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关于获取进程句柄的问题

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Jun 07, 2016 pm 03:31 PM

useabouthandleObtainprocessquestion

使用CreateProcess创建一个进程后，PROCESS_INFORMATION结构中会包含进程的handle，和唯一存在的进程 ID 而后使用openprocess打开进程时，根据第一个参数（dwDesiredAccess：想拥有的该进程访问权限 PROCESS_ALL_ACCESS //所有能获得的权限 PROCES

使用CreateProcess创建一个进程后，PROCESS_INFORMATION结构中会包含进程的handle，和唯一存在的进程ID

而后使用openprocess打开进程时，根据第一个参数

（dwDesiredAccess：想拥有的该进程访问权限
PROCESS_ALL_ACCESS //所有能获得的权限
PROCESS_CREATE_PROCESS //需要创建一个进程
PROCESS_CREATE_THREAD   //需要创建一个线程
PROCESS_DUP_HANDLE      //重复使用DuplicateHandle句柄
PROCESS_QUERY_INFORMATION   //获得进程信息的权限，如它的退出代码、优先级
PROCESS_QUERY_LIMITED_INFORMATION /*获得某些信息的权限，如果获得了PROCESS_QUERY_INFORMATION，也拥有PROCESS_QUERY_LIMITED_INFORMATION权限*/
PROCESS_SET_INFORMATION    //设置某些信息的权限，如进程优先级
PROCESS_SET_QUOTA          //设置内存限制的权限，使用SetProcessWorkingSetSize
PROCESS_SUSPEND_RESUME     //暂停或恢复进程的权限
PROCESS_TERMINATE          //终止一个进程的权限，使用TerminateProcess
PROCESS_VM_OPERATION       //操作进程内存空间的权限(可用VirtualProtectEx和WriteProcessMemory)
PROCESS_VM_READ            //读取进程内存空间的权限，可使用ReadProcessMemory
PROCESS_VM_WRITE           //读取进程内存空间的权限，可使用WriteProcessMemory
SYNCHRONIZE                //等待进程终止

）

的不同，返回的句柄值是不同的，而且绝对不等于PROCESS_INFORMATION中的句柄值

当程序不关闭时，用OpenProcess获取同一个进程，每次也都能得到不同的句柄值

因为OpenProcess返回的句柄是系统临时给分配的操作句柄。当你没用CloseHandle(hand)关闭这个句柄，再次调用OpenProcess获取句柄时，他又会分配一个新的句柄给你。相当于2个句柄都指向的同一个进程

实质上这些“进程句柄”其实不是真正的进程句柄，而是进程句柄在“句柄表”中的索引(偏移)，真正的进程句柄保存在进程句柄表中

若在每次句柄使用过后，关闭句柄即CloseHandle，则用OpenProcess获取同一个进程就可得到同样的句柄值

每个进程都有句柄表。该表的第一项就是进程自己的句柄，这也是为什么调用GetCurrentProcess()总是返回0x7FFFFFFF的原因。

转自：http://blog.csdn.net/lovelyloulou/article/details/5252288

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