From: Philipp Stephani <p.stephani2@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 30005@debbugs.gnu.org
Subject: bug#30005: 27.0.50; call-interactively doesn't work correctly if the interactive specification has an embedded null byte
Date: Mon, 22 Jan 2018 22:25:39 +0000 [thread overview]
Message-ID: <CAArVCkR4NiBPfwaAs2e=SL8Fmws3t=uFumhRssNDH2o=kDtLJg@mail.gmail.com> (raw)
In-Reply-To: <83y3ksspp9.fsf@gnu.org>
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Eli Zaretskii <eliz@gnu.org> schrieb am Sa., 20. Jan. 2018 um 13:03 Uhr:
> > From: Philipp <p.stephani2@gmail.com>
> > Date: Sat, 06 Jan 2018 12:39:43 +0100
> >
> > (call-interactively (lambda (a b) (interactive "sa\0b\ns")))
> >
> > the prompt is only "a" and a `wrong-number-of-argument' signal is
> > raised. This is because `call-interactively' copies the interactive
> > specification to a C string, ignoring embedded nulls.
>
> No, it copies the spec in its entirety, including embedded null bytes,
> but then _processes_ the result as a C string, taking the first null
> byte as the end of the string.
>
> Does the patch below look right, and give good results?
>
Yes, thanks. Just some minor nits inline to make the code shorter.
>
> diff --git a/src/callint.c b/src/callint.c
> index 2253cdf..3d2ed00 100644
> --- a/src/callint.c
> +++ b/src/callint.c
> @@ -288,7 +288,8 @@ invoke it. If KEYS is omitted or nil, the return
> value of
> ptrdiff_t next_event;
>
> Lisp_Object prefix_arg;
> - char *string;
> + char *string, *string_end;
> + ptrdiff_t string_len;
>
I think these days (where we require C99) we always declare variables when
we first use them.
> const char *tem;
>
> /* If varies[i] > 0, the i'th argument shouldn't just have its value
> @@ -396,6 +397,8 @@ invoke it. If KEYS is omitted or nil, the return
> value of
> /* SPECS is set to a string; use it as an interactive prompt.
> Copy it so that STRING will be valid even if a GC relocates SPECS.
> */
> SAFE_ALLOCA_STRING (string, specs);
> + string_len = SBYTES (specs);
> + string_end = string + string_len;
>
> /* Here if function specifies a string to control parsing the
> defaults. */
>
> @@ -418,7 +421,7 @@ invoke it. If KEYS is omitted or nil, the return
> value of
> if (!NILP (record_flag))
> {
> char *p = string;
> - while (*p)
> + while (p < string_end)
> {
> if (! (*p == 'r' || *p == 'p' || *p == 'P'
> || *p == '\n'))
> @@ -469,7 +472,7 @@ invoke it. If KEYS is omitted or nil, the return
> value of
> `funcall-interactively') plus the number of arguments the
> interactive spec
> would have us give to the function. */
> tem = string;
> - for (nargs = 2; *tem; )
> + for (nargs = 2; tem < string_end; )
> {
> /* 'r' specifications ("point and mark as 2 numeric args")
> produce *two* arguments. */
> @@ -477,7 +480,7 @@ invoke it. If KEYS is omitted or nil, the return
> value of
> nargs += 2;
> else
> nargs++;
> - tem = strchr (tem, '\n');
> + tem = memchr (tem, '\n', string_len - (tem - string));
>
You can write the third argument as string_end - tem.
> if (tem)
> ++tem;
> else
> @@ -503,9 +506,12 @@ invoke it. If KEYS is omitted or nil, the return
> value of
> specbind (Qenable_recursive_minibuffers, Qt);
>
> tem = string;
> - for (i = 2; *tem; i++)
> + for (i = 2; tem < string_end; i++)
> {
> - visargs[1] = make_string (tem + 1, strcspn (tem + 1, "\n"));
> + char *pnl = memchr (tem + 1, '\n', string_len - (tem + 1 - string));
>
Here you can write the third argument as string_end - (tem + 1).
> + ptrdiff_t sz = pnl ? pnl - (tem + 1) : string_end - (tem + 1);
>
You can write the RHS as (pnl ? pnl : string_end) - (tem + 1).
> +
> + visargs[1] = make_string (tem + 1, sz);
> callint_message = Fformat_message (i - 1, visargs + 1);
>
> switch (*tem)
> @@ -781,7 +787,7 @@ invoke it. If KEYS is omitted or nil, the return
> value of
> {
> /* How many bytes are left unprocessed in the specs string?
> (Note that this excludes the trailing null byte.) */
> - ptrdiff_t bytes_left = SBYTES (specs) - (tem - string);
> + ptrdiff_t bytes_left = string_len - (tem - string);
>
Same (string-end - tem).
> unsigned letter;
>
> /* If we have enough bytes left to treat the sequence as a
> @@ -803,9 +809,9 @@ invoke it. If KEYS is omitted or nil, the return
> value of
> if (NILP (visargs[i]) && STRINGP (args[i]))
> visargs[i] = args[i];
>
> - tem = strchr (tem, '\n');
> + tem = memchr (tem, '\n', string_len - (tem - string));
>
again, string_end - tem.
> if (tem) tem++;
> - else tem = "";
> + else tem = string_end;
> }
> unbind_to (speccount, Qnil);
>
>
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next prev parent reply other threads:[~2018-01-22 22:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-06 11:39 bug#30005: 27.0.50; call-interactively doesn't work correctly if the interactive specification has an embedded null byte Philipp
2018-01-20 12:02 ` Eli Zaretskii
2018-01-22 22:25 ` Philipp Stephani [this message]
2018-01-23 15:55 ` Eli Zaretskii
2018-01-23 18:06 ` Richard Stallman
2018-02-03 21:48 ` Noam Postavsky
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