-/* buffer size is one page but our output routines use some slack for overruns */
-#define PROC_BLOCK_SIZE (PAGE_SIZE - 1024)
-
-static ssize_t
-__proc_file_read(struct file *file, char __user *buf, size_t nbytes,
- loff_t *ppos)
-{
- struct inode * inode = file_inode(file);
- char *page;
- ssize_t retval=0;
- int eof=0;
- ssize_t n, count;
- char *start;
- struct proc_dir_entry * dp;
- unsigned long long pos;
-
- /*
- * Gaah, please just use "seq_file" instead. The legacy /proc
- * interfaces cut loff_t down to off_t for reads, and ignore
- * the offset entirely for writes..
- */
- pos = *ppos;
- if (pos > MAX_NON_LFS)
- return 0;
- if (nbytes > MAX_NON_LFS - pos)
- nbytes = MAX_NON_LFS - pos;
-
- dp = PDE(inode);
- if (!(page = (char*) __get_free_page(GFP_TEMPORARY)))
- return -ENOMEM;
-
- while ((nbytes > 0) && !eof) {
- count = min_t(size_t, PROC_BLOCK_SIZE, nbytes);
-
- start = NULL;
- if (dp->read_proc) {
- /*
- * How to be a proc read function
- * ------------------------------
- * Prototype:
- * int f(char *buffer, char **start, off_t offset,
- * int count, int *peof, void *dat)
- *
- * Assume that the buffer is "count" bytes in size.
- *
- * If you know you have supplied all the data you
- * have, set *peof.
- *
- * You have three ways to return data:
- * 0) Leave *start = NULL. (This is the default.)
- * Put the data of the requested offset at that
- * offset within the buffer. Return the number (n)
- * of bytes there are from the beginning of the
- * buffer up to the last byte of data. If the
- * number of supplied bytes (= n - offset) is
- * greater than zero and you didn't signal eof
- * and the reader is prepared to take more data
- * you will be called again with the requested
- * offset advanced by the number of bytes
- * absorbed. This interface is useful for files
- * no larger than the buffer.
- * 1) Set *start = an unsigned long value less than
- * the buffer address but greater than zero.
- * Put the data of the requested offset at the
- * beginning of the buffer. Return the number of
- * bytes of data placed there. If this number is
- * greater than zero and you didn't signal eof
- * and the reader is prepared to take more data
- * you will be called again with the requested
- * offset advanced by *start. This interface is
- * useful when you have a large file consisting
- * of a series of blocks which you want to count
- * and return as wholes.
- * (Hack by Paul.Russell@rustcorp.com.au)
- * 2) Set *start = an address within the buffer.
- * Put the data of the requested offset at *start.
- * Return the number of bytes of data placed there.
- * If this number is greater than zero and you
- * didn't signal eof and the reader is prepared to
- * take more data you will be called again with the
- * requested offset advanced by the number of bytes
- * absorbed.
- */
- n = dp->read_proc(page, &start, *ppos,
- count, &eof, dp->data);
- } else
- break;
-
- if (n == 0) /* end of file */
- break;
- if (n < 0) { /* error */
- if (retval == 0)
- retval = n;
- break;
- }
-
- if (start == NULL) {
- if (n > PAGE_SIZE) /* Apparent buffer overflow */
- n = PAGE_SIZE;
- n -= *ppos;
- if (n <= 0)
- break;
- if (n > count)
- n = count;
- start = page + *ppos;
- } else if (start < page) {
- if (n > PAGE_SIZE) /* Apparent buffer overflow */
- n = PAGE_SIZE;
- if (n > count) {
- /*
- * Don't reduce n because doing so might
- * cut off part of a data block.
- */
- pr_warn("proc_file_read: count exceeded\n");
- }
- } else /* start >= page */ {
- unsigned long startoff = (unsigned long)(start - page);
- if (n > (PAGE_SIZE - startoff)) /* buffer overflow? */
- n = PAGE_SIZE - startoff;
- if (n > count)
- n = count;
- }
-
- n -= copy_to_user(buf, start < page ? page : start, n);
- if (n == 0) {
- if (retval == 0)
- retval = -EFAULT;
- break;
- }
-
- *ppos += start < page ? (unsigned long)start : n;
- nbytes -= n;
- buf += n;
- retval += n;
- }
- free_page((unsigned long) page);
- return retval;
-}
-
-static ssize_t
-proc_file_read(struct file *file, char __user *buf, size_t nbytes,
- loff_t *ppos)
-{
- struct proc_dir_entry *pde = PDE(file_inode(file));
- ssize_t rv = -EIO;
-
- spin_lock(&pde->pde_unload_lock);
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
- return rv;
- }
- pde->pde_users++;
- spin_unlock(&pde->pde_unload_lock);
-
- rv = __proc_file_read(file, buf, nbytes, ppos);
-
- pde_users_dec(pde);
- return rv;
-}
-
-static ssize_t
-proc_file_write(struct file *file, const char __user *buffer,
- size_t count, loff_t *ppos)
-{
- struct proc_dir_entry *pde = PDE(file_inode(file));
- ssize_t rv = -EIO;
-
- if (pde->write_proc) {
- spin_lock(&pde->pde_unload_lock);
- if (!pde->proc_fops) {
- spin_unlock(&pde->pde_unload_lock);
- return rv;
- }
- pde->pde_users++;
- spin_unlock(&pde->pde_unload_lock);
-
- /* FIXME: does this routine need ppos? probably... */
- rv = pde->write_proc(file, buffer, count, pde->data);
- pde_users_dec(pde);
- }
- return rv;
-}
-
-
-static loff_t
-proc_file_lseek(struct file *file, loff_t offset, int orig)
-{
- loff_t retval = -EINVAL;
- switch (orig) {
- case 1:
- offset += file->f_pos;
- /* fallthrough */
- case 0:
- if (offset < 0 || offset > MAX_NON_LFS)
- break;
- file->f_pos = retval = offset;
- }
- return retval;
-}
-
-static const struct file_operations proc_file_operations = {
- .llseek = proc_file_lseek,
- .read = proc_file_read,
- .write = proc_file_write,
-};
-