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authorMiklos Szeredi <mszeredi@suse.cz>2009-09-21 16:48:36 +0400
committerAl Viro <viro@zeniv.linux.org.uk>2009-09-24 15:47:35 +0400
commitf84398068d9c2babe41500504ef247ae07081857 (patch)
tree7306df97a7ee62f314f4db152fb2afceff156988 /include/linux/seq_file.h
parentf9098980ffea9c749622ff8ddf3b6d5831902a46 (diff)
downloadlinux-f84398068d9c2babe41500504ef247ae07081857.tar.xz
vfs: seq_file: add helpers for data filling
Add two helpers that allow access to the seq_file's own buffer, but hide the internal details of seq_files. This allows easier implementation of special purpose filling functions. It also cleans up some existing functions which duplicated the seq_file logic. Make these inline functions in seq_file.h, as suggested by Al. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/seq_file.h')
-rw-r--r--include/linux/seq_file.h38
1 files changed, 38 insertions, 0 deletions
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 0c6a86b79596..8366d8f12e53 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -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 *);