1 static char sccsid[] = "@(#)runcompat.c 4.2 83/07/31";
2
3 /*
4 * Compatability mode support
5 * written by Art Wetzel during August 1979
6 * at the Interdisciplinary Dept of Information Science
7 * Room 711, LIS Bldg
8 * University of Pittsburgh
9 * Pittsburgh, Pa 15260
10 *
11 * No claims are made on the completeness of the support of any
12 * of the systems simulated under this package
13 */
14
15 #include <stdio.h>
16 #include <signal.h>
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <errno.h>
20 #include "defs.h"
21 #ifdef UNIX
22 #include "unixhdr.h"
23 #endif
24 #ifdef RT11
25 #include "rt11.h"
26 #endif
27
28 struct stat stat32v;
29 u_short regs[8];
30 u_long psl;
31 u_short *pc;
32 int incompat;
33 char *progname;
34 char *nameend;
35
main(argc,argv,envp)36 main(argc, argv, envp)
37 int argc;
38 char **argv, **envp;
39 {
40
41 if (argc < 2) {
42 fprintf(stderr,"Usage: %s [-rootdir] file args...\n",argv[0]);
43 exit(1);
44 }
45 /* remember where the program name etc should go for using ps */
46 progname = argv[0];
47 nameend = envp[0]-1;
48 argv++;
49 /* set up alternate root directory if flagged for */
50 if (*argv[0] == '-') {
51 if (chroot(argv[0]+1)) {
52 fprintf(stderr,"Can't change root to %s\n",argv[0]+1);
53 exit(-1);
54 }
55 argv++;
56 }
57 /* check out file stats of file to run */
58 if (stat(argv[0], &stat32v)) {
59 fprintf(stderr,"%s does not exist\n",argv[0]);
60 exit(1);
61 }
62 /* a version of SETUID and SETGID file executions */
63 /* the binary of this program should be SETUID root for this to work */
64 /* requires nonstandard seteuid and setegid sys calls */
65 if (!(stat32v.st_mode & S_ISGID) || setegid(stat32v.st_gid))
66 /* if not SETGID file or error, drop back to real group */
67 setgid(getgid());
68 if (!(stat32v.st_mode & S_ISUID) || seteuid(stat32v.st_uid))
69 /* if not SETUID file or error, drop back to real uid */
70 setuid(getuid());
71 #ifdef V6UNIX
72 /* no umasks in version 6 */
73 umask(0);
74 #endif
75 /* go try to execute , passing along args and environment */
76 execute(argv[0], argv, envp);
77 /* only get here if execute fails */
78 fprintf(stderr,"Execution failure on %s\n",argv[0]);
79 exit(1);
80 }
81
execute(file,argv,envp)82 execute(file, argv, envp)
83 char *file, **argv, **envp;
84 {
85 int fd, n, tloadpt, dloadpt, tloadsize, dloadsize, stacksize;
86 register short *p;
87 extern illtrap();
88 extern char **environ;
89
90 /* file to run should be readable */
91 if ((fd = open(file, 0)) == -1) {
92 fprintf(stderr,"Can't open %s for read access\n",file);
93 return(-1);
94 }
95 #ifdef UNIX
96 if ((n = read(fd, &header, sizeof header)) != sizeof header)
97 return(ENOEXEC);
98 /* check to see if really unix file */
99 if (header.magic != MAGIC1 && header.magic != MAGIC2 &&
100 header.magic != MAGIC3 && header.magic != MAGIC4) {
101 return(ENOEXEC);
102 }
103 /* if a UNIX file run it */
104 if (header.textsize == 0) {
105 close(fd);
106 /* if no explicit env, pass along environ */
107 if (!envp || *envp == 0)
108 return(execve(file, argv, environ));
109 return(execve(file, argv, envp));
110 }
111 /* checks out OK as PDP-11 UNIX file */
112 if (header.magic == MAGIC3) {
113 fprintf(stderr,"%s compiled for separate I/D space\n",argv[0]);
114 return(-1);
115 }
116 /* unix text loads at 0 */
117 tloadpt = 0;
118 /* set starting pc value */
119 pc = (unsigned short *)header.entry;
120 /* figure out where to load initialized data */
121 dloadpt = tloadsize = header.textsize;
122 /* check if alignment of data segment to 8k byte boundary */
123 if (header.magic == MAGIC2)
124 dloadpt = (dloadpt+8191) & (~8191);
125 /* how much data */
126 dloadsize = header.datasize;
127 stacksize = header.bsssize;
128 #endif
129 #ifdef RT11
130 if ((n = read(fd, shortspace, RTHDRSIZ)) != RTHDRSIZ) {
131 fprintf(stderr,"Error reading 1st block\n");
132 return(-1);
133 }
134 /* rt11 files are 0 aligned including the header */
135 tloadpt = RTHDRSIZ;
136 /* set starting pc value */
137 pc = (unsigned short *)shortspace[RTPC];
138 /* initialize stack location */
139 regs[6] = shortspace[RTSP];
140 /* figure how much to load */
141 dloadpt = tloadsize = shortspace[RTHGH]-RTHDRSIZ;
142 /* no separate data as in unix */
143 dloadsize = 0;
144 stacksize = 0;
145 #endif
146 /* see if it all fits into available memory space */
147 if ((dloadpt+dloadsize+stacksize) > (int)memsiz) {
148 fprintf(stderr,"File too big to run\n");
149 return(-1);
150 }
151 /* read text segment */
152 if ((n = read(fd, tloadpt, tloadsize)) < tloadsize) {
153 fprintf(stderr,"Text read failure\n");
154 return(-1);
155 }
156 /* read data segment */
157 if ((n = read(fd, dloadpt, dloadsize)) < dloadsize) {
158 fprintf(stderr,"Data read failure\n");
159 return(-1);
160 }
161 /* clear out the rest of memory */
162 p = (short *)(dloadpt + dloadsize);
163 while (p < (short *)memsiz)
164 *p++ = 0;
165 /* close file before starting it */
166 close(fd);
167 /* set up illegal instruction trapping */
168 signal(SIGILL, illtrap);
169 /* lets give it a try */
170 start(argv, envp);
171 }
172
illtrap(signum,faultcode,scp)173 illtrap(signum, faultcode, scp)
174 int signum, faultcode;
175 struct sigcontext *scp;
176 {
177 unsigned short *pcptr;
178 int instr;
179 register int i;
180 extern getregs();
181
182 /* record the fact that we are not in compatability mode now */
183 incompat = 0;
184 /* get the register values before they get clobbered */
185 getregs();
186 /* figure out what the pc was */
187 pcptr = (unsigned short *) &scp->sc_pc;
188 pc = (unsigned short *) *pcptr;
189 /* get the instruction */
190 instr = *pc;
191 /* incriment the pc over this instruction */
192 pc++;
193 /* set register 7 as pc synonym */
194 regs[7] = (unsigned short)(int)pc;
195 /* set up psl with condition codes */
196 /* a UNIX-32V monitor patch is required to not clear condition codes */
197 psl = 0x83c00000 | (scp->sc_ps & 017);
198 sigsetmask(scp->sc_mask);
199 /* pick out the appropriate action for this illegal instruction */
200 switch(instr>>8){
201
202 case TRAPS:
203 dotrap(instr & 0377);
204 break;
205
206 case EMTS:
207 if (sigvals[SIGEMT] && ((sigvals[SIGEMT]%2) != 1)) {
208 dosig(SIGEMT, pc);
209 break;
210 }
211 doemt(instr & 0377);
212 break;
213
214 default:
215 if (instr >= 075000 && instr < 075040) {
216 /* fis instructions */
217 if (dofloat(instr) == 0)
218 break;
219 }
220 if (instr >= 0170000) {
221 /* floating point unit instructions */
222 if (dofloat(instr) == 0)
223 break;
224 }
225 /* genuine illegal instruction */
226 /* if signal trap set go to user's trap location */
227 if (sigvals[SIGILL] && ((sigvals[SIGILL]%2) != 1)) {
228 dosig(SIGILL, pc);
229 break;
230 }
231 /* ignore uncaught setd instructions */
232 if (instr == SETD)
233 break;
234 /* otherwise put out a message and quit */
235 printf("Illegal instruction, psl 0x%08x, pc 0%04o\n",psl,pc-1);
236 for (i = 0; i < 7; i++)
237 printf("0x%04x ",regs[i]);
238 printf("0x%04x -> 0%o\n",pc-1,instr);
239 /* set up to dump on illegal instruction */
240 signal(SIGILL,SIG_DFL);
241 /* set pc back to bad instruction */
242 pc--;
243 /* go do it again for dump */
244 compat();
245 }
246 /* go back to compatability mode */
247 incompat++;
248 compat();
249 }
250