ACPI: detect invalid argument written to /proc/acpi/alarm

/proc/acpi/alarm can't be set correctly, here is a sample:

[root@localhost /]# echo "2006 09" > /proc/acpi/alarm
[root@localhost /]# cat /proc/acpi/alarm
2007-12-09 09:09:09
[root@localhost /]# echo "2006 04" > /proc/acpi/alarm
[root@localhost /]# cat /proc/acpi/alarm
2007-12-04 04:04:04
[root@localhost /]#

Obviously, it is wrong, it should consider it as an invalid input.

after this patch:

[root@localhost /]# echo "2008 09" > /proc/acpi/alarm
-bash: echo: write error: Invalid argument
[root@localhost /]#

Signed-off-by: Yi Yang <yi.y.yang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/acpi/sleep/proc.c b/drivers/acpi/sleep/proc.c
index 1538355c266b..fce78fbf5f64 100644
--- a/drivers/acpi/sleep/proc.c
+++ b/drivers/acpi/sleep/proc.c
@@ -178,6 +178,9 @@ static int get_date_field(char **p, u32 * value)
          * Try to find delimeter, only to insert null.  The end of the
          * string won't have one, but is still valid.
          */
+        if (*p == NULL)
+                return result;
+
         next = strpbrk(*p, "- :");
         if (next)
                 *next++ = '\0';
@@ -190,6 +193,8 @@ static int get_date_field(char **p, u32 * value)
 
         if (next)
                 *p = next;
+        else
+                *p = NULL;
 
         return result;
 }