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-rw-r--r--lib/string_helpers.c193
1 files changed, 80 insertions, 113 deletions
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 8f8c4417f228..1826c7407258 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -239,29 +239,21 @@ int string_unescape(char *src, char *dst, size_t size, unsigned int flags)
}
EXPORT_SYMBOL(string_unescape);
-static int escape_passthrough(unsigned char c, char **dst, size_t *osz)
+static bool escape_passthrough(unsigned char c, char **dst, char *end)
{
char *out = *dst;
- if (*osz < 1)
- return -ENOMEM;
-
- *out++ = c;
-
- *dst = out;
- *osz -= 1;
-
- return 1;
+ if (out < end)
+ *out = c;
+ *dst = out + 1;
+ return true;
}
-static int escape_space(unsigned char c, char **dst, size_t *osz)
+static bool escape_space(unsigned char c, char **dst, char *end)
{
char *out = *dst;
unsigned char to;
- if (*osz < 2)
- return -ENOMEM;
-
switch (c) {
case '\n':
to = 'n';
@@ -279,26 +271,25 @@ static int escape_space(unsigned char c, char **dst, size_t *osz)
to = 'f';
break;
default:
- return 0;
+ return false;
}
- *out++ = '\\';
- *out++ = to;
+ if (out < end)
+ *out = '\\';
+ ++out;
+ if (out < end)
+ *out = to;
+ ++out;
*dst = out;
- *osz -= 2;
-
- return 1;
+ return true;
}
-static int escape_special(unsigned char c, char **dst, size_t *osz)
+static bool escape_special(unsigned char c, char **dst, char *end)
{
char *out = *dst;
unsigned char to;
- if (*osz < 2)
- return -ENOMEM;
-
switch (c) {
case '\\':
to = '\\';
@@ -310,71 +301,78 @@ static int escape_special(unsigned char c, char **dst, size_t *osz)
to = 'e';
break;
default:
- return 0;
+ return false;
}
- *out++ = '\\';
- *out++ = to;
+ if (out < end)
+ *out = '\\';
+ ++out;
+ if (out < end)
+ *out = to;
+ ++out;
*dst = out;
- *osz -= 2;
-
- return 1;
+ return true;
}
-static int escape_null(unsigned char c, char **dst, size_t *osz)
+static bool escape_null(unsigned char c, char **dst, char *end)
{
char *out = *dst;
- if (*osz < 2)
- return -ENOMEM;
-
if (c)
- return 0;
+ return false;
- *out++ = '\\';
- *out++ = '0';
+ if (out < end)
+ *out = '\\';
+ ++out;
+ if (out < end)
+ *out = '0';
+ ++out;
*dst = out;
- *osz -= 2;
-
- return 1;
+ return true;
}
-static int escape_octal(unsigned char c, char **dst, size_t *osz)
+static bool escape_octal(unsigned char c, char **dst, char *end)
{
char *out = *dst;
- if (*osz < 4)
- return -ENOMEM;
-
- *out++ = '\\';
- *out++ = ((c >> 6) & 0x07) + '0';
- *out++ = ((c >> 3) & 0x07) + '0';
- *out++ = ((c >> 0) & 0x07) + '0';
+ if (out < end)
+ *out = '\\';
+ ++out;
+ if (out < end)
+ *out = ((c >> 6) & 0x07) + '0';
+ ++out;
+ if (out < end)
+ *out = ((c >> 3) & 0x07) + '0';
+ ++out;
+ if (out < end)
+ *out = ((c >> 0) & 0x07) + '0';
+ ++out;
*dst = out;
- *osz -= 4;
-
- return 1;
+ return true;
}
-static int escape_hex(unsigned char c, char **dst, size_t *osz)
+static bool escape_hex(unsigned char c, char **dst, char *end)
{
char *out = *dst;
- if (*osz < 4)
- return -ENOMEM;
-
- *out++ = '\\';
- *out++ = 'x';
- *out++ = hex_asc_hi(c);
- *out++ = hex_asc_lo(c);
+ if (out < end)
+ *out = '\\';
+ ++out;
+ if (out < end)
+ *out = 'x';
+ ++out;
+ if (out < end)
+ *out = hex_asc_hi(c);
+ ++out;
+ if (out < end)
+ *out = hex_asc_lo(c);
+ ++out;
*dst = out;
- *osz -= 4;
-
- return 1;
+ return true;
}
/**
@@ -426,19 +424,17 @@ static int escape_hex(unsigned char c, char **dst, size_t *osz)
* it if needs.
*
* Return:
- * The amount of the characters processed to the destination buffer, or
- * %-ENOMEM if the size of buffer is not enough to put an escaped character is
- * returned.
- *
- * Even in the case of error @dst pointer will be updated to point to the byte
- * after the last processed character.
+ * The total size of the escaped output that would be generated for
+ * the given input and flags. To check whether the output was
+ * truncated, compare the return value to osz. There is room left in
+ * dst for a '\0' terminator if and only if ret < osz.
*/
-int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
+int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
unsigned int flags, const char *esc)
{
- char *out = *dst, *p = out;
+ char *p = dst;
+ char *end = p + osz;
bool is_dict = esc && *esc;
- int ret = 0;
while (isz--) {
unsigned char c = *src++;
@@ -458,55 +454,26 @@ int string_escape_mem(const char *src, size_t isz, char **dst, size_t osz,
(is_dict && !strchr(esc, c))) {
/* do nothing */
} else {
- if (flags & ESCAPE_SPACE) {
- ret = escape_space(c, &p, &osz);
- if (ret < 0)
- break;
- if (ret > 0)
- continue;
- }
-
- if (flags & ESCAPE_SPECIAL) {
- ret = escape_special(c, &p, &osz);
- if (ret < 0)
- break;
- if (ret > 0)
- continue;
- }
-
- if (flags & ESCAPE_NULL) {
- ret = escape_null(c, &p, &osz);
- if (ret < 0)
- break;
- if (ret > 0)
- continue;
- }
+ if (flags & ESCAPE_SPACE && escape_space(c, &p, end))
+ continue;
+
+ if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end))
+ continue;
+
+ if (flags & ESCAPE_NULL && escape_null(c, &p, end))
+ continue;
/* ESCAPE_OCTAL and ESCAPE_HEX always go last */
- if (flags & ESCAPE_OCTAL) {
- ret = escape_octal(c, &p, &osz);
- if (ret < 0)
- break;
+ if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end))
continue;
- }
- if (flags & ESCAPE_HEX) {
- ret = escape_hex(c, &p, &osz);
- if (ret < 0)
- break;
+
+ if (flags & ESCAPE_HEX && escape_hex(c, &p, end))
continue;
- }
}
- ret = escape_passthrough(c, &p, &osz);
- if (ret < 0)
- break;
+ escape_passthrough(c, &p, end);
}
- *dst = p;
-
- if (ret < 0)
- return ret;
-
- return p - out;
+ return p - dst;
}
EXPORT_SYMBOL(string_escape_mem);
generated by cgit (git 2.34.1) at 2024-06-08 13:52:50 +0000