[PATCH v1 01/19] lib/string_helpers: Introduce kasprintf_strarray()

Andy Shevchenko
2021-11-05T12:43:14Z

We have a few users already that basically want to have array of
sequential strings to be allocated and filled.

Provide a helper for them (basically adjusted version from gpio-mockup.c).

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
include/linux/string_helpers.h | 1 +
lib/string_helpers.c | 33 +++++++++++++++++++++++++++++++++
2 files changed, 34 insertions(+)

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index 4ba39e1403b2..f67a94013c87 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -100,6 +100,7 @@ char *kstrdup_quotable(const char *src, gfp_t gfp);
char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp);
char *kstrdup_quotable_file(struct file *file, gfp_t gfp);

+char **kasprintf_strarray(gfp_t gfp, const char *prefix, size_t n);
void kfree_strarray(char **array, size_t n);

#endif
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index d5d008f5b1d9..9758997c465e 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -674,6 +674,39 @@ char *kstrdup_quotable_file(struct file *file, gfp_t gfp)
}
EXPORT_SYMBOL_GPL(kstrdup_quotable_file);

+/**
+ * kasprintf_strarray - allocate and fill array of sequential strings
+ * @gfp: flags for the slab allocator
+ * @prefix: prefix to be used
+ * @n: amount of lines to be allocated and filled
+ *
+ * Allocates and fills @n strings using pattern "%s-%zu", where prefix
+ * is provided by caller. The caller is responsible to free them with
+ * kfree_strarray() after use.
+ *
+ * Returns array of strings or NULL when memory can't be allocated.
+ */
+char **kasprintf_strarray(gfp_t gfp, const char *prefix, size_t n)
+{
+ char **names;
+ size_t i;
+
+ names = kcalloc(n + 1, sizeof(char *), gfp);
+ if (!names)
+ return NULL;
+
+ for (i = 0; i < n; i++) {
+ names[i] = kasprintf(gfp, "%s-%zu", prefix, i);
+ if (!names[i]) {
+ kfree_strarray(names, i);
+ return NULL;
+ }
+ }
+
+ return names;
+}
+EXPORT_SYMBOL_GPL(kasprintf_strarray);
+
/**
* kfree_strarray - free a number of dynamically allocated strings contained
* in an array and the array itself
--
2.33.0