[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>

2 files changed, 184 insertions, 0 deletions

diff --git a/ipc/Makefile b/ipc/Makefile
index 0a6d626cd794..b93bba6652f1 100644
--- a/ipc/Makefile
+++ b/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)
 
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
new file mode 100644
index 000000000000..2c17d83b9093
--- /dev/null
+++ b/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);