diff mbox

[v2,4/7] device_tree: qemu_fdt_getprop converted to use the error API

Message ID 1452093205-30167-5-git-send-email-eric.auger@linaro.org
State Superseded
Headers show

Commit Message

Auger Eric Jan. 6, 2016, 3:13 p.m. UTC
Current qemu_fdt_getprop exits if the property is not found. It is
sometimes needed to read an optional property, in which case we do
not wish to exit but simply returns a null value.

This patch converts qemu_fdt_getprop to accept an Error **, and existing
users are converted to pass &error_fatal. This preserves the existing
behaviour. Then to use the API with your optional semantic a null
parameter can be conveyed.

Signed-off-by: Eric Auger <eric.auger@linaro.org>


---

v1 -> v2:
- add a doc comment in the header file

RFC -> v1:
- get rid of qemu_fdt_getprop_optional and implement Peter's suggestion
  that consists in using the error API

Signed-off-by: Eric Auger <eric.auger@linaro.org>

---
 device_tree.c                | 11 ++++++-----
 include/sysemu/device_tree.h | 15 ++++++++++++++-
 2 files changed, 20 insertions(+), 6 deletions(-)

-- 
1.9.1

Comments

Auger Eric Jan. 7, 2016, 8:50 a.m. UTC | #1
Hi Peter,
On 01/07/2016 01:20 AM, Peter Crosthwaite wrote:
> On Wed, Jan 6, 2016 at 7:13 AM, Eric Auger <eric.auger@linaro.org> wrote:

>> Current qemu_fdt_getprop exits if the property is not found. It is

>> sometimes needed to read an optional property, in which case we do

>> not wish to exit but simply returns a null value.

>>

>> This patch converts qemu_fdt_getprop to accept an Error **, and existing

>> users are converted to pass &error_fatal. This preserves the existing

>> behaviour. Then to use the API with your optional semantic a null

>> parameter can be conveyed.

>>

>> Signed-off-by: Eric Auger <eric.auger@linaro.org>

>>

>> ---

>>

>> v1 -> v2:

>> - add a doc comment in the header file

>>

>> RFC -> v1:

>> - get rid of qemu_fdt_getprop_optional and implement Peter's suggestion

>>   that consists in using the error API

>>

>> Signed-off-by: Eric Auger <eric.auger@linaro.org>

>> ---

>>  device_tree.c                | 11 ++++++-----

>>  include/sysemu/device_tree.h | 15 ++++++++++++++-

>>  2 files changed, 20 insertions(+), 6 deletions(-)

>>

>> diff --git a/device_tree.c b/device_tree.c

>> index 8441e01..6ecc9da 100644

>> --- a/device_tree.c

>> +++ b/device_tree.c

>> @@ -321,18 +321,18 @@ int qemu_fdt_setprop_string(void *fdt, const char *node_path,

>>  }

>>

>>  const void *qemu_fdt_getprop(void *fdt, const char *node_path,

>> -                             const char *property, int *lenp)

>> +                             const char *property, int *lenp, Error **errp)

>>  {

>>      int len;

>>      const void *r;

>> +

>>      if (!lenp) {

>>          lenp = &len;

>>      }

>>      r = fdt_getprop(fdt, findnode_nofail(fdt, node_path), property, lenp);

>>      if (!r) {

>> -        error_report("%s: Couldn't get %s/%s: %s", __func__,

>> -                     node_path, property, fdt_strerror(*lenp));

>> -        exit(1);

>> +        error_setg(errp, "%s: Couldn't get %s/%s: %s", __func__,

>> +                  node_path, property, fdt_strerror(*lenp));

>>      }

>>      return r;

>>  }

>> @@ -341,7 +341,8 @@ uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,

>>                                 const char *property)

>>  {

>>      int len;

>> -    const uint32_t *p = qemu_fdt_getprop(fdt, node_path, property, &len);

>> +    const uint32_t *p = qemu_fdt_getprop(fdt, node_path, property, &len,

>> +                                         &error_fatal);

> 

> The _cell variant is now inconsistent with the regular _getprop. Can

> we convert them both together and fix the clients to error_fatal?

> (there are only 4 of them).


Yes sure

Best Regards

Eric
> 

> This would become the standard error_propagate pattern.

> 

>>      if (len != 4) {

>>          error_report("%s: %s/%s not 4 bytes long (not a cell?)",

>>                       __func__, node_path, property);

> 

> And this would also convert to error_setg.

> 

> Regards,

> Peter

> 

>> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h

>> index 269cb1c..4d7cbb9 100644

>> --- a/include/sysemu/device_tree.h

>> +++ b/include/sysemu/device_tree.h

>> @@ -45,8 +45,21 @@ int qemu_fdt_setprop_string(void *fdt, const char *node_path,

>>  int qemu_fdt_setprop_phandle(void *fdt, const char *node_path,

>>                               const char *property,

>>                               const char *target_node_path);

>> +/**

>> + * qemu_fdt_getprop: retrieve the value of a given property

>> + * @fdt: pointer to the device tree blob

>> + * @node_path: node path

>> + * @property: name of the property to find

>> + * @lenp: fdt error if any or length of the property on success

>> + * @errp: handle to an error object

>> + *

>> + * returns a pointer to the property on success and NULL on failure

>> + * in case errp is set to &error_fatal, the function auto-asserts

>> + * on error (legacy behavior)

>> + */

>>  const void *qemu_fdt_getprop(void *fdt, const char *node_path,

>> -                             const char *property, int *lenp);

>> +                             const char *property, int *lenp,

>> +                             Error **errp);

>>  uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,

>>                                 const char *property);

>>  uint32_t qemu_fdt_get_phandle(void *fdt, const char *path);

>> --

>> 1.9.1

>>
diff mbox

Patch

diff --git a/device_tree.c b/device_tree.c
index 8441e01..6ecc9da 100644
--- a/device_tree.c
+++ b/device_tree.c
@@ -321,18 +321,18 @@  int qemu_fdt_setprop_string(void *fdt, const char *node_path,
 }
 
 const void *qemu_fdt_getprop(void *fdt, const char *node_path,
-                             const char *property, int *lenp)
+                             const char *property, int *lenp, Error **errp)
 {
     int len;
     const void *r;
+
     if (!lenp) {
         lenp = &len;
     }
     r = fdt_getprop(fdt, findnode_nofail(fdt, node_path), property, lenp);
     if (!r) {
-        error_report("%s: Couldn't get %s/%s: %s", __func__,
-                     node_path, property, fdt_strerror(*lenp));
-        exit(1);
+        error_setg(errp, "%s: Couldn't get %s/%s: %s", __func__,
+                  node_path, property, fdt_strerror(*lenp));
     }
     return r;
 }
@@ -341,7 +341,8 @@  uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,
                                const char *property)
 {
     int len;
-    const uint32_t *p = qemu_fdt_getprop(fdt, node_path, property, &len);
+    const uint32_t *p = qemu_fdt_getprop(fdt, node_path, property, &len,
+                                         &error_fatal);
     if (len != 4) {
         error_report("%s: %s/%s not 4 bytes long (not a cell?)",
                      __func__, node_path, property);
diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
index 269cb1c..4d7cbb9 100644
--- a/include/sysemu/device_tree.h
+++ b/include/sysemu/device_tree.h
@@ -45,8 +45,21 @@  int qemu_fdt_setprop_string(void *fdt, const char *node_path,
 int qemu_fdt_setprop_phandle(void *fdt, const char *node_path,
                              const char *property,
                              const char *target_node_path);
+/**
+ * qemu_fdt_getprop: retrieve the value of a given property
+ * @fdt: pointer to the device tree blob
+ * @node_path: node path
+ * @property: name of the property to find
+ * @lenp: fdt error if any or length of the property on success
+ * @errp: handle to an error object
+ *
+ * returns a pointer to the property on success and NULL on failure
+ * in case errp is set to &error_fatal, the function auto-asserts
+ * on error (legacy behavior)
+ */
 const void *qemu_fdt_getprop(void *fdt, const char *node_path,
-                             const char *property, int *lenp);
+                             const char *property, int *lenp,
+                             Error **errp);
 uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path,
                                const char *property);
 uint32_t qemu_fdt_get_phandle(void *fdt, const char *path);