/* backend.c - twoftpd back-end startup code

* Copyright (C) 2008 Bruce Guenter <bruce@untroubled.org>

*

* This program 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.

*

* This program 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 this program; if not, write to the Free Software

* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

*/

#include <sys/types.h>

#include <grp.h>

#include <limits.h>

#include <stdlib.h>

#include <string.h>

#include <bglibs/systime.h>

#include <unistd.h>

#include <bglibs/sysdeps.h>

#include <bglibs/path.h>

#include "twoftpd.h"

#include "backend.h"

uid_t uid;

gid_t gid;

const char* home;

const char* user;

unsigned user_len;

const char* group;

unsigned group_len;

time_t now;

int lockhome;

int nodotfiles;

int bind_port_fd = -1;

unsigned connect_timeout = 0;

int handle_pass(void)

{

return respond(230, 1, "Access has already been granted.");

}

static int load_tables(void)

{

/* Load some initial values that cannot be loaded once the chroot is done. */

/* A call to localtime should load and cache the timezone setting. */

now = time(0);

localtime(&now);

return 1;

}

static int parse_gids(const char* gids)

{

gid_t groups[NGROUPS_MAX];

int count;

const char* ptr;

ptr = gids;

count = 0;

while (*ptr != 0 && count < NGROUPS_MAX) {

groups[count] = strtou(ptr, &ptr);

if (*ptr != 0 && *ptr != ',') return 0;

while (*ptr == ',') ++ptr;

++count;

}

if (setgroups(count, groups) == -1) return 0;

return 1;

}

#define FAIL(MSG) do{ respond(421, 1, MSG); return 0; }while(0)

int startup(int argc, char* argv[])

{

const char* tmp;

const char* end;

const char* cwdstr;

char* ptr;

unsigned long session_timeout;

unsigned startup_code;

if ((tmp = getenv("TCPLOCALIP")) == 0) FAIL("Missing $TCPLOCALIP.");

if (!parse_localip(tmp)) FAIL("Could not parse $TCPLOCALIP.");

if ((tmp = getenv("TCPREMOTEIP")) == 0) FAIL("Missing $TCPREMOTEIP.");

if (!parse_remoteip(tmp)) FAIL("Could not parse $TCPREMOTEIP.");

if ((tmp = getenv("UID")) == 0) FAIL("Missing $UID.");

if (!(uid = strtou(tmp, &end)) || *end) FAIL("Invalid $UID.");

if ((tmp = getenv("GID")) == 0) FAIL("Missing $GID.");

if (!(gid = strtou(tmp, &end)) || *end) FAIL("Invalid $GID.");

if ((home = getenv("HOME")) == 0) FAIL("Missing $HOME.");

if ((tmp = getenv("GIDS")) != 0 && !parse_gids(tmp))

FAIL("Could not parse or set supplementary group IDs.");

/* Strip off trailing slashes in $HOME */

ptr = (char*)home + strlen(home)-1;

while (ptr > home && *ptr == '/') *ptr-- = 0;

if ((user = getenv("USER")) == 0) FAIL("Missing $USER.");

if ((group = getenv("GROUP")) == 0) group = "mygroup";

if (chdir(home)) FAIL("Could not chdir to $HOME.");

if (!load_tables()) FAIL("Loading startup tables failed.");

if (getenv("CHROOT") != 0) {

cwdstr = "/";

if (chroot(".")) FAIL("Could not chroot.");

}

else if (getenv("SOFTCHROOT") != 0) {

cwdstr = "/";

}

else {

cwdstr = home;

if (chdir("/")) FAIL("Could not chdir to '/'.");

}

if (!str_copys(&cwd, cwdstr)) FAIL("Could not set CWD string");

if (setgid(gid)) FAIL("Could not set GID.");

if (setuid(uid)) FAIL("Could not set UID.");

if ((user_len = strlen(user)) > MAX_NAME_LEN) {

user_len = MAX_NAME_LEN;

((char*)user)[MAX_NAME_LEN] = 0;

}

if ((group_len = strlen(group)) > MAX_NAME_LEN) {

group_len = MAX_NAME_LEN;

((char*)group)[MAX_NAME_LEN] = 0;

}

lockhome = (getenv("LOCKHOME") != 0);

nodotfiles = (getenv("NODOTFILES") != 0);

list_options = (nodotfiles ? 0 : PATH_MATCH_DOTFILES);

session_timeout = 0;

if ((tmp = getenv("SESSION_TIMEOUT")) != 0)

session_timeout = strtou(tmp, &tmp);

alarm(session_timeout);

connect_timeout = timeout;

if ((tmp = getenv("CONNECT_TIMEOUT")) != 0)

connect_timeout = strtou(tmp, &tmp);

if ((tmp = getenv("TWOFTPD_BIND_PORT_FD")) != 0) {

if ((bind_port_fd = strtou(tmp, &end)) == 0 || *end != 0)

FAIL("Invalid $TWOFTPD_BIND_PORT_FD");

}

else

bind_port_fd = -1;

startup_code = (getenv("AUTHENTICATED") != 0) ? 230 : 220;

if ((tmp = getenv("BANNER")) != 0) show_banner(startup_code, tmp);

message_file = getenv("MESSAGEFILE");

show_message_file(startup_code);

return respond(startup_code, 1, "Ready to transfer files.");

(void)argc;

(void)argv;

}