diff mbox series

[v5,1/7] xen/dt: of_property_read_string return -ENODATA when !length

Message ID 20220429205732.2030094-1-sstabellini@kernel.org (mailing list archive)
State Superseded
Headers show
Series dom0less PV drivers | expand

Commit Message

Stefano Stabellini April 29, 2022, 8:57 p.m. UTC 
From: Stefano Stabellini <stefano.stabellini@xilinx.com>

When the length of the string is zero of_property_read_string should
return -ENODATA according to the description of the function.

However, of_property_read_string doesn't check prop->length. If
prop->length is zero, return -ENODATA.

Without this patch the following command in u-boot:

fdt set /chosen/node property-name

results in of_property_read_string returning -EILSEQ when attempting to
read property-name. With this patch, it returns -ENODATA as expected.

This commit is a backport of:
https://lore.kernel.org/xen-devel/20220416003028.1315268-1-sstabellini@kernel.org/

Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
---
Changes in v5:
- backport from Linux, I don't have the commit id yet so I used an LKML
  link instead for now
---
 xen/common/device_tree.c      | 2 +-
 xen/include/xen/device_tree.h | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

Comments

Luca Fancellu May 3, 2022, 10:15 a.m. UTC | #1 
> On 29 Apr 2022, at 21:57, Stefano Stabellini <sstabellini@kernel.org> wrote:
> 
> From: Stefano Stabellini <stefano.stabellini@xilinx.com>
> 
> When the length of the string is zero of_property_read_string should
> return -ENODATA according to the description of the function.
> 
> However, of_property_read_string doesn't check prop->length. If
> prop->length is zero, return -ENODATA.
> 
> Without this patch the following command in u-boot:
> 
> fdt set /chosen/node property-name
> 
> results in of_property_read_string returning -EILSEQ when attempting to
> read property-name. With this patch, it returns -ENODATA as expected.
> 
> This commit is a backport of:
> https://lore.kernel.org/xen-devel/20220416003028.1315268-1-sstabellini@kernel.org/
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>

Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>

> ---
> Changes in v5:
> - backport from Linux, I don't have the commit id yet so I used an LKML
>  link instead for now
Bertrand Marquis May 3, 2022, 10:34 a.m. UTC | #2 
Hi Stefano,

> On 29 Apr 2022, at 21:57, Stefano Stabellini <sstabellini@kernel.org> wrote:
> 
> From: Stefano Stabellini <stefano.stabellini@xilinx.com>
> 
> When the length of the string is zero of_property_read_string should
> return -ENODATA according to the description of the function.
> 
> However, of_property_read_string doesn't check prop->length. If
> prop->length is zero, return -ENODATA.
> 
> Without this patch the following command in u-boot:
> 
> fdt set /chosen/node property-name
> 
> results in of_property_read_string returning -EILSEQ when attempting to
> read property-name. With this patch, it returns -ENODATA as expected.
> 
> This commit is a backport of:
> https://lore.kernel.org/xen-devel/20220416003028.1315268-1-sstabellini@kernel.org/
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com>

Cheers
Bertrand
diff mbox series

Patch

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 4aae281e89..0e8798bd24 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -198,7 +198,7 @@  int dt_property_read_string(const struct dt_device_node *np,
 
     if ( !pp )
         return -EINVAL;
-    if ( !pp->value )
+    if ( !pp->length )
         return -ENODATA;
     if ( strnlen(pp->value, pp->length) >= pp->length )
         return -EILSEQ;
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index fd6cd00b43..430a1ef445 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -451,6 +451,9 @@  static inline bool_t dt_property_read_bool(const struct dt_device_node *np,
  * doest not have value, and -EILSEQ if the string is not
  * null-terminated with the length of the property data.
  *
+ * Note that the empty string "" has length of 1, thus -ENODATA cannot
+ * be interpreted as an empty string.
+ *
  * The out_string pointer is modified only if a valid string can be decoded.
  */
 int dt_property_read_string(const struct dt_device_node *np,