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Full Discussion: Get the file descriptor of a socket file. C vs Python.
Top Forums Programming Get the file descriptor of a socket file. C vs Python. Post 302204431 by goon12 on Wednesday 11th of June 2008 03:02:40 PM
Old 06-11-2008
Get the file descriptor of a socket file. C vs Python.
Hi,

I want to validate that a file is a socket file on Linux. I know I can do this using the S_ISSOCK macro, but I am not sure how to get the file descriptor for the socket file.

For example, I know that /tmp/mapping-foo is a socket file. In Python I can do something like this:
Code:
>>> import os
>>> import stat
>>> sb = os.stat('/tmp/mapping-foo')
>>> print stat.S_ISSOCK(sb.st_mode)
True
>>>

How ever in C, I am unable to get the file descriptor for the file /tmp/mapping-foo. I tried using open, fopen and fileno as follows:
Code:
        file_des = open("/tmp/mapping-foo", O_RDONLY);
        if( file_des == -1 ) {
                perror("open(2)");
                if((file = fopen("/tmp/mapping-foo", "r")) == NULL ) {
                        perror("fopen()");
                } else {
                        file_des = fileno(file);
                        if (file_des == -1 ) {
                                perror("fileno()");
                        }
                }
                if( file_des == -1 )
                        exit(1);
        }

But, I am getting this error message:
Code:
$ ls -l /tmp/mapping-foo
srwxrwxr-x 1 joe joe 0 Jun  9 09:53 /tmp/mapping-foo
$ file /tmp/mapping-foo
/tmp/mapping-foo: socket
$ ./pc /tmp/mapping-foo
Stat file /tmp/mapping-foo
open(2): No such device or address
fopen(): No such device or address


I am trying to load the correct file.

Thanks,
Joe
 

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LEARN ABOUT CENTOS

ipa-rmkeytab

ipa-rmkeytab(1) 						 IPA Manual Pages						   ipa-rmkeytab(1)

NAME

       ipa-rmkeytab - Remove a kerberos principal from a keytab

SYNOPSIS

       ipa-rmkeytab [ -p principal-name ] [ -k keytab-file ] [ -r realm ] [ -d ]

DESCRIPTION

       Removes a kerberos principal from a keytab.

       Kerberos  keytabs  are  used  for  services (like sshd) to perform kerberos authentication. A keytab is a file with one or more secrets (or
       keys) for a kerberos principal.

       A kerberos service principal is a kerberos identity that can be used for authentication. Service principals contain the name  of  the  ser-
       vice, the hostname of the server, and the realm name.

       ipa-rmkeytab  provides  two  ways  to  remove  principals.   A specific principal can be removed or all principals for a given realm can be
       removed.

       All encryption types and versions of a principal are removed.

       The realm may be included when removing a specific principal but it is not required.

       NOTE: removing a principal from the keytab does not affect the Kerberos principal stored in the IPA server. It  merely  removes	the  entry
       from the local keytab.

OPTIONS

       -p principal-name
	      The non-realm part of the full principal name.

       -k keytab-file
	      The keytab file to append the principal(s) from.

       -r realm
	      A realm to remove all principals for.

       -d     Debug mode. Additional information is displayed.

EXAMPLES

       Remove the NFS service principal on the host foo.example.com from /tmp/nfs.keytab.

	  # ipa-rmkeytab -p nfs/foo.example.com -k /tmp/nfs.keytab

       Remove the ldap service principal on the host foo.example.com from /etc/krb5.keytab.

	  # ipa-rmkeytab -p ldap/foo.example.com -k /etc/krb5.keytab

       Remove all principals for the realm EXAMPLE.COM.

	 # ipa-rmkeytab -r EXAMPLE.COM -k /etc/krb5.keytab

EXIT STATUS

       The exit status is 0 on success, nonzero on error.

       1 Kerberos initialization failed

       2 Memory allocation error

       3 Unable to open keytab

       4 Unable to parse the principal name

       5 Principal name or realm not found in keytab

       6 Unable to remove principal from keytab

IPA
								    Oct 30 2009 						   ipa-rmkeytab(1)
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