[PATCH] Add cloexec information to fdinfo

drepper
2011-06-10T04:08:41Z

There is one piece of information about a file descriptor which is
currently not visible from the outside: the close-on-exec flag. The
/proc/PID/fdinfo/* files have the mode information but this is
missing. Is the following patch acceptable?

What I don't know is whether the RCU locking is needed given that
real locks are taken. Someone with more knowledge could just
remove those two lines.

Signed-off-by: Ulrich Drepper <drepper@gmail.com>

base.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 14def99..bda3651 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1924,12 +1924,23 @@ static int proc_fd_info(struct inode *inode, struct path *path, char *info)
*path = file->f_path;
path_get(&file->f_path);
}
- if (info)
+ if (info) {
+ int cloexec;
+ struct fdtable *fdt;
+
+ rcu_read_lock();
+ fdt = files_fdtable(files);
+ cloexec = FD_ISSET(fd, fdt->close_on_exec);
+ rcu_read_unlock();
+
snprintf(info, PROC_FDINFO_MAX,
"pos:\t%lli\n"
- "flags:\t0%o\n",
+ "flags:\t0%o\n"
+ "cloexec: %d\n",
(long long) file->f_pos,
- file->f_flags);
+ file->f_flags,
+ cloexec);
+ }
spin_unlock(&files->file_lock);
put_files_struct(files);
return 0;