From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Trond Myklebust <trond.myklebust@primarydata.com>,
"J. Bruce Fields" <bfields@fieldses.org>,
"David S. Miller" <davem@davemloft.net>,
linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org,
netdev@vger.kernel.org
Subject: Re: [PATCH v2 3/3] lib/string_helpers.c: Change semantics of string_escape_mem
Date: Mon, 02 Feb 2015 12:56:37 +0200 [thread overview]
Message-ID: <1422874597.31903.358.camel@linux.intel.com> (raw)
In-Reply-To: <87pp9vhm8l.fsf@rasmusvillemoes.dk>
On Sat, 2015-01-31 at 00:39 +0100, Rasmus Villemoes wrote:
> On Fri, Jan 30 2015, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> >> >> * 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,
> >> >> - unsigned int flags, const char *esc)
> >> >> +size_t string_escape_mem(const char *src, size_t isz, char *dst, size_t osz,
> >> >> + unsigned int flags, const char *esc)
> >> >
> >> > I prefer to leave the prototype the same. int for return is okay. dst
> >> > should be updated accordingly.
> >>
> >> Please explain exactly what you think the return value should be, and
> >> what *dst should be set to.
> >
> > Return value like you proposed, *dst is incremented by it.
>
> The more I think about it, the less I like having dst being char**.
>
> (1) It is unlike most other functions taking buffer+size arguments.
> (2) It is inconvenient. Callers doing
>
> char escaped[SOME_SIZE];
>
> or
>
> char *escaped = kmalloc(likely_big_enough);
>
> can't just pass &escaped; they would need to use an extra dummy variable.
>
> (3) With the return value telling the size of the would-be generated
> output, it is redundant.
>
> In fact, I dislike it so much that I'm not going to sign off on a patch
> where dst is still char**.
Fair enough, though there usual case when temporary variable is already
present (at least current users).
Let's proceed with char *dst.
--
Andy Shevchenko <andriy.shevchenko@intel.com>
Intel Finland Oy
next prev parent reply other threads:[~2015-02-02 10:56 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-28 13:25 [PATCH 0/2] Two printf fixes Rasmus Villemoes
2015-01-28 13:25 ` [PATCH 1/2] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-01-28 14:53 ` Andy Shevchenko
2015-01-28 15:49 ` Rasmus Villemoes
2015-01-28 16:43 ` Andy Shevchenko
2015-01-28 13:25 ` [PATCH 2/2] string_helpers: Change semantics of string_escape_mem Rasmus Villemoes
2015-01-28 15:05 ` Andy Shevchenko
2015-01-29 10:03 ` [PATCH v2 0/3] Two printf fixes Rasmus Villemoes
2015-01-29 10:03 ` [PATCH v2 1/3] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-01-29 10:43 ` Andy Shevchenko
2015-01-29 10:03 ` [PATCH v2 2/3] lib/string_helpers.c: Refactor string_escape_mem Rasmus Villemoes
2015-01-29 12:12 ` Andy Shevchenko
2015-01-29 13:10 ` Rasmus Villemoes
2015-01-29 13:37 ` Andy Shevchenko
2015-01-29 19:33 ` Jeff Epler
2015-01-30 10:14 ` Andy Shevchenko
2015-01-29 10:03 ` [PATCH v2 3/3] lib/string_helpers.c: Change semantics of string_escape_mem Rasmus Villemoes
2015-01-29 13:29 ` Andy Shevchenko
2015-01-29 14:29 ` Rasmus Villemoes
2015-01-30 10:27 ` Andy Shevchenko
2015-01-30 23:39 ` Rasmus Villemoes
2015-02-02 10:56 ` Andy Shevchenko [this message]
2015-02-09 23:44 ` [PATCH v3 0/3] Two printf fixes Rasmus Villemoes
2015-02-09 23:44 ` [PATCH v3 1/3] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-02-09 23:44 ` [PATCH v3 2/3] lib/string_helpers.c: Refactor string_escape_mem Rasmus Villemoes
2015-02-10 12:16 ` Andy Shevchenko
2015-02-09 23:44 ` [PATCH v3 3/3] lib/string_helpers.c: Change semantics of string_escape_mem Rasmus Villemoes
2015-02-10 12:32 ` Andy Shevchenko
2015-02-10 13:02 ` Rasmus Villemoes
2015-02-10 14:22 ` Andy Shevchenko
2015-02-21 1:35 ` Rasmus Villemoes
2015-02-23 12:50 ` Andy Shevchenko
2015-02-23 22:55 ` Rasmus Villemoes
2015-03-02 12:37 ` Andy Shevchenko
2015-03-02 23:03 ` Rasmus Villemoes
2015-03-03 10:26 ` Andy Shevchenko
2015-03-03 23:20 ` [PATCH v4 0/3] Two printf fixes Rasmus Villemoes
2015-03-03 23:20 ` [PATCH v4 1/3] lib/vsprintf.c: Fix potential NULL deref in hex_string Rasmus Villemoes
2015-03-03 23:20 ` [PATCH v4 2/3] lib/string_helpers.c: Refactor string_escape_mem Rasmus Villemoes
2015-03-04 10:51 ` Andy Shevchenko
2015-03-03 23:20 ` [PATCH v4 3/3] lib/string_helpers.c: Change semantics of string_escape_mem Rasmus Villemoes
2015-03-04 11:49 ` Andy Shevchenko
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