#include "busybox.h"

#include <dirent.h>

// Must match constants in chpst_main!
#define OPT_verbose  (option_mask32 & 0x2000)
#define OPT_pgrp     (option_mask32 & 0x4000)
#define OPT_nostdin  (option_mask32 & 0x8000)
#define OPT_nostdout (option_mask32 & 0x10000)
#define OPT_nostderr (option_mask32 & 0x20000)

static char *set_user;
static char *env_user;
static const char *env_dir;
static long limitd = -2;
static long limits = -2;
static long limitl = -2;
static long limita = -2;
static long limito = -2;
static long limitp = -2;
static long limitf = -2;
static long limitc = -2;
static long limitr = -2;
static long limitt = -2;
static int nicelvl;
static const char *root;

static void suidgid(char *user)
{
	struct bb_uidgid_t ugid;

	if (!uidgid_get(&ugid, user)) {
		bb_error_msg_and_die("unknown user/group: %s", user);
	}
	if (setgroups(1, &ugid.gid) == -1)
		bb_perror_msg_and_die("setgroups");
	xsetgid(ugid.gid);
	xsetuid(ugid.uid);
}

static void euidgid(char *user)
{
	struct bb_uidgid_t ugid;

	if (!uidgid_get(&ugid, user)) {
		bb_error_msg_and_die("unknown user/group: %s", user);
	}
	xsetenv("GID", utoa(ugid.gid));
	xsetenv("UID", utoa(ugid.uid));
}

static void edir(const char *directory_name)
{
	int wdir;
	DIR *dir;
	struct dirent *d;
	int fd;

	wdir = xopen(".", O_RDONLY | O_NDELAY);
	xchdir(directory_name);
	dir = opendir(".");
	if (!dir)
		bb_perror_msg_and_die("opendir %s", directory_name);
	for (;;) {
		errno = 0;
		d = readdir(dir);
		if (!d) {
			if (errno) bb_perror_msg_and_die("readdir %s", directory_name);
			break;
		}
		if (d->d_name[0] == '.') continue;
		fd = open(d->d_name, O_RDONLY | O_NDELAY);
		if (fd < 0) {
			if ((errno == EISDIR) && env_dir) {
				if (OPT_verbose)
					bb_perror_msg("warning: %s/%s is a directory", directory_name,
						d->d_name);
				continue;
			} else
				bb_perror_msg_and_die("open %s/%s", directory_name, /* was exiting 111 */
				                     d->d_name);
		}
		if (fd >= 0) {
			char buf[256];
			char *tail;
			int size;

			size = safe_read(fd, buf, sizeof(buf)-1);
			if (size < 0)
				bb_perror_msg_and_die("read %s/%s", directory_name, /* was exiting 111 */
						d->d_name);
			if (size == 0) {
				unsetenv(d->d_name);
				continue;
			}
			buf[size] = '\n';
			tail = memchr(buf, '\n', sizeof(buf));
			/* skip trailing whitespace */;
			while (1) {
				if (tail[0]==' ') tail[0] = '\0';
				if (tail[0]=='\t') tail[0] = '\0';
				if (tail[0]=='\n') tail[0] = '\0';
				if (tail == buf) break;
				tail--;
			}
			xsetenv(d->d_name, buf);
		}
	}
	closedir(dir);
	if (fchdir(wdir) == -1) bb_perror_msg_and_die("fchdir");
	close(wdir);
}

static void limit(int what, long l)
{
	struct rlimit r;

	if (getrlimit(what, &r) == -1) bb_perror_msg_and_die("getrlimit");
	if ((l < 0) || (l > r.rlim_max))
		r.rlim_cur = r.rlim_max;
	else
		r.rlim_cur = l;
	if (setrlimit(what, &r) == -1) bb_perror_msg_and_die("setrlimit");
}

static void slimit(void)
{
	if (limitd >= -1) {
#ifdef RLIMIT_DATA
		limit(RLIMIT_DATA, limitd);
#else
		if (OPT_verbose) bb_error_msg("system does not support %s", "RLIMIT_DATA");
#endif
	}
	if (limits >= -1) {
#ifdef RLIMIT_STACK
		limit(RLIMIT_STACK, limits);
#else
		if (OPT_verbose) bb_error_msg("system does not support %s", "RLIMIT_STACK");
#endif
	}
	if (limitl >= -1) {
#ifdef RLIMIT_MEMLOCK
		limit(RLIMIT_MEMLOCK, limitl);
#else
		if (OPT_verbose) bb_error_msg("system does not support %s", "RLIMIT_MEMLOCK");
#endif
	}
	if (limita >= -1) {
#ifdef RLIMIT_VMEM
		limit(RLIMIT_VMEM, limita);
#else
#ifdef RLIMIT_AS
		limit(RLIMIT_AS, limita);
#else
		if (OPT_verbose)
			bb_error_msg("system does not support %s", "RLIMIT_VMEM");
#endif
#endif
	}
	if (limito >= -1) {
#ifdef RLIMIT_NOFILE
		limit(RLIMIT_NOFILE, limito);
#else
#ifdef RLIMIT_OFILE
		limit(RLIMIT_OFILE, limito);
#else
		if (OPT_verbose)
			bb_error_msg("system does not support %s", "RLIMIT_NOFILE");
#endif
#endif
	}
	if (limitp >= -1) {
#ifdef RLIMIT_NPROC
		limit(RLIMIT_NPROC, limitp);
#else
		if (OPT_verbose) bb_error_msg("system does not support %s", "RLIMIT_NPROC");
#endif
	}
	if (limitf >= -1) {
#ifdef RLIMIT_FSIZE
		limit(RLIMIT_FSIZE, limitf);
#else
		if (OPT_verbose) bb_error_msg("system does not support %s", "RLIMIT_FSIZE");
#endif
	}
	if (limitc >= -1) {
#ifdef RLIMIT_CORE
		limit(RLIMIT_CORE, limitc);
#else
		if (OPT_verbose) bb_error_msg("system does not support %s", "RLIMIT_CORE");
#endif
	}
	if (limitr >= -1) {
#ifdef RLIMIT_RSS
		limit(RLIMIT_RSS, limitr);
#else
		if (OPT_verbose) bb_error_msg("system does not support %s", "RLIMIT_RSS");
#endif
	}
	if (limitt >= -1) {
#ifdef RLIMIT_CPU
		limit(RLIMIT_CPU, limitt);
#else
		if (OPT_verbose) bb_error_msg("system does not support %s", "RLIMIT_CPU");
#endif
	}
}

/* argv[0] */
static void setuidgid(int, char **);
static void envuidgid(int, char **);
static void envdir(int, char **);
static void softlimit(int, char **);

int chpst_main(int argc, char **argv)
{
	if (applet_name[3] == 'd') envdir(argc, argv);
	if (applet_name[1] == 'o') softlimit(argc, argv);
	if (applet_name[0] == 's') setuidgid(argc, argv);
	if (applet_name[0] == 'e') envuidgid(argc, argv);
        // otherwise we are.......... chpst

	{
		char *m,*d,*o,*p,*f,*c,*r,*t,*n;
		getopt32(argc, argv, "u:U:e:m:d:o:p:f:c:r:t:/:n:vP012",
				&set_user,&env_user,&env_dir,
				&m,&d,&o,&p,&f,&c,&r,&t,&root,&n);
		// if (option_mask32 & 0x1) // -u
		// if (option_mask32 & 0x2) // -U
		// if (option_mask32 & 0x4) // -e
		if (option_mask32 & 0x8) limits = limitl = limita = limitd = xatoul(m); // -m
		if (option_mask32 & 0x10) limitd = xatoul(d); // -d
		if (option_mask32 & 0x20) limito = xatoul(o); // -o
		if (option_mask32 & 0x40) limitp = xatoul(p); // -p
		if (option_mask32 & 0x80) limitf = xatoul(f); // -f
		if (option_mask32 & 0x100) limitc = xatoul(c); // -c
		if (option_mask32 & 0x200) limitr = xatoul(r); // -r
		if (option_mask32 & 0x400) limitt = xatoul(t); // -t
		// if (option_mask32 & 0x800) // -/
		if (option_mask32 & 0x1000) nicelvl = xatoi(n); // -n
		// The below consts should match #defines at top!
		//if (option_mask32 & 0x2000) OPT_verbose = 1; // -v
		//if (option_mask32 & 0x4000) OPT_pgrp = 1; // -P
		//if (option_mask32 & 0x8000) OPT_nostdin = 1; // -0
		//if (option_mask32 & 0x10000) OPT_nostdout = 1; // -1
		//if (option_mask32 & 0x20000) OPT_nostderr = 1; // -2
	}
	argv += optind;
	if (!argv || !*argv) bb_show_usage();
	
	if (OPT_pgrp) setsid();
	if (env_dir) edir(env_dir);
	if (root) {
		xchdir(root);
		if (chroot(".") == -1)
			bb_perror_msg_and_die("chroot");
	}
	slimit();
	if (nicelvl) {
		errno = 0;
		if (nice(nicelvl) == -1)
			bb_perror_msg_and_die("nice");
	}
	if (env_user) euidgid(env_user);
	if (set_user) suidgid(set_user);
	if (OPT_nostdin) close(0);
	if (OPT_nostdout) close(1);
	if (OPT_nostderr) close(2);
	execvp(argv[0], argv);
	bb_perror_msg_and_die("exec %s", argv[0]);
}

static void setuidgid(int argc, char **argv)
{
	const char *account;

	account = *++argv;
	if (!account) bb_show_usage();
	if (!*++argv) bb_show_usage();
	suidgid((char*)account);
	execvp(argv[0], argv);
	bb_perror_msg_and_die("exec %s", argv[0]);
}

static void envuidgid(int argc, char **argv)
{
	const char *account;

	account = *++argv;
	if (!account) bb_show_usage();
	if (!*++argv) bb_show_usage();
	euidgid((char*)account);
	execvp(argv[0], argv);
	bb_perror_msg_and_die("exec %s", argv[0]);
}

static void envdir(int argc, char **argv)
{
	const char *dir;

	dir = *++argv;
	if (!dir) bb_show_usage();
	if (!*++argv) bb_show_usage();
	edir(dir);
	execvp(argv[0], argv);
	bb_perror_msg_and_die("exec %s", argv[0]);
}

static void softlimit(int argc, char **argv)
{
	char *a,*c,*d,*f,*l,*m,*o,*p,*r,*s,*t;
	getopt32(argc, argv, "a:c:d:f:l:m:o:p:r:s:t:",
			&a,&c,&d,&f,&l,&m,&o,&p,&r,&s,&t);
	if (option_mask32 & 0x001) limita = xatoul(a); // -a
	if (option_mask32 & 0x002) limitc = xatoul(c); // -c
	if (option_mask32 & 0x004) limitd = xatoul(d); // -d
	if (option_mask32 & 0x008) limitf = xatoul(f); // -f
	if (option_mask32 & 0x010) limitl = xatoul(l); // -l
	if (option_mask32 & 0x020) limits = limitl = limita = limitd = xatoul(m); // -m
	if (option_mask32 & 0x040) limito = xatoul(o); // -o
	if (option_mask32 & 0x080) limitp = xatoul(p); // -p
	if (option_mask32 & 0x100) limitr = xatoul(r); // -r
	if (option_mask32 & 0x200) limits = xatoul(s); // -s
	if (option_mask32 & 0x400) limitt = xatoul(t); // -t
	argv += optind;
	if (!argv[0]) bb_show_usage();
	slimit();
	execvp(argv[0], argv);
	bb_perror_msg_and_die("exec %s", argv[0]);
}