module writing / compiling problems?

Jason Gerfen jason.gerfen at scl.utah.edu
Wed Jun 9 22:34:28 UTC 2004


I am doing something wrong as it comes to writting a pam module.  If 
anyone can tell me what I am doing wrong, it would be greatly appreciated.

This module does one thing, on the pam_sm_authenticate() function it 
attempts to call the pam_get_user() function and on success or failure 
it logs it to syslog using a _pam_log() function.

Here is the code:  File is named lame.c
[SNIP]
#include <stdio.h>
#include <syslog.h>
#include <stdarg.h>

#define PAM_SM_AUTH

#include <pam_modules.h>

static void _pam_log(int err, const char *format, ...)
{
    va_list  args;

    va_start(args, format);
    openlog("PAM-lame", LOG_CONS | LOG_PID, LOG_AUTHPRIV);
    syslog(err, format, args);
    va_end(args);
    closelog();
}

PAM_EXTERN
int pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc,
            const char **argv)
{
    int retval;
    const char *user;

    if((retval = pam_get_user(pamh, &user, "looser login:") != 
PAM_SUCCESS)) {
    _pam_log(LOG_ERR, "Cannot obtain user name: %s",
         pam_strerror(pamh, retval));
    return(PAM_AUTHINFO_UNAVAIL); }

    if((retval = pam_get_user(pamh, &user, "looser login:") == 
PAM_SUCCESS)) {
        _pam_log(LOG_ERR, "Obtained username: %s",
         pam_strerror(pamh, retval));
        return(PAM_SUCCESS); }

    _pam_log(LOG_ERR, "Just checking", pam_strerror(pamh, retval));

    return retval;

}

#ifdef PAM_STATIC
struct pam_module _pam_looser_modstruct = {
    "pam_looser",
    pam_sm_authenticate,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
};
#endif
[/SNIP]

And I am compiling using a simply Makefile listed below:
[SNIP]
#include <stdio.h>
#include <syslog.h>
#include <stdarg.h>

#define PAM_SM_AUTH

#include <pam_modules.h>

static void _pam_log(int err, const char *format, ...)
{
    va_list  args;

    va_start(args, format);
    openlog("PAM-lame", LOG_CONS | LOG_PID, LOG_AUTHPRIV);
    syslog(err, format, args);
    va_end(args);
    closelog();
}

PAM_EXTERN
int pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc,
            const char **argv)
{
    int retval;
    const char *user;

    if((retval = pam_get_user(pamh, &user, "looser login:") != 
PAM_SUCCESS)) {
    _pam_log(LOG_ERR, "Cannot obtain user name: %s",
         pam_strerror(pamh, retval));
    return(PAM_AUTHINFO_UNAVAIL); }

    if((retval = pam_get_user(pamh, &user, "looser login:") == 
PAM_SUCCESS)) {
        _pam_log(LOG_ERR, "Obtained username: %s",
         pam_strerror(pamh, retval));
        return(PAM_SUCCESS); }

    _pam_log(LOG_ERR, "Just checking", pam_strerror(pamh, retval));

    return retval;

}

#ifdef PAM_STATIC
struct pam_module _pam_looser_modstruct = {
    "pam_looser",
    pam_sm_authenticate,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
};
#endif
[/SNIP]

Any help tips, pointers etc would be greatly appreciated.  Also if there is a "typo" please disregard as on the production box it compiles just fine, and of couse I do have it added to the /etc/pam.d/login file like so:

auth required pam_looser.so

Thanks in advance,

-- 
Jason Gerfen

"...Sometimes I just yell at myself. And it
 makes me sad, sometimes I make myself cry..."
			~ My nephew Dawsyn






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