4.3BSD/usr/src/games/compat/runcompat.c
static char sccsid[] = "@(#)runcompat.c 4.2 83/07/31";
/*
* Compatability mode support
* written by Art Wetzel during August 1979
* at the Interdisciplinary Dept of Information Science
* Room 711, LIS Bldg
* University of Pittsburgh
* Pittsburgh, Pa 15260
*
* No claims are made on the completeness of the support of any
* of the systems simulated under this package
*/
#include <stdio.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include "defs.h"
#ifdef UNIX
#include "unixhdr.h"
#endif
#ifdef RT11
#include "rt11.h"
#endif
struct stat stat32v;
u_short regs[8];
u_long psl;
u_short *pc;
int incompat;
char *progname;
char *nameend;
main(argc, argv, envp)
int argc;
char **argv, **envp;
{
if (argc < 2) {
fprintf(stderr,"Usage: %s [-rootdir] file args...\n",argv[0]);
exit(1);
}
/* remember where the program name etc should go for using ps */
progname = argv[0];
nameend = envp[0]-1;
argv++;
/* set up alternate root directory if flagged for */
if (*argv[0] == '-') {
if (chroot(argv[0]+1)) {
fprintf(stderr,"Can't change root to %s\n",argv[0]+1);
exit(-1);
}
argv++;
}
/* check out file stats of file to run */
if (stat(argv[0], &stat32v)) {
fprintf(stderr,"%s does not exist\n",argv[0]);
exit(1);
}
/* a version of SETUID and SETGID file executions */
/* the binary of this program should be SETUID root for this to work */
/* requires nonstandard seteuid and setegid sys calls */
if (!(stat32v.st_mode & S_ISGID) || setegid(stat32v.st_gid))
/* if not SETGID file or error, drop back to real group */
setgid(getgid());
if (!(stat32v.st_mode & S_ISUID) || seteuid(stat32v.st_uid))
/* if not SETUID file or error, drop back to real uid */
setuid(getuid());
#ifdef V6UNIX
/* no umasks in version 6 */
umask(0);
#endif
/* go try to execute , passing along args and environment */
execute(argv[0], argv, envp);
/* only get here if execute fails */
fprintf(stderr,"Execution failure on %s\n",argv[0]);
exit(1);
}
execute(file, argv, envp)
char *file, **argv, **envp;
{
int fd, n, tloadpt, dloadpt, tloadsize, dloadsize, stacksize;
register short *p;
extern illtrap();
extern char **environ;
/* file to run should be readable */
if ((fd = open(file, 0)) == -1) {
fprintf(stderr,"Can't open %s for read access\n",file);
return(-1);
}
#ifdef UNIX
if ((n = read(fd, &header, sizeof header)) != sizeof header)
return(ENOEXEC);
/* check to see if really unix file */
if (header.magic != MAGIC1 && header.magic != MAGIC2 &&
header.magic != MAGIC3 && header.magic != MAGIC4) {
return(ENOEXEC);
}
/* if a UNIX file run it */
if (header.textsize == 0) {
close(fd);
/* if no explicit env, pass along environ */
if (!envp || *envp == 0)
return(execve(file, argv, environ));
return(execve(file, argv, envp));
}
/* checks out OK as PDP-11 UNIX file */
if (header.magic == MAGIC3) {
fprintf(stderr,"%s compiled for separate I/D space\n",argv[0]);
return(-1);
}
/* unix text loads at 0 */
tloadpt = 0;
/* set starting pc value */
pc = (unsigned short *)header.entry;
/* figure out where to load initialized data */
dloadpt = tloadsize = header.textsize;
/* check if alignment of data segment to 8k byte boundary */
if (header.magic == MAGIC2)
dloadpt = (dloadpt+8191) & (~8191);
/* how much data */
dloadsize = header.datasize;
stacksize = header.bsssize;
#endif
#ifdef RT11
if ((n = read(fd, shortspace, RTHDRSIZ)) != RTHDRSIZ) {
fprintf(stderr,"Error reading 1st block\n");
return(-1);
}
/* rt11 files are 0 aligned including the header */
tloadpt = RTHDRSIZ;
/* set starting pc value */
pc = (unsigned short *)shortspace[RTPC];
/* initialize stack location */
regs[6] = shortspace[RTSP];
/* figure how much to load */
dloadpt = tloadsize = shortspace[RTHGH]-RTHDRSIZ;
/* no separate data as in unix */
dloadsize = 0;
stacksize = 0;
#endif
/* see if it all fits into available memory space */
if ((dloadpt+dloadsize+stacksize) > (int)memsiz) {
fprintf(stderr,"File too big to run\n");
return(-1);
}
/* read text segment */
if ((n = read(fd, tloadpt, tloadsize)) < tloadsize) {
fprintf(stderr,"Text read failure\n");
return(-1);
}
/* read data segment */
if ((n = read(fd, dloadpt, dloadsize)) < dloadsize) {
fprintf(stderr,"Data read failure\n");
return(-1);
}
/* clear out the rest of memory */
p = (short *)(dloadpt + dloadsize);
while (p < (short *)memsiz)
*p++ = 0;
/* close file before starting it */
close(fd);
/* set up illegal instruction trapping */
signal(SIGILL, illtrap);
/* lets give it a try */
start(argv, envp);
}
illtrap(signum, faultcode, scp)
int signum, faultcode;
struct sigcontext *scp;
{
unsigned short *pcptr;
int instr;
register int i;
extern getregs();
/* record the fact that we are not in compatability mode now */
incompat = 0;
/* get the register values before they get clobbered */
getregs();
/* figure out what the pc was */
pcptr = (unsigned short *) &scp->sc_pc;
pc = (unsigned short *) *pcptr;
/* get the instruction */
instr = *pc;
/* incriment the pc over this instruction */
pc++;
/* set register 7 as pc synonym */
regs[7] = (unsigned short)(int)pc;
/* set up psl with condition codes */
/* a UNIX-32V monitor patch is required to not clear condition codes */
psl = 0x83c00000 | (scp->sc_ps & 017);
sigsetmask(scp->sc_mask);
/* pick out the appropriate action for this illegal instruction */
switch(instr>>8){
case TRAPS:
dotrap(instr & 0377);
break;
case EMTS:
if (sigvals[SIGEMT] && ((sigvals[SIGEMT]%2) != 1)) {
dosig(SIGEMT, pc);
break;
}
doemt(instr & 0377);
break;
default:
if (instr >= 075000 && instr < 075040) {
/* fis instructions */
if (dofloat(instr) == 0)
break;
}
if (instr >= 0170000) {
/* floating point unit instructions */
if (dofloat(instr) == 0)
break;
}
/* genuine illegal instruction */
/* if signal trap set go to user's trap location */
if (sigvals[SIGILL] && ((sigvals[SIGILL]%2) != 1)) {
dosig(SIGILL, pc);
break;
}
/* ignore uncaught setd instructions */
if (instr == SETD)
break;
/* otherwise put out a message and quit */
printf("Illegal instruction, psl 0x%08x, pc 0%04o\n",psl,pc-1);
for (i = 0; i < 7; i++)
printf("0x%04x ",regs[i]);
printf("0x%04x -> 0%o\n",pc-1,instr);
/* set up to dump on illegal instruction */
signal(SIGILL,SIG_DFL);
/* set pc back to bad instruction */
pc--;
/* go do it again for dump */
compat();
}
/* go back to compatability mode */
incompat++;
compat();
}