add osmo_escape_cstr and osmo_quote_cstr

Provide string escaping that
- returns the required buffer size, so it can be used with OSMO_STRBUF_APPEND().
- uses C compatible string constant escaping sequences.

This is intended as a replacement for all previous osmo_escape_str* and
osmo_quote_str* API. It pains me that I didn't get them right the first nor the
second time:
- The buffer functions do not return the chars needed, which is required for
  allocating sufficient memory in the *_c versions of the functions.
- Because of that, these functions are accurately usable for
  OSMO_STRBUF_APPEND(), producing truncated strings, for example when dumping a
  GSUP message.
- They do not use the C equivalent string constant escaping: for some reason I
  thought "\15" would be valid, but it should be "\x0f".
If I could, I would completely drop those mislead implementations ... but
backwards compat prohibits that.

A previous patch already provided internal static functions that accurately
return the required buffer size. Enhance these to also support C compatible
string escaping, and use them as implementation of the new functions:

osmo_escape_cstr_buf()
osmo_escape_cstr_c()
osmo_quote_cstr_buf()
osmo_quote_cstr_c()

In the tests for these, also test C string equivalence.

Naming: from API versions, it would be kind of logical to call them
osmo_escape_str_buf3() and osmo_escape_str_c2(). Since these anyway return a
different escaping, it makes sense to me to have distinct names instead.

Quasi missing are variants of the non-C-compatible weird legacy escaping that
return the required buffer size, but I refrain from adding those, because we
have enough API cruft as it is. Just always use these new cstr variants.

Change-Id: I3dfb892036e01000033dd8e7e4a6a0c32a3caa9b

4 files changed, 301 insertions, 21 deletions

diff --git a/include/osmocom/core/utils.h b/include/osmocom/core/utils.h
index 1abbe989..01c4de6e 100644
--- a/include/osmocom/core/utils.h
+++ b/include/osmocom/core/utils.h
@@ -148,6 +148,11 @@ bool osmo_identifier_valid(const char *str);
 bool osmo_separated_identifiers_valid(const char *str, const char *sep_chars);
 void osmo_identifier_sanitize_buf(char *str, const char *sep_chars, char replace_with);
 
+size_t osmo_escape_cstr_buf(char *buf, size_t bufsize, const char *str, int in_len);
+char *osmo_escape_cstr_c(void *ctx, const char *str, int in_len);
+size_t osmo_quote_cstr_buf(char *buf, size_t bufsize, const char *str, int in_len);
+char *osmo_quote_cstr_c(void *ctx, const char *str, int in_len);
+
 const char *osmo_escape_str(const char *str, int len);
 char *osmo_escape_str_buf2(char *buf, size_t bufsize, const char *str, int in_len);
 const char *osmo_escape_str_buf(const char *str, int in_len, char *buf, size_t bufsize);
diff --git a/src/utils.c b/src/utils.c
index c3e3efbf..038288c5 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -693,14 +693,18 @@ int osmo_print_n(char *buf, size_t bufsize, const char *str, size_t n)
 
 /*! Return the string with all non-printable characters escaped.
  * This internal function is the implementation for all osmo_escape_str* and osmo_quote_str* API versions.
- * It provides a return value of characters-needed, to allow producing un-truncated strings in all cases.
+ * It provides both the legacy (non C compatible) escaping, as well as C compatible string constant syntax,
+ * and it provides a return value of characters-needed, to allow producing un-truncated strings in all cases.
  * \param[out] buf  string buffer to write escaped characters to.
  * \param[in] bufsize  sizeof(buf).
  * \param[in] str  A string that may contain any characters.
  * \param[in] in_len  Pass -1 to print until nul char, or >= 0 to force a length (also past nul chars).
+ * \param[in] legacy_format  If false, return C compatible string constants ("\x0f"), if true the legacy
+ *                           escaping format ("\15"). The legacy format also escapes as "\a\b\f\v", while
+ *                           the non-legacy format also escapes those as "\xNN" sequences.
  * \return Number of characters that would be written if bufsize were large enough excluding '\0' (like snprintf()).
  */
-static size_t _osmo_escape_str_buf(char *buf, size_t bufsize, const char *str, int in_len)
+static size_t _osmo_escape_str_buf(char *buf, size_t bufsize, const char *str, int in_len, bool legacy_format)
 {
 	struct osmo_strbuf sb = { .buf = buf, .len = bufsize };
 	int in_pos = 0;
@@ -739,19 +743,28 @@ static size_t _osmo_escape_str_buf(char *buf, size_t bufsize, const char *str, i
 		BACKSLASH_CASE('\r', 'r');
 		BACKSLASH_CASE('\t', 't');
 		BACKSLASH_CASE('\0', '0');
-		BACKSLASH_CASE('\a', 'a');
-		BACKSLASH_CASE('\b', 'b');
-		BACKSLASH_CASE('\v', 'v');
-		BACKSLASH_CASE('\f', 'f');
 		BACKSLASH_CASE('\\', '\\');
 		BACKSLASH_CASE('"', '"');
-#undef BACKSLASH_CASE
 
 		default:
-			OSMO_STRBUF_PRINTF(sb, "\\%u", (unsigned char)str[in_pos]);
+			if (legacy_format) {
+				switch (str[next_unprintable]) {
+				BACKSLASH_CASE('\a', 'a');
+				BACKSLASH_CASE('\b', 'b');
+				BACKSLASH_CASE('\v', 'v');
+				BACKSLASH_CASE('\f', 'f');
+				default:
+					OSMO_STRBUF_PRINTF(sb, "\\%u", (unsigned char)str[in_pos]);
+					break;
+				}
+				break;
+			}
+
+			OSMO_STRBUF_PRINTF(sb, "\\x%02x", (unsigned char)str[in_pos]);
 			break;
 		}
 		in_pos ++;
+#undef BACKSLASH_CASE
 	}
 
 done:
@@ -767,7 +780,7 @@ done:
  */
 char *osmo_escape_str_buf2(char *buf, size_t bufsize, const char *str, int in_len)
 {
-	_osmo_escape_str_buf(buf, bufsize, str, in_len);
+	_osmo_escape_str_buf(buf, bufsize, str, in_len, true);
 	return buf;
 }
 
@@ -791,26 +804,30 @@ char *osmo_escape_str_c(const void *ctx, const char *str, int in_len)
 {
 	/* The string will be at least as long as in_len, but some characters might need escaping.
 	 * These extra bytes should catch most usual escaping situations, avoiding a second run in OSMO_NAME_C_IMPL. */
-	OSMO_NAME_C_IMPL(ctx, in_len + 16, "ERROR", _osmo_escape_str_buf, str, in_len);
+	OSMO_NAME_C_IMPL(ctx, in_len + 16, "ERROR", _osmo_escape_str_buf, str, in_len, true);
 }
 
 /*! Return a quoted and escaped representation of the string.
  * This internal function is the implementation for all osmo_quote_str* API versions.
- * It provides a return value of characters-needed, to allow producing un-truncated strings in all cases.
+ * It provides both the legacy (non C compatible) escaping, as well as C compatible string constant syntax,
+ * and it provides a return value of characters-needed, to allow producing un-truncated strings in all cases.
  * \param[out] buf  string buffer to write escaped characters to.
  * \param[in] bufsize  sizeof(buf).
  * \param[in] str  A string that may contain any characters.
  * \param[in] in_len  Pass -1 to print until nul char, or >= 0 to force a length (also past nul chars).
+ * \param[in] legacy_format  If false, return C compatible string constants ("\x0f"), if true the legacy
+ *                           escaping format ("\15"). The legacy format also escapes as "\a\b\f\v", while
+ *                           the non-legacy format also escapes those as "\xNN" sequences.
  * \return Number of characters that would be written if bufsize were large enough excluding '\0' (like snprintf()).
  */
-static size_t _osmo_quote_str_buf(char *buf, size_t bufsize, const char *str, int in_len)
+static size_t _osmo_quote_str_buf(char *buf, size_t bufsize, const char *str, int in_len, bool legacy_format)
 {
 	struct osmo_strbuf sb = { .buf = buf, .len = bufsize };
 	if (!str)
 		OSMO_STRBUF_PRINTF(sb, "NULL");
 	else {
 		OSMO_STRBUF_PRINTF(sb, "\"");
-		OSMO_STRBUF_APPEND(sb, _osmo_escape_str_buf, str, in_len);
+		OSMO_STRBUF_APPEND(sb, _osmo_escape_str_buf, str, in_len, legacy_format);
 		OSMO_STRBUF_PRINTF(sb, "\"");
 	}
 	return sb.chars_needed;
@@ -827,7 +844,7 @@ static size_t _osmo_quote_str_buf(char *buf, size_t bufsize, const char *str, in
  */
 char *osmo_quote_str_buf2(char *buf, size_t bufsize, const char *str, int in_len)
 {
-	_osmo_quote_str_buf(buf, bufsize, str, in_len);
+	_osmo_quote_str_buf(buf, bufsize, str, in_len, true);
 	return buf;
 }
 
@@ -845,7 +862,7 @@ const char *osmo_quote_str_buf(const char *str, int in_len, char *buf, size_t bu
 		return "NULL";
 	if (!buf || !bufsize)
 		return "(error)";
-	_osmo_quote_str_buf(buf, bufsize, str, in_len);
+	_osmo_quote_str_buf(buf, bufsize, str, in_len, true);
 	return buf;
 }
 
@@ -857,7 +874,7 @@ const char *osmo_quote_str_buf(const char *str, int in_len, char *buf, size_t bu
  */
 const char *osmo_quote_str(const char *str, int in_len)
 {
-	_osmo_quote_str_buf(namebuf, sizeof(namebuf), str, in_len);
+	_osmo_quote_str_buf(namebuf, sizeof(namebuf), str, in_len, true);
 	return namebuf;
 }
 
@@ -870,7 +887,65 @@ char *osmo_quote_str_c(const void *ctx, const char *str, int in_len)
 {
 	/* The string will be at least as long as in_len, but some characters might need escaping.
 	 * These extra bytes should catch most usual escaping situations, avoiding a second run in OSMO_NAME_C_IMPL. */
-	OSMO_NAME_C_IMPL(ctx, in_len + 16, "ERROR", _osmo_quote_str_buf, str, in_len);
+	OSMO_NAME_C_IMPL(ctx, in_len + 16, "ERROR", _osmo_quote_str_buf, str, in_len, true);
+}
+
+/*! Return the string with all non-printable characters escaped.
+ * In contrast to osmo_escape_str_buf2(), this returns the needed buffer size suitable for OSMO_STRBUF_APPEND(), and
+ * this escapes characters in a way compatible with C string constant syntax.
+ * \param[out] buf  string buffer to write escaped characters to.
+ * \param[in] bufsize  sizeof(buf).
+ * \param[in] str  A string that may contain any characters.
+ * \param[in] in_len  Pass -1 to print until nul char, or >= 0 to force a length (also past nul chars).
+ * \return Number of characters that would be written if bufsize were large enough excluding '\0' (like snprintf()).
+ */
+size_t osmo_escape_cstr_buf(char *buf, size_t bufsize, const char *str, int in_len)
+{
+	return _osmo_escape_str_buf(buf, bufsize, str, in_len, false);
+}
+
+/*! Return the string with all non-printable characters escaped, in dynamically-allocated buffer.
+ * In contrast to osmo_escape_str_c(), this escapes characters in a way compatible with C string constant syntax, and
+ * allocates sufficient memory in all cases.
+ * \param[in] str  A string that may contain any characters.
+ * \param[in] len  Pass -1 to print until nul char, or >= 0 to force a length.
+ * \returns dynamically-allocated buffer, containing an escaped representation.
+ */
+char *osmo_escape_cstr_c(void *ctx, const char *str, int in_len)
+{
+	/* The string will be at least as long as in_len, but some characters might need escaping.
+	 * These extra bytes should catch most usual escaping situations, avoiding a second run in OSMO_NAME_C_IMPL. */
+	OSMO_NAME_C_IMPL(ctx, in_len + 16, "ERROR", _osmo_escape_str_buf, str, in_len, false);
+}
+
+/*! Like osmo_escape_str_buf2(), but returns double-quotes around a string, or "NULL" for a NULL string.
+ * This allows passing any char* value and get its C representation as string.
+ * The function signature is suitable for OSMO_STRBUF_APPEND_NOLEN().
+ * In contrast to osmo_escape_str_buf2(), this returns the needed buffer size suitable for OSMO_STRBUF_APPEND(), and
+ * this escapes characters in a way compatible with C string constant syntax.
+ * \param[out] buf  string buffer to write escaped characters to.
+ * \param[in] bufsize  sizeof(buf).
+ * \param[in] str  A string that may contain any characters.
+ * \param[in] in_len  Pass -1 to print until nul char, or >= 0 to force a length.
+ * \return Number of characters that would be written if bufsize were large enough excluding '\0' (like snprintf()).
+ */
+size_t osmo_quote_cstr_buf(char *buf, size_t bufsize, const char *str, int in_len)
+{
+	return _osmo_quote_str_buf(buf, bufsize, str, in_len, false);
+}
+
+/*! Return the string quoted and with all non-printable characters escaped, in dynamically-allocated buffer.
+ * In contrast to osmo_quote_str_c(), this escapes characters in a way compatible with C string constant syntax, and
+ * allocates sufficient memory in all cases.
+ * \param[in] str  A string that may contain any characters.
+ * \param[in] len  Pass -1 to print until nul char, or >= 0 to force a length.
+ * \returns dynamically-allocated buffer, containing a quoted and escaped representation.
+ */
+char *osmo_quote_cstr_c(void *ctx, const char *str, int in_len)
+{
+	/* The string will be at least as long as in_len plus two quotes, but some characters might need escaping.
+	 * These extra bytes should catch most usual escaping situations, avoiding a second run in OSMO_NAME_C_IMPL. */
+	OSMO_NAME_C_IMPL(ctx, in_len + 16, "ERROR", _osmo_quote_str_buf, str, in_len, false);
 }
 
 /*! perform an integer square root operation on unsigned 32bit integer.
diff --git a/tests/utils/utils_test.c b/tests/utils/utils_test.c
index a79b8ed1..e87cb22f 100644
--- a/tests/utils/utils_test.c
+++ b/tests/utils/utils_test.c
@@ -531,7 +531,7 @@ static void str_escape_test(void)
 	const char *printable = "printable";
 	const char *res;
 
-	printf("\nTesting string escaping\n");
+	printf("\nTesting string escaping: osmo_escape_str()\n");
 	printf("- all chars from 0 to 255 in batches of 16:\n");
 	in_buf[16] = '\0';
 	for (j = 0; j < 16; j++) {
@@ -571,7 +571,7 @@ static void str_quote_test(void)
 	const char *printable = "printable";
 	const char *res;
 
-	printf("\nTesting string quoting\n");
+	printf("\nTesting string quoting: osmo_quote_str()\n");
 	printf("- all chars from 0 to 255 in batches of 16:\n");
 	in_buf[16] = '\0';
 	for (j = 0; j < 16; j++) {
@@ -616,6 +616,132 @@ static void str_quote_test(void)
 	printf("'%s'\n", osmo_quote_str_buf(NULL, -1, out_buf, 10));
 }
 
+static void str_escape3_test(void)
+{
+	int i;
+	int j;
+	uint8_t in_buf[32];
+	char out_buf[11];
+	const char *printable = "printable";
+	const char *res;
+	void *ctx = talloc_named_const(NULL, 0, __func__);
+
+	printf("\nTesting string escaping: osmo_escape_cstr_buf()\n");
+	printf("- all chars from 0 to 255 in batches of 16:\n");
+	in_buf[16] = '\0';
+	for (j = 0; j < 16; j++) {
+		for (i = 0; i < 16; i++)
+			in_buf[i] = (j << 4) | i;
+		printf("\"%s\"\n", osmo_escape_cstr_c(ctx, (const char*)in_buf, 16));
+	}
+
+	printf("- nul terminated:\n");
+	printf("\"%s\"\n", osmo_escape_cstr_c(ctx, "termi\nated", -1));
+
+	printf("- passthru:\n");
+	res = osmo_escape_cstr_c(ctx, printable, -1);
+	if (strcmp(res, printable))
+		printf("NOT passed through! \"%s\"\n", res);
+	else
+		printf("passed through unchanged \"%s\"\n", res);
+
+	printf("- zero length:\n");
+	printf("\"%s\"\n", osmo_escape_cstr_c(ctx, "omitted", 0));
+
+	printf("- truncation when too long:\n");
+	memset(in_buf, 'x', sizeof(in_buf));
+	in_buf[0] = '\a';
+	in_buf[7] = 'E';
+	memset(out_buf, 0x7f, sizeof(out_buf));
+	osmo_escape_cstr_buf(out_buf, 10, (const char *)in_buf, sizeof(in_buf));
+	printf("\"%s\"\n", out_buf);
+	OSMO_ASSERT(out_buf[10] == 0x7f);
+
+	printf("- Test escaping an escaped string:\n");
+	res = "\x02\x03\n";
+	for (i = 0; i <= 3; i++) {
+		res = osmo_escape_cstr_c(ctx, res, -1);
+		printf("%d: '%s'\n", i, res);
+	}
+
+	talloc_free(ctx);
+}
+
+static void str_quote3_test(void)
+{
+	int i;
+	int j;
+	uint8_t in_buf[32];
+	char out_buf[11];
+	const char *printable = "printable";
+	const char *res;
+	void *ctx = talloc_named_const(NULL, 0, __func__);
+
+	printf("\nTesting string quoting: osmo_quote_cstr_buf()\n");
+	printf("- all chars from 0 to 255 in batches of 16:\n");
+	in_buf[16] = '\0';
+	for (j = 0; j < 16; j++) {
+		for (i = 0; i < 16; i++)
+			in_buf[i] = (j << 4) | i;
+		printf("%s\n", osmo_quote_cstr_c(ctx, (const char*)in_buf, 16));
+	}
+
+	printf("- nul terminated:\n");
+	printf("'%s'\n", osmo_quote_cstr_c(ctx, "termi\nated", -1));
+
+	printf("- never passthru:\n");
+	res = osmo_quote_cstr_c(ctx, printable, -1);
+	if (strcmp(res, printable))
+		printf("NOT passed through. '%s'\n", res);
+	else
+		printf("passed through unchanged '%s'\n", res);
+
+	printf("- zero length:\n");
+	printf("'%s'\n", osmo_quote_cstr_c(ctx, "omitted", 0));
+
+	printf("- truncation when too long:\n");
+	memset(in_buf, 'x', sizeof(in_buf));
+	in_buf[0] = '\a';
+	in_buf[6] = 'E';
+	memset(out_buf, 0x7f, sizeof(out_buf));
+	osmo_quote_cstr_buf(out_buf, 10, (const char *)in_buf, sizeof(in_buf));
+	printf("'%s'\n", out_buf);
+	OSMO_ASSERT(out_buf[10] == 0x7f);
+
+	printf("- always truncation, even when no escaping needed:\n");
+	memset(in_buf, 'x', sizeof(in_buf));
+	in_buf[7] = 'E'; /* dst has 10, less 1 quote and nul, leaves 8, i.e. in[7] is last */
+	in_buf[20] = '\0';
+	memset(out_buf, 0x7f, sizeof(out_buf));
+	osmo_quote_cstr_buf(out_buf, 10, (const char *)in_buf, -1);
+	printf("'%s'\n", out_buf);
+	OSMO_ASSERT(out_buf[0] == '"');
+	OSMO_ASSERT(out_buf[10] == 0x7f);
+
+	printf("- try to feed too little buf for quoting:\n");
+	osmo_quote_cstr_buf(out_buf, 2, "", -1);
+	printf("'%s'\n", out_buf);
+
+	printf("- Test quoting a quoted+escaped string:\n");
+	res = "\x02\x03\n";
+	for (i = 0; i <= 3; i++) {
+		res = osmo_quote_cstr_c(ctx, res, -1);
+		printf("%d: %s\n", i, res);
+	}
+
+	printf("- Test C-string equivalence:\n");
+#define TEST_STR "\0\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"
+#define EMPTY_STR ""
+	printf("strcmp(OSMO_STRINGIFY_VAL(TEST_STR), osmo_quote_cstr_c(ctx, TEST_STR, 256)) == %d\n",
+	       strcmp(OSMO_STRINGIFY_VAL(TEST_STR), osmo_quote_cstr_c(ctx, TEST_STR, 256)));
+	printf("strcmp(OSMO_STRINGIFY_VAL(EMPTY_STR), osmo_quote_cstr_c(ctx, EMPTY_STR, -1)) == %d\n",
+	       strcmp(OSMO_STRINGIFY_VAL(EMPTY_STR), osmo_quote_cstr_c(ctx, EMPTY_STR, -1)));
+	printf("strcmp(\"NULL\", osmo_quote_cstr_c(ctx, NULL, -1)) == %d\n",
+	       strcmp("NULL", osmo_quote_cstr_c(ctx, NULL, -1)));
+
+	talloc_free(ctx);
+}
+
 static void isqrt_test(void)
 {
 	int i;
@@ -1238,6 +1364,8 @@ int main(int argc, char **argv)
 	bcd2str_test();
 	str_escape_test();
 	str_quote_test();
+	str_escape3_test();
+	str_quote3_test();
 	isqrt_test();
 	osmo_sockaddr_to_str_and_uint_test();
 	osmo_str_tolowupper_test();
diff --git a/tests/utils/utils_test.ok b/tests/utils/utils_test.ok
index 89e0fed4..baa708ee 100644
--- a/tests/utils/utils_test.ok
+++ b/tests/utils/utils_test.ok
@@ -206,7 +206,7 @@ Testing bcd to string conversion
   bcd2str(NULL, ...) -> -12
   bcd2str(dst, 0, ...) -> -12
 
-Testing string escaping
+Testing string escaping: osmo_escape_str()
 - all chars from 0 to 255 in batches of 16:
 "\0\1\2\3\4\5\6\a\b\t\n\v\f\r\14\15"
 "\16\17\18\19\20\21\22\23\24\25\26\27\28\29\30\31"
@@ -233,7 +233,7 @@ passed through unchanged "printable"
 - truncation when too long:
 "\axxxxxxE"
 
-Testing string quoting
+Testing string quoting: osmo_quote_str()
 - all chars from 0 to 255 in batches of 16:
 '"\0\1\2\3\4\5\6\a\b\t\n\v\f\r\14\15"'
 '"\16\17\18\19\20\21\22\23\24\25\26\27\28\29\30\31"'
@@ -266,6 +266,78 @@ NOT passed through. '"printable"'
 - NULL string becomes a "NULL" literal:
 'NULL'
 
+Testing string escaping: osmo_escape_cstr_buf()
+- all chars from 0 to 255 in batches of 16:
+"\0\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f"
+"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
+" !\"#$%&'()*+,-./"
+"0123456789:;<=>?"
+"@ABCDEFGHIJKLMNO"
+"PQRSTUVWXYZ[\\]^_"
+"`abcdefghijklmno"
+"pqrstuvwxyz{|}~\x7f"
+"\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
+"\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f"
+"\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf"
+"\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf"
+"\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf"
+"\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf"
+"\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef"
+"\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"
+- nul terminated:
+"termi\nated"
+- passthru:
+passed through unchanged "printable"
+- zero length:
+""
+- truncation when too long:
+"\x07xxxxx"
+- Test escaping an escaped string:
+0: '\x02\x03\n'
+1: '\\x02\\x03\\n'
+2: '\\\\x02\\\\x03\\\\n'
+3: '\\\\\\\\x02\\\\\\\\x03\\\\\\\\n'
+
+Testing string quoting: osmo_quote_cstr_buf()
+- all chars from 0 to 255 in batches of 16:
+"\0\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f"
+"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
+" !\"#$%&'()*+,-./"
+"0123456789:;<=>?"
+"@ABCDEFGHIJKLMNO"
+"PQRSTUVWXYZ[\\]^_"
+"`abcdefghijklmno"
+"pqrstuvwxyz{|}~\x7f"
+"\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
+"\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f"
+"\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf"
+"\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf"
+"\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf"
+"\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf"
+"\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef"
+"\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff"
+- nul terminated:
+'"termi\nated"'
+- never passthru:
+NOT passed through. '"printable"'
+- zero length:
+'""'
+- truncation when too long:
+'"\x07xxxx'
+- always truncation, even when no escaping needed:
+'"xxxxxxxE'
+- try to feed too little buf for quoting:
+'"'
+- Test quoting a quoted+escaped string:
+0: "\x02\x03\n"
+1: "\"\\x02\\x03\\n\""
+2: "\"\\\"\\\\x02\\\\x03\\\\n\\\"\""
+3: "\"\\\"\\\\\\\"\\\\\\\\x02\\\\\\\\x03\\\\\\\\n\\\\\\\"\\\"\""
+- Test C-string equivalence:
+strcmp(OSMO_STRINGIFY_VAL(TEST_STR), osmo_quote_cstr_c(ctx, TEST_STR, 256)) == 0
+strcmp(OSMO_STRINGIFY_VAL(EMPTY_STR), osmo_quote_cstr_c(ctx, EMPTY_STR, -1)) == 0
+strcmp("NULL", osmo_quote_cstr_c(ctx, NULL, -1)) == 0
+
 Testing integer square-root
 
 osmo_sockaddr_to_str_and_uint_test