diff options
| -rw-r--r-- | include/linux/string.h | 7 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 8 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/string.c | 31 | ||||
| -rw-r--r-- | lib/test_memcat_p.c | 115 |
5 files changed, 162 insertions, 0 deletions
diff --git a/include/linux/string.h b/include/linux/string.h index 4a5a0eb7df51..27d0482e5e05 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -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 diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 4966c4fbe7f7..c0176510262e 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -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 diff --git a/lib/Makefile b/lib/Makefile index ca3f7ebb900d..c2588a2d7b1e 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -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 diff --git a/lib/string.c b/lib/string.c index 2c0900a5d51a..453f35994eb6 100644 --- a/lib/string.c +++ b/lib/string.c @@ -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 diff --git a/lib/test_memcat_p.c b/lib/test_memcat_p.c new file mode 100644 index 000000000000..2b163a749ecb --- /dev/null +++ b/lib/test_memcat_p.c @@ -0,0 +1,115 @@ +// 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"); |