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Merge "Add __system_property_wait and return the serial in __system_property_read_callback."

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Treehugger Robot 2017-02-14 03:48:23 +00:00 committed by Gerrit Code Review
commit ade3be476f
12 changed files with 148 additions and 121 deletions
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40
libc/bionic/system_properties.cpp
View file

@ -1102,7 +1102,7 @@ int __system_property_area_init() {
return fsetxattr_failed ? -2 : 0;
}
unsigned int __system_property_area_serial() {
uint32_t __system_property_area_serial() {
prop_area* pa = __system_property_area__;
if (!pa) {
return -1;
@ -1163,8 +1163,10 @@ int __system_property_read(const prop_info* pi, char* name, char* value) {
}
void __system_property_read_callback(const prop_info* pi,
void (*callback)(void* cookie, const char* name,
const char* value),
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
@ -1177,7 +1179,7 @@ void __system_property_read_callback(const prop_info* pi,
// TODO: see todo in __system_property_read function
atomic_thread_fence(memory_order_acquire);
if (serial == load_const_atomic(&(pi->serial), memory_order_relaxed)) {
callback(cookie, pi->name, value_buf);
callback(cookie, pi->name, value_buf, serial);
return;
}
}
@ -1329,30 +1331,34 @@ int __system_property_add(const char* name, unsigned int namelen, const char* va
}
// Wait for non-locked serial, and retrieve it with acquire semantics.
unsigned int __system_property_serial(const prop_info* pi) {
uint32_t __system_property_serial(const prop_info* pi) {
uint32_t serial = load_const_atomic(&pi->serial, memory_order_acquire);
while (SERIAL_DIRTY(serial)) {
__futex_wait(const_cast<volatile void*>(reinterpret_cast<const void*>(&pi->serial)), serial,
nullptr);
__futex_wait(const_cast<_Atomic(uint_least32_t)*>(&pi->serial), serial, nullptr);
serial = load_const_atomic(&pi->serial, memory_order_acquire);
}
return serial;
}
unsigned int __system_property_wait_any(unsigned int serial) {
uint32_t __system_property_wait_any(uint32_t old_serial) {
prop_area* pa = __system_property_area__;
uint32_t my_serial;
if (!pa) {
return 0;
}
if (!pa) return 0;
uint32_t new_serial;
do {
__futex_wait(pa->serial(), serial, nullptr);
my_serial = atomic_load_explicit(pa->serial(), memory_order_acquire);
} while (my_serial == serial);
__futex_wait(pa->serial(), old_serial, nullptr);
new_serial = atomic_load_explicit(pa->serial(), memory_order_acquire);
} while (new_serial == old_serial);
return new_serial;
}
return my_serial;
uint32_t __system_property_wait(const prop_info* pi, uint32_t old_serial) {
uint32_t new_serial;
do {
__futex_wait(const_cast<_Atomic(uint_least32_t)*>(&pi->serial), old_serial, nullptr);
new_serial = load_const_atomic(&pi->serial, memory_order_acquire);
} while (new_serial == old_serial);
return new_serial;
}
const prop_info* __system_property_find_nth(unsigned n) {

23
libc/include/sys/_system_properties.h
View file

@ -30,6 +30,7 @@
#define _INCLUDE_SYS__SYSTEM_PROPERTIES_H
#include <sys/cdefs.h>
#include <stdint.h>
#ifndef _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#error you should #include <sys/system_properties.h> instead
@ -91,7 +92,7 @@ int __system_property_area_init();
**
** Returns the serial number on success, -1 on error.
*/
unsigned int __system_property_area_serial();
uint32_t __system_property_area_serial();
/* Add a new system property. Can only be done by a single
** process that has write access to the property area, and
@ -118,12 +119,22 @@ int __system_property_update(prop_info *pi, const char *value, unsigned int len)
**
** Returns the serial number on success, -1 on error.
*/
unsigned int __system_property_serial(const prop_info *pi);
uint32_t __system_property_serial(const prop_info* pi);
/* Wait for any system property to be updated. Caller must pass
** in 0 the first time, and the previous return value on each
** successive call. */
unsigned int __system_property_wait_any(unsigned int serial);
/*
* Waits for any system property to be updated past `old_serial`.
* If you don't know the current global serial number, use 0.
* Returns the new global serial number.
*/
uint32_t __system_property_wait_any(uint32_t old_serial);
/*
* Waits for the specific system property identified by `pi` to be updated past `old_serial`.
* If you don't know the current serial, use 0.
* Returns the serial number for `pi` that caused the wake.
*/
uint32_t __system_property_wait(const prop_info* pi, uint32_t old_serial)
__INTRODUCED_IN_FUTURE;
/* Initialize the system properties area in read only mode.
* Should be done by all processes that need to read system

87
libc/include/sys/system_properties.h
View file

@ -31,77 +31,52 @@
#include <sys/cdefs.h>
#include <stddef.h>
#include <stdint.h>
__BEGIN_DECLS
typedef struct prop_info prop_info;
#define PROP_NAME_MAX 32
#define PROP_VALUE_MAX 92
/* Look up a system property by name, copying its value and a
** \0 terminator to the provided pointer. The total bytes
** copied will be no greater than PROP_VALUE_MAX. Returns
** the string length of the value. A property that is not
** defined is identical to a property with a length 0 value.
*/
int __system_property_get(const char *name, char *value);
/* Set a system property by name.
**/
/*
* 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);
/* Return a pointer to the system property named name, if it
** exists, or NULL if there is no such property. Use
** __system_property_read() to obtain the string value from
** the returned prop_info pointer.
**
** It is safe to cache the prop_info pointer to avoid future
** lookups. These returned pointers will remain valid for
** the lifetime of the system.
*/
const prop_info *__system_property_find(const char *name);
/*
* 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.
*
* 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);
/* Read the value of a system property. Returns the length
** of the value. Copies the value and \0 terminator into
** the provided value pointer. Total length (including
** terminator) will be no greater that PROP_VALUE_MAX for
** __system_property_read.
**
** If name is nonzero, up to PROP_NAME_MAX bytes will be
** copied into the provided name pointer. The name will
** be \0 terminated.
*/
int __system_property_read(const prop_info *pi, char *name, char *value);
/*
* 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 (*)(void* cookie, const char *name, const char *value),
void* cookie) __INTRODUCED_IN_FUTURE;
void (*callback)(void* cookie, const char *name, const char *value, uint32_t serial),
void* cookie) __INTRODUCED_IN_FUTURE;
/* Return a prop_info for the nth system property, or NULL if
** there is no nth property. Use __system_property_read() to
** read the value of this property.
**
** Please do not call this method. It only exists to provide
** backwards compatibility to NDK apps. Its implementation
** is inefficient and order of results may change from call
** to call.
*/
const prop_info *__system_property_find_nth(unsigned n)
__REMOVED_IN(26);
/* Pass a prop_info for each system property to the provided
** callback. Use __system_property_read() to read the value
** of this property.
**
** This method is for inspecting and debugging the property
** system. Please use __system_property_find() instead.
**
** Order of results may change from call to call. This is
** not a bug.
*/
/*
* Passes a `prop_info` for each system property to the provided
* callback. Use __system_property_read_callback() 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)
__INTRODUCED_IN(19);
/* 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);
__END_DECLS
#endif

1
libc/libc.arm.map
View file

@ -1266,6 +1266,7 @@ LIBC_N { # introduced-arm64=24 introduced-mips=24 introduced-mips64=24 introduce
LIBC_O {
global:
__system_property_read_callback; # future
__system_property_wait; # future
bsd_signal; # arm x86 mips versioned=26
catclose; # future
catgets; # future

1
libc/libc.arm64.map
View file

@ -1189,6 +1189,7 @@ LIBC_N { # introduced-arm64=24 introduced-mips=24 introduced-mips64=24 introduce
LIBC_O {
global:
__system_property_read_callback; # future
__system_property_wait; # future
catclose; # future
catgets; # future
catopen; # future

1
libc/libc.map.txt
View file

@ -1291,6 +1291,7 @@ LIBC_N { # introduced-arm64=24 introduced-mips=24 introduced-mips64=24 introduce
LIBC_O {
global:
__system_property_read_callback; # future
__system_property_wait; # future
bsd_signal; # arm x86 mips versioned=26
catclose; # future
catgets; # future

1
libc/libc.mips.map
View file

@ -1250,6 +1250,7 @@ LIBC_N { # introduced-arm64=24 introduced-mips=24 introduced-mips64=24 introduce
LIBC_O {
global:
__system_property_read_callback; # future
__system_property_wait; # future
bsd_signal; # arm x86 mips versioned=26
catclose; # future
catgets; # future

1
libc/libc.mips64.map
View file

@ -1189,6 +1189,7 @@ LIBC_N { # introduced-arm64=24 introduced-mips=24 introduced-mips64=24 introduce
LIBC_O {
global:
__system_property_read_callback; # future
__system_property_wait; # future
catclose; # future
catgets; # future
catopen; # future

1
libc/libc.x86.map
View file

@ -1248,6 +1248,7 @@ LIBC_N { # introduced-arm64=24 introduced-mips=24 introduced-mips64=24 introduce
LIBC_O {
global:
__system_property_read_callback; # future
__system_property_wait; # future
bsd_signal; # arm x86 mips versioned=26
catclose; # future
catgets; # future

1
libc/libc.x86_64.map
View file

@ -1189,6 +1189,7 @@ LIBC_N { # introduced-arm64=24 introduced-mips=24 introduced-mips64=24 introduce
LIBC_O {
global:
__system_property_read_callback; # future
__system_property_wait; # future
catclose; # future
catgets; # future
catopen; # future

94
tests/system_properties_test.cpp
View file

@ -20,7 +20,9 @@
#include <errno.h>
#include <sys/wait.h>
#include <unistd.h>
#include <string>
#include <thread>
#if defined(__BIONIC__)
@ -111,13 +113,11 @@ static void* PropertyWaitHelperFn(void* arg) {
#endif // __BIONIC__
TEST(properties, add) {
TEST(properties, __system_property_add) {
#if defined(__BIONIC__)
LocalPropertyTestState pa;
ASSERT_TRUE(pa.valid);
char propvalue[PROP_VALUE_MAX];
ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
ASSERT_EQ(0, __system_property_add("other_property", 14, "value2", 6));
ASSERT_EQ(0, __system_property_add("property_other", 14, "value3", 6));
@ -132,6 +132,7 @@ TEST(properties, add) {
name[sizeof(name)-1] = '\0';
ASSERT_EQ(0, __system_property_add(name, strlen(name), "value", 5));
char propvalue[PROP_VALUE_MAX];
ASSERT_EQ(6, __system_property_get("property", propvalue));
ASSERT_STREQ(propvalue, "value1");
@ -148,30 +149,28 @@ TEST(properties, add) {
#endif // __BIONIC__
}
TEST(properties, update) {
TEST(properties, __system_property_update) {
#if defined(__BIONIC__)
LocalPropertyTestState pa;
ASSERT_TRUE(pa.valid);
char propvalue[PROP_VALUE_MAX];
prop_info *pi;
ASSERT_EQ(0, __system_property_add("property", 8, "oldvalue1", 9));
ASSERT_EQ(0, __system_property_add("other_property", 14, "value2", 6));
ASSERT_EQ(0, __system_property_add("property_other", 14, "value3", 6));
pi = (prop_info *)__system_property_find("property");
ASSERT_NE((prop_info *)NULL, pi);
__system_property_update(pi, "value4", 6);
const prop_info* pi = __system_property_find("property");
ASSERT_TRUE(pi != nullptr);
__system_property_update(const_cast<prop_info*>(pi), "value4", 6);
pi = (prop_info *)__system_property_find("other_property");
ASSERT_NE((prop_info *)NULL, pi);
__system_property_update(pi, "newvalue5", 9);
pi = __system_property_find("other_property");
ASSERT_TRUE(pi != nullptr);
__system_property_update(const_cast<prop_info*>(pi), "newvalue5", 9);
pi = (prop_info *)__system_property_find("property_other");
ASSERT_NE((prop_info *)NULL, pi);
__system_property_update(pi, "value6", 6);
pi = __system_property_find("property_other");
ASSERT_TRUE(pi != nullptr);
__system_property_update(const_cast<prop_info*>(pi), "value6", 6);
char propvalue[PROP_VALUE_MAX];
ASSERT_EQ(6, __system_property_get("property", propvalue));
ASSERT_STREQ(propvalue, "value4");
@ -230,16 +229,16 @@ TEST(properties, fill) {
#endif // __BIONIC__
}
TEST(properties, foreach) {
TEST(properties, __system_property_foreach) {
#if defined(__BIONIC__)
LocalPropertyTestState pa;
ASSERT_TRUE(pa.valid);
size_t count = 0;
ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
ASSERT_EQ(0, __system_property_add("other_property", 14, "value2", 6));
ASSERT_EQ(0, __system_property_add("property_other", 14, "value3", 6));
size_t count = 0;
ASSERT_EQ(0, __system_property_foreach(foreach_test_callback, &count));
ASSERT_EQ(3U, count);
#else // __BIONIC__
@ -247,7 +246,7 @@ TEST(properties, foreach) {
#endif // __BIONIC__
}
TEST(properties, find_nth) {
TEST(properties, __system_property_find_nth) {
#if defined(__BIONIC__)
LocalPropertyTestState pa;
ASSERT_TRUE(pa.valid);
@ -342,47 +341,74 @@ TEST(properties, errors) {
#endif // __BIONIC__
}
TEST(properties, serial) {
TEST(properties, __system_property_serial) {
#if defined(__BIONIC__)
LocalPropertyTestState pa;
ASSERT_TRUE(pa.valid);
const prop_info *pi;
unsigned int serial;
ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
ASSERT_NE((const prop_info *)NULL, pi = __system_property_find("property"));
serial = __system_property_serial(pi);
ASSERT_EQ(0, __system_property_update((prop_info *)pi, "value2", 6));
const prop_info* pi = __system_property_find("property");
ASSERT_TRUE(pi != nullptr);
unsigned serial = __system_property_serial(pi);
ASSERT_EQ(0, __system_property_update(const_cast<prop_info*>(pi), "value2", 6));
ASSERT_NE(serial, __system_property_serial(pi));
#else // __BIONIC__
GTEST_LOG_(INFO) << "This test does nothing.\n";
#endif // __BIONIC__
}
TEST(properties, wait) {
TEST(properties, __system_property_wait_any) {
#if defined(__BIONIC__)
LocalPropertyTestState pa;
ASSERT_TRUE(pa.valid);
unsigned int serial;
prop_info *pi;
pthread_t t;
int flag = 0;
ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
serial = __system_property_wait_any(0);
unsigned serial = __system_property_wait_any(0);
pi = const_cast<prop_info*>(__system_property_find("property"));
prop_info* pi = const_cast<prop_info*>(__system_property_find("property"));
ASSERT_TRUE(pi != nullptr);
__system_property_update(pi, "value2", 6);
serial = __system_property_wait_any(serial);
int flag = 0;
pthread_t t;
ASSERT_EQ(0, pthread_create(&t, nullptr, PropertyWaitHelperFn, &flag));
ASSERT_EQ(flag, 0);
serial = __system_property_wait_any(serial);
ASSERT_EQ(flag, 1);
void* result;
ASSERT_EQ(0, pthread_join(t, &result));
ASSERT_EQ(0, pthread_join(t, nullptr));
#else // __BIONIC__
GTEST_LOG_(INFO) << "This test does nothing.\n";
#endif // __BIONIC__
}
TEST(properties, __system_property_wait) {
#if defined(__BIONIC__)
LocalPropertyTestState pa;
ASSERT_TRUE(pa.valid);
ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
prop_info* pi = const_cast<prop_info*>(__system_property_find("property"));
ASSERT_TRUE(pi != nullptr);
unsigned serial = __system_property_serial(pi);
std::thread thread([]() {
prop_info* pi = const_cast<prop_info*>(__system_property_find("property"));
ASSERT_TRUE(pi != nullptr);
__system_property_update(pi, "value2", 6);
});
__system_property_wait(pi, serial);
char value[PROP_VALUE_MAX];
ASSERT_EQ(6, __system_property_get("property", value));
ASSERT_STREQ("value2", value);
thread.join();
#else // __BIONIC__
GTEST_LOG_(INFO) << "This test does nothing.\n";
#endif // __BIONIC__

18
tests/system_properties_test2.cpp
View file

@ -90,20 +90,22 @@ TEST(properties, smoke) {
ASSERT_TRUE(pi != nullptr);
std::string expected_name = property_name;
__system_property_read_callback(pi, [](void* cookie, const char *name, const char *value) {
const std::string* expected_name = static_cast<const std::string*>(cookie);
ASSERT_EQ(*expected_name, name);
ASSERT_STREQ("value1-1", value);
__system_property_read_callback(pi,
[](void* cookie, const char* name, const char* value, unsigned /*serial*/) {
const std::string* expected_name = static_cast<const std::string*>(cookie);
ASSERT_EQ(*expected_name, name);
ASSERT_STREQ("value1-1", value);
}, &expected_name);
pi = __system_property_find(long_property_name.c_str());
ASSERT_TRUE(pi != nullptr);
expected_name = long_property_name;
__system_property_read_callback(pi, [](void* cookie, const char *name, const char *value) {
const std::string* expected_name = static_cast<const std::string*>(cookie);
ASSERT_EQ(*expected_name, name);
ASSERT_STREQ("value2", value);
__system_property_read_callback(pi,
[](void* cookie, const char* name, const char* value, unsigned /*serial*/) {
const std::string* expected_name = static_cast<const std::string*>(cookie);
ASSERT_EQ(*expected_name, name);
ASSERT_STREQ("value2", value);
}, &expected_name);
// Check that read() for long names still works but returns truncated version of the name