| /* |
| * Copyright (C) 2016 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| // IWYU pragma: private, include "chre_api/chre.h" |
| // IWYU pragma: friend chre/.*\.h |
| |
| #ifndef _CHRE_RE_H_ |
| #define _CHRE_RE_H_ |
| |
| /** |
| * @file |
| * Some of the core Runtime Environment utilities of the Context Hub |
| * Runtime Environment. |
| * |
| * This includes functions for memory allocation, logging, and timers. |
| */ |
| |
| #include <stdarg.h> |
| #include <stdbool.h> |
| #include <stdint.h> |
| #include <stdlib.h> |
| |
| #include <chre/toolchain.h> |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /** |
| * The instance ID for the CHRE. |
| * |
| * This ID is used to identify events generated by the CHRE (as |
| * opposed to events generated by another nanoapp). |
| */ |
| #define CHRE_INSTANCE_ID UINT32_C(0) |
| |
| /** |
| * A timer ID representing an invalid timer. |
| * |
| * This valid is returned by chreTimerSet() if a timer cannot be |
| * started. |
| */ |
| #define CHRE_TIMER_INVALID UINT32_C(-1) |
| |
| |
| /** |
| * The maximum size, in characters including null terminator, guaranteed for |
| * logging debug data with one call of chreDebugDumpLog() without getting |
| * truncated. |
| * |
| * @see chreDebugDumpLog |
| * @since v1.4 |
| */ |
| #define CHRE_DEBUG_DUMP_MINIMUM_MAX_SIZE 1000 |
| |
| /** |
| * Logging levels used to indicate severity level of logging messages. |
| * |
| * CHRE_LOG_ERROR: Something fatal has happened, i.e. something that will have |
| * user-visible consequences and won't be recoverable without explicitly |
| * deleting some data, uninstalling applications, wiping the data |
| * partitions or reflashing the entire phone (or worse). |
| * CHRE_LOG_WARN: Something that will have user-visible consequences but is |
| * likely to be recoverable without data loss by performing some explicit |
| * action, ranging from waiting or restarting an app all the way to |
| * re-downloading a new version of an application or rebooting the device. |
| * CHRE_LOG_INFO: Something interesting to most people happened, i.e. when a |
| * situation is detected that is likely to have widespread impact, though |
| * isn't necessarily an error. |
| * CHRE_LOG_DEBUG: Used to further note what is happening on the device that |
| * could be relevant to investigate and debug unexpected behaviors. You |
| * should log only what is needed to gather enough information about what |
| * is going on about your component. |
| * |
| * There is currently no API to turn on/off logging by level, but we anticipate |
| * adding such in future releases. |
| * |
| * @see chreLog |
| */ |
| enum chreLogLevel { |
| CHRE_LOG_ERROR, |
| CHRE_LOG_WARN, |
| CHRE_LOG_INFO, |
| CHRE_LOG_DEBUG |
| }; |
| |
| |
| /** |
| * Get the application ID. |
| * |
| * The application ID is set by the loader of the nanoapp. This is not |
| * assured to be unique among all nanoapps running in the system. |
| * |
| * @return The application ID. |
| */ |
| uint64_t chreGetAppId(void); |
| |
| /** |
| * Get the instance ID. |
| * |
| * The instance ID is the CHRE handle to this nanoapp. This is assured |
| * to be unique among all nanoapps running in the system, and to be |
| * different from the CHRE_INSTANCE_ID. This is the ID used to communicate |
| * between nanoapps. |
| * |
| * @return The instance ID |
| */ |
| uint32_t chreGetInstanceId(void); |
| |
| /** |
| * A method for logging information about the system. |
| * |
| * The chreLog logging activity alone must not cause host wake-ups. For |
| * example, logs could be buffered in internal memory when the host is asleep, |
| * and delivered when appropriate (e.g. the host wakes up). If done this way, |
| * the internal buffer is recommended to be large enough (at least a few KB), so |
| * that multiple messages can be buffered. When these logs are sent to the host, |
| * they are strongly recommended to be made visible under the tag 'CHRE' in |
| * logcat - a future version of the CHRE API may make this a hard requirement. |
| * |
| * A log entry can have a variety of levels (@see LogLevel). This function |
| * allows a variable number of arguments, in a printf-style format. |
| * |
| * A nanoapp needs to be able to rely upon consistent printf format |
| * recognition across any platform, and thus we establish formats which |
| * are required to be handled by every CHRE implementation. Some of the |
| * integral formats may seem obscure, but this API heavily uses types like |
| * uint32_t and uint16_t. The platform independent macros for those printf |
| * formats, like PRId32 or PRIx16, end up using some of these "obscure" |
| * formats on some platforms, and thus are required. |
| * |
| * For the initial N release, our emphasis is on correctly getting information |
| * into the log, and minimizing the requirements for CHRE implementations |
| * beyond that. We're not as concerned about how the information is visually |
| * displayed. As a result, there are a number of format sub-specifiers which |
| * are "OPTIONAL" for the N implementation. "OPTIONAL" in this context means |
| * that a CHRE implementation is allowed to essentially ignore the specifier, |
| * but it must understand the specifier enough in order to properly skip it. |
| * |
| * For a nanoapp author, an OPTIONAL format means you might not get exactly |
| * what you want on every CHRE implementation, but you will always get |
| * something valid. |
| * |
| * To be clearer, here's an example with the OPTIONAL 0-padding for integers |
| * for different hypothetical CHRE implementations. |
| * Compliant, chose to implement OPTIONAL format: |
| * chreLog(level, "%04x", 20) ==> "0014" |
| * Compliant, chose not to implement OPTIONAL format: |
| * chreLog(level, "%04x", 20) ==> "14" |
| * Non-compliant, discarded format because the '0' was assumed to be incorrect: |
| * chreLog(level, "%04x", 20) ==> "" |
| * |
| * Note that some of the OPTIONAL specifiers will probably become |
| * required in future APIs. |
| * |
| * We also have NOT_SUPPORTED specifiers. Nanoapp authors should not use any |
| * NOT_SUPPORTED specifiers, as unexpected things could happen on any given |
| * CHRE implementation. A CHRE implementation is allowed to support this |
| * (for example, when using shared code which already supports this), but |
| * nanoapp authors need to avoid these. |
| * |
| * Unless specifically noted as OPTIONAL or NOT_SUPPORTED, format |
| * (sub-)specifiers listed below are required. |
| * |
| * OPTIONAL format sub-specifiers: |
| * - '-' (left-justify within the given field width) |
| * - '+' (precede the result with a '+' sign if it is positive) |
| * - ' ' (precede the result with a blank space if no sign is going to be |
| * output) |
| * - '#' (For 'o', 'x' or 'X', precede output with "0", "0x" or "0X", |
| * respectively. For floating point, unconditionally output a decimal |
| * point.) |
| * - '0' (left pad the number with zeroes instead of spaces when <width> |
| * needs padding) |
| * - <width> (A number representing the minimum number of characters to be |
| * output, left-padding with blank spaces if needed to meet the |
| * minimum) |
| * - '.'<precision> (A number which has different meaning depending on context.) |
| * - Integer context: Minimum number of digits to output, padding with |
| * leading zeros if needed to meet the minimum. |
| * - 'f' context: Number of digits to output after the decimal |
| * point (to the right of it). |
| * - 's' context: Maximum number of characters to output. |
| * |
| * Integral format specifiers: |
| * - 'd' (signed) |
| * - 'u' (unsigned) |
| * - 'o' (octal) |
| * - 'x' (hexadecimal, lower case) |
| * - 'X' (hexadecimal, upper case) |
| * |
| * Integral format sub-specifiers (as prefixes to an above integral format): |
| * - 'hh' (char) |
| * - 'h' (short) |
| * - 'l' (long) |
| * - 'll' (long long) |
| * - 'z' (size_t) |
| * - 't' (ptrdiff_t) |
| * |
| * Other format specifiers: |
| * - 'f' (floating point) |
| * - 'c' (character) |
| * - 's' (character string, terminated by '\0') |
| * - 'p' (pointer) |
| * - '%' (escaping the percent sign (i.e. "%%" becomes "%")) |
| * |
| * NOT_SUPPORTED specifiers: |
| * - 'n' (output nothing, but fill in a given pointer with the number |
| * of characters written so far) |
| * - '*' (indicates that the width/precision value comes from one of the |
| * arguments to the function) |
| * - 'e', 'E' (scientific notation output) |
| * - 'g', 'G' (Shortest floating point representation) |
| * |
| * @param level The severity level for this message. |
| * @param formatStr Either the entirety of the message, or a printf-style |
| * format string of the format documented above. |
| * @param ... A variable number of arguments necessary for the given |
| * 'formatStr' (there may be no additional arguments for some 'formatStr's). |
| */ |
| CHRE_PRINTF_ATTR(2, 3) |
| void chreLog(enum chreLogLevel level, const char *formatStr, ...); |
| |
| /** |
| * Get the system time. |
| * |
| * This returns a time in nanoseconds in reference to some arbitrary |
| * time in the past. This method is only useful for determining timing |
| * between events on the system, and is not useful for determining |
| * any sort of absolute time. |
| * |
| * This value must always increase (and must never roll over). This |
| * value has no meaning across CHRE reboots. |
| * |
| * @return The system time, in nanoseconds. |
| */ |
| uint64_t chreGetTime(void); |
| |
| /** |
| * Retrieves CHRE's current estimated offset between the local CHRE clock |
| * exposed in chreGetTime(), and the host-side clock exposed in the Android API |
| * SystemClock.elapsedRealtimeNanos(). This offset is formed as host time minus |
| * CHRE time, so that it can be added to the value returned by chreGetTime() to |
| * determine the current estimate of the host time. |
| * |
| * A call to this function must not require waking up the host and should return |
| * quickly. |
| * |
| * This function must always return a valid value from the earliest point that |
| * it can be called by a nanoapp. In other words, it is not valid to return |
| * some fixed/invalid value while waiting for the initial offset estimate to be |
| * determined - this initial offset must be ready before nanoapps are started. |
| * |
| * @return An estimate of the offset between CHRE's time returned in |
| * chreGetTime() and the time on the host given in the Android API |
| * SystemClock.elapsedRealtimeNanos(), accurate to within +/- 10 |
| * milliseconds, such that adding this offset to chreGetTime() produces the |
| * estimated current time on the host. This value may change over time to |
| * account for drift, etc., so multiple calls to this API may produce |
| * different results. |
| * |
| * @since v1.1 |
| */ |
| int64_t chreGetEstimatedHostTimeOffset(void); |
| |
| /** |
| * Convenience function to retrieve CHRE's estimate of the current time on the |
| * host, corresponding to the Android API SystemClock.elapsedRealtimeNanos(). |
| * |
| * @return An estimate of the current time on the host, accurate to within |
| * +/- 10 milliseconds. This estimate is *not* guaranteed to be |
| * monotonically increasing, and may move backwards as a result of receiving |
| * new information from the host. |
| * |
| * @since v1.1 |
| */ |
| static inline uint64_t chreGetEstimatedHostTime(void) { |
| int64_t offset = chreGetEstimatedHostTimeOffset(); |
| uint64_t time = chreGetTime(); |
| |
| // Just casting time to int64_t and adding the (potentially negative) offset |
| // should be OK under most conditions, but this way avoids issues if |
| // time >= 2^63, which is technically allowed since we don't specify a start |
| // value for chreGetTime(), though one would assume 0 is roughly boot time. |
| if (offset >= 0) { |
| time += (uint64_t) offset; |
| } else { |
| // Assuming chreGetEstimatedHostTimeOffset() is implemented properly, |
| // this will never underflow, because offset = hostTime - chreTime, |
| // and both times are monotonically increasing (e.g. when determining |
| // the offset, if hostTime is 0 and chreTime is 100 we'll have |
| // offset = -100, but chreGetTime() will always return >= 100 after that |
| // point). |
| time -= (uint64_t) (offset * -1); |
| } |
| |
| return time; |
| } |
| |
| /** |
| * Set a timer. |
| * |
| * When the timer fires, nanoappHandleEvent will be invoked with |
| * CHRE_EVENT_TIMER and with the given 'cookie'. |
| * |
| * A CHRE implementation is required to provide at least 32 |
| * timers. However, there's no assurance there will be any available |
| * for any given nanoapp (if it's loaded late, etc). |
| * |
| * @param duration Time, in nanoseconds, before the timer fires. |
| * @param cookie Argument that will be sent to nanoappHandleEvent upon the |
| * timer firing. This is allowed to be NULL and does not need to be |
| * a valid pointer (assuming the nanoappHandleEvent code is expecting such). |
| * @param oneShot If true, the timer will just fire once. If false, the |
| * timer will continue to refire every 'duration', until this timer is |
| * canceled (@see chreTimerCancel). |
| * |
| * @return The timer ID. If the system is unable to set a timer |
| * (no more available timers, etc.) then CHRE_TIMER_INVALID will |
| * be returned. |
| * |
| * @see nanoappHandleEvent |
| */ |
| uint32_t chreTimerSet(uint64_t duration, const void *cookie, bool oneShot); |
| |
| /** |
| * Cancel a timer. |
| * |
| * After this method returns, the CHRE assures there will be no more |
| * events sent from this timer, and any enqueued events from this timer |
| * will need to be evicted from the queue by the CHRE. |
| * |
| * @param timerId A timer ID obtained by this nanoapp via chreTimerSet(). |
| * @return true if the timer was cancelled, false otherwise. We may |
| * fail to cancel the timer if it's a one shot which (just) fired, |
| * or if the given timer ID is not owned by the calling app. |
| */ |
| bool chreTimerCancel(uint32_t timerId); |
| |
| /** |
| * Terminate this nanoapp. |
| * |
| * This takes effect immediately. |
| * |
| * The CHRE will no longer execute this nanoapp. The CHRE will not invoke |
| * nanoappEnd(), nor will it call any memory free callbacks in the nanoapp. |
| * |
| * The CHRE will unload/evict this nanoapp's code. |
| * |
| * @param abortCode A value indicating the reason for aborting. (Note that |
| * in this version of the API, there is no way for anyone to access this |
| * code, but future APIs may expose it.) |
| * @return Never. This method does not return, as the CHRE stops nanoapp |
| * execution immediately. |
| */ |
| void chreAbort(uint32_t abortCode) CHRE_NO_RETURN; |
| |
| /** |
| * Allocate a given number of bytes from the system heap. |
| * |
| * The nanoapp is required to free this memory via chreHeapFree() prior to |
| * the nanoapp ending. |
| * |
| * While the CHRE implementation is required to free up heap resources of |
| * a nanoapp when unloading it, future requirements and tests focused on |
| * nanoapps themselves may check for memory leaks, and will require nanoapps |
| * to properly manage their heap resources. |
| * |
| * @param bytes The number of bytes requested. |
| * @return A pointer to 'bytes' contiguous bytes of heap memory, or NULL |
| * if the allocation could not be performed. This pointer must be suitably |
| * aligned for any kind of variable. |
| * |
| * @see chreHeapFree. |
| */ |
| void *chreHeapAlloc(uint32_t bytes); |
| |
| /** |
| * Free a heap allocation. |
| * |
| * This allocation must be from a value returned from a chreHeapAlloc() call |
| * made by this nanoapp. In other words, it is illegal to free memory |
| * allocated by another nanoapp (or the CHRE). |
| * |
| * @param ptr 'ptr' is required to be a value returned from chreHeapAlloc(). |
| * Note that since chreHeapAlloc can return NULL, CHRE |
| * implementations must safely handle 'ptr' being NULL. |
| * |
| * @see chreHeapAlloc. |
| */ |
| void chreHeapFree(void *ptr); |
| |
| /** |
| * Logs the nanoapp's debug data into debug dumps. |
| * |
| * A debug dump is a string representation of information that can be used to |
| * diagnose and debug issues. While chreLog() is useful for logging events as |
| * they happen, the debug dump is a complementary function typically used to |
| * output a snapshot of a nanoapp's state, history, vital statistics, etc. The |
| * CHRE framework is required to pass this information to the debug method in |
| * the Context Hub HAL, where it can be captured in Android bugreports, etc. |
| * |
| * This function must only be called while handling CHRE_DEBUG_DUMP_EVENT, |
| * otherwise it will have no effect. A nanoapp can call this function multiple |
| * times while handling the event. If the resulting formatted string from a |
| * single call to this function is longer than CHRE_DEBUG_DUMP_MINIMUM_MAX_SIZE |
| * characters, it may get truncated. |
| * |
| * @param formatStr A printf-style format string of the format documented in |
| * chreLog(). |
| * @param ... A variable number of arguments necessary for the given 'formatStr' |
| * (there may be no additional arguments for some 'formatStr's). |
| * |
| * @see chreConfigureDebugDumpEvent |
| * @see chreLog |
| * |
| * @since v1.4 |
| */ |
| CHRE_PRINTF_ATTR(1, 2) |
| void chreDebugDumpLog(const char *formatStr, ...); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* _CHRE_RE_H_ */ |
| |