On Wed, Jan 6, 2016 at 7:13 AM, Eric Auger <eric.au...@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.au...@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.au...@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).
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
>
