sysctl: Separate the binary sysctl logic into it's own file.

In preparation for more invasive cleanups separate the core
binary sysctl logic into it's own file.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

kernel/sysctl_binary.c

@@ -0,0 +1,185 @@
+#include <linux/stat.h>
+#include <linux/sysctl.h>
+#include "../fs/xfs/linux-2.6/xfs_sysctl.h"
+#include <linux/sunrpc/debug.h>
+#include <linux/string.h>
+#include <net/ip_vs.h>
+#include <linux/syscalls.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/fs.h>
+#include <linux/nsproxy.h>
+#include <linux/pid_namespace.h>
+#include <linux/file.h>
+#include <linux/ctype.h>
+#include <linux/smp_lock.h>
+
+static int deprecated_sysctl_warning(struct __sysctl_args *args);
+
+#ifdef CONFIG_SYSCTL_SYSCALL
+
+/* Perform the actual read/write of a sysctl table entry. */
+static int do_sysctl_strategy(struct ctl_table_root *root,
+			struct ctl_table *table,
+			void __user *oldval, size_t __user *oldlenp,
+			void __user *newval, size_t newlen)
+{
+	int op = 0, rc;
+
+	if (oldval)
+		op |= MAY_READ;
+	if (newval)
+		op |= MAY_WRITE;
+	if (sysctl_perm(root, table, op))
+		return -EPERM;
+
+	if (table->strategy) {
+		rc = table->strategy(table, oldval, oldlenp, newval, newlen);
+		if (rc < 0)
+			return rc;
+		if (rc > 0)
+			return 0;
+	}
+
+	/* If there is no strategy routine, or if the strategy returns
+	 * zero, proceed with automatic r/w */
+	if (table->data && table->maxlen) {
+		rc = sysctl_data(table, oldval, oldlenp, newval, newlen);
+		if (rc < 0)
+			return rc;
+	}
+	return 0;
+}
+
+static int parse_table(int __user *name, int nlen,
+		       void __user *oldval, size_t __user *oldlenp,
+		       void __user *newval, size_t newlen,
+		       struct ctl_table_root *root,
+		       struct ctl_table *table)
+{
+	int n;
+repeat:
+	if (!nlen)
+		return -ENOTDIR;
+	if (get_user(n, name))
+		return -EFAULT;
+	for ( ; table->ctl_name || table->procname; table++) {
+		if (!table->ctl_name)
+			continue;
+		if (n == table->ctl_name) {
+			int error;
+			if (table->child) {
+				if (sysctl_perm(root, table, MAY_EXEC))
+					return -EPERM;
+				name++;
+				nlen--;
+				table = table->child;
+				goto repeat;
+			}
+			error = do_sysctl_strategy(root, table,
+						   oldval, oldlenp,
+						   newval, newlen);
+			return error;
+		}
+	}
+	return -ENOTDIR;
+}
+
+int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *oldlenp,
+	       void __user *newval, size_t newlen)
+{
+	struct ctl_table_header *head;
+	int error = -ENOTDIR;
+
+	if (nlen <= 0 || nlen >= CTL_MAXNAME)
+		return -ENOTDIR;
+	if (oldval) {
+		int old_len;
+		if (!oldlenp || get_user(old_len, oldlenp))
+			return -EFAULT;
+	}
+
+	for (head = sysctl_head_next(NULL); head;
+			head = sysctl_head_next(head)) {
+		error = parse_table(name, nlen, oldval, oldlenp, 
+					newval, newlen,
+					head->root, head->ctl_table);
+		if (error != -ENOTDIR) {
+			sysctl_head_finish(head);
+			break;
+		}
+	}
+	return error;
+}
+
+SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)
+{
+	struct __sysctl_args tmp;
+	int error;
+
+	if (copy_from_user(&tmp, args, sizeof(tmp)))
+		return -EFAULT;
+
+	error = deprecated_sysctl_warning(&tmp);
+	if (error)
+		goto out;
+
+	lock_kernel();
+	error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
+			  tmp.newval, tmp.newlen);
+	unlock_kernel();
+out:
+	return error;
+}
+
+#else /* CONFIG_SYSCTL_SYSCALL */
+
+SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)
+{
+	struct __sysctl_args tmp;
+	int error;
+
+	if (copy_from_user(&tmp, args, sizeof(tmp)))
+		return -EFAULT;
+
+	error = deprecated_sysctl_warning(&tmp);
+
+	/* If no error reading the parameters then just -ENOSYS ... */
+	if (!error)
+		error = -ENOSYS;
+
+	return error;
+}
+
+#endif /* CONFIG_SYSCTL_SYSCALL */
+
+static int deprecated_sysctl_warning(struct __sysctl_args *args)
+{
+	static int msg_count;
+	int name[CTL_MAXNAME];
+	int i;
+
+	/* Check args->nlen. */
+	if (args->nlen < 0 || args->nlen > CTL_MAXNAME)
+		return -ENOTDIR;
+
+	/* Read in the sysctl name for better debug message logging */
+	for (i = 0; i < args->nlen; i++)
+		if (get_user(name[i], args->name + i))
+			return -EFAULT;
+
+	/* Ignore accesses to kernel.version */
+	if ((args->nlen == 2) && (name[0] == CTL_KERN) && (name[1] == KERN_VERSION))
+		return 0;
+
+	if (msg_count < 5) {
+		msg_count++;
+		printk(KERN_INFO
+			"warning: process `%s' used the deprecated sysctl "
+			"system call with ", current->comm);
+		for (i = 0; i < args->nlen; i++)
+			printk("%d.", name[i]);
+		printk("\n");
+	}
+	return 0;
+}