/* *  linux/fs/proc/fd.c * *  Copyright (C) 1991, 1992 Linus Torvalds * *  proc fd directory handling functions */#include <asm/segment.h>#include <linux/errno.h>#include <linux/sched.h>#include <linux/proc_fs.h>#include <linux/stat.h>static int proc_readfd(struct inode *, struct file *, void *, filldir_t);static int proc_lookupfd(struct inode *,const char *,int,struct inode **);static struct file_operations proc_fd_operations = {	NULL,			/* lseek - default */	NULL,			/* read - bad */	NULL,			/* write - bad */	proc_readfd,		/* readdir */	NULL,			/* select - default */	NULL,			/* ioctl - default */	NULL,			/* mmap */	NULL,			/* no special open code */	NULL,			/* no special release code */	NULL			/* can't fsync */};/* * proc directories can do almost nothing.. */struct inode_operations proc_fd_inode_operations = {	&proc_fd_operations,	/* default base directory file-ops */	NULL,			/* create */	proc_lookupfd,		/* lookup */	NULL,			/* link */	NULL,			/* unlink */	NULL,			/* symlink */	NULL,			/* mkdir */	NULL,			/* rmdir */	NULL,			/* mknod */	NULL,			/* rename */	NULL,			/* readlink */	NULL,			/* follow_link */	NULL,			/* readpage */	NULL,			/* writepage */	NULL,			/* bmap */	NULL,			/* truncate */	NULL			/* permission */};static int proc_lookupfd(struct inode * dir, const char * name, int len,	struct inode ** result){	unsigned int ino, pid, fd, c;	struct task_struct * p;	struct super_block * sb;	int i;	*result = NULL;	ino = dir->i_ino;	pid = ino >> 16;	ino &= 0x0000ffff;	if (!dir)		return -ENOENT;	sb = dir->i_sb;	if (!pid || ino != PROC_PID_FD || !S_ISDIR(dir->i_mode)) {		iput(dir);		return -ENOENT;	}	if (!len || (name[0] == '.' && (len == 1 ||	    (name[1] == '.' && len == 2)))) {		if (len < 2) {			*result = dir;			return 0;		}		if (!(*result = proc_get_inode(sb, (pid << 16)+PROC_PID_INO, &proc_pid))) {			iput(dir);			return -ENOENT;		}		iput(dir);		return 0;	}	iput(dir);	fd = 0;	while (len-- > 0) {		c = *name - '0';		name++;		if (c > 9) {			fd = 0xfffff;			break;		}		fd *= 10;		fd += c;		if (fd & 0xffff0000) {			fd = 0xfffff;			break;		}	}	for (i = 0 ; i < NR_TASKS ; i++)		if ((p = task[i]) && p->pid == pid)			break;	if (!pid || i >= NR_TASKS)		return -ENOENT;	if (fd >= NR_OPEN || !p->files || !p->files->fd[fd]		|| !p->files->fd[fd]->f_inode)		return -ENOENT;	ino = (pid << 16) + (PROC_PID_FD_DIR << 8) + fd;	if (!(*result = proc_get_inode(sb, ino, NULL)))		return -ENOENT;	return 0;}#define NUMBUF 10static int proc_readfd(struct inode * inode, struct file * filp,	void * dirent, filldir_t filldir){	char buf[NUMBUF];	int task_nr;	struct task_struct * p;	unsigned int fd, pid, ino;	unsigned long i,j;	if (!inode || !S_ISDIR(inode->i_mode))		return -EBADF;	ino = inode->i_ino;	pid = ino >> 16;	ino &= 0x0000ffff;	if (ino != PROC_PID_FD)		return 0;	for (fd = filp->f_pos; fd < 2; fd++, filp->f_pos++) {		unsigned long ino = inode->i_ino;		if (fd)			ino = (ino & 0xffff0000) | PROC_PID_INO;		if (filldir(dirent, "..", fd+1, fd, ino) < 0)			return 0;	}	task_nr = 1;	for (;;) {		if ((p = task[task_nr]) && p->pid == pid)			break;		if (++task_nr >= NR_TASKS)			return 0;	}	for (fd -= 2 ; fd < NR_OPEN; fd++, filp->f_pos++) {		if (!p->files)			break;		if (!p->files->fd[fd] || !p->files->fd[fd]->f_inode)			continue;		j = NUMBUF;		i = fd;		do {			j--;			buf[j] = '0' + (i % 10);			i /= 10;		} while (i);		ino = (pid << 16) + (PROC_PID_FD_DIR << 8) + fd;		if (filldir(dirent, buf+j, NUMBUF-j, fd+2, ino) < 0)			break;		/* filldir() might have slept, so we must re-validate "p" */		if (p != task[task_nr] || p->pid != pid)			break;	}	return 0;}