On Mon, Aug 03, 2020 at 08:30:59PM -0400, Joel Fernandes wrote:

On Mon, Aug 3, 2020 at 10:47 AM 'Kalesh Singh' via kernel-team kernel-team@android.com wrote:

...

Provides a per process hook for the acquisition of file descriptors, despite the method used to obtain the descriptor.

Hi, So apart from all of the comments received, I think it is hard to understand what the problem is, what the front-end looks like etc. Your commit message is 1 line only.

I do remember some of the challenges discussed before, but it would describe the problem in the commit message in detail and then discuss why this solution is fit. Please read submitting-patches.rst especially "2) Describe your changes".

thanks,

• Joel

Thanks for the advice Joel :)

...

Signed-off-by: Kalesh Singh kaleshsingh@google.com

Documentation/filesystems/vfs.rst | 5 +++++ fs/file.c | 3 +++ include/linux/fs.h | 1 + 3 files changed, 9 insertions(+)

diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index ed17771c212b..95b30142c8d9 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -1123,6 +1123,11 @@ otherwise noted. ``fadvise`` possibly called by the fadvise64() system call.

+``fd_install``

•   called by the VFS when a file descriptor is installed in the
  

•   process's file descriptor table, regardless how the file descriptor
  

•   was acquired -- be it via the open syscall, received over IPC, etc.
  

Note that the file operations are implemented by the specific filesystem in which the inode resides. When opening a device node (character or block special) most filesystems will call special diff --git a/fs/file.c b/fs/file.c index abb8b7081d7a..f5db8622b851 100644 --- a/fs/file.c +++ b/fs/file.c @@ -616,6 +616,9 @@ void __fd_install(struct files_struct *files, unsigned int fd, void fd_install(unsigned int fd, struct file *file) { __fd_install(current->files, fd, file);

•   if (file->f_op->fd_install)
  

•           file->f_op->fd_install(fd, file);
  

}

EXPORT_SYMBOL(fd_install); diff --git a/include/linux/fs.h b/include/linux/fs.h index f5abba86107d..b976fbe8c902 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1864,6 +1864,7 @@ struct file_operations { struct file *file_out, loff_t pos_out, loff_t len, unsigned int remap_flags); int (*fadvise)(struct file *, loff_t, loff_t, int);

•   void (*fd_install)(int, struct file *);
  

} __randomize_layout;

struct inode_operations {

2.28.0.163.g6104cc2f0b6-goog

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