Commit 1117f72e authored Aug 06, 2011 by Linus Torvalds

vfs: show O_CLOEXE bit properly in /proc/<pid>/fdinfo/<fd> files



The CLOEXE bit is magical, and for performance (and semantic) reasons we
don't actually maintain it in the file descriptor itself, but in a
separate bit array.  Which means that when we show f_flags, the CLOEXE
status is shown incorrectly: we show the status not as it is now, but as
it was when the file was opened.

Fix that by looking up the bit properly in the 'fdt->close_on_exec' bit
array.

Uli needs this in order to re-implement the pfiles program:

  "For normal file descriptors (not sockets) this was the last piece of
   information which wasn't available.  This is all part of my 'give
   Solaris users no reason to not switch' effort.  I intend to offer the
   code to the util-linux-ng maintainers."

Requested-by: Ulrich Drepper <drepper@akkadia.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent c2142704

fs/proc/base.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -1919,6 +1919,14 @@ static int proc_fd_info(struct inode inode, struct path path, char *info)
		spin_lock(&files->file_lock);
		file = fcheck_files(files, fd);
		if (file) {
		unsigned int f_flags;
		struct fdtable *fdt;

		fdt = files_fdtable(files);
		f_flags = file->f_flags & ~O_CLOEXEC;
		if (FD_ISSET(fd, fdt->close_on_exec))
		f_flags \|= O_CLOEXEC;

		if (path) {
		*path = file->f_path;
		path_get(&file->f_path);
		@@ -1928,7 +1936,7 @@ static int proc_fd_info(struct inode inode, struct path path, char *info)
		"pos:\t%lli\n"
		"flags:\t0%o\n",
		(long long) file->f_pos,
		file->f_flags);
		f_flags);
		spin_unlock(&files->file_lock);
		put_files_struct(files);
		return 0;

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