[PATCH v2 4/4] lib/test_printf.c: add test cases for '%pD'

From: Jia He
Date: Wed Jun 23 2021 - 01:51:04 EST


After the behaviour of specifier '%pD' is changed to print the full path
of struct file, the related test cases are also updated.

Given the full path string of '%pD' is prepended from the end of the scratch
buffer, the check of "wrote beyond the nul-terminator" should be skipped
for '%pD'.

Parameterize the new using_scratch_space in __test(), do_test() and wrapper
macros to skip the test case mentioned above,

Signed-off-by: Jia He <justin.he@xxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
lib/test_printf.c | 49 +++++++++++++++++++++++++++++++++++++----------
1 file changed, 39 insertions(+), 10 deletions(-)

diff --git a/lib/test_printf.c b/lib/test_printf.c
index d1d2f898ebae..f48da88bc77b 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -16,6 +16,7 @@

#include <linux/bitmap.h>
#include <linux/dcache.h>
+#include <linux/fs.h>
#include <linux/socket.h>
#include <linux/in.h>

@@ -37,8 +38,8 @@ static char *alloced_buffer __initdata;

extern bool no_hash_pointers;

-static int __printf(4, 0) __init
-do_test(int bufsize, const char *expect, int elen,
+static int __printf(5, 0) __init
+do_test(int bufsize, const char *expect, int elen, bool using_scratch_space,
const char *fmt, va_list ap)
{
va_list aq;
@@ -78,7 +79,7 @@ do_test(int bufsize, const char *expect, int elen,
return 1;
}

- if (memchr_inv(test_buffer + written + 1, FILL_CHAR, bufsize - (written + 1))) {
+ if (!using_scratch_space && memchr_inv(test_buffer + written + 1, FILL_CHAR, bufsize - (written + 1))) {
pr_warn("vsnprintf(buf, %d, \"%s\", ...) wrote beyond the nul-terminator\n",
bufsize, fmt);
return 1;
@@ -97,8 +98,9 @@ do_test(int bufsize, const char *expect, int elen,
return 0;
}

-static void __printf(3, 4) __init
-__test(const char *expect, int elen, const char *fmt, ...)
+static void __printf(4, 5) __init
+__test(const char *expect, int elen, bool using_scratch_space,
+ const char *fmt, ...)
{
va_list ap;
int rand;
@@ -119,11 +121,11 @@ __test(const char *expect, int elen, const char *fmt, ...)
* enough and 0), and then we also test that kvasprintf would
* be able to print it as expected.
*/
- failed_tests += do_test(BUF_SIZE, expect, elen, fmt, ap);
+ failed_tests += do_test(BUF_SIZE, expect, elen, using_scratch_space, fmt, ap);
rand = 1 + prandom_u32_max(elen+1);
/* Since elen < BUF_SIZE, we have 1 <= rand <= BUF_SIZE. */
- failed_tests += do_test(rand, expect, elen, fmt, ap);
- failed_tests += do_test(0, expect, elen, fmt, ap);
+ failed_tests += do_test(rand, expect, elen, using_scratch_space, fmt, ap);
+ failed_tests += do_test(0, expect, elen, using_scratch_space, fmt, ap);

p = kvasprintf(GFP_KERNEL, fmt, ap);
if (p) {
@@ -138,8 +140,15 @@ __test(const char *expect, int elen, const char *fmt, ...)
va_end(ap);
}

+/*
+ * More relaxed test for non-standard formats that are using the provided buffer
+ * as a scratch space and write beyond the trailing '\0'.
+ */
+#define test_using_scratch_space(expect, fmt, ...) \
+ __test(expect, strlen(expect), true, fmt, ##__VA_ARGS__)
+
#define test(expect, fmt, ...) \
- __test(expect, strlen(expect), fmt, ##__VA_ARGS__)
+ __test(expect, strlen(expect), false, fmt, ##__VA_ARGS__)

static void __init
test_basic(void)
@@ -150,7 +159,7 @@ test_basic(void)
test("", &nul);
test("100%", "100%%");
test("xxx%yyy", "xxx%cyyy", '%');
- __test("xxx\0yyy", 7, "xxx%cyyy", '\0');
+ __test("xxx\0yyy", 7, false, "xxx%cyyy", '\0');
}

static void __init
@@ -501,6 +510,25 @@ dentry(void)
test(" bravo/alfa| bravo/alfa", "%12pd2|%*pd2", &test_dentry[2], 12, &test_dentry[2]);
}

+static struct vfsmount test_vfsmnt __initdata = {};
+
+static struct file test_file __initdata = {
+ .f_path = { .dentry = &test_dentry[2],
+ .mnt = &test_vfsmnt,
+ },
+};
+
+static void __init
+f_d_path(void)
+{
+ test("(null)", "%pD", NULL);
+ test("(efault)", "%pD", PTR_INVALID);
+
+ test_using_scratch_space("/bravo/alfa |/bravo/alfa ", "%-14pD|%*pD", &test_file, -14, &test_file);
+ test_using_scratch_space(" /bravo/alfa| /bravo/alfa", "%14pD|%*pD", &test_file, 14, &test_file);
+ test_using_scratch_space(" /bravo/alfa|/bravo/alfa ", "%14pD|%-14pD", &test_file, &test_file);
+}
+
static void __init
struct_va_format(void)
{
@@ -784,6 +812,7 @@ test_pointer(void)
ip();
uuid();
dentry();
+ f_d_path();
struct_va_format();
time_and_date();
struct_clk();
--
2.17.1