Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / kernel / utsname_sysctl.c

diff --git a/kernel/kernel/utsname_sysctl.c b/kernel/kernel/utsname_sysctl.c
new file mode 100644 (file)
index 0000000..c8eac43
--- /dev/null
+++ b/kernel/kernel/utsname_sysctl.c
@@ -0,0 +1,138 @@
+/*
+ *  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/export.h>
+#include <linux/uts.h>
+#include <linux/utsname.h>
+#include <linux/sysctl.h>
+#include <linux/wait.h>
+
+#ifdef CONFIG_PROC_SYSCTL
+
+static void *get_uts(struct ctl_table *table, int write)
+{
+       char *which = table->data;
+       struct uts_namespace *uts_ns;
+
+       uts_ns = current->nsproxy->uts_ns;
+       which = (which - (char *)&init_uts_ns) + (char *)uts_ns;
+
+       if (!write)
+               down_read(&uts_sem);
+       else
+               down_write(&uts_sem);
+       return which;
+}
+
+static void put_uts(struct ctl_table *table, int write, void *which)
+{
+       if (!write)
+               up_read(&uts_sem);
+       else
+               up_write(&uts_sem);
+}
+
+/*
+ *     Special case of dostring for the UTS structure. This has locks
+ *     to observe. Should this be in kernel/sys.c ????
+ */
+static int proc_do_uts_string(struct ctl_table *table, int write,
+                 void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+       struct ctl_table uts_table;
+       int r;
+       memcpy(&uts_table, table, sizeof(uts_table));
+       uts_table.data = get_uts(table, write);
+       r = proc_dostring(&uts_table, write, buffer, lenp, ppos);
+       put_uts(table, write, uts_table.data);
+
+       if (write)
+               proc_sys_poll_notify(table->poll);
+
+       return r;
+}
+#else
+#define proc_do_uts_string NULL
+#endif
+
+static DEFINE_CTL_TABLE_POLL(hostname_poll);
+static DEFINE_CTL_TABLE_POLL(domainname_poll);
+
+static struct ctl_table uts_kern_table[] = {
+       {
+               .procname       = "ostype",
+               .data           = init_uts_ns.name.sysname,
+               .maxlen         = sizeof(init_uts_ns.name.sysname),
+               .mode           = 0444,
+               .proc_handler   = proc_do_uts_string,
+       },
+       {
+               .procname       = "osrelease",
+               .data           = init_uts_ns.name.release,
+               .maxlen         = sizeof(init_uts_ns.name.release),
+               .mode           = 0444,
+               .proc_handler   = proc_do_uts_string,
+       },
+       {
+               .procname       = "version",
+               .data           = init_uts_ns.name.version,
+               .maxlen         = sizeof(init_uts_ns.name.version),
+               .mode           = 0444,
+               .proc_handler   = proc_do_uts_string,
+       },
+       {
+               .procname       = "hostname",
+               .data           = init_uts_ns.name.nodename,
+               .maxlen         = sizeof(init_uts_ns.name.nodename),
+               .mode           = 0644,
+               .proc_handler   = proc_do_uts_string,
+               .poll           = &hostname_poll,
+       },
+       {
+               .procname       = "domainname",
+               .data           = init_uts_ns.name.domainname,
+               .maxlen         = sizeof(init_uts_ns.name.domainname),
+               .mode           = 0644,
+               .proc_handler   = proc_do_uts_string,
+               .poll           = &domainname_poll,
+       },
+       {}
+};
+
+static struct ctl_table uts_root_table[] = {
+       {
+               .procname       = "kernel",
+               .mode           = 0555,
+               .child          = uts_kern_table,
+       },
+       {}
+};
+
+#ifdef CONFIG_PROC_SYSCTL
+/*
+ * Notify userspace about a change in a certain entry of uts_kern_table,
+ * identified by the parameter proc.
+ */
+void uts_proc_notify(enum uts_proc proc)
+{
+       struct ctl_table *table = &uts_kern_table[proc];
+
+       proc_sys_poll_notify(table->poll);
+}
+#endif
+
+static int __init utsname_sysctl_init(void)
+{
+       register_sysctl_table(uts_root_table);
+       return 0;
+}
+
+device_initcall(utsname_sysctl_init);