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Prevent resetprop function signature duplicate with libc

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topjohnwu 2017-05-30 23:34:39 +08:00
parent 14c5c60863
commit 17d3a87b1f
8 changed files with 156 additions and 932 deletions
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1
jni/Android.mk
View File

@ -34,7 +34,6 @@ LOCAL_SRC_FILES := \
magiskpolicy/sepolicy.c \
magiskpolicy/api.c \
resetprop/resetprop.cpp \
resetprop/libc_logging.cpp \
resetprop/system_properties.cpp \
su/su.c \
su/activity.c \

3
jni/daemon/bootstages.c
View File

@ -693,6 +693,9 @@ void post_fs_data(int client) {
bind_mount(HOSTSFILE, "/system/etc/hosts");
}
// Initialize resetprop for the daemon
init_resetprop();
// Start magiskhide if enabled
char *hide_prop = getprop(MAGISKHIDE_PROP);
if (hide_prop) {

40
jni/resetprop/_system_properties.h
View File

@ -62,38 +62,38 @@ __BEGIN_DECLS
** Map the property area from the specified filename. This
** method is for testing only.
*/
int __system_property_set_filename(const char *filename);
int __system_property_set_filename2(const char *filename);
/*
** Initialize the area to be used to store properties. Can
** only be done by a single process that has write access to
** the property area.
*/
int __system_property_area_init();
int __system_property_area_init2();
/* Read the global serial number of the system properties
**
** Called to predict if a series of cached __system_property_find
** objects will have seen __system_property_serial values change.
** Called to predict if a series of cached __system_property_find2
** objects will have seen __system_property_serial2 values change.
** But also aids the converse, as changes in the global serial can
** also be used to predict if a failed __system_property_find
** also be used to predict if a failed __system_property_find2
** could in-turn now find a new object; thus preventing the
** cycles of effort to poll __system_property_find.
** cycles of effort to poll __system_property_find2.
**
** Typically called at beginning of a cache cycle to signal if _any_ possible
** changes have occurred since last. If there is, one may check each individual
** __system_property_serial to confirm dirty, or __system_property_find
** to check if the property now exists. If a call to __system_property_add
** or __system_property_update has completed between two calls to
** __system_property_area_serial then the second call will return a larger
** __system_property_serial2 to confirm dirty, or __system_property_find2
** to check if the property now exists. If a call to __system_property_add2
** or __system_property_update2 has completed between two calls to
** __system_property_area_serial2 then the second call will return a larger
** value than the first call. Beware of race conditions as changes to the
** properties are not atomic, the main value of this call is to determine
** whether the expensive __system_property_find is worth retrying to see if
** whether the expensive __system_property_find2 is worth retrying to see if
** a property now exists.
**
** Returns the serial number on success, -1 on error.
*/
uint32_t __system_property_area_serial();
uint32_t __system_property_area_serial2();
/* Add a new system property. Can only be done by a single
** process that has write access to the property area, and
@ -103,7 +103,7 @@ uint32_t __system_property_area_serial();
**
** Returns 0 on success, -1 if the property area is full.
*/
int __system_property_add(const char *name, unsigned int namelen, const char *value, unsigned int valuelen);
int __system_property_add2(const char *name, unsigned int namelen, const char *value, unsigned int valuelen);
/* Delete a new system property. Added in resetprop
**
@ -112,21 +112,21 @@ int __system_property_add(const char *name, unsigned int namelen, const char *va
int __system_property_del(const char *name);
/* Update the value of a system property returned by
** __system_property_find. Can only be done by a single process
** __system_property_find2. Can only be done by a single process
** that has write access to the property area, and that process
** must handle sequencing to ensure that only one property is
** updated at a time.
**
** Returns 0 on success, -1 if the parameters are incorrect.
*/
int __system_property_update(prop_info *pi, const char *value, unsigned int len);
int __system_property_update2(prop_info *pi, const char *value, unsigned int len);
/* Read the serial number of a system property returned by
** __system_property_find.
** __system_property_find2.
**
** Returns the serial number on success, -1 on error.
*/
uint32_t __system_property_serial(const prop_info* pi);
uint32_t __system_property_serial2(const prop_info* pi);
/* Initialize the system properties area in read only mode.
* Should be done by all processes that need to read system
@ -134,10 +134,10 @@ uint32_t __system_property_serial(const prop_info* pi);
*
* Returns 0 on success, -1 otherwise.
*/
int __system_properties_init();
int __system_properties_init2();
/* Deprecated: use __system_property_wait instead. */
uint32_t __system_property_wait_any(uint32_t old_serial);
/* Deprecated: use __system_property_wait2 instead. */
uint32_t __system_property_wait_any2(uint32_t old_serial);
__END_DECLS

659
jni/resetprop/libc_logging.cpp
View File

@ -1,659 +0,0 @@
/*
* Copyright (C) 2010 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "libc_logging.h" // Relative path so we can #include this .cpp file for testing.
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <time.h>
#include <unistd.h>
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include "_system_properties.h"
static pthread_mutex_t g_abort_msg_lock = PTHREAD_MUTEX_INITIALIZER;
__LIBC_HIDDEN__ abort_msg_t** __abort_message_ptr; // Accessible to __libc_init_common.
// Must be kept in sync with frameworks/base/core/java/android/util/EventLog.java.
enum AndroidEventLogType {
EVENT_TYPE_INT = 0,
EVENT_TYPE_LONG = 1,
EVENT_TYPE_STRING = 2,
EVENT_TYPE_LIST = 3,
EVENT_TYPE_FLOAT = 4,
};
struct BufferOutputStream {
public:
BufferOutputStream(char* buffer, size_t size) : total(0) {
buffer_ = buffer;
end_ = buffer + size - 1;
pos_ = buffer_;
pos_[0] = '\0';
}
~BufferOutputStream() {
}
void Send(const char* data, int len) {
if (len < 0) {
len = strlen(data);
}
total += len;
while (len > 0) {
int avail = end_ - pos_;
if (avail == 0) {
return;
}
if (avail > len) {
avail = len;
}
memcpy(pos_, data, avail);
pos_ += avail;
pos_[0] = '\0';
len -= avail;
}
}
size_t total;
private:
char* buffer_;
char* pos_;
char* end_;
};
struct FdOutputStream {
public:
FdOutputStream(int fd) : total(0), fd_(fd) {
}
void Send(const char* data, int len) {
if (len < 0) {
len = strlen(data);
}
total += len;
while (len > 0) {
int rc = TEMP_FAILURE_RETRY(write(fd_, data, len));
if (rc == -1) {
return;
}
data += rc;
len -= rc;
}
}
size_t total;
private:
int fd_;
};
/*** formatted output implementation
***/
/* Parse a decimal string from 'format + *ppos',
* return the value, and writes the new position past
* the decimal string in '*ppos' on exit.
*
* NOTE: Does *not* handle a sign prefix.
*/
static unsigned parse_decimal(const char *format, int *ppos) {
const char* p = format + *ppos;
unsigned result = 0;
for (;;) {
int ch = *p;
unsigned d = static_cast<unsigned>(ch - '0');
if (d >= 10U) {
break;
}
result = result*10 + d;
p++;
}
*ppos = p - format;
return result;
}
// Writes number 'value' in base 'base' into buffer 'buf' of size 'buf_size' bytes.
// Assumes that buf_size > 0.
static void format_unsigned(char* buf, size_t buf_size, uint64_t value, int base, bool caps) {
char* p = buf;
char* end = buf + buf_size - 1;
// Generate digit string in reverse order.
while (value) {
unsigned d = value % base;
value /= base;
if (p != end) {
char ch;
if (d < 10) {
ch = '0' + d;
} else {
ch = (caps ? 'A' : 'a') + (d - 10);
}
*p++ = ch;
}
}
// Special case for 0.
if (p == buf) {
if (p != end) {
*p++ = '0';
}
}
*p = '\0';
// Reverse digit string in-place.
size_t length = p - buf;
for (size_t i = 0, j = length - 1; i < j; ++i, --j) {
char ch = buf[i];
buf[i] = buf[j];
buf[j] = ch;
}
}
static void format_integer(char* buf, size_t buf_size, uint64_t value, char conversion) {
// Decode the conversion specifier.
int is_signed = (conversion == 'd' || conversion == 'i' || conversion == 'o');
int base = 10;
if (conversion == 'x' || conversion == 'X') {
base = 16;
} else if (conversion == 'o') {
base = 8;
}
bool caps = (conversion == 'X');
if (is_signed && static_cast<int64_t>(value) < 0) {
buf[0] = '-';
buf += 1;
buf_size -= 1;
value = static_cast<uint64_t>(-static_cast<int64_t>(value));
}
format_unsigned(buf, buf_size, value, base, caps);
}
template <typename Out>
static void SendRepeat(Out& o, char ch, int count) {
char pad[8];
memset(pad, ch, sizeof(pad));
const int pad_size = static_cast<int>(sizeof(pad));
while (count > 0) {
int avail = count;
if (avail > pad_size) {
avail = pad_size;
}
o.Send(pad, avail);
count -= avail;
}
}
/* Perform formatted output to an output target 'o' */
template <typename Out>
static void out_vformat(Out& o, const char* format, va_list args) {
int nn = 0;
for (;;) {
int mm;
int padZero = 0;
int padLeft = 0;
char sign = '\0';
int width = -1;
int prec = -1;
size_t bytelen = sizeof(int);
int slen;
char buffer[32]; /* temporary buffer used to format numbers */
char c;
/* first, find all characters that are not 0 or '%' */
/* then send them to the output directly */
mm = nn;
do {
c = format[mm];
if (c == '\0' || c == '%')
break;
mm++;
} while (1);
if (mm > nn) {
o.Send(format+nn, mm-nn);
nn = mm;
}
/* is this it ? then exit */
if (c == '\0')
break;
/* nope, we are at a '%' modifier */
nn++; // skip it
/* parse flags */
for (;;) {
c = format[nn++];
if (c == '\0') { /* single trailing '%' ? */
c = '%';
o.Send(&c, 1);
return;
}
else if (c == '0') {
padZero = 1;
continue;
}
else if (c == '-') {
padLeft = 1;
continue;
}
else if (c == ' ' || c == '+') {
sign = c;
continue;
}
break;
}
/* parse field width */
if ((c >= '0' && c <= '9')) {
nn --;
width = static_cast<int>(parse_decimal(format, &nn));
c = format[nn++];
}
/* parse precision */
if (c == '.') {
prec = static_cast<int>(parse_decimal(format, &nn));
c = format[nn++];
}
/* length modifier */
switch (c) {
case 'h':
bytelen = sizeof(short);
if (format[nn] == 'h') {
bytelen = sizeof(char);
nn += 1;
}
c = format[nn++];
break;
case 'l':
bytelen = sizeof(long);
if (format[nn] == 'l') {
bytelen = sizeof(long long);
nn += 1;
}
c = format[nn++];
break;
case 'z':
bytelen = sizeof(size_t);
c = format[nn++];
break;
case 't':
bytelen = sizeof(ptrdiff_t);
c = format[nn++];
break;
default:
;
}
/* conversion specifier */
const char* str = buffer;
if (c == 's') {
/* string */
str = va_arg(args, const char*);
if (str == NULL) {
str = "(null)";
}
} else if (c == 'c') {
/* character */
/* NOTE: char is promoted to int when passed through the stack */
buffer[0] = static_cast<char>(va_arg(args, int));
buffer[1] = '\0';
} else if (c == 'p') {
uint64_t value = reinterpret_cast<uintptr_t>(va_arg(args, void*));
buffer[0] = '0';
buffer[1] = 'x';
format_integer(buffer + 2, sizeof(buffer) - 2, value, 'x');
} else if (c == 'd' || c == 'i' || c == 'o' || c == 'u' || c == 'x' || c == 'X') {
/* integers - first read value from stack */
uint64_t value;
int is_signed = (c == 'd' || c == 'i' || c == 'o');
/* NOTE: int8_t and int16_t are promoted to int when passed
* through the stack
*/
switch (bytelen) {
case 1: value = static_cast<uint8_t>(va_arg(args, int)); break;
case 2: value = static_cast<uint16_t>(va_arg(args, int)); break;
case 4: value = va_arg(args, uint32_t); break;
case 8: value = va_arg(args, uint64_t); break;
default: return; /* should not happen */
}
/* sign extension, if needed */
if (is_signed) {
int shift = 64 - 8*bytelen;
value = static_cast<uint64_t>((static_cast<int64_t>(value << shift)) >> shift);
}
/* format the number properly into our buffer */
format_integer(buffer, sizeof(buffer), value, c);
} else if (c == '%') {
buffer[0] = '%';
buffer[1] = '\0';
} else {
__assert(__FILE__, __LINE__, "conversion specifier unsupported");
}
/* if we are here, 'str' points to the content that must be
* outputted. handle padding and alignment now */
slen = strlen(str);
if (sign != '\0' || prec != -1) {
__assert(__FILE__, __LINE__, "sign/precision unsupported");
}
if (slen < width && !padLeft) {
char padChar = padZero ? '0' : ' ';
SendRepeat(o, padChar, width - slen);
}
o.Send(str, slen);
if (slen < width && padLeft) {
char padChar = padZero ? '0' : ' ';
SendRepeat(o, padChar, width - slen);
}
}
}
int __libc_format_buffer(char* buffer, size_t buffer_size, const char* format, ...) {
BufferOutputStream os(buffer, buffer_size);
va_list args;
va_start(args, format);
out_vformat(os, format, args);
va_end(args);
return os.total;
}
int __libc_format_fd(int fd, const char* format, ...) {
FdOutputStream os(fd);
va_list args;
va_start(args, format);
out_vformat(os, format, args);
va_end(args);
return os.total;
}
static int __libc_write_stderr(const char* tag, const char* msg) {
int fd = TEMP_FAILURE_RETRY(open("/dev/stderr", O_CLOEXEC | O_WRONLY | O_APPEND));
if (fd == -1) {
return -1;
}
iovec vec[4];
vec[0].iov_base = const_cast<char*>(tag);
vec[0].iov_len = strlen(tag);
vec[1].iov_base = const_cast<char*>(": ");
vec[1].iov_len = 2;
vec[2].iov_base = const_cast<char*>(msg);
vec[2].iov_len = strlen(msg);
vec[3].iov_base = const_cast<char*>("\n");
vec[3].iov_len = 1;
int result = TEMP_FAILURE_RETRY(writev(fd, vec, 4));
close(fd);
return result;
}
static int __libc_open_log_socket() {
// ToDo: Ideally we want this to fail if the gid of the current
// process is AID_LOGD, but will have to wait until we have
// registered this in private/android_filesystem_config.h. We have
// found that all logd crashes thus far have had no problem stuffing
// the UNIX domain socket and moving on so not critical *today*.
int log_fd = TEMP_FAILURE_RETRY(socket(PF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0));
if (log_fd < 0) {
return -1;
}
if (fcntl(log_fd, F_SETFL, O_NONBLOCK) == -1) {
close(log_fd);
return -1;
}
union {
struct sockaddr addr;
struct sockaddr_un addrUn;
} u;
memset(&u, 0, sizeof(u));
u.addrUn.sun_family = AF_UNIX;
strlcpy(u.addrUn.sun_path, "/dev/socket/logdw", sizeof(u.addrUn.sun_path));
if (TEMP_FAILURE_RETRY(connect(log_fd, &u.addr, sizeof(u.addrUn))) != 0) {
close(log_fd);
return -1;
}
return log_fd;
}
struct cache {
const prop_info* pinfo;
uint32_t serial;
char c;
};
static void refresh_cache(struct cache *cache, const char *key)
{
if (!cache->pinfo) {
cache->pinfo = __system_property_find(key);
if (!cache->pinfo) {
return;
}
}
uint32_t serial = __system_property_serial(cache->pinfo);
if (serial == cache->serial) {
return;
}
cache->serial = serial;
char buf[PROP_VALUE_MAX];
__system_property_read(cache->pinfo, 0, buf);
cache->c = buf[0];
}
// Timestamp state generally remains constant, since a change is
// rare, we can accept a trylock failure gracefully.
static pthread_mutex_t lock_clockid = PTHREAD_MUTEX_INITIALIZER;
static clockid_t __android_log_clockid()
{
static struct cache r_time_cache = { NULL, static_cast<uint32_t>(-1), 0 };
static struct cache p_time_cache = { NULL, static_cast<uint32_t>(-1), 0 };
char c;
if (pthread_mutex_trylock(&lock_clockid)) {
// We are willing to accept some race in this context
if (!(c = p_time_cache.c)) {
c = r_time_cache.c;
}
} else {
static uint32_t serial;
uint32_t current_serial = __system_property_area_serial();
if (current_serial != serial) {
refresh_cache(&r_time_cache, "ro.logd.timestamp");
refresh_cache(&p_time_cache, "persist.logd.timestamp");
serial = current_serial;
}
if (!(c = p_time_cache.c)) {
c = r_time_cache.c;
}
pthread_mutex_unlock(&lock_clockid);
}
return (tolower(c) == 'm') ? CLOCK_MONOTONIC : CLOCK_REALTIME;
}
struct log_time { // Wire format
uint32_t tv_sec;
uint32_t tv_nsec;
};
int __libc_write_log(int priority, const char* tag, const char* msg) {
int main_log_fd = __libc_open_log_socket();
if (main_log_fd == -1) {
// Try stderr instead.
return __libc_write_stderr(tag, msg);
}
iovec vec[6];
char log_id = (priority == ANDROID_LOG_FATAL) ? LOG_ID_CRASH : LOG_ID_MAIN;
vec[0].iov_base = &log_id;
vec[0].iov_len = sizeof(log_id);
uint16_t tid = gettid();
vec[1].iov_base = &tid;
vec[1].iov_len = sizeof(tid);
timespec ts;
clock_gettime(__android_log_clockid(), &ts);
log_time realtime_ts;
realtime_ts.tv_sec = ts.tv_sec;
realtime_ts.tv_nsec = ts.tv_nsec;
vec[2].iov_base = &realtime_ts;
vec[2].iov_len = sizeof(realtime_ts);
vec[3].iov_base = &priority;
vec[3].iov_len = 1;
vec[4].iov_base = const_cast<char*>(tag);
vec[4].iov_len = strlen(tag) + 1;
vec[5].iov_base = const_cast<char*>(msg);
vec[5].iov_len = strlen(msg) + 1;
int result = TEMP_FAILURE_RETRY(writev(main_log_fd, vec, sizeof(vec) / sizeof(vec[0])));
close(main_log_fd);
return result;
}
int __libc_format_log_va_list(int priority, const char* tag, const char* format, va_list args) {
char buffer[1024];
BufferOutputStream os(buffer, sizeof(buffer));
out_vformat(os, format, args);
return __libc_write_log(priority, tag, buffer);
}
int __libc_format_log(int priority, const char* tag, const char* format, ...) {
va_list args;
va_start(args, format);
int result = __libc_format_log_va_list(priority, tag, format, args);
va_end(args);
return result;
}
static int __libc_android_log_event(int32_t tag, char type, const void* payload, size_t len) {
iovec vec[6];
char log_id = LOG_ID_EVENTS;
vec[0].iov_base = &log_id;
vec[0].iov_len = sizeof(log_id);
uint16_t tid = gettid();
vec[1].iov_base = &tid;
vec[1].iov_len = sizeof(tid);
timespec ts;
clock_gettime(__android_log_clockid(), &ts);
log_time realtime_ts;
realtime_ts.tv_sec = ts.tv_sec;
realtime_ts.tv_nsec = ts.tv_nsec;
vec[2].iov_base = &realtime_ts;
vec[2].iov_len = sizeof(realtime_ts);
vec[3].iov_base = &tag;
vec[3].iov_len = sizeof(tag);
vec[4].iov_base = &type;
vec[4].iov_len = sizeof(type);
vec[5].iov_base = const_cast<void*>(payload);
vec[5].iov_len = len;
int event_log_fd = __libc_open_log_socket();
if (event_log_fd == -1) {
return -1;
}
int result = TEMP_FAILURE_RETRY(writev(event_log_fd, vec, sizeof(vec) / sizeof(vec[0])));
close(event_log_fd);
return result;
}
void __libc_android_log_event_int(int32_t tag, int value) {
__libc_android_log_event(tag, EVENT_TYPE_INT, &value, sizeof(value));
}
void __libc_android_log_event_uid(int32_t tag) {
__libc_android_log_event_int(tag, getuid());
}
void __fortify_chk_fail(const char* msg, uint32_t tag) {
if (tag != 0) {
__libc_android_log_event_uid(tag);
}
__libc_fatal("FORTIFY: %s", msg);
}
void __libc_fatal_no_abort(const char* format, ...) {
va_list args;
va_start(args, format);
__libc_fatal(format, args);
va_end(args);
}
void __libc_fatal(const char* format, ...) {
va_list args;
va_start(args, format);
__libc_fatal(format, args);
va_end(args);
abort();
}

115
jni/resetprop/libc_logging.h
View File

@ -1,115 +0,0 @@
/*
* Copyright (C) 2010 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _LIBC_LOGGING_H
#define _LIBC_LOGGING_H
#include <sys/cdefs.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
__BEGIN_DECLS
enum {
ANDROID_LOG_UNKNOWN = 0,
ANDROID_LOG_DEFAULT, /* only for SetMinPriority() */
ANDROID_LOG_VERBOSE,
ANDROID_LOG_DEBUG,
ANDROID_LOG_INFO,
ANDROID_LOG_WARN,
ANDROID_LOG_ERROR,
ANDROID_LOG_FATAL,
ANDROID_LOG_SILENT, /* only for SetMinPriority(); must be last */
};
enum {
LOG_ID_MIN = 0,
LOG_ID_MAIN = 0,
LOG_ID_RADIO = 1,
LOG_ID_EVENTS = 2,
LOG_ID_SYSTEM = 3,
LOG_ID_CRASH = 4,
LOG_ID_MAX
};
struct abort_msg_t {
size_t size;
char msg[0];
};
//
// Formats a message to the log (priority 'fatal'), then aborts.
//
__LIBC_HIDDEN__ __noreturn void __libc_fatal(const char* format, ...) __printflike(1, 2);
//
// Formats a message to the log (priority 'fatal'), but doesn't abort.
// Used by the malloc implementation to ensure that debuggerd dumps memory
// around the bad address.
//
__LIBC_HIDDEN__ void __libc_fatal_no_abort(const char* format, ...)
__printflike(1, 2);
//
// Formatting routines for the C library's internal debugging.
// Unlike the usual alternatives, these don't allocate, and they don't drag in all of stdio.
//
__LIBC_HIDDEN__ int __libc_format_buffer(char* buffer, size_t buffer_size, const char* format, ...)
__printflike(3, 4);
__LIBC_HIDDEN__ int __libc_format_fd(int fd, const char* format, ...)
__printflike(2, 3);
__LIBC_HIDDEN__ int __libc_format_log(int priority, const char* tag, const char* format, ...)
__printflike(3, 4);
__LIBC_HIDDEN__ int __libc_format_log_va_list(int priority, const char* tag, const char* format,
va_list ap);
__LIBC_HIDDEN__ int __libc_write_log(int priority, const char* tag, const char* msg);
//
// Event logging.
//
__LIBC_HIDDEN__ void __libc_android_log_event_int(int32_t tag, int value);
__LIBC_HIDDEN__ void __libc_android_log_event_uid(int32_t tag);
__LIBC_HIDDEN__ __noreturn void __fortify_chk_fail(const char* msg, uint32_t event_tag);
__END_DECLS
#endif

18
jni/resetprop/resetprop.cpp
View File

@ -11,7 +11,7 @@
*
* Functions that need to be patched/added in system_properties.cpp
*
* int __system_properties_init()
* int __system_properties_init2()
* on android 7, first tear down the everything then let it initialize again:
* if (initialized) {
* //list_foreach(contexts, [](context_node* l) { l->reset_access(); });
@ -123,7 +123,7 @@ static int usage(char* arg0) {
int init_resetprop() {
PRINT_D("resetprop: Initializing...\n");
if (__system_properties_init()) {
if (__system_properties_init2()) {
PRINT_E("resetprop: Initialize error\n");
return -1;
}
@ -136,12 +136,12 @@ static void read_prop_info(void* cookie, const char *name, const char *value, ui
// Get prop by name, return string (should free manually!)
char *getprop(const char *name) {
const prop_info *pi = __system_property_find(name);
const prop_info *pi = __system_property_find2(name);
if (pi == NULL) {
return NULL;
}
char value[PROP_VALUE_MAX];
__system_property_read_callback(pi, read_prop_info, value);
__system_property_read_callback2(pi, read_prop_info, value);
PRINT_D("resetprop: getprop [%s]: [%s]\n", name, value);
return strdup(value);
}
@ -158,16 +158,16 @@ int setprop2(const char *name, const char *value, const int trigger) {
free(check);
if (trigger) {
if (!strncmp(name, "ro.", 3)) deleteprop(name);
ret = __system_property_set(name, value);
ret = __system_property_set2(name, value);
} else {
ret = __system_property_update((prop_info*) __system_property_find(name), value, strlen(value));
ret = __system_property_update2((prop_info*) __system_property_find2(name), value, strlen(value));
}
} else {
PRINT_D("resetprop: New prop [%s]\n", name);
if (trigger) {
ret = __system_property_set(name, value);
ret = __system_property_set2(name, value);
} else {
ret = __system_property_add(name, strlen(name), value, strlen(value));
ret = __system_property_add2(name, strlen(name), value, strlen(value));
}
}
@ -276,6 +276,8 @@ int resetprop_main(int argc, char *argv[]) {
}
}
init_resetprop();
if (file) {
return read_prop_file(filename, trigger);
} else if (del) {

222
jni/resetprop/system_properties.cpp
View File

@ -54,11 +54,12 @@
#include "_system_properties.h"
#include "system_properties.h"
// #include <async_safe/log.h>
#include "ErrnoRestorer.h"
#include "bionic_futex.h"
#include "bionic_lock.h"
#include "bionic_macros.h"
#include "libc_logging.h"
static constexpr int PROP_FILENAME_MAX = 1024;
@ -90,6 +91,16 @@ static const char* kServiceVersionPropertyName = "ro.property_service.version";
* +-----+ +-----+ +-----+ +===========+
*/
// This is a alternative implementation for async_safe_format_buffer
// A workaround to not include the async_safe header
static int async_safe_format_buffer(char * s, size_t n, const char * format, ...) {
va_list vl;
va_start(vl, format);
int ret = vsnprintf(s, n, format, vl);
va_end(vl);
return ret;
}
// Represents a node in the trie.
struct prop_bt {
uint32_t namelen;
@ -202,17 +213,9 @@ struct prop_info {
DISALLOW_IMPLICIT_CONSTRUCTORS(prop_info);
};
struct find_nth_cookie {
uint32_t count;
const uint32_t n;
const prop_info* pi;
explicit find_nth_cookie(uint32_t n) : count(0), n(n), pi(nullptr) {
}
};
// This is public because it was exposed in the NDK. As of 2017-01, ~60 apps reference this symbol.
prop_area* __system_property_area__ = nullptr;
// Change to static, we don't want to use the global libc reference
static prop_area* __system_property_area__ = nullptr;
static char property_filename[PROP_FILENAME_MAX] = PROP_FILENAME;
static size_t pa_data_size;
@ -238,8 +241,8 @@ static prop_area* map_prop_area_rw(const char* filename, const char* context,
if (context) {
if (fsetxattr(fd, XATTR_NAME_SELINUX, context, strlen(context) + 1, 0) != 0) {
__libc_format_log(ANDROID_LOG_ERROR, "libc",
"fsetxattr failed to set context (%s) for \"%s\"", context, filename);
// async_safe_format_log(ANDROID_LOG_ERROR, "libc",
// "fsetxattr failed to set context (%s) for \"%s\"", context, filename);
/*
* fsetxattr() will fail during system properties tests due to selinux policy.
* We do not want to create a custom policy for the tester, so we will continue in
@ -694,9 +697,9 @@ static int send_prop_msg(const prop_msg* msg) {
// ms so callers who do read-after-write can reliably see
// what they've written. Most of the time.
// TODO: fix the system properties design.
__libc_format_log(ANDROID_LOG_WARN, "libc",
"Property service has timed out while trying to set \"%s\" to \"%s\"",
msg->name, msg->value);
// async_safe_format_log(ANDROID_LOG_WARN, "libc",
// "Property service has timed out while trying to set \"%s\" to \"%s\"",
// msg->name, msg->value);
result = 0;
}
}
@ -704,14 +707,6 @@ static int send_prop_msg(const prop_msg* msg) {
return result;
}
static void find_nth_fn(const prop_info* pi, void* ptr) {
find_nth_cookie* cookie = reinterpret_cast<find_nth_cookie*>(ptr);
if (cookie->n == cookie->count) cookie->pi = pi;
cookie->count++;
}
bool prop_area::foreach_property(prop_bt* const trie,
void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
if (!trie) return false;
@ -872,7 +867,8 @@ bool context_node::open(bool access_rw, bool* fsetxattr_failed) {
}
char filename[PROP_FILENAME_MAX];
int len = __libc_format_buffer(filename, sizeof(filename), "%s/%s", property_filename, context_);
int len = async_safe_format_buffer(filename, sizeof(filename), "%s/%s", property_filename,
context_);
if (len < 0 || len > PROP_FILENAME_MAX) {
lock_.unlock();
return false;
@ -907,7 +903,8 @@ void context_node::reset_access() {
bool context_node::check_access() {
char filename[PROP_FILENAME_MAX];
int len = __libc_format_buffer(filename, sizeof(filename), "%s/%s", property_filename, context_);
int len = async_safe_format_buffer(filename, sizeof(filename), "%s/%s", property_filename,
context_);
if (len < 0 || len > PROP_FILENAME_MAX) {
return false;
}
@ -930,7 +927,8 @@ void context_node::unmap() {
static bool map_system_property_area(bool access_rw, bool* fsetxattr_failed) {
char filename[PROP_FILENAME_MAX];
int len =
__libc_format_buffer(filename, sizeof(filename), "%s/properties_serial", property_filename);
async_safe_format_buffer(filename, sizeof(filename), "%s/properties_serial",
property_filename);
if (len < 0 || len > PROP_FILENAME_MAX) {
__system_property_area__ = nullptr;
return false;
@ -1145,7 +1143,7 @@ static void free_and_unmap_contexts() {
}
}
int __system_properties_init() {
int __system_properties_init2() {
// This is called from __libc_init_common, and should leave errno at 0 (http://b/37248982).
ErrnoRestorer errno_restorer;
@ -1175,7 +1173,7 @@ int __system_properties_init() {
return 0;
}
int __system_property_set_filename(const char* filename) {
int __system_property_set_filename2(const char* filename) {
size_t len = strlen(filename);
if (len >= sizeof(property_filename)) return -1;
@ -1183,7 +1181,7 @@ int __system_property_set_filename(const char* filename) {
return 0;
}
int __system_property_area_init() {
int __system_property_area_init2() {
free_and_unmap_contexts();
mkdir(property_filename, S_IRWXU | S_IXGRP | S_IXOTH);
if (!initialize_properties()) {
@ -1204,23 +1202,23 @@ int __system_property_area_init() {
return fsetxattr_failed ? -2 : 0;
}
uint32_t __system_property_area_serial() {
uint32_t __system_property_area_serial2() {
prop_area* pa = __system_property_area__;
if (!pa) {
return -1;
}
// Make sure this read fulfilled before __system_property_serial
// Make sure this read fulfilled before __system_property_serial2
return atomic_load_explicit(pa->serial(), memory_order_acquire);
}
const prop_info* __system_property_find(const char* name) {
const prop_info* __system_property_find2(const char* name) {
if (!__system_property_area__) {
return nullptr;
}
prop_area* pa = get_prop_area_for_name(name);
if (!pa) {
__libc_format_log(ANDROID_LOG_ERROR, "libc", "Access denied finding property \"%s\"", name);
// async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied finding property \"%s\"", name);
return nullptr;
}
@ -1234,7 +1232,6 @@ int __system_property_del(const char *name) {
prop_area* pa = get_prop_area_for_name(name);
if (!pa) {
__libc_format_log(ANDROID_LOG_ERROR, "libc", "Access denied finding property \"%s\"", name);
return 1;
}
@ -1257,9 +1254,9 @@ static inline uint_least32_t load_const_atomic(const atomic_uint_least32_t* s, m
return atomic_load_explicit(non_const_s, mo);
}
int __system_property_read(const prop_info* pi, char* name, char* value) {
int __system_property_read2(const prop_info* pi, char* name, char* value) {
while (true) {
uint32_t serial = __system_property_serial(pi); // acquire semantics
uint32_t serial = __system_property_serial2(pi); // acquire semantics
size_t len = SERIAL_VALUE_LEN(serial);
memcpy(value, pi->value, len + 1);
// TODO: Fix the synchronization scheme here.
@ -1274,34 +1271,34 @@ int __system_property_read(const prop_info* pi, char* name, char* value) {
if (serial == load_const_atomic(&(pi->serial), memory_order_relaxed)) {
if (name != nullptr) {
size_t namelen = strlcpy(name, pi->name, PROP_NAME_MAX);
if (namelen >= PROP_NAME_MAX) {
__libc_format_log(ANDROID_LOG_ERROR, "libc",
"The property name length for \"%s\" is >= %d;"
" please use __system_property_read_callback"
" to read this property. (the name is truncated to \"%s\")",
pi->name, PROP_NAME_MAX - 1, name);
}
// if (namelen >= PROP_NAME_MAX) {
// async_safe_format_log(ANDROID_LOG_ERROR, "libc",
// "The property name length for \"%s\" is >= %d;"
// " please use __system_property_read_callback2"
// " to read this property. (the name is truncated to \"%s\")",
// pi->name, PROP_NAME_MAX - 1, name);
// }
}
return len;
}
}
}
void __system_property_read_callback(const prop_info* pi,
void __system_property_read_callback2(const prop_info* pi,
void (*callback)(void* cookie,
const char* name,
const char* value,
uint32_t serial),
void* cookie) {
while (true) {
uint32_t serial = __system_property_serial(pi); // acquire semantics
uint32_t serial = __system_property_serial2(pi); // acquire semantics
size_t len = SERIAL_VALUE_LEN(serial);
char value_buf[len + 1];
memcpy(value_buf, pi->value, len);
value_buf[len] = '\0';
// TODO: see todo in __system_property_read function
// TODO: see todo in __system_property_read2 function
atomic_thread_fence(memory_order_acquire);
if (serial == load_const_atomic(&(pi->serial), memory_order_relaxed)) {
callback(cookie, pi->name, value_buf, serial);
@ -1310,11 +1307,11 @@ void __system_property_read_callback(const prop_info* pi,
}
}
int __system_property_get(const char* name, char* value) {
const prop_info* pi = __system_property_find(name);
int __system_property_get2(const char* name, char* value) {
const prop_info* pi = __system_property_find2(name);
if (pi != 0) {
return __system_property_read(pi, nullptr, value);
return __system_property_read2(pi, nullptr, value);
} else {
value[0] = 0;
return 0;
@ -1328,25 +1325,25 @@ static atomic_uint_least32_t g_propservice_protocol_version = 0;
static void detect_protocol_version() {
char value[PROP_VALUE_MAX];
if (__system_property_get(kServiceVersionPropertyName, value) == 0) {
if (__system_property_get2(kServiceVersionPropertyName, value) == 0) {
g_propservice_protocol_version = kProtocolVersion1;
__libc_format_log(ANDROID_LOG_WARN, "libc",
"Using old property service protocol (\"%s\" is not set)",
kServiceVersionPropertyName);
// async_safe_format_log(ANDROID_LOG_WARN, "libc",
// "Using old property service protocol (\"%s\" is not set)",
// kServiceVersionPropertyName);
} else {
uint32_t version = static_cast<uint32_t>(atoll(value));
if (version >= kProtocolVersion2) {
g_propservice_protocol_version = kProtocolVersion2;
} else {
__libc_format_log(ANDROID_LOG_WARN, "libc",
"Using old property service protocol (\"%s\"=\"%s\")",
kServiceVersionPropertyName, value);
// async_safe_format_log(ANDROID_LOG_WARN, "libc",
// "Using old property service protocol (\"%s\"=\"%s\")",
// kServiceVersionPropertyName, value);
g_propservice_protocol_version = kProtocolVersion1;
}
}
}
int __system_property_set(const char* key, const char* value) {
int __system_property_set2(const char* key, const char* value) {
if (key == nullptr) return -1;
if (value == nullptr) value = "";
if (strlen(value) >= PROP_VALUE_MAX) return -1;
@ -1370,50 +1367,50 @@ int __system_property_set(const char* key, const char* value) {
// Use proper protocol
PropertyServiceConnection connection;
if (!connection.IsValid()) {
errno = connection.GetLastError();
__libc_format_log(ANDROID_LOG_WARN,
"libc",
"Unable to set property \"%s\" to \"%s\": connection failed; errno=%d (%s)",
key,
value,
errno,
strerror(errno));
// errno = connection.GetLastError();
// async_safe_format_log(ANDROID_LOG_WARN,
// "libc",
// "Unable to set property \"%s\" to \"%s\": connection failed; errno=%d (%s)",
// key,
// value,
// errno,
// strerror(errno));
return -1;
}
SocketWriter writer(&connection);
if (!writer.WriteUint32(PROP_MSG_SETPROP2).WriteString(key).WriteString(value).Send()) {
errno = connection.GetLastError();
__libc_format_log(ANDROID_LOG_WARN,
"libc",
"Unable to set property \"%s\" to \"%s\": write failed; errno=%d (%s)",
key,
value,
errno,
strerror(errno));
// errno = connection.GetLastError();
// async_safe_format_log(ANDROID_LOG_WARN,
// "libc",
// "Unable to set property \"%s\" to \"%s\": write failed; errno=%d (%s)",
// key,
// value,
// errno,
// strerror(errno));
return -1;
}
int result = -1;
if (!connection.RecvInt32(&result)) {
errno = connection.GetLastError();
__libc_format_log(ANDROID_LOG_WARN,
"libc",
"Unable to set property \"%s\" to \"%s\": recv failed; errno=%d (%s)",
key,
value,
errno,
strerror(errno));
// errno = connection.GetLastError();
// async_safe_format_log(ANDROID_LOG_WARN,
// "libc",
// "Unable to set property \"%s\" to \"%s\": recv failed; errno=%d (%s)",
// key,
// value,
// errno,
// strerror(errno));
return -1;
}
if (result != PROP_SUCCESS) {
__libc_format_log(ANDROID_LOG_WARN,
"libc",
"Unable to set property \"%s\" to \"%s\": error code: 0x%x",
key,
value,
result);
// async_safe_format_log(ANDROID_LOG_WARN,
// "libc",
// "Unable to set property \"%s\" to \"%s\": error code: 0x%x",
// key,
// value,
// result);
return -1;
}
@ -1421,7 +1418,7 @@ int __system_property_set(const char* key, const char* value) {
}
}
int __system_property_update(prop_info* pi, const char* value, unsigned int len) {
int __system_property_update2(prop_info* pi, const char* value, unsigned int len) {
if (len >= PROP_VALUE_MAX) {
return -1;
}
@ -1451,7 +1448,7 @@ int __system_property_update(prop_info* pi, const char* value, unsigned int len)
return 0;
}
int __system_property_add(const char* name, unsigned int namelen, const char* value,
int __system_property_add2(const char* name, unsigned int namelen, const char* value,
unsigned int valuelen) {
if (valuelen >= PROP_VALUE_MAX) {
return -1;
@ -1468,7 +1465,7 @@ int __system_property_add(const char* name, unsigned int namelen, const char* va
prop_area* pa = get_prop_area_for_name(name);
if (!pa) {
__libc_format_log(ANDROID_LOG_ERROR, "libc", "Access denied adding property \"%s\"", name);
// async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied adding property \"%s\"", name);
return -1;
}
@ -1488,7 +1485,7 @@ int __system_property_add(const char* name, unsigned int namelen, const char* va
}
// Wait for non-locked serial, and retrieve it with acquire semantics.
uint32_t __system_property_serial(const prop_info* pi) {
uint32_t __system_property_serial2(const prop_info* pi) {
uint32_t serial = load_const_atomic(&pi->serial, memory_order_acquire);
while (SERIAL_DIRTY(serial)) {
__futex_wait(const_cast<_Atomic(uint_least32_t)*>(&pi->serial), serial, nullptr);
@ -1497,13 +1494,13 @@ uint32_t __system_property_serial(const prop_info* pi) {
return serial;
}
uint32_t __system_property_wait_any(uint32_t old_serial) {
uint32_t __system_property_wait_any2(uint32_t old_serial) {
uint32_t new_serial;
__system_property_wait(nullptr, old_serial, &new_serial, nullptr);
__system_property_wait2(nullptr, old_serial, &new_serial, nullptr);
return new_serial;
}
bool __system_property_wait(const prop_info* pi,
bool __system_property_wait2(const prop_info* pi,
uint32_t old_serial,
uint32_t* new_serial_ptr,
const timespec* relative_timeout) {
@ -1529,33 +1526,30 @@ bool __system_property_wait(const prop_info* pi,
return true;
}
/* Deprecated, we won't use it anyways */
const prop_info* __system_property_find_nth2(unsigned n) {
struct find_nth {
const uint32_t sought;
uint32_t current;
const prop_info* result;
// const prop_info* __system_property_find_nth(unsigned n) {
// if (bionic_get_application_target_sdk_version() >= __ANDROID_API_O__) {
// __libc_fatal(
// "__system_property_find_nth is not supported since Android O,"
// " please use __system_property_foreach instead.");
// }
explicit find_nth(uint32_t n) : sought(n), current(0), result(nullptr) {}
static void fn(const prop_info* pi, void* ptr) {
find_nth* self = reinterpret_cast<find_nth*>(ptr);
if (self->current++ == self->sought) self->result = pi;
}
} state(n);
__system_property_foreach2(find_nth::fn, &state);
return state.result;
}
// find_nth_cookie cookie(n);
// const int err = __system_property_foreach(find_nth_fn, &cookie);
// if (err < 0) {
// return nullptr;
// }
// return cookie.pi;
// }
int __system_property_foreach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
int __system_property_foreach2(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
if (!__system_property_area__) {
return -1;
}
list_foreach(contexts, [propfn, cookie](context_node* l) {
if (l->check_access_and_open()) {
l->pa()->foreach (propfn, cookie);
l->pa()->foreach(propfn, cookie);
}
});
return 0;

30
jni/resetprop/system_properties.h
View File

@ -43,30 +43,30 @@ typedef struct prop_info prop_info;
/*
* Sets system property `key` to `value`, creating the system property if it doesn't already exist.
*/
int __system_property_set(const char* key, const char* value) __INTRODUCED_IN(12);
int __system_property_set2(const char* key, const char* value) __INTRODUCED_IN(12);
/*
* Returns a `prop_info` corresponding system property `name`, or nullptr if it doesn't exist.
* Use __system_property_read_callback to query the current value.
* Use __system_property_read_callback2 to query the current value.
*
* Property lookup is expensive, so it can be useful to cache the result of this function.
*/
const prop_info* __system_property_find(const char* name);
const prop_info* __system_property_find2(const char* name);
/*
* Calls `callback` with a consistent trio of name, value, and serial number for property `pi`.
*/
void __system_property_read_callback(const prop_info *pi,
void __system_property_read_callback2(const prop_info *pi,
void (*callback)(void* cookie, const char *name, const char *value, uint32_t serial),
void* cookie) __INTRODUCED_IN_FUTURE;
void* cookie) __INTRODUCED_IN(26);
/*
* Passes a `prop_info` for each system property to the provided
* callback. Use __system_property_read_callback() to read the value.
* callback. Use __system_property_read_callback2() to read the value.
*
* This method is for inspecting and debugging the property system, and not generally useful.
*/
int __system_property_foreach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie)
int __system_property_foreach2(void (*propfn)(const prop_info* pi, void* cookie), void* cookie)
__INTRODUCED_IN(19);
/*
@ -82,20 +82,20 @@ int __system_property_foreach(void (*propfn)(const prop_info* pi, void* cookie),
* timed out.
*/
struct timespec;
bool __system_property_wait(const prop_info* pi,
bool __system_property_wait2(const prop_info* pi,
uint32_t old_serial,
uint32_t* new_serial_ptr,
const struct timespec* relative_timeout)
__INTRODUCED_IN_FUTURE;
__INTRODUCED_IN(26);
/* Deprecated. In Android O and above, there's no limit on property name length. */
#define PROP_NAME_MAX 32
/* Deprecated. Use __system_property_read_callback instead. */
int __system_property_read(const prop_info *pi, char *name, char *value);
/* Deprecated. Use __system_property_read_callback instead. */
int __system_property_get(const char *name, char *value);
/* Deprecated. Use __system_property_foreach instead. Aborts in Android O and above. */
const prop_info *__system_property_find_nth(unsigned n) __REMOVED_IN(26);
/* Deprecated. Use __system_property_read_callback2 instead. */
int __system_property_read2(const prop_info* pi, char* name, char* value);
/* Deprecated. Use __system_property_read_callback2 instead. */
int __system_property_get2(const char* name, char* value);
/* Deprecated. Use __system_property_foreach2 instead. */
const prop_info* __system_property_find_nth2(unsigned n);
__END_DECLS