vfs: seq_file: add helpers for data filling (f8439806) · Commits · 戴 / test

fs/seq_file.c

+39 −36

Original line number	Diff line number	Diff line
		@@ -429,20 +429,21 @@ EXPORT_SYMBOL(mangle_path);
		*/
		int seq_path(struct seq_file m, struct path path, char *esc)
		{
		if (m->count < m->size) {
		char *s = m->buf + m->count;
		char *p = d_path(path, s, m->size - m->count);
		char *buf;
		size_t size = seq_get_buf(m, &buf);
		int res = -1;

		if (size) {
		char *p = d_path(path, buf, size);
		if (!IS_ERR(p)) {
		s = mangle_path(s, p, esc);
		if (s) {
		p = m->buf + m->count;
		m->count = s - m->buf;
		return s - p;
		}
		char *end = mangle_path(buf, p, esc);
		if (end)
		res = end - buf;
		}
		}
		m->count = m->size;
		return -1;
		seq_commit(m, res);

		return res;
		}
		EXPORT_SYMBOL(seq_path);

		@@ -454,27 +455,28 @@ EXPORT_SYMBOL(seq_path);
		int seq_path_root(struct seq_file m, struct path path, struct path *root,
		char *esc)
		{
		int err = -ENAMETOOLONG;
		if (m->count < m->size) {
		char *s = m->buf + m->count;
		char *buf;
		size_t size = seq_get_buf(m, &buf);
		int res = -ENAMETOOLONG;

		if (size) {
		char *p;

		spin_lock(&dcache_lock);
		p = __d_path(path, root, s, m->size - m->count);
		p = __d_path(path, root, buf, size);
		spin_unlock(&dcache_lock);
		err = PTR_ERR(p);
		res = PTR_ERR(p);
		if (!IS_ERR(p)) {
		s = mangle_path(s, p, esc);
		if (s) {
		p = m->buf + m->count;
		m->count = s - m->buf;
		return 0;
		}
		err = -ENAMETOOLONG;
		char *end = mangle_path(buf, p, esc);
		if (end)
		res = end - buf;
		else
		res = -ENAMETOOLONG;
		}
		}
		m->count = m->size;
		return err;
		seq_commit(m, res);

		return res < 0 ? res : 0;
		}

		/*
		@@ -482,20 +484,21 @@ int seq_path_root(struct seq_file m, struct path path, struct path *root,
		*/
		int seq_dentry(struct seq_file m, struct dentry dentry, char *esc)
		{
		if (m->count < m->size) {
		char *s = m->buf + m->count;
		char *p = dentry_path(dentry, s, m->size - m->count);
		char *buf;
		size_t size = seq_get_buf(m, &buf);
		int res = -1;

		if (size) {
		char *p = dentry_path(dentry, buf, size);
		if (!IS_ERR(p)) {
		s = mangle_path(s, p, esc);
		if (s) {
		p = m->buf + m->count;
		m->count = s - m->buf;
		return s - p;
		char *end = mangle_path(buf, p, esc);
		if (end)
		res = end - buf;
		}
		}
		}
		m->count = m->size;
		return -1;
		seq_commit(m, res);

		return res;
		}

		int seq_bitmap(struct seq_file m, const unsigned long bits,

include/linux/seq_file.h

+38 −0

Original line number	Diff line number	Diff line
		@@ -35,6 +35,44 @@ struct seq_operations {

		#define SEQ_SKIP 1

		/**
		* seq_get_buf - get buffer to write arbitrary data to
		* @m: the seq_file handle
		* @bufp: the beginning of the buffer is stored here
		*
		* Return the number of bytes available in the buffer, or zero if
		* there's no space.
		*/
		static inline size_t seq_get_buf(struct seq_file m, char *bufp)
		{
		BUG_ON(m->count > m->size);
		if (m->count < m->size)
		*bufp = m->buf + m->count;
		else
		*bufp = NULL;

		return m->size - m->count;
		}

		/**
		* seq_commit - commit data to the buffer
		* @m: the seq_file handle
		* @num: the number of bytes to commit
		*
		* Commit @num bytes of data written to a buffer previously acquired
		* by seq_buf_get. To signal an error condition, or that the data
		* didn't fit in the available space, pass a negative @num value.
		*/
		static inline void seq_commit(struct seq_file *m, int num)
		{
		if (num < 0) {
		m->count = m->size;
		} else {
		BUG_ON(m->count + num > m->size);
		m->count += num;
		}
		}

		char mangle_path(char s, char p, char esc);
		int seq_open(struct file , const struct seq_operations );
		ssize_t seq_read(struct file , char __user , size_t, loff_t *);

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