linux-stable/init/version.c
Eric W. Biederman 98f842e675 proc: Usable inode numbers for the namespace file descriptors.
Assign a unique proc inode to each namespace, and use that
inode number to ensure we only allocate at most one proc
inode for every namespace in proc.

A single proc inode per namespace allows userspace to test
to see if two processes are in the same namespace.

This has been a long requested feature and only blocked because
a naive implementation would put the id in a global space and
would ultimately require having a namespace for the names of
namespaces, making migration and certain virtualization tricks
impossible.

We still don't have per superblock inode numbers for proc, which
appears necessary for application unaware checkpoint/restart and
migrations (if the application is using namespace file descriptors)
but that is now allowd by the design if it becomes important.

I have preallocated the ipc and uts initial proc inode numbers so
their structures can be statically initialized.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-11-20 04:19:49 -08:00

50 lines
1.2 KiB
C

/*
* linux/init/version.c
*
* Copyright (C) 1992 Theodore Ts'o
*
* May be freely distributed as part of Linux.
*/
#include <generated/compile.h>
#include <linux/module.h>
#include <linux/uts.h>
#include <linux/utsname.h>
#include <generated/utsrelease.h>
#include <linux/version.h>
#include <linux/proc_fs.h>
#ifndef CONFIG_KALLSYMS
#define version(a) Version_ ## a
#define version_string(a) version(a)
extern int version_string(LINUX_VERSION_CODE);
int version_string(LINUX_VERSION_CODE);
#endif
struct uts_namespace init_uts_ns = {
.kref = {
.refcount = ATOMIC_INIT(2),
},
.name = {
.sysname = UTS_SYSNAME,
.nodename = UTS_NODENAME,
.release = UTS_RELEASE,
.version = UTS_VERSION,
.machine = UTS_MACHINE,
.domainname = UTS_DOMAINNAME,
},
.user_ns = &init_user_ns,
.proc_inum = PROC_UTS_INIT_INO,
};
EXPORT_SYMBOL_GPL(init_uts_ns);
/* FIXED STRINGS! Don't touch! */
const char linux_banner[] =
"Linux version " UTS_RELEASE " (" LINUX_COMPILE_BY "@"
LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION "\n";
const char linux_proc_banner[] =
"%s version %s"
" (" LINUX_COMPILE_BY "@" LINUX_COMPILE_HOST ")"
" (" LINUX_COMPILER ") %s\n";