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-rw-r--r--lib/string_helpers.c208
1 files changed, 105 insertions, 103 deletions
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 8f8c4417f228..9c48ddad0f0d 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 +271,30 @@ 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 + 2 > end) {
+ *dst = out + 2;
+ return true;
+ }
- *dst = out;
- *osz -= 2;
+ if (out < end)
+ *out = '\\';
+ ++out;
+ if (out < end)
+ *out = to;
+ ++out;
- return 1;
+ *dst = out;
+ 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 +306,98 @@ 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 + 2 > end) {
+ *dst = out + 2;
+ return true;
+ }
- *dst = out;
- *osz -= 2;
+ if (out < end)
+ *out = '\\';
+ ++out;
+ if (out < end)
+ *out = to;
+ ++out;
- return 1;
+ *dst = out;
+ 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 + 2 > end) {
+ *dst = out + 2;
+ return true;
+ }
- *dst = out;
- *osz -= 2;
+ if (out < end)
+ *out = '\\';
+ ++out;
+ if (out < end)
+ *out = '0';
+ ++out;
- return 1;
+ *dst = out;
+ 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;
+ if (out + 4 > end) {
+ *dst = out + 4;
+ return true;
+ }
- *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;
+ if (out + 4 > end) {
+ *dst = out + 4;
+ return true;
+ }
- *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;
}
/**
@@ -436,9 +459,10 @@ static int escape_hex(unsigned char c, 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;
+ int ret;
while (isz--) {
unsigned char c = *src++;
@@ -458,55 +482,33 @@ 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;
+ if (p > end) {
+ *dst = end;
+ return -ENOMEM;
+ }
- return p - out;
+ ret = p - *dst;
+ *dst = p;
+ return ret;
}
EXPORT_SYMBOL(string_escape_mem);