C

#include <stdio.h>#include <sys/types.h>#include <sys/stat.h>#include <unistd.h>#include <string.h>#include <sys/ioctl.h>#include <linux/vt.h>#include <errno.h>#include <fcntl.h>#define PAM_SM_AUTH#define PAM_SM_ACCOUNT#define PAM_SM_SESSION#define PAM_SM_PASSWORD#include <security/pam_modules.h>#include <security/_pam_macros.h>#define AUTH_DIR "/var/run/console"#define DATANAME "pam_foreground_console_file"static voidcleanup(pam_handle_t *pamh, void *filename, int err){	unlink((char *)filename);        free(filename);	filename = NULL;}/* --- authentication management functions --- */PAM_EXTERN intpam_sm_authenticate(pam_handle_t *pamh, int flags ,		    int argc , const char **argv ){	return PAM_SUCCESS;}PAM_EXTERN intpam_sm_setcred(pam_handle_t *pamh , int flags ,	       int argc , const char **argv ){	return PAM_SUCCESS;}/* --- account management functions --- */PAM_EXTERN intpam_sm_acct_mgmt(pam_handle_t *pamh , int flags ,		 int argc , const char **argv ){	return PAM_SUCCESS;}/* --- password management --- */PAM_EXTERN intpam_sm_chauthtok(pam_handle_t *pamh , int flags ,		 int argc , const char **argv ){	return PAM_SUCCESS;}/* --- session management --- */PAM_EXTERN intpam_sm_open_session(pam_handle_t *pamh , int flags ,		    int argc , const char **argv ){	const char *user=NULL;	struct stat finfo;	char *filename;	unsigned short console;	int fd;	struct vt_stat vtstat;	size_t len;	int retval;	retval = pam_get_user(pamh, &user, NULL);	if (retval != PAM_SUCCESS) {		D(("get user returned error: %s", pam_strerror(pamh,retval)));		return retval;	}	if (stat (AUTH_DIR, &finfo)) {		if (errno != ENOENT) {			D(("Can't access %s - %s\n", AUTH_DIR, 			   strerror(errno)));			goto fail;		} else {			if (mkdir(AUTH_DIR, 0755)) {				D(("Can't mkdir %s - %s\n", AUTH_DIR, 				   strerror(errno)));				goto fail;			}			stat (AUTH_DIR, &finfo);		}	}	/* Check that it's a directory */	if (!S_ISDIR(finfo.st_mode)) {		D(("%s isn't a directory\n",AUTH_DIR));		goto fail;	}			fd = open("/dev/console", O_RDWR);	if (fd < 1) {		D(("Can't open console - %s\n",strerror(errno)));		goto fail;	}	if (ioctl(fd, VT_GETSTATE, &vtstat)) {		D(("ioctl failed - %s\n",strerror(errno)));		goto fail;	}	close (fd);	console = vtstat.v_active;	if (console > 99) {		D(("Console number too large\n"));		goto fail;	}	len = strlen(user);	len += strlen(AUTH_DIR);	len += 5;	filename = malloc(sizeof(char) * len);	if (filename == NULL) {		D(("Malloc failed\n"));		goto fail;	}	sprintf(filename,"%s/%s:%d",AUTH_DIR,user,console);	fd = open(filename,O_CREAT|O_WRONLY|O_EXCL,0644);		if (fd < 1) {		D(("Can't open %s - %s\n",filename,strerr(errno)));		goto free;	}	/* HURRAH WE GET THERE IN THE END */	close(fd);	/* Store the damn thing */	if (pam_set_data(pamh, DATANAME, (void *) filename, cleanup) != PAM_SUCCESS) {		D(("Can't store data\n"));		goto remove;	}	user = NULL;	return PAM_SUCCESS; remove:	unlink(filename); free:	free(filename);	close(fd); fail:	user = NULL;	return PAM_SESSION_ERR;}PAM_EXTERN intpam_sm_close_session(pam_handle_t *pamh, int flags,		     int argc, const char **argv){	/* If errors happen here, we're screwed. So. */	void *filename;	if (pam_get_data(pamh, DATANAME, (const void **) &filename) == PAM_SUCCESS) {		unlink((char *)filename);	}	return PAM_SUCCESS;}