Re: [PATCH v4 1/2] lib/string_helpers: Introduce parse_int_array_user()

On 9/2/2022 2:29 PM, Cezary Rojewski wrote:

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@gmail.com Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Signed-off-by: Cezary Rojewski cezary.rojewski@intel.com

---

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

There is no such parameter?

• • @count: The maximum number of bytes to read
• • @tkns: Returned pointer to sequence of integers

s/tkns/array/ ?

• • On success @tkns is allocated and initialized with a sequence of

ditto

• • 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

ditto

• • 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;