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lancer6238@yahoo.com
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 Posted: Wed Nov 19, 2008 1:11 am Post subject: Obtain filenames from a directory (Pcap program) |
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Hi all,
I'm writing a program using libpcap, and I have multiple pcap files in
a folder that I want to capture.
I currently have
handle = pcap_open_offline("/data/traffic/pcap1.pcap", errbuf");
which works fine since pcap_open_offline() takes in a filename.
However, I want to process multiple pcap files from the directory /
data/traffic/ at once. Is there a way to do that?
Thank you.
Regards,
Rayne |
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Maxwell Lol
Guest
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| Posted: Wed Nov 19, 2008 7:53 pm Post subject: Re: Obtain filenames from a directory (Pcap program) |
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"lancer6238@yahoo.com" <lancer6238@yahoo.com> writes:
| Quote: | Hi all,
I'm writing a program using libpcap, and I have multiple pcap files in
a folder that I want to capture.
I currently have
handle = pcap_open_offline("/data/traffic/pcap1.pcap", errbuf");
which works fine since pcap_open_offline() takes in a filename.
However, I want to process multiple pcap files from the directory /
data/traffic/ at once. Is there a way to do that?
|
Sure. But it might help if you mention the language you are programming in.
Do you need to read these files simultaneously or. sequentially. Is there a real-time need?
Can you write a program that parses arguments?
Normally people would write a program that reads filenames from the command line, i.e.
myprogram /data/traffic/*.pcap
Is this acceptable? |
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lancer6238@yahoo.com
Guest
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| Posted: Thu Nov 20, 2008 1:08 am Post subject: Re: Obtain filenames from a directory (Pcap program) |
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On Nov 19, 9:53 pm, Maxwell Lol <nos...@com.invalid> wrote:
| Quote: | "lancer6...@yahoo.com" <lancer6...@yahoo.com> writes:
Hi all,
I'm writing a program using libpcap, and I have multiple pcap files in
a folder that I want to capture.
I currently have
handle = pcap_open_offline("/data/traffic/pcap1.pcap", errbuf");
which works fine since pcap_open_offline() takes in a filename.
However, I want to process multiple pcap files from the directory /
data/traffic/ at once. Is there a way to do that?
Sure. But it might help if you mention the language you are programming in.
Do you need to read these files simultaneously or. sequentially. Is there a real-time need?
Can you write a program that parses arguments?
Normally people would write a program that reads filenames from the command line, i.e.
myprogram /data/traffic/*.pcap
Is this acceptable?
|
I'm programming in C. The files can be read squentially. There is no
real-time need.
I can write a program that parses arguments, but I am now using the
function glob which I believe would achieve the same results.
The glob function gives me the filenames of all the files in the
directory, but I still have trouble getting pcap_open_offline to read
from all the pcap files.
I now have
glob_t globbuf;
glob("/data/traffic/*.pcap", GLOB_ERR, NULL, &globbuf);
handle = pcap_open_offline(*(globbuf.gl_pathv), errbuf);
However, pcap_open_offline would only process the first pcap file in
the globbuf.gl_pathv list. How do I get pcap_open_offline to process
all files in the directory? Or do I need to use another function?
If I were to use an array of "handle", one for each pcap file, how do
I make sure pcap_loop will process each handle?
Thank you. |
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lancer6238@yahoo.com
Guest
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| Posted: Thu Nov 20, 2008 1:19 am Post subject: Re: Obtain filenames from a directory (Pcap program) |
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On Nov 20, 9:08 am, "lancer6...@yahoo.com" <lancer6...@yahoo.com>
wrote:
| Quote: | On Nov 19, 9:53 pm, Maxwell Lol <nos...@com.invalid> wrote:
"lancer6...@yahoo.com" <lancer6...@yahoo.com> writes:
Hi all,
I'm writing a program using libpcap, and I have multiple pcap files in
a folder that I want to capture.
I currently have
handle = pcap_open_offline("/data/traffic/pcap1.pcap", errbuf");
which works fine since pcap_open_offline() takes in a filename.
However, I want to process multiple pcap files from the directory /
data/traffic/ at once. Is there a way to do that?
Sure. But it might help if you mention the language you are programming in.
Do you need to read these files simultaneously or. sequentially. Is there a real-time need?
Can you write a program that parses arguments?
Normally people would write a program that reads filenames from the command line, i.e.
myprogram /data/traffic/*.pcap
Is this acceptable?
I'm programming in C. The files can be read squentially. There is no
real-time need.
I can write a program that parses arguments, but I am now using the
function glob which I believe would achieve the same results.
The glob function gives me the filenames of all the files in the
directory, but I still have trouble getting pcap_open_offline to read
from all the pcap files.
I now have
glob_t globbuf;
glob("/data/traffic/*.pcap", GLOB_ERR, NULL, &globbuf);
handle = pcap_open_offline(*(globbuf.gl_pathv), errbuf);
However, pcap_open_offline would only process the first pcap file in
the globbuf.gl_pathv list. How do I get pcap_open_offline to process
all files in the directory? Or do I need to use another function?
If I were to use an array of "handle", one for each pcap file, how do
I make sure pcap_loop will process each handle?
Thank you.
|
I just figured out that I just have to loop pcap_loop as many times as
the number of files/handle I have to process each file.
Thank you for your help! |
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Lew Pitcher
Guest
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| Posted: Thu Nov 20, 2008 7:38 am Post subject: Re: Obtain filenames from a directory (Pcap program) |
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On November 19, 2008 20:08, in comp.os.linux.networking,
lancer6238@yahoo.com (lancer6238@yahoo.com) wrote:
| Quote: | On Nov 19, 9:53 pm, Maxwell Lol <nos...@com.invalid> wrote:
"lancer6...@yahoo.com" <lancer6...@yahoo.com> writes:
Hi all,
I'm writing a program using libpcap, and I have multiple pcap files in
a folder that I want to capture.
I currently have
handle = pcap_open_offline("/data/traffic/pcap1.pcap", errbuf");
which works fine since pcap_open_offline() takes in a filename.
However, I want to process multiple pcap files from the directory /
data/traffic/ at once. Is there a way to do that?
Sure. But it might help if you mention the language you are programming
in. Do you need to read these files simultaneously or. sequentially. Is
there a real-time need?
Can you write a program that parses arguments?
Normally people would write a program that reads filenames from the
command line, i.e.
myprogram /data/traffic/*.pcap
Is this acceptable?
I'm programming in C. The files can be read squentially. There is no
real-time need.
I can write a program that parses arguments, but I am now using the
function glob which I believe would achieve the same results.
|
Hmmmm.... To each his own.
I'd find it easier to loop through multiple argv[] entries than I would to
(a) force the end user to single-quote the pathname so that the program
could run its own glob() call, and (b) loop through all the results of the
glob() call. But, you may be different.
| Quote: | The glob function gives me the filenames of all the files in the
directory, but I still have trouble getting pcap_open_offline to read
from all the pcap files.
I now have
glob_t globbuf;
glob("/data/traffic/*.pcap", GLOB_ERR, NULL, &globbuf);
handle = pcap_open_offline(*(globbuf.gl_pathv), errbuf);
|
glob() returns a list of matching paths in gl_pathv, and a count of the
number of matching paths in gl_pathc (see the glob(3) manpage)
So, your code would really be...
glob_t globbuf;
if (glob("/data/traffic/*.pcap", GLOB_ERR, NULL, &globbuf) == 0)
{ /* glob() didnt encounter any errors */
/* loop through all the matched paths */
while (globbuf.gl_pathc-- > 0)
{ /* process one matched path */
/* use the path, advance to the next in the list */
handle = pcap_open_offline(*(globbuf.gl_pathv++), errbuf);
/* rest of the pcap_ processing goes here */
}
globfree(&globbuf);
}
| Quote: | However, pcap_open_offline would only process the first pcap file in
the globbuf.gl_pathv list.
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Of course. pcap_open_offline knows nothing of the glob() list. It expects
only one path, not a list of paths.
| Quote: | How do I get pcap_open_offline to process all files in the directory?
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See my example above
| Quote: | Or do I need to use another function?
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Not really. Just use what glob() gives you.
You really want to read (and understand) glob(3) ("man 3 glob")
| Quote: | If I were to use an array of "handle", one for each pcap file, how do
I make sure pcap_loop will process each handle?
|
From the looks of the documentation (see pcap(3)), pcap_loop() loops through
the data in one (and only one) pcap_t * (that which you call 'handle'). You
make sure that pcap_loop() processes each handle by having pcap_loop()
process each handle. That is to say, all in all, your glob/pcap logic
should look something like
glob_t globbuf;
if (glob("/data/traffic/*.pcap", GLOB_ERR, NULL, &globbuf) == 0)
{ /* glob() didnt encounter any errors */
/* loop through all the matched paths */
while (globbuf.gl_pathc-- > 0)
{ /* process one matched path */
/* use the path, advance to the next in the list */
handle = pcap_open_offline(*(globbuf.gl_pathv++), errbuf);
while (pcap_loop(handle,...) > 0)
{
/* all the work is done by pcap_loop() */
/* so this can be a dummy statement */
}
pcap_close(handle);
}
globfree(&globbuf);
}
(Bear in mind that I've not written any pcap* code before, and am going just
by the manpage. The actual logic will probably be a lot more complex than
that)
HTH
--
Lew Pitcher
Master Codewright & JOAT-in-training | Registered Linux User #112576
http://pitcher.digitalfreehold.ca/ | GPG public key available by request
---------- Slackware - Because I know what I'm doing. ------ |
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Chris Davies
Guest
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| Posted: Fri Nov 21, 2008 6:08 pm Post subject: Re: Obtain filenames from a directory (Pcap program) |
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lancer6238@yahoo.com <lancer6238@yahoo.com> wrote:
| Quote: | I can write a program that parses arguments, but I am now using the
function glob which I believe would achieve the same results.
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You're thinking too much like DOS. Your program doesn't need to expand
the list of arguments - the shell will do that for you:
your_program *.whatever
This will give you all the files ending with ".whatever" and you can
iterate across main()'s argv[].
Chris |
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