Thread (43 messages) read the whole thread 43 messages, 6 authors, 2021-11-18

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

From: Joe Perches <joe@perches.com>
Date: 2021-11-06 07:35:03
Also in: linux-gpio, linux-rockchip, lkml

On Fri, 2021-11-05 at 14:42 +0200, Andy Shevchenko wrote:
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).
I think this is overkill and unnecessary bloat for the number of
actual or possible in-tree uses.  The devm_ variant too.

And it'd be useful to have an 0/n patch cover letter describing
why the patchset is useful so I could reply to that instead of the
1/n.
quoted hunk ↗ jump to hunk
diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
[]
quoted hunk ↗ jump to hunk
@@ -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
[]
quoted hunk ↗ jump to hunk
@@ -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


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