[PATCH] sysctl: move SYSV IPC sysctls to their own file

This is just a simple cleanup to keep kernel/sysctl.c from getting to crowded
with special cases, and by keeping all of the ipc logic to together it makes
the code a little more readable.

[gcoady.lk@gmail.com: build fix]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Grant Coady <gcoady.lk@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

init/Kconfig

@@ -125,6 +125,12 @@ config IPC_NS
 	  environments, to use ipc namespaces to provide different ipc
 	  objects for different servers.  If unsure, say N.
 
+config SYSVIPC_SYSCTL
+	bool
+	depends on SYSVIPC
+	depends on SYSCTL
+	default y
+
 config POSIX_MQUEUE
 	bool "POSIX Message Queues"
 	depends on NET && EXPERIMENTAL

ipc/Makefile

@@ -4,6 +4,7 @@
 
 obj-$(CONFIG_SYSVIPC_COMPAT) += compat.o
 obj-$(CONFIG_SYSVIPC) += util.o msgutil.o msg.o sem.o shm.o
+obj-$(CONFIG_SYSVIPC_SYSCTL) += ipc_sysctl.o
 obj_mq-$(CONFIG_COMPAT) += compat_mq.o
 obj-$(CONFIG_POSIX_MQUEUE) += mqueue.o msgutil.o $(obj_mq-y)
 

ipc/ipc_sysctl.c

@@ -0,0 +1,183 @@
+/*
+ *  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>
+
+#ifdef CONFIG_IPC_NS
+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;
+}
+#else
+#define get_ipc(T) ((T)->data)
+#endif
+
+#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_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
+#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;
+}
+#else
+#define sysctl_ipc_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_dointvec,
+		.strategy	= sysctl_ipc_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)
+{
+	register_sysctl_table(ipc_root_table, 0);
+	return 0;
+}
+
+__initcall(ipc_sysctl_init);