C++ /QT 内存权限的判断函数列举

It seems like you're asking about memory permission checking functions in C++ and Qt. Here's a detailed overview:

1. C++ Memory Permission Checking Functions

a. Using System Calls (Linux/Unix)

1. mprotect function:

   • Functionality: Changes the protection of a mapped memory region.
   • Example: Used to check if a memory address is readable.

   cpp
   复制代码
   #include <sys/mman.h>
   #include <iostream>
   
   bool checkMemoryPermissions(void* addr) {
       int page_size = sysconf(_SC_PAGESIZE);  // Get system page size
       if (mprotect(addr, page_size, PROT_READ) == 0) {
           mprotect(addr, page_size, PROT_NONE);  // Restore original protection
           return true;  // Memory is readable
       } else {
           return false;  // Memory is not readable
       }
   }
   

2. /proc/self/maps file analysis:

   • Functionality: Analyzes /proc/self/maps file to retrieve memory mapping details, including permissions.

b. Using Platform-Specific APIs (Windows)

1. VirtualQuery function:

   • Functionality: Retrieves information about a range of pages in the virtual address space of the calling process.
   • Example: Used to check memory region protection flags.

   cpp
   复制代码
   #include <Windows.h>
   #include <iostream>
   
   bool checkMemoryPermissions(void* addr) {
       MEMORY_BASIC_INFORMATION mbi;
       if (VirtualQuery(addr, &mbi, sizeof(mbi)) == sizeof(mbi)) {
           return (mbi.Protect & (PAGE_READONLY | PAGE_READWRITE | PAGE_EXECUTE_READ | PAGE_EXECUTE_READWRITE)) != 0;
       }
       return false;
   }
   

2. Qt Memory Permission Checking

In Qt, memory permission checking can leverage both C++ native methods and Qt's cross-platform capabilities.

a. Qt Cross-Platform Capabilities

1. QSystemSemaphore class:

   • Functionality: Provides access to system semaphore in multi-threaded applications.
   • Example: Can be used to control memory access permissions.

   cpp
   复制代码
   #include <QSystemSemaphore>
   #include <iostream>
   
   bool checkMemoryPermissions(void* addr) {
       QSystemSemaphore semaphore;
       // Use semaphore operations to check memory permissions
       // Example code to be provided
   }
   

Summary

Memory permission checking in C++ involves using system calls like mprotect or platform-specific APIs such as VirtualQuery on Windows. Qt enhances this capability with its cross-platform support, allowing for efficient memory access control.

Keywords: C++, Qt, memory permission checking, mprotect, VirtualQuery, QSystemSemaphore