[snip]
>
> Well I clearly goofed when I added the initial network namespace support
> for /proc/net. Currently things work but there are odd details visible
> to user space, even when we have a single network namespace.
>
> Since we do not cache proc_dir_entry dentries at the moment we can
> just modify ->lookup to return a different directory inode depending
> on the network namespace of the process looking at /proc/net, replacing
> the current technique of using a magic and fragile follow_link method.
>
> To accomplish that this patch:
> - introduces a shadow_proc method to allow different dentries to
> be returned from proc_lookup.
> - Removes the old /proc/net follow_link magic
> - Fixes a weakness in our not caching of proc generic dentries.
>
> As shadow_proc uses a task struct to decided which dentry to return we
> can go back later and fix the proc generic caching without modifying any code that
> uses the shadow_proc method.
>
> Signed-off-by: Eric W. Biederman <[email protected]>
Thanks, Eric.
Much better ('find /proc' works and so does 'ls ..'), but one
issue is still unsolved :(
I mentioned the program, that opens the directory and dumps the
content of the /proc/self/fd. Here it is (stupid but simple):
==== prog.c
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <asm/fcntl.h>
#include <unistd.h>
int main(int argc, char **argv)
{
int fd;
fd = open(argv[1], O_RDONLY|O_DIRECTORY);
if (fd == -1) {
perror("Can't open");
return 1;
}
system("ls -l /proc/self/fd");
return 0;
}
====
So. Here's the result of running this program:
# cd /proc/net/
# pwd
/proc/net
# ~/a.out .
total 0
lrwx------ 1 root root 64 Nov 27 13:27 0 -> /dev/pts/0
lrwx------ 1 root root 64 Nov 27 13:27 1 -> /dev/pts/0
lrwx------ 1 root root 64 Nov 27 13:27 2 -> /dev/pts/0
lr-x------ 1 root root 64 Nov 27 13:27 3 -> /proc/net (deleted)
lr-x------ 1 root root 64 Nov 27 13:27 4 -> /proc/4475/fd
# cd /proc
# pwd
/proc
# ~/a.out net
total 0
lrwx------ 1 root root 64 Nov 27 13:27 0 -> /dev/pts/0
lrwx------ 1 root root 64 Nov 27 13:27 1 -> /dev/pts/0
lrwx------ 1 root root 64 Nov 27 13:27 2 -> /dev/pts/0
lr-x------ 1 root root 64 Nov 27 13:27 3 -> /proc/net
lr-x------ 1 root root 64 Nov 27 13:27 4 -> /proc/4477/fd
# cd /proc/net/stat
# pwd
/proc/net/stat
# ~/a.out ..
total 0
lrwx------ 1 root root 64 Nov 27 13:29 0 -> /dev/pts/0
lrwx------ 1 root root 64 Nov 27 13:29 1 -> /dev/pts/0
lrwx------ 1 root root 64 Nov 27 13:29 2 -> /dev/pts/0
lr-x------ 1 root root 64 Nov 27 13:29 3 -> /proc/net (deleted)
lr-x------ 1 root root 64 Nov 27 13:29 4 -> /proc/4482/fd
# ~/a.out .
total 0
lrwx------ 1 root root 64 Nov 27 13:32 0 -> /dev/pts/0
lrwx------ 1 root root 64 Nov 27 13:32 1 -> /dev/pts/0
lrwx------ 1 root root 64 Nov 27 13:32 2 -> /dev/pts/0
lr-x------ 1 root root 64 Nov 27 13:32 3 -> /proc/net/stat
lr-x------ 1 root root 64 Nov 27 13:32 4 -> /proc/4488/fd
Bad thing is that . when cdir is /proc/net and .. when cdir is
anything under /proc/net (i.e. the /proc/net itself) is marked as "(deleted)".
[snip]
Thanks,
Pavel
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