ecuungetty.c

一个通讯程序源码

char *revision = "@(#)ecuungetty 3.20";

#if defined(SHARE_DEBUG)
#ifndef ECUUNGETTY_DEBUG
#define ECUUNGETTY_DEBUG
#endif
#endif

/*+-------------------------------------------------------------------------
	ecuungetty.c - ecu "ungetty" program
	[e-mail]

Get a line:
ecuungetty /dev/ttyxx <bamboozle-str>
ecuungetty -g /dev/ttyxx <bamboozle-str>

Test a line's atatus:
ecuungetty -t /dev/ttyxx <bamboozle-str>

Return a line:
ecuungetty -r /dev/ttyxx <bamboozle-str>

  Defined functions:
	assign_tty(tty,uid,gid,mode)
	ecu_log_event(pid,event_note)
	errno_text(errnum)
	eug_exit(code)
	main(argc,argv,envp)
	termecu()

No effort is made to close the passwd file with endpwent().
I use setpwent() instead.  It is so contrary for me to leave
a file open that I just had to put a reminder to myself here.
If the program lived for more than 1/2 second, I'd probably
keep to my usual practice.
--------------------------------------------------------------------------*/
/*+:EDITS:*/
/*:09-10-1992-13:59-wht@n4hgf-ECU release 3.20 */
/*:09-02-1992-07:10-wht@n4hgf-DEBUG now gets actual user log file name */
/*:09-02-1992-06:48-wht@n4hgf-UG_RESTART exit any time we chown tty to user */
/*:08-22-1992-15:38-wht@n4hgf-ECU release 3.20 BETA */
/*:08-16-1992-01:59-wht@n4hgf-absolutely ensure no chown/chmod of /dev/tty */
/*:08-07-1992-18:50-wht@n4hgf-chown/chmod both tty names on SCO */
/*:07-19-1992-09:07-wht@n4hgf-"rudimentary" security/validity checks on tty */
/*:06-19-1992-20:27-root@n4hgf-needed ECUUNGETTY_CHOWN in another place */
/*:06-04-1992-12:21-wht@n4hgf-chown/chmod with debugging */
/*:04-27-1992-19:30-wht@n4hgf-add optional chown/chmod */
/*:04-24-1992-20:12-wht@[e-mail] found long time bug - bad kill */
/*:08-10-1991-17:39-wht@n4hgf-US_WEGOTIT handling */
/*:08-07-1991-14:15-wht@n4hgf-add debug log event code */
/*:07-25-1991-12:57-wht@n4hgf-ECU release 3.10 */
/*:09-19-1990-19:36-wht@n4hgf-ecu_log_event now gets pid for log from caller */
/*:08-14-1990-20:40-wht@n4hgf-ecu3.00-flush old edit history */

#include <stdio.h>
#include <ctype.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include "../ecu_types.h"
#include "../ecu_stat.h"
#include <utmp.h>
#include <sys/locking.h>
#include "../ecuungetty.h"
#include "../utmpstatus.h"
#include "../ttynaming.h"

#ifdef ECUUNGETTY_CHOWN
#include <pwd.h>
struct passwd *uupw;
struct passwd uucp_pwd;
#endif

void eug_exit();

extern struct utmp last_utmp;

int real_uid;
int xmtr_pid;
struct stat tstat;

char **gargv;
int gargc;

#if defined(ECUUNGETTY_DEBUG)
char s256[256];
#endif /* ECUUNGETTY_DEBUG */

/*+-------------------------------------------------------------------------
	ecu_log_event(pid,event_note)
--------------------------------------------------------------------------*/
void
ecu_log_event(pid,event_note)
int pid;
char *event_note;
{
#if defined(ECUUNGETTY_DEBUG)
	FILE *ecu_log_fp;
	static char logname[256] = "";

	if(!logname[0])
	{
		struct passwd *uidpw;
		setpwent();
		if(!(uidpw = getpwuid(real_uid)))
			eug_exit(UGE_LOGIC);
		strcpy(logname,uidpw->pw_dir);
		strcat(logname,"/.ecu/log");
	}

	if((ecu_log_fp = fopen(logname,"a")) != NULL)
	{
		locking(fileno(ecu_log_fp),LK_LOCK,0L);
		fputs("ECUUNGET",ecu_log_fp);
		fprintf(ecu_log_fp,"-%05d-(%05d) ",getppid(),pid);
		fputs(event_note,ecu_log_fp);
		fputs("\n",ecu_log_fp);
		fflush(ecu_log_fp);
		locking(fileno(ecu_log_fp),LK_UNLCK,0L);
		fclose(ecu_log_fp);
	}
#endif
}	/* end of ecu_log_event */

/*+-------------------------------------------------------------------------
	assign_tty(tty,uid,gid,mode) - set a tty owner, group, mode

returns 0 on success, -1 on error
--------------------------------------------------------------------------*/
int
assign_tty(tty,uid,gid,mode)
char *tty;
int uid;
int gid;
int mode;
{
#ifndef ECUUNGETTY_CHOWN
	return(0);
#else
#if defined(ECUUNGETTY_DEBUG)
	struct stat tstat2;
#endif /* ECUUNGETTY_DEBUG */
#ifdef SCO_TTY_NAMING
	char other_tty[128];
	int itmp;
	char *cptr;
#endif /* SCO_TTY_NAMING */
#if defined(ECUUNGETTY_DEBUG) && defined(SCO_TTY_NAMING)
	struct stat otstat;
#endif /* ECUUNGETTY_DEBUG && SCO_TTY_NAMING */

	if(!strcmp(tty,"/dev/tty"))	/* somebody reported this is still happening */
		eug_exit(UGE_BADARGV);

#ifdef SCO_TTY_NAMING
	itmp = strlen(tty);
	if(itmp > 1)
	{
		strcpy(other_tty,tty);
		cptr = other_tty + itmp - 1;
		if(isalpha(*cptr))
			*cptr = (isupper(*cptr)) ? tolower(*cptr) : toupper(*cptr);
#if defined(ECUUNGETTY_DEBUG)
		stat(other_tty,&otstat);
#endif /* ECUUNGETTY_DEBUG */
		chown(other_tty,uid,gid);
		chmod(other_tty,(unsigned short)mode);
	}
#endif /* SCO_TTY_NAMING */

	chown(tty,uid,gid);
	chmod(tty,(unsigned short)mode);

#if defined(ECUUNGETTY_DEBUG)
	stat(tty,&tstat2);
	sprintf(s256,"TTY '%s' o=(%d,%d) m=0%o (was %d,%d,0%o)",
		tty,
		tstat2.st_uid,tstat2.st_gid,tstat2.st_mode & 0777,
		tstat.st_uid,tstat.st_gid,tstat.st_mode & 0777);
	ecu_log_event(getpid(),s256);
#ifdef SCO_TTY_NAMING
	stat(other_tty,&tstat2);
	sprintf(s256,"TTY '%s' o=(%d,%d) m=0%o (was %d,%d,0%o)",
		other_tty,
		tstat2.st_uid,tstat2.st_gid,tstat2.st_mode & 0777,
		otstat.st_uid,otstat.st_gid,otstat.st_mode & 0777);
	ecu_log_event(getpid(),s256);
#endif /* SCO_TTY_NAMING */
#endif /* ECUUNGETTY_DEBUG */

#endif /* ECUUNGETTY_CHOWN */
}	/* end of assign_tty */

/*+-------------------------------------------------------------------------
	eug_exit(code) - exit() with debug logging
--------------------------------------------------------------------------*/
void
eug_exit(code)
int code;
{
#if defined(ECUUNGETTY_DEBUG)
	int iargv;
	char s1024[1024];
	s1024[0] = 0;
	for(iargv = 1; iargv < gargc; iargv++)
	{
		strcat(s1024,gargv[iargv]);
		strcat(s1024," ");
	}
	sprintf(s1024 + strlen(s1024),"exit code %d",code);
	ecu_log_event(getpid(),s1024);
#endif
	exit(code);
}	/* end of eug_exit */

/*+-------------------------------------------------------------------------
	termecu() - "dummy" for utmpstat.c

This particular incantation will only be called if utmp is non-existent
or not readable.......
--------------------------------------------------------------------------*/
termecu()
{
	eug_exit(UGE_LOGIC);
}	/* end of hangup */

/*+-------------------------------------------------------------------------
	errno_text(errnum)
--------------------------------------------------------------------------*/
char *
errno_text(errnum)
int errnum;
{
	static char errstr[16];
	sprintf(errstr,"%d",errnum);
	return(errstr);
}	/* end of errno_text */

/*+-------------------------------------------------------------------------
	main(argc,argv,envp)
--------------------------------------------------------------------------*/
main(argc,argv,envp)
int argc;
char **argv;
char **envp;
{
	int op = 'g';	/* assume "get" operation */
	int status;
	int itmp;
	char *cptr;
	char *tty = argv[1];
	char *bamboozlement = argv[2];
	char *bamboozle();

	gargv = argv;
	gargc = argc;

	real_uid = getuid();
	if(geteuid())
		eug_exit(UGE_NOTROOT);

#ifdef ECUUNGETTY_CHOWN
	if(!(uupw = getpwnam("uucp")))
		eug_exit(UGE_NOUUCP);
	uucp_pwd = *uupw;
	uupw = &uucp_pwd;
#endif

	if(*argv[1] == '-')
	{
		switch(op = *(argv[1] + 1))
		{
		case 'r':
		case 't':
			break;
		default:
			eug_exit(UGE_BADSWITCH);
		}
		if(argc < 3)
			eug_exit(UGE_BADARGC);
		tty = argv[2];
		bamboozlement = argv[3];
	}
	else if(argc <= 2)
		eug_exit(UGE_BADARGC);

	if(real_uid)	/* if caller not actually root */
	{
		if(strcmp(bamboozlement,bamboozle(getppid())))
			eug_exit(UGE_CALLER);
	}

	/*
	 * rudimentary checks
	 * must be in /dev, no ".." in path,not /dev/tty,must be char special
	 */
	if(strncmp(tty,"/dev/",5))
		eug_exit(UGE_BADARGV);
	if((cptr = strchr(tty,'.')) && (*(cptr + 1) == '.'))
		eug_exit(UGE_BADARGV);
	if(!strcmp(tty,"/dev/tty"))
		eug_exit(UGE_BADARGV);
	if(stat(tty,&tstat))
	{
#if defined(ECUUNGETTY_DEBUG)
		sprintf(s256,"TTY '%s' stat error %d",tty,errno);
		ecu_log_event(getpid(),s256);
#endif /* ECUUNGETTY_DEBUG */
		eug_exit(UGE_BADARGV);
	}
	if((tstat.st_mode & S_IFMT) != S_IFCHR)
		eug_exit(UGE_BADARGV);

	xmtr_pid = getppid();
	status = utmp_status(tty);
#if defined(ECUUNGETTY_DEBUG)
	sprintf(s256,"-%c utmp status=%d",op,status);
	ecu_log_event(getpid(),s256);
#endif

	switch(op)
	{
	case 'g':
		switch(status)
		{
		case US_NOTFOUND:	/* not in utmp, or getty dead */
			itmp = assign_tty(tty,real_uid,getgid(),0622);
			eug_exit((itmp) ? UG_NOTENAB : UG_RESTART);
		case US_LOGIN:		/* enabled for login, idle */
			kill(last_utmp.ut_pid,SIGUSR1);
			nap(200L);
			itmp = assign_tty(tty,real_uid,getgid(),0622);
			eug_exit((itmp) ? UG_NOTENAB : UG_RESTART);
		case US_DIALOUT:	/* enabled for login, currently dialout */
		case US_LOGGEDIN:	/* enabled for login, in use */
			eug_exit(UG_FAIL);
		case US_WEGOTIT:	/* we on it */
			itmp = assign_tty(tty,real_uid,getgid(),0622);
#if 1
			eug_exit((itmp) ? UG_NOTENAB : UG_RESTART);
#else
			if(!kill(last_utmp.ut_pid,0))	/* is there a getty? */
				eug_exit(UG_RESTART);		/* yes */
			else
				eug_exit(UG_NOTENAB);
#endif
		}
		break;

	case 't':	/* no longer called by ecu as of BETA 3.20.02 */
		switch(status)
		{
		case US_NOTFOUND:	/* not in utmp, or getty dead */
#ifdef ECUUNGETTY_CHOWN
			assign_tty(tty,uupw->pw_uid,uupw->pw_gid,0640);
#endif
			eug_exit(UGE_T_NOTFOUND);
		case US_LOGIN:		/* enabled for login, idle */
			eug_exit(UGE_T_LOGIN);
		case US_LOGGEDIN:	/* enabled for login, in use */
			eug_exit(UGE_T_LOGGEDIN);
		case US_WEGOTIT:	/* we have the line */
#ifdef ECUUNGETTY_CHOWN
			assign_tty(tty,uupw->pw_uid,uupw->pw_gid,0640);
#endif
			eug_exit(UG_RESTART);
		case US_DIALOUT:	/* enabled for login, currently dialout */
			eug_exit(UG_RESTART);
		}
		break;

	case 'r':
		switch(status)
		{
		case US_NOTFOUND:	/* not in utmp, or getty dead */
		case US_LOGIN:		/* enabled for login, idle */
#ifdef ECUUNGETTY_CHOWN
			assign_tty(tty,uupw->pw_uid,uupw->pw_gid,0640);
#endif
			eug_exit(0);
		case US_LOGGEDIN:	/* enabled for login, in use */
			eug_exit(0);
		case US_WEGOTIT:	/* we own it */
		case US_DIALOUT:	/* enabled for login, currently dialout */
#ifdef ECUUNGETTY_CHOWN
			assign_tty(tty,uupw->pw_uid,uupw->pw_gid,0640);
#endif
			itmp = 5;
			while(itmp--)
			{
				if(kill(last_utmp.ut_pid,SIGUSR2))
					break;
				nap(100L);
			}
			eug_exit(0);
		}
		break;
	}
	eug_exit(UGE_LOGIC);
}	/* end of main */

/* vi: set tabstop=4 shiftwidth=4: */
/* end of ecuungetty.c */