[PATCH v2 08/12] sysinfo: Add support for iterating string list

Marek Behún
2021-11-03T23:24:53Z

From: Marek Behún <marek.behun@nic.cz>

Add function
sysinfo_get_str_list_max_len()
to determine length of the longest string in a string list, functions
sysinfo_str_list_first() and
sysinfo_str_list_next()
to support iteration over string list elements and macro
for_each_sysinfo_str_list()
to make the iteration simple to use.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
---
drivers/sysinfo/sysinfo-uclass.c | 79 +++++++++++++++++++++++++
include/sysinfo.h | 99 ++++++++++++++++++++++++++++++++
test/dm/sysinfo.c | 35 +++++++++++
3 files changed, 213 insertions(+)

diff --git a/drivers/sysinfo/sysinfo-uclass.c b/drivers/sysinfo/sysinfo-uclass.c
index d945f073c5..78035a95aa 100644
--- a/drivers/sysinfo/sysinfo-uclass.c
+++ b/drivers/sysinfo/sysinfo-uclass.c
@@ -8,6 +8,7 @@

#include <common.h>
#include <dm.h>
+#include <malloc.h>
#include <sysinfo.h>

struct sysinfo_priv {
@@ -104,6 +105,84 @@ int sysinfo_get_str_list(struct udevice *dev, int id, unsigned idx, size_t size,
return ops->get_str_list(dev, id, idx, size, val);
}

+int sysinfo_get_str_list_max_len(struct udevice *dev, int id)
+{
+ int maxlen = 0;
+ unsigned i;
+
+ /* first find out length of the longest string in the list */
+ for (i = 0; ; ++i) {
+ char dummy[1];
+ int len;
+
+ len = sysinfo_get_str_list(dev, id, i, 0, dummy);
+ if (len == -ERANGE)
+ break;
+ else if (len < 0)
+ return len;
+ else if (len > maxlen)
+ maxlen = len;
+ }
+
+ return maxlen;
+}
+
+struct sysinfo_str_list_iter {
+ struct udevice *dev;
+ int id;
+ size_t size;
+ unsigned idx;
+ char value[];
+};
+
+char *sysinfo_str_list_first(struct udevice *dev, int id, void *_iter)
+{
+ struct sysinfo_str_list_iter *iter, **iterp = _iter;
+ int maxlen, res;
+
+ maxlen = sysinfo_get_str_list_max_len(dev, id);
+ if (maxlen < 0)
+ return NULL;
+
+ iter = malloc(sizeof(struct sysinfo_str_list_iter) + maxlen + 1);
+ if (!iter) {
+ printf("No memory for sysinfo string list iterator\n");
+ return NULL;
+ }
+
+ iter->dev = dev;
+ iter->id = id;
+ iter->size = maxlen + 1;
+ iter->idx = 0;
+
+ res = sysinfo_get_str_list(dev, id, 0, iter->size, iter->value);
+ if (res < 0) {
+ *iterp = NULL;
+ free(iter);
+ return NULL;
+ }
+
+ *iterp = iter;
+
+ return iter->value;
+}
+
+char *sysinfo_str_list_next(void *_iter)
+{
+ struct sysinfo_str_list_iter **iterp = _iter, *iter = *iterp;
+ int res;
+
+ res = sysinfo_get_str_list(iter->dev, iter->id, ++iter->idx, iter->size,
+ iter->value);
+ if (res < 0) {
+ *iterp = NULL;
+ free(iter);
+ return NULL;
+ }
+
+ return iter->value;
+}
+
UCLASS_DRIVER(sysinfo) = {
.id = UCLASS_SYSINFO,
.name = "sysinfo",
diff --git a/include/sysinfo.h b/include/sysinfo.h
index 0d8a2d1676..d32bf3e808 100644
--- a/include/sysinfo.h
+++ b/include/sysinfo.h
@@ -218,6 +218,61 @@ int sysinfo_get_str(struct udevice *dev, int id, size_t size, char *val);
int sysinfo_get_str_list(struct udevice *dev, int id, unsigned idx, size_t size,
char *val);

+/**
+ * sysinfo_get_str_list_max_len() - Get length of longest string in a string
+ * list that describes hardware setup.
+ * @dev: The sysinfo instance to gather the data.
+ * @id: A unique identifier for the string list to read from.
+ *
+ * Return: Length (excluding the terminating NULL-byte) of the longest string in
+ * the string list, or -ve on error.
+ */
+int sysinfo_get_str_list_max_len(struct udevice *dev, int id);
+
+/**
+ * sysinfo_str_list_first() - Start iterating a string list.
+ * @dev: The sysinfo instance to gather the data.
+ * @id: A unique identifier for the string list to read from.
+ * @_iter: Pointer where iterator data will be stored.
+ *
+ * Pass a reference to a void * pointer as @_iter, i.e.
+ * void *iter;
+ * first = sysinfo_str_list_first(dev, id, &iter);
+ *
+ * The function will allocate space for the value. You need to iterate all
+ * elements with sysinfo_str_list_next() for the space to be freed, or free
+ * the pointer stored in @_iter, i.e.
+ * void *iter;
+ * first = sysinfo_str_list_first(dev, id, &iter);
+ * if (first)
+ * free(iter);
+ *
+ * Return: First string in the string list, or NULL on error.
+ */
+char *sysinfo_str_list_first(struct udevice *dev, int id, void *_iter);
+
+/**
+ * sysinfo_str_list_next() - Get next string in the string string list.
+ * @_iter: Pointer to iterator, filled in by sysinfo_str_list_first().
+ *
+ * Pass a reference to a void * pointer as @_iter, i.e.
+ * void *iter;
+ * first = sysinfo_str_list_first(dev, id, &iter);
+ * next = sysinfo_str_list_next(&iter);
+ *
+ * All elements must be iterated until the function returns NULL for the
+ * resources allocated for the iteration to be freed, or pointer stored in
+ * @_iter must be freed, i.e.:
+ * void *iter;
+ * first = sysinfo_str_list_first(dev, id, &iter);
+ * next = sysinfo_str_list_next(&iter);
+ * if (next)
+ * free(iter);
+ *
+ * Return: Next string in the string list, NULL on end of list or NULL on error.
+ */
+char *sysinfo_str_list_next(void *_iter);
+
/**
* sysinfo_get() - Return the sysinfo device for the sysinfo in question.
* @devp: Pointer to structure to receive the sysinfo device.
@@ -279,6 +334,22 @@ static inline int sysinfo_get_str_list(struct udevice *dev, int id,
return -ENOSYS;
}

+static inline int sysinfo_get_str_list_max_len(struct udevice *dev, int id)
+{
+ return -ENOSYS;
+}
+
+static inline char *sysinfo_str_list_first(struct udevice *dev, int id,
+ void *_iter)
+{
+ return NULL;
+}
+
+static inline char *sysinfo_str_list_next(void *_iter)
+{
+ return NULL;
+}
+
static inline int sysinfo_get(struct udevice **devp)
{
return -ENOSYS;
@@ -291,4 +362,32 @@ static inline int sysinfo_get_fit_loadable(struct udevice *dev, int index,
}

#endif
+
+/**
+ * for_each_sysinfo_str_list - Iterate a sysinfo string list
+ * @dev: The sysinfo instance to gather the data.
+ * @id: A unique identifier for the string list to read from.
+ * @val: String pointer for the value.
+ * @iter: Pointer where iteration data are stored.
+ *
+ * Important: all elements of the list must be iterated for the iterator
+ * resources to be freed automatically. If you need to break from the for cycle,
+ * you need to free the iterator.
+ *
+ * Example:
+ * char *value;
+ * void *iter;
+ * for_each_sysinfo_str_list(dev, MY_STR_LIST, value, iter) {
+ * printf("Value: %s\n", value);
+ * if (!strcmp(value, "needle")) {
+ * free(iter);
+ * break;
+ * }
+ * }
+ */
+#define for_each_sysinfo_str_list(dev, id, val, iter) \
+ for ((val) = sysinfo_str_list_first((dev), (id), &(iter)); \
+ (val); \
+ (val) = sysinfo_str_list_next(&(iter)))
+
#endif
diff --git a/test/dm/sysinfo.c b/test/dm/sysinfo.c
index a6b246f2df..e9b70d8e1a 100644
--- a/test/dm/sysinfo.c
+++ b/test/dm/sysinfo.c
@@ -75,3 +75,38 @@ static int dm_test_sysinfo(struct unit_test_state *uts)
}

DM_TEST(dm_test_sysinfo, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
+
+static int dm_test_sysinfo_str_list_iter(struct unit_test_state *uts)
+{
+ struct udevice *sysinfo;
+ char *value;
+ void *iter;
+ int idx;
+
+ ut_assertok(sysinfo_get(&sysinfo));
+ ut_assert(sysinfo);
+
+ sysinfo_detect(sysinfo);
+
+ idx = 0;
+ for_each_sysinfo_str_list(sysinfo, STR_VACATIONSPOT, value, iter) {
+ switch (idx) {
+ case 0:
+ ut_asserteq_str(value, "R'lyeh");
+ break;
+ case 2:
+ ut_asserteq_str(value, "Plateau of Leng");
+ break;
+ case 3:
+ ut_asserteq_str(value, "Carcosa");
+ break;
+ }
+ ++idx;
+ }
+
+ ut_assert(NULL == iter);
+
+ return 0;
+}
+
+DM_TEST(dm_test_sysinfo_str_list_iter, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
--
2.32.0