706 lines
16 KiB
C
706 lines
16 KiB
C
/*
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* proc/fs/generic.c --- generic routines for the proc-fs
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*
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* This file contains generic proc-fs routines for handling
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* directories and files.
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*
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* Copyright (C) 1991, 1992 Linus Torvalds.
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* Copyright (C) 1997 Theodore Ts'o
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*/
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#include <linux/errno.h>
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#include <linux/time.h>
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#include <linux/proc_fs.h>
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#include <linux/stat.h>
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#include <linux/module.h>
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#include <linux/mount.h>
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#include <linux/smp_lock.h>
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#include <linux/init.h>
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#include <linux/idr.h>
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#include <linux/namei.h>
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#include <linux/bitops.h>
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#include <asm/uaccess.h>
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static ssize_t proc_file_read(struct file *file, char __user *buf,
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size_t nbytes, loff_t *ppos);
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static ssize_t proc_file_write(struct file *file, const char __user *buffer,
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size_t count, loff_t *ppos);
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static loff_t proc_file_lseek(struct file *, loff_t, int);
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int proc_match(int len, const char *name, struct proc_dir_entry *de)
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{
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if (de->namelen != len)
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return 0;
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return !memcmp(name, de->name, len);
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}
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static struct file_operations proc_file_operations = {
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.llseek = proc_file_lseek,
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.read = proc_file_read,
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.write = proc_file_write,
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};
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/* buffer size is one page but our output routines use some slack for overruns */
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#define PROC_BLOCK_SIZE (PAGE_SIZE - 1024)
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static ssize_t
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proc_file_read(struct file *file, char __user *buf, size_t nbytes,
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loff_t *ppos)
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{
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struct inode * inode = file->f_dentry->d_inode;
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char *page;
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ssize_t retval=0;
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int eof=0;
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ssize_t n, count;
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char *start;
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struct proc_dir_entry * dp;
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dp = PDE(inode);
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if (!(page = (char*) __get_free_page(GFP_KERNEL)))
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return -ENOMEM;
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while ((nbytes > 0) && !eof) {
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count = min_t(size_t, PROC_BLOCK_SIZE, nbytes);
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start = NULL;
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if (dp->get_info) {
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/* Handle old net routines */
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n = dp->get_info(page, &start, *ppos, count);
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if (n < count)
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eof = 1;
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} else if (dp->read_proc) {
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/*
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* How to be a proc read function
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* ------------------------------
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* Prototype:
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* int f(char *buffer, char **start, off_t offset,
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* int count, int *peof, void *dat)
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*
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* Assume that the buffer is "count" bytes in size.
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*
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* If you know you have supplied all the data you
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* have, set *peof.
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*
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* You have three ways to return data:
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* 0) Leave *start = NULL. (This is the default.)
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* Put the data of the requested offset at that
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* offset within the buffer. Return the number (n)
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* of bytes there are from the beginning of the
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* buffer up to the last byte of data. If the
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* number of supplied bytes (= n - offset) is
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* greater than zero and you didn't signal eof
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* and the reader is prepared to take more data
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* you will be called again with the requested
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* offset advanced by the number of bytes
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* absorbed. This interface is useful for files
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* no larger than the buffer.
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* 1) Set *start = an unsigned long value less than
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* the buffer address but greater than zero.
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* Put the data of the requested offset at the
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* beginning of the buffer. Return the number of
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* bytes of data placed there. If this number is
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* greater than zero and you didn't signal eof
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* and the reader is prepared to take more data
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* you will be called again with the requested
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* offset advanced by *start. This interface is
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* useful when you have a large file consisting
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* of a series of blocks which you want to count
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* and return as wholes.
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* (Hack by Paul.Russell@rustcorp.com.au)
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* 2) Set *start = an address within the buffer.
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* Put the data of the requested offset at *start.
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* Return the number of bytes of data placed there.
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* If this number is greater than zero and you
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* didn't signal eof and the reader is prepared to
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* take more data you will be called again with the
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* requested offset advanced by the number of bytes
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* absorbed.
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*/
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n = dp->read_proc(page, &start, *ppos,
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count, &eof, dp->data);
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} else
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break;
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if (n == 0) /* end of file */
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break;
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if (n < 0) { /* error */
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if (retval == 0)
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retval = n;
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break;
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}
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if (start == NULL) {
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if (n > PAGE_SIZE) {
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printk(KERN_ERR
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"proc_file_read: Apparent buffer overflow!\n");
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n = PAGE_SIZE;
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}
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n -= *ppos;
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if (n <= 0)
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break;
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if (n > count)
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n = count;
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start = page + *ppos;
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} else if (start < page) {
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if (n > PAGE_SIZE) {
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printk(KERN_ERR
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"proc_file_read: Apparent buffer overflow!\n");
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n = PAGE_SIZE;
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}
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if (n > count) {
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/*
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* Don't reduce n because doing so might
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* cut off part of a data block.
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*/
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printk(KERN_WARNING
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"proc_file_read: Read count exceeded\n");
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}
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} else /* start >= page */ {
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unsigned long startoff = (unsigned long)(start - page);
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if (n > (PAGE_SIZE - startoff)) {
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printk(KERN_ERR
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"proc_file_read: Apparent buffer overflow!\n");
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n = PAGE_SIZE - startoff;
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}
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if (n > count)
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n = count;
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}
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n -= copy_to_user(buf, start < page ? page : start, n);
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if (n == 0) {
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if (retval == 0)
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retval = -EFAULT;
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break;
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}
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*ppos += start < page ? (unsigned long)start : n;
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nbytes -= n;
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buf += n;
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retval += n;
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}
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free_page((unsigned long) page);
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return retval;
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}
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static ssize_t
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proc_file_write(struct file *file, const char __user *buffer,
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size_t count, loff_t *ppos)
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{
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struct inode *inode = file->f_dentry->d_inode;
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struct proc_dir_entry * dp;
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dp = PDE(inode);
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if (!dp->write_proc)
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return -EIO;
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/* FIXME: does this routine need ppos? probably... */
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return dp->write_proc(file, buffer, count, dp->data);
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}
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static loff_t
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proc_file_lseek(struct file *file, loff_t offset, int orig)
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{
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lock_kernel();
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switch (orig) {
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case 0:
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if (offset < 0)
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goto out;
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file->f_pos = offset;
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unlock_kernel();
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return(file->f_pos);
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case 1:
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if (offset + file->f_pos < 0)
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goto out;
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file->f_pos += offset;
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unlock_kernel();
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return(file->f_pos);
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case 2:
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goto out;
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default:
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goto out;
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}
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out:
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unlock_kernel();
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return -EINVAL;
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}
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static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
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{
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struct inode *inode = dentry->d_inode;
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struct proc_dir_entry *de = PDE(inode);
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int error;
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error = inode_change_ok(inode, iattr);
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if (error)
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goto out;
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error = inode_setattr(inode, iattr);
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if (error)
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goto out;
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de->uid = inode->i_uid;
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de->gid = inode->i_gid;
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de->mode = inode->i_mode;
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out:
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return error;
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}
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static struct inode_operations proc_file_inode_operations = {
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.setattr = proc_notify_change,
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};
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/*
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* This function parses a name such as "tty/driver/serial", and
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* returns the struct proc_dir_entry for "/proc/tty/driver", and
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* returns "serial" in residual.
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*/
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static int xlate_proc_name(const char *name,
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struct proc_dir_entry **ret, const char **residual)
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{
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const char *cp = name, *next;
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struct proc_dir_entry *de;
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int len;
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de = &proc_root;
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while (1) {
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next = strchr(cp, '/');
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if (!next)
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break;
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len = next - cp;
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for (de = de->subdir; de ; de = de->next) {
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if (proc_match(len, cp, de))
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break;
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}
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if (!de)
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return -ENOENT;
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cp += len + 1;
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}
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*residual = cp;
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*ret = de;
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return 0;
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}
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static DEFINE_IDR(proc_inum_idr);
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static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
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#define PROC_DYNAMIC_FIRST 0xF0000000UL
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/*
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* Return an inode number between PROC_DYNAMIC_FIRST and
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* 0xffffffff, or zero on failure.
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*/
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static unsigned int get_inode_number(void)
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{
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int i, inum = 0;
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int error;
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retry:
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if (idr_pre_get(&proc_inum_idr, GFP_KERNEL) == 0)
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return 0;
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spin_lock(&proc_inum_lock);
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error = idr_get_new(&proc_inum_idr, NULL, &i);
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spin_unlock(&proc_inum_lock);
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if (error == -EAGAIN)
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goto retry;
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else if (error)
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return 0;
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inum = (i & MAX_ID_MASK) + PROC_DYNAMIC_FIRST;
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/* inum will never be more than 0xf0ffffff, so no check
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* for overflow.
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*/
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return inum;
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}
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static void release_inode_number(unsigned int inum)
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{
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int id = (inum - PROC_DYNAMIC_FIRST) | ~MAX_ID_MASK;
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spin_lock(&proc_inum_lock);
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idr_remove(&proc_inum_idr, id);
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spin_unlock(&proc_inum_lock);
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}
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static int proc_follow_link(struct dentry *dentry, struct nameidata *nd)
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{
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nd_set_link(nd, PDE(dentry->d_inode)->data);
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return 0;
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}
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static struct inode_operations proc_link_inode_operations = {
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.readlink = generic_readlink,
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.follow_link = proc_follow_link,
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};
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/*
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* As some entries in /proc are volatile, we want to
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* get rid of unused dentries. This could be made
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* smarter: we could keep a "volatile" flag in the
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* inode to indicate which ones to keep.
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*/
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static int proc_delete_dentry(struct dentry * dentry)
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{
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return 1;
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}
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static struct dentry_operations proc_dentry_operations =
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{
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.d_delete = proc_delete_dentry,
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};
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/*
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* Don't create negative dentries here, return -ENOENT by hand
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* instead.
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*/
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struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
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{
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struct inode *inode = NULL;
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struct proc_dir_entry * de;
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int error = -ENOENT;
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lock_kernel();
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de = PDE(dir);
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if (de) {
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for (de = de->subdir; de ; de = de->next) {
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if (de->namelen != dentry->d_name.len)
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continue;
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if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
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unsigned int ino = de->low_ino;
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error = -EINVAL;
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inode = proc_get_inode(dir->i_sb, ino, de);
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break;
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}
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}
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}
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unlock_kernel();
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if (inode) {
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dentry->d_op = &proc_dentry_operations;
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d_add(dentry, inode);
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return NULL;
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}
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return ERR_PTR(error);
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}
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/*
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* This returns non-zero if at EOF, so that the /proc
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* root directory can use this and check if it should
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* continue with the <pid> entries..
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*
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* Note that the VFS-layer doesn't care about the return
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* value of the readdir() call, as long as it's non-negative
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* for success..
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*/
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int proc_readdir(struct file * filp,
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void * dirent, filldir_t filldir)
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{
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struct proc_dir_entry * de;
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unsigned int ino;
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int i;
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struct inode *inode = filp->f_dentry->d_inode;
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int ret = 0;
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lock_kernel();
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ino = inode->i_ino;
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de = PDE(inode);
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if (!de) {
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ret = -EINVAL;
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goto out;
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}
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i = filp->f_pos;
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switch (i) {
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case 0:
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if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
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goto out;
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i++;
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filp->f_pos++;
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/* fall through */
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case 1:
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if (filldir(dirent, "..", 2, i,
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parent_ino(filp->f_dentry),
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DT_DIR) < 0)
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goto out;
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i++;
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filp->f_pos++;
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/* fall through */
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default:
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de = de->subdir;
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i -= 2;
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for (;;) {
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if (!de) {
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ret = 1;
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goto out;
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}
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if (!i)
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break;
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de = de->next;
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i--;
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}
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do {
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if (filldir(dirent, de->name, de->namelen, filp->f_pos,
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de->low_ino, de->mode >> 12) < 0)
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goto out;
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filp->f_pos++;
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de = de->next;
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} while (de);
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}
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ret = 1;
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out: unlock_kernel();
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return ret;
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}
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/*
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* These are the generic /proc directory operations. They
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* use the in-memory "struct proc_dir_entry" tree to parse
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* the /proc directory.
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*/
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static struct file_operations proc_dir_operations = {
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.read = generic_read_dir,
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.readdir = proc_readdir,
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};
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/*
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* proc directories can do almost nothing..
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*/
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static struct inode_operations proc_dir_inode_operations = {
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.lookup = proc_lookup,
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.setattr = proc_notify_change,
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};
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static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
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{
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unsigned int i;
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i = get_inode_number();
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if (i == 0)
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return -EAGAIN;
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dp->low_ino = i;
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dp->next = dir->subdir;
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dp->parent = dir;
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dir->subdir = dp;
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if (S_ISDIR(dp->mode)) {
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if (dp->proc_iops == NULL) {
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dp->proc_fops = &proc_dir_operations;
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dp->proc_iops = &proc_dir_inode_operations;
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}
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dir->nlink++;
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} else if (S_ISLNK(dp->mode)) {
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if (dp->proc_iops == NULL)
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dp->proc_iops = &proc_link_inode_operations;
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} else if (S_ISREG(dp->mode)) {
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if (dp->proc_fops == NULL)
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dp->proc_fops = &proc_file_operations;
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if (dp->proc_iops == NULL)
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dp->proc_iops = &proc_file_inode_operations;
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}
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return 0;
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}
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/*
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* Kill an inode that got unregistered..
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*/
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static void proc_kill_inodes(struct proc_dir_entry *de)
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{
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struct list_head *p;
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struct super_block *sb = proc_mnt->mnt_sb;
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/*
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* Actually it's a partial revoke().
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*/
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file_list_lock();
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list_for_each(p, &sb->s_files) {
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struct file * filp = list_entry(p, struct file, f_list);
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struct dentry * dentry = filp->f_dentry;
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struct inode * inode;
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struct file_operations *fops;
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if (dentry->d_op != &proc_dentry_operations)
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continue;
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inode = dentry->d_inode;
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if (PDE(inode) != de)
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continue;
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fops = filp->f_op;
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filp->f_op = NULL;
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fops_put(fops);
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}
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file_list_unlock();
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}
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static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent,
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const char *name,
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mode_t mode,
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nlink_t nlink)
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{
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struct proc_dir_entry *ent = NULL;
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const char *fn = name;
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int len;
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/* make sure name is valid */
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if (!name || !strlen(name)) goto out;
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if (!(*parent) && xlate_proc_name(name, parent, &fn) != 0)
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goto out;
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/* At this point there must not be any '/' characters beyond *fn */
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if (strchr(fn, '/'))
|
|
goto out;
|
|
|
|
len = strlen(fn);
|
|
|
|
ent = kmalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
|
|
if (!ent) goto out;
|
|
|
|
memset(ent, 0, sizeof(struct proc_dir_entry));
|
|
memcpy(((char *) ent) + sizeof(struct proc_dir_entry), fn, len + 1);
|
|
ent->name = ((char *) ent) + sizeof(*ent);
|
|
ent->namelen = len;
|
|
ent->mode = mode;
|
|
ent->nlink = nlink;
|
|
out:
|
|
return ent;
|
|
}
|
|
|
|
struct proc_dir_entry *proc_symlink(const char *name,
|
|
struct proc_dir_entry *parent, const char *dest)
|
|
{
|
|
struct proc_dir_entry *ent;
|
|
|
|
ent = proc_create(&parent,name,
|
|
(S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
|
|
|
|
if (ent) {
|
|
ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
|
|
if (ent->data) {
|
|
strcpy((char*)ent->data,dest);
|
|
if (proc_register(parent, ent) < 0) {
|
|
kfree(ent->data);
|
|
kfree(ent);
|
|
ent = NULL;
|
|
}
|
|
} else {
|
|
kfree(ent);
|
|
ent = NULL;
|
|
}
|
|
}
|
|
return ent;
|
|
}
|
|
|
|
struct proc_dir_entry *proc_mkdir_mode(const char *name, mode_t mode,
|
|
struct proc_dir_entry *parent)
|
|
{
|
|
struct proc_dir_entry *ent;
|
|
|
|
ent = proc_create(&parent, name, S_IFDIR | mode, 2);
|
|
if (ent) {
|
|
ent->proc_fops = &proc_dir_operations;
|
|
ent->proc_iops = &proc_dir_inode_operations;
|
|
|
|
if (proc_register(parent, ent) < 0) {
|
|
kfree(ent);
|
|
ent = NULL;
|
|
}
|
|
}
|
|
return ent;
|
|
}
|
|
|
|
struct proc_dir_entry *proc_mkdir(const char *name,
|
|
struct proc_dir_entry *parent)
|
|
{
|
|
return proc_mkdir_mode(name, S_IRUGO | S_IXUGO, parent);
|
|
}
|
|
|
|
struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
|
|
struct proc_dir_entry *parent)
|
|
{
|
|
struct proc_dir_entry *ent;
|
|
nlink_t nlink;
|
|
|
|
if (S_ISDIR(mode)) {
|
|
if ((mode & S_IALLUGO) == 0)
|
|
mode |= S_IRUGO | S_IXUGO;
|
|
nlink = 2;
|
|
} else {
|
|
if ((mode & S_IFMT) == 0)
|
|
mode |= S_IFREG;
|
|
if ((mode & S_IALLUGO) == 0)
|
|
mode |= S_IRUGO;
|
|
nlink = 1;
|
|
}
|
|
|
|
ent = proc_create(&parent,name,mode,nlink);
|
|
if (ent) {
|
|
if (S_ISDIR(mode)) {
|
|
ent->proc_fops = &proc_dir_operations;
|
|
ent->proc_iops = &proc_dir_inode_operations;
|
|
}
|
|
if (proc_register(parent, ent) < 0) {
|
|
kfree(ent);
|
|
ent = NULL;
|
|
}
|
|
}
|
|
return ent;
|
|
}
|
|
|
|
void free_proc_entry(struct proc_dir_entry *de)
|
|
{
|
|
unsigned int ino = de->low_ino;
|
|
|
|
if (ino < PROC_DYNAMIC_FIRST)
|
|
return;
|
|
|
|
release_inode_number(ino);
|
|
|
|
if (S_ISLNK(de->mode) && de->data)
|
|
kfree(de->data);
|
|
kfree(de);
|
|
}
|
|
|
|
/*
|
|
* Remove a /proc entry and free it if it's not currently in use.
|
|
* If it is in use, we set the 'deleted' flag.
|
|
*/
|
|
void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
|
|
{
|
|
struct proc_dir_entry **p;
|
|
struct proc_dir_entry *de;
|
|
const char *fn = name;
|
|
int len;
|
|
|
|
if (!parent && xlate_proc_name(name, &parent, &fn) != 0)
|
|
goto out;
|
|
len = strlen(fn);
|
|
for (p = &parent->subdir; *p; p=&(*p)->next ) {
|
|
if (!proc_match(len, fn, *p))
|
|
continue;
|
|
de = *p;
|
|
*p = de->next;
|
|
de->next = NULL;
|
|
if (S_ISDIR(de->mode))
|
|
parent->nlink--;
|
|
proc_kill_inodes(de);
|
|
de->nlink = 0;
|
|
WARN_ON(de->subdir);
|
|
if (!atomic_read(&de->count))
|
|
free_proc_entry(de);
|
|
else {
|
|
de->deleted = 1;
|
|
printk("remove_proc_entry: %s/%s busy, count=%d\n",
|
|
parent->name, de->name, atomic_read(&de->count));
|
|
}
|
|
break;
|
|
}
|
|
out:
|
|
return;
|
|
}
|