From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
To: linux-kernel@vger.kernel.org
Cc: Tejun Heo <tj@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Alexey Dobriyan <adobriyan@gmail.com>
Subject: [PATCH v1 4/6] lib: scanf: handle character ranges in %[...]
Date: Sun, 10 Mar 2019 19:56:36 +0300 [thread overview]
Message-ID: <155223699650.4075.16018050078707979118.stgit@buzz> (raw)
In-Reply-To: <155223448227.4075.6846910559654700796.stgit@buzz>
Complete implementation isn't much bigger than present one.
This patch adds missing standard features:
%[a-z] - matches 'a'..'z'
%[][] - matches '[' and ']' (']' must be first)
%[_-] - matches '_' and '-' ('-' must be last)
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
lib/vsprintf.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 66debf42387a..5c27c5d18d4e 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -3019,7 +3019,6 @@ EXPORT_SYMBOL_GPL(bprintf);
* - memory-allocation "%m..."
* - pointer "%p", ptrdiff_t "%t...", intmax_t "%j..."
* - discaring of matching input "%*[...]"
- * - ranges or matching ']' in "%[...]"
* - positional assignment "%n$"
*
* Non-standatd features:
@@ -3160,11 +3159,8 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
/*
* Warning: This implementation of the '[' conversion specifier
* deviates from its glibc counterpart in the following ways:
- * (1) It does NOT support ranges i.e. '-' is NOT a special
- * character
- * (2) It cannot match the closing bracket ']' itself
- * (3) A field width is required
- * (4) '%*[' (discard matching input) is currently not supported
+ * (1) A field width is required
+ * (2) '%*[' (discard matching input) is currently not supported
*
* Example usage:
* ret = sscanf("00:0a:95","%2[^:]:%2[^:]:%2[^:]",
@@ -3176,7 +3172,6 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
{
char *s = (char *)va_arg(args, char *);
DECLARE_BITMAP(set, 256) = {0};
- unsigned int len = 0;
bool negate = (*fmt == '^');
/* field width is required */
@@ -3186,12 +3181,25 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
if (negate)
++fmt;
- for ( ; *fmt && *fmt != ']'; ++fmt, ++len)
- set_bit((u8)*fmt, set);
+ do {
+ /* no ']' found */
+ if (!*fmt)
+ return num;
- /* no ']' or no character set found */
- if (!*fmt || !len)
- return num;
+ /* '-' at last position is non-special */
+ if (*fmt == '-' && *(fmt + 1) != ']') {
+ u8 a = *(fmt - 1);
+ u8 b = *(fmt + 1);
+
+ if (a <= b)
+ bitmap_set(set, a, b - a + 1);
+ } else
+ set_bit((u8)*fmt, set);
+
+ /* ']' at first position is non-special */
+ } while (*++fmt != ']');
+
+ /* skip ']' */
++fmt;
if (negate) {
next prev parent reply other threads:[~2019-03-10 16:56 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-10 16:56 [PATCH v1 0/6] Make sscanf safer Konstantin Khlebnikov
2019-03-10 16:56 ` [PATCH v1 1/6] lib: scanf: document features of scanf format string Konstantin Khlebnikov
2019-03-10 16:56 ` [PATCH v1 2/6] lib: scanf: handle integer overflows in vsscanf Konstantin Khlebnikov
2019-03-10 21:06 ` Rasmus Villemoes
2019-03-10 21:52 ` Linus Torvalds
2019-03-11 7:22 ` Konstantin Khlebnikov
2019-03-10 16:56 ` [PATCH v1 3/6] lib: scanf: add vsscanf feature for matching end of text Konstantin Khlebnikov
2019-03-10 16:56 ` Konstantin Khlebnikov [this message]
2019-03-10 16:56 ` [PATCH v1 5/6] lib: scanf: mark sscanf and vsscanf as __must_check Konstantin Khlebnikov
2019-03-10 16:56 ` [PATCH v1 6/6] lib: scanf: add test module Konstantin Khlebnikov
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