/*
	This chroot command does very little. Once the chroot
	system call is executed, it (option) remove the CAP_SYS_CHROOT
	capability. Then it executes its argument
*/
#include <stdio.h>
#include <string.h>
#include <pwd.h>
#include <grp.h>
#include <errno.h>
#include <unistd.h>
#include "vutil.h"
#include <linux/capability.h>
#include "old_syscall.p"

static int my_chroot(const char *dir)
{
	int ret = -1;
	if (has_chrootsafe()){
		ret = call_chrootsafe(dir);
	}else{
		// fprintf (stderr,"Kernel do not support chrootsafe(), using chroot()\n");
		ret = chroot (dir);
	}
	return ret;
}

int main (int argc, char *argv[])
{
	if (argc < 3){
		fprintf (stderr,"capchroot version %s\n",VERSION);
		fprintf (stderr
			,"capchroot [--nochroot] [--suid user] directory command argument\n"
			 "\n"
			 "--nochroot   remove the CAP_SYS_CHROOT capability\n"
			 "             after the chroot system call.\n"
			 "--suid user  switch to a different user (in the vserver context)\n"
			 "             before executing the command.\n");
	} else {
		const char *uid = NULL;
		bool nochroot = false;
		int dir;
		for (dir=1; dir<argc; dir++){
			const char *arg = argv[dir];
			if (arg[0] != '-' && arg[1] != '-'){
				break;
			}else if (strcmp(arg,"--nochroot")==0){
				nochroot = true;
			}else if (strcmp(arg,"--suid")==0){
				dir++;
				uid = argv[dir];
			}
			
		}
		// We resolve the UID before doing the chroot.
		// If we do the getpwnam after the chroot, we will end
		// up loading shared object from the vserver.
		// This is causing two kind of problem: Incompatibilities
		// and also a security flaw. The shared objects in the vserver
		// may be tweaked to get control of the root server ...
		getpwnam ("root");
		if (my_chroot (argv[dir]) == -1){
			fprintf (stderr,"Can't chroot to directory %s (%s)\n",argv[dir]
				,strerror(errno));
		}else{
			if (nochroot){
				call_new_s_context (0,NULL,1<<CAP_SYS_CHROOT,0,0);
			}

			struct passwd *p = NULL;
			if (uid != NULL && strcmp(uid,"root")!=0){
				p = getpwnam(uid);
				if (p == NULL){
					fprintf (stderr,"User not found: %s\n",uid);
					exit (-1);
				}
			}
			if (p != NULL) {
				if (initgroups(uid, p->pw_gid) == -1){
					fprintf(stderr,"initgroups error: %s\n" ,strerror(errno)) ;
					exit(-1) ;
				}
				if (setgid(p->pw_gid) == -1){
					fprintf(stderr,"setgid error: %s\n" ,strerror(errno)) ;
					exit(-1) ;
				}
				if (setuid(p->pw_uid) == -1){
					fprintf(stderr,"setuid error: %s\n" ,strerror(errno)) ;
					exit(-1) ;
				}
				setenv("HOME", p->pw_dir, 1) ;
				setenv("SHELL", p->pw_shell, 1) ;
				setenv("USER", p->pw_name, 1) ;
				setenv("LOGNAME", p->pw_name, 1) ;
			}
			int cmd = dir + 1;
			if (cmd >= argc){
				fprintf (stderr,"capchroot: No command to execute, do nothing\n");
			}else{
				#if 0
				for (int i=cmd; i<argc; i++){
					printf ("argv[%d]=:%s:\n",i,argv[i]);
				}
				#endif
				execvp (argv[cmd],argv+cmd);
				fprintf (stderr,"Can't execute %s (%s)\n",argv[cmd]
					,strerror(errno));
			}
		}
	}
	return -1;
}