Re: [Lynx-dev] Adding $SOCKS5_PROXY support, changing command line option

[Mouse]

>>> + socks5_proxy =3D (char*)-1;
>> Don=E2=80=99t do that, that is not portable.
> Really??  This i do not understand.

Casting an integer, other than a compile-time constant expression with
value 0, to a pointer?  That is never portable.  (char *)-1 could do
anything from trapping immediately to producing a nil pointer to
producing a pointer that happens to match something else in live use
to, well, pretty much anything.  C99 says (6.3.2.3)

   [#5] An integer  may  be  converted  to  any  pointer  type.
   Exceptaspreviouslyspecified,   the   result   is
   implementation-defined,  might  not  be  correctly  aligned,
   might  not  point  to  an entity of the referenced type, and
   might be a trap representation.56)

The "previously specified" text covers, in [#3], the "integer constant
expression with value 0" case I mentioned above, in which case the
conversion is required to yield a nil pointer (C99 calls this a null
pointer; I don't like that name because of the confusion surrounding
NULL - see http://ftp.rodents-montreal.org/mouse/blah/2009-10-09-1.html
for my thoughts on that).  ([#1], [#2], and [#4] cover conversions
between various pointer types, not relevant to converting integers to
pointers.)

"[I]mplementation-defined" means, among other things, that the next
implementation over may do something completely different from whatever
it is you expect.

Footnote 56 says

   56)The mapping functions for  converting  a  pointer  to  an
  integer  or  an  integer  to a pointer are intended to be
  consistent with the addressing structure of the execution
  environment.

So, in summary, except for the null-pointer-constant special case,
converting integers to pointers is intended to be useful in
machine-dependent code, but is not portable beyond that.

On most current systems, no, it won't cause trouble; it will do pretty
much what you presumably expect.  (While I didn't see enough context to
really know what you expect, most such suggestions come from a mindset
that I can perhaps summarize as "I thought every computer worked the
way mine does", which these days usually means either Windows or Linux
running on x86 or x64.)  In code that's not intended to be portable
beyond "most current systems", it may be fine.  I would hope that lynx
wants to be more portable than that, though.

If you want a distinguished char * pointer that is not nil, the simple
_portable_ thing to do is to allocate a char and point to it:

char magic_value; // maybe static, if not needed beyond file scope

socks5_proxy = _value;
...
if (socks5_proxy == _value) ...

/~\ The ASCII Mouse
\ / Ribbon Campaign
 X  Against HTMLmo...@rodents-montreal.org
/ \ Email!   7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B

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Re: [Lynx-dev] Adding $SOCKS5_PROXY support, changing command line option

[Thorsten Glaser]

Steffen Nurpmeso dixit:

>Really??  This i do not understand.

You’re only allowed to take pointers to actual objects.
It should probably be possible to use NULL somewhere,
but you can use  as magic pointer.

Using (char *)-1 can cause traps on some platforms, or
the compiler to replace the entire codepath (including
backwards!) with nōnsense.

bye,
//mirabilos
-- 
In traditional syntax ' is ignored, but in c99 everything between two ' is
handled as character constant.  Therefore you cannot use ' in a preproces-
sing file in c99 mode.  -- Ragge
No faith left in ISO C99, undefined behaviour, etc.

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Re: [Lynx-dev] Adding $SOCKS5_PROXY support, changing command line option

[Steffen Nurpmeso]

!#!@!!!

Thorsten Glaser wrote in
 :
 |Steffen Nurpmeso dixit:
 |
 ||+ socks5_proxy = (char*)-1;
 |
 |Don’t do that, that is not portable.

Really??  This i do not understand.

 ||   cleanup:
 ||-if (socks5_proxy != NULL) {
 ||+if (socks5_proxy != (char*)-1) {
 ||  FREE(socks5_new_url);
 ||  FREE(socks5_protocol);
 ||  FREE(socks5_host);
 |
 |If this is just for freeing… free(3) takes NULL as no-op.
 |Otherwise, find a better way to flag this.
 |
 |Your patch also changes something wrt. socks5_orig_url.

That is just plain terrible!  What a mess.
Thanks a lot for looking into the patch, Thorsten!

Well, at least this shows i use lynx exclusively via -socks5_proxy
ever since the functionality is there. 
Fixed, and tested with _and_without_ -socks5_proxy. 
(The patch applies to the git snapshot, not the dev5 ball, due to
manual page, the former has the first, the latter the, hmm,
latter.

  -.B \-socks5\-proxy=URL
  -.B \-socks5-proxy=URL

Ciao, and a nice weekend.
Good night.

--steffen
|
|Der Kragenbaer,The moon bear,
|der holt sich munter   he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)
diff --git a/WWW/Library/Implementation/HTTCP.c b/WWW/Library/Implementation/HTTCP.c
index 2834c2c7..49be41f3 100644
--- a/WWW/Library/Implementation/HTTCP.c
+++ b/WWW/Library/Implementation/HTTCP.c
@@ -1847,8 +1847,13 @@ int HTDoConnect(const char *url,
 
 *s = -1;			/* nothing is open yet */
 
-/* In case of a present SOCKS5 proxy, marshal */
-if ((socks5_orig_url = socks5_proxy) != NULL) {
+/* In case of a present SOCKS5 proxy, marshal.
+ * Perform a getenv(3) lookup only once */
+if (socks5_proxy == NULL &&
+	(socks5_proxy = getenv("SOCKS5_PROXY")) == NULL)
+	socks5_proxy = (char*)-1;
+
+if (socks5_proxy != (char*)-1) {
 	int xport;
 
 	xport = default_port;
@@ -2264,7 +2269,7 @@ int HTDoConnect(const char *url,
 #endif /* INET6 */
 
 /* Now if this was a SOCKS5 proxy connection, go for the real one */
-if (status >= 0 && socks5_orig_url != NULL) {
+if (status >= 0 && socks5_proxy != (char*)-1) {
 	unsigned char pbuf[4 + 1 + 255 + 2];
 	unsigned i;
 
@@ -2393,7 +2398,7 @@ int HTDoConnect(const char *url,
 }
 
   cleanup:
-if (socks5_proxy != NULL) {
+if (socks5_proxy != (char*)-1) {
 	FREE(socks5_new_url);
 	FREE(socks5_protocol);
 	FREE(socks5_host);
diff --git a/lynx.man b/lynx.man
index 14927858..4b8ca61a 100644
--- a/lynx.man
+++ b/lynx.man
@@ -805,9 +805,16 @@ If enabled the transfer rate is shown in bytes/second.
 If disabled, no transfer rate is shown.
 Use lynx.cfg or the options menu to select KB/second and/or ETA.
 .TP
-.B \-socks5\-proxy=URL
-(Via which) SOCKS5 proxy to connect.
-This controls the builtin SOCKS5 support, and is therefore unrelated to
+.B \-socks5_proxy=URL
+(Via which) SOCKS5 proxy to connect: any network traffic, including all
+DNS resolutions but the one for URL itself, will be redirected through
+the SOCKS5 proxy.
+URL may be given as \*(``proxy.example.com\*('',
+\*(``proxy.example.com:1080\*('', \*(``192.168.0.1\*('', or
+\*(``192.168.0.1:1080\*('' (and IPv6 notation if so supported).
+A SOCKS5 proxy may also be specified via the environment variable
+.B SOCKS5_PROXY .
+This option controls the builtin SOCKS5 support, which is unrelated to
 the option \fB\-nosocks\fP.
 .TP
 .B \-soft_dquotes
@@ -1138,6 +1145,11 @@ wais_proxy
 .IP
 See \fBLynx Users Guide\fR for additional details and examples.
 .TP
+.B SOCKS5_PROXY
+Is inspected if
+.B \-socks5_proxy
+has not been used (for the same content).
+.TP
 .B SSL_CERT_DIR
 Set to the directory containing trusted certificates.
 .TP
diff --git a/src/LYMain.c b/src/LYMain.c
index 6d5166d4..45fc3ce2 100644
--- a/src/LYMain.c
+++ b/src/LYMain.c
@@ -3916,7 +3916,7 @@ saves session to that file on exit"
),
 #endif
PARSE_STR(
-  "socks5-proxy",	2|NEED_LYSTRING_ARG,	socks5_proxy,
+  "socks5_proxy",	2|NEED_LYSTRING_ARG,	socks5_proxy,
   "=URL\n(via which) SOCKS5 proxy to connect (unrelated to -nosocks!)"
),
PARSE_SET(
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Re: [Lynx-dev] Adding $SOCKS5_PROXY support, changing command line option

[Thorsten Glaser]

Steffen Nurpmeso dixit:

 |+ socks5_proxy = (char*)-1;

Don’t do that, that is not portable.

 |   cleanup:
 |-if (socks5_proxy != NULL) {
 |+if (socks5_proxy != (char*)-1) {
 |  FREE(socks5_new_url);
 |  FREE(socks5_protocol);
 |  FREE(socks5_host);

If this is just for freeing… free(3) takes NULL as no-op.
Otherwise, find a better way to flag this.

Your patch also changes something wrt. socks5_orig_url.

bye,
//mirabilos
-- 
Support mksh as /bin/sh and RoQA dash NOW!
‣ src:bash (389 (415) bugs: 1 RC, 264 (283) I, 124 (131) M, 0 F)
‣ src:dash (90 (105) bugs: 0 RC, 48 (52) I, 42 (53) M, 0 F)
‣ src:mksh (0 bugs: 0 RC, 0 I, 0 M, 0 F)
dash has two RC bugs they just closed because they don’t care about quality…

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Re: [Lynx-dev] Adding $SOCKS5_PROXY support, changing command line option

[Steffen Nurpmeso]

Hello.

In April i sent a message saying

Steffen Nurpmeso wrote in
 <20200421152638.pl92s%stef...@sdaoden.eu>:
 |Please find attached an extension to the -socks5-proxy patch that
 |made it in.  On FreeBSD, they have started adding support for
 |a $SOCKS5_PROXY environment variable, see for example commit
 |[bf579e30a4d54a2d7203cdb1d1689dde46db5db6]:
 |
 |  ...
 |  This change adds SOCKS5 support to the library fetch(3) and
 |  updates the man page.
 |
 |  Details: Within the fetch_connect() function, fetch(3) checks if
 |  the SOCKS5_PROXY environment variable is set. If so, it connects
 |  to this host rather than the end-host. It then initializes the
 |  SOCKS5 connection in
 |  ...
 |
 |I felt it would be nice to integrate within this automatic proxy
 |selection and added support for the MUA i maintain (in as of
 |v14.9.18), and here is the same for lynx.
 |
 |I also changed the option name -socks5-proxy to -socks5_proxy,
 |i apologise for creating an option name that stands out from all
 |other options at first.  Sorry.
 |
 |Better documentation comes as part of this, too.
 |
 |Ciao and good luck everybody from Germany,
 ...

Is there any interest in that?

 |diff --git a/WWW/Library/Implementation/HTTCP.c b/WWW/Library/Implementa\
 |tion/HTTCP.c
 |index 2834c2c7..e3ef663e 100644
 |--- a/WWW/Library/Implementation/HTTCP.c
 |+++ b/WWW/Library/Implementation/HTTCP.c
 |@@ -1847,8 +1847,13 @@ int HTDoConnect(const char *url,
 | 
 | *s = -1; /* nothing is open yet */
 | 
 |-/* In case of a present SOCKS5 proxy, marshal */
 |-if ((socks5_orig_url = socks5_proxy) != NULL) {
 |+/* In case of a present SOCKS5 proxy, marshal.
 |+ * Perform a getenv(3) lookup only once */
 |+if (socks5_proxy == NULL &&
 |+ (socks5_proxy = getenv("SOCKS5_PROXY")) == NULL)
 |+ socks5_proxy = (char*)-1;
 |+
 |+if (socks5_proxy != (char*)-1) {
 |  int xport;
 | 
 |  xport = default_port;
 |@@ -2393,7 +2398,7 @@ int HTDoConnect(const char *url,
 |}
 | 
 |   cleanup:
 |-if (socks5_proxy != NULL) {
 |+if (socks5_proxy != (char*)-1) {
 |  FREE(socks5_new_url);
 |  FREE(socks5_protocol);
 |  FREE(socks5_host);
 |diff --git a/lynx.man b/lynx.man
 |index e1900a28..5b6e011c 100644
 |--- a/lynx.man
 |+++ b/lynx.man
 |@@ -805,9 +805,16 @@ If enabled the transfer rate is shown in bytes/second.
 | If disabled, no transfer rate is shown.
 | Use lynx.cfg or the options menu to select KB/second and/or ETA.
 | .TP
 |-.B \-socks5-proxy=URL
 |-(Via which) SOCKS5 proxy to connect.
 |-This controls the builtin SOCKS5 support, and is therefore unrelated to
 |+.B \-socks5_proxy=URL
 |+(Via which) SOCKS5 proxy to connect: any network traffic, including all
 |+DNS resolutions but the one for URL itself, will be redirected through
 |+the SOCKS5 proxy.
 |+URL may be given as \*(``proxy.example.com\*('',
 |+\*(``proxy.example.com:1080\*('', \*(``192.168.0.1\*('', or
 |+\*(``192.168.0.1:1080\*('' (and IPv6 notation if so supported).
 |+A SOCKS5 proxy may also be specified via the environment variable
 |+.B SOCKS5_PROXY .
 |+This option controls the builtin SOCKS5 support, which is unrelated to
 | the option \fB\-nosocks\fP.
 | .TP
 | .B \-soft_dquotes
 |@@ -1139,6 +1146,11 @@ wais_proxy
 | .IP
 | See \fBLynx Users Guide\fR for additional details and examples.
 | .TP
 |+.B SOCKS5_PROXY
 |+Is inspected if
 |+.B \-socks5_proxy
 |+has not been used (for the same content).
 |+.TP
 | .B SSL_CERT_DIR
 | Set to the directory containing trusted certificates.
 | .TP
 |diff --git a/src/LYMain.c b/src/LYMain.c
 |index 6d5166d4..45fc3ce2 100644
 |--- a/src/LYMain.c
 |+++ b/src/LYMain.c
 |@@ -3916,7 +3916,7 @@ saves session to that file on exit"
 |),
 | #endif
 |PARSE_STR(
 |-  "socks5-proxy",2|NEED_LYSTRING_ARG,socks5_proxy,
 |+  "socks5_proxy",2|NEED_LYSTRING_ARG,socks5_proxy,
 |   "=URL\n(via which) SOCKS5 proxy to connect (unrelated to -nosocks!)"
 |),
 |PARSE_SET(

--steffen
|
|Der Kragenbaer,The moon bear,
|der holt sich munter   he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)

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Re: [Lynx-dev] Any Chance of a "reader mode" in LYNX?

[Thomas Dickey]

- Original Message -
| From: "Chime Hart" 
| To: "lynx-dev" 
| Sent: Friday, August 7, 2020 4:10:33 PM
| Subject: [Lynx-dev] Any Chance of a "reader mode" in LYNX?

| Hi All: Well, now that it seems an `extreme number of sites have their
| printer friendly articles hidden in some sort of javascript, a good friend
| imformed me that Safari has a reader mode which strips all clutter,
| including toolbars. Wondering if something like that would be possible in
| Lynx? And if it were, I would still want to be able to save an article in
| that form. I have no idea which other browsers have these functions?
| Thanks so much in advance
| Chime

Safari gets that for "free" by a rather large JavaScript interpreter.

-- 
Thomas E. Dickey 
http://invisible-island.net
ftp://ftp.invisible-island.net

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[Lynx-dev] Any Chance of a "reader mode" in LYNX?

[Chime Hart]

Hi All: Well, now that it seems an `extreme number of sites have their 
printer friendly articles hidden in some sort of javascript, a good friend 
imformed me that Safari has a reader mode which strips all clutter, 
including toolbars. Wondering if something like that would be possible in 
Lynx? And if it were, I would still want to be able to save an article in 
that form. I have no idea which other browsers have these functions? 
Thanks so much in advance

Chime

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