为什么以下代码不能调用find_task_by_id__include_entry_int_find_task_by_id_return_

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为什么以下代码不能调用find_task_by_id

来源: 互联网发布时间：2016-02-07

本文导语: #include #include #include void execname() { struct task_struct *my; my = find_task_by_id(getpid()); printf("%s",my->comm); } int main() { execname(); return 0; } | find_task_by_id 是个内核函数,你在用户空间没法调...

#include
#include
#include
void execname() {
struct task_struct *my;
my = find_task_by_id(getpid());
printf("%s",my->comm);
}

int main() {
execname();
return 0;
}

find_task_by_id

是个内核函数,你在用户空间没法调用.你不能这样直接使用它.

下边是别人写的,可以看看

#include
#include
#include
#include
#include

MODULE_LICENSE("GPL");
MODULE_AUTHOR("scutan");

static int find_read(char *buffer, char **buffer_location, off_t offset, int count, int *eof, void *data)
{
        struct task_struct *p;
        int pid;
        pid = current->pid;
        p = find_task_by_pid(pid);
        sprintf(buffer, "%dt%sn", p->pid, p->comm);
        return strlen(buffer);
}

static int __init find_init(void)
{
        struct proc_dir_entry *entry;
        entry = create_proc_entry("findpid", 0644, NULL);
        if (entry == 0)
        {
                printk(KERN_ERR "creat_proc_entry failedn");
                return -1;
        }
        entry->mode = S_IFREG | S_IRUGO;
        entry->size = 100;
        entry->owner = THIS_MODULE;
        entry->uid = 0;
        entry->gid = 0;
        entry->read_proc = find_read;
        return 0;
}

void __exit find_exit(void)
{
        remove_proc_entry("findpid", &proc_root);
}

module_init(find_init);
module_exit(find_exit);

Makefile
代码:
obj-m:=find.o
KERNELDIR:=/usr/src/linux

default:
        make -C $(KERNELDIR) M=$(shell pwd) modules
install:
        insmod find.ko
uninstall:
        rmmod find.ko
clean:
        rm -rf *.o *.mod.c *.ko

另外还有一个测试程序get.c
代码:
#include
#include
#include
#include
#include

int main()
{
        int fd;
        char buf[50];
        fd = open("/proc/findpid", O_RDONLY);
        if (fd