/* Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

-- Copyright (C) 2009 Tobias Markmann

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

*/

/*

* pposix.c

* POSIX support functions for Lua

*/

#define MODULE_VERSION "0.4.0"

#if defined(__linux__)

#ifndef _GNU_SOURCE

#define _GNU_SOURCE

#endif

#else

#ifndef _DEFAULT_SOURCE

#define _DEFAULT_SOURCE

#endif

#endif

#if defined(__APPLE__)

#ifndef _DARWIN_C_SOURCE

#define _DARWIN_C_SOURCE

#endif

#endif

#if ! defined(__FreeBSD__)

#ifndef _POSIX_C_SOURCE

#define _POSIX_C_SOURCE 200809L

#endif

#endif

#include <stdlib.h>

#include <math.h>

#include <unistd.h>

#include <libgen.h>

#include <sys/resource.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <sys/utsname.h>

#include <fcntl.h>

#include <syslog.h>

#include <pwd.h>

#include <grp.h>

#include <string.h>

#include <errno.h>

#include "lua.h"

#include "lualib.h"

#include "lauxlib.h"

#if (LUA_VERSION_NUM < 503)

#define lua_isinteger(L, n) lua_isnumber(L, n)

#endif

#if (LUA_VERSION_NUM < 504)

#define luaL_pushfail lua_pushnil

#endif

#include <fcntl.h>

#if defined(__linux__)

#include <linux/falloc.h>

#endif

#if !defined(WITHOUT_MALLINFO) && defined(__linux__) && defined(__GLIBC__)

#include <malloc.h>

#define WITH_MALLINFO

#endif

#if defined(__FreeBSD__) && defined(RFPROC)

/*

 * On FreeBSD, calling fork() is equivalent to rfork(RFPROC | RFFDG).

 *

 * RFFDG being set means that the file descriptor table is copied,

 * otherwise it's shared. We want the later, otherwise libevent gets

 * messed up.

 *

 * See issue #412

 */

#define fork() rfork(RFPROC)

#endif

/* Daemonization support */

static int lc_daemonize(lua_State *L) {

	pid_t pid;

	if(getppid() == 1) {

		lua_pushboolean(L, 0);

		lua_pushstring(L, "already-daemonized");

		return 2;

	}

	/* Attempt initial fork */

	if((pid = fork()) < 0) {

		/* Forking failed */

		lua_pushboolean(L, 0);

		lua_pushstring(L, "fork-failed");

		return 2;

	} else if(pid != 0) {

		/* We are the parent process */

		lua_pushboolean(L, 1);

		lua_pushinteger(L, pid);

		return 2;

	}

	/* and we are the child process */

	if(setsid() == -1) {

		/* We failed to become session leader */

		/* (we probably already were) */

		lua_pushboolean(L, 0);

		lua_pushstring(L, "setsid-failed");

		return 2;

	}

	/* Make sure accidental use of FDs 0, 1, 2 don't cause weirdness */

	freopen("/dev/null", "r", stdin);

	freopen("/dev/null", "w", stdout);

	freopen("/dev/null", "w", stderr);

	/* Final fork, use it wisely */

	if(fork()) {

		exit(0);

	}

	/* Show's over, let's continue */

	lua_pushboolean(L, 1);

	lua_pushnil(L);

	return 2;

}

/* Syslog support */

static const char *const facility_strings[] = {

	"auth",

#if !(defined(sun) || defined(__sun))

	"authpriv",

#endif

	"cron",

	"daemon",

#if !(defined(sun) || defined(__sun))

	"ftp",

#endif

	"kern",

	"local0",

	"local1",

	"local2",

	"local3",

	"local4",

	"local5",

	"local6",

	"local7",

	"lpr",

	"mail",

	"syslog",

	"user",

	"uucp",

	NULL

};

static int facility_constants[] =	{

	LOG_AUTH,

#if !(defined(sun) || defined(__sun))

	LOG_AUTHPRIV,

#endif

	LOG_CRON,

	LOG_DAEMON,

#if !(defined(sun) || defined(__sun))

	LOG_FTP,

#endif

	LOG_KERN,

	LOG_LOCAL0,

	LOG_LOCAL1,

	LOG_LOCAL2,

	LOG_LOCAL3,

	LOG_LOCAL4,

	LOG_LOCAL5,

	LOG_LOCAL6,

	LOG_LOCAL7,

	LOG_LPR,

	LOG_MAIL,

	LOG_NEWS,

	LOG_SYSLOG,

	LOG_USER,

	LOG_UUCP,

	-1

};

/* "

       The parameter ident in the call of openlog() is probably stored  as-is.

       Thus,  if  the  string  it  points  to  is  changed, syslog() may start

       prepending the changed string, and if the string it points to ceases to

       exist,  the  results  are  undefined.  Most portable is to use a string

       constant.

   " -- syslog manpage

*/

static char *syslog_ident = NULL;

static int lc_syslog_open(lua_State *L) {

	int facility = luaL_checkoption(L, 2, "daemon", facility_strings);

	facility = facility_constants[facility];

	luaL_checkstring(L, 1);

	if(syslog_ident) {

		free(syslog_ident);

	}

	syslog_ident = strdup(lua_tostring(L, 1));

	openlog(syslog_ident, LOG_PID, facility);

	return 0;

}

static const char *const level_strings[] = {

	"debug",

	"info",

	"notice",

	"warn",

	"error",

	NULL

};

static int level_constants[] = 	{

	LOG_DEBUG,

	LOG_INFO,

	LOG_NOTICE,

	LOG_WARNING,

	LOG_CRIT,

	-1

};

static int lc_syslog_log(lua_State *L) {

	int level = level_constants[luaL_checkoption(L, 1, "notice", level_strings)];

	if(lua_gettop(L) == 3) {

		syslog(level, "%s: %s", luaL_checkstring(L, 2), luaL_checkstring(L, 3));

	} else {

		syslog(level, "%s", lua_tostring(L, 2));

	}

	return 0;

}

static int lc_syslog_close(lua_State *L) {

	(void)L;

	closelog();

	if(syslog_ident) {

		free(syslog_ident);

		syslog_ident = NULL;

	}

	return 0;

}

static int lc_syslog_setmask(lua_State *L) {

	int level_idx = luaL_checkoption(L, 1, "notice", level_strings);

	int mask = 0;

	do {

		mask |= LOG_MASK(level_constants[level_idx]);

	} while(++level_idx <= 4);

	setlogmask(mask);

	return 0;

}

/* getpid */

static int lc_getpid(lua_State *L) {

	lua_pushinteger(L, getpid());

	return 1;

}

/* UID/GID functions */

static int lc_getuid(lua_State *L) {

	lua_pushinteger(L, getuid());

	return 1;

}

static int lc_getgid(lua_State *L) {

	lua_pushinteger(L, getgid());

	return 1;

}

static int lc_setuid(lua_State *L) {

	int uid = -1;

	if(lua_gettop(L) < 1) {

		return 0;

	}

	if(!lua_isinteger(L, 1) && lua_tostring(L, 1)) {

		/* Passed UID is actually a string, so look up the UID */

		struct passwd *p;

		p = getpwnam(lua_tostring(L, 1));

		if(!p) {

			lua_pushboolean(L, 0);

			lua_pushstring(L, "no-such-user");

			return 2;

		}

		uid = p->pw_uid;

	} else {

		uid = lua_tointeger(L, 1);

	}

	if(uid > -1) {

		/* Ok, attempt setuid */

		errno = 0;

		if(setuid(uid)) {

			/* Fail */

			lua_pushboolean(L, 0);

			switch(errno) {

				case EINVAL:

					lua_pushstring(L, "invalid-uid");

					break;

				case EPERM:

					lua_pushstring(L, "permission-denied");

					break;

				default:

					lua_pushstring(L, "unknown-error");

			}

			return 2;

		} else {

			/* Success! */

			lua_pushboolean(L, 1);

			return 1;

		}

	}

	/* Seems we couldn't find a valid UID to switch to */

	lua_pushboolean(L, 0);

	lua_pushstring(L, "invalid-uid");

	return 2;

}

static int lc_setgid(lua_State *L) {

	int gid = -1;

	if(lua_gettop(L) < 1) {

		return 0;

	}

	if(!lua_isinteger(L, 1) && lua_tostring(L, 1)) {

		/* Passed GID is actually a string, so look up the GID */

		struct group *g;

		g = getgrnam(lua_tostring(L, 1));

		if(!g) {

			lua_pushboolean(L, 0);

			lua_pushstring(L, "no-such-group");

			return 2;

		}

		gid = g->gr_gid;

	} else {

		gid = lua_tointeger(L, 1);

	}

	if(gid > -1) {

		/* Ok, attempt setgid */

		errno = 0;

		if(setgid(gid)) {

			/* Fail */

			lua_pushboolean(L, 0);

			switch(errno) {

				case EINVAL:

					lua_pushstring(L, "invalid-gid");

					break;

				case EPERM:

					lua_pushstring(L, "permission-denied");

					break;

				default:

					lua_pushstring(L, "unknown-error");

			}

			return 2;

		} else {

			/* Success! */

			lua_pushboolean(L, 1);

			return 1;

		}

	}

	/* Seems we couldn't find a valid GID to switch to */

	lua_pushboolean(L, 0);

	lua_pushstring(L, "invalid-gid");

	return 2;

}

static int lc_initgroups(lua_State *L) {

	int ret;

	gid_t gid;

	struct passwd *p;