Add new helper function to allow for splitting specified user string
into a sequence of integers. Internally it makes use of get_options() so
the returned sequence contains the integers extracted plus an additional
element that begins the sequence and specifies the integers count.
Suggested-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Signed-off-by: Cezary Rojewski <cezary.rojewski@xxxxxxxxx>
---
include/linux/string_helpers.h | 2 ++
lib/string_helpers.c | 45 ++++++++++++++++++++++++++++++++++
2 files changed, 47 insertions(+)
diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index 4d72258d42fd..dc2e726fd820 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -21,6 +21,8 @@ enum string_size_units {
void string_get_size(u64 size, u64 blk_size, enum string_size_units units,
char *buf, int len);
+int parse_int_array_user(const char __user *from, size_t count, int **array);
+
#define UNESCAPE_SPACE BIT(0)
#define UNESCAPE_OCTAL BIT(1)
#define UNESCAPE_HEX BIT(2)
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 5ed3beb066e6..d0c8f6ecf84c 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -131,6 +131,51 @@ void string_get_size(u64 size, u64 blk_size, const enum string_size_units units,
}
EXPORT_SYMBOL(string_get_size);
+/**
+ * parse_int_array_user - Split string into a sequence of integers
+ * @from: The user space buffer to read from
+ * @ppos: The current position in the buffer
+ * @count: The maximum number of bytes to read
+ * @tkns: Returned pointer to sequence of integers
+ *
+ * On success @tkns is allocated and initialized with a sequence of
+ * integers extracted from the @from plus an additional element that
+ * begins the sequence and specifies the integers count.
+ *
+ * Caller takes responsibility for freeing @tkns when it is no longer
+ * needed.
+ */
+int parse_int_array_user(const char __user *from, size_t count, int **array)
+{
+ int *ints, nints;
+ char *buf;
+ int ret = 0;
+
+ buf = memdup_user_nul(from, count);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ get_options(buf, 0, &nints);
+ if (!nints) {
+ ret = -ENOENT;
+ goto free_buf;
+ }
+
+ ints = kcalloc(nints + 1, sizeof(*ints), GFP_KERNEL);
+ if (!ints) {
+ ret = -ENOMEM;
+ goto free_buf;
+ }
+
+ get_options(buf, nints + 1, ints);
+ *array = ints;
+
+free_buf:
+ kfree(buf);
+ return ret;
+}
+EXPORT_SYMBOL(parse_int_array_user);
+
static bool unescape_space(char **src, char **dst)
{
char *p = *dst, *q = *src;
--
2.25.1
