mirror of https://gitee.com/openkylin/linux.git
test_printf: test printf family at runtime
This adds a simple module for testing the kernel's printf facilities. Previously, some %p extensions have caused a wrong return value in case the entire output didn't fit and/or been unusable in kasprintf(). This should help catch such issues. Also, it should help ensure that changes to the formatting algorithms don't break anything. I'm not sure if we have a struct dentry or struct file lying around at boot time or if we can fake one, but most %p extensions should be testable, as should the ordinary number and string formatting. The nature of vararg functions means we can't use a more conventional table-driven approach. For now, this is mostly a skeleton; contributions are very welcome. Some tests are/will be slightly annoying to write, since the expected output depends on stuff like CONFIG_*, sizeof(long), runtime values etc. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Martin Kletzander <mkletzan@redhat.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rasmus Villemoes
Linus Torvalds
parent
80c9eb46fa
commit
707cc7280f
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@ -1686,6 +1686,9 @@ config TEST_STRING_HELPERS
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config TEST_KSTRTOX
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tristate "Test kstrto*() family of functions at runtime"
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config TEST_PRINTF
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tristate "Test printf() family of functions at runtime"
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config TEST_RHASHTABLE
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tristate "Perform selftest on resizable hash table"
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default n
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@ -42,6 +42,7 @@ obj-$(CONFIG_TEST_RHASHTABLE) += test_rhashtable.o
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obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o
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obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
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obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
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obj-$(CONFIG_TEST_PRINTF) += test_printf.o
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ifeq ($(CONFIG_DEBUG_KOBJECT),y)
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CFLAGS_kobject.o += -DDEBUG
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@ -0,0 +1,362 @@
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/*
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* Test cases for printf facility.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/printk.h>
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#include <linux/random.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#define BUF_SIZE 256
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#define FILL_CHAR '$'
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#define PTR1 ((void*)0x01234567)
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#define PTR2 ((void*)(long)(int)0xfedcba98)
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#if BITS_PER_LONG == 64
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#define PTR1_ZEROES "000000000"
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#define PTR1_SPACES " "
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#define PTR1_STR "1234567"
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#define PTR2_STR "fffffffffedcba98"
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#define PTR_WIDTH 16
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#else
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#define PTR1_ZEROES "0"
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#define PTR1_SPACES " "
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#define PTR1_STR "1234567"
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#define PTR2_STR "fedcba98"
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#define PTR_WIDTH 8
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#endif
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#define PTR_WIDTH_STR stringify(PTR_WIDTH)
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static unsigned total_tests __initdata;
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static unsigned failed_tests __initdata;
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static char *test_buffer __initdata;
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static int __printf(4, 0) __init
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do_test(int bufsize, const char *expect, int elen,
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const char *fmt, va_list ap)
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{
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va_list aq;
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int ret, written;
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total_tests++;
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memset(test_buffer, FILL_CHAR, BUF_SIZE);
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va_copy(aq, ap);
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ret = vsnprintf(test_buffer, bufsize, fmt, aq);
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va_end(aq);
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if (ret != elen) {
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pr_warn("vsnprintf(buf, %d, \"%s\", ...) returned %d, expected %d\n",
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bufsize, fmt, ret, elen);
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return 1;
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}
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if (!bufsize) {
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if (memchr_inv(test_buffer, FILL_CHAR, BUF_SIZE)) {
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pr_warn("vsnprintf(buf, 0, \"%s\", ...) wrote to buffer\n",
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fmt);
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return 1;
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}
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return 0;
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}
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written = min(bufsize-1, elen);
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if (test_buffer[written]) {
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pr_warn("vsnprintf(buf, %d, \"%s\", ...) did not nul-terminate buffer\n",
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bufsize, fmt);
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return 1;
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}
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if (memcmp(test_buffer, expect, written)) {
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pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote '%s', expected '%.*s'\n",
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bufsize, fmt, test_buffer, written, expect);
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return 1;
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}
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return 0;
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}
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static void __printf(3, 4) __init
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__test(const char *expect, int elen, const char *fmt, ...)
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{
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va_list ap;
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int rand;
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char *p;
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BUG_ON(elen >= BUF_SIZE);
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va_start(ap, fmt);
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/*
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* Every fmt+args is subjected to four tests: Three where we
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* tell vsnprintf varying buffer sizes (plenty, not quite
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* enough and 0), and then we also test that kvasprintf would
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* be able to print it as expected.
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*/
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failed_tests += do_test(BUF_SIZE, expect, elen, fmt, ap);
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rand = 1 + prandom_u32_max(elen+1);
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/* Since elen < BUF_SIZE, we have 1 <= rand <= BUF_SIZE. */
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failed_tests += do_test(rand, expect, elen, fmt, ap);
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failed_tests += do_test(0, expect, elen, fmt, ap);
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p = kvasprintf(GFP_KERNEL, fmt, ap);
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if (p) {
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if (memcmp(p, expect, elen+1)) {
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pr_warn("kvasprintf(..., \"%s\", ...) returned '%s', expected '%s'\n",
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fmt, p, expect);
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failed_tests++;
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}
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kfree(p);
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}
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va_end(ap);
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}
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#define test(expect, fmt, ...) \
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__test(expect, strlen(expect), fmt, ##__VA_ARGS__)
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static void __init
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test_basic(void)
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{
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/* Work around annoying "warning: zero-length gnu_printf format string". */
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char nul = '\0';
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test("", &nul);
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test("100%", "100%%");
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test("xxx%yyy", "xxx%cyyy", '%');
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__test("xxx\0yyy", 7, "xxx%cyyy", '\0');
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}
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static void __init
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test_number(void)
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{
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test("0x1234abcd ", "%#-12x", 0x1234abcd);
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test(" 0x1234abcd", "%#12x", 0x1234abcd);
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test("0|001| 12|+123| 1234|-123|-1234", "%d|%03d|%3d|%+d|% d|%+d|% d", 0, 1, 12, 123, 1234, -123, -1234);
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}
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static void __init
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test_string(void)
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{
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test("", "%s%.0s", "", "123");
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test("ABCD|abc|123", "%s|%.3s|%.*s", "ABCD", "abcdef", 3, "123456");
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test("1 | 2|3 | 4|5 ", "%-3s|%3s|%-*s|%*s|%*s", "1", "2", 3, "3", 3, "4", -3, "5");
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/*
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* POSIX and C99 say that a missing precision should be
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* treated as a precision of 0. However, the kernel's printf
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* implementation treats this case as if the . wasn't
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* present. Let's add a test case documenting the current
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* behaviour; should anyone ever feel the need to follow the
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* standards more closely, this can be revisited.
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*/
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test("a||", "%.s|%.0s|%.*s", "a", "b", 0, "c");
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test("a | | ", "%-3.s|%-3.0s|%-3.*s", "a", "b", 0, "c");
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}
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static void __init
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plain(void)
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{
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test(PTR1_ZEROES PTR1_STR " " PTR2_STR, "%p %p", PTR1, PTR2);
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/*
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* The field width is overloaded for some %p extensions to
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* pass another piece of information. For plain pointers, the
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* behaviour is slightly odd: One cannot pass either the 0
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* flag nor a precision to %p without gcc complaining, and if
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* one explicitly gives a field width, the number is no longer
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* zero-padded.
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*/
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test("|" PTR1_STR PTR1_SPACES " | " PTR1_SPACES PTR1_STR "|",
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"|%-*p|%*p|", PTR_WIDTH+2, PTR1, PTR_WIDTH+2, PTR1);
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test("|" PTR2_STR " | " PTR2_STR "|",
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"|%-*p|%*p|", PTR_WIDTH+2, PTR2, PTR_WIDTH+2, PTR2);
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/*
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* Unrecognized %p extensions are treated as plain %p, but the
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* alphanumeric suffix is ignored (that is, does not occur in
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* the output.)
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*/
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test("|"PTR1_ZEROES PTR1_STR"|", "|%p0y|", PTR1);
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test("|"PTR2_STR"|", "|%p0y|", PTR2);
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}
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static void __init
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symbol_ptr(void)
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{
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}
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static void __init
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kernel_ptr(void)
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{
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}
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static void __init
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struct_resource(void)
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{
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}
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static void __init
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addr(void)
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{
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}
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static void __init
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escaped_str(void)
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{
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}
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static void __init
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hex_string(void)
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{
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const char buf[3] = {0xc0, 0xff, 0xee};
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test("c0 ff ee|c0:ff:ee|c0-ff-ee|c0ffee",
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"%3ph|%3phC|%3phD|%3phN", buf, buf, buf, buf);
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test("c0 ff ee|c0:ff:ee|c0-ff-ee|c0ffee",
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"%*ph|%*phC|%*phD|%*phN", 3, buf, 3, buf, 3, buf, 3, buf);
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}
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static void __init
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mac(void)
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{
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const u8 addr[6] = {0x2d, 0x48, 0xd6, 0xfc, 0x7a, 0x05};
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test("2d:48:d6:fc:7a:05", "%pM", addr);
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test("05:7a:fc:d6:48:2d", "%pMR", addr);
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test("2d-48-d6-fc-7a-05", "%pMF", addr);
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test("2d48d6fc7a05", "%pm", addr);
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test("057afcd6482d", "%pmR", addr);
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}
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static void __init
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ip4(void)
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{
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struct sockaddr_in sa;
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sa.sin_family = AF_INET;
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sa.sin_port = cpu_to_be16(12345);
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sa.sin_addr.s_addr = cpu_to_be32(0x7f000001);
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test("127.000.000.001|127.0.0.1", "%pi4|%pI4", &sa.sin_addr, &sa.sin_addr);
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test("127.000.000.001|127.0.0.1", "%piS|%pIS", &sa, &sa);
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sa.sin_addr.s_addr = cpu_to_be32(0x01020304);
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test("001.002.003.004:12345|1.2.3.4:12345", "%piSp|%pISp", &sa, &sa);
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}
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static void __init
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ip6(void)
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{
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}
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static void __init
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ip(void)
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{
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ip4();
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ip6();
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}
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static void __init
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uuid(void)
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{
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const char uuid[16] = {0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7,
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0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf};
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test("00010203-0405-0607-0809-0a0b0c0d0e0f", "%pUb", uuid);
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test("00010203-0405-0607-0809-0A0B0C0D0E0F", "%pUB", uuid);
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test("03020100-0504-0706-0809-0a0b0c0d0e0f", "%pUl", uuid);
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test("03020100-0504-0706-0809-0A0B0C0D0E0F", "%pUL", uuid);
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}
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static void __init
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dentry(void)
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{
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}
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static void __init
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struct_va_format(void)
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{
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}
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static void __init
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struct_clk(void)
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{
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}
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static void __init
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bitmap(void)
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{
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DECLARE_BITMAP(bits, 20);
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const int primes[] = {2,3,5,7,11,13,17,19};
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int i;
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bitmap_zero(bits, 20);
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test("00000|00000", "%20pb|%*pb", bits, 20, bits);
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test("|", "%20pbl|%*pbl", bits, 20, bits);
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for (i = 0; i < ARRAY_SIZE(primes); ++i)
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set_bit(primes[i], bits);
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test("a28ac|a28ac", "%20pb|%*pb", bits, 20, bits);
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test("2-3,5,7,11,13,17,19|2-3,5,7,11,13,17,19", "%20pbl|%*pbl", bits, 20, bits);
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bitmap_fill(bits, 20);
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test("fffff|fffff", "%20pb|%*pb", bits, 20, bits);
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test("0-19|0-19", "%20pbl|%*pbl", bits, 20, bits);
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}
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static void __init
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netdev_features(void)
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{
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}
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static void __init
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test_pointer(void)
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{
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plain();
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symbol_ptr();
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kernel_ptr();
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struct_resource();
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addr();
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escaped_str();
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hex_string();
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mac();
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ip();
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uuid();
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dentry();
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struct_va_format();
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struct_clk();
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bitmap();
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netdev_features();
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}
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static int __init
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test_printf_init(void)
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{
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test_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
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if (!test_buffer)
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return -ENOMEM;
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test_basic();
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test_number();
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test_string();
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test_pointer();
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kfree(test_buffer);
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if (failed_tests == 0)
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pr_info("all %u tests passed\n", total_tests);
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else
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pr_warn("failed %u out of %u tests\n", failed_tests, total_tests);
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return failed_tests ? -EINVAL : 0;
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}
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module_init(test_printf_init);
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MODULE_AUTHOR("Rasmus Villemoes <linux@rasmusvillemoes.dk>");
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MODULE_LICENSE("GPL");
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