*/
file->f_version = 0;
- /* SEQ files support lseek, but not pread/pwrite */
- file->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
+ /*
+ * seq_files support lseek() and pread(). They do not implement
+ * write() at all, but we clear FMODE_PWRITE here for historical
+ * reasons.
+ *
+ * If a client of seq_files a) implements file.write() and b) wishes to
+ * support pwrite() then that client will need to implement its own
+ * file.open() which calls seq_open() and then sets FMODE_PWRITE.
+ */
+ file->f_mode &= ~FMODE_PWRITE;
return 0;
}
EXPORT_SYMBOL(seq_open);
+static int traverse(struct seq_file *m, loff_t offset)
+{
+ loff_t pos = 0, index;
+ int error = 0;
+ void *p;
+
+ m->version = 0;
+ index = 0;
+ m->count = m->from = 0;
+ if (!offset) {
+ m->index = index;
+ return 0;
+ }
+ if (!m->buf) {
+ m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
+ if (!m->buf)
+ return -ENOMEM;
+ }
+ p = m->op->start(m, &index);
+ while (p) {
+ error = PTR_ERR(p);
+ if (IS_ERR(p))
+ break;
+ error = m->op->show(m, p);
+ if (error < 0)
+ break;
+ if (unlikely(error)) {
+ error = 0;
+ m->count = 0;
+ }
+ if (m->count == m->size)
+ goto Eoverflow;
+ if (pos + m->count > offset) {
+ m->from = offset - pos;
+ m->count -= m->from;
+ m->index = index;
+ break;
+ }
+ pos += m->count;
+ m->count = 0;
+ if (pos == offset) {
+ index++;
+ m->index = index;
+ break;
+ }
+ p = m->op->next(m, p, &index);
+ }
+ m->op->stop(m, p);
+ m->index = index;
+ 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_read - ->read() method for sequential files.
* @file: the file to read from
int err = 0;
mutex_lock(&m->lock);
+
+ /* Don't assume *ppos is where we left it */
+ if (unlikely(*ppos != m->read_pos)) {
+ m->read_pos = *ppos;
+ while ((err = traverse(m, *ppos)) == -EAGAIN)
+ ;
+ if (err) {
+ /* With prejudice... */
+ m->read_pos = 0;
+ m->version = 0;
+ m->index = 0;
+ m->count = 0;
+ goto Done;
+ }
+ }
+
/*
* 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
Done:
if (!copied)
copied = err;
- else
+ else {
*ppos += copied;
+ m->read_pos += copied;
+ }
file->f_version = m->version;
mutex_unlock(&m->lock);
return copied;
}
EXPORT_SYMBOL(seq_read);
-static int traverse(struct seq_file *m, loff_t offset)
-{
- loff_t pos = 0, index;
- int error = 0;
- void *p;
-
- m->version = 0;
- index = 0;
- m->count = m->from = 0;
- if (!offset) {
- m->index = index;
- return 0;
- }
- if (!m->buf) {
- m->buf = kmalloc(m->size = PAGE_SIZE, GFP_KERNEL);
- if (!m->buf)
- return -ENOMEM;
- }
- p = m->op->start(m, &index);
- while (p) {
- error = PTR_ERR(p);
- if (IS_ERR(p))
- break;
- error = m->op->show(m, p);
- if (error < 0)
- break;
- if (unlikely(error)) {
- error = 0;
- m->count = 0;
- }
- if (m->count == m->size)
- goto Eoverflow;
- if (pos + m->count > offset) {
- m->from = offset - pos;
- m->count -= m->from;
- m->index = index;
- break;
- }
- pos += m->count;
- m->count = 0;
- if (pos == offset) {
- index++;
- m->index = index;
- break;
- }
- p = m->op->next(m, p, &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
if (offset < 0)
break;
retval = offset;
- if (offset != file->f_pos) {
+ if (offset != m->read_pos) {
while ((retval=traverse(m, offset)) == -EAGAIN)
;
if (retval) {
/* with extreme prejudice... */
file->f_pos = 0;
+ m->read_pos = 0;
m->version = 0;
m->index = 0;
m->count = 0;
} else {
+ m->read_pos = offset;
retval = file->f_pos = offset;
}
}
EXPORT_SYMBOL(seq_printf);
/**
- * mangle_path - mangle and copy path to buffer beginning
- * @s - buffer start
- * @p - beginning of path in above buffer
- * @esc - set of characters that need escaping
+ * mangle_path - mangle and copy path to buffer beginning
+ * @s: buffer start
+ * @p: beginning of path in above buffer
+ * @esc: set of characters that need escaping
*
* Copy the path from @p to @s, replacing each occurrence of character from
* @esc with usual octal escape.
}
return NULL;
}
-EXPORT_SYMBOL_GPL(mangle_path);
+EXPORT_SYMBOL(mangle_path);
-/*
- * return the absolute path of 'dentry' residing in mount 'mnt'.
+/**
+ * seq_path - seq_file interface to print a pathname
+ * @m: the seq_file handle
+ * @path: the struct path to print
+ * @esc: set of characters to escape in the output
+ *
+ * return the absolute path of 'path', as represented by the
+ * dentry / mnt pair in the path parameter.
*/
int seq_path(struct seq_file *m, struct path *path, char *esc)
{
return -1;
}
-int seq_bitmap(struct seq_file *m, unsigned long *bits, unsigned int nr_bits)
+int seq_bitmap(struct seq_file *m, const unsigned long *bits,
+ unsigned int nr_bits)
{
if (m->count < m->size) {
int len = bitmap_scnprintf(m->buf + m->count,