namespaces: mqueue namespace: adapt sysctl

Largely inspired from ipc/ipc_sysctl.c.  This patch isolates the mqueue
sysctl stuff in its own file.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 116 insertions, 0 deletions

diff --git a/ipc/mq_sysctl.c b/ipc/mq_sysctl.c
new file mode 100644
index 000000000000..89f60ec8ee54
--- /dev/null
+++ b/ipc/mq_sysctl.c
@@ -0,0 +1,116 @@
+/*
+ *  Copyright (C) 2007 IBM Corporation
+ *
+ *  Author: Cedric Le Goater <clg@fr.ibm.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/nsproxy.h>
+#include <linux/ipc_namespace.h>
+#include <linux/sysctl.h>
+
+/*
+ * Define the ranges various user-specified maximum values can
+ * be set to.
+ */
+#define MIN_MSGMAX      1               /* min value for msg_max */
+#define MAX_MSGMAX      HARD_MSGMAX     /* max value for msg_max */
+#define MIN_MSGSIZEMAX  128             /* min value for msgsize_max */
+#define MAX_MSGSIZEMAX  (8192*128)      /* max value for msgsize_max */
+
+static void *get_mq(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;
+}
+
+#ifdef CONFIG_PROC_SYSCTL
+static int proc_mq_dointvec(ctl_table *table, int write, struct file *filp,
+        void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        struct ctl_table mq_table;
+        memcpy(&mq_table, table, sizeof(mq_table));
+        mq_table.data = get_mq(table);
+
+        return proc_dointvec(&mq_table, write, filp, buffer, lenp, ppos);
+}
+
+static int proc_mq_dointvec_minmax(ctl_table *table, int write,
+        struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        struct ctl_table mq_table;
+        memcpy(&mq_table, table, sizeof(mq_table));
+        mq_table.data = get_mq(table);
+
+        return proc_dointvec_minmax(&mq_table, write, filp, buffer,
+                                        lenp, ppos);
+}
+#else
+#define proc_mq_dointvec NULL
+#define proc_mq_dointvec_minmax NULL
+#endif
+
+static int msg_max_limit_min = MIN_MSGMAX;
+static int msg_max_limit_max = MAX_MSGMAX;
+
+static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
+static int msg_maxsize_limit_max = MAX_MSGSIZEMAX;
+
+static ctl_table mq_sysctls[] = {
+        {
+                .procname       = "queues_max",
+                .data           = &init_ipc_ns.mq_queues_max,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_mq_dointvec,
+        },
+        {
+                .procname       = "msg_max",
+                .data           = &init_ipc_ns.mq_msg_max,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_mq_dointvec_minmax,
+                .extra1         = &msg_max_limit_min,
+                .extra2         = &msg_max_limit_max,
+        },
+        {
+                .procname       = "msgsize_max",
+                .data           = &init_ipc_ns.mq_msgsize_max,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_mq_dointvec_minmax,
+                .extra1         = &msg_maxsize_limit_min,
+                .extra2         = &msg_maxsize_limit_max,
+        },
+        { .ctl_name = 0 }
+};
+
+static ctl_table mq_sysctl_dir[] = {
+        {
+                .procname       = "mqueue",
+                .mode           = 0555,
+                .child          = mq_sysctls,
+        },
+        { .ctl_name = 0 }
+};
+
+static ctl_table mq_sysctl_root[] = {
+        {
+                .ctl_name       = CTL_FS,
+                .procname       = "fs",
+                .mode           = 0555,
+                .child          = mq_sysctl_dir,
+        },
+        { .ctl_name = 0 }
+};
+
+struct ctl_table_header *mq_register_sysctl_table(void)
+{
+        return register_sysctl_table(mq_sysctl_root);
+}