98f842e675
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>
147 lines
2.8 KiB
C
147 lines
2.8 KiB
C
/*
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* linux/ipc/msgutil.c
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* Copyright (C) 1999, 2004 Manfred Spraul
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*
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* This file is released under GNU General Public Licence version 2 or
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* (at your option) any later version.
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*
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* See the file COPYING for more details.
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*/
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#include <linux/spinlock.h>
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#include <linux/init.h>
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#include <linux/security.h>
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#include <linux/slab.h>
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#include <linux/ipc.h>
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#include <linux/msg.h>
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#include <linux/ipc_namespace.h>
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#include <linux/utsname.h>
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#include <linux/proc_fs.h>
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#include <asm/uaccess.h>
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#include "util.h"
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DEFINE_SPINLOCK(mq_lock);
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/*
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* The next 2 defines are here bc this is the only file
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* compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
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* and not CONFIG_IPC_NS.
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*/
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struct ipc_namespace init_ipc_ns = {
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.count = ATOMIC_INIT(1),
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.user_ns = &init_user_ns,
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.proc_inum = PROC_IPC_INIT_INO,
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};
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atomic_t nr_ipc_ns = ATOMIC_INIT(1);
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struct msg_msgseg {
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struct msg_msgseg* next;
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/* the next part of the message follows immediately */
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};
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#define DATALEN_MSG (PAGE_SIZE-sizeof(struct msg_msg))
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#define DATALEN_SEG (PAGE_SIZE-sizeof(struct msg_msgseg))
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struct msg_msg *load_msg(const void __user *src, int len)
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{
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struct msg_msg *msg;
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struct msg_msgseg **pseg;
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int err;
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int alen;
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alen = len;
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if (alen > DATALEN_MSG)
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alen = DATALEN_MSG;
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msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
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if (msg == NULL)
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return ERR_PTR(-ENOMEM);
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msg->next = NULL;
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msg->security = NULL;
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if (copy_from_user(msg + 1, src, alen)) {
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err = -EFAULT;
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goto out_err;
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}
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len -= alen;
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src = ((char __user *)src) + alen;
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pseg = &msg->next;
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while (len > 0) {
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struct msg_msgseg *seg;
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alen = len;
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if (alen > DATALEN_SEG)
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alen = DATALEN_SEG;
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seg = kmalloc(sizeof(*seg) + alen,
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GFP_KERNEL);
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if (seg == NULL) {
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err = -ENOMEM;
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goto out_err;
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}
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*pseg = seg;
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seg->next = NULL;
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if (copy_from_user(seg + 1, src, alen)) {
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err = -EFAULT;
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goto out_err;
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}
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pseg = &seg->next;
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len -= alen;
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src = ((char __user *)src) + alen;
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}
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err = security_msg_msg_alloc(msg);
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if (err)
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goto out_err;
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return msg;
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out_err:
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free_msg(msg);
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return ERR_PTR(err);
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}
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int store_msg(void __user *dest, struct msg_msg *msg, int len)
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{
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int alen;
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struct msg_msgseg *seg;
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alen = len;
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if (alen > DATALEN_MSG)
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alen = DATALEN_MSG;
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if (copy_to_user(dest, msg + 1, alen))
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return -1;
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len -= alen;
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dest = ((char __user *)dest) + alen;
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seg = msg->next;
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while (len > 0) {
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alen = len;
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if (alen > DATALEN_SEG)
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alen = DATALEN_SEG;
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if (copy_to_user(dest, seg + 1, alen))
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return -1;
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len -= alen;
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dest = ((char __user *)dest) + alen;
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seg = seg->next;
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}
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return 0;
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}
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void free_msg(struct msg_msg *msg)
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{
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struct msg_msgseg *seg;
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security_msg_msg_free(msg);
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seg = msg->next;
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kfree(msg);
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while (seg != NULL) {
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struct msg_msgseg *tmp = seg->next;
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kfree(seg);
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seg = tmp;
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}
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}
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