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ACPI: avoid empty file name in sysfs

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Since commit bc45b1d39a acpi tables are
allowed to have an empty signature and /sys/firmware/acpi/tables uses the
signature as filename.  Applications using naive recursion through /sys
loop forever.  A possible solution would be: (replacing the zero length
filename with the string "NULL")

http://bugzilla.kernel.org/show_bug.cgi?id=11539

Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Peter Gruber 2008-10-27 23:59:36 -04:00 committed by Len Brown
parent 49fdf6785f
commit 4feba70a2c
1 changed files with 17 additions and 8 deletions
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25
drivers/acpi/system.c
View file

@ -78,9 +78,15 @@ static ssize_t acpi_table_show(struct kobject *kobj,
container_of(bin_attr, struct acpi_table_attr, attr);
struct acpi_table_header *table_header = NULL;
acpi_status status;
char name[ACPI_NAME_SIZE];
if (strncmp(table_attr->name, "NULL", 4))
memcpy(name, table_attr->name, ACPI_NAME_SIZE);
else
memcpy(name, "\0\0\0\0", 4);
status =
acpi_get_table(table_attr->name, table_attr->instance,
acpi_get_table(name, table_attr->instance,
&table_header);
if (ACPI_FAILURE(status))
return -ENODEV;
@ -95,21 +101,24 @@ static void acpi_table_attr_init(struct acpi_table_attr *table_attr,
struct acpi_table_header *header = NULL;
struct acpi_table_attr *attr = NULL;
memcpy(table_attr->name, table_header->signature, ACPI_NAME_SIZE);
if (table_header->signature[0] != '\0')
memcpy(table_attr->name, table_header->signature,
ACPI_NAME_SIZE);
else
memcpy(table_attr->name, "NULL", 4);
list_for_each_entry(attr, &acpi_table_attr_list, node) {
if (!memcmp(table_header->signature, attr->name,
ACPI_NAME_SIZE))
if (!memcmp(table_attr->name, attr->name, ACPI_NAME_SIZE))
if (table_attr->instance < attr->instance)
table_attr->instance = attr->instance;
}
table_attr->instance++;
if (table_attr->instance > 1 || (table_attr->instance == 1 &&
!acpi_get_table(table_header->
signature, 2,
&header)))
sprintf(table_attr->name + 4, "%d", table_attr->instance);
!acpi_get_table
(table_header->signature, 2, &header)))
sprintf(table_attr->name + ACPI_NAME_SIZE, "%d",
table_attr->instance);
table_attr->attr.size = 0;
table_attr->attr.read = acpi_table_show;