X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=kernel%2Futsname_sysctl.c;h=63da38c2d820920b270cc2f469b965e445fecc05;hb=9438ce9dbbf512fd717051284f568d5cb35e5cf1;hp=a2cd77e70d4d8359cf3e38b8fb61cc5388fe5cb4;hpb=cbee4751f612692c1de3b8e420ebcb0fb16c7c56;p=firefly-linux-kernel-4.4.55.git

diff --git a/kernel/utsname_sysctl.c b/kernel/utsname_sysctl.c
index a2cd77e70d4d..63da38c2d820 100644
--- a/kernel/utsname_sysctl.c
+++ b/kernel/utsname_sysctl.c
@@ -9,10 +9,11 @@
  *  License.
  */
 
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/uts.h>
 #include <linux/utsname.h>
 #include <linux/sysctl.h>
+#include <linux/wait.h>
 
 static void *get_uts(ctl_table *table, int write)
 {
@@ -51,12 +52,19 @@ static int proc_do_uts_string(ctl_table *table, int write,
 	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",
@@ -85,6 +93,7 @@ static struct ctl_table uts_kern_table[] = {
 		.maxlen		= sizeof(init_uts_ns.name.nodename),
 		.mode		= 0644,
 		.proc_handler	= proc_do_uts_string,
+		.poll		= &hostname_poll,
 	},
 	{
 		.procname	= "domainname",
@@ -92,6 +101,7 @@ static struct ctl_table uts_kern_table[] = {
 		.maxlen		= sizeof(init_uts_ns.name.domainname),
 		.mode		= 0644,
 		.proc_handler	= proc_do_uts_string,
+		.poll		= &domainname_poll,
 	},
 	{}
 };
@@ -105,6 +115,19 @@ static struct ctl_table uts_root_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);