實(shí)驗(yàn)三虛擬內(nèi)存設(shè)備globalvar驅(qū)動(dòng)實(shí)現(xiàn)

1、實(shí)驗(yàn)三：虛擬內(nèi)存設(shè)備globalvar驅(qū)動(dòng)實(shí)現(xiàn)我們來(lái)假設(shè)另外一個(gè)非常簡(jiǎn)單的虛擬字符設(shè)備：這個(gè)設(shè)備中只有一個(gè)4個(gè)字節(jié)的全局變量intglobal_var，而這個(gè)設(shè)備的名字叫做“gobalvar”。對(duì)“gobalvar”設(shè)備的讀寫(xiě)等操作即是對(duì)其中全局變量global_var的操作。在homebookglobalvar下新建源文件myglobalvar.c如下：#include#include#include#include#defineMA

2、J_NUM154主設(shè)備號(hào)staticintglobal_var=0“globalvar“設(shè)備的全局變量staticssize_tglobalvar_read(structfilesize_tloff_t)staticssize_tglobalvar_write(structfileconstsize_tloff_t)structfile_operationsglobalvar_fops=read:globalvar_readwrite:

3、globalvar_writestaticint__initglobalvar_init(void)intret注冊(cè)設(shè)備驅(qū)動(dòng)ret=register_chrdev(MAJ_NUM“globalvar“if(ret)printk(“globalvarregisterfailure“)elseprintk(“globalvarregistersuccess“)returnretstaticvoid__exitglobalvar_exit(v

4、oid)注銷(xiāo)設(shè)備驅(qū)動(dòng)unregister_chrdev(MAJ_NUM“globalvar“)staticssize_tglobalvar_read(structfilefilpbufsize_tlenloff_toff)將global_var從內(nèi)核空間復(fù)制到用戶(hù)空間if(copy_to_user(bufclose(fd)elseprintf(“Deviceopenfailuren“)編譯上述文件：gcc–staticoglobalva