From 8f19d472935c83d823fa4cf02bcc0a7b9952db30 Mon Sep 17 00:00:00 2001 From: Eric Biederman Date: Wed, 18 Feb 2009 14:48:16 -0800 Subject: seq_file: properly cope with pread Currently seq_read assumes that the offset passed to it is always the offset it passed to user space. In the case pread this assumption is broken and we do the wrong thing when presented with pread. To solve this I introduce an offset cache inside of struct seq_file so we know where our logical file position is. Then in seq_read if we try to read from another offset we reset our data structures and attempt to go to the offset user space wanted. [akpm@linux-foundation.org: restore FMODE_PWRITE] [pjt@google.com: seq_open needs its fmode opened up to take advantage of this] Signed-off-by: Eric Biederman Cc: Alexey Dobriyan Cc: Al Viro Cc: Paul Turner Cc: [2.6.25.x, 2.6.26.x, 2.6.27.x, 2.6.28.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/seq_file.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/seq_file.h') diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h index 40ea5058c2ec..f616f31576d7 100644 --- a/include/linux/seq_file.h +++ b/include/linux/seq_file.h @@ -19,6 +19,7 @@ struct seq_file { size_t from; size_t count; loff_t index; + loff_t read_pos; u64 version; struct mutex lock; const struct seq_operations *op; -- cgit v1.2.1