![Nadia Derbey](/assets/img/avatar_default.png)
Make msgmni not recomputed anymore upon ipc namespace creation / removal or memory add/remove, as soon as it has been set from userland. As soon as msgmni is explicitly set via procfs or sysctl(), the associated callback routine is unregistered from the ipc namespace notifier chain. Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Mingming Cao <cmm@us.ibm.com> Cc: Pierre Peiffer <pierre.peiffer@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
220 lines
5.1 KiB
C
220 lines
5.1 KiB
C
/*
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* Copyright (C) 2007
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*
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* Author: Eric Biederman <ebiederm@xmision.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*/
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#include <linux/module.h>
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#include <linux/ipc.h>
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#include <linux/nsproxy.h>
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#include <linux/sysctl.h>
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#include <linux/uaccess.h>
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#include <linux/ipc_namespace.h>
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static void *get_ipc(ctl_table *table)
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{
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char *which = table->data;
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struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
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which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
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return which;
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}
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#ifdef CONFIG_PROC_FS
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static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp,
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void __user *buffer, size_t *lenp, loff_t *ppos)
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{
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struct ctl_table ipc_table;
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memcpy(&ipc_table, table, sizeof(ipc_table));
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ipc_table.data = get_ipc(table);
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return proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos);
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}
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static int proc_ipc_callback_dointvec(ctl_table *table, int write,
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struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
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{
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size_t lenp_bef = *lenp;
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int rc;
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rc = proc_ipc_dointvec(table, write, filp, buffer, lenp, ppos);
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if (write && !rc && lenp_bef == *lenp)
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/*
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* Tunable has successfully been changed from userland:
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* disable its automatic recomputing.
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*/
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unregister_ipcns_notifier(current->nsproxy->ipc_ns);
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return rc;
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}
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static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
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struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
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{
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struct ctl_table ipc_table;
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memcpy(&ipc_table, table, sizeof(ipc_table));
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ipc_table.data = get_ipc(table);
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return proc_doulongvec_minmax(&ipc_table, write, filp, buffer,
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lenp, ppos);
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}
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#else
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#define proc_ipc_doulongvec_minmax NULL
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#define proc_ipc_dointvec NULL
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#define proc_ipc_callback_dointvec NULL
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#endif
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#ifdef CONFIG_SYSCTL_SYSCALL
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/* The generic sysctl ipc data routine. */
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static int sysctl_ipc_data(ctl_table *table, int __user *name, int nlen,
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void __user *oldval, size_t __user *oldlenp,
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void __user *newval, size_t newlen)
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{
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size_t len;
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void *data;
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/* Get out of I don't have a variable */
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if (!table->data || !table->maxlen)
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return -ENOTDIR;
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data = get_ipc(table);
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if (!data)
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return -ENOTDIR;
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if (oldval && oldlenp) {
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if (get_user(len, oldlenp))
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return -EFAULT;
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if (len) {
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if (len > table->maxlen)
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len = table->maxlen;
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if (copy_to_user(oldval, data, len))
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return -EFAULT;
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if (put_user(len, oldlenp))
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return -EFAULT;
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}
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}
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if (newval && newlen) {
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if (newlen > table->maxlen)
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newlen = table->maxlen;
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if (copy_from_user(data, newval, newlen))
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return -EFAULT;
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}
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return 1;
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}
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static int sysctl_ipc_registered_data(ctl_table *table, int __user *name,
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int nlen, void __user *oldval, size_t __user *oldlenp,
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void __user *newval, size_t newlen)
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{
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int rc;
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rc = sysctl_ipc_data(table, name, nlen, oldval, oldlenp, newval,
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newlen);
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if (newval && newlen && rc > 0)
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/*
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* Tunable has successfully been changed from userland:
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* disable its automatic recomputing.
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*/
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unregister_ipcns_notifier(current->nsproxy->ipc_ns);
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return rc;
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}
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#else
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#define sysctl_ipc_data NULL
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#define sysctl_ipc_registered_data NULL
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#endif
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static struct ctl_table ipc_kern_table[] = {
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{
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.ctl_name = KERN_SHMMAX,
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.procname = "shmmax",
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.data = &init_ipc_ns.shm_ctlmax,
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.maxlen = sizeof (init_ipc_ns.shm_ctlmax),
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.mode = 0644,
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.proc_handler = proc_ipc_doulongvec_minmax,
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.strategy = sysctl_ipc_data,
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},
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{
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.ctl_name = KERN_SHMALL,
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.procname = "shmall",
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.data = &init_ipc_ns.shm_ctlall,
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.maxlen = sizeof (init_ipc_ns.shm_ctlall),
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.mode = 0644,
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.proc_handler = proc_ipc_doulongvec_minmax,
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.strategy = sysctl_ipc_data,
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},
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{
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.ctl_name = KERN_SHMMNI,
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.procname = "shmmni",
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.data = &init_ipc_ns.shm_ctlmni,
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.maxlen = sizeof (init_ipc_ns.shm_ctlmni),
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.mode = 0644,
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.proc_handler = proc_ipc_dointvec,
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.strategy = sysctl_ipc_data,
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},
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{
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.ctl_name = KERN_MSGMAX,
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.procname = "msgmax",
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.data = &init_ipc_ns.msg_ctlmax,
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.maxlen = sizeof (init_ipc_ns.msg_ctlmax),
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.mode = 0644,
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.proc_handler = proc_ipc_dointvec,
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.strategy = sysctl_ipc_data,
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},
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{
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.ctl_name = KERN_MSGMNI,
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.procname = "msgmni",
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.data = &init_ipc_ns.msg_ctlmni,
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.maxlen = sizeof (init_ipc_ns.msg_ctlmni),
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.mode = 0644,
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.proc_handler = proc_ipc_callback_dointvec,
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.strategy = sysctl_ipc_registered_data,
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},
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{
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.ctl_name = KERN_MSGMNB,
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.procname = "msgmnb",
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.data = &init_ipc_ns.msg_ctlmnb,
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.maxlen = sizeof (init_ipc_ns.msg_ctlmnb),
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.mode = 0644,
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.proc_handler = proc_ipc_dointvec,
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.strategy = sysctl_ipc_data,
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},
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{
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.ctl_name = KERN_SEM,
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.procname = "sem",
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.data = &init_ipc_ns.sem_ctls,
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.maxlen = 4*sizeof (int),
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.mode = 0644,
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.proc_handler = proc_ipc_dointvec,
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.strategy = sysctl_ipc_data,
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},
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{}
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};
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static struct ctl_table ipc_root_table[] = {
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{
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.ctl_name = CTL_KERN,
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.procname = "kernel",
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.mode = 0555,
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.child = ipc_kern_table,
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},
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{}
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};
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static int __init ipc_sysctl_init(void)
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{
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register_sysctl_table(ipc_root_table);
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return 0;
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}
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__initcall(ipc_sysctl_init);
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