摘要
查询对象的相关信息。
声明
#include <zircon/syscalls.h>
zx_status_t zx_object_get_info(zx_handle_t handle,
uint32_t topic,
void* buffer,
size_t buffer_size,
size_t* actual,
size_t* avail);
说明
zx_object_get_info() 会请求有关所提供的句柄（或句柄所引用对象）的信息。topic 参数指示所需的特定信息。
buffer 是指向大小为 buffer_size 的缓冲区的指针，用于返回信息。
actual 是一个可选指针，用于返回写入缓冲区的记录数。
availability 是一个可选指针，用于返回可供读取的记录数。
如果缓冲区空间不够大，则播出信息将大于实际数据。
主题
ZX_INFO_HANDLE_VALID
handle 类型：Any
buffer 类型：n/a
如果 handle 有效，则返回 ZX_OK，否则返回 ZX_ERR_BAD_HANDLE。不返回任何记录，并且 buffer 可以为 NULL。
ZX_INFO_HANDLE_BASIC
handle 类型：Any
buffer 类型：zx_info_handle_basic_t[1]
typedef struct zx_info_handle_basic {
// The unique id assigned by kernel to the object referenced by the
// handle.
zx_koid_t koid;
// The immutable rights assigned to the handle. Two handles that
// have the same koid and the same rights are equivalent and
// interchangeable.
zx_rights_t rights;
// The object type: channel, event, socket, etc.
uint32_t type; // zx_obj_type_t;
// If the object referenced by the handle is related to another (such
// as the other end of a channel, or the parent of a job) then
// |related_koid| is the koid of that object, otherwise it is zero.
// This relationship is immutable: an object's |related_koid| does
// not change even if the related object no longer exists.
zx_koid_t related_koid;
} zx_info_handle_basic_t;
ZX_INFO_HANDLE_COUNT
handle 类型：Any
buffer 类型：zx_info_handle_count_t[1]
typedef struct zx_info_handle_count {
// The number of outstanding handles to a kernel object.
uint32_t handle_count;
} zx_info_handle_count_t;
handle_count 只能用作调试辅助工具。请勿使用它来检查不可信进程是否无法修改内核对象。由于系统调度器的异步特性，可能存在这样一个时间段：在此期间，即使最后一个句柄从一个进程转移到另一个进程，上一个句柄所有者也可以修改对象。
ZX_INFO_PROCESS_HANDLE_STATS
handle 类型：Process
buffer 类型：zx_info_process_handle_stats_t[1]
typedef struct zx_info_process_handle_stats {
// The number of outstanding handles to kernel objects of each type.
uint32_t handle_count[ZX_OBJ_TYPE_UPPER_BOUND];
} zx_info_process_handle_stats_t;
ZX_INFO_HANDLE_TABLE
handle 类型：Process
buffer 类型：zx_info_handle_extended_t[n]
返回一个 zx_info_handle_extended_t 数组，对应于调用时 Process 中的每个句柄。内核可确保返回的句柄一致。
typedef struct zx_info_handle_extended {
// The object type: channel, event, socket, etc.
zx_obj_type_t type;
// The handle value, which is only valid for the process that
// was passed to ZX_INFO_HANDLE_TABLE.
zx_handle_t handle_value;
// The immutable rights assigned to the handle. Two handles that
// have the same koid and the same rights are equivalent and
// interchangeable.
zx_rights_t rights;
uint32_t reserved;
// The unique id assigned by kernel to the object referenced by the
// handle.
zx_koid_t koid;
// If the object referenced by the handle is related to another (such
// as the other end of a channel, or the parent of a job) then
// |related_koid| is the koid of that object, otherwise it is zero.
// This relationship is immutable: an object's |related_koid| does
// not change even if the related object no longer exists.
zx_koid_t related_koid;
// If the object referenced by the handle has a peer, like the
// other end of a channel, then this is the koid of the process
// which currently owns it.
zx_koid_t peer_owner_koid;
} zx_info_handle_extended_t;
请注意，进程可能对没有其句柄的对象具有实时引用。例如，正在运行的线程的所有句柄均已关闭。
ZX_INFO_JOB
handle 类型：Job
buffer 类型：zx_info_job_t[1]
typedef struct zx_info_job {
// The job's return code; only valid if |exited| is true.
// If the job was killed, it will be one of the ZX_TASK_RETCODE values.
int64_t return_code;
// If true, the job has exited and |return_code| is valid.
bool exited;
// True if the ZX_PROP_JOB_KILL_ON_OOM property was set.
bool kill_on_oom;
// True if a debugger is attached to the job.
bool debugger_attached;
} zx_info_job_t;
请注意，|exited| 会在执行 |zx_task_kill| 或等效项（例如 OOM 终止）后立即报告作业已退出，但子作业和进程可能仍在退出过程中。
ZX_INFO_PROCESS
handle 类型：Process
buffer 类型：zx_info_process_t[1]
typedef struct zx_info_process {
// The process's return code; only valid if the
// |ZX_PROCESS_INFO_FLAG_EXITED| flag is set. If the process was killed, it
// will be one of the |ZX_TASK_RETCODE| values.
int64_t return_code;
// The monotonic time at which `zx_process_start()` was called, only valid
// if the |ZX_INFO_PROCESS_FLAG_STARTED| flag is set.
zx_time_t start_time;
// Bitwise OR of ZX_INFO_PROCESS_FLAG_* values.
uint32_t flags;
} zx_info_process_t;
请注意，在 |zx_task_kill| 之后，|flags| 将立即报告进程已退出（即它将包含 ZX_INFO_PROCESS_FLAG_EXITED），但子线程可能仍在退出过程中。
ZX_INFO_PROCESS_THREADS
handle 类型：Process
buffer 类型：zx_koid_t[n]
返回一个 zx_koid_t 数组，此数组对应于当时进程中正在运行的每个线程。
注意：获取消息串列表本身就属于少儿不宜的行为。可通过首先挂起所有线程来缓解这个问题，但请注意，外部线程可以创建新线程。actual 包含 buffer 中返回的线程数。avail 将包含获取线程列表时的进程线程总数，可能会大于 actual。
ZX_INFO_THREAD
handle 类型：Thread
buffer 类型：zx_info_thread_t[1]
typedef struct zx_info_thread {
// One of ZX_THREAD_STATE_* values.
uint32_t state;
// If |state| is ZX_THREAD_STATE_BLOCKED_EXCEPTION, the thread has gotten
// an exception and is waiting for the exception to be handled by the
// specified channel.
// The value is one of ZX_EXCEPTION_CHANNEL_TYPE_*.
uint32_t wait_exception_channel_type;
// CPUs this thread may be scheduled on, as specified by
// a profile object applied to this thread.
//
// The kernel may not internally store invalid CPUs in the mask, so
// this may not exactly match the mask applied to the thread for
// CPUs beyond what the system is able to use.
zx_cpu_set_t cpu_affinity_mask;
} zx_info_thread_t;
此结构体中的值目前主要用于参考和调试。
各种 ZX_THREAD_STATE_ 值由
#include <zircon/syscalls/object.h>
ZX_THREAD_STATE_NEW：线程已创建，但尚未开始运行。ZX_THREAD_STATE_RUNNING：线程正在正常运行用户代码。ZX_THREAD_STATE_SUSPENDED：由于zx_task_suspend()而停止。ZX_THREAD_STATE_BLOCKED：在系统调用中或处理异常。此值绝不会单独返回。请参阅下面的 `ZX_THREAD_STATEBLOCKED`* 部分。ZX_THREAD_STATE_DYING：线程正在终止，但尚未停止。ZX_THREAD_STATE_DEAD：线程已停止运行。
当线程在阻塞系统调用中停止或在异常中停止时，state 中返回的值是以下值之一：
ZX_THREAD_STATE_BLOCKED_EXCEPTION：线程在异常中停止。ZX_THREAD_STATE_BLOCKED_SLEEPING：线程在zx_nanosleep()中停止。ZX_THREAD_STATE_BLOCKED_FUTEX：线程在zx_futex_wait()中停止。ZX_THREAD_STATE_BLOCKED_PORT：线程在zx_port_wait()中停止。ZX_THREAD_STATE_BLOCKED_CHANNEL：线程在zx_channel_call()中停止。ZX_THREAD_STATE_BLOCKED_WAIT_ONE：线程在zx_object_wait_one()中停止。ZX_THREAD_STATE_BLOCKED_WAIT_MANY：线程在zx_object_wait_many()中停止。ZX_THREAD_STATE_BLOCKED_INTERRUPT：线程在zx_interrupt_wait()中停止。
各种 ZX_EXCEPTION_CHANNEL_TYPE_ 值由
#include <zircon/syscalls/exception.h>
ZX_EXCEPTION_CHANNEL_TYPE_NONEZX_EXCEPTION_CHANNEL_TYPE_DEBUGGERZX_EXCEPTION_CHANNEL_TYPE_THREADZX_EXCEPTION_CHANNEL_TYPE_PROCESSZX_EXCEPTION_CHANNEL_TYPE_JOBZX_EXCEPTION_CHANNEL_TYPE_JOB_DEBUGGER
ZX_INFO_THREAD_EXCEPTION_REPORT
handle 类型：Thread
buffer 类型：zx_exception_report_t[1]
#include <zircon/syscalls/exception.h>
如果线程当前处于异常状态，正在等待异常响应，则会将异常报告作为单个 zx_exception_report_t 返回，其状态为 ZX_OK。
如果线程未处于异常状态且正在等待异常响应，则返回 ZX_ERR_BAD_STATE。
ZX_INFO_THREAD_STATS
handle 类型：Thread
buffer 类型：zx_info_thread_stats[1]
typedef struct zx_info_thread_stats {
// Total accumulated running time of the thread.
//
// Note: See zx_info_task_runtime for queue time in addition to runtime.
zx_duration_t total_runtime;
// CPU number that this thread was last scheduled on, or ZX_INFO_INVALID_CPU
// if the thread has never been scheduled on a CPU. By the time this call
// returns, the thread may have been scheduled elsewhere, so this
// information should only be used as a hint or for statistics.
uint32_t last_scheduled_cpu;
} zx_info_thread_stats_t;
如果线程已退出，则返回 ZX_ERR_BAD_STATE。
ZX_INFO_GUEST_STATS
handle 类型：Resource（具体而言是信息资源）
buffer 类型：zx_info_guest_stats_t[1]
// Each machine has its own format for the same ZX_INFO_GUEST_STATS topic.
// In each build, zx_info_guest_stats_t is a typedef alias for the type.
// Cross-tools can select the machine-specific type to use based on the
// source of the data they are working with.
typedef struct zx_arm64_info_guest_stats {
uint32_t cpu_number;
uint32_t flags;
uint64_t vm_entries;
uint64_t vm_exits;
uint64_t wfi_wfe_instructions;
uint64_t instruction_aborts;
uint64_t data_aborts;
uint64_t system_instructions;
uint64_t smc_instructions;
uint64_t interrupts;
} zx_arm64_info_guest_stats_t;
typedef struct zx_x86_64_info_guest_stats {
uint32_t cpu_number;
uint32_t flags;
uint64_t vm_entries;
uint64_t vm_exits;
uint64_t interrupts;
uint64_t interrupt_windows;
uint64_t cpuid_instructions;
uint64_t hlt_instructions;
uint64_t control_register_accesses;
uint64_t io_instructions;
uint64_t rdmsr_instructions;
uint64_t wrmsr_instructions;
uint64_t ept_violations;
uint64_t xsetbv_instructions;
uint64_t pause_instructions;
uint64_t vmcall_instructions;
} zx_x86_64_info_guest_stats;
ZX_INFO_CPU_STATS
handle 类型：Resource（具体而言是信息资源）
buffer 类型：zx_info_cpu_stats_t[1]
typedef struct zx_info_cpu_stats {
uint32_t cpu_number;
uint32_t flags;
zx_duration_t idle_time;
// kernel scheduler counters
uint64_t reschedules;
uint64_t context_switches;
uint64_t irq_preempts;
uint64_t preempts;
uint64_t yields;
// cpu level interrupts and exceptions
uint64_t ints; // hardware interrupts, minus timer interrupts
// inter-processor interrupts
uint64_t timer_ints; // timer interrupts
uint64_t timers; // timer callbacks
uint64_t page_faults; // (deprecated, returns 0)
uint64_t exceptions; // (deprecated, returns 0)
uint64_t syscalls;
// inter-processor interrupts
uint64_t reschedule_ipis;
uint64_t generic_ipis;
} zx_info_cpu_stats_t;
ZX_INFO_VMAR
handle 类型：VM Address Region
buffer 类型：zx_info_vmar_t[1]
typedef struct zx_info_vmar {
// Base address of the region.
uintptr_t base;
// Length of the region, in bytes.
size_t len;
} zx_info_vmar_t;
这将返回一个 zx_info_vmar_t，用于描述 VMAR 所占用的地址空间范围。
ZX_INFO_VMO
handle 类型：VM Object
buffer 类型：zx_info_vmo_t[1]
typedef struct zx_info_vmo {
// The koid of this VMO.
zx_koid_t koid;
// The name of this VMO.
char name[ZX_MAX_NAME_LEN];
// The size of this VMO; i.e., the amount of virtual address space it
// would consume if mapped.
uint64_t size_bytes;
// If this VMO is a child , the koid of its parent. Otherwise, zero.
// See |flags| for the type of child.
zx_koid_t parent_koid;
// The number of children of this VMO, if any.
size_t num_children;
// The number of times this VMO is currently mapped into VMARs.
// Note that the same process will often map the same VMO twice,
// and both mappings will be counted here. (I.e., this is not a count
// of the number of processes that map this VMO; see share_count.)
size_t num_mappings;
// An estimate of the number of unique address spaces that
// this VMO is mapped into. Every process has its own address space,
// and so does the kernel.
size_t share_count;
// Bitwise OR of ZX_INFO_VMO_* values.
uint32_t flags;
// If |ZX_INFO_VMO_TYPE(flags) == ZX_INFO_VMO_TYPE_PAGED|, the amount of
// memory currently allocated to this VMO; i.e., the amount of physical
// memory it consumes. Undefined otherwise.
uint64_t committed_bytes;
// If |flags & ZX_INFO_VMO_VIA_HANDLE|, the handle rights.
//
// If |flags & ZX_INFO_VMO_VIA_IOB_HANDLE|, the effective combined
// handle rights for the IOB region and containing IOB.
//
// Undefined otherwise.
zx_rights_t handle_rights;
// VMO mapping cache policy. One of ZX_CACHE_POLICY_*
uint32_t cache_policy;
// Amount of kernel memory, in bytes, allocated to track metadata
// associated with this VMO.
uint64_t metadata_bytes;
// Running counter of the number of times the kernel, without user request,
// performed actions on this VMO that would have caused |committed_bytes| to
// report a different value.
uint64_t committed_change_events;
// If |ZX_INFO_VMO_TYPE(flags) == ZX_INFO_VMO_TYPE_PAGED|, the amount of
// content that has been populated and is being tracked by this vmo. This
// can be greater than |committed_bytes| where content might be compressed
// or otherwise tracked in a way that does not correlate directly to being
// committed.
uint64_t populated_bytes;
} zx_info_vmo_t;
这将返回一个 zx_info_vmo_t，用于描述 VMO 的各种属性。
ZX_INFO_SOCKET
handle 类型：Socket
buffer 类型：zx_info_socket_t[1]
typedef struct zx_info_socket {
// The options passed to zx_socket_create().
uint32_t options;
// The maximum size of the receive buffer of a socket, in bytes.
//
// The receive buffer may become full at a capacity less than the maximum
// due to overhead.
size_t rx_buf_max;
// The size of the receive buffer of a socket, in bytes.
size_t rx_buf_size;
// The amount of data, in bytes, that is available for reading in a single
// zx_socket_read call.
//
// For stream sockets, this value will match |rx_buf_size|. For datagram
// sockets, this value will be the size of the next datagram in the receive
// buffer.
size_t rx_buf_available;
// The maximum size of the transmit buffer of a socket, in bytes.
//
// The transmit buffer may become full at a capacity less than the maximum
// due to overhead.
//
// Will be zero if the peer endpoint is closed.
size_t tx_buf_max;
// The size of the transmit buffer of a socket, in bytes.
//
// Will be zero if the peer endpoint is closed.
size_t tx_buf_size;
} zx_info_socket_t;
ZX_INFO_TIMER
handle 类型：Timer
buffer 类型：zx_info_timer_t[1]
typedef struct zx_info_timer {
// The options passed to zx_timer_create().
uint32_t options;
// The deadline with respect to ZX_CLOCK_MONOTONIC at which the timer will
// fire next.
//
// This value will be zero if the timer is not set to fire.
zx_time_t deadline;
// Specifies a range from deadline - slack to deadline + slack during which
// the timer is allowed to fire. The system uses this parameter as a hint to
// coalesce nearby timers.
//
// The precise coalescing behavior is controlled by the options parameter
// specified when the timer was created.
//
// This value will be zero if the timer is not set to fire.
zx_duration_t slack;
} zx_info_timer_t;
ZX_INFO_JOB_CHILDREN
handle 类型：Job
buffer 类型：zx_koid_t[n]
返回一个 zx_koid_t 数组，其中每个直接子 Job 与提供的 Job 句柄对应。
ZX_INFO_JOB_PROCESSES
handle 类型：Job
buffer 类型：zx_koid_t[n]
返回一个 zx_koid_t 数组，提供的作业句柄的每个直接子级进程对应一个。
ZX_INFO_TASK_STATS
handle 类型：Process
buffer 类型：zx_info_task_stats_t[1]
返回任务所用资源（如内存）的统计信息。
typedef struct zx_info_task_stats {
// The total size of mapped memory ranges in the task.
// Not all will be backed by physical memory.
size_t mem_mapped_bytes;
// For the fields below, a byte is considered committed if it's backed by
// physical memory. Some of the memory may be double-mapped, and thus
// double-counted.
// Committed memory that is only mapped into this task.
size_t mem_private_bytes;
// Committed memory that is mapped into this and at least one other task.
size_t mem_shared_bytes;
// A number that estimates the fraction of mem_shared_bytes that this
// task is responsible for keeping alive.
//
// An estimate of:
// For each shared, committed byte:
// mem_scaled_shared_bytes += 1 / (number of tasks mapping this byte)
//
// This number is strictly smaller than mem_shared_bytes.
size_t mem_scaled_shared_bytes;
} zx_info_task_stats_t;
其他错误：
ZX_ERR_BAD_STATE：如果目标进程已终止
ZX_INFO_TASK_RUNTIME
handle 类型：Job、Process 或 Thread
buffer 类型：zx_info_task_runtime_t[1]
返回有关任务运行时的统计信息。
// Info on the runtime of a task.
typedef struct zx_info_task_runtime {
// The total amount of time this task and its children were
// running on a CPU (not blocked).
// * Threads include only their own runtime.
// * Processes include the runtime for all of their threads (including threads that previously
// exited).
// * Jobs include the runtime for all of their processes (including processes that previously
// exited).
zx_duration_t cpu_time;
// The total amount of time this task and its children were queued
// to run (ready) but not actually using a CPU.
// * Threads include only their own queue time.
// * Processes include the queue time for all of their threads (including threads that
// previously exited).
// * Jobs include the queue time for all of their processes (including processes that previously
// exited).
zx_duration_t queue_time;
// The total amount of time this task and its children spent handling page faults.
// * Threads include only their own page fault handling time.
// * Processes include the page fault time for all of their threads (including threads that
// previously exited).
// * Jobs include the page fault time for all of their processes (including processes that
// previously exited).
zx_duration_t page_fault_time;
// The total amount of time this task and its children spent waiting on contended kernel locks.
// * Threads include only their own wait time.
// * Processes include the wait time for all of their threads (including threads that
// previously exited).
// * Jobs include the wait time for all of their processes (including processes that
// previously exited).
zx_duration_t lock_contention_time;
} zx_info_task_runtime_t;
任务的运行时间不包括等待事件或 I/O 所花费的暂停或阻塞时间。这些统计信息可能会用于：
- 估算任务已使用的 CPU 时间。
- 估算任务因其他任务（队列时间）、页面错误处理程序和内核锁争用而经历的延迟时间。
ZX_INFO_PROCESS_MAPS
handle 类型：Process，包含 ZX_RIGHT_READ
buffer 类型：zx_info_maps_t[n]
zx_info_maps_t 数组是目标进程的 Aspace/VMAR/Mapping 树的深度优先预订遍历。根据预订顺序，遍历的基地址将按升序排列。
typedef struct zx_info_maps {
// Name if available; empty string otherwise.
char name[ZX_MAX_NAME_LEN];
// Base address.
zx_vaddr_t base;
// Size in bytes.
size_t size;
// The depth of this node in the tree.
// Can be used for indentation, or to rebuild the tree from an array
// of zx_info_maps_t entries, which will be in depth-first pre-order.
size_t depth;
// The type of this entry; indicates which union entry is valid.
uint32_t type; // zx_info_maps_type_t
union {
zx_info_maps_mapping_t mapping;
// No additional fields for other types.
} u;
} zx_info_maps_t;
typedef struct zx_info_maps_mapping {
// MMU flags for the mapping.
// Bitwise OR of ZX_VM_PERM_{READ,WRITE,EXECUTE} values.
zx_vm_option_t mmu_flags;
uint8_t padding1[4];
// koid of the mapped VMO or IOB region.
zx_koid_t vmo_koid;
// Offset into the above VMO or IOB region.
uint64_t vmo_offset;
// The number of PAGE_SIZE pages in the mapped region of the VMO or
// IOB region that are backed by physical memory.
size_t committed_pages;
// The number of PAGE_SIZE pages of content that have been populated and are
// being tracked in the mapped region of the VMO or IOB region. This can be
// greater than |committed_pages| where pages might be compressed or otherwise
// tracked in a way that does not correlate directly to being committed.
size_t populated_pages;
} zx_info_maps_mapping_t;
每个条目的 depth 字段描述它与它前面的节点的关系。Depth 0 为根 Aspace，深度 1 为根 VMAR，所有其他条目的深度均为 2 或更大。
如需全面了解进程如何使用其 VMO 以及各种进程如何使用 VMO，您可能需要将这些信息与 ZX_INFO_PROCESS_VMOS 结合使用。
如需查看本主题的示例用户以及如何按 koid 转储任意进程的映射，请参阅 vmaps 命令行工具。
其他错误：
ZX_ERR_ACCESS_DENIED：如果未提供相应权限，ZX_ERR_BAD_STATE：如果目标进程已终止，或者其地址空间已被销毁
ZX_INFO_PROCESS_VMOS
handle 类型：Process，包含 ZX_RIGHT_READ
buffer 类型：zx_info_vmo_t[n]
zx_info_vmo_t 数组是目标进程指向的所有 VMO 的列表。一些 VMO 被映射，一些被 VMO 或 IOB 句柄指向，还有一些 VMO 是这些对象的组合。所返回结构体的 flags 字段将指示 ZX_INFO_VMO_VIA_HANDLE、ZX_INFO_VMO_VIA_IOB_HANDLE 或 ZX_INFO_VMO_VIA_MAPPING 中的一个，以允许区分。
如需全面了解进程如何使用其 VMO 以及各种进程如何使用 VMO，您可能需要将这些信息与 ZX_INFO_PROCESS_MAPS 结合使用。
// Describes a VMO.
typedef struct zx_info_vmo {
// The koid of this VMO.
zx_koid_t koid;
// The name of this VMO.
char name[ZX_MAX_NAME_LEN];
// The size of this VMO; i.e., the amount of virtual address space it
// would consume if mapped.
uint64_t size_bytes;
// If this VMO is a child , the koid of its parent. Otherwise, zero.
// See |flags| for the type of child.
zx_koid_t parent_koid;
// The number of children of this VMO, if any.
size_t num_children;
// The number of times this VMO is currently mapped into VMARs.
// Note that the same process will often map the same VMO twice,
// and both mappings will be counted here. (I.e., this is not a count
// of the number of processes that map this VMO; see share_count.)
size_t num_mappings;
// An estimate of the number of unique address spaces that
// this VMO is mapped into. Every process has its own address space,
// and so does the kernel.
size_t share_count;
// Bitwise OR of ZX_INFO_VMO_* values.
uint32_t flags;
// If |ZX_INFO_VMO_TYPE(flags) == ZX_INFO_VMO_TYPE_PAGED|, the amount of
// memory currently allocated to this VMO; i.e., the amount of physical
// memory it consumes. Undefined otherwise.
uint64_t committed_bytes;
// If |flags & ZX_INFO_VMO_VIA_HANDLE|, the handle rights.
//
// If |flags & ZX_INFO_VMO_VIA_IOB_HANDLE|, the effective combined
// handle rights for the IOB region and containing IOB.
//
// Undefined otherwise.
zx_rights_t handle_rights;
// VMO mapping cache policy. One of ZX_CACHE_POLICY_*
uint32_t cache_policy;
// Amount of kernel memory, in bytes, allocated to track metadata
// associated with this VMO.
uint64_t metadata_bytes;
// Running counter of the number of times the kernel, without user request,
// performed actions on this VMO that would have caused |committed_bytes| to
// report a different value.
uint64_t committed_change_events;
// If |ZX_INFO_VMO_TYPE(flags) == ZX_INFO_VMO_TYPE_PAGED|, the amount of
// content that has been populated and is being tracked by this vmo. This
// can be greater than |committed_bytes| where content might be compressed
// or otherwise tracked in a way that does not correlate directly to being
// committed.
uint64_t populated_bytes;
} zx_info_vmo_t;
如需查看本主题的示例用户以及如何按 koid 转储任意进程的 VMO，请参阅 vmos 命令行工具。
ZX_INFO_KMEM_STATS
handle 类型：Resource（具体而言是信息资源）
buffer 类型：zx_info_kmem_stats_t[1]
返回有关内核内存使用情况的信息。
typedef struct zx_info_kmem_stats {
// The total amount of physical memory available to the system.
// Note, the values below may not exactly add up to this total.
size_t total_bytes;
// The amount of unallocated memory.
size_t free_bytes;
// The amount of memory reserved by and mapped into the kernel for reasons
// not covered by other fields in this struct. Typically for readonly data
// like the ram disk and kernel image, and for early-boot dynamic memory.
size_t wired_bytes;
// The amount of memory allocated to the kernel heap.
size_t total_heap_bytes;
// The portion of |total_heap_bytes| that is not in use.
size_t free_heap_bytes;
// The amount of memory committed to VMOs, both kernel and user.
// A superset of all userspace memory.
// Does not include certain VMOs that fall under |wired_bytes|.
size_t vmo_bytes;
// The amount of memory used for architecture-specific MMU metadata
// like page tables.
size_t mmu_overhead_bytes;
// Non-free memory that isn't accounted for in any other field.
size_t other_bytes;
} zx_info_kmem_stats_t;
ZX_INFO_KMEM_STATS_EXTENDED
handle 类型：Resource（具体而言是信息资源）
buffer 类型：zx_info_kmem_stats_extended_t[1]
返回有关内核内存使用情况的信息，包括 ZX_INFO_KMEM_STATS 主题返回的信息，以及收集开销更高的一些额外信息。
typedef struct zx_info_kmem_stats_extended {
// The total amount of physical memory available to the system.
uint64_t total_bytes;
// The amount of unallocated memory.
uint64_t free_bytes;
// The amount of memory reserved by and mapped into the kernel for reasons
// not covered by other fields in this struct. Typically for readonly data
// like the ram disk and kernel image, and for early-boot dynamic memory.
uint64_t wired_bytes;
// The amount of memory allocated to the kernel heap.
uint64_t total_heap_bytes;
// The portion of |total_heap_bytes| that is not in use.
uint64_t free_heap_bytes;
// The amount of memory committed to VMOs, both kernel and user.
// A superset of all userspace memory.
// Does not include certain VMOs that fall under |wired_bytes|.
uint64_t vmo_bytes;
// The amount of memory committed to pager-backed VMOs.
uint64_t vmo_pager_total_bytes;
// The amount of memory committed to pager-backed VMOs, that has been most
// recently accessed, and would not be eligible for eviction by the kernel
// under memory pressure.
uint64_t vmo_pager_newest_bytes;
// The amount of memory committed to pager-backed VMOs, that has been least
// recently accessed, and would be the first to be evicted by the kernel
// under memory pressure.
uint64_t vmo_pager_oldest_bytes;
// The amount of memory committed to discardable VMOs that is currently
// locked, or unreclaimable by the kernel under memory pressure.
uint64_t vmo_discardable_locked_bytes;
// The amount of memory committed to discardable VMOs that is currently
// unlocked, or reclaimable by the kernel under memory pressure.
uint64_t vmo_discardable_unlocked_bytes;
// The amount of memory used for architecture-specific MMU metadata
// like page tables.
uint64_t mmu_overhead_bytes;
// The amount of memory in use by IPC.
uint64_t ipc_bytes;
// Non-free memory that isn't accounted for in any other field.
uint64_t other_bytes;
// The amount of memory in VMOs that would otherwise be tracked for
// reclamation, but has had reclamation disabled.
uint64_t vmo_reclaim_disabled_bytes;
} zx_info_kmem_stats_extended_t;
ZX_INFO_KMEM_STATS_COMPRESSION
handle 类型：Resource（具体而言是信息资源）
buffer 类型：zx_info_kmem_stats_compression_t[1]
返回与已压缩内存子系统相关的内核内存使用情况信息。
typedef struct zx_info_kmem_stats_compression {
// Size in bytes of the content that is currently being compressed and stored.
uint64_t uncompressed_storage_bytes;
// Size in bytes of all memory, including metadata, fragmentation and other
// overheads, of the compressed memory area. Note that due to base book
// keeping overhead this could be non-zero, even when
// |uncompressed_content_bytes| is zero.
uint64_t compressed_storage_bytes;
// Size in bytes of any fragmentation in the compressed memory area.
uint64_t compressed_fragmentation_bytes;
// Total amount of CPU time spent on compression across all threads.
// Compression may happen in parallel and so this can be larger than
// wall clock time.
zx_duration_t compression_time;
// Total amount of time decompression has spent on a CPU across all threads.
// Decompression may happen in parallel and so this can increase faster than
// wall clock time.
zx_duration_t decompression_time;
// Total number of times compression has been done on a page, regardless of
// whether the compressed result was ultimately retained.
uint64_t total_page_compression_attempts;
// How many of the total compression attempts were considered failed and
// were not stored. An example reason for failure would be a page not being
// compressed sufficiently to be considered worth storing.
uint64_t failed_page_compression_attempts;
// Number of times pages have been decompressed.
uint64_t total_page_decompressions;
// Number of times a page was removed from storage without needing to be
// decompressed. An example that would cause this is a VMO being destroyed.
uint64_t compressed_page_evictions;
// How many pages compressed due to the page being inactive, but without
// there being memory pressure.
uint64_t eager_page_compressions;
// How many pages compressed due to general memory pressure. This excludes pages
// compressed due to critical memory pressure.
uint64_t memory_pressure_page_compressions;
// How many pages compressed due to attempting to avoid OOM or near OOM
// scenarios.
uint64_t critical_memory_page_compressions;
// The nanoseconds in the base unit of time for
// |pages_decompressed_within_log_time|.
uint64_t pages_decompressed_unit_ns;
// How long pages spent compressed before being decompressed, grouped in log
// buckets. Pages that got evicted, and hence were not decompressed, are not
// counted here. Buckets are in |pages_decompressed_unit_ns| and round up
// such that:
// 0: Pages decompressed in <1 unit
// 1: Pages decompressed between 1 and 2 units
// 2: Pages decompressed between 2 and 4 units
// ...
// 7: Pages decompressed between 64 and 128 units
// How many pages are held compressed for longer than 128 units can be
// inferred by subtracting from |total_page_decompressions|.
uint64_t pages_decompressed_within_log_time[8];
} zx_info_kmem_stats_compression_t;
ZX_INFO_RESOURCE
handle 类型：Resource
buffer 类型：zx_info_resource_t[1]
通过对象句柄返回有关资源对象的信息。
typedef struct zx_info_resource {
// The resource kind; resource object kinds are described in resource.md
uint32_t kind;
// Resource's creation flags
uint32_t flags;
// Resource's base value (inclusive)
uint64_t base;
// Resource's length value
size_t size;
char name[ZX_MAX_NAME_LEN];
} zx_info_resource_t;
资源类型为以下之一：
ZX_RSRC_KIND_ROOTZX_RSRC_KIND_MMIOZX_RSRC_KIND_IOPORTZX_RSRC_KIND_IRQZX_RSRC_KIND_SMCZX_RSRC_KIND_SYSTEM
ZX_INFO_BTI
handle 类型：Bus Transaction Initiator
buffer 类型：zx_info_bti_t[1]
typedef struct zx_info_bti {
// zx_bti_pin will always be able to return addresses that are contiguous for at
// least this many bytes. E.g. if this returns 1MB, then a call to
// zx_bti_pin() with a size of 2MB will return at most two physically-contiguous runs.
// If the size were 2.5MB, it will return at most three physically-contiguous runs.
uint64_t minimum_contiguity;
// The number of bytes in the device's address space (UINT64_MAX if 2^64).
uint64_t aspace_size;
// The count of the pinned memory object tokens. Requesting this count is
// racy, so this should only be used for informative reasons.
uint64_t pmo_count;
// The count of the quarantined pinned memory object tokens. Requesting this count is
// racy, so this should only be used for informative reasons.
uint64_t quarantine_count;
} zx_info_bti_t;
主题 ZX_INFO_IOB
handle 类型：IOBuffer
buffer 类型：zx_info_iob_t[1]
返回有关整个 IOB 实例的信息。
typedef struct zx_info_iob {
// The value of the *options* parameter passed to `zx_iob_create`.
uint64_t options;
// The number of regions in the IOB.
uint32_t region_count;
// Reserved for future extensions.
uint8_t padding[4];
} zx_info_iob_t;
主题 ZX_INFO_IOB_REGIONS
以 zx_iob_region_info_t 数组的形式返回有关 IOB 的每个区域的信息
handle 类型：IOBuffer
buffer 类型：zx_iob_region_info_t[n]
struct zx_iob_region_info_t { // 区域说明，包含可能交换的访问位。 zx_iob_region_t region; /// 底层内存对象的 koid。 zx_koid_t koid; };
访问修饰符位经过交换，以便 Ep0 访问位反映进行查询的端点的访问，而 Ep1 位反映对另一个端点的访问，这样就可以确定本地和远程句柄的访问，而无需在创建时知道哪个句柄是 Ep0 和 Ep1。
权限
如果 topic 为 ZX_INFO_PROCESS，handle 的类型必须为 ZX_OBJ_TYPE_PROCESS，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_JOB，handle 的类型必须为 ZX_OBJ_TYPE_JOB，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_PROCESS_THREADS，handle 的类型必须为 ZX_OBJ_TYPE_PROCESS，且具有 ZX_RIGHT_ENUMERATE。
如果 topic 为 ZX_INFO_JOB_CHILDREN，handle 的类型必须为 ZX_OBJ_TYPE_JOB，且具有 ZX_RIGHT_ENUMERATE。
如果 topic 为 ZX_INFO_JOB_PROCESSES，handle 的类型必须为 ZX_OBJ_TYPE_JOB，且具有 ZX_RIGHT_ENUMERATE。
如果 topic 为 ZX_INFO_THREAD，handle 的类型必须为 ZX_OBJ_TYPE_THREAD，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_THREAD_EXCEPTION_REPORT，handle 的类型必须为 ZX_OBJ_TYPE_THREAD，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_THREAD_STATS，handle 的类型必须为 ZX_OBJ_TYPE_THREAD，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_TASK_STATS，handle 的类型必须为 ZX_OBJ_TYPE_PROCESS，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_PROCESS_MAPS，handle 的类型必须为 ZX_OBJ_TYPE_PROCESS，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_PROCESS_VMOS，handle 的类型必须为 ZX_OBJ_TYPE_PROCESS，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_VMO，handle 的类型必须为 ZX_OBJ_TYPE_VMO。
如果 topic 为 ZX_INFO_VMAR，handle 的类型必须为 ZX_OBJ_TYPE_VMAR，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_GUEST_STATS，handle 必须具有以 ZX_RSRC_SYSTEM_INFO_BASE 为基数的资源种类 ZX_RSRC_KIND_SYSTEM。
如果 topic 为 ZX_INFO_CPU_STATS，handle 必须具有以 ZX_RSRC_SYSTEM_INFO_BASE 为基数的资源种类 ZX_RSRC_KIND_SYSTEM。
如果 topic 为 ZX_INFO_KMEM_STATS，handle 必须具有以 ZX_RSRC_SYSTEM_INFO_BASE 为基数的资源种类 ZX_RSRC_KIND_SYSTEM。
如果 topic 为 ZX_INFO_KMEM_STATS_EXTENDED，handle 必须具有以 ZX_RSRC_SYSTEM_INFO_BASE 为基数的资源种类 ZX_RSRC_KIND_SYSTEM。
如果 topic 为 ZX_INFO_RESOURCE，handle 的类型必须为 ZX_OBJ_TYPE_RESOURCE，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_HANDLE_COUNT，handle 必须具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_BTI，handle 的类型必须为 ZX_OBJ_TYPE_BTI，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_PROCESS_HANDLE_STATS，handle 的类型必须为 ZX_OBJ_TYPE_PROCESS，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_SOCKET，handle 的类型必须为 ZX_OBJ_TYPE_SOCKET，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_MSI，handle 的类型必须为 ZX_OBJ_TYPE_MSI，且具有 ZX_RIGHT_INSPECT。
如果 topic 为 ZX_INFO_TASK_RUNTIME，handle 必须为 ZX_OBJ_TYPE_THREAD、ZX_OBJ_TYPE_PROCESS 或 ZX_OBJ_TYPE_JOB 类型，且具有 ZX_RIGHT_INSPECT。
返回值
zx_object_get_info() 会在成功时返回 ZX_OK。如果失败，则返回负错误值。
错误
ZX_ERR_BAD_HANDLE 句柄不是有效句柄。
ZX_ERR_WRONG_TYPE 标识名不是主题的适当类型
ZX_ERR_ACCESS_DENIED：如果 handle 没有执行相应操作所需的权限。
ZX_ERR_INVALID_ARGS buffer、actual 或 avail 是无效指针。
ZX_ERR_NO_MEMORY因内存不足而失败。用户空间没有什么方法来处理此（不太可能）错误。在以后的 build 中，此错误不会再出现。
ZX_ERR_BUFFER_TOO_SMALL 主题返回固定数量的记录，但提供的缓冲区不足以存储这些记录。
ZX_ERR_NOT_SUPPORTED 主题不存在。
示例
bool is_handle_valid(zx_handle_t handle) {
return zx_object_get_info(
handle, ZX_INFO_HANDLE_VALID, NULL, 0, NULL, NULL) == ZX_OK;
}
zx_koid_t get_object_koid(zx_handle_t handle) {
zx_info_handle_basic_t info;
if (zx_object_get_info(handle, ZX_INFO_HANDLE_BASIC,
&info, sizeof(info), NULL, NULL) != ZX_OK) {
return 0;
}
return info.koid;
}
void examine_threads(zx_handle_t proc) {
zx_koid_t threads[128];
size_t count, avail;
if (zx_object_get_info(proc, ZX_INFO_PROCESS_THREADS, threads,
sizeof(threads), &count, &avail) != ZX_OK) {
// Error!
} else {
if (avail > count) {
// More threads than space in array;
// could call again with larger array.
}
for (size_t n = 0; n < count; n++) {
do_something(thread[n]);
}
}
}