mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-06 02:24:14 +08:00
0f7fc9e4d0
This patch changes struct file to use struct path instead of having independent pointers to struct dentry and struct vfsmount, and converts all users of f_{dentry,vfsmnt} in fs/ to use f_path.{dentry,mnt}. Additionally, it adds two #define's to make the transition easier for users of the f_dentry and f_vfsmnt. Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
450 lines
9.6 KiB
C
450 lines
9.6 KiB
C
/*
|
|
* linux/fs/seq_file.c
|
|
*
|
|
* helper functions for making synthetic files from sequences of records.
|
|
* initial implementation -- AV, Oct 2001.
|
|
*/
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/module.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/slab.h>
|
|
|
|
#include <asm/uaccess.h>
|
|
#include <asm/page.h>
|
|
|
|
/**
|
|
* seq_open - initialize sequential file
|
|
* @file: file we initialize
|
|
* @op: method table describing the sequence
|
|
*
|
|
* seq_open() sets @file, associating it with a sequence described
|
|
* by @op. @op->start() sets the iterator up and returns the first
|
|
* element of sequence. @op->stop() shuts it down. @op->next()
|
|
* returns the next element of sequence. @op->show() prints element
|
|
* into the buffer. In case of error ->start() and ->next() return
|
|
* ERR_PTR(error). In the end of sequence they return %NULL. ->show()
|
|
* returns 0 in case of success and negative number in case of error.
|
|
*/
|
|
int seq_open(struct file *file, const struct seq_operations *op)
|
|
{
|
|
struct seq_file *p = file->private_data;
|
|
|
|
if (!p) {
|
|
p = kmalloc(sizeof(*p), GFP_KERNEL);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
file->private_data = p;
|
|
}
|
|
memset(p, 0, sizeof(*p));
|
|
mutex_init(&p->lock);
|
|
p->op = op;
|
|
|
|
/*
|
|
* Wrappers around seq_open(e.g. swaps_open) need to be
|
|
* aware of this. If they set f_version themselves, they
|
|
* should call seq_open first and then set f_version.
|
|
*/
|
|
file->f_version = 0;
|
|
|
|
/* SEQ files support lseek, but not pread/pwrite */
|
|
file->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(seq_open);
|
|
|
|
/**
|
|
* seq_read - ->read() method for sequential files.
|
|
* @file: the file to read from
|
|
* @buf: the buffer to read to
|
|
* @size: the maximum number of bytes to read
|
|
* @ppos: the current position in the file
|
|
*
|
|
* Ready-made ->f_op->read()
|
|
*/
|
|
ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
|
|
{
|
|
struct seq_file *m = (struct seq_file *)file->private_data;
|
|
size_t copied = 0;
|
|
loff_t pos;
|
|
size_t n;
|
|
void *p;
|
|
int err = 0;
|
|
|
|
mutex_lock(&m->lock);
|
|
/*
|
|
* seq_file->op->..m_start/m_stop/m_next may do special actions
|
|
* or optimisations based on the file->f_version, so we want to
|
|
* pass the file->f_version to those methods.
|
|
*
|
|
* seq_file->version is just copy of f_version, and seq_file
|
|
* methods can treat it simply as file version.
|
|
* It is copied in first and copied out after all operations.
|
|
* It is convenient to have it as part of structure to avoid the
|
|
* need of passing another argument to all the seq_file methods.
|
|
*/
|
|
m->version = file->f_version;
|
|
/* grab buffer if we didn't have one */
|
|
if (!m->buf) {
|
|
m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
|
|
if (!m->buf)
|
|
goto Enomem;
|
|
}
|
|
/* if not empty - flush it first */
|
|
if (m->count) {
|
|
n = min(m->count, size);
|
|
err = copy_to_user(buf, m->buf + m->from, n);
|
|
if (err)
|
|
goto Efault;
|
|
m->count -= n;
|
|
m->from += n;
|
|
size -= n;
|
|
buf += n;
|
|
copied += n;
|
|
if (!m->count)
|
|
m->index++;
|
|
if (!size)
|
|
goto Done;
|
|
}
|
|
/* we need at least one record in buffer */
|
|
while (1) {
|
|
pos = m->index;
|
|
p = m->op->start(m, &pos);
|
|
err = PTR_ERR(p);
|
|
if (!p || IS_ERR(p))
|
|
break;
|
|
err = m->op->show(m, p);
|
|
if (err)
|
|
break;
|
|
if (m->count < m->size)
|
|
goto Fill;
|
|
m->op->stop(m, p);
|
|
kfree(m->buf);
|
|
m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
|
|
if (!m->buf)
|
|
goto Enomem;
|
|
m->count = 0;
|
|
m->version = 0;
|
|
}
|
|
m->op->stop(m, p);
|
|
m->count = 0;
|
|
goto Done;
|
|
Fill:
|
|
/* they want more? let's try to get some more */
|
|
while (m->count < size) {
|
|
size_t offs = m->count;
|
|
loff_t next = pos;
|
|
p = m->op->next(m, p, &next);
|
|
if (!p || IS_ERR(p)) {
|
|
err = PTR_ERR(p);
|
|
break;
|
|
}
|
|
err = m->op->show(m, p);
|
|
if (err || m->count == m->size) {
|
|
m->count = offs;
|
|
break;
|
|
}
|
|
pos = next;
|
|
}
|
|
m->op->stop(m, p);
|
|
n = min(m->count, size);
|
|
err = copy_to_user(buf, m->buf, n);
|
|
if (err)
|
|
goto Efault;
|
|
copied += n;
|
|
m->count -= n;
|
|
if (m->count)
|
|
m->from = n;
|
|
else
|
|
pos++;
|
|
m->index = pos;
|
|
Done:
|
|
if (!copied)
|
|
copied = err;
|
|
else
|
|
*ppos += copied;
|
|
file->f_version = m->version;
|
|
mutex_unlock(&m->lock);
|
|
return copied;
|
|
Enomem:
|
|
err = -ENOMEM;
|
|
goto Done;
|
|
Efault:
|
|
err = -EFAULT;
|
|
goto Done;
|
|
}
|
|
EXPORT_SYMBOL(seq_read);
|
|
|
|
static int traverse(struct seq_file *m, loff_t offset)
|
|
{
|
|
loff_t pos = 0;
|
|
int error = 0;
|
|
void *p;
|
|
|
|
m->version = 0;
|
|
m->index = 0;
|
|
m->count = m->from = 0;
|
|
if (!offset)
|
|
return 0;
|
|
if (!m->buf) {
|
|
m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
|
|
if (!m->buf)
|
|
return -ENOMEM;
|
|
}
|
|
p = m->op->start(m, &m->index);
|
|
while (p) {
|
|
error = PTR_ERR(p);
|
|
if (IS_ERR(p))
|
|
break;
|
|
error = m->op->show(m, p);
|
|
if (error)
|
|
break;
|
|
if (m->count == m->size)
|
|
goto Eoverflow;
|
|
if (pos + m->count > offset) {
|
|
m->from = offset - pos;
|
|
m->count -= m->from;
|
|
break;
|
|
}
|
|
pos += m->count;
|
|
m->count = 0;
|
|
if (pos == offset) {
|
|
m->index++;
|
|
break;
|
|
}
|
|
p = m->op->next(m, p, &m->index);
|
|
}
|
|
m->op->stop(m, p);
|
|
return error;
|
|
|
|
Eoverflow:
|
|
m->op->stop(m, p);
|
|
kfree(m->buf);
|
|
m->buf = kmalloc(m->size <<= 1, GFP_KERNEL);
|
|
return !m->buf ? -ENOMEM : -EAGAIN;
|
|
}
|
|
|
|
/**
|
|
* seq_lseek - ->llseek() method for sequential files.
|
|
* @file: the file in question
|
|
* @offset: new position
|
|
* @origin: 0 for absolute, 1 for relative position
|
|
*
|
|
* Ready-made ->f_op->llseek()
|
|
*/
|
|
loff_t seq_lseek(struct file *file, loff_t offset, int origin)
|
|
{
|
|
struct seq_file *m = (struct seq_file *)file->private_data;
|
|
long long retval = -EINVAL;
|
|
|
|
mutex_lock(&m->lock);
|
|
m->version = file->f_version;
|
|
switch (origin) {
|
|
case 1:
|
|
offset += file->f_pos;
|
|
case 0:
|
|
if (offset < 0)
|
|
break;
|
|
retval = offset;
|
|
if (offset != file->f_pos) {
|
|
while ((retval=traverse(m, offset)) == -EAGAIN)
|
|
;
|
|
if (retval) {
|
|
/* with extreme prejudice... */
|
|
file->f_pos = 0;
|
|
m->version = 0;
|
|
m->index = 0;
|
|
m->count = 0;
|
|
} else {
|
|
retval = file->f_pos = offset;
|
|
}
|
|
}
|
|
}
|
|
mutex_unlock(&m->lock);
|
|
file->f_version = m->version;
|
|
return retval;
|
|
}
|
|
EXPORT_SYMBOL(seq_lseek);
|
|
|
|
/**
|
|
* seq_release - free the structures associated with sequential file.
|
|
* @file: file in question
|
|
* @inode: file->f_path.dentry->d_inode
|
|
*
|
|
* Frees the structures associated with sequential file; can be used
|
|
* as ->f_op->release() if you don't have private data to destroy.
|
|
*/
|
|
int seq_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct seq_file *m = (struct seq_file *)file->private_data;
|
|
kfree(m->buf);
|
|
kfree(m);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(seq_release);
|
|
|
|
/**
|
|
* seq_escape - print string into buffer, escaping some characters
|
|
* @m: target buffer
|
|
* @s: string
|
|
* @esc: set of characters that need escaping
|
|
*
|
|
* Puts string into buffer, replacing each occurrence of character from
|
|
* @esc with usual octal escape. Returns 0 in case of success, -1 - in
|
|
* case of overflow.
|
|
*/
|
|
int seq_escape(struct seq_file *m, const char *s, const char *esc)
|
|
{
|
|
char *end = m->buf + m->size;
|
|
char *p;
|
|
char c;
|
|
|
|
for (p = m->buf + m->count; (c = *s) != '\0' && p < end; s++) {
|
|
if (!strchr(esc, c)) {
|
|
*p++ = c;
|
|
continue;
|
|
}
|
|
if (p + 3 < end) {
|
|
*p++ = '\\';
|
|
*p++ = '0' + ((c & 0300) >> 6);
|
|
*p++ = '0' + ((c & 070) >> 3);
|
|
*p++ = '0' + (c & 07);
|
|
continue;
|
|
}
|
|
m->count = m->size;
|
|
return -1;
|
|
}
|
|
m->count = p - m->buf;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(seq_escape);
|
|
|
|
int seq_printf(struct seq_file *m, const char *f, ...)
|
|
{
|
|
va_list args;
|
|
int len;
|
|
|
|
if (m->count < m->size) {
|
|
va_start(args, f);
|
|
len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
|
|
va_end(args);
|
|
if (m->count + len < m->size) {
|
|
m->count += len;
|
|
return 0;
|
|
}
|
|
}
|
|
m->count = m->size;
|
|
return -1;
|
|
}
|
|
EXPORT_SYMBOL(seq_printf);
|
|
|
|
int seq_path(struct seq_file *m,
|
|
struct vfsmount *mnt, struct dentry *dentry,
|
|
char *esc)
|
|
{
|
|
if (m->count < m->size) {
|
|
char *s = m->buf + m->count;
|
|
char *p = d_path(dentry, mnt, s, m->size - m->count);
|
|
if (!IS_ERR(p)) {
|
|
while (s <= p) {
|
|
char c = *p++;
|
|
if (!c) {
|
|
p = m->buf + m->count;
|
|
m->count = s - m->buf;
|
|
return s - p;
|
|
} else if (!strchr(esc, c)) {
|
|
*s++ = c;
|
|
} else if (s + 4 > p) {
|
|
break;
|
|
} else {
|
|
*s++ = '\\';
|
|
*s++ = '0' + ((c & 0300) >> 6);
|
|
*s++ = '0' + ((c & 070) >> 3);
|
|
*s++ = '0' + (c & 07);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
m->count = m->size;
|
|
return -1;
|
|
}
|
|
EXPORT_SYMBOL(seq_path);
|
|
|
|
static void *single_start(struct seq_file *p, loff_t *pos)
|
|
{
|
|
return NULL + (*pos == 0);
|
|
}
|
|
|
|
static void *single_next(struct seq_file *p, void *v, loff_t *pos)
|
|
{
|
|
++*pos;
|
|
return NULL;
|
|
}
|
|
|
|
static void single_stop(struct seq_file *p, void *v)
|
|
{
|
|
}
|
|
|
|
int single_open(struct file *file, int (*show)(struct seq_file *, void *),
|
|
void *data)
|
|
{
|
|
struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL);
|
|
int res = -ENOMEM;
|
|
|
|
if (op) {
|
|
op->start = single_start;
|
|
op->next = single_next;
|
|
op->stop = single_stop;
|
|
op->show = show;
|
|
res = seq_open(file, op);
|
|
if (!res)
|
|
((struct seq_file *)file->private_data)->private = data;
|
|
else
|
|
kfree(op);
|
|
}
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(single_open);
|
|
|
|
int single_release(struct inode *inode, struct file *file)
|
|
{
|
|
const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
|
|
int res = seq_release(inode, file);
|
|
kfree(op);
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(single_release);
|
|
|
|
int seq_release_private(struct inode *inode, struct file *file)
|
|
{
|
|
struct seq_file *seq = file->private_data;
|
|
|
|
kfree(seq->private);
|
|
seq->private = NULL;
|
|
return seq_release(inode, file);
|
|
}
|
|
EXPORT_SYMBOL(seq_release_private);
|
|
|
|
int seq_putc(struct seq_file *m, char c)
|
|
{
|
|
if (m->count < m->size) {
|
|
m->buf[m->count++] = c;
|
|
return 0;
|
|
}
|
|
return -1;
|
|
}
|
|
EXPORT_SYMBOL(seq_putc);
|
|
|
|
int seq_puts(struct seq_file *m, const char *s)
|
|
{
|
|
int len = strlen(s);
|
|
if (m->count + len < m->size) {
|
|
memcpy(m->buf + m->count, s, len);
|
|
m->count += len;
|
|
return 0;
|
|
}
|
|
m->count = m->size;
|
|
return -1;
|
|
}
|
|
EXPORT_SYMBOL(seq_puts);
|