1 files changed, 23 insertions, 0 deletions

diff --git a/kernel/utsname_sysctl.c b/kernel/utsname_sysctl.c
index a2cd77e70d4d..3b0d48ebf81d 100644
--- a/kernel/utsname_sysctl.c
+++ b/kernel/utsname_sysctl.c
@@ -13,6 +13,7 @@
 #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);