lib: Add memcat_p(): paste 2 pointer arrays together (ce76d938) · Commits · 戴 / test

include/linux/string.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -131,6 +131,13 @@ static inline void memset_p(void p, void v, __kernel_size_t n)
		return memset64((uint64_t *)p, (uintptr_t)v, n);
		}

		extern void __memcat_p(void a, void **b);
		#define memcat_p(a, b) ({ \
		BUILD_BUG_ON_MSG(!__same_type((a), (b)), \
		"type mismatch in memcat_p()"); \
		(typeof(a) )__memcat_p((void )(a), (void )(b)); \
		})

		#ifndef __HAVE_ARCH_MEMCPY
		extern void * memcpy(void ,const void ,__kernel_size_t);
		#endif

lib/Kconfig.debug

+8 −0

Original line number	Diff line number	Diff line
		@@ -1965,6 +1965,14 @@ config TEST_DEBUG_VIRTUAL

		If unsure, say N.

		config TEST_MEMCAT_P
		tristate "Test memcat_p() helper function"
		help
		Test the memcat_p() helper for correctly merging two
		pointer arrays together.

		If unsure, say N.

		endif # RUNTIME_TESTING_MENU

		config MEMTEST

lib/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -71,6 +71,7 @@ obj-$(CONFIG_TEST_UUID) += test_uuid.o
		obj-$(CONFIG_TEST_PARMAN) += test_parman.o
		obj-$(CONFIG_TEST_KMOD) += test_kmod.o
		obj-$(CONFIG_TEST_DEBUG_VIRTUAL) += test_debug_virtual.o
		obj-$(CONFIG_TEST_MEMCAT_P) += test_memcat_p.o

		ifeq ($(CONFIG_DEBUG_KOBJECT),y)
		CFLAGS_kobject.o += -DDEBUG

lib/string.c

+31 −0

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@
		#include <linux/export.h>
		#include <linux/bug.h>
		#include <linux/errno.h>
		#include <linux/slab.h>

		#include <asm/byteorder.h>
		#include <asm/word-at-a-time.h>
		@@ -890,6 +891,36 @@ void memscan(void addr, int c, size_t size)
		EXPORT_SYMBOL(memscan);
		#endif

		/*
		* Merge two NULL-terminated pointer arrays into a newly allocated
		* array, which is also NULL-terminated. Nomenclature is inspired by
		* memset_p() and memcat() found elsewhere in the kernel source tree.
		*/
		void __memcat_p(void a, void **b)
		{
		void p = a, new;
		int nr;

		/* count the elements in both arrays */
		for (nr = 0, p = a; *p; nr++, p++)
		;
		for (p = b; *p; nr++, p++)
		;
		/* one for the NULL-terminator */
		nr++;

		new = kmalloc_array(nr, sizeof(void *), GFP_KERNEL);
		if (!new)
		return NULL;

		/* nr -> last index; p points to NULL in b[] */
		for (nr--; nr >= 0; nr--, p = p == b ? &a[nr] : p - 1)
		new[nr] = *p;

		return new;
		}
		EXPORT_SYMBOL_GPL(__memcat_p);

		#ifndef __HAVE_ARCH_STRSTR
		/**
		* strstr - Find the first substring in a %NUL terminated string

lib/test_memcat_p.c

0 → 100644

+115 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		/*
		* Test cases for memcat_p() in lib/string.c
		*/
		#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

		#include <linux/string.h>
		#include <linux/slab.h>
		#include <linux/module.h>

		struct test_struct {
		int num;
		unsigned int magic;
		};

		#define MAGIC 0xf00ff00f
		/* Size of each of the NULL-terminated input arrays */
		#define INPUT_MAX 128
		/* Expected number of non-NULL elements in the output array */
		#define EXPECT (INPUT_MAX * 2 - 2)

		static int __init test_memcat_p_init(void)
		{
		struct test_struct in0, in1, out, p;
		int err = -ENOMEM, i, r, total = 0;

		in0 = kcalloc(INPUT_MAX, sizeof(*in0), GFP_KERNEL);
		if (!in0)
		return err;

		in1 = kcalloc(INPUT_MAX, sizeof(*in1), GFP_KERNEL);
		if (!in1)
		goto err_free_in0;

		for (i = 0, r = 1; i < INPUT_MAX - 1; i++) {
		in0[i] = kmalloc(sizeof(**in0), GFP_KERNEL);
		if (!in0[i])
		goto err_free_elements;

		in1[i] = kmalloc(sizeof(**in1), GFP_KERNEL);
		if (!in1[i]) {
		kfree(in0[i]);
		goto err_free_elements;
		}

		/* lifted from test_sort.c */
		r = (r * 725861) % 6599;
		in0[i]->num = r;
		in1[i]->num = -r;
		in0[i]->magic = MAGIC;
		in1[i]->magic = MAGIC;
		}

		in0[i] = in1[i] = NULL;

		out = memcat_p(in0, in1);
		if (!out)
		goto err_free_all_elements;

		err = -EINVAL;
		for (i = 0, p = out; p && (i < INPUT_MAX 2 - 1); p++, i++) {
		total += (*p)->num;

		if ((*p)->magic != MAGIC) {
		pr_err("test failed: wrong magic at %d: %u\n", i,
		(*p)->magic);
		goto err_free_out;
		}
		}

		if (total) {
		pr_err("test failed: expected zero total, got %d\n", total);
		goto err_free_out;
		}

		if (i != EXPECT) {
		pr_err("test failed: expected output size %d, got %d\n",
		EXPECT, i);
		goto err_free_out;
		}

		for (i = 0; i < INPUT_MAX - 1; i++)
		if (out[i] != in0[i] \|\| out[i + INPUT_MAX - 1] != in1[i]) {
		pr_err("test failed: wrong element order at %d\n", i);
		goto err_free_out;
		}

		err = 0;
		pr_info("test passed\n");

		err_free_out:
		kfree(out);
		err_free_all_elements:
		i = INPUT_MAX;
		err_free_elements:
		for (i--; i >= 0; i--) {
		kfree(in1[i]);
		kfree(in0[i]);
		}

		kfree(in1);
		err_free_in0:
		kfree(in0);

		return err;
		}

		static void __exit test_memcat_p_exit(void)
		{
		}

		module_init(test_memcat_p_init);
		module_exit(test_memcat_p_exit);

		MODULE_LICENSE("GPL");

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