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mount_davfs.c

/* 
** Mount the davfs file system.
 */

/*
 *  This file is part of davfs2.
 *
 *  davfs2 is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  davfs2 is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with davfs2; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */


#include "config.h"

#include <argz.h>
#include <ctype.h>
#include <errno.h>
#include <error.h>
#include <fstab.h>
#include <getopt.h>
#include <grp.h>
#include <limits.h>
#include <locale.h>
#include <mntent.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <termios.h>
#include <unistd.h>

#ifdef ENABLE_NLS
#   include <libintl.h>
#   define _(String) gettext(String)
#else
#   define _(String) String
#   define textdomain(Domainname)
#   define bindtextdomain(Domainname, Dirname)
#endif

#include <sys/mount.h>
#include <sys/stat.h>

#include <ne_string.h>
#include <ne_uri.h>

#include "dav_debug.h"
#include "defaults.h"
#include "kernel_interface.h"
#include "cache.h"
#include "webdav.h"
#include "mount_davfs.h"


/* Private global variables */
/*==========================*/

/* The URL of the WebDAV server as taken from commandline.  */
static char *url;

/* The mointpoint as taken from the command line. */
static char *mpoint;

/* The type of the kernel file system used. */
static char *kernel_fs;

/* The file that holds information about mounted filesystems
   (/proc/mounts or /etc/mtab) */
static char *mounts;

/* The PID file */
static char *pidfile;

/* This flags signals the message loop of the kernel interface whether it
   shall do what it says or just stop. Will be reset by termination_handler. */
static volatile int keep_on_running = 1;


/* Private function prototypes */
/*=============================*/

/* Parsing, checking and mounting. */

static void change_persona(dav_args *args);

static void check_dirs(dav_args *args);

static char *check_double_mounts(void);

static void check_fstab(const dav_args *args);

static void check_mountpoint(dav_args *args);

static void check_permissions(dav_args *args);

static int do_mount(unsigned long int mopts, void *mdata);

static int is_mounted(void);

static dav_args *parse_commandline(int argc, char *argv[]);

static void parse_config(dav_args *args);

static void parse_secrets(dav_args *args);

static int save_pid(void);

static void termination_handler(int signo);

static void write_mtab_entry(const dav_args *args);

/* Helper functions. */

static int arg_to_int(const char *arg, int base, const char *opt);

static char *decode_octal(const char *s);

static void delete_args(dav_args *args);

static void eval_modes(dav_args *args);

static void get_options(dav_args *args, char *option);

static int ignore_home(const char *name, const char *ignore_list);

static dav_args *new_args(void);

static int parse_line(char *line, int parmc, char *parmv[]);

static void read_config(dav_args *args, const char * filename, int system);

static void read_secrets(dav_args *args, const char *filename);

static void split_proxy(char **host, int *port, const char *arg);

static void usage(void);


/* Public functions */
/*==================*/

int main(int argc, char *argv[]) {

    setlocale(LC_ALL, "");
    bindtextdomain(PACKAGE, LOCALEDIR);
    textdomain(PACKAGE);

    DBG0("Parsing command line");
    dav_args *args = parse_commandline(argc, argv);

    DBG0("Checking for setuid");
    if (geteuid() != 0)
        error(EXIT_FAILURE, errno, _("program is not setuid root"));
    if (seteuid(getuid()) != 0)
        error(EXIT_FAILURE, errno, _("can't change effective user id"));

    if (getuid() != 0) {
        DBG0("Checking fstab");
        check_fstab(args);
    }

    DBG0("Parsing configuration files");
    parse_config(args);

    DBG0("Checking mount point");
    check_mountpoint(args);

    DBG0("Checking directories");
    check_dirs(args);

    DBG0("Checking permissions");
    check_permissions(args);

    DBG0("Parsing secrets files");
    parse_secrets(args);

    DBG0("Checking for double mounts");
    pidfile = check_double_mounts();

    DBG0("Changing persona:");
    change_persona(args);

    DBG0("Initialize WebDAV-session");    
    dav_init_webdav(args->scheme, args->host, args->port,
                    args->read_timeout, args->locks, args->lock_timeout,
                    args->servercert, args->clicert, args->clicert_pw,
                    args->askauth, args->username, args->password,
                    args->useproxy, args->p_host, args->p_port, args->p_user,
                    args->p_passwd, args->lock_owner, args->displayname,
                    args->expect100, args->s_charset);

    DBG0("Initialize Cache");
    dav_init_cache(args->uid, args->gid, args->file_mode, args->dir_mode,
                   args->file_umask, args->dir_umask, args->table_size,
                   args->dir_refresh, args->file_refresh, args->gui_optimize,
                   args->retry, args->max_retry, args->lock_refresh,
                   args->cache_size, args->cache_dir, args->backup_dir,
                   args->host, args->path, mpoint);

    DBG0("Initialize kernel interface");
    int dev = 0;
    dav_run_msgloop_fn run_msgloop = NULL;
    void *mdata = NULL;
    if (args->kernel_fs != NULL)
        kernel_fs = ne_strdup(args->kernel_fs);
    size_t buf_size = args->buf_size * 1024;
    int mounted = dav_init_kernel_interface(&dev, &run_msgloop, &mdata,
                                            &kernel_fs, &buf_size, url, mpoint,
                                            args->mopts, args->uid, args->gid,
                                            args->dir_mode);

    DBG0("Fork into daemon mode");
    pid_t childpid = fork();
    if (childpid > 0) {

        DBG2("Parent: parent pid: %i, child pid: %i", getpid(), childpid);
        if (!mounted) {
            DBG0("Parent: mounting filesystem");
            if (do_mount(args->mopts, mdata) != 0) {
                kill(childpid, SIGTERM);
                delete_args(args);
                exit(EXIT_FAILURE);
            }
        }

        DBG0("Parent: writing mtab entry");
        write_mtab_entry(args);

        DBG0("Parent: leaving now");
        delete_args(args);
        exit(EXIT_SUCCESS);

    } else if (childpid < 0) {
        delete_args(args);
        error(EXIT_FAILURE, errno, _("can't start daemon process"));
    }

    DBG0("Set signal handler");
    struct sigaction action;
    action.sa_handler = termination_handler;
    sigemptyset(&action.sa_mask);
    sigaddset(&action.sa_mask, SIGTERM);
    sigaddset(&action.sa_mask, SIGHUP);
    action.sa_flags = 0;
    sigaction(SIGTERM, &action, NULL);
    sigaction(SIGHUP, &action, NULL);

    int ret = 0;

    DBG0("Releasing root privileges");
    uid_t daemon_id = geteuid();
    seteuid(0);
    ret = setuid(daemon_id);
    if (ret != 0) {
        syslog(LOG_MAKEPRI(LOG_DAEMON, LOG_ERR),
               _("can't release root privileges"));
        kill(getppid(), SIGHUP);
    }

    time_t idle_time = args->idle_time;
    delete_args(args);
    setsid();

    if (ret == 0) {
        DBG0("Writing pid file");
        ret = save_pid();
        if (ret != 0) {
            syslog(LOG_MAKEPRI(LOG_DAEMON, LOG_ERR),
                   _("can't write pid file %s"), pidfile);
            kill(getppid(), SIGHUP);
        }
    }

    if (ret == 0) {
        DBG0("Starting message loop");
        run_msgloop(dev, buf_size, idle_time, is_mounted, &keep_on_running);
    }

    DBG0("Closing");
    dav_close_cache();
    dav_close_webdav();
    if (is_mounted()) {
        char *prog = ne_concat("/bin/umount -il ", mpoint, NULL);
        syslog(LOG_MAKEPRI(LOG_DAEMON, LOG_ERR), _("unmounting %s"), mpoint);
        if (system(prog) != 0)
            syslog(LOG_MAKEPRI(LOG_DAEMON, LOG_ERR), _("unmounting failed"));
    }
    remove(pidfile);
    return 0;
}


/* Private functions */
/*===================*/

/* Changes the group id of the process permanently to dav_group. The
   effective user id of the process will be changed too, but the real
   user id still has to be changed permanently. */
static void change_persona(dav_args *args) {

    struct group *grp = getgrnam(args->dav_group);
    if (grp == NULL)
        error(EXIT_FAILURE, errno, _("group %s does not exist"),
              args->dav_group);
    seteuid(0);
    if (setgid(grp->gr_gid) != 0)
        error(EXIT_FAILURE, errno, _("can't change group id"));

    if (getuid() == 0) {
        struct passwd *pw = getpwnam(args->dav_user);
        if (pw == NULL)
            error(EXIT_FAILURE, errno, _("user %s does not exist"),
                  args->dav_group);
        if (seteuid(pw->pw_uid) != 0)
            error(EXIT_FAILURE, errno, _("can't change effective user id"));
    
    } else {
        if (seteuid(getuid()) != 0)
            error(EXIT_FAILURE, errno, _("can't change effective user id"));
    }
    DBG2("  euid %i, gid %i", geteuid(), getgid());
}

/* Checks for the existence of necessary and usefull directories and files.
   - checks whether it can use the proc file system for information about
     mounted file systems, or has to use mtab
   - whether the directory to save pid files exists and has correct owner and
     permissions; if not it tries to create it and/or set owner and permissions
   - when invoked by non-root user: checks for configuration directory in the
     users homepage and creates missing directories and files
   - checks wether args->cache_dir is accessible. */
static void check_dirs(dav_args *args) {

    struct stat st;

    if (access(DAV_MOUNTS, R_OK) == 0) {
        mounts = DAV_MOUNTS;
    } else {
        mounts = _PATH_MOUNTED;
    }
    DBG1("Mounts in %s", mounts);

    seteuid(0);
    if (access(DAV_SYS_RUN, F_OK) != 0) {
        if (mkdir(DAV_SYS_RUN, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH | S_ISVTX)
                != 0)
            error(EXIT_FAILURE, errno, _("can't create directory %s"),
                  DAV_SYS_RUN);
    }
    if (stat(DAV_SYS_RUN, &st) != 0)
        error(EXIT_FAILURE, errno, _("can't access directory %s"),
              DAV_SYS_RUN);
    if ((st.st_mode & (S_IRWXG | S_ISVTX)) != (S_IRWXG | S_ISVTX)) {
        if (chmod(DAV_SYS_RUN, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH | S_ISVTX)
                != 0)
            error(EXIT_FAILURE, errno,
                  _("can't change mode of directory %s"), DAV_SYS_RUN);
    }
    struct group *grp = getgrnam(args->dav_group);
    if (grp == NULL)
        error(EXIT_FAILURE, errno, _("group %s does not exist"),
              args->dav_group);
    if (st.st_gid != grp->gr_gid) {
        if (chown(DAV_SYS_RUN, 0, grp->gr_gid) != 0)
            error(EXIT_FAILURE, errno,
                  _("can't change group of directory %s"), DAV_SYS_RUN);
    }
    seteuid(getuid());

    if (getuid() != 0) {

        char *path = NULL;
        struct passwd *pw = getpwuid(getuid());
        if (pw != NULL && pw->pw_dir != NULL)
            path = ne_concat(pw->pw_dir, "/.", PACKAGE, NULL);
        if (path != NULL && access(path, F_OK) != 0)
            mkdir(path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);

        if (path != NULL && access(path, F_OK) == 0) {
            char *dir = ne_concat(path, "/", DAV_CACHE, NULL);
            if (access(dir, F_OK) != 0)
                mkdir(dir, S_IRWXU);
            free(dir);

            dir = ne_concat(path, "/", DAV_CERTS_DIR, NULL);
            if (access(dir, F_OK) != 0)
                mkdir(dir, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
            free(dir);

            dir = ne_concat(path, "/", DAV_CERTS_DIR, "/", DAV_CLICERTS_DIR,
                            NULL);
            if (access(dir, F_OK) != 0)
                mkdir(dir, S_IRWXU);
            free(dir);

            char *file_name = ne_concat(path, "/", DAV_CONFIG, NULL);
            if (access(file_name, F_OK) != 0) {
                char *template = ne_concat(DAV_DATA_DIR, "/", DAV_CONFIG, NULL);
                char *command = ne_concat("cp ", template, " ", file_name,
                                          NULL);
                system(command);
                free(command);
                free(template);
            }
            free(file_name);

            file_name = ne_concat(path, "/", DAV_SECRETS, NULL);
            if (access(file_name, F_OK) != 0) {
                char *template = ne_concat(DAV_DATA_DIR, "/", DAV_SECRETS,
                                           NULL);
                char *command = ne_concat("cp ", template, " ", file_name,
                                          NULL);
                if (system(command) == 0)
                    chmod(file_name, S_IRUSR | S_IWUSR);
                free(command);
                free(template);
            }
            free(file_name);
        }
        free(path);
    }

    if (strcmp(args->cache_dir, args->sys_cache) == 0) {

        seteuid(0);
        if (access(args->sys_cache, F_OK) != 0) {
            if (mkdir(args->sys_cache, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH)
                    != 0)
                error(EXIT_FAILURE, errno, _("can't create directory %s"),
                      args->sys_cache);
        }
        if (stat(args->sys_cache, &st) != 0)
            error(EXIT_FAILURE, errno, _("can't access directory %s"),
                  args->sys_cache);
        if ((st.st_mode & S_IRWXG) != S_IRWXG) {
            if (chmod(args->sys_cache, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH)
                    != 0)
                error(EXIT_FAILURE, errno,
                      _("can't change mode of directory %s"),
                      args->sys_cache);
        }
        struct group *grp = getgrnam(args->dav_group);
        if (grp == NULL)
            error(EXIT_FAILURE, errno, _("group %s does not exist"),
                  args->dav_group);
        if (st.st_gid != grp->gr_gid) {
            if (chown(args->sys_cache, 0, grp->gr_gid) != 0)
                error(EXIT_FAILURE, errno,
                      _("can't change group of directory %s"),
                      args->sys_cache);
        }
        seteuid(getuid());

    } else {

        struct passwd *pw = getpwuid(getuid());
        if (pw == NULL)
            error(EXIT_FAILURE, errno, _("can't read user data base"));
        if (pw->pw_name == NULL)
            error(EXIT_FAILURE, 0, _("can't read user data base"));
        if (access(args->cache_dir, F_OK) != 0) {
            if (mkdir(args->cache_dir, S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH)
                    != 0)
                error(EXIT_FAILURE, errno, _("can't create directory %s"),
                      args->cache_dir);
        }
        if (stat(args->cache_dir, &st) != 0)
            error(EXIT_FAILURE, errno, _("can't access directory %s"),
                  args->cache_dir);
        if ((st.st_uid != getuid() || (st.st_mode & S_IRWXU) != S_IRWXU)
                &&  (st.st_mode & S_IRWXO) != S_IRWXO) {
            if ((st.st_mode & S_IRWXG) != S_IRWXG)
                error(EXIT_FAILURE, errno, _("can't access directory %s"),
                      args->cache_dir);
            struct group *grp = getgrgid(st.st_gid);
            if (grp == NULL)
                error(EXIT_FAILURE, errno, _("can't read group data base"));
            char **members = grp->gr_mem;
            while (*members != NULL && strcmp(*members, pw->pw_name) != 0)
                members++;
            if (*members == NULL)
                error(EXIT_FAILURE, 0, _("can't access directory %s"),
                args->cache_dir);
        }

    }
}


/* Checks whether url is already mounted on mpoint, creates the name of the
   pid file and checks whether it already exists.
   If one of these tests is positive, it prints an error message and
   terminates the program. Otherwise it returns the name of the pid file.
   return value : the name of the pid file. */
static char *check_double_mounts(void) {

    FILE *mtab = setmntent(mounts, "r");
    if (mtab == NULL)
        error(EXIT_FAILURE, errno, _("can't open file %s"), mounts);
    struct mntent *mt = getmntent(mtab);
    while (mt != NULL) {
        if (strcmp(mpoint, mt->mnt_dir) == 0
                    && strcmp(url, mt->mnt_fsname) == 0)
        error(EXIT_FAILURE, 0, _("%s is already mounted on %s"), url,
              mpoint);
        mt = getmntent(mtab);
    }
    endmntent(mtab);

    char *m = mpoint;
    while (*m == '/')
        m++;
    char *mp = ne_strdup(m);
    m = strchr(mp, '/');
    while (m != NULL) {
        *m = '-';
        m = strchr(mp, '/');
    }
    char *pidf = NULL;
    if (asprintf(&pidf, "%s/%s.pid", DAV_SYS_RUN, mp) < 0)
        abort();
    DBG1("PID file: %s", pidf);

    FILE *file = fopen(pidf, "r");
    if (file != NULL)
        error(EXIT_FAILURE, 0, _("found PID file %s.\n"
              "Either %s is used by another process,\n"
              "or another mount process ended irregular"), pidf, mpoint);

    return pidf;
}


/* Checks fstab whether there is an entry for the mountpoint specified in args
   and compares the values in args with the values in fstab.
   If there is no such entry, or this entry does not allow user-mount, or the
   values differ, an error message is printed and the program terminates.
   Option useproxy, askauth and locks are not checked. The mounting user is
   free to choose them. They should be configured in davfs2.conf anyway. */
static void check_fstab(const dav_args *args) {

    dav_args *n_args = new_args();
    n_args->mopts = DAV_USER_MOPTS;

    setfsent();
    struct fstab *ft = getfsfile(mpoint);
    if (ft == NULL)
        error(EXIT_FAILURE, 0, _("no entry for %s found in %s"), url,
              _PATH_FSTAB);

    if (strcmp(url, ft->fs_spec) != 0) {
        char *fstab_url = decode_octal(ft->fs_spec);
        if (strcmp(url, fstab_url) != 0)
            error(EXIT_FAILURE, 0, _("different URL in %s"), _PATH_FSTAB);
        free(fstab_url);
    }

    if (ft->fs_mntops != NULL)
        get_options(n_args, ft->fs_mntops);

    if (strcmp(DAV_FS_TYPE, ft->fs_vfstype) != 0)
        error(EXIT_FAILURE, 0, _("different file system type in %s"),
              _PATH_FSTAB);
    if (strcmp(args->conf, n_args->conf) != 0)
        error(EXIT_FAILURE, 0, _("different config file in %s"), _PATH_FSTAB);
    if (n_args->user != 1)
        error(EXIT_FAILURE, 0, _("option `user' not set in %s"), _PATH_FSTAB);
    if (args->mopts != n_args->mopts)
        error(EXIT_FAILURE, 0, _("different mount options in %s"),
              _PATH_FSTAB);
    if (args->uid != n_args->uid)
        error(EXIT_FAILURE, 0, _("different uid in %s"), _PATH_FSTAB);
    if (args->gid != n_args->gid)
        error(EXIT_FAILURE, 0, _("different gid in %s"), _PATH_FSTAB);
    if (args->dir_mode != n_args->dir_mode)
        error(EXIT_FAILURE, 0, _("different dir_mode in %s"), _PATH_FSTAB);
    if (args->file_mode != n_args->file_mode)
        error(EXIT_FAILURE, 0, _("different file_mode in %s"), _PATH_FSTAB);

    endfsent();
    delete_args(n_args);
}


/* Checks if a valid mountpoint is specified.
   For non root users this must meet the additional conditions:
   - if the mount point is given as relative path, it must lie within
     the mounting users home directory (so a relative path in fstab
     - which might be useful in some cases - will not allow to to
     gain access to directories not intended).
   - if given as an absulute path it must not lie within another users
     home directory (even the administrator can't give the right to mount
     into another users home directory).
   If this conditions are not met or an error occurs, an error message is
   printed and exit(EXIT_FAILURE) is called. */
static void check_mountpoint(dav_args *args) {

    struct passwd *pw;

    if (*mpoint != '/') {
        char *mp = canonicalize_file_name(mpoint);
        if (mp == NULL)
            error(EXIT_FAILURE, 0,
                  _("can't evaluate path of mount point %s"), mpoint);
        if (getuid() != 0) {
            pw = getpwuid(getuid());
            if (pw == NULL || pw->pw_dir == NULL)
                error(EXIT_FAILURE, 0,
                      _("can't get home directory for uid %i"), getuid());
            if (strstr(mp, pw->pw_dir) != mp)
                error(EXIT_FAILURE, 0, _("A relative mount point must lie "
                      "within your home directory"));
        }
        free(mpoint);
        mpoint = mp;
    }

    if (strcmp(mpoint, "/") == 0 || strlen(mpoint) < 2)
        error(EXIT_FAILURE, 0, _("invalid mount point %s"), mpoint);

    if (access(mpoint, F_OK) != 0)
        error(EXIT_FAILURE, 0, _("mount point %s does not exist"), mpoint);

    if (getuid() != 0) {
        pw = getpwuid(getuid());
        if (pw == NULL)
            error(EXIT_FAILURE, errno, _("can't read user data base"));
        if (pw->pw_dir == NULL)
            error(EXIT_FAILURE, 0, _("can't read user data base"));
        if(strstr(mpoint, pw->pw_dir) != mpoint) {
            setpwent();
            pw = getpwent();
            while (pw != NULL) {
                if (pw->pw_dir == NULL || pw->pw_name == NULL)
                    error(EXIT_FAILURE, 0, _("can't read user data base"));
                if (pw->pw_uid != args->uid && strlen(pw->pw_dir) > 0
                        && strstr(mpoint, pw->pw_dir) == mpoint
                        && !ignore_home(pw->pw_name, args->ignore_home))
                    error(EXIT_FAILURE, 0,
                          _("%s is the home directory of user %s.\n"
                          "You can't mount into another users home directory"),
                          pw->pw_dir, pw->pw_name);
                pw = getpwent();
            }
            endpwent();
        }
    }

    DBG1("  Mountpoint: %s", mpoint);
}


/* The mounting user must be either root or meet the following conditions:
   - The  uid must not differ from the option uid, if this option is used.
   - The user must belong to the group specified in option gid (if used).
   - The user must be member of group args->dav_group.
   If this conditions are not met or an error occurs, an error message is
   printed and exit(EXIT_FAILURE) is called. */
static void check_permissions(dav_args *args) {

    if (getuid() == 0)
        return;

    DBG0("  Checking uid.");
    if (args->uid != getuid())
        error(EXIT_FAILURE, 0,
              _("you can't set file owner different from your uid"));

    DBG0("  Checking gid.");
    if (getgid() != args->gid) {
        struct passwd *pw = getpwuid(getuid());
        if (pw == NULL)
            error(EXIT_FAILURE, errno, _("can't read user data base"));
        if (pw->pw_name == NULL)
            error(EXIT_FAILURE, 0, _("can't read user data base"));
        struct group *grp = getgrgid(args->gid);
        if (grp == NULL)
            error(EXIT_FAILURE, 0, _("can't read group data base"));
        char **members = grp->gr_mem;
        while (*members != NULL && strcmp(*members, pw->pw_name) != 0)
            members++;
        if (*members == NULL)
            error(EXIT_FAILURE, 0,
                  _("you must be member of the group of the file system"));
    }

    DBG1("  Checking membership in group %s.", args->dav_group);
    struct passwd *pw;
    pw = getpwuid(getuid());
    if (pw == NULL)
        error(EXIT_FAILURE, errno, _("can't read user data base"));
    if (pw->pw_name == NULL)
        error(EXIT_FAILURE, 0, _("can't read user data base"));
    struct group *grp = getgrnam(args->dav_group);
    if (grp == NULL)
        error(EXIT_FAILURE, errno, _("group %s does not exist"),
              args->dav_group);
    if (pw->pw_gid != grp->gr_gid) {
        char **members = grp->gr_mem;
        while (*members != NULL && strcmp(*members, pw->pw_name) != 0)
            members++;
        if (*members == NULL)
            error(EXIT_FAILURE, 0, _("user %s must be member of group %s"),
                  pw->pw_name, grp->gr_name);
    }
}


/* Calls the mount()-function to mount the file system.
   Uses private global variables url and mpoint as device and mount point,
   kernel_fs as file system type, mopts as mount options and mdata
   as mount data.
   return value : 0 on success, -1 if mount() fails. */
static int do_mount(unsigned long int mopts, void *mdata) {

    uid_t orig = geteuid();
    seteuid(0);
    int ret = mount(url, mpoint, kernel_fs,  mopts, mdata);
    seteuid(orig);

    if (ret != 0) {
        error(0, errno, _("can't mount %s on %s"), url, mpoint);
        if (errno == ENODEV)
            error(0, 0, _("kernel does not know file system %s"), kernel_fs);
        if (errno == EBUSY)
            error(0, 0, _("mount point is busy"));
        return -1;
    }
    return 0;
}


/* Checks wether the file system is mounted.
   It uses information from the private global variables mounts (mtab-file),
   url (must be device in the mtab entry) and mpoint (mount point).
   return value : 0 - no matching entry in the mtab-file (not mounted)
                  1 - matching entry in the mtab-file (mounted) */
static int is_mounted(void) {

    int found = 0;
    FILE *mtab = setmntent(mounts, "r");
    if (mtab != NULL) {
        struct mntent *mt = getmntent(mtab);
        while (mt != NULL && found == 0) {
            if (strcmp(mpoint, mt->mnt_dir) == 0
                        && strcmp(url, mt->mnt_fsname) == 0)
                found = 1;
            mt = getmntent(mtab);
        }
    }
    endmntent(mtab);
    return found;
}

/* Parses commandline arguments and options and stores them in args and the
   private global variables url and mpoint.
   For arguments and options please see the usage()-funktion.
   As soon as 'version' or 'help' is found, an appropriate message is printed
   and exit(EXIT_SUCCESS) is called.
   If it does not find exactly two non-option-arguments (url and mointpoint)
   it prints an error message and calls exit(EXIT_FAILURE).
   argc    : the number of arguments.
   argv[]  : array of argument strings.
   return value : args, containig the parsed options and arguments. The args
                  structure and all strings are newly allocated. The calling
                  function is responsible to free them. */
static dav_args *parse_commandline(int argc, char *argv[]) {

    DBG_CMDLINE(argv);

    dav_args *args = new_args();

    char *short_options = "vwVho:";
    static const struct option options[] = {
        {"version", no_argument, NULL, 'V'},
        {"help", no_argument, NULL, 'h'},
        {"option", required_argument, NULL, 'o'},
        {0, 0, 0, 0}
    };

    int o;
    o = getopt_long(argc, argv, short_options, options, NULL);
    while (o != -1) {
        switch (o) {
        case 'V':
            printf("%s  <%s>\n\n", PACKAGE_STRING, DAV_HOME);
            printf(_("This is free software; see the source for copying "
                     "conditions.  There is NO\n"
                     "warranty; not even for MERCHANTABILITY or FITNESS "
                     "FOR A PARTICULAR PURPOSE.\n"));
            exit(EXIT_SUCCESS);
        case 'h':
            usage();
            exit(EXIT_SUCCESS);
        case 'o':
            get_options(args, optarg);
            break;
        case 'v':
        case 'w':
        case '?':
            break;
        default:
            error(EXIT_FAILURE, 0, _("unknown error parsing arguments"));
        }
        o = getopt_long(argc, argv, short_options, options, NULL);
    }

    int i = optind;
    switch (argc - i) {
    case 0:
    case 1:
        error(0, 0, _("missing argument"));
        usage();
        exit(EXIT_FAILURE);
    case 2:
        if (*argv[i] == '\"' || *argv[i] == '\'') {
            url = ne_strndup(argv[i] + 1, strlen(argv[i]) -2);
        } else {
            url = ne_strdup(argv[i]);
        }
        i++;
        mpoint = ne_strdup(argv[i]);
        break;
    default:
        error(0, 0, _("too many arguments"));
        usage();
        exit(EXIT_FAILURE);
    }

    if (mpoint == NULL)
        error(EXIT_FAILURE, 0, _("no mountpoint specified"));
    while (strlen(mpoint) > 1 && *(mpoint + strlen(mpoint) -1) == '/')
        *(mpoint + strlen(mpoint) -1) = '\0';

    if (url == NULL)
        error(EXIT_FAILURE, 0, _("no WebDAV-server specified"));
    ne_uri *uri = (ne_uri *) ne_malloc(sizeof(ne_uri));
    if (ne_uri_parse(url, uri) != 0 || uri->host == NULL
            || uri->path == NULL)
        error(EXIT_FAILURE, 0, _("invalid URL"));

    if (uri->scheme != NULL) {
        args->scheme = uri->scheme;
        uri->scheme = NULL;
    } else {
        args->scheme = ne_strdup("http");
    }

    args->host = uri->host;
    uri->host = NULL;
    if (uri->port != 0) {
        args->port = uri->port;
    } else {
        args->port = ne_uri_defaultport(args->scheme);
    }

    if (strlen(uri->path) < 1
            || *(uri->path + strlen(uri->path) -1) != '/') {
        args->path = ne_concat(uri->path, "/", NULL);
    } else {
        args->path = uri->path;
        uri->path = NULL;
    }

    ne_uri_free(uri);
    free(uri);
    DBG1("  URL: %s", url);
    DBG1("  Mount point: %s", mpoint);

    return args;       
}


/* Reads and parses the configuration files and stores the values in args.
   The system wide configuration file is parsed first. If args->conf is
   given it will be parsed too and overwrites the values from the system
   wide configuration file. */
static void parse_config(dav_args *args) {

    read_config(args, DAV_SYS_CONF_DIR "/" DAV_CONFIG, 1);

    struct passwd *pw = getpwuid(getuid());
    if (pw == NULL || pw->pw_dir == NULL)
        error(EXIT_FAILURE, 0, _("can't determine home directory"));

    if (args->conf != NULL) {
        if (*args->conf == '~') {
            int p = 1;
            if (*(args->conf + p) == '/')
                p++;
            char *f = ne_concat(pw->pw_dir, "/", args->conf + p, NULL);
            free(args->conf);
            args->conf = f;
        }
        read_config(args, args->conf, 0);
    }

    args->mopts |= DAV_MOPTS;

    eval_modes(args);

    if (args->servercert != NULL && *args->servercert == '~') {
        int p = 1;
        if (*(args->servercert + p) == '/')
            p++;
        char *f = ne_concat(pw->pw_dir, "/", args->servercert + p, NULL);
        free(args->servercert);
        args->servercert = f;
    }
    if (args->servercert != NULL && *args->servercert != '/' && getuid() != 0) {
        char *f = ne_concat(pw->pw_dir, "/", DAV_CERTS_DIR, "/",
                            args->servercert, NULL);
        if (access(f, F_OK) == 0) {
            free(args->servercert);
            args->servercert = f;
        } else {
            free(f);
        }
    }
    if (args->servercert != NULL && *args->servercert != '/') {
        char *f = ne_concat(DAV_SYS_CONF_DIR, "/", DAV_CERTS_DIR, "/",
                            args->servercert, NULL);
        free(args->servercert);
        args->servercert = f;
    }

    if (args->secrets != NULL && *args->secrets == '~') {
        int p = 1;
        if (*(args->secrets + p) == '/')
            p++;
        char *f = ne_concat(pw->pw_dir, "/", args->secrets + p, NULL);
        free(args->secrets);
        args->secrets = f;
    }

    if (args->clicert != NULL && *args->clicert == '~') {
        int p = 1;
        if (*(args->clicert + p) == '/')
            p++;
        char *f = ne_concat(pw->pw_dir, "/", args->clicert + p, NULL);
        free(args->clicert);
        args->clicert = f;
    }
    if (args->clicert != NULL && *args->clicert != '/' && getuid() != 0) {
        char *f = ne_concat(pw->pw_dir, "/", DAV_CERTS_DIR, "/",
                            DAV_CLICERTS_DIR, "/", args->clicert, NULL);
        if (access(f, F_OK) == 0) {
            free(args->clicert);
            args->clicert = f;
        }
    }
    if (args->clicert != NULL && *args->clicert != '/' && getuid() == 0) {
        char *f = ne_concat(DAV_SYS_CONF_DIR, "/", DAV_CERTS_DIR, "/",
                            DAV_CLICERTS_DIR, "/", args->clicert, NULL);
        free(args->clicert);
        args->clicert = f;
    }
    if (args->clicert != NULL) {
        struct stat st;
        seteuid(0);
        if (stat(args->clicert, &st) < 0)
            error(EXIT_FAILURE, 0, _("can't read client certificate %s"),
                  args->clicert);
        seteuid(getuid());
        if (st.st_uid != getuid() && st.st_uid != 0)
            error(EXIT_FAILURE, 0,
                  _("client certificate file %s has wrong owner"),
                  args->clicert);
        if ((st.st_mode &
                (S_IXUSR | S_IRWXG | S_IRWXO | S_ISUID | S_ISGID | S_ISVTX))
                != 0)
            error(EXIT_FAILURE, 0,
                  _("client certificate file %s has wrong permissions"),
                  args->clicert);
    }

    if (args->p_host == NULL)
        args->useproxy = 0;

    if (args->cache_dir == NULL) {
        args->cache_dir = ne_strdup(args->sys_cache);
    } else if (*args->cache_dir == '~') {
        int p = 1;
        if (*(args->cache_dir + p) == '/')
            p++;
        char *f = ne_concat(pw->pw_dir, "/", args->cache_dir + p, NULL);
        free(args->cache_dir);
        args->cache_dir = f;
    }

    DBG_ARGS;
}


/* Reads the secrets file and asks the user interactivly for credentials if
   necessary. The user secrets file is parsed after the system wide secrets
   file, so it will have precedence. */
static void parse_secrets(dav_args *args) {

    seteuid(0);
    read_secrets(args, DAV_SYS_CONF_DIR "/" DAV_SECRETS);
    seteuid(getuid());

    if (args->secrets != NULL) {
        read_secrets(args, args->secrets);
    }

    char *s = NULL;
    size_t n = 0;
    ssize_t len = 0;

    if (args->askauth && args->useproxy && args->p_user == NULL) {
        printf(_("Please enter the username to authenticate with proxy\n"
                 "%s or hit enter for none.\nUsername: "), args->p_host);
        len = getline(&s, &n, stdin);
        if (len < 1)
            abort();
        if (len > 1) {
            args->p_user = ne_strndup(s, len - 1);
            memset(s, '\0', len - 1);
        }
        free(s);
        s = NULL;
    }

    if (args->askauth && args->useproxy && args->p_user != NULL
            && args->p_passwd == NULL) {
        printf(_("Please enter the password to authenticate user %s with proxy\n"
                 "%s or hit enter for none.\n"), args->p_user, args->p_host);
        args->p_passwd = getpass(_("Password: "));
        if (args->p_passwd != NULL && strlen(args->p_passwd) == 0) {
            free(args->p_passwd);
            args->p_passwd = NULL;
        }
    }

    if (args->askauth && args->username == NULL) {
        printf(_("Please enter the username to authenticate with server\n"
                 "%s or hit enter for none.\nUsername: "), url);
        len = getline(&s, &n, stdin);
        if (len < 1)
            abort();
        if (len > 1) {
            args->username = ne_strndup(s, len - 1);
            memset(s, '\0', len - 1);
        }
        free(s);
    }

    if (args->askauth && args->username != NULL && args->password == NULL) {
        printf(_("Please enter the password to authenticate user %s with "
                 "server\n%s or hit enter for none.\n"), args->username, url);
        args->password = getpass(_("Password: "));
        if (args->password != NULL && strlen(args->password) == 0) {
            free(args->password);
            args->password = NULL;
        }
    }

    DBG_SECRETS;
}


/* Saves the pid of the mount.davfs daemon in the pid-file. The name of the
   pid-file is taken from the private global variable pidfile. If an error
   occurs during opening of the pid-file, the function returns with -1. */
static int save_pid(void) {

    FILE *file = fopen(pidfile, "w");
    if (file == NULL)
        return -1;
    int ret = 0;
    if (fprintf(file, "%i\n", getpid()) <= 0)
        ret = -1;
    fclose(file);
    chmod(pidfile, S_IRWXU | S_IRGRP | S_IROTH);
    return ret;
}


/* Signal handler for the daemon process.
   Stops the daemon process by calling the umount program. Additionally it
   sets global variable *keep_on_running to 0, so the daemon will stop even
   if umount fails. */
static void termination_handler(int signo) {

    syslog(LOG_MAKEPRI(LOG_DAEMON, LOG_ERR), _("pid %i, got singal %i"),
                       getpid(), signo);
    if (is_mounted()) {
        char *prog = ne_concat("/bin/umount ", mpoint, NULL);
        syslog(LOG_MAKEPRI(LOG_DAEMON, LOG_ERR), _("unmounting %s"), mpoint);
        if (system(prog) != 0)
            syslog(LOG_MAKEPRI(LOG_DAEMON, LOG_ERR), _("unmounting failed"));
        free(prog);
    }

    keep_on_running = 0;
}


/* Adds an entry to _PATH_MOUNTED for the mounted file system.
   If this fails a warning will be printed, but this will not stop mounting. */
static void write_mtab_entry(const dav_args *args) {

    struct mntent mntent;
    mntent.mnt_fsname = url;
    mntent.mnt_dir = mpoint;
    mntent.mnt_type = DAV_FS_TYPE;
    mntent.mnt_opts = NULL;
    asprintf(&mntent.mnt_opts, "%s%s%s%s%s%s",
             (args->mopts & MS_RDONLY) ? "ro" : "rw",
             (args->mopts & MS_NOSUID) ? ",nosuid" : "",
             (args->mopts & MS_NOEXEC) ? ",noexec" : "",
             (args->mopts & MS_NODEV) ? ",nodev" : "",
             (args->netdev) ? ",_netdev" : "",
             (args->add_mopts != NULL) ? args->add_mopts : "");
    if (mntent.mnt_opts == NULL)
        abort();
    mntent. mnt_freq = 0;
    mntent. mnt_passno = 0;

    if (getuid() != 0) {
        struct passwd *pw = getpwuid(getuid());
        if (pw == NULL) {
            error(0, errno, _("Warning: can't read user data base. Mounting "
                              "anyway, but there is no entry in mtab."));
            return;
        }
        char *opts = mntent.mnt_opts;
        mntent.mnt_opts = ne_concat(opts, ",user=", pw->pw_name, NULL);
        free(opts);
    }

    uid_t orig = geteuid();
    seteuid(0);
    int ret;
    FILE *mtab = setmntent(_PATH_MOUNTED, "a");
    if (mtab != NULL) {
        ret = addmntent(mtab, &mntent);
        endmntent(mtab);
    } else {
        error(0, 0, _("Warning: can_t write entry into mtab, but will mount "
                      "the file system anyway"));
    }
    seteuid(orig);

    free(mntent.mnt_opts);
}


/* Helper functions. */

/* Searches arg from the beginning for digits, valid in base, and converts
   them to an integer. If arg does not start with valid digits an error
   message is printed and exit(EXIT_FAILURE) is called.
   Otherwise the integer is returned.
   arg    : string to be converted
   base   : radix of the number; value between 2 and 36
   opt    : name of the option, arg belongs to. Used in the error message.
   return value: the value of the integer number in arg */
static int arg_to_int(const char *arg, int base, const char *opt) {

    char *tail = NULL;
    int n = strtol(arg, &tail, base);
    if (n < 0 || tail == NULL) {
        if (base == 10) {
            error(EXIT_FAILURE, 0, _("option %s has invalid argument;"
                                     "it must be a decimal number"), opt);
        } else if (base == 8) {
            error(EXIT_FAILURE, 0, _("option %s has invalid argument;"
                                     "it must be an octal number"), opt);
        } else {
            error(EXIT_FAILURE, 0, _("option %s has invalid argument;"
                                     "it must be a number"), opt);
        }
    }

    return n;
}


/* Searches string s for octal encoded characters (like \040 for space).
   It returns a new string where these have been replaced by the
   respective characters. */
static char *decode_octal(const char *s) {

    const char *old = s;
    char *decoded = calloc(strlen(s) +1, 1);
    if (decoded == NULL)
        abort();
    while (*old != '\0') {
        char *pos = strstr(old, "\\0");
        if (pos != NULL) {
            char *tail;
            int c = strtol(pos + 1, &tail, 8);
            if ((tail - pos) == 4 && c != 0 && c >= CHAR_MIN && c <= CHAR_MAX) {
                strncat(decoded, old, pos - old);
                *(decoded + strlen(decoded)) = c;
                old = tail;
            } else {
                pos += 2;
                strncat(decoded, old, pos - old);
                old = pos;
            }
        } else {
            strcat(decoded, old);
            old += strlen(old);
        }
    }
    
    return decoded;
}

/* Frees all strings held by args and finally frees args. */
static void delete_args(dav_args *args) {

    if (args->dav_user != NULL)
        free(args->dav_user);
    if (args->dav_group != NULL)
        free(args->dav_group);
    if (args->ignore_home != NULL)
        free(args->ignore_home);
    if (args->conf != NULL)
        free(args->conf);
    if (args->add_mopts != NULL)
        free(args->add_mopts);
    if (args->kernel_fs != NULL)
        free(args->kernel_fs);
    if (args->scheme != NULL)
        free(args->scheme);
    if (args->host != NULL)
        free(args->host);
    if (args->path != NULL)
        free(args->path);
    if (args->servercert != NULL)
        free(args->servercert);
    if (args->secrets != NULL)
        free(args->secrets);
    if (args->username != NULL) {
        memset(args->username, '\0', strlen(args->username));
        free(args->username);
    }
    if (args->password != NULL) {
        memset(args->password, '\0', strlen(args->password));
        free(args->password);
    }
    if (args->clicert != NULL)
        free(args->clicert);
    if (args->clicert_pw != NULL) {
        memset(args->clicert_pw, '\0', strlen(args->clicert_pw));
        free(args->clicert_pw);
    }
    if (args->p_host != NULL)
        free(args->p_host);
    if (args->p_user != NULL) {
        memset(args->p_user, '\0', strlen(args->p_user));
        free(args->p_user);
    }
    if (args->p_passwd != NULL) {
        memset(args->p_passwd, '\0', strlen(args->p_passwd));
        free(args->p_passwd);
    }
        free(args->p_passwd);
    if (args->s_charset != NULL)
        free(args->s_charset);
    if (args->sys_cache != NULL)
        free(args->sys_cache);
    if (args->cache_dir != NULL)
        free(args->cache_dir);
    if (args->backup_dir != NULL)
        free(args->backup_dir);
    if (args->lock_owner != NULL)
        free(args->lock_owner);
    free(args);
}


/* Evaluates the umask and thedefault modes for directories and files from
   args->mopts, umask(), args->dir_mode and args->file_mode and stores them
   in args. */
static void eval_modes(dav_args *args) {

    if (args->mopts & MS_NOSUID)
        args->dir_umask = S_ISUID | S_ISGID;
    if (args->mopts & MS_RDONLY)
        args->dir_umask |= S_IWUSR | S_IWGRP | S_IWOTH;

    args->file_umask = args->dir_umask;
    if (args->mopts & MS_NOEXEC)
        args->file_umask |= S_IXUSR | S_IXGRP | S_IXOTH;

    mode_t default_mode = umask(0);
    umask(default_mode);
    default_mode = ~default_mode;
    default_mode &= S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;

    if (args->dir_mode == 0) {
        args->dir_mode = default_mode;
        args->dir_mode |= (args->dir_mode & S_IRUSR) ? S_IXUSR : 0;
        args->dir_mode |= (args->dir_mode & S_IRGRP) ? S_IXGRP : 0;
        args->dir_mode |= (args->dir_mode & S_IROTH) ? S_IXOTH : 0;
    }
    args->dir_mode &= ~args->dir_umask;
    args->dir_mode |= S_IFDIR;

    if (args->file_mode == 0)
        args->file_mode = default_mode;
    args->file_mode &= ~args->file_umask;
    args->file_mode |= S_IFREG;
}


/* Parses the string option and stores the values in the appropriate fields of
   args. If an unknown option is found exit(EXIT_FAILURE) is called.
   All strings returned in args are newly allocated, and the calling function
   is responsible to free them.
   option : a comma separated list of options (like the options in fstab and
            in the -o option of the mount-programm).
            For known options see the declaration at the beginning of the
            the function definition. */
static void get_options(dav_args *args, char *option) {

    enum {
        CONF = 0,
        UID,
        GID,
        FILE_MODE,
        DIR_MODE,
        USEPROXY,
        NOUSEPROXY,
        ASKAUTH,
        NOASKAUTH,
        LOCKS,
        NOLOCKS,
        USER,
        NOUSER,
        NETDEV,
        NONETDEV,
        RW,
        RO,
        SUID,
        NOSUID,
        EXEC,
        NOEXEC,
        DEV,
        NODEV,
        ASYNC,
        AUTO,
        NOAUTO,
        DEFAULTS,
        END
    };
    char *suboptions[] = {
        [CONF] = "conf",
        [UID] = "uid",
        [GID] = "gid",
        [FILE_MODE] = "file_mode",
        [DIR_MODE] = "dir_mode",
        [USEPROXY] = "useproxy",
        [NOUSEPROXY] = "nouseproxy",
        [ASKAUTH] = "askauth",
        [NOASKAUTH] = "noaskauth",
        [LOCKS] = "locks",
        [NOLOCKS] = "nolocks",
        [USER] = "user",
        [NOUSER] = "nouser",
        [NETDEV] = "_netdev",
        [NONETDEV] = "no_netdev",
        [RW] = "rw",
        [RO] = "ro",
        [SUID] = "suid",
        [NOSUID] = "nosuid",
        [EXEC] = "exec",
        [NOEXEC] = "noexec",
        [DEV] = "dev",
        [NODEV] = "nodev",
        [ASYNC] = "async",
        [AUTO] = "auto",
        [NOAUTO] = "noauto",
        [DEFAULTS] = "defaults",
        [END] = NULL
    };

    int so;
    char *argument = NULL;
    struct passwd *pwd;
    struct group *grp;
    char *add_mopts = NULL;

    while (*option != 0) {
        so = getsubopt(&option, suboptions, &argument);
        if ((argument == NULL) && (so < USEPROXY))
            error(EXIT_FAILURE, 0,
                 _("option %s requires argument"), suboptions[so]);
        switch (so) {
        case CONF:
            if (args->conf != NULL)
                free(args->conf);
            args->conf = ne_strdup(argument);
        case UID:
            pwd = getpwnam(argument);
            if (pwd == NULL) {
                args->uid = arg_to_int(argument, 10, suboptions[so]);
            } else {
                args->uid = pwd->pw_uid;
            }
            asprintf(&add_mopts, "%s,uid=%i",
                     (args->add_mopts != NULL) ? args->add_mopts : "",
                     args->uid);
            if (add_mopts == NULL)
                abort();
            if (args->add_mopts != NULL)
                free(args->add_mopts);
            args->add_mopts = add_mopts;
            add_mopts = NULL;
            break;
        case GID:
            grp = getgrnam(argument);
            if (grp == NULL) {
                args->gid = arg_to_int(argument, 10, suboptions[so]);
            } else {
                args->gid = grp->gr_gid;
            }
            asprintf(&add_mopts, "%s,gid=%i",
                     (args->add_mopts != NULL) ? args->add_mopts : "",
                     args->gid);
            if (add_mopts == NULL)
                abort();
            if (args->add_mopts != NULL)
                free(args->add_mopts);
            args->add_mopts = add_mopts;
            add_mopts = NULL;
            break;
        case FILE_MODE:
            args->file_mode = arg_to_int(argument, 8, suboptions[so]);
            break;
        case DIR_MODE:
            args->dir_mode = arg_to_int(argument, 8, suboptions[so]);
            break;
        case USEPROXY:
            args->useproxy = 1;
            break;
        case NOUSEPROXY:
            args->useproxy = 0;
            break;
        case ASKAUTH:
            args->askauth = 1;
            break;
        case NOASKAUTH:
            args->askauth = 0;
            break;
        case LOCKS:
            args->locks = 1;
            break;
        case NOLOCKS:
            args->locks = 0;
            break;
        case USER:
            args->user = 1;
            break;
        case NOUSER:
            args->user = 0;
            break;
        case NETDEV:
            args->netdev = 1;
            break;
        case NONETDEV:
            args->netdev = 0;
            break;
        case RW:
            args->mopts &= ~MS_RDONLY;
            break;
        case RO:
            args->mopts |= MS_RDONLY;
            break;
        case SUID:
            args->mopts &= ~MS_NOSUID;
            break;
        case NOSUID:
            args->mopts |= MS_NOSUID;
            break;
        case EXEC:
            args->mopts &= ~MS_NOEXEC;
            break;
        case NOEXEC:
            args->mopts |= MS_NOEXEC;
            break;
        case DEV:
            args->mopts &= ~MS_NODEV;
            break;
        case NODEV:
            args->mopts |= MS_NODEV;
            break;
        case ASYNC:
        case AUTO:
        case NOAUTO:
        case DEFAULTS:
            break;
        default:
            if (so == -1) {
                printf(_("Unknown option %s.\n"), argument);
                usage();
                exit(EXIT_FAILURE);
            }
        }
    }
}


/* Checks whether name ist in ignore_list.
   name        : name of a system user. Must not be NULL.
   ignore_list : comma seperated list of system users. May be NULL.
   return value : 1 if name is in ignore_list, 0 otherwise. */
static int ignore_home(const char *name, const char *ignore_list) {

    if (ignore_list == NULL)
        return 0;
    char * s = strstr(ignore_list, name);
    if (s == NULL)
        return 0;
    if (s != ignore_list && *(s - 1) != ',')
        return 0;
    if (*(s + strlen(name)) != '\0' && *(s + strlen(name)) != ',')
        return 0;
    return 1;
}


/* Allocates a new dav_args-structure and initializes it.
   All members are set to reasonable defaults. */
static dav_args *new_args(void) {

    char *user_dir = NULL;
    if (getuid != 0) {
        struct passwd *pw = getpwuid(getuid());
        if (pw == NULL)
            error(EXIT_FAILURE, errno, _("can't read user data base"));
        if (pw->pw_dir == NULL)
            error(EXIT_FAILURE, 0, _("can't read user data base"));
        user_dir = ne_concat(pw->pw_dir, "/.", PACKAGE, NULL);
    }

    dav_args *args = ne_malloc(sizeof(*args));

    args->dav_user = ne_strdup(DAV_USER);
    args->dav_group = ne_strdup(DAV_GROUP);
    args->ignore_home = NULL;

    if (getuid() != 0) {
        args->conf = ne_concat(user_dir, "/", DAV_CONFIG, NULL);
    } else {
        args->conf = NULL;
    }

    args->user = 0;
    args->netdev = 1;
    args->mopts = DAV_MOPTS;
    args->add_mopts = NULL;
    args->kernel_fs = NULL;
    args->buf_size = 0;

    args->uid = getuid();
    args->gid = getgid();
    args->dir_umask = 0;
    args->file_umask = 0;
    args->dir_mode = 0;
    args->file_mode = 0;

    args->scheme = NULL;
    args->host = NULL;
    args->port = 0;
    args->path = NULL;
    args->servercert = NULL;

    if (getuid() != 0) {
        args->secrets = ne_concat(user_dir, "/", DAV_SECRETS, NULL);
    } else {
        args->secrets = NULL;
    }
    args->username = NULL;
    args->password = NULL;
    args->clicert = NULL;
    args->clicert_pw = NULL;

    char *proxy = getenv("http_proxy");
    if (proxy != NULL) {
        split_proxy(&args->p_host, &args->p_port, proxy);
    } else {
        args->p_host = NULL;
        args->p_port = DAV_DEFAULT_PROXY_PORT;
    }
    args->p_user = NULL;
    args->p_passwd = NULL;
    args->useproxy = DAV_USE_PROXY;

    args->askauth = DAV_ASKAUTH;
    args->displayname = DAV_DISPLAYNAME;
    args->locks = DAV_LOCKS;
    args->expect100 = DAV_EXPECT100;
    args->read_timeout = DAV_READ_TIMEOUT;
    args->s_charset = NULL;

    args->sys_cache = ne_strdup(DAV_SYS_CACHE);
    if (getuid() != 0) {
        args->cache_dir = ne_concat(user_dir, "/", DAV_CACHE, NULL);
    } else {
        args->cache_dir = NULL;
    }
    args->backup_dir = ne_strdup(DAV_BACKUP_DIR);
    args->cache_size = DAV_CACHE_SIZE;
    args->table_size = DAV_TABLE_SIZE;
    args->idle_time = DAV_IDLE_TIME;
    args->dir_refresh = DAV_DIR_REFRESH;
    args->file_refresh = DAV_FILE_REFRESH;
    args->gui_optimize = DAV_GUI_OPTIMIZE;
    args->retry = DAV_RETRY;
    args->max_retry = DAV_MAX_RETRY;
    args->lock_timeout = DAV_LOCK_TIMEOUT;
    args->lock_refresh = DAV_LOCK_REFRESH;
    args->lock_owner = NULL;

    if (user_dir != NULL)
        free(user_dir);
    return args;
}


/* Parses line for max. parmc white-space separated parameter tokens and
   returns them in parmv[].
   The '#' character marks the beginning of a comment and the rest of the line
   is ignored.
   Parameters containing one of the characters ' ' (space), '\t' (tab), '\',
   '"' or '#' must be enclosed in double quotes '"' *or* this character has to
   be escaped by preceeding a '\'-character.
   Inside double quotes the '"'-character must be escaped. '\' may be escaped;
   it must be escaped if there is more than on '\'-character in succession.
   Whitespace characters other than ' ' and tab must only occur at the end of
   the line.
   line    : the line to be parsed
   parmc   : the max. number of parameters. It is an error, if more than parmc
             parameters are found
   parmv[] : the parameters found are returned in this array. They are newly
             allocated strings and must be freed by the calling function.
   reurn value : the numer of parameters or -1 if an error occurs. */
static int parse_line(char *line, int parmc, char *parmv[]) {

    enum {
        SPACE,
        SPACE_EXP,
        PARM,
        PARM_ESC,
        PARM_QUO,
        PARM_QUO_ESC,
        ERROR,
        END
    };

    int state = SPACE;
    int parm_no = 0;
    char buf[254];
    char *pos = buf;
    char *end = buf + 253;
    char *p = line;

    while ((state != END) && (state != ERROR)) {
        switch (state) {
        case SPACE:
            if (*p == '\0' || *p == '#') {
                state = END;
            } else if (*p == '\"') {
                state = (parm_no < parmc) ? PARM_QUO : ERROR;
            } else if (*p == '\\') {
                state = (parm_no < parmc) ? PARM_ESC : ERROR;
            } else if (isspace(*p)) {
                ;
            } else if (isgraph(*p)) {
                *pos++ = *p;
                state = (parm_no < parmc) ? PARM : ERROR;
            } else {
                state = ERROR;
            }
            break;
        case SPACE_EXP:
            if (isspace(*p)) {
                state = SPACE;
            } else if (*p == '\0') {
                state = END;
            } else {
                state = ERROR;
            }
            break;
        case PARM:
            if (*p == '#' || *p == '\"') {
                state = ERROR;
            } else if (*p == '\\') {
                state = PARM_ESC;
            } else if (isspace(*p) || *p == '\0') {
                parmv[parm_no++] = ne_strndup(buf, pos - buf);
                pos = buf;
                state = SPACE;
            } else if (isgraph(*p)) {
                *pos++ = *p;
                state = (pos < end) ? PARM : ERROR;
            } else {
                state = ERROR;
            }
            break;
        case PARM_ESC:
            if (*p == '\"' || *p == '\\' || *p == '#' || *p == ' '
                    || *p == '\t') {
                *pos++ = *p;
                state = (pos < end) ? PARM : ERROR;
            } else {
                state = ERROR;
            }
            break;
        case PARM_QUO:
            if (*p == '\\') {
                state = PARM_QUO_ESC;
            } else if (*p == '\"') {
                parmv[parm_no++] = ne_strndup(buf, pos - buf);
                pos = buf;
                state = SPACE_EXP;
            } else if (isgraph(*p) || *p == ' ' || *p == '\t') {
                *pos++ = *p;
                state = (pos < end) ? PARM_QUO : ERROR;
            } else {
                state = ERROR;
            }
            break;
        case PARM_QUO_ESC:
            if (*p == '\"' || *p == '\\') {
                *pos++ = *p;
                state = (pos < end) ? PARM_QUO : ERROR;
            } else if (isgraph(*p) || *p == ' ' || *p == '\t') {
                *pos++ = '\\';
                state = (pos < end) ? PARM_QUO : ERROR;
                if (state == PARM_QUO) {
                    *pos++ = *p;
                    state = (pos < end) ? PARM_QUO : ERROR;
                }
            } else {
                state = ERROR;
            }
            break;
        }
        p++;
    }

    int i;
    if (state == END) {
        for (i = parm_no; i < parmc; i++)
            parmv[i] = NULL;
        return parm_no;
    } else {
        for (i = 0; i < parm_no; i++) {
            free(parmv[i]);
            parmv[i] = NULL;
        }
        return -1;
    }
}


/* Reads the configuration file filename and stores the values in args.
   filename : name of the configuration file.
   system   : boolean value. 1 means it is the system wide configuration
              file. Some parameters are allowed only in the system wide
              configuration file, some only in the user configuration file. */
static void read_config(dav_args *args, const char * filename, int system) {

    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        DBG1("  %s could not be opened.", filename);
        return;
    }
    DBG0("  Reading config from");
    DBG1("    %s.", filename);

    size_t n = 0;
    char *line = NULL;
    int length = getline(&line, &n, file);
    int lineno = 1;
    int applies = 1;

    while (length > 0) {

        int parmc = 2;
        char *parmv[parmc];
        int count;
        count = parse_line(line, parmc, parmv);

        if (count == 1) {

            if (*parmv[0] != '[' || *(parmv[0] + strlen(parmv[0]) - 1) != ']')
                error_at_line(EXIT_FAILURE, 0, filename, lineno,
                              _("malformed line"));
            *(parmv[0] + strlen(parmv[0]) - 1) = '\0';
            applies = (strcmp(parmv[0] + 1, mpoint) == 0);

        } else if (applies && count == 2) {

            if (system && strcmp(parmv[0], "dav_user") == 0) {
                if (args->dav_user != NULL)
                    free(args->dav_user);
                args->dav_user = ne_strdup(parmv[1]); 
            } else if (system && strcmp(parmv[0], "dav_group") == 0) {
                if (args->dav_group != NULL)
                    free(args->dav_group);
                args->dav_group = ne_strdup(parmv[1]); 
            } else if (system && strcmp(parmv[0], "ignore_home") == 0) {
                if (args->ignore_home != NULL)
                    free(args->ignore_home);
                args->ignore_home = ne_strdup(parmv[1]); 
            } else if (strcmp(parmv[0], "kernel_fs") == 0) {
                if (args->kernel_fs != NULL)
                    free(args->kernel_fs);
                args->kernel_fs = ne_strdup(parmv[1]); 
            } else if (strcmp(parmv[0], "buf_size") == 0) {
                args->buf_size = arg_to_int(parmv[1], 10, parmv[0]);
            } else if (strcmp(parmv[0], "servercert") == 0) {
                if (args->servercert != NULL)
                    free(args->servercert);
                args->servercert = ne_strdup(parmv[1]);
            } else if (!system && strcmp(parmv[0], "secrets") == 0) {
                if (args->secrets != NULL)
                    free(args->secrets);
                args->secrets = ne_strdup(parmv[1]); 
            } else if (strcmp(parmv[0], "clientcert") == 0) {
                if (args->clicert != NULL)
                    free(args->clicert);
                args->clicert = ne_strdup(parmv[1]);
            } else if (strcmp(parmv[0], "proxy") == 0) {
                if (args->p_host != NULL)
                    free(args->p_host);
                split_proxy(&args->p_host, &args->p_port, parmv[1]); 
            } else if (strcmp(parmv[0], "use_proxy") == 0) {
                args->useproxy = arg_to_int(parmv[1], 10, parmv[0]);
            } else if (strcmp(parmv[0], "ask_auth") == 0) {
                args->askauth = arg_to_int(parmv[1], 10, parmv[0]);
            } else if (strcmp(parmv[0], "use_displayname") == 0) {
                args->displayname = arg_to_int(parmv[1], 10, parmv[0]);
            } else if (strcmp(parmv[0], "use_locks") == 0) {
                args->locks = arg_to_int(parmv[1], 10, parmv[0]);
            } else if (strcmp(parmv[0], "use_expect100") == 0) {
                args->expect100 = arg_to_int(parmv[1], 10, parmv[0]);
            } else if (strcmp(parmv[0], "read_timeout") == 0) {
                args->read_timeout = arg_to_int(parmv[1], 10, parmv[0]);
            } else if (strcmp(parmv[0], "server_charset") == 0) {
                if (args->s_charset != NULL)
                    free(args->s_charset);
                args->s_charset = ne_strdup(parmv[1]);
            } else if (system && strcmp(parmv[0], "cache_dir") == 0) {
                if (args->sys_cache != NULL)
                    free(args->sys_cache);
                args->sys_cache = ne_strdup(parmv[1]); 
            } else if (!system && strcmp(parmv[0], "cache_dir") == 0) {
                if (args->cache_dir != NULL)
                    free(args->cache_dir);
                args->cache_dir = ne_strdup(parmv[1]); 
            } else if (strcmp(parmv[0], "backup_dir") == 0) {
                if (args->backup_dir != NULL)
                    free(args->backup_dir);
                args->backup_dir = ne_strdup(parmv[1]); 
            } else if (strcmp(parmv[0], "cache_size") == 0) {
                args->cache_size = arg_to_int(parmv[1], 10, parmv[0]); 
            } else if (strcmp(parmv[0], "table_size") == 0) {
                args->table_size = arg_to_int(parmv[1], 10, parmv[0]); 
            } else if (strcmp(parmv[0], "idle_time") == 0) {
                args->idle_time = arg_to_int(parmv[1], 10, parmv[0]); 
            } else if (strcmp(parmv[0], "dir_refresh") == 0) {
                args->dir_refresh = arg_to_int(parmv[1], 10, parmv[0]); 
            } else if (strcmp(parmv[0], "file_refresh") == 0) {
                args->file_refresh = arg_to_int(parmv[1], 10, parmv[0]); 
            } else if (strcmp(parmv[0], "gui_optimize") == 0) {
                args->gui_optimize = arg_to_int(parmv[1], 10, parmv[0]); 
            } else if (strcmp(parmv[0], "retry") == 0) {
                args->retry = arg_to_int(parmv[1], 10, parmv[0]); 
            } else if (strcmp(parmv[0], "max_retry") == 0) {
                args->max_retry = arg_to_int(parmv[1], 10, parmv[0]);
            } else if (strcmp(parmv[0], "lock_timeout") == 0) {
                args->lock_timeout = arg_to_int(parmv[1], 10, parmv[0]);
            } else if (strcmp(parmv[0], "lock_refresh") == 0) {
                args->lock_refresh = arg_to_int(parmv[1], 10, parmv[0]);
            } else if (strcmp(parmv[0], "lock_owner") == 0) {
                if (args->lock_owner != NULL)
                    free(args->lock_owner);
                args->lock_owner = ne_strdup(parmv[1]);
            } else {
                error_at_line(EXIT_FAILURE, 0, filename, lineno,
                              _("unknown option"));
            }

        } else if (count < 0 || count > 2) {

            error_at_line(EXIT_FAILURE, 0, filename, lineno,
                          _("malformed line"));
        }

        for (parmc = 0; parmc < count; parmc++)
            free(parmv[parmc]);
        length = getline(&line, &n, file);
        lineno++;
    }

    if (line != NULL)
        free(line);
    fclose(file);
}


/* Searches the file filename for credentials for server url and for the proxy
   args->p_host and stores them in args. */
static void read_secrets(dav_args *args, const char *filename) {

    struct stat st;
    if (stat(filename, &st) < 0) {
        DBG1("  %s could not be opened.", filename);
        return;
    }
    if (st.st_uid != geteuid())
        error(EXIT_FAILURE, 0, _("file %s has wrong owner"), filename);
    if ((st.st_mode &
          (S_IXUSR | S_IRWXG | S_IRWXO | S_ISUID | S_ISGID | S_ISVTX)) != 0)
        error(EXIT_FAILURE, 0, _("file %s has wrong permissions"), filename);

    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        DBG1("  %s could not be opened.", filename);
        return;
    }
    DBG0("  Reading secrets from");
    DBG1("    %s.", filename);

    size_t n = 0;
    char *line = NULL;
    int length = getline(&line, &n, file);
    int lineno = 1;

    while (length > 0) {
        int parmc = 3;
        char *parmv[parmc];
        int count;
        count = parse_line(line, parmc, parmv);
        if (count != 0 && count != 3 && count != 2)
            error_at_line(EXIT_FAILURE, 0, filename, lineno,
                          _("malformed line"));

        if (count == 2 || count == 3) {
            if (args->p_host != NULL && strcmp(parmv[0], args->p_host) == 0) {
                if (args->p_user != NULL) {
                    memset(args->p_user, '\0', strlen(args->p_user));
                    free(args->p_user);
                }
                if (args->p_passwd != NULL) {
                    memset(args->p_passwd, '\0', strlen(args->p_passwd));
                    free(args->p_passwd);
                }
                args->p_user = ne_strdup(parmv[1]);
                if (count == 3)
                    args->p_passwd = ne_strdup(parmv[2]);
            } else if (url != NULL && strcmp(parmv[0], url) == 0) {
                if (args->username != NULL) {
                    memset(args->username, '\0', strlen(args->username));
                    free(args->username);
                }
                if (args->password != NULL) {
                    memset(args->password, '\0', strlen(args->password));
                    free(args->password);
                }
                args->username = ne_strdup(parmv[1]);
                if (count == 3)
                    args->password = ne_strdup(parmv[2]);
            } else if (args->clicert != NULL
                    && strcmp(parmv[0], args->clicert) == 0) {
                if (count != 2)
                    error_at_line(EXIT_FAILURE, 0, filename, lineno,
                                  _("malformed line"));
                if (args->clicert_pw != NULL) {
                    memset(args->clicert_pw, '\0', strlen(args->clicert_pw));
                    free(args->clicert_pw);
                }
                args->clicert_pw = ne_strdup(parmv[1]);
            }
        }

        for (parmc = 0; parmc < count; parmc++) {
            memset(parmv[parmc], '\0', strlen(parmv[parmc]));
            free(parmv[parmc]);
        }
        memset(line, '\0', strlen(line));
        length = getline(&line, &n, file);
        lineno++;
    }

    if (line != NULL) {
        memset(line, '\0', strlen(line));
        free(line);
    }
    fclose(file);
}


/* Splits arg into hostname and port if there is a colon in arg. If there is no
   colon, arg is taken als hostname, and port is set to DAV_DEFAULT_PROXY_PORT.
   The string host will be newly allacoated. The calling function is
   responsible to free it.
   host  : A pointer to a string to return the hostname.
   port  : A pointer to an integer to return the port number.
   arg   : the string to be split. */
static void split_proxy(char **host, int *port, const char *arg) {

    char *ps = strchr(arg, ':');
    if (ps == NULL) {
        *host = ne_strdup(arg);
        *port = DAV_DEFAULT_PROXY_PORT;
    } else {
        *host = ne_strndup(arg, strlen(arg) - strlen(ps));
        ps++;
        *port = arg_to_int(ps, 10, "proxy:port");
    }
}


/* Prints version und help text. */
static void usage(void) {

    printf(_("Usage:\n"
             "    %s -V,--version   : print version string\n"
             "    %s -h,--help      : print this message\n\n"),
           PROGRAM_NAME, PROGRAM_NAME);
    printf(_("To mount a WebDAV-resource don't call %s directly, but use\n"
             "`mount' instead.\n"), PROGRAM_NAME);
    printf(_("    mount <mountpoint>  : or\n"
             "    mount <server-url>  : mount the WebDAV-resource as specified in\n"
             "                          /etc/fstab.\n"));
    printf(_("    mount -t davfs <server-url> <mountpoint> [-o options]\n"
             "                        : mount the WebDAV-resource <server-url>\n"
             "                          on mountpoint <mountpoint>. Only root\n"
             "                          is allowed to do this. options is a\n"
             "                          comma separated list of options.\n\n"));
    printf(_("Recognised options:\n"
             "    conf=        : absolute path of user configuration file\n"
             "    uid=         : owner of the filesystem (username or numeric id)\n"
             "    gid=         : group of the filesystem (group name or numeric id)\n"
             "    file_mode=   : default file mode (octal)\n"
             "    dir_mode=    : default directory mode (octal)\n"));
    printf(_("    ro           : mount read-only\n"
             "    rw           : mount read-write\n"
             "    [no]exec     : (don't) allow execution of binaries\n"
             "    [no]suid     : (don't) allow suid and sgid bits to take effect\n"
             "    [no]_netdev  : (no) network connection needed\n"));
}

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