From: Stephen Mell <sub.atomic.fus...@gmail.com>
Currently, there is no userspace method to mount proc for a pid namespace other
than the current one. In light of the new namespace filedescriptors, this patch
adds a mount option to use the namespace represented by the specified
filedescriptor instead of the current pid namespace. This patch depends on
"proc: move proc mount options out of pid_namespace".
Signed-off-by: Stephen Mell <sub.atomic.fus...@gmail.com>
---
fs/proc/root.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 5a2b6ff..6a9a46d 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -39,10 +39,11 @@ static int proc_set_super(struct super_block *sb, void
*data)
}
enum {
- Opt_gid, Opt_hidepid, Opt_err,
+ Opt_nsfd, Opt_gid, Opt_hidepid, Opt_err,
};
static const match_table_t tokens = {
+ {Opt_nsfd, "nsfd=%u"},
{Opt_hidepid, "hidepid=%u"},
{Opt_gid, "gid=%u"},
{Opt_err, NULL},
@@ -53,6 +54,8 @@ static int proc_parse_options(char *options, struct
proc_sb_info *fsi)
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
+ struct proc_ns *ei;
+ struct file *file;
if (!options)
return 1;
@@ -65,6 +68,24 @@ static int proc_parse_options(char *options, struct
proc_sb_info *fsi)
args[0].to = args[0].from = NULL;
token = match_token(p, tokens, args);
switch (token) {
+ case Opt_nsfd:
+ if (match_int(&args[0], &option))
+ return 0;
+ file = proc_ns_fget(option);
+ if (IS_ERR(file)) {
+ pr_err("proc: nsfd value must refer to a pid
namespace.\n");
+ return 0;
+ }
+ ei = get_proc_ns(file_inode(file));
+ if (!(ei->ns_ops->type & CLONE_NEWPID)) {
+ pr_err("proc: nsfd value must refer to a pid
namespace.\n");
+ return 0;
+ }
+ if (fsi->ns)
+ put_pid_ns(fsi->ns);
+ fsi->ns = ei->ns;
+ get_pid_ns(fsi->ns);
+ break;
case Opt_gid:
if (match_int(&args[0], &option))
return 0;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
