导出进程内核栈dump ps，跟踪僵尸进程

#include

#include

#include

#include

#include

#include

#include

struct dentry *dumpps_dir = NULL;

#define USER_BUF_PAGE 4096

static ssize_t pid_write(struct file *file, const char __user *ubuf,

                  size_t len, loff_t *offp)

{

    char *tmpbuf;

    pid_t upid;

    struct task_struct *task, *p;

    struct pid *pid = NULL;

    if (len == 0)

        return 0;

    if (len > USER_BUF_PAGE - 1) {

        pr_warn("expected <%d bytes pid file\n", USER_BUF_PAGE);

        return -E2BIG;

    }

    tmpbuf = memdup_user_nul(ubuf, len);

    if (IS_ERR(tmpbuf))

        return PTR_ERR(tmpbuf);

    pr_info("read %d bytes from userspace\n", (int)len);

    upid = simple_strtol(tmpbuf, NULL, 10);

    pr_info("write pid=%d\n", upid);

    kfree(tmpbuf);

    pid = find_get_pid(upid);

    task = get_pid_task(pid, PIDTYPE_TGID);

    for_each_thread(task, p)  {

        sched_show_task(p);

    }

    put_task_struct(task);

    put_pid(pid);

    *offp += len;

    return len;

}

static const struct file_operations pid_fops = {

    .owner = THIS_MODULE,

    .write = pid_write

};

static int __init dumpps_init(void)

{

    dumpps_dir = debugfs_create_dir("dumpps", NULL);

    debugfs_create_file("pid", S_IFREG | S_IRUGO, dumpps_dir, NULL, &pid_fops);

    return 0;

}

static void __exit dumpps_exit(void)

{

    if(dumpps_dir){

        debugfs_remove(dumpps_dir);

        dumpps_dir = NULL;

    }

}

module_init(dumpps_init);

module_exit(dumpps_exit);

MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("LiuZhongzhi");

MODULE_DESCRIPTION("Dump process stack");