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      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  */
     26 static 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 
     51 void *svcmgr_handle;
     52 
     53 const 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 
     68 int 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 
     77 int 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 
     91 struct 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 
    101 struct svcinfo *svclist = 0;
    102 
    103 struct 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 
    116 void 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 
    126 uint16_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 
    132 void *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 
    153 int 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 
    201 int 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 
    270 int 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