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 Signed-off-by: Cezary Rojewski cezary.rojewski@intel.com --- fs/libfs.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 1 + 2 files changed, 46 insertions(+)
diff --git a/fs/libfs.c b/fs/libfs.c index 31b0ddf01c31..078b23e26741 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -809,6 +809,51 @@ ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, } EXPORT_SYMBOL(simple_write_to_buffer);
+/** + * tokenize_user_input - 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 tokenize_user_input(const char __user *from, size_t count, int **tkns) +{ + 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); + *tkns = ints; + +free_buf: + kfree(buf); + return ret; +} +EXPORT_SYMBOL(tokenize_user_input); + /** * memory_read_from_buffer - copy data from the buffer * @to: the kernel space buffer to read to diff --git a/include/linux/fs.h b/include/linux/fs.h index 9eced4cc286e..ab04cc7f9efa 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3345,6 +3345,7 @@ extern ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, const void *from, size_t available); extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, const void __user *from, size_t count); +extern int tokenize_user_input(const char __user *from, size_t count, int **tkns);
extern int __generic_file_fsync(struct file *, loff_t, loff_t, int); extern int generic_file_fsync(struct file *, loff_t, loff_t, int);