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xrdp/sesman/sesman.c

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/**
* xrdp: A Remote Desktop Protocol server.
*
* Copyright (C) Jay Sorg 2004-2015
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
*
* @file sesman.c
* @brief Main program file
* @author Jay Sorg
*
*/
#if defined(HAVE_CONFIG_H)
#include <config_ac.h>
#endif
#include <stdarg.h>
#include "arch.h"
#include "sesman.h"
#include "auth.h"
#include "config.h"
#include "lock_uds.h"
#include "os_calls.h"
#include "scp.h"
#include "scp_process.h"
#include "sig.h"
#include "string_calls.h"
#include "trans.h"
#include "xrdp_configure_options.h"
/**
* Maximum number of short-lived connections to sesman
*
* At the moment, all connections to sesman are short-lived. This may change
* in the future
*/
#define MAX_SHORT_LIVED_CONNECTIONS 16
/**
* Define the mode of operation of the program
*/
enum sesman_mode
{
SSM_NORMAL = 0,
SSM_KILL_DAEMON,
SSM_RELOAD_DAEMON
};
struct sesman_startup_params
{
const char *sesman_ini;
enum sesman_mode mode;
int no_daemon;
int help;
int version;
int dump_config;
};
struct config_sesman *g_cfg;
unsigned char g_fixedkey[8] = { 23, 82, 107, 6, 35, 78, 88, 7 };
static tintptr g_term_event = 0;
static tintptr g_sigchld_event = 0;
static tintptr g_reload_event = 0;
static struct trans *g_list_trans;
/* Variables used to lock g_list_trans */
static struct lock_uds *g_list_trans_lock;
static struct list *g_con_list = NULL;
static int g_pid;
/*****************************************************************************/
/**
* @brief looks for a case-insensitive match of a string in a list
* @param candidate String to match
* @param ... NULL-terminated list of strings to compare the candidate with
* @return !=0 if the candidate is found in the list
*/
static int nocase_matches(const char *candidate, ...)
{
va_list vl;
const char *member;
int result = 0;
va_start(vl, candidate);
while ((member = va_arg(vl, const char *)) != NULL)
{
if (g_strcasecmp(candidate, member) == 0)
{
result = 1;
break;
}
}
va_end(vl);
return result;
}
/**
* Allocates a sesman_con struct
*
* @param trans Pointer to newly-allocated transport
* @return struct sesman_con pointer
*/
static struct sesman_con *
alloc_connection(struct trans *t)
{
struct sesman_con *result;
if ((result = g_new0(struct sesman_con, 1)) != NULL)
{
g_snprintf(result->peername, sizeof(result->peername), "%s", "unknown");
result->t = t;
result->auth_retry_count = g_cfg->sec.login_retry;
}
return result;
}
/**
* Deletes a sesman_con struct, freeing resources
*
* After this call, the passed-in pointer is invalid and must not be
* referenced.
*
* Any auth_info struct found in the sesman_con is also deallocated.
*
* @param sc struct to de-allocate
*/
static void
delete_connection(struct sesman_con *sc)
{
if (sc != NULL)
{
trans_delete(sc->t);
if (sc->auth_info != NULL)
{
auth_end(sc->auth_info);
}
g_free(sc->username);
g_free(sc->ip_addr);
g_free(sc);
}
}
/*****************************************************************************/
int
sesman_set_connection_peername(struct sesman_con *sc, const char *name)
{
int rv = 1;
if (sc != NULL && name != NULL)
{
g_snprintf(sc->peername, sizeof(sc->peername), "%s", name);
rv = 0;
}
return rv;
}
/*****************************************************************************/
/**
*
* @brief Command line argument parser
* @param[in] argc number of command line arguments
* @param[in] argv pointer array of commandline arguments
* @param[out] sesman_startup_params Returned startup parameters
* @return 0 on success, n on nth argument is unknown
*
*/
static int
sesman_process_params(int argc, char **argv,
struct sesman_startup_params *startup_params)
{
int index;
const char *option;
const char *value;
startup_params->mode = SSM_NORMAL;
index = 1;
while (index < argc)
{
option = argv[index];
if (index + 1 < argc)
{
value = argv[index + 1];
}
else
{
value = "";
}
if (nocase_matches(option, "-help", "--help", "-h", NULL))
{
startup_params->help = 1;
}
else if (nocase_matches(option, "-kill", "--kill", "-k", NULL))
{
startup_params->mode = SSM_KILL_DAEMON;
}
else if (nocase_matches(option, "-reload", "--reload", "-r", NULL))
{
startup_params->mode = SSM_RELOAD_DAEMON;
}
else if (nocase_matches(option, "-nodaemon", "--nodaemon", "-n",
"-nd", "--nd", "-ns", "--ns", NULL))
{
startup_params->no_daemon = 1;
}
else if (nocase_matches(option, "-v", "--version", NULL))
{
startup_params->version = 1;
}
else if (nocase_matches(option, "--dump-config", NULL))
{
startup_params->dump_config = 1;
}
else if (nocase_matches(option, "-c", "--config", NULL))
{
index++;
startup_params->sesman_ini = value;
}
else /* unknown option */
{
return index;
}
index++;
}
return 0;
}
/******************************************************************************/
static int
create_sesman_runtime_dir(void)
{
int rv = -1;
/* Make sure if we create the directory, there's no gap where it
* may have the wrong permissions */
int entry_umask = g_umask_hex(0x755);
if (!g_directory_exist(SESMAN_RUNTIME_PATH) &&
!g_create_dir(SESMAN_RUNTIME_PATH))
{
LOG(LOG_LEVEL_ERROR,
"Can't create runtime directory '"
SESMAN_RUNTIME_PATH "' [%s]", g_get_strerror());
}
else if (g_chown(SESMAN_RUNTIME_PATH, g_getuid(), g_getuid()) != 0)
{
LOG(LOG_LEVEL_ERROR,
"Can't set ownership of sesman runtime directory [%s]",
g_get_strerror());
}
else if (g_chmod_hex(SESMAN_RUNTIME_PATH, 0x755) != 0)
{
/* This might seem redundant, but there's a chance the
* directory already exists */
LOG(LOG_LEVEL_ERROR,
"Can't set permissions of sesman runtime directory [%s]",
g_get_strerror());
}
else
{
rv = 0;
}
g_umask_hex(entry_umask);
return rv;
}
/******************************************************************************/
static int sesman_listen_test(struct config_sesman *cfg)
{
int status = sesman_create_listening_transport(cfg);
sesman_delete_listening_transport();
return status;
}
/******************************************************************************/
int
sesman_close_all(unsigned int flags)
{
int index;
struct sesman_con *sc;
LOG_DEVEL(LOG_LEVEL_TRACE, "sesman_close_all:");
sesman_delete_listening_transport();
for (index = 0; index < g_con_list->count; index++)
{
sc = (struct sesman_con *) list_get_item(g_con_list, index);
if (sc != NULL && (flags & SCA_CLOSE_AUTH_INFO) == 0)
{
// Prevent delete_connection() closing the auth_info down
sc->auth_info = NULL;
}
delete_connection(sc);
}
return 0;
}
/******************************************************************************/
void
sesman_delete_wait_objects(void)
{
g_delete_wait_obj(g_reload_event);
g_delete_wait_obj(g_sigchld_event);
g_delete_wait_obj(g_term_event);
}
/******************************************************************************/
static int
sesman_data_in(struct trans *self)
{
int rv;
int available;
rv = scp_msg_in_check_available(self, &available);
if (rv == 0 && available)
{
struct sesman_con *sc = (struct sesman_con *)self->callback_data;
if ((rv = scp_process(sc)) != 0)
{
LOG(LOG_LEVEL_ERROR, "sesman_data_in: scp_process_msg failed");
}
scp_msg_in_reset(self);
}
return rv;
}
/******************************************************************************/
static int
sesman_listen_conn_in(struct trans *self, struct trans *new_self)
{
struct sesman_con *sc;
if (g_con_list->count >= MAX_SHORT_LIVED_CONNECTIONS)
{
LOG(LOG_LEVEL_ERROR, "sesman_data_in: error, too many "
"connections, rejecting");
trans_delete(new_self);
}
else if ((sc = alloc_connection(new_self)) == NULL ||
scp_init_trans(new_self) != 0)
{
LOG(LOG_LEVEL_ERROR, "sesman_data_in: No memory to allocate "
"new connection");
delete_connection(sc);
}
else
{
new_self->callback_data = (void *)sc;
new_self->trans_data_in = sesman_data_in;
list_add_item(g_con_list, (intptr_t) sc);
}
return 0;
}
/******************************************************************************/
/**
* Informs the main loop a termination signal has been received
*/
static void
set_term_event(int sig)
{
/* Don't try to use a wait obj in a child process */
if (g_getpid() == g_pid)
{
g_set_wait_obj(g_term_event);
}
}
/******************************************************************************/
/**
* Informs the main loop a SIGCHLD has been received
*/
static void
set_sigchld_event(int sig)
{
/* Don't try to use a wait obj in a child process */
if (g_getpid() == g_pid)
{
g_set_wait_obj(g_sigchld_event);
}
}
/******************************************************************************/
/**
* Informs the main loop a SIGHUP has been received
*/
static void
set_reload_event(int sig)
{
/* Don't try to use a wait obj in a child process */
if (g_getpid() == g_pid)
{
g_set_wait_obj(g_reload_event);
}
}
/******************************************************************************/
void
sesman_delete_listening_transport(void)
{
if (g_getpid() == g_pid)
{
trans_delete(g_list_trans);
}
else
{
trans_delete_from_child(g_list_trans);
}
g_list_trans = NULL;
unlock_uds(g_list_trans_lock);
g_list_trans_lock = NULL;
}
/******************************************************************************/
int
sesman_create_listening_transport(const struct config_sesman *cfg)
{
int rv = 1;
g_list_trans = trans_create(TRANS_MODE_UNIX, 8192, 8192);
if (g_list_trans == NULL)
{
LOG(LOG_LEVEL_ERROR, "%s: trans_create failed", __func__);
}
else if ((g_list_trans_lock = lock_uds(cfg->listen_port)) != NULL)
{
/* Make sure the file is always created with the correct
* permissions, if it's not there */
int entry_umask = g_umask_hex(0x666);
LOG_DEVEL(LOG_LEVEL_DEBUG, "%s: port %s", __func__, cfg->listen_port);
rv = trans_listen_address(g_list_trans, cfg->listen_port, NULL);
if (rv != 0)
{
LOG(LOG_LEVEL_ERROR, "%s: trans_listen_address failed", __func__);
}
else if (g_chown(cfg->listen_port, g_getuid(), g_getuid()) != 0)
{
LOG(LOG_LEVEL_ERROR,
"Can't set ownership of '%s' [%s]",
cfg->listen_port, g_get_strerror());
}
else if ((rv = g_chmod_hex(cfg->listen_port, 0x666)) != 0)
{
LOG(LOG_LEVEL_ERROR, "%s: Can't set permissions on '%s' [%s]",
__func__, cfg->listen_port, g_get_strerror());
}
else
{
g_list_trans->trans_conn_in = sesman_listen_conn_in;
}
g_umask_hex(entry_umask);
}
if (rv != 0)
{
sesman_delete_listening_transport();
}
return rv;
}
/******************************************************************************/
/**
*
* @brief Starts sesman main loop
*
*/
static int
sesman_main_loop(void)
{
int error;
int robjs_count;
int wobjs_count;
int timeout;
int index;
intptr_t robjs[32];
intptr_t wobjs[32];
struct sesman_con *scon;
g_con_list = list_create();
if (g_con_list == NULL)
{
LOG(LOG_LEVEL_ERROR, "sesman_main_loop: list_create failed");
return 1;
}
if (sesman_create_listening_transport(g_cfg) != 0)
{
LOG(LOG_LEVEL_ERROR,
"sesman_main_loop: sesman_create_listening_transport failed");
list_delete(g_con_list);
return 1;
}
LOG(LOG_LEVEL_INFO, "Sesman now listening on %s", g_cfg->listen_port);
error = 0;
while (!error)
{
timeout = -1;
robjs_count = 0;
robjs[robjs_count++] = g_term_event;
robjs[robjs_count++] = g_sigchld_event;
robjs[robjs_count++] = g_reload_event;
wobjs_count = 0;
for (index = 0; index < g_con_list->count; index++)
{
scon = (struct sesman_con *)list_get_item(g_con_list, index);
if (scon != NULL)
{
error = trans_get_wait_objs_rw(scon->t,
robjs, &robjs_count,
wobjs, &wobjs_count, &timeout);
if (error != 0)
{
LOG(LOG_LEVEL_ERROR, "sesman_main_loop: "
"trans_get_wait_objs_rw failed");
break;
}
}
}
if (error != 0)
{
break;
}
if (g_list_trans != NULL)
{
/* g_list_trans might be NULL on a reconfigure if sesman
* is unable to listen again */
error = trans_get_wait_objs_rw(g_list_trans, robjs, &robjs_count,
wobjs, &wobjs_count, &timeout);
if (error != 0)
{
LOG(LOG_LEVEL_ERROR, "sesman_main_loop: "
"trans_get_wait_objs_rw failed");
break;
}
}
if (g_obj_wait(robjs, robjs_count, wobjs, wobjs_count, timeout) != 0)
{
/* should not get here */
LOG(LOG_LEVEL_WARNING, "sesman_main_loop: "
"Unexpected error from g_obj_wait()");
g_sleep(100);
}
if (g_is_wait_obj_set(g_term_event)) /* term */
{
LOG(LOG_LEVEL_INFO, "sesman_main_loop: "
"sesman asked to terminate");
break;
}
if (g_is_wait_obj_set(g_sigchld_event)) /* A child has exited */
{
g_reset_wait_obj(g_sigchld_event);
sig_sesman_session_end();
}
if (g_is_wait_obj_set(g_reload_event)) /* We're asked to reload */
{
g_reset_wait_obj(g_reload_event);
sig_sesman_reload_cfg();
}
index = 0;
while (index < g_con_list->count)
{
int remove_con = 0;
scon = (struct sesman_con *)list_get_item(g_con_list, index);
if (trans_check_wait_objs(scon->t) != 0)
{
LOG(LOG_LEVEL_ERROR, "sesman_main_loop: "
"trans_check_wait_objs failed, removing trans");
remove_con = 1;
}
else if (scon->close_requested)
{
remove_con = 1;
}
if (remove_con)
{
delete_connection(scon);
list_remove_item(g_con_list, index);
}
else
{
++index;
}
}
if (g_list_trans != NULL)
{
error = trans_check_wait_objs(g_list_trans);
if (error != 0)
{
LOG(LOG_LEVEL_ERROR, "sesman_main_loop: "
"trans_check_wait_objs failed");
break;
}
}
}
sesman_close_all(SCA_CLOSE_AUTH_INFO);
list_delete(g_con_list);
return 0;
}
/*****************************************************************************/
static void
print_version(void)
{
g_writeln("xrdp-sesman %s", PACKAGE_VERSION);
g_writeln(" The xrdp session manager");
g_writeln(" Copyright (C) 2004-2020 Jay Sorg, "
"Neutrino Labs, and all contributors.");
g_writeln(" See https://github.com/neutrinolabs/xrdp for more information.");
g_writeln("%s", "");
#if defined(XRDP_CONFIGURE_OPTIONS)
g_writeln(" Configure options:");
g_writeln("%s", XRDP_CONFIGURE_OPTIONS);
#endif
}
/******************************************************************************/
static void
print_help(void)
{
g_printf("Usage: xrdp-sesman [options]\n");
g_printf(" -k, --kill shut down xrdp-sesman\n");
g_printf(" -r, --reload reload xrdp-sesman\n");
g_printf(" -h, --help show help\n");
g_printf(" -v, --version show version\n");
g_printf(" -n, --nodaemon don't fork into background\n");
g_printf(" -c, --config specify new path to sesman.ini\n");
g_printf(" --dump-config display config on stdout on startup\n");
g_deinit();
}
/******************************************************************************/
/**
* Reads the PID file
*/
static int
read_pid_file(const char *pid_file, int *pid)
{
int rv = 1;
int fd;
/* check if sesman is running */
if (!g_file_exist(pid_file))
{
g_printf("sesman is not running (pid file not found - %s)\n", pid_file);
}
else if ((fd = g_file_open(pid_file)) < 0)
{
g_printf("error opening pid file[%s]: %s\n", pid_file, g_get_strerror());
}
else
{
char pid_s[32] = {0};
int error = g_file_read(fd, pid_s, sizeof(pid_s) - 1);
g_file_close(fd);
if (error < 0)
{
g_printf("error reading pid file: %s\n", g_get_strerror());
}
else
{
*pid = g_atoi(pid_s);
rv = 0;
}
}
return rv;
}
/******************************************************************************/
int
main(int argc, char **argv)
{
int error;
enum logReturns log_error;
char text[256];
char pid_file[256];
char default_sesman_ini[256];
struct sesman_startup_params startup_params = {0};
int errored_argc;
int daemon;
g_init("xrdp-sesman");
g_snprintf(pid_file, 255, "%s/xrdp-sesman.pid", XRDP_PID_PATH);
g_snprintf(default_sesman_ini, 255, "%s/sesman.ini", XRDP_CFG_PATH);
startup_params.sesman_ini = default_sesman_ini;
errored_argc = sesman_process_params(argc, argv, &startup_params);
if (errored_argc > 0)
{
print_version();
g_writeln("%s", "");
print_help();
g_writeln("%s", "");
g_writeln("Unknown option: %s", argv[errored_argc]);
g_deinit();
g_exit(1);
}
if (startup_params.help)
{
print_help();
g_exit(0);
}
if (startup_params.version)
{
print_version();
g_exit(0);
}
if (startup_params.mode == SSM_KILL_DAEMON)
{
int pid;
int error = 1;
if (read_pid_file(pid_file, &pid) == 0)
{
if (g_sigterm(pid) != 0)
{
g_printf("error killing sesman: %s\n", g_get_strerror());
}
else
{
/* File is no longer required */
g_file_delete(pid_file);
error = 0;
}
}
g_deinit();
g_exit(error);
}
if (startup_params.mode == SSM_RELOAD_DAEMON)
{
int pid;
int error = 1;
if (read_pid_file(pid_file, &pid) == 0)
{
if (g_sighup(pid) != 0)
{
g_printf("error reloading sesman: %s\n", g_get_strerror());
}
else
{
error = 0;
}
}
g_deinit();
g_exit(error);
}
if (g_file_exist(pid_file))
{
g_printf("xrdp-sesman is already running.\n");
g_printf("if it's not running, try removing ");
g_printf("%s", pid_file);
g_printf("\n");
g_deinit();
g_exit(1);
}
/* starting logging subsystem */
if (!g_file_exist(startup_params.sesman_ini))
{
g_printf("Config file %s does not exist\n", startup_params.sesman_ini);
g_deinit();
g_exit(1);
}
log_error = log_start(
startup_params.sesman_ini, "xrdp-sesman",
(startup_params.dump_config) ? LOG_START_DUMP_CONFIG : 0);
if (log_error != LOG_STARTUP_OK)
{
switch (log_error)
{
case LOG_ERROR_MALLOC:
g_writeln("error on malloc. cannot start logging. quitting.");
break;
case LOG_ERROR_FILE_OPEN:
g_writeln("error opening log file [%s]. quitting.",
getLogFile(text, 255));
break;
default:
// Assume sufficient messages have already been generated
break;
}
g_deinit();
g_exit(1);
}
/* reading config */
if ((g_cfg = config_read(startup_params.sesman_ini)) == NULL)
{
LOG(LOG_LEVEL_ALWAYS, "error reading config %s: %s",
startup_params.sesman_ini, g_get_strerror());
log_end();
g_deinit();
g_exit(1);
}
if (startup_params.dump_config)
{
config_dump(g_cfg);
}
LOG(LOG_LEVEL_TRACE, "config loaded in %s at %s:%d", __func__, __FILE__, __LINE__);
LOG(LOG_LEVEL_TRACE, " sesman_ini = %s", g_cfg->sesman_ini);
LOG(LOG_LEVEL_TRACE, " listen_port = %s", g_cfg->listen_port);
LOG(LOG_LEVEL_TRACE, " enable_user_wm = %d", g_cfg->enable_user_wm);
LOG(LOG_LEVEL_TRACE, " default_wm = %s", g_cfg->default_wm);
LOG(LOG_LEVEL_TRACE, " user_wm = %s", g_cfg->user_wm);
LOG(LOG_LEVEL_TRACE, " reconnect_sh = %s", g_cfg->reconnect_sh);
LOG(LOG_LEVEL_TRACE, " auth_file_path = %s", g_cfg->auth_file_path);
daemon = !startup_params.no_daemon;
if (daemon)
{
/* not to spit on the console, shut up stdout/stderr before anything's logged */
g_file_close(0);
g_file_close(1);
g_file_close(2);
if (g_file_open("/dev/null") < 0)
{
}
if (g_file_open("/dev/null") < 0)
{
}
if (g_file_open("/dev/null") < 0)
{
}
}
/* Create the runtime directory before we try to listen (or
* test-listen), so there's somewhere for the default socket to live */
if (create_sesman_runtime_dir() != 0)
{
config_free(g_cfg);
log_end();
g_deinit();
g_exit(1);
}
if (daemon)
{
/* start of daemonizing code */
if (sesman_listen_test(g_cfg) != 0)
{
LOG(LOG_LEVEL_ERROR, "Failed to start xrdp-sesman daemon, "
"possibly address already in use.");
config_free(g_cfg);
log_end();
g_deinit();
g_exit(1);
}
if (0 != g_fork())
{
config_free(g_cfg);
log_end();
g_deinit();
g_exit(0);
}
}
/* Now we've forked (if necessary), we can get the program PID */
g_pid = g_getpid();
/* signal handling */
g_snprintf(text, 255, "xrdp_sesman_%8.8x_main_term", g_pid);
g_term_event = g_create_wait_obj(text);
g_snprintf(text, 255, "xrdp_sesman_%8.8x_sigchld", g_pid);
g_sigchld_event = g_create_wait_obj(text);
g_snprintf(text, 255, "xrdp_sesman_%8.8x_reload", g_pid);
g_reload_event = g_create_wait_obj(text);
g_signal_hang_up(set_reload_event); /* SIGHUP */
g_signal_user_interrupt(set_term_event); /* SIGINT */
g_signal_terminate(set_term_event); /* SIGTERM */
g_signal_child_stop(set_sigchld_event); /* SIGCHLD */
if (daemon)
{
/* writing pid file */
char pid_s[32];
int fd = g_file_open(pid_file);
if (-1 == fd)
{
LOG(LOG_LEVEL_ERROR,
"error opening pid file[%s]: %s",
pid_file, g_get_strerror());
log_end();
config_free(g_cfg);
g_deinit();
g_exit(1);
}
g_sprintf(pid_s, "%d", g_pid);
g_file_write(fd, pid_s, g_strlen(pid_s));
g_file_close(fd);
}
/* start program main loop */
LOG(LOG_LEVEL_INFO,
"starting xrdp-sesman with pid %d", g_pid);
/* make sure the socket directory exists */
g_mk_socket_path("xrdp-sesman");
/* make sure the /tmp/.X11-unix directory exists */
if (!g_directory_exist("/tmp/.X11-unix"))
{
if (!g_create_dir("/tmp/.X11-unix"))
{
LOG(LOG_LEVEL_ERROR,
"sesman.c: error creating dir /tmp/.X11-unix");
}
g_chmod_hex("/tmp/.X11-unix", 0x1777);
}
error = sesman_main_loop();
/* clean up PID file on exit */
if (daemon)
{
g_file_delete(pid_file);
}
sesman_delete_wait_objects();
if (!daemon)
{
log_end();
}
config_free(g_cfg);
g_deinit();
g_exit(error);
return 0;
}
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