jQuery绑定方法的区别 - .bind() / .live() / .delegate() / .on()

1、打开标准输入设备
      代码路径：init/main.c  目前处于进程1的3特权级

void init(void)
{
	int pid,i;

	setup((void *) &drive_info);
	(void) open("/dev/tty0",O_RDWR,0);
	(void) dup(0);
	(void) dup(0);
	...
}

int sys_open(const char * filename,int flag,int mode)
{
	struct m_inode * inode;
	struct file * f;
	int i,fd;

	mode &= 0777 & ~current->umask;//暂时不考虑
	for(fd=0 ; fd<NR_OPEN ; fd++)//找到进程第一个空闲的文件指针
		if (!current->filp[fd])
			break;
	if (fd>=NR_OPEN)
		return -EINVAL;
	current->close_on_exec &= ~(1<<fd);//全部置0
	f=0+file_table;
	for (i=0 ; i<NR_FILE ; i++,f++)//找到了file_table第一个file结构体
		if (!f->f_count) break;
	if (i>=NR_FILE)
		return -EINVAL;
	(current->filp[fd]=f)->f_count++;//将进程1的filp[20]与file_table[64]挂接，并增加引用计数，f_count为1
	if ((i=open_namei(filename,flag,mode,&inode))<0) {
		current->filp[fd]=NULL;
		f->f_count=0;
		return i;
	}
	...
}

#define NR_OPEN 20
#define NR_FILE 64

int open_namei(const char * pathname, int flag, int mode,
	struct m_inode ** res_inode)
{
	const char * basename;
	int inr,dev,namelen;
	struct m_inode * dir, *inode;
	struct buffer_head * bh;
	struct dir_entry * de;

	if ((flag & O_TRUNC) && !(flag & O_ACCMODE))
		flag |= O_WRONLY;
	mode &= 0777 & ~current->umask;
	mode |= I_REGULAR;//暂时不考虑
	if (!(dir = dir_namei(pathname,&namelen,&basename)))//获取枝梢i节点,namelen为tty0的长度，basename指向tty0的第一个字母‘t‘
		return -ENOENT;
	if (!namelen) {			/* special case: ‘/usr/‘ etc */
		if (!(flag & (O_ACCMODE|O_CREAT|O_TRUNC))) {
			*res_inode=dir;
			return 0;
		}
		iput(dir);
		return -EISDIR;
	}
	bh = find_entry(&dir,basename,namelen,&de);//此时根据dev的i节点和tty0来查找tty0的目录项
        ...
}

static struct m_inode * dir_namei(const char * pathname,
	int * namelen, const char ** name)
{
	char c;
	const char * basename;
	struct m_inode * dir;

	if (!(dir = get_dir(pathname)))
		return NULL;
	basename = pathname;
	while ((c=get_fs_byte(pathname++)))
		if (c==‘/‘)
			basename=pathname;
	*namelen = pathname-basename-1;//得到tty0名字的长度
	*name = basename;//得到tty0中第一个‘t’字符的地址
	return dir;
}

static struct m_inode * get_dir(const char * pathname)
{
	char c;
	const char * thisname;
	struct m_inode * inode;
	struct buffer_head * bh;
	int namelen,inr,idev;
	struct dir_entry * de;

	if (!current->root || !current->root->i_count)
		panic("No root inode");
	if (!current->pwd || !current->pwd->i_count)
		panic("No cwd inode");
	if ((c=get_fs_byte(pathname))==‘/‘) {
		inode = current->root;//根i节点
		pathname++;//指向d
	} else if (c)
		inode = current->pwd;
	else
		return NULL;	/* empty name is bad */
	inode->i_count++;//根i节点i_count为5
	while (1) {
		thisname = pathname;
		if (!S_ISDIR(inode->i_mode) || !permission(inode,MAY_EXEC)) {
			iput(inode);//不执行
			return NULL;
		}
		for(namelen=0;(c=get_fs_byte(pathname++))&&(c!=‘/‘);namelen++)//如果遇到/或者字符串结尾就退出
			/* nothing */ ;
		if (!c)
			return inode;//第二次循环返回空了，执行到此，返回dev的i节点
		if (!(bh = find_entry(&inode,thisname,namelen,&de))) {//此时根据根i节点和dev来查找dev的目录项,此时thisname为dev,namelen为3
			iput(inode);
			return NULL;
		}
		inr = de->inode;//dev的i节点号
		idev = inode->i_dev;//虚拟盘，0x101
		brelse(bh);
		iput(inode);//根i节点i_count为4
		if (!(inode = iget(idev,inr)))//获取了dev的i节点(inode_table第二个结构体)，i_count为1
			return NULL;
	}
}

...
#define NAME_LEN 14
...
struct dir_entry {
	unsigned short inode;
	char name[NAME_LEN];
};

...
struct m_inode {
	unsigned short i_mode;
	unsigned short i_uid;
	unsigned long i_size;
	unsigned long i_mtime;
	unsigned char i_gid;
	unsigned char i_nlinks;
	unsigned short i_zone[9];
/* these are in memory also */
	struct task_struct * i_wait;
	unsigned long i_atime;
	unsigned long i_ctime;
	unsigned short i_dev;
	unsigned short i_num;
	unsigned short i_count;
	unsigned char i_lock;
	unsigned char i_dirt;
	unsigned char i_pipe;
	unsigned char i_mount;
	unsigned char i_seek;
	unsigned char i_update;
};
...

int open_namei(const char * pathname, int flag, int mode,
	struct m_inode ** res_inode)
{
	...
	bh = find_entry(&dir,basename,namelen,&de);
	...
	inr = de->inode;//tty0的i节点号
	dev = dir->i_dev;//0x101
	brelse(bh);
	iput(dir);//第二个inode_table的i_count为0
	if (flag & O_EXCL)
		return -EEXIST;//不执行
	if (!(inode=iget(dev,inr)))//得到了tty0的i节点，(inode_table第二个结构体)，i_count为1
		return -EACCES;
	if ((S_ISDIR(inode->i_mode) && (flag & O_ACCMODE)) ||
	    !permission(inode,ACC_MODE(flag))) {
		iput(inode);//不执行
		return -EPERM;
	}
	inode->i_atime = CURRENT_TIME;
	if (flag & O_TRUNC)
		truncate(inode);//不执行
	*res_inode = inode;
	return 0;
}

...
int sys_open(const char * filename,int flag,int mode)
{
	struct m_inode * inode;
	struct file * f;
	int i,fd;

	mode &= 0777 & ~current->umask;
	for(fd=0 ; fd<NR_OPEN ; fd++)
		if (!current->filp[fd])//找到进程第一个空闲的文件指针
			break;
	if (fd>=NR_OPEN)
		return -EINVAL;
	current->close_on_exec &= ~(1<<fd);//全部置0
	f=0+file_table;
	for (i=0 ; i<NR_FILE ; i++,f++)//找到了file_table第一个file结构体
		if (!f->f_count) break;
	if (i>=NR_FILE)
		return -EINVAL;
	(current->filp[fd]=f)->f_count++;//将进程1的filp[20]与file_table[64]挂接，并增加引用计数，f_count为1
	if ((i=open_namei(filename,flag,mode,&inode))<0) {
		current->filp[fd]=NULL;
		f->f_count=0;
		return i;
	}
/* ttys are somewhat special (ttyxx major==4, tty major==5) */
	if (S_ISCHR(inode->i_mode)) {//检查tty0文件的i节点属性，确定它是一个设备文件
		if (MAJOR(inode->i_zone[0])==4) {
			if (current->leader && current->tty<0) {
				current->tty = MINOR(inode->i_zone[0]);
				tty_table[current->tty].pgrp = current->pgrp;
			}
		} else if (MAJOR(inode->i_zone[0])==5)
			if (current->tty<0) {
				iput(inode);
				current->filp[fd]=NULL;
				f->f_count=0;
				return -EPERM;
			}
	}
/* Likewise with block-devices: check for floppy_change */
	if (S_ISBLK(inode->i_mode))//暂时不考虑
		check_disk_change(inode->i_zone[0]);
	f->f_mode = inode->i_mode;
	f->f_flags = flag;
	f->f_count = 1;
	f->f_inode = inode;
	f->f_pos = 0;
	return (fd);//fd为0
}
...

          至此进程1的current->filp[0]存放的file_table第一个元素地址，file_table第一个元素，又存放着inode的地址，f_count为1

2、打开标准输出、标准错误输出设备

          又返回了进程1的3特权级，接着执行init()

          代码路径：init/main.c

void init(void)
{
	int pid,i;

	setup((void *) &drive_info);
	(void) open("/dev/tty0",O_RDWR,0);
	(void) dup(0);
	(void) dup(0);
        ...
}

         代码路径：fs/fcntl.c

static int dupfd(unsigned int fd, unsigned int arg)//fd为0，arg为0
{
	if (fd >= NR_OPEN || !current->filp[fd])
		return -EBADF;
	if (arg >= NR_OPEN)
		return -EINVAL;
	while (arg < NR_OPEN)
		if (current->filp[arg])
			arg++;
		else
			break;//arg为1
	if (arg >= NR_OPEN)
		return -EMFILE;
	current->close_on_exec &= ~(1<<arg);//还是全部为0
	(current->filp[arg] = current->filp[fd])->f_count++;//0和1共同指向一个文件地址，并且f_count为2
	return arg;
}

jQuery绑定方法的区别 - .bind() / .live() / .delegate() / .on(),古老的榕树,5-wow.com