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Subject[PATCH 6/9] Eliminate unused ESCAPE_NULL, ESCAPE_SPACE flags
Date
From: "J. Bruce Fields" <bfields@redhat.com>

I can see how some finer-grained flags could be useful, but for now I'm
trying to simplify, so let's just remove these unused ones.

Note the trickiest part is actually the tests, and I still need to check
them.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
---
fs/proc/array.c | 2 +-
include/linux/string_helpers.h | 6 ++--
lib/string_helpers.c | 54 +++----------------------------
lib/test-string_helpers.c | 58 ++++------------------------------
4 files changed, 14 insertions(+), 106 deletions(-)

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 46dcb6f0eccf..982c95d09176 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -111,7 +111,7 @@ void proc_task_name(struct seq_file *m, struct task_struct *p, bool escape)
size = seq_get_buf(m, &buf);
if (escape) {
ret = string_escape_str(tcomm, buf, size,
- ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
+ ESCAPE_SPECIAL, "\n\\");
if (ret >= size)
ret = -1;
} else {
diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index 8a299a29b767..7bf0d137373d 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -41,15 +41,13 @@ static inline int string_unescape_any_inplace(char *buf)
return string_unescape_any(buf, buf, 0);
}

-#define ESCAPE_SPACE 0x01
#define ESCAPE_SPECIAL 0x02
-#define ESCAPE_NULL 0x04
#define ESCAPE_OCTAL 0x08
-#define ESCAPE_ANY \
- (ESCAPE_SPACE | ESCAPE_OCTAL | ESCAPE_SPECIAL | ESCAPE_NULL)
+#define ESCAPE_ANY (ESCAPE_OCTAL | ESCAPE_SPECIAL)
#define ESCAPE_NP 0x10
#define ESCAPE_ANY_NP (ESCAPE_ANY | ESCAPE_NP)
#define ESCAPE_HEX 0x20
+#define ESCAPE_FLAG_MASK 0x3a

int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
unsigned int flags, const char *only);
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 963050c0283e..ac72159d3980 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -310,7 +310,7 @@ static bool escape_passthrough(unsigned char c, char **dst, char *end)
return true;
}

-static bool escape_space(unsigned char c, char **dst, char *end)
+static bool escape_special(unsigned char c, char **dst, char *end)
{
char *out = *dst;
unsigned char to;
@@ -331,27 +331,6 @@ static bool escape_space(unsigned char c, char **dst, char *end)
case '\f':
to = 'f';
break;
- default:
- return false;
- }
-
- if (out < end)
- *out = '\\';
- ++out;
- if (out < end)
- *out = to;
- ++out;
-
- *dst = out;
- return true;
-}
-
-static bool escape_special(unsigned char c, char **dst, char *end)
-{
- char *out = *dst;
- unsigned char to;
-
- switch (c) {
case '\\':
to = '\\';
break;
@@ -361,6 +340,9 @@ static bool escape_special(unsigned char c, char **dst, char *end)
case '\e':
to = 'e';
break;
+ case '\0':
+ to = '0';
+ break;
default:
return false;
}
@@ -376,24 +358,6 @@ static bool escape_special(unsigned char c, char **dst, char *end)
return true;
}

-static bool escape_null(unsigned char c, char **dst, char *end)
-{
- char *out = *dst;
-
- if (c)
- return false;
-
- if (out < end)
- *out = '\\';
- ++out;
- if (out < end)
- *out = '0';
- ++out;
-
- *dst = out;
- return true;
-}
-
static bool escape_octal(unsigned char c, char **dst, char *end)
{
char *out = *dst;
@@ -465,17 +429,15 @@ static bool escape_hex(unsigned char c, char **dst, char *end)
* destination buffer will not be NULL-terminated, thus caller have to append
* it if needs. The supported flags are::
*
- * %ESCAPE_SPACE: (special white space, not space itself)
+ * %ESCAPE_SPECIAL:
* '\f' - form feed
* '\n' - new line
* '\r' - carriage return
* '\t' - horizontal tab
* '\v' - vertical tab
- * %ESCAPE_SPECIAL:
* '\\' - backslash
* '\a' - alert (BEL)
* '\e' - escape
- * %ESCAPE_NULL:
* '\0' - null
* %ESCAPE_OCTAL:
* '\NNN' - byte with octal value NNN (3 digits)
@@ -519,15 +481,9 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
(is_dict && !strchr(only, c))) {
/* do nothing */
} else {
- 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 && escape_octal(c, &p, end))
continue;
diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c
index 25b5cbfb7615..0da3c195a327 100644
--- a/lib/test-string_helpers.c
+++ b/lib/test-string_helpers.c
@@ -124,20 +124,6 @@ struct test_string_2 {

#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\\\\",
@@ -154,48 +140,26 @@ static const struct test_string_2 escape0[] __initconst = {{
},{
.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,
+ .flags = 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,
+ .flags = 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,
+ .flags = 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,
+ .flags = ESCAPE_SPECIAL ESCAPE_OCTAL | ESCAPE_NP,
},{
.out = "\\x1bb \\C\\x07\"\\x90\\x0d]",
.flags = ESCAPE_NP | ESCAPE_HEX,
@@ -247,9 +211,6 @@ static __init const char *test_string_find_match(const struct test_string_2 *s2,
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;
@@ -290,13 +251,6 @@ static __init void test_string_escape(const char *name,
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)
@@ -401,11 +355,11 @@ static int __init test_string_helpers_init(void)
get_random_int() % (UNESCAPE_ANY + 1), true);

/* Without dictionary */
- for (i = 0; i < (ESCAPE_ANY_NP | ESCAPE_HEX) + 1; i++)
+ for (i = 0; i < ESCAPE_FLAG_MASK + 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++)
+ for (i = 0; i < ESCAPE_FLAG_MASK + 1; i++)
test_string_escape("escape 1", escape1, i, TEST_STRING_2_DICT_1);

/* Test string_get_size() */
--
2.21.0
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