inode.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

/* $Id: inode.c,v 1.15 2001/11/12 09:43:39 davem Exp $
 * openpromfs.c: /proc/openprom handling routines
 *
 * Copyright (C) 1996-1999 Jakub Jelinek  ([e-mail])
 * Copyright (C) 1998      Eddie C. Dost  ([e-mail])
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/openprom_fs.h>
#include <linux/locks.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>

#include <asm/openprom.h>
#include <asm/oplib.h>
#include <asm/uaccess.h>

#define ALIASES_NNODES 64

typedef struct {
	u16	parent;
	u16	next;
	u16	child;
	u16	first_prop;
	u32	node;
} openpromfs_node;

typedef struct {
#define OPP_STRING	0x10
#define OPP_STRINGLIST	0x20
#define OPP_BINARY	0x40
#define OPP_HEXSTRING	0x80
#define OPP_DIRTY	0x01
#define OPP_QUOTED	0x02
#define OPP_NOTQUOTED	0x04
#define OPP_ASCIIZ	0x08
	u32	flag;
	u32	alloclen;
	u32	len;
	char	*value;
	char	name[8];
} openprom_property;

static openpromfs_node *nodes = NULL;
static int alloced = 0;
static u16 last_node = 0;
static u16 first_prop = 0;
static u16 options = 0xffff;
static u16 aliases = 0xffff;
static int aliases_nodes = 0;
static char *alias_names [ALIASES_NNODES];

#define OPENPROM_ROOT_INO	16
#define OPENPROM_FIRST_INO	OPENPROM_ROOT_INO
#define NODE(ino) nodes[ino - OPENPROM_FIRST_INO]
#define NODE2INO(node) (node + OPENPROM_FIRST_INO)
#define NODEP2INO(no) (no + OPENPROM_FIRST_INO + last_node)

static int openpromfs_create (struct inode *, struct dentry *, int);
static int openpromfs_readdir(struct file *, void *, filldir_t);
static struct dentry *openpromfs_lookup(struct inode *, struct dentry *dentry);
static int openpromfs_unlink (struct inode *, struct dentry *dentry);

static ssize_t nodenum_read(struct file *file, char *buf,
			    size_t count, loff_t *ppos)
{
	struct inode *inode = file->f_dentry->d_inode;
	char buffer[10];
	
	if (count < 0 || !inode->u.generic_ip)
		return -EINVAL;
	sprintf (buffer, "%8.8x\n", (u32)(long)(inode->u.generic_ip));
	if (file->f_pos >= 9)
		return 0;
	if (count > 9 - file->f_pos)
		count = 9 - file->f_pos;
	copy_to_user(buf, buffer + file->f_pos, count);
	file->f_pos += count;
	return count;
}

static ssize_t property_read(struct file *filp, char *buf,
			     size_t count, loff_t *ppos)
{
	struct inode *inode = filp->f_dentry->d_inode;
	int i, j, k;
	u32 node;
	char *p, *s;
	u32 *q;
	openprom_property *op;
	char buffer[64];
	
	if (filp->f_pos >= 0xffffff)
		return -EINVAL;
	if (!filp->private_data) {
		node = nodes[(u16)((long)inode->u.generic_ip)].node;
		i = ((u32)(long)inode->u.generic_ip) >> 16;
		if ((u16)((long)inode->u.generic_ip) == aliases) {
			if (i >= aliases_nodes)
				p = 0;
			else
				p = alias_names [i];
		} else
			for (p = prom_firstprop (node, buffer);
			     i && p && *p;
			     p = prom_nextprop (node, p, buffer), i--)
				/* nothing */ ;
		if (!p || !*p)
			return -EIO;
		i = prom_getproplen (node, p);
		if (i < 0) {
			if ((u16)((long)inode->u.generic_ip) == aliases)
				i = 0;
			else
				return -EIO;
		}
		k = i;
		if (i < 64) i = 64;
		filp->private_data = kmalloc (sizeof (openprom_property)
					      + (j = strlen (p)) + 2 * i,
					      GFP_KERNEL);
		if (!filp->private_data)
			return -ENOMEM;
		op = (openprom_property *)filp->private_data;
		op->flag = 0;
		op->alloclen = 2 * i;
		strcpy (op->name, p);
		op->value = (char *)(((unsigned long)(op->name + j + 4)) & ~3);
		op->len = k;
		if (k && prom_getproperty (node, p, op->value, i) < 0)
			return -EIO;
		op->value [k] = 0;
		if (k) {
			for (s = 0, p = op->value; p < op->value + k; p++) {
				if ((*p >= ' ' && *p <= '~') || *p == '\n') {
					op->flag |= OPP_STRING;
					s = p;
					continue;
				}
				if (p > op->value && !*p && s == p - 1) {
					if (p < op->value + k - 1)
						op->flag |= OPP_STRINGLIST;
					else
						op->flag |= OPP_ASCIIZ;
					continue;
				}
				if (k == 1 && !*p) {
					op->flag |= (OPP_STRING|OPP_ASCIIZ);
					break;
				}
				op->flag &= ~(OPP_STRING|OPP_STRINGLIST);
				if (k & 3)
					op->flag |= OPP_HEXSTRING;
				else
					op->flag |= OPP_BINARY;
				break;
			}
			if (op->flag & OPP_STRINGLIST)
				op->flag &= ~(OPP_STRING);
			if (op->flag & OPP_ASCIIZ)
				op->len--;
		}
	} else
		op = (openprom_property *)filp->private_data;
	if (!count || !(op->len || (op->flag & OPP_ASCIIZ)))
		return 0;
	if (op->flag & OPP_STRINGLIST) {
		for (k = 0, p = op->value; p < op->value + op->len; p++)
			if (!*p)
				k++;
		i = op->len + 4 * k + 3;
	} else if (op->flag & OPP_STRING) {
		i = op->len + 3;
	} else if (op->flag & OPP_BINARY) {
		i = (op->len * 9) >> 2;
	} else {
		i = (op->len << 1) + 1;
	}
	k = filp->f_pos;
	if (k >= i) return 0;
	if (count > i - k) count = i - k;
	if (op->flag & OPP_STRING) {
		if (!k) {
			__put_user('\'', buf);
			k++;
			count--;
		}

		if (k + count >= i - 2)
			j = i - 2 - k;
		else
			j = count;

		if (j >= 0) {
			copy_to_user(buf + k - filp->f_pos,
				     op->value + k - 1, j);
			count -= j;
			k += j;
		}

		if (count)
			__put_user('\'', &buf [k++ - filp->f_pos]);
		if (count > 1)
			__put_user('\n', &buf [k++ - filp->f_pos]);

	} else if (op->flag & OPP_STRINGLIST) {
		char *tmp;

		tmp = kmalloc (i, GFP_KERNEL);
		if (!tmp)
			return -ENOMEM;

		s = tmp;
		*s++ = '\'';
		for (p = op->value; p < op->value + op->len; p++) {
			if (!*p) {
				strcpy(s, "' + '");
				s += 5;
				continue;
			}
			*s++ = *p;
		}
		strcpy(s, "'\n");

		copy_to_user(buf, tmp + k, count);

		kfree(tmp);
		k += count;

	} else if (op->flag & OPP_BINARY) {
		char buffer[10];
		u32 *first, *last;
		int first_off, last_cnt;

		first = ((u32 *)op->value) + k / 9;
		first_off = k % 9;
		last = ((u32 *)op->value) + (k + count - 1) / 9;
		last_cnt = (k + count) % 9;
		if (!last_cnt) last_cnt = 9;

		if (first == last) {
			sprintf (buffer, "%08x.", *first);
			copy_to_user (buf, buffer + first_off, last_cnt - first_off);
			buf += last_cnt - first_off;
		} else {		
			for (q = first; q <= last; q++) {
				sprintf (buffer, "%08x.", *q);
				if (q == first) {
					copy_to_user (buf, buffer + first_off,
						      9 - first_off);
					buf += 9 - first_off;
				} else if (q == last) {
					copy_to_user (buf, buffer, last_cnt);
					buf += last_cnt;
				} else {
					copy_to_user (buf, buffer, 9);
					buf += 9;
				}
			}
		}

		if (last == (u32 *)(op->value + op->len - 4) && last_cnt == 9)
			__put_user('\n', (buf - 1));

		k += count;

	} else if (op->flag & OPP_HEXSTRING) {
		char buffer[2];

		if ((k < i - 1) && (k & 1)) {
			sprintf (buffer, "%02x", *(op->value + (k >> 1)));
			__put_user(buffer[1], &buf[k++ - filp->f_pos]);
			count--;
		}

		for (; (count > 1) && (k < i - 1); k += 2) {
			sprintf (buffer, "%02x", *(op->value + (k >> 1)));
			copy_to_user (buf + k - filp->f_pos, buffer, 2);
			count -= 2;
		}

		if (count && (k < i - 1)) {
			sprintf (buffer, "%02x", *(op->value + (k >> 1)));
			__put_user(buffer[0], &buf[k++ - filp->f_pos]);
			count--;
		}

		if (count)
			__put_user('\n', &buf [k++ - filp->f_pos]);
	}
	count = k - filp->f_pos;
	filp->f_pos = k;
	return count;
}

static ssize_t property_write(struct file *filp, const char *buf,
			      size_t count, loff_t *ppos)
{
	int i, j, k;
	char *p;
	u32 *q;
	void *b;
	openprom_property *op;
	
	if (filp->f_pos >= 0xffffff)
		return -EINVAL;
	if (!filp->private_data) {
		i = property_read (filp, NULL, 0, 0);
		if (i)
			return i;
	}
	k = filp->f_pos;
	op = (openprom_property *)filp->private_data;
	if (!(op->flag & OPP_STRING)) {
		u32 *first, *last;
		int first_off, last_cnt;
		u32 mask, mask2;
		char tmp [9];
		int forcelen = 0;
		
		j = k % 9;
		for (i = 0; i < count; i++, j++) {
			if (j == 9) j = 0;
			if (!j) {
				char ctmp;
				__get_user(ctmp, &buf[i]);
				if (ctmp != '.') {
					if (ctmp != '\n') {
						if (op->flag & OPP_BINARY)
							return -EINVAL;
						else
							goto write_try_string;
					} else {
						count = i + 1;
						forcelen = 1;
						break;
					}
				}
			} else {
				char ctmp;
				__get_user(ctmp, &buf[i]);
				if (ctmp < '0' || 
				    (ctmp > '9' && ctmp < 'A') ||
				    (ctmp > 'F' && ctmp < 'a') ||
				    ctmp > 'f') {
					if (op->flag & OPP_BINARY)
						return -EINVAL;
					else
						goto write_try_string;
				}
			}
		}
		op->flag |= OPP_BINARY;
		tmp [8] = 0;
		i = ((count + k + 8) / 9) << 2;
		if (op->alloclen <= i) {
			b = kmalloc (sizeof (openprom_property) + 2 * i,
				     GFP_KERNEL);
			if (!b)
				return -ENOMEM;
			memcpy (b, filp->private_data,
				sizeof (openprom_property)
				+ strlen (op->name) + op->alloclen);
			memset (((char *)b) + sizeof (openprom_property)
				+ strlen (op->name) + op->alloclen, 
				0, 2 * i - op->alloclen);
			op = (openprom_property *)b;
			op->alloclen = 2*i;
			b = filp->private_data;
			filp->private_data = (void *)op;
			kfree (b);
		}
		first = ((u32 *)op->value) + (k / 9);
		first_off = k % 9;
		last = (u32 *)(op->value + i);
		last_cnt = (k + count) % 9;
		if (first + 1 == last) {
			memset (tmp, '0', 8);
			copy_from_user (tmp + first_off, buf,
					(count + first_off > 8) ? 8 - first_off : count);
			mask = 0xffffffff;
			mask2 = 0xffffffff;
			for (j = 0; j < first_off; j++)
				mask >>= 1;
			for (j = 8 - count - first_off; j > 0; j--)
				mask2 <<= 1;
			mask &= mask2;
			if (mask) {
				*first &= ~mask;
				*first |= simple_strtoul (tmp, 0, 16);
				op->flag |= OPP_DIRTY;
			}
		} else {
			op->flag |= OPP_DIRTY;
			for (q = first; q < last; q++) {
				if (q == first) {
					if (first_off < 8) {
						memset (tmp, '0', 8);
						copy_from_user (tmp + first_off, buf,
								8 - first_off);
						mask = 0xffffffff;
						for (j = 0; j < first_off; j++)
							mask >>= 1;
						*q &= ~mask;
						*q |= simple_strtoul (tmp,0,16);
					}
					buf += 9;
				} else if ((q == last - 1) && last_cnt
					   && (last_cnt < 8)) {
					memset (tmp, '0', 8);
					copy_from_user (tmp, buf, last_cnt);
					mask = 0xffffffff;
					for (j = 0; j < 8 - last_cnt; j++)
						mask <<= 1;
					*q &= ~mask;
					*q |= simple_strtoul (tmp, 0, 16);
					buf += last_cnt;
				} else {
					char tchars[17]; /* XXX yuck... */

					copy_from_user(tchars, buf, 16);
					*q = simple_strtoul (tchars, 0, 16);
					buf += 9;
				}
			}
		}
		if (!forcelen) {
			if (op->len < i)
				op->len = i;
		} else
			op->len = i;
		filp->f_pos += count;
	}
write_try_string:
	if (!(op->flag & OPP_BINARY)) {
		if (!(op->flag & (OPP_QUOTED | OPP_NOTQUOTED))) {
			char ctmp;

			/* No way, if somebody starts writing from the middle, 
			 * we don't know whether he uses quotes around or not 
			 */
			if (k > 0)
				return -EINVAL;
			__get_user(ctmp, buf);
			if (ctmp == '\'') {
				op->flag |= OPP_QUOTED;
				buf++;
				count--;
				filp->f_pos++;
				if (!count) {
					op->flag |= OPP_STRING;
					return 1;
				}
			} else
				op->flag |= OPP_NOTQUOTED;
		}
		op->flag |= OPP_STRING;
		if (op->alloclen <= count + filp->f_pos) {
			b = kmalloc (sizeof (openprom_property)
				     + 2 * (count + filp->f_pos), GFP_KERNEL);
			if (!b)
				return -ENOMEM;
			memcpy (b, filp->private_data,
				sizeof (openprom_property)
				+ strlen (op->name) + op->alloclen);
			memset (((char *)b) + sizeof (openprom_property)
				+ strlen (op->name) + op->alloclen, 
				0, 2*(count - filp->f_pos) - op->alloclen);
			op = (openprom_property *)b;
			op->alloclen = 2*(count + filp->f_pos);
			b = filp->private_data;
			filp->private_data = (void *)op;
			kfree (b);
		}
		p = op->value + filp->f_pos - ((op->flag & OPP_QUOTED) ? 1 : 0);
		copy_from_user (p, buf, count);
		op->flag |= OPP_DIRTY;
		for (i = 0; i < count; i++, p++)
			if (*p == '\n') {
				*p = 0;
				break;
			}
		if (i < count) {
			op->len = p - op->value;
			filp->f_pos += i + 1;
			if ((p > op->value) && (op->flag & OPP_QUOTED)
			    && (*(p - 1) == '\''))
				op->len--;
		} else {
			if (p - op->value > op->len)
				op->len = p - op->value;
			filp->f_pos += count;
		}
	}
	return filp->f_pos - k;
}

int property_release (struct inode *inode, struct file *filp)
{
	openprom_property *op = (openprom_property *)filp->private_data;
	unsigned long flags;
	int error;
	u32 node;
	
	if (!op)
		return 0;
	lock_kernel();
	node = nodes[(u16)((long)inode->u.generic_ip)].node;
	if ((u16)((long)inode->u.generic_ip) == aliases) {
		if ((op->flag & OPP_DIRTY) && (op->flag & OPP_STRING)) {
			char *p = op->name;
			int i = (op->value - op->name) - strlen (op->name) - 1;
			op->value [op->len] = 0;
			*(op->value - 1) = ' ';
			if (i) {
				for (p = op->value - i - 2; p >= op->name; p--)
					p[i] = *p;
				p = op->name + i;
			}
			memcpy (p - 8, "nvalias ", 8);
			prom_feval (p - 8);
		}
	} else if (op->flag & OPP_DIRTY) {
		if (op->flag & OPP_STRING) {
			op->value [op->len] = 0;