#include <afs/param.h>
#include <stdio.h>
#include <security/pam_appl.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>


static int my_conv(int num_msg, struct pam_message **msg,
		   struct pam_response **response, void *appdata_ptr);


static struct pam_conv pam_conv = { &my_conv, NULL };


static pam_handle_t *pamh;


static const char *service = "afstest";
static const char *new_envstring = "GOTHEREVIATESTPAM=1";
static const char *new_homestring = "HOME=/tmp";

#ifdef AFS_LINUX20_ENV
#define getpassphrase getpass
#endif


void main(int argc, char *argv[])
{
    int authenticated = 0;
    int retcode;
    char *username;

    if (argc < 2 || argc > 3) {
	fprintf(stderr, "Usage: %s [-u] <user>\n", argv[0]);
	exit(1);
    }
    if (argc == 3) {
	if (strcmp(argv[1], "-u") != 0) {
	    fprintf(stderr, "Usage: %s [-u] <user>\n", argv[0]);
	    exit(1);
	}
	service = "unixtest";
	username = argv[2];
    } else {
	username = argv[1];
    }

    if ((retcode = pam_start(service, username,
			     &pam_conv, &pamh)) != PAM_SUCCESS) {
	fprintf(stderr, "PAM error %d\n", retcode);
	exit(1);
    }

    authenticated = ((retcode = pam_authenticate(pamh, 0)) == PAM_SUCCESS);

    if (!authenticated) {
	fprintf(stderr, "PAM couldn't authenticate you.\n");
	pam_end(pamh, PAM_ABORT);
	exit(1);
    }

    if ((retcode = pam_acct_mgmt(pamh, 0)) != PAM_SUCCESS) {
	fprintf(stderr, "pam_acct_mgmt returned %d.\n", retcode);
	pam_end(pamh, PAM_ABORT);
	exit(1);
    }

    /* pam_open_session */

    if ((retcode = pam_setcred(pamh, PAM_ESTABLISH_CRED)) != PAM_SUCCESS) {
	fprintf(stderr, "pam_setcred returned %d.\n", retcode);
	pam_end(pamh, PAM_ABORT);
	exit(1);
    }

    pam_end(pamh, PAM_SUCCESS);

    putenv(new_envstring);
    putenv(new_homestring);
    chdir("/tmp");
    printf("Type exit to back out.\n");
    execl("/bin/csh", "/bin/csh", NULL);
}


static int my_conv(int num_msg, struct pam_message **msg,
		   struct pam_response **response, void *appdata_ptr)
{
    struct pam_message *m;
    struct pam_response *r;
    char *p;

    m = *msg;
    if (response) {
	*response = calloc(num_msg, sizeof(struct pam_response));
	if (*response == NULL) return PAM_BUF_ERR;
	r = *response;
    } else {
	r = NULL;
    }

    while (num_msg--) {
	switch(m->msg_style) {
	case PAM_PROMPT_ECHO_OFF:
#ifdef __hpux
	    /* ON HP's we still read 8 chars */
	    if (r) r->resp = strdup(getpass(m->msg));
#else
	    if (r) r->resp = strdup(getpassphrase(m->msg));
#endif
	    break;
	case PAM_PROMPT_ECHO_ON:
	    fputs(m->msg, stdout);
	    if (r) {
		r->resp = malloc(PAM_MAX_RESP_SIZE);
		fgets(r->resp, PAM_MAX_RESP_SIZE, stdin);
		r->resp[PAM_MAX_RESP_SIZE-1] = '\0';
		p = &r->resp[strlen(r->resp)-1];
		while (*p == '\n' && p >= r->resp) *(p--) = '\0';
	    }
	    break;
	case PAM_ERROR_MSG:
	    fputs(m->msg, stderr);
	    break;
	case PAM_TEXT_INFO:
	    fputs(m->msg, stdout);
	    break;
	default:
	    break;
	}
	m++;
	if (r) r++;
    }
    return PAM_SUCCESS;
}