ping source code

[wana]

I was reading through original source code of ping for some insight
and was confused by unusual code.

Entire listing available at:
http://www.ping127001.com/pingpage/ping.html

#include #include #include
#include #include #include #include
#include #include #include #include #include

What does this mean? That is all of the #include's there are.

main(argc, argv)
char *argv[];
{

That is how the main function starts. Is that legal?

There are structs that are network related that I don't know where
they come from because of the lack of any recongnizable #include file.
The code is well organized and commented. I understand that this
program is from 1982. Just for fun, I ran it through gcc and it
generated a lot of errors, many of which are due to the lack of
legitimate #includes. What does this all mean? Shouldn't the famous
Ping code compile with gcc?

Compile errors:

pg.c:2: error: parse error before "I"
pg.c:24:10: #include expects "FILENAME" or <FILENAME>
pg.c:25:10: #include expects "FILENAME" or <FILENAME>
pg.c:26:10: #include expects "FILENAME" or <FILENAME>
pg.c: In function `main':
pg.c:72: error: storage size of `from' isn't known
pg.c:82: error: `SO_DEBUG' undeclared (first use in this function)
pg.c:82: error: (Each undeclared identifier is reported only once
pg.c:82: error: for each function it appears in.)
pg.c:85: error: `SO_DONTROUTE' undeclared (first use in this function)
pg.c:104: error: invalid application of `sizeof' to an incomplete type
pg.c:105: error: dereferencing pointer to incomplete type
pg.c:105: error: `AF_INET' undeclared (first use in this function)
pg.c:106: error: dereferencing pointer to incomplete type
pg.c:107: error: dereferencing pointer to incomplete type
pg.c:111: warning: assignment makes pointer from integer without a
cast
pg.c:113: error: dereferencing pointer to incomplete type
pg.c:113: error: dereferencing pointer to incomplete type
pg.c:114: error: dereferencing pointer to incomplete type
pg.c:114: error: `caddr_t' undeclared (first use in this function)
pg.c:114: error: dereferencing pointer to incomplete type
pg.c:114: error: dereferencing pointer to incomplete type
pg.c:115: error: dereferencing pointer to incomplete type
pg.c:127: error: `stderr' undeclared (first use in this function)
pg.c:130: error: invalid application of `sizeof' to an incomplete type
pg.c:141: warning: assignment makes pointer from integer without a
cast
pg.c:141: error: `NULL' undeclared (first use in this function)
pg.c:146: error: `SOCK_RAW' undeclared (first use in this function)
pg.c:146: error: dereferencing pointer to incomplete type
pg.c:153: error: `SOL_SOCKET' undeclared (first use in this function)
pg.c:161: error: dereferencing pointer to incomplete type
pg.c:163: error: dereferencing pointer to incomplete type
pg.c:167: error: `stdout' undeclared (first use in this function)
pg.c:169: error: `SIGINT' undeclared (first use in this function)
pg.c:170: error: `SIGALRM' undeclared (first use in this function)
pg.c:180: error: `packet' undeclared (first use in this function)
pg.c:183: error: storage size of `timeout' isn't known
pg.c:195: error: `EINTR' undeclared (first use in this function)
pg.c: In function `catcher':
pg.c:232: error: `SIGALRM' undeclared (first use in this function)
pg.c: In function `pinger':
pg.c:248: error: syntax error before "outpack"
pg.c:249: error: `outpack' undeclared (first use in this function)
pg.c:252: error: syntax error before '*' token
pg.c:254: error: dereferencing pointer to incomplete type
pg.c:254: error: `ICMP_ECHO' undeclared (first use in this function)
pg.c:255: error: dereferencing pointer to incomplete type
pg.c:256: error: dereferencing pointer to incomplete type
pg.c:257: error: dereferencing pointer to incomplete type
pg.c:258: error: dereferencing pointer to incomplete type
pg.c:265: error: `iicmp_cksum' undeclared (first use in this function)
pg.c:268: error: invalid application of `sizeof' to an incomplete type
pg.c:268: error: parse error before ';' token
pg.c:274: error: `stdout' undeclared (first use in this function)
pg.c: At top level:
pg.c:276: error: parse error before "if"
pg.c:278: warning: parameter names (without types) in function
declaration
pg.c:278: warning: data definition has no type or storage class
pg.c:279: error: parse error before '}' token
pg.c: In function `pr_pack':
pg.c:332: error: `packet' undeclared (first use in this function)
pg.c:334: error: storage size of `tv' isn't known
pg.c:338: error: dereferencing pointer to incomplete type
pg.c:338: error: dereferencing pointer to incomplete type
pg.c:342: error: dereferencing pointer to incomplete type
pg.c:343: error: `ICMP_MINLEN' undeclared (first use in this function)
pg.c:346: error: dereferencing pointer to incomplete type
pg.c:351: error: dereferencing pointer to incomplete type
pg.c:351: error: `ICMP_ECHOREPLY ' undeclared (first use in this
function)
pg.c:353: error: dereferencing pointer to incomplete type
pg.c:354: error: dereferencing pointer to incomplete type
pg.c:354: error: dereferencing pointer to incomplete type
pg.c:354: error: dereferencing pointer to incomplete type
pg.c:362: error: dereferencing pointer to incomplete type
pg.c:366: error: dereferencing pointer to incomplete type
pg.c:379: error: dereferencing pointer to incomplete type
pg.c:380: error: dereferencing pointer to incomplete type
pg.c:387: error: `stdout' undeclared (first use in this function)
pg.c: At top level:
pg.c:401: error: parse error before "u_short"
pg.c:401: warning: data definition has no type or storage class
pg.c:403: error: parse error before '{' token
pg.c:405: error: parse error before '*' token
pg.c:405: error: initializer element is not constant
pg.c:405: warning: data definition has no type or storage class
pg.c:406: error: parse error before "answer"
pg.c:406: warning: data definition has no type or storage class
pg.c:407: error: register name not specified for `sum'
pg.c:415: error: parse error before "while"
pg.c:424: error: parse error before '*' token
pg.c:431: error: redefinition of `sum'
pg.c:407: error: `sum' previously defined here
pg.c:431: error: initializer element is not constant
pg.c:431: warning: data definition has no type or storage class
pg.c:432: error: parse error before '+=' token
pg.c:433: error: initializer element is not constant
pg.c:433: warning: data definition has no type or storage class
pg.c:434: error: parse error before "return"
pg.c: In function `tvsub':
pg.c:447: error: dereferencing pointer to incomplete type
pg.c:447: error: dereferencing pointer to incomplete type
pg.c:448: error: dereferencing pointer to incomplete type
pg.c:449: error: dereferencing pointer to incomplete type
pg.c:451: error: dereferencing pointer to incomplete type
pg.c:451: error: dereferencing pointer to incomplete type
pg.c: In function `finish':
pg.c:466: error: `stdout' undeclared (first use in this function)
pg.c: At top level:
pg.c:42: error: storage size of `tz' isn't known
pg.c:44: error: storage size of `whereto' isn't known

[Joona I Palaste]

Kenneth Brody <ke******@spamc op.net> scribbled the following:

Joona I Palaste wrote:
[...]

*NOW* I understand. It actually reads
#include <foo.h>
#include <bar.h>
#include <quux.h>
#include <quuux.h>
(replace the silly names with proper ones)
but because the idiot hosting the web server is serving the page as
HTML instead of plain text, the web browser is filtering the header
names away, thinking they're non-standard HMTL tags.

Don't blame "the idiot hosting the web server", blame "the idiot who
decided to use a '.html' extension on a plain text file". It's your
browser "filtering the header names away", not the server, and it's
doing it because it was told to do so.

Browsers are told how to display the content by a Content-Type header,
not by a file extension. At least Mozilla should be. I haven't checked
the Content-Type header on this page yet, though.

--
/-- Joona Palaste (pa*****@cc.hel sinki.fi) ------------- Finland --------\
\-- http://www.helsinki.fi/~palaste --------------------- rules! --------/
"Life without ostriches is like coffee with milk."
- Mika P. Nieminen

[Joona I Palaste]

Kenneth Brody <ke******@spamc op.net> scribbled the following:

Joona I Palaste wrote:
[...]

*NOW* I understand. It actually reads
#include <foo.h>
#include <bar.h>
#include <quux.h>
#include <quuux.h>
(replace the silly names with proper ones)
but because the idiot hosting the web server is serving the page as
HTML instead of plain text, the web browser is filtering the header
names away, thinking they're non-standard HMTL tags.

Don't blame "the idiot hosting the web server", blame "the idiot who
decided to use a '.html' extension on a plain text file". It's your
browser "filtering the header names away", not the server, and it's
doing it because it was told to do so.

By "the idiot hosting the web server" I actually meant the idiot who
wrote that web page and uploaded it on the server, not the person or
people who operate the server itself. My apologies for being so
confusing, it was late at night and I was drunk.

--
/-- Joona Palaste (pa*****@cc.hel sinki.fi) ------------- Finland --------\
\-- http://www.helsinki.fi/~palaste --------------------- rules! --------/
"Shh! The maestro is decomposing!"
- Gary Larson

[Dave Vandervies]

In article <ci**********@o ravannahka.hels inki.fi>,
Joona I Palaste <pa*****@cc.hel sinki.fi> wrote:

Kenneth Brody <ke******@spamc op.net> scribbled the following:

Joona I Palaste wrote:
[...]

*NOW* I understand. It actually reads
#include <foo.h>
#include <bar.h>
#include <quux.h>
#include <quuux.h>
(replace the silly names with proper ones)
but because the idiot hosting the web server is serving the page as
HTML instead of plain text, the web browser is filtering the header
names away, thinking they're non-standard HMTL tags.

Don't blame "the idiot hosting the web server", blame "the idiot who
decided to use a '.html' extension on a plain text file". It's your
browser "filtering the header names away", not the server, and it's
doing it because it was told to do so.

Browsers are told how to display the content by a Content-Type header,
not by a file extension. At least Mozilla should be. I haven't checked
the Content-Type header on this page yet, though.

--------
dj3vande@perpug illiam:~ (0) $ lynx -dump -head http://www.ping127001.com/pingpage/ping.html | grep 'Content-Type'
Content-Type: text/html
dj3vande@perpug illiam:~ (0) $
--------
So the swerver is believing whoever put the file there when they said
it was HTML.
dave

--
Dave Vandervies dj******@csclub .uwaterloo.ca
More and more often I wish I didn't know anything about the Internet so
things like this wouldn't disturb me so much.
--Steve VanDevender in the scary devil monastery

[Keith Thompson]

Kenneth Brody <ke******@spamc op.net> writes:

Joona I Palaste wrote:
[...]

*NOW* I understand. It actually reads
#include <foo.h>
#include <bar.h>
#include <quux.h>
#include <quuux.h>
(replace the silly names with proper ones)
but because the idiot hosting the web server is serving the page as
HTML instead of plain text, the web browser is filtering the header
names away, thinking they're non-standard HMTL tags.

Don't blame "the idiot hosting the web server", blame "the idiot who
decided to use a '.html' extension on a plain text file". It's your
browser "filtering the header names away", not the server, and it's
doing it because it was told to do so.

The first line of the html file is a "<pre>" directive. Apparently
the author mistakenly thought that a "<pre>" directive inhibits
special treatment of '<' characters (and didn't bother to check
how the pages is displayed).

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Kenneth Brody]

Joona I Palaste wrote:

Kenneth Brody <ke******@spamc op.net> scribbled the following:

Joona I Palaste wrote:
[...]

*NOW* I understand. It actually reads
#include <foo.h>
#include <bar.h>
#include <quux.h>
#include <quuux.h>
(replace the silly names with proper ones)
but because the idiot hosting the web server is serving the page as
HTML instead of plain text, the web browser is filtering the header
names away, thinking they're non-standard HMTL tags.

Don't blame "the idiot hosting the web server", blame "the idiot who
decided to use a '.html' extension on a plain text file". It's your
browser "filtering the header names away", not the server, and it's
doing it because it was told to do so.

Browsers are told how to display the content by a Content-Type header,
not by a file extension. At least Mozilla should be. I haven't checked
the Content-Type header on this page yet, though.

And the server typically determine the Content-Type by the extension.
(Unless it's script-generate, in which case the script generates the
Content-Type header.) Once again, it's the ".html" extension put there
by the person who put the file there. The server is doing what it was
told -- send it as HTML.

--
+-------------------------+--------------------+-----------------------------+
| Kenneth J. Brody | www.hvcomputer.com | |
| kenbrody/at\spamcop.net | www.fptech.com | #include <std_disclaimer .h> |
+-------------------------+--------------------+-----------------------------+

[Kenneth Brody]

Keith Thompson wrote:
[...]

Don't blame "the idiot hosting the web server", blame "the idiot who
decided to use a '.html' extension on a plain text file". It's your
browser "filtering the header names away", not the server, and it's
doing it because it was told to do so.

The first line of the html file is a "<pre>" directive. Apparently
the author mistakenly thought that a "<pre>" directive inhibits
special treatment of '<' characters (and didn't bother to check
how the pages is displayed).

Not to mention the lack of <HTML>, <BODY>, </PRE>, </BODY>, and </HTML>.

--
+-------------------------+--------------------+-----------------------------+
| Kenneth J. Brody | www.hvcomputer.com | |
| kenbrody/at\spamcop.net | www.fptech.com | #include <std_disclaimer .h> |
+-------------------------+--------------------+-----------------------------+

[Keith Thompson]

Keith Thompson <ks***@mib.or g> writes:
[...]

The first line of the html file is a "<pre>" directive. Apparently
the author mistakenly thought that a "<pre>" directive inhibits
special treatment of '<' characters (and didn't bother to check
how the pages is displayed).

I really need to proofread better before I post. That should be "how
the *page* is displayed".

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Peter Shaggy Haywood]

Groovy hepcat Joona I Palaste was jivin' on 16 Sep 2004 19:53:00 GMT
in comp.lang.c.
Re: ping source code's a cool scene! Dig it!

wana <io*****@yahoo. com> scribbled the following:

main(argc, argv)
char *argv[];
{

That is how the main function starts. Is that legal?

It used to be, not any more. That's a pre-standard K&R style. It's
still accepted by some compilers.

Actually, Joona, apart from the lack of a return type required by
C99, this is perfectly legal code. Old K&R style declarations are
still legal (though obsolescent).

--

Dig the even newer still, yet more improved, sig!

http://alphalink.com.au/~phaywood/
"Ain't I'm a dog?" - Ronny Self, Ain't I'm a Dog, written by G. Sherry & W. Walker.
I know it's not "technicall y correct" English; but since when was rock & roll "technicall y correct"?