unknown code %d\n", txn->code);
238        return -1;
239    }
240
241    bio_put_uint32(reply, 0);
242    return 0;
243}
244
245int main(int argc, char **argv)
246{
247    struct binder_state *bs;
248    void *svcmgr = BINDER_SERVICE_MANAGER;
249
250    bs = binder_open(128*1024);
251
252    if (binder_become_context_manager(bs)) {
253        LOGE("cannot become context manager (%s)\n", strerror(errno));
254        return -1;
255    }
256
257    svcmgr_handle = svcmgr;
258    binder_loop(bs, svcmgr_handler);
259    return 0;
260}
261