1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <unistd.h>
31 #include <stddef.h>
32 #include <errno.h>
33
34 #include <sys/mman.h>
35
36 #include <sys/socket.h>
37 #include <sys/un.h>
38 #include <sys/select.h>
39 #include <sys/types.h>
40 #include <netinet/in.h>
41
42 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
43 #include <sys/_system_properties.h>
44
45 #include <sys/atomics.h>
46
47 static const char property_service_name[] = PROP_SERVICE_NAME;
48
49 static unsigned dummy_props = 0;
50
51 prop_area *__system_property_area__ = (void*) &dummy_props;
52
__system_properties_init(void)53 int __system_properties_init(void)
54 {
55 prop_area *pa;
56 int s, fd;
57 unsigned sz;
58 char *env;
59
60 if(__system_property_area__ != ((void*) &dummy_props)) {
61 return 0;
62 }
63
64 env = getenv("ANDROID_PROPERTY_WORKSPACE");
65 if (!env) {
66 return -1;
67 }
68 fd = atoi(env);
69 env = strchr(env, ',');
70 if (!env) {
71 return -1;
72 }
73 sz = atoi(env + 1);
74
75 pa = mmap(0, sz, PROT_READ, MAP_SHARED, fd, 0);
76
77 if(pa == MAP_FAILED) {
78 return -1;
79 }
80
81 if((pa->magic != PROP_AREA_MAGIC) || (pa->version != PROP_AREA_VERSION)) {
82 munmap(pa, sz);
83 return -1;
84 }
85
86 __system_property_area__ = pa;
87 return 0;
88 }
89
__system_property_find_nth(unsigned n)90 const prop_info *__system_property_find_nth(unsigned n)
91 {
92 prop_area *pa = __system_property_area__;
93
94 if(n >= pa->count) {
95 return 0;
96 } else {
97 return TOC_TO_INFO(pa, pa->toc[n]);
98 }
99 }
100
__system_property_find(const char * name)101 const prop_info *__system_property_find(const char *name)
102 {
103 prop_area *pa = __system_property_area__;
104 unsigned count = pa->count;
105 unsigned *toc = pa->toc;
106 unsigned len = strlen(name);
107 prop_info *pi;
108
109 while(count--) {
110 unsigned entry = *toc++;
111 if(TOC_NAME_LEN(entry) != len) continue;
112
113 pi = TOC_TO_INFO(pa, entry);
114 if(memcmp(name, pi->name, len)) continue;
115
116 return pi;
117 }
118
119 return 0;
120 }
121
__system_property_read(const prop_info * pi,char * name,char * value)122 int __system_property_read(const prop_info *pi, char *name, char *value)
123 {
124 unsigned serial, len;
125
126 for(;;) {
127 serial = pi->serial;
128 while(SERIAL_DIRTY(serial)) {
129 __futex_wait(&pi->serial, serial, 0);
130 serial = pi->serial;
131 }
132 len = SERIAL_VALUE_LEN(serial);
133 memcpy(value, pi->value, len + 1);
134 if(serial == pi->serial) {
135 if(name != 0) {
136 strcpy(name, pi->name);
137 }
138 return len;
139 }
140 }
141 }
142
__system_property_get(const char * name,char * value)143 int __system_property_get(const char *name, char *value)
144 {
145 const prop_info *pi = __system_property_find(name);
146
147 if(pi != 0) {
148 return __system_property_read(pi, 0, value);
149 } else {
150 value[0] = 0;
151 return 0;
152 }
153 }
154
__system_property_wait(const prop_info * pi)155 int __system_property_wait(const prop_info *pi)
156 {
157 unsigned n;
158 if(pi == 0) {
159 prop_area *pa = __system_property_area__;
160 n = pa->serial;
161 do {
162 __futex_wait(&pa->serial, n, 0);
163 } while(n == pa->serial);
164 } else {
165 n = pi->serial;
166 do {
167 __futex_wait(&pi->serial, n, 0);
168 } while(n == pi->serial);
169 }
170 return 0;
171 }
172