内核模块创建在proc文件系统上建立_ps文件.遍例进程内核链表task_struct.将遍例结果存入缓冲区.影射到/proc/_ps文件中.用户态的程序去读取 这个文件.打印显示 当前进程的的pid,ppid 和进程名.
#include
#include
#include
#include
#include
MODULE_LICENSE("GPL");
MODULE_AUTHOR("mq110");
static int ps_read(char *page, char **start, off_t offset,int count, int *eof, void *data)
{
static char buf[1024*8]={0};
char tmp[128];
struct task_struct *p;
if(offset >0)
return 0;
memset(buf,0,sizeof(buf));
read_lock(&tasklist_lock);
for_each_process(p) //遍例内核进程链表.
{
sprintf(tmp,"%d\t\t%d\t\t\t%s\n",p->pid,p->parent->pid,p->comm);
strcat(buf,tmp);
memset(tmp,0,sizeof(tmp));
}
read_unlock(&tasklist_lock);
*start=buf;
return strlen(buf);
}
static __init int ps_init(void)
{
struct proc_dir_entry *entry;
entry = create_proc_entry("_ps", 0444, &proc_root); //建立/proc/_ps文件.
if(entry == 0)
{
printk(KERN_ERR "create_proc_entry failed!\n");
return -1;
}
entry->mode = S_IFREG | 0444;
entry->size = 0;
entry->read_proc = ps_read;
return 0;
}
static __exit void ps_cleanup(void)
{
remove_proc_entry("_ps", &proc_root);
}
module_init(ps_init);
module_exit(ps_cleanup);
以下是Makefile. TARGET改名成程序名就OK了.
TARGET = 006
obj-m := $(TARGET).o
KERNELDIR=/lib/modules/`uname -r`/build
PWD=`pwd`
default :
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
install :
insmod $(TARGET).ko
uninstall :
rmmod $(TARGET).ko
clean :
rm -rf *.o *.mod.c *.ko
#include
#include
int main()
{
FILE *fp;
char buf[1024];
fp=fopen("/proc/_ps","r");
if(fp==NULL)
{
perror("fopen");
return -1;
}
printf("pid\t\tppid\t\t\tcommand\n");
while(!feof(fp))
{
if(fgets(buf,sizeof(buf),fp)!=NULL)
printf("%s",buf);
}
fclose(fp);
return 0;
}
make ;make install 之后 编译用户态程序.
