source: trunk/debathena/debathena/libpam-debathena-home-type/pam_debathena_home_type.c @ 22686

/*
 * pam_debathena_home_type.c
 * PAM session management functions for pam_debathena_home_type.so
 *
 * Copyright © 2007 Tim Abbott <tabbott@mit.edu>
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <syslog.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <errno.h>
#include <security/pam_appl.h>
#include <security/pam_modules.h>
#include <security/pam_misc.h>

#define FS "/usr/bin/fs"

#define MAXBUF 256

/* Initiate session management by updating user's GCONF_CHANGER. */
int
pam_sm_open_session(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
    int i;
    int debug = 0;
    int pamret;
    const char *user;
    struct passwd *pw;
    pid_t pid, newpid;
    int status;
    struct sigaction act, oldact;

    for (i = 0; i < argc; i++) {
        if (strcmp(argv[i], "debug") == 0)
            debug = 1;
    }

    if ((pamret = pam_get_user(pamh, &user, NULL)) != PAM_SUCCESS) {
        syslog(LOG_ERR, "pam_debathena_home_type: pam_get_user: %s:%d",
               pam_strerror(pamh, pamret), pamret);
        return PAM_SESSION_ERR;
    }

    errno = 0;
    pw = getpwnam(user);
    if (pw == NULL) {
        if (errno != 0)
            syslog(LOG_ERR, "pam_debathena_home_type: getpwnam: %s",
                   strerror(errno));
        else
            syslog(LOG_ERR, "pam_debathena_home_type: no such user: %s", user);
        return PAM_SESSION_ERR;
    }
    if (debug)
        syslog(LOG_DEBUG, "pam_debathena_home_type: user=%s home=%s",
               user, pw->pw_dir);

    /* Override gdm's SIGCHLD handler that makes waitpid() return -1.
       Maybe this leads to some race condition if gdm used that at the time? */
    memset(&act, 0, sizeof(act));
    act.sa_handler = SIG_DFL;
    sigaction(SIGCHLD, &act, &oldact);

    pid = fork();
    if (pid < 0) {
        syslog(LOG_ERR, "pam_debathena_home_type: fork(): %s",
               strerror(errno));
        return PAM_SESSION_ERR;
    }
    if (pid == 0) {
        if (debug)
            syslog(LOG_DEBUG, "pam_debathena_home_type: uid=%d euid=%d",
                   getuid(), geteuid());
        if (close(1) < 0) {
            syslog(LOG_ERR, "pam_debathena_home_type: close(): %s",
                   strerror(errno));
            _exit(-1);
        }
        if (close(2) < 0) {
            syslog(LOG_ERR, "pam_debathena_home_type: close(): %s",
                   strerror(errno));
            _exit(-1);
        }
        if (execl(FS, "fs", "whichcell", pw->pw_dir, NULL) < 0) {
            syslog(LOG_ERR, "pam_debathena_home_type: execl(): %s",
                   strerror(errno));
            _exit(-1);
        }
        syslog(LOG_ERR, "pam_debathena_home_type: execl(): %s",
               strerror(errno));
        _exit(-1);
    }
    if (TEMP_FAILURE_RETRY(newpid = waitpid(pid, &status, 0)) == -1 ||
        !WIFEXITED(status)) {
        syslog(LOG_ERR, "pam_debathena_home_type: setup failed: %s:%d %d %s",
               user, status, newpid, strerror(errno));
        return PAM_SESSION_ERR;
    }
    if (WEXITSTATUS(status) == 0) {
        /* If in AFS, setup the GCONF2 hack. */
        if (debug)
            syslog(LOG_DEBUG, "pam_debathena_home_type: AFS homedir %s", user);
        pam_putenv(pamh, "DEBATHENA_HOME_TYPE=afs");
    }
    else {
        if (debug)
            syslog(LOG_DEBUG, "pam_debathena_home_type: Local homedir %s", user);
        pam_putenv(pamh, "DEBATHENA_HOME_TYPE=local");
    }
    if (debug)
        syslog(LOG_DEBUG, "pam_debathena_home_type: succeeded for %s", user);
    sigaction(SIGCHLD, &oldact, NULL);
    return PAM_SUCCESS;
}

int
pam_sm_close_session(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
    return PAM_SUCCESS;
}

int
pam_sm_setcred(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
    return pam_sm_open_session(pamh, flags, argc, argv);
}

int
pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv)
{
    return PAM_IGNORE;
}