/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 *

 */

// os defines the interface to operating system; this includes traditional

// OS services (time, I/O) as well as other functionality with system-

// dependent code.

typedef void (*dll_func)(...);

class Thread;

class JavaThread;

class Event;

class DLL;

class FileHandle;

template<class E> class GrowableArray;

// %%%%% Moved ThreadState, START_FN, OSThread to new osThread.hpp. -- Rose

// Platform-independent error return values from OS functions

enum OSReturn {

  OS_OK         =  0,        // Operation was successful

  OS_ERR        = -1,        // Operation failed

  OS_INTRPT     = -2,        // Operation was interrupted

  OS_TIMEOUT    = -3,        // Operation timed out

  OS_NOMEM      = -5,        // Operation failed for lack of memory

  OS_NORESOURCE = -6         // Operation failed for lack of nonmemory resource

};

enum ThreadPriority {        // JLS 20.20.1-3

  NoPriority       = -1,     // Initial non-priority value

  MinPriority      =  1,     // Minimum priority

  NormPriority     =  5,     // Normal (non-daemon) priority

  NearMaxPriority  =  9,     // High priority, used for VMThread

  MaxPriority      = 10      // Highest priority, used for WatcherThread

                             // ensures that VMThread doesn't starve profiler

};

// Typedef for structured exception handling support

typedef void (*java_call_t)(JavaValue* value, methodHandle* method, JavaCallArguments* args, Thread* thread);

class os: AllStatic {

 public:

  enum { page_sizes_max = 9 }; // Size of _page_sizes array (8 plus a sentinel)

 private:

  static OSThread*          _starting_thread;

  static address            _polling_page;

  static volatile int32_t * _mem_serialize_page;

  static uintptr_t          _serialize_page_mask;

 public:

  static size_t             _page_sizes[page_sizes_max];

 private:

  static void init_page_sizes(size_t default_page_size) {

    _page_sizes[0] = default_page_size;

    _page_sizes[1] = 0; // sentinel

  }

 public:

  static void init(void);   // Called before command line parsing

  static jint init_2(void); // Called after command line parsing

  // File names are case-insensitive on windows only

  // Override me as needed

  static int    file_name_strcmp(const char* s1, const char* s2);

  static bool getenv(const char* name, char* buffer, int len);

  static bool have_special_privileges();

  static jlong  javaTimeMillis();

  static jlong  javaTimeNanos();

  static void   javaTimeNanos_info(jvmtiTimerInfo *info_ptr);

  static void   run_periodic_checks();

  // Returns the elapsed time in seconds since the vm started.

  static double elapsedTime();

  // Returns real time in seconds since an arbitrary point

  // in the past.

  static bool getTimesSecs(double* process_real_time,

                           double* process_user_time,

                           double* process_system_time);

  // Interface to the performance counter

  static jlong elapsed_counter();

  static jlong elapsed_frequency();

  // The "virtual time" of a thread is the amount of time a thread has

  // actually run.  The first function indicates whether the OS supports

  // this functionality for the current thread, and if so:

  //   * the second enables vtime tracking (if that is required).

  //   * the third tells whether vtime is enabled.

  //   * the fourth returns the elapsed virtual time for the current

  //     thread.

  static bool supports_vtime();

  static bool enable_vtime();

  static bool vtime_enabled();

  static double elapsedVTime();

  // Return current local time in a string (YYYY-MM-DD HH:MM:SS).

  // It is MT safe, but not async-safe, as reading time zone

  // information may require a lock on some platforms.

  static char*      local_time_string(char *buf, size_t buflen);

  static struct tm* localtime_pd     (const time_t* clock, struct tm*  res);

  // Fill in buffer with current local time as an ISO-8601 string.

  // E.g., YYYY-MM-DDThh:mm:ss.mmm+zzzz.

  // Returns buffer, or NULL if it failed.

  static char* iso8601_time(char* buffer, size_t buffer_length);

  // Interface for detecting multiprocessor system

  static inline bool is_MP() {

    assert(_processor_count > 0, "invalid processor count");

    return _processor_count > 1;

  }

  static julong available_memory();

  static julong physical_memory();

  static julong allocatable_physical_memory(julong size);

  static bool is_server_class_machine();

  // number of CPUs

  static int processor_count() {

    return _processor_count;

  }

  static void set_processor_count(int count) { _processor_count = count; }

  // Returns the number of CPUs this process is currently allowed to run on.

  // Note that on some OSes this can change dynamically.

  static int active_processor_count();

  // Bind processes to processors.

  //     This is a two step procedure:

  //     first you generate a distribution of processes to processors,

  //     then you bind processes according to that distribution.

  // Compute a distribution for number of processes to processors.

  //    Stores the processor id's into the distribution array argument.

  //    Returns true if it worked, false if it didn't.

  static bool distribute_processes(uint length, uint* distribution);

  // Binds the current process to a processor.

  //    Returns true if it worked, false if it didn't.

  static bool bind_to_processor(uint processor_id);

  // Interface for stack banging (predetect possible stack overflow for

  // exception processing)  There are guard pages, and above that shadow

  // pages for stack overflow checking.

  static bool uses_stack_guard_pages();

  static bool allocate_stack_guard_pages();

  static void bang_stack_shadow_pages();

  static bool stack_shadow_pages_available(Thread *thread, methodHandle method);

  // OS interface to Virtual Memory

  // Return the default page size.

  static int    vm_page_size();

  // Return the page size to use for a region of memory.  The min_pages argument

  // is a hint intended to limit fragmentation; it says the returned page size

  // should be <= region_max_size / min_pages.  Because min_pages is a hint,

  // this routine may return a size larger than region_max_size / min_pages.

  //

  // The current implementation ignores min_pages if a larger page size is an

  // exact multiple of both region_min_size and region_max_size.  This allows

  // larger pages to be used when doing so would not cause fragmentation; in

  // particular, a single page can be used when region_min_size ==

  // region_max_size == a supported page size.

  static size_t page_size_for_region(size_t region_min_size,

                                     size_t region_max_size,

                                     uint min_pages);

  // Method for tracing page sizes returned by the above method; enabled by

  // TracePageSizes.  The region_{min,max}_size parameters should be the values

  // passed to page_size_for_region() and page_size should be the result of that

  // call.  The (optional) base and size parameters should come from the

  // ReservedSpace base() and size() methods.

  static void trace_page_sizes(const char* str, const size_t region_min_size,

                               const size_t region_max_size,

                               const size_t page_size,

                               const char* base = NULL,

                               const size_t size = 0) PRODUCT_RETURN;

  static int    vm_allocation_granularity();

  static char*  reserve_memory(size_t bytes, char* addr = 0,

                               size_t alignment_hint = 0);

  static char*  attempt_reserve_memory_at(size_t bytes, char* addr);

  static void   split_reserved_memory(char *base, size_t size,

                                      size_t split, bool realloc);

  static bool   commit_memory(char* addr, size_t bytes,

                              bool executable = false);

  static bool   commit_memory(char* addr, size_t size, size_t alignment_hint,

                              bool executable = false);

  static bool   uncommit_memory(char* addr, size_t bytes);

  static bool   release_memory(char* addr, size_t bytes);

  enum ProtType { MEM_PROT_NONE, MEM_PROT_READ, MEM_PROT_RW, MEM_PROT_RWX };

  static bool   protect_memory(char* addr, size_t bytes, ProtType prot,

                               bool is_committed = true);

  static bool   guard_memory(char* addr, size_t bytes);

  static bool   unguard_memory(char* addr, size_t bytes);

  static bool   create_stack_guard_pages(char* addr, size_t bytes);

  static bool   remove_stack_guard_pages(char* addr, size_t bytes);

  static char*  map_memory(int fd, const char* file_name, size_t file_offset,

                           char *addr, size_t bytes, bool read_only = false,

                           bool allow_exec = false);

  static char*  remap_memory(int fd, const char* file_name, size_t file_offset,

                             char *addr, size_t bytes, bool read_only,

                             bool allow_exec);

  static bool   unmap_memory(char *addr, size_t bytes);

  static void   free_memory(char *addr, size_t bytes);

  static void   realign_memory(char *addr, size_t bytes, size_t alignment_hint);

  // NUMA-specific interface

  static bool   numa_has_static_binding();

  static bool   numa_has_group_homing();

  static void   numa_make_local(char *addr, size_t bytes, int lgrp_hint);

  static void   numa_make_global(char *addr, size_t bytes);

  static size_t numa_get_groups_num();

  static size_t numa_get_leaf_groups(int *ids, size_t size);

  static bool   numa_topology_changed();

  static int    numa_get_group_id();

  // Page manipulation

  struct page_info {

    size_t size;

    int lgrp_id;

  };

  static bool   get_page_info(char *start, page_info* info);

  static char*  scan_pages(char *start, char* end, page_info* page_expected, page_info* page_found);

  static char*  non_memory_address_word();

  // reserve, commit and pin the entire memory region

  static char*  reserve_memory_special(size_t size, char* addr = NULL,

                bool executable = false);

  static bool   release_memory_special(char* addr, size_t bytes);

  static bool   large_page_init();

  static size_t large_page_size();

  static bool   can_commit_large_page_memory();

  static bool   can_execute_large_page_memory();

  // OS interface to polling page

  static address get_polling_page()             { return _polling_page; }

  static void    set_polling_page(address page) { _polling_page = page; }

  static bool    is_poll_address(address addr)  { return addr >= _polling_page && addr < (_polling_page + os::vm_page_size()); }

  static void    make_polling_page_unreadable();

  static void    make_polling_page_readable();

  // Routines used to serialize the thread state without using membars

  static void    serialize_thread_states();

  // Since we write to the serialize page from every thread, we

  // want stores to be on unique cache lines whenever possible

  // in order to minimize CPU cross talk.  We pre-compute the

  // amount to shift the thread* to make this offset unique to

  // each thread.

  static int     get_serialize_page_shift_count() {

    return SerializePageShiftCount;

  }

  static void     set_serialize_page_mask(uintptr_t mask) {

    _serialize_page_mask = mask;

  }

  static unsigned int  get_serialize_page_mask() {

    return _serialize_page_mask;

  }

  static void    set_memory_serialize_page(address page);

  static address get_memory_serialize_page() {

    return (address)_mem_serialize_page;

  }

  static inline void write_memory_serialize_page(JavaThread *thread) {

    uintptr_t page_offset = ((uintptr_t)thread >>

                            get_serialize_page_shift_count()) &

                            get_serialize_page_mask();

    *(volatile int32_t *)((uintptr_t)_mem_serialize_page+page_offset) = 1;

  }

  static bool    is_memory_serialize_page(JavaThread *thread, address addr) {

    if (UseMembar) return false;

    // Previously this function calculated the exact address of this

    // thread's serialize page, and checked if the faulting address

    // was equal.  However, some platforms mask off faulting addresses

    // to the page size, so now we just check that the address is

    // within the page.  This makes the thread argument unnecessary,

    // but we retain the NULL check to preserve existing behaviour.

    if (thread == NULL) return false;

    address page = (address) _mem_serialize_page;

    return addr >= page && addr < (page + os::vm_page_size());

  }

  static void block_on_serialize_page_trap();

  // threads

  enum ThreadType {

    vm_thread,

    cgc_thread,        // Concurrent GC thread

    pgc_thread,        // Parallel GC thread

    java_thread,

    compiler_thread,

    watcher_thread

  };

  static bool create_thread(Thread* thread,

                            ThreadType thr_type,

                            size_t stack_size = 0);

  static bool create_main_thread(JavaThread* thread);

  static bool create_attached_thread(JavaThread* thread);

  static void pd_start_thread(Thread* thread);

  static void start_thread(Thread* thread);

  static void initialize_thread();

  static void free_thread(OSThread* osthread);

  // thread id on Linux/64bit is 64bit, on Windows and Solaris, it's 32bit

  static intx current_thread_id();

  static int current_process_id();

  // hpi::read for calls from non native state

  // For performance, hpi::read is only callable from _thread_in_native

  static size_t read(int fd, void *buf, unsigned int nBytes);

  static int sleep(Thread* thread, jlong ms, bool interruptable);

  static int naked_sleep();

  static void infinite_sleep(); // never returns, use with CAUTION

  static void yield();        // Yields to all threads with same priority

  enum YieldResult {

    YIELD_SWITCHED = 1,         // caller descheduled, other ready threads exist & ran

    YIELD_NONEREADY = 0,        // No other runnable/ready threads.

                                // platform-specific yield return immediately

    YIELD_UNKNOWN = -1          // Unknown: platform doesn't support _SWITCHED or _NONEREADY

    // YIELD_SWITCHED and YIELD_NONREADY imply the platform supports a "strong"

    // yield that can be used in lieu of blocking.

  } ;

  static YieldResult NakedYield () ;

  static void yield_all(int attempts = 0); // Yields to all other threads including lower priority

  static void loop_breaker(int attempts);  // called from within tight loops to possibly influence time-sharing

  static OSReturn set_priority(Thread* thread, ThreadPriority priority);

  static OSReturn get_priority(const Thread* const thread, ThreadPriority& priority);

  static void interrupt(Thread* thread);

  static bool is_interrupted(Thread* thread, bool clear_interrupted);

  static int pd_self_suspend_thread(Thread* thread);

  static ExtendedPC fetch_frame_from_context(void* ucVoid, intptr_t** sp, intptr_t** fp);

  static frame      fetch_frame_from_context(void* ucVoid);

  static ExtendedPC get_thread_pc(Thread *thread);

  static void breakpoint();

  static address current_stack_pointer();

  static address current_stack_base();

  static size_t current_stack_size();

  static int message_box(const char* title, const char* message);

  static char* do_you_want_to_debug(const char* message);

  // run cmd in a separate process and return its exit code; or -1 on failures

  static int fork_and_exec(char *cmd);

  // Set file to send error reports.

  static void set_error_file(const char *logfile);

  // os::exit() is merged with vm_exit()

  // static void exit(int num);

  // Terminate the VM, but don't exit the process

  static void shutdown();

  // Terminate with an error.  Default is to generate a core file on platforms

  // that support such things.  This calls shutdown() and then aborts.

  static void abort(bool dump_core = true);

  // Die immediately, no exit hook, no abort hook, no cleanup.

  static void die();

  // Reading directories.

  static DIR*           opendir(const char* dirname);

  static int            readdir_buf_size(const char *path);

  static struct dirent* readdir(DIR* dirp, dirent* dbuf);

  static int            closedir(DIR* dirp);

  // Dynamic library extension

  static const char*    dll_file_extension();

  static const char*    get_temp_directory();

  static const char*    get_current_directory(char *buf, int buflen);

  // Builds a platform-specific full library path given a ld path and lib name

  static void           dll_build_name(char* buffer, size_t size,

                                       const char* pathname, const char* fname);

  // Symbol lookup, find nearest function name; basically it implements

  // dladdr() for all platforms. Name of the nearest function is copied

  // to buf. Distance from its base address is returned as offset.

  // If function name is not found, buf[0] is set to '\0' and offset is

  // set to -1.

  static bool dll_address_to_function_name(address addr, char* buf,

                                           int buflen, int* offset);

  // Locate DLL/DSO. On success, full path of the library is copied to

  // buf, and offset is set to be the distance between addr and the

  // library's base address. On failure, buf[0] is set to '\0' and

  // offset is set to -1.

  static bool dll_address_to_library_name(address addr, char* buf,

                                          int buflen, int* offset);

  // Find out whether the pc is in the static code for jvm.dll/libjvm.so.

  static bool address_is_in_vm(address addr);

  // Loads .dll/.so and

  // in case of error it checks if .dll/.so was built for the

  // same architecture as Hotspot is running on

  static void* dll_load(const char *name, char *ebuf, int ebuflen);

  // lookup symbol in a shared library

  static void* dll_lookup(void* handle, const char* name);

  // Print out system information; they are called by fatal error handler.

  // Output format may be different on different platforms.

  static void print_os_info(outputStream* st);

  static void print_cpu_info(outputStream* st);

  static void print_memory_info(outputStream* st);

  static void print_dll_info(outputStream* st);

  static void print_environment_variables(outputStream* st, const char** env_list, char* buffer, int len);

  static void print_context(outputStream* st, void* context);

  static void print_siginfo(outputStream* st, void* siginfo);

  static void print_signal_handlers(outputStream* st, char* buf, size_t buflen);

  static void print_date_and_time(outputStream* st);

  // The following two functions are used by fatal error handler to trace

  // native (C) frames. They are not part of frame.hpp/frame.cpp because

  // frame.hpp/cpp assume thread is JavaThread, and also because different

  // OS/compiler may have different convention or provide different API to

  // walk C frames.

  //

  // We don't attempt to become a debugger, so we only follow frames if that

  // does not require a lookup in the unwind table, which is part of the binary

  // file but may be unsafe to read after a fatal error. So on x86, we can

  // only walk stack if %ebp is used as frame pointer; on ia64, it's not

  // possible to walk C stack without having the unwind table.

  static bool is_first_C_frame(frame *fr);

  static frame get_sender_for_C_frame(frame *fr);

  // return current frame. pc() and sp() are set to NULL on failure.

  static frame      current_frame();

  static void print_hex_dump(outputStream* st, address start, address end, int unitsize);

  // returns a string to describe the exception/signal;

  // returns NULL if exception_code is not an OS exception/signal.

  static const char* exception_name(int exception_code, char* buf, size_t buflen);

  // Returns native Java library, loads if necessary

  static void*    native_java_library();

  // Fills in path to jvm.dll/libjvm.so (this info used to find hpi).

  static void     jvm_path(char *buf, jint buflen);

  // JNI names

  static void     print_jni_name_prefix_on(outputStream* st, int args_size);

  static void     print_jni_name_suffix_on(outputStream* st, int args_size);

  // File conventions

  static const char* file_separator();

  static const char* line_separator();

  static const char* path_separator();

  // Init os specific system properties values

  static void init_system_properties_values();

  // IO operations, non-JVM_ version.

  static int stat(const char* path, struct stat* sbuf);

  static bool dir_is_empty(const char* path);

  // IO operations on binary files

  static int create_binary_file(const char* path, bool rewrite_existing);

  static jlong current_file_offset(int fd);

  static jlong seek_to_file_offset(int fd, jlong offset);

  // Thread Local Storage

  static int   allocate_thread_local_storage();

  static void  thread_local_storage_at_put(int index, void* value);

  static void* thread_local_storage_at(int index);

  static void  free_thread_local_storage(int index);

  // General allocation (must be MT-safe)

  static void* malloc  (size_t size);

  static void* realloc (void *memblock, size_t size);

  static void  free    (void *memblock);

  static bool  check_heap(bool force = false);      // verify C heap integrity

  static char* strdup(const char *);  // Like strdup

#ifndef PRODUCT

  static int  num_mallocs;            // # of calls to malloc/realloc

  static size_t  alloc_bytes;         // # of bytes allocated

  static int  num_frees;              // # of calls to free

#endif