From: Noam Postavsky <npostavs@gmail.com>
To: Katsumi Yamaoka <yamaoka@jpl.org>
Cc: Kevin Ryde <user42_kevin@yahoo.com.au>, 33133@debbugs.gnu.org
Subject: bug#33133: 26.1.50; zlib-decompress-region too rigid
Date: Sat, 27 Oct 2018 17:48:26 -0400 [thread overview]
Message-ID: <87efcbjc2d.fsf@gmail.com> (raw)
In-Reply-To: <b4mpnw0qh3z.fsf@jpl.org> (Katsumi Yamaoka's message of "Wed, 24 Oct 2018 10:16:16 +0900")
[-- Attachment #1: Type: text/plain, Size: 608 bytes --]
tags 33133 + patch
quit
Katsumi Yamaoka <yamaoka@jpl.org> writes:
> On Tue, 23 Oct 2018 20:26:59 -0400, Noam Postavsky wrote:
>> --- i/src/decompress.c
>> +++ w/src/decompress.c
>> @@ -206,7 +206,7 @@ DEFUN ("zlib-decompress-region", Fzlib_decompress_region,
>
>> while (inflate_status == Z_OK);
>
>> - if (inflate_status != Z_STREAM_END)
>> + if (inflate_status != Z_STREAM_END && inflate_status != Z_BUF_ERROR)
>> return unbind_to (count, Qnil);
>
>> unwind_data.start = 0;
>
> I confirmed that it makes it work for the corrupted web site in
> question. Thank you!
Here's a proper patch.
[-- Attachment #2: patch --]
[-- Type: text/plain, Size: 4856 bytes --]
From 430ebd936b0bc41bd3e33e171938161846597196 Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Sat, 27 Oct 2018 17:45:52 -0400
Subject: [PATCH v1] Allow partial decompression (Bug#33133)
* src/decompress.c (Fzlib_decompress_region): Add optional
ALLOW-PARTIAL parameter.
* lisp/url/url-http.el (url-handle-content-transfer-encoding): Use it.
* doc/lispref/text.texi (Decompression): Document it.
* etc/NEWS: Announce it.
---
doc/lispref/text.texi | 10 ++++++----
etc/NEWS | 6 ++++++
lisp/url/url-http.el | 5 +++--
src/decompress.c | 22 +++++++++++++++++-----
4 files changed, 32 insertions(+), 11 deletions(-)
diff --git a/doc/lispref/text.texi b/doc/lispref/text.texi
index 6c38d8eed0..e39ba6a192 100644
--- a/doc/lispref/text.texi
+++ b/doc/lispref/text.texi
@@ -4462,14 +4462,16 @@ Decompression
available.
@end defun
-@defun zlib-decompress-region start end
+@defun zlib-decompress-region start end &optional allow-partial
This function decompresses the region between @var{start} and
@var{end}, using built-in zlib decompression. The region should
contain data that were compressed with gzip or zlib. On success, the
function replaces the contents of the region with the decompressed
-data. On failure, the function leaves the region unchanged and
-returns @code{nil}. This function can be called only in unibyte
-buffers.
+data. If @var{allow-partial} is @code{nil}, on failure, the function
+leaves the region unchanged and returns @code{nil}. Otherwise, it
+returns the number of bytes that were not decompressed and replaces
+the region text by whatever data was successfully decompressed. This
+function can be called only in unibyte buffers.
@end defun
diff --git a/etc/NEWS b/etc/NEWS
index 3f86195695..395169253d 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1159,6 +1159,12 @@ to mean that it is not known whether DST is in effect.
'json-insert', 'json-parse-string', and 'json-parse-buffer'. These
are implemented in C using the Jansson library.
++++
+** 'zlib-decompress-region' can partially decompress corrupted data.
+If the new optional ALLOW-PARTIAL argument is passed, then the data
+that was decompressed successfully before failing will be inserted
+into the buffer.
+
** Mailcap
---
diff --git a/lisp/url/url-http.el b/lisp/url/url-http.el
index 6b5749e1bc..94ac660fcf 100644
--- a/lisp/url/url-http.el
+++ b/lisp/url/url-http.el
@@ -939,7 +939,8 @@ url-http-parse-headers
(goto-char (point-min))
success))
-(declare-function zlib-decompress-region "decompress.c" (start end))
+(declare-function zlib-decompress-region "decompress.c"
+ (start end &optional allow-partial))
(defun url-handle-content-transfer-encoding ()
(let ((encoding (mail-fetch-field "content-encoding")))
@@ -951,7 +952,7 @@ url-handle-content-transfer-encoding
(widen)
(goto-char (point-min))
(when (search-forward "\n\n")
- (zlib-decompress-region (point) (point-max)))))))
+ (zlib-decompress-region (point) (point-max) t))))))
;; Miscellaneous
(defun url-http-activate-callback ()
diff --git a/src/decompress.c b/src/decompress.c
index 2836338216..3872014739 100644
--- a/src/decompress.c
+++ b/src/decompress.c
@@ -120,12 +120,18 @@ DEFUN ("zlib-available-p", Fzlib_available_p, Szlib_available_p, 0, 0, 0,
DEFUN ("zlib-decompress-region", Fzlib_decompress_region,
Szlib_decompress_region,
- 2, 2, 0,
+ 2, 3, 0,
doc: /* Decompress a gzip- or zlib-compressed region.
Replace the text in the region by the decompressed data.
-On failure, return nil and leave the data in place.
+
+If optional parameter ALLOW-PARTIAL is nil or omitted, on failure,
+return nil and leave the data in place. Otherwise, return the number
+of bytes that were not decompressed and replace the region text by
+whatever data was successfully decompressed. If decompression is
+completely successful return t.
+
This function can be called only in unibyte buffers. */)
- (Lisp_Object start, Lisp_Object end)
+ (Lisp_Object start, Lisp_Object end, Lisp_Object allow_partial)
{
ptrdiff_t istart, iend, pos_byte;
z_stream stream;
@@ -206,8 +212,14 @@ DEFUN ("zlib-decompress-region", Fzlib_decompress_region,
}
while (inflate_status == Z_OK);
+ Lisp_Object ret = Qt;
if (inflate_status != Z_STREAM_END)
- return unbind_to (count, Qnil);
+ {
+ if (!NILP (allow_partial))
+ ret = make_int (iend - pos_byte);
+ else
+ return unbind_to (count, Qnil);
+ }
unwind_data.start = 0;
@@ -218,7 +230,7 @@ DEFUN ("zlib-decompress-region", Fzlib_decompress_region,
signal_after_change (istart, iend - istart, unwind_data.nbytes);
update_compositions (istart, istart, CHECK_HEAD);
- return unbind_to (count, Qt);
+ return unbind_to (count, ret);
}
\f
--
2.11.0
next prev parent reply other threads:[~2018-10-27 21:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-23 23:07 bug#33133: 26.1.50; zlib-decompress-region too rigid Katsumi Yamaoka
2018-10-24 0:26 ` Noam Postavsky
2018-10-24 1:16 ` Katsumi Yamaoka
2018-10-27 21:48 ` Noam Postavsky [this message]
2018-10-28 15:41 ` Eli Zaretskii
2018-10-31 0:25 ` Noam Postavsky
2018-10-31 16:07 ` Eli Zaretskii
2019-04-03 2:09 ` Noam Postavsky
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