linux/ipc/ipc_sysctl.c

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/*
* Copyright (C) 2007
*
* Author: Eric Biederman <ebiederm@xmision.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*/
#include <linux/module.h>
#include <linux/ipc.h>
#include <linux/nsproxy.h>
#include <linux/sysctl.h>
#include <linux/uaccess.h>
namespaces: move the IPC namespace under IPC_NS option Currently the IPC namespace management code is spread over the ipc/*.c files. I moved this code into ipc/namespace.c file which is compiled out when needed. The linux/ipc_namespace.h file is used to store the prototypes of the functions in namespace.c and the stubs for NAMESPACES=n case. This is done so, because the stub for copy_ipc_namespace requires the knowledge of the CLONE_NEWIPC flag, which is in sched.h. But the linux/ipc.h file itself in included into many many .c files via the sys.h->sem.h sequence so adding the sched.h into it will make all these .c depend on sched.h which is not that good. On the other hand the knowledge about the namespaces stuff is required in 4 .c files only. Besides, this patch compiles out some auxiliary functions from ipc/sem.c, msg.c and shm.c files. It turned out that moving these functions into namespaces.c is not that easy because they use many other calls and macros from the original file. Moving them would make this patch complicated. On the other hand all these functions can be consolidated, so I will send a separate patch doing this a bit later. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 13:18:22 +01:00
#include <linux/ipc_namespace.h>
#include <linux/msg.h>
#include "util.h"
static void *get_ipc(ctl_table *table)
{
char *which = table->data;
struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
return which;
}
/*
* Routine that is called when a tunable has successfully been changed by
* hand and it has a callback routine registered on the ipc namespace notifier
* chain: we don't want such tunables to be recomputed anymore upon memory
* add/remove or ipc namespace creation/removal.
* They can come back to a recomputable state by being set to a <0 value.
*/
static void tunable_set_callback(int val)
{
if (val >= 0)
unregister_ipcns_notifier(current->nsproxy->ipc_ns);
else {
/*
* Re-enable automatic recomputing only if not already
* enabled.
*/
recompute_msgmni(current->nsproxy->ipc_ns);
cond_register_ipcns_notifier(current->nsproxy->ipc_ns);
}
}
#ifdef CONFIG_PROC_FS
static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table ipc_table;
memcpy(&ipc_table, table, sizeof(ipc_table));
ipc_table.data = get_ipc(table);
return proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos);
}
static int proc_ipc_callback_dointvec(ctl_table *table, int write,
struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table ipc_table;
size_t lenp_bef = *lenp;
int rc;
memcpy(&ipc_table, table, sizeof(ipc_table));
ipc_table.data = get_ipc(table);
rc = proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos);
if (write && !rc && lenp_bef == *lenp)
tunable_set_callback(*((int *)(ipc_table.data)));
return rc;
}
static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table ipc_table;
memcpy(&ipc_table, table, sizeof(ipc_table));
ipc_table.data = get_ipc(table);
return proc_doulongvec_minmax(&ipc_table, write, filp, buffer,
lenp, ppos);
}
#else
#define proc_ipc_doulongvec_minmax NULL
#define proc_ipc_dointvec NULL
#define proc_ipc_callback_dointvec NULL
#endif
#ifdef CONFIG_SYSCTL_SYSCALL
/* The generic sysctl ipc data routine. */
static int sysctl_ipc_data(ctl_table *table, int __user *name, int nlen,
void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen)
{
size_t len;
void *data;
/* Get out of I don't have a variable */
if (!table->data || !table->maxlen)
return -ENOTDIR;
data = get_ipc(table);
if (!data)
return -ENOTDIR;
if (oldval && oldlenp) {
if (get_user(len, oldlenp))
return -EFAULT;
if (len) {
if (len > table->maxlen)
len = table->maxlen;
if (copy_to_user(oldval, data, len))
return -EFAULT;
if (put_user(len, oldlenp))
return -EFAULT;
}
}
if (newval && newlen) {
if (newlen > table->maxlen)
newlen = table->maxlen;
if (copy_from_user(data, newval, newlen))
return -EFAULT;
}
return 1;
}
static int sysctl_ipc_registered_data(ctl_table *table, int __user *name,
int nlen, void __user *oldval, size_t __user *oldlenp,
void __user *newval, size_t newlen)
{
int rc;
rc = sysctl_ipc_data(table, name, nlen, oldval, oldlenp, newval,
newlen);
if (newval && newlen && rc > 0) {
/*
* Tunable has successfully been changed from userland
*/
int *data = get_ipc(table);
tunable_set_callback(*data);
}
return rc;
}
#else
#define sysctl_ipc_data NULL
#define sysctl_ipc_registered_data NULL
#endif
static struct ctl_table ipc_kern_table[] = {
{
.ctl_name = KERN_SHMMAX,
.procname = "shmmax",
.data = &init_ipc_ns.shm_ctlmax,
.maxlen = sizeof (init_ipc_ns.shm_ctlmax),
.mode = 0644,
.proc_handler = proc_ipc_doulongvec_minmax,
.strategy = sysctl_ipc_data,
},
{
.ctl_name = KERN_SHMALL,
.procname = "shmall",
.data = &init_ipc_ns.shm_ctlall,
.maxlen = sizeof (init_ipc_ns.shm_ctlall),
.mode = 0644,
.proc_handler = proc_ipc_doulongvec_minmax,
.strategy = sysctl_ipc_data,
},
{
.ctl_name = KERN_SHMMNI,
.procname = "shmmni",
.data = &init_ipc_ns.shm_ctlmni,
.maxlen = sizeof (init_ipc_ns.shm_ctlmni),
.mode = 0644,
.proc_handler = proc_ipc_dointvec,
.strategy = sysctl_ipc_data,
},
{
.ctl_name = KERN_MSGMAX,
.procname = "msgmax",
.data = &init_ipc_ns.msg_ctlmax,
.maxlen = sizeof (init_ipc_ns.msg_ctlmax),
.mode = 0644,
.proc_handler = proc_ipc_dointvec,
.strategy = sysctl_ipc_data,
},
{
.ctl_name = KERN_MSGMNI,
.procname = "msgmni",
.data = &init_ipc_ns.msg_ctlmni,
.maxlen = sizeof (init_ipc_ns.msg_ctlmni),
.mode = 0644,
.proc_handler = proc_ipc_callback_dointvec,
.strategy = sysctl_ipc_registered_data,
},
{
.ctl_name = KERN_MSGMNB,
.procname = "msgmnb",
.data = &init_ipc_ns.msg_ctlmnb,
.maxlen = sizeof (init_ipc_ns.msg_ctlmnb),
.mode = 0644,
.proc_handler = proc_ipc_dointvec,
.strategy = sysctl_ipc_data,
},
{
.ctl_name = KERN_SEM,
.procname = "sem",
.data = &init_ipc_ns.sem_ctls,
.maxlen = 4*sizeof (int),
.mode = 0644,
.proc_handler = proc_ipc_dointvec,
.strategy = sysctl_ipc_data,
},
{}
};
static struct ctl_table ipc_root_table[] = {
{
.ctl_name = CTL_KERN,
.procname = "kernel",
.mode = 0555,
.child = ipc_kern_table,
},
{}
};
static int __init ipc_sysctl_init(void)
{
[PATCH] sysctl: remove insert_at_head from register_sysctl The semantic effect of insert_at_head is that it would allow new registered sysctl entries to override existing sysctl entries of the same name. Which is pain for caching and the proc interface never implemented. I have done an audit and discovered that none of the current users of register_sysctl care as (excpet for directories) they do not register duplicate sysctl entries. So this patch simply removes the support for overriding existing entries in the sys_sysctl interface since no one uses it or cares and it makes future enhancments harder. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Andi Kleen <ak@muc.de> Cc: Jens Axboe <axboe@kernel.dk> Cc: Corey Minyard <minyard@acm.org> Cc: Neil Brown <neilb@suse.de> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Jan Kara <jack@ucw.cz> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: David Chinner <dgc@sgi.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Patrick McHardy <kaber@trash.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-14 09:34:09 +01:00
register_sysctl_table(ipc_root_table);
return 0;
}
__initcall(ipc_sysctl_init);