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
29 /*
30 * This file is only used to provide backwards compatibility to property areas
31 * created by old versions of init, which occurs when an ota runs. The updater
32 * binary is compiled statically against the newest bionic, but the recovery
33 * ramdisk may be using an old version of init. This can all be removed once
34 * OTAs from pre-K versions are no longer supported.
35 */
36
37 #include <string.h>
38 #include <sys/atomics.h>
39
40 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
41 #include <sys/_system_properties.h>
42
43 #define TOC_NAME_LEN(toc) ((toc) >> 24)
44 #define TOC_TO_INFO(area, toc) ((prop_info_compat*) (((char*) area) + ((toc) & 0xFFFFFF)))
45
46 struct prop_area_compat {
47 unsigned volatile count;
48 unsigned volatile serial;
49 unsigned magic;
50 unsigned version;
51 unsigned toc[1];
52 };
53
54 typedef struct prop_area_compat prop_area_compat;
55
56 struct prop_area;
57 typedef struct prop_area prop_area;
58
59 struct prop_info_compat {
60 char name[PROP_NAME_MAX];
61 unsigned volatile serial;
62 char value[PROP_VALUE_MAX];
63 };
64
65 typedef struct prop_info_compat prop_info_compat;
66
67 extern prop_area *__system_property_area__;
68
__system_property_find_compat(const char * name)69 const prop_info *__system_property_find_compat(const char *name)
70 {
71 prop_area_compat *pa = (prop_area_compat *)__system_property_area__;
72 unsigned count = pa->count;
73 unsigned *toc = pa->toc;
74 unsigned len = strlen(name);
75 prop_info_compat *pi;
76
77 if (len >= PROP_NAME_MAX)
78 return 0;
79 if (len < 1)
80 return 0;
81
82 while(count--) {
83 unsigned entry = *toc++;
84 if(TOC_NAME_LEN(entry) != len) continue;
85
86 pi = TOC_TO_INFO(pa, entry);
87 if(memcmp(name, pi->name, len)) continue;
88
89 return (const prop_info *)pi;
90 }
91
92 return 0;
93 }
94
__system_property_read_compat(const prop_info * _pi,char * name,char * value)95 int __system_property_read_compat(const prop_info *_pi, char *name, char *value)
96 {
97 unsigned serial, len;
98 const prop_info_compat *pi = (const prop_info_compat *)_pi;
99
100 for(;;) {
101 serial = pi->serial;
102 while(SERIAL_DIRTY(serial)) {
103 __futex_wait((volatile void *)&pi->serial, serial, 0);
104 serial = pi->serial;
105 }
106 len = SERIAL_VALUE_LEN(serial);
107 memcpy(value, pi->value, len + 1);
108 if(serial == pi->serial) {
109 if(name != 0) {
110 strcpy(name, pi->name);
111 }
112 return len;
113 }
114 }
115 }
116
__system_property_foreach_compat(void (* propfn)(const prop_info * pi,void * cookie),void * cookie)117 int __system_property_foreach_compat(
118 void (*propfn)(const prop_info *pi, void *cookie),
119 void *cookie)
120 {
121 prop_area_compat *pa = (prop_area_compat *)__system_property_area__;
122 unsigned i;
123
124 for (i = 0; i < pa->count; i++) {
125 unsigned entry = pa->toc[i];
126 prop_info_compat *pi = TOC_TO_INFO(pa, entry);
127 propfn((const prop_info *)pi, cookie);
128 }
129
130 return 0;
131 }
132