lib / string_helpers: introduce string_escape_mem()

This is almost the opposite function to string_unescape().  Nevertheless
it handles \0 and could be used for any byte buffer.

The documentation is supplied together with the function prototype.

The test cases covers most of the scenarios and would be expanded later
on.

[akpm@linux-foundation.org: avoid 1k stack consumption]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 236 insertions, 4 deletions

diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c
index ac44c9245dcf..ab0d30e1e18f 100644
--- a/lib/test-string_helpers.c
+++ b/lib/test-string_helpers.c
@@ -5,6 +5,7 @@
 
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/random.h>
 #include <linux/string.h>
@@ -62,10 +63,14 @@ static const struct test_string strings[] __initconst = {
 static void __init test_string_unescape(const char *name, unsigned int flags,
 					bool inplace)
 {
-	char in[256];
-	char out_test[256];
-	char out_real[256];
-	int i, p = 0, q_test = 0, q_real = sizeof(out_real);
+	int q_real = 256;
+	char *in = kmalloc(q_real, GFP_KERNEL);
+	char *out_test = kmalloc(q_real, GFP_KERNEL);
+	char *out_real = kmalloc(q_real, GFP_KERNEL);
+	int i, p = 0, q_test = 0;
+
+	if (!in || !out_test || !out_real)
+		goto out;
 
 	for (i = 0; i < ARRAY_SIZE(strings); i++) {
 		const char *s = strings[i].in;
@@ -100,6 +105,223 @@ static void __init test_string_unescape(const char *name, unsigned int flags,
 
 	test_string_check_buf(name, flags, in, p - 1, out_real, q_real,
 			      out_test, q_test);
+out:
+	kfree(out_real);
+	kfree(out_test);
+	kfree(in);
+}
+
+struct test_string_1 {
+	const char *out;
+	unsigned int flags;
+};
+
+#define	TEST_STRING_2_MAX_S1		32
+struct test_string_2 {
+	const char *in;
+	struct test_string_1 s1[TEST_STRING_2_MAX_S1];
+};
+
+#define	TEST_STRING_2_DICT_0		NULL
+static const struct test_string_2 escape0[] __initconst = {{
+	.in = "\f\\ \n\r\t\v",
+	.s1 = {{
+		.out = "\\f\\ \\n\\r\\t\\v",
+		.flags = ESCAPE_SPACE,
+	},{
+		.out = "\\f\\134\\040\\n\\r\\t\\v",
+		.flags = ESCAPE_SPACE | ESCAPE_OCTAL,
+	},{
+		.out = "\\f\\x5c\\x20\\n\\r\\t\\v",
+		.flags = ESCAPE_SPACE | ESCAPE_HEX,
+	},{
+		/* terminator */
+	}},
+},{
+	.in = "\\h\\\"\a\e\\",
+	.s1 = {{
+		.out = "\\\\h\\\\\"\\a\\e\\\\",
+		.flags = ESCAPE_SPECIAL,
+	},{
+		.out = "\\\\\\150\\\\\\042\\a\\e\\\\",
+		.flags = ESCAPE_SPECIAL | ESCAPE_OCTAL,
+	},{
+		.out = "\\\\\\x68\\\\\\x22\\a\\e\\\\",
+		.flags = ESCAPE_SPECIAL | ESCAPE_HEX,
+	},{
+		/* terminator */
+	}},
+},{
+	.in = "\eb \\C\007\"\x90\r]",
+	.s1 = {{
+		.out = "\eb \\C\007\"\x90\\r]",
+		.flags = ESCAPE_SPACE,
+	},{
+		.out = "\\eb \\\\C\\a\"\x90\r]",
+		.flags = ESCAPE_SPECIAL,
+	},{
+		.out = "\\eb \\\\C\\a\"\x90\\r]",
+		.flags = ESCAPE_SPACE | ESCAPE_SPECIAL,
+	},{
+		.out = "\\033\\142\\040\\134\\103\\007\\042\\220\\015\\135",
+		.flags = ESCAPE_OCTAL,
+	},{
+		.out = "\\033\\142\\040\\134\\103\\007\\042\\220\\r\\135",
+		.flags = ESCAPE_SPACE | ESCAPE_OCTAL,
+	},{
+		.out = "\\e\\142\\040\\\\\\103\\a\\042\\220\\015\\135",
+		.flags = ESCAPE_SPECIAL | ESCAPE_OCTAL,
+	},{
+		.out = "\\e\\142\\040\\\\\\103\\a\\042\\220\\r\\135",
+		.flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_OCTAL,
+	},{
+		.out = "\eb \\C\007\"\x90\r]",
+		.flags = ESCAPE_NP,
+	},{
+		.out = "\eb \\C\007\"\x90\\r]",
+		.flags = ESCAPE_SPACE | ESCAPE_NP,
+	},{
+		.out = "\\eb \\C\\a\"\x90\r]",
+		.flags = ESCAPE_SPECIAL | ESCAPE_NP,
+	},{
+		.out = "\\eb \\C\\a\"\x90\\r]",
+		.flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_NP,
+	},{
+		.out = "\\033b \\C\\007\"\\220\\015]",
+		.flags = ESCAPE_OCTAL | ESCAPE_NP,
+	},{
+		.out = "\\033b \\C\\007\"\\220\\r]",
+		.flags = ESCAPE_SPACE | ESCAPE_OCTAL | ESCAPE_NP,
+	},{
+		.out = "\\eb \\C\\a\"\\220\\r]",
+		.flags = ESCAPE_SPECIAL | ESCAPE_SPACE | ESCAPE_OCTAL |
+			 ESCAPE_NP,
+	},{
+		.out = "\\x1bb \\C\\x07\"\\x90\\x0d]",
+		.flags = ESCAPE_NP | ESCAPE_HEX,
+	},{
+		/* terminator */
+	}},
+},{
+	/* terminator */
+}};
+
+#define	TEST_STRING_2_DICT_1		"b\\ \t\r"
+static const struct test_string_2 escape1[] __initconst = {{
+	.in = "\f\\ \n\r\t\v",
+	.s1 = {{
+		.out = "\f\\134\\040\n\\015\\011\v",
+		.flags = ESCAPE_OCTAL,
+	},{
+		.out = "\f\\x5c\\x20\n\\x0d\\x09\v",
+		.flags = ESCAPE_HEX,
+	},{
+		/* terminator */
+	}},
+},{
+	.in = "\\h\\\"\a\e\\",
+	.s1 = {{
+		.out = "\\134h\\134\"\a\e\\134",
+		.flags = ESCAPE_OCTAL,
+	},{
+		/* terminator */
+	}},
+},{
+	.in = "\eb \\C\007\"\x90\r]",
+	.s1 = {{
+		.out = "\e\\142\\040\\134C\007\"\x90\\015]",
+		.flags = ESCAPE_OCTAL,
+	},{
+		/* terminator */
+	}},
+},{
+	/* terminator */
+}};
+
+static __init const char *test_string_find_match(const struct test_string_2 *s2,
+						 unsigned int flags)
+{
+	const struct test_string_1 *s1 = s2->s1;
+	unsigned int i;
+
+	if (!flags)
+		return s2->in;
+
+	/* Test cases are NULL-aware */
+	flags &= ~ESCAPE_NULL;
+
+	/* ESCAPE_OCTAL has a higher priority */
+	if (flags & ESCAPE_OCTAL)
+		flags &= ~ESCAPE_HEX;
+
+	for (i = 0; i < TEST_STRING_2_MAX_S1 && s1->out; i++, s1++)
+		if (s1->flags == flags)
+			return s1->out;
+	return NULL;
+}
+
+static __init void test_string_escape(const char *name,
+				      const struct test_string_2 *s2,
+				      unsigned int flags, const char *esc)
+{
+	int q_real = 512;
+	char *out_test = kmalloc(q_real, GFP_KERNEL);
+	char *out_real = kmalloc(q_real, GFP_KERNEL);
+	char *in = kmalloc(256, GFP_KERNEL);
+	char *buf = out_real;
+	int p = 0, q_test = 0;
+
+	if (!out_test || !out_real || !in)
+		goto out;
+
+	for (; s2->in; s2++) {
+		const char *out;
+		int len;
+
+		/* NULL injection */
+		if (flags & ESCAPE_NULL) {
+			in[p++] = '\0';
+			out_test[q_test++] = '\\';
+			out_test[q_test++] = '0';
+		}
+
+		/* Don't try strings that have no output */
+		out = test_string_find_match(s2, flags);
+		if (!out)
+			continue;
+
+		/* Copy string to in buffer */
+		len = strlen(s2->in);
+		memcpy(&in[p], s2->in, len);
+		p += len;
+
+		/* Copy expected result for given flags */
+		len = strlen(out);
+		memcpy(&out_test[q_test], out, len);
+		q_test += len;
+	}
+
+	q_real = string_escape_mem(in, p, &buf, q_real, flags, esc);
+
+	test_string_check_buf(name, flags, in, p, out_real, q_real, out_test,
+			      q_test);
+out:
+	kfree(in);
+	kfree(out_real);
+	kfree(out_test);
+}
+
+static __init void test_string_escape_nomem(void)
+{
+	char *in = "\eb \\C\007\"\x90\r]";
+	char out[64], *buf = out;
+	int rc = -ENOMEM, ret;
+
+	ret = string_escape_str_any_np(in, &buf, strlen(in), NULL);
+	if (ret == rc)
+		return;
+
+	pr_err("Test 'escape nomem' failed: got %d instead of %d\n", ret, rc);
 }
 
 static int __init test_string_helpers_init(void)
@@ -112,6 +334,16 @@ static int __init test_string_helpers_init(void)
 	test_string_unescape("unescape inplace",
 			     get_random_int() % (UNESCAPE_ANY + 1), true);
 
+	/* Without dictionary */
+	for (i = 0; i < (ESCAPE_ANY_NP | ESCAPE_HEX) + 1; i++)
+		test_string_escape("escape 0", escape0, i, TEST_STRING_2_DICT_0);
+
+	/* With dictionary */
+	for (i = 0; i < (ESCAPE_ANY_NP | ESCAPE_HEX) + 1; i++)
+		test_string_escape("escape 1", escape1, i, TEST_STRING_2_DICT_1);
+
+	test_string_escape_nomem();
+
 	return -EINVAL;
 }
 module_init(test_string_helpers_init);