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
diff --git a/src/utils.c b/src/utils.c
index c3e3efb..038288c 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -693,14 +693,18 @@
/*! 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 @@
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 @@
*/
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 @@
{
/* 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 @@
*/
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 @@
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(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 @@
{
/* 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.