1 /*-
2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/param.h> /* to pick up __FreeBSD_version */
28 #include <string.h>
29 #include <stand.h>
30 #include "bootstrap.h"
31 #include "ficl.h"
32
33 INTERP_DEFINE("4th");
34
35 /* #define BFORTH_DEBUG */
36
37 #ifdef BFORTH_DEBUG
38 #define DPRINTF(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args)
39 #else
40 #define DPRINTF(fmt, args...) ((void)0)
41 #endif
42
43 /*
44 * Eventually, all builtin commands throw codes must be defined
45 * elsewhere, possibly bootstrap.h. For now, just this code, used
46 * just in this file, it is getting defined.
47 */
48 #define BF_PARSE 100
49
50 /*
51 * FreeBSD loader default dictionary cells
52 */
53 #ifndef BF_DICTSIZE
54 #define BF_DICTSIZE 10000
55 #endif
56
57 /*
58 * BootForth Interface to Ficl Forth interpreter.
59 */
60
61 FICL_SYSTEM *bf_sys;
62 FICL_VM *bf_vm;
63
64 /*
65 * Shim for taking commands from BF and passing them out to 'standard'
66 * argv/argc command functions.
67 */
68 static void
bf_command(FICL_VM * vm)69 bf_command(FICL_VM *vm)
70 {
71 char *name, *line, *tail, *cp;
72 size_t len;
73 struct bootblk_command **cmdp;
74 bootblk_cmd_t *cmd;
75 int nstrings, i;
76 int argc, result;
77 char **argv;
78
79 /* Get the name of the current word */
80 name = vm->runningWord->name;
81
82 /* Find our command structure */
83 cmd = NULL;
84 SET_FOREACH(cmdp, Xcommand_set) {
85 if (((*cmdp)->c_name != NULL) && !strcmp(name, (*cmdp)->c_name))
86 cmd = (*cmdp)->c_fn;
87 }
88 if (cmd == NULL)
89 panic("callout for unknown command '%s'", name);
90
91 /* Check whether we have been compiled or are being interpreted */
92 if (stackPopINT(vm->pStack)) {
93 /*
94 * Get parameters from stack, in the format:
95 * an un ... a2 u2 a1 u1 n --
96 * Where n is the number of strings, a/u are pairs of
97 * address/size for strings, and they will be concatenated
98 * in LIFO order.
99 */
100 nstrings = stackPopINT(vm->pStack);
101 for (i = 0, len = 0; i < nstrings; i++)
102 len += stackFetch(vm->pStack, i * 2).i + 1;
103 line = malloc(strlen(name) + len + 1);
104 strcpy(line, name);
105
106 if (nstrings)
107 for (i = 0; i < nstrings; i++) {
108 len = stackPopINT(vm->pStack);
109 cp = stackPopPtr(vm->pStack);
110 strcat(line, " ");
111 strncat(line, cp, len);
112 }
113 } else {
114 /* Get remainder of invocation */
115 tail = vmGetInBuf(vm);
116 for (cp = tail, len = 0; cp != vm->tib.end && *cp != 0 && *cp != '\n'; cp++, len++)
117 ;
118
119 line = malloc(strlen(name) + len + 2);
120 strcpy(line, name);
121 if (len > 0) {
122 strcat(line, " ");
123 strncat(line, tail, len);
124 vmUpdateTib(vm, tail + len);
125 }
126 }
127 DPRINTF("cmd '%s'", line);
128
129 command_errmsg = command_errbuf;
130 command_errbuf[0] = 0;
131 if (!parse(&argc, &argv, line)) {
132 result = (cmd)(argc, argv);
133 free(argv);
134 } else {
135 result=BF_PARSE;
136 }
137
138 switch (result) {
139 case CMD_CRIT:
140 printf("%s\n", command_errmsg);
141 command_errmsg = NULL;
142 break;
143 case CMD_FATAL:
144 panic("%s", command_errmsg);
145 }
146
147 free(line);
148 /*
149 * If there was error during nested ficlExec(), we may no longer have
150 * valid environment to return. Throw all exceptions from here.
151 */
152 if (result != CMD_OK)
153 vmThrow(vm, result);
154
155 /* This is going to be thrown!!! */
156 stackPushINT(vm->pStack,result);
157 }
158
159 /*
160 * Replace a word definition (a builtin command) with another
161 * one that:
162 *
163 * - Throw error results instead of returning them on the stack
164 * - Pass a flag indicating whether the word was compiled or is
165 * being interpreted.
166 *
167 * There is one major problem with builtins that cannot be overcome
168 * in anyway, except by outlawing it. We want builtins to behave
169 * differently depending on whether they have been compiled or they
170 * are being interpreted. Notice that this is *not* the interpreter's
171 * current state. For example:
172 *
173 * : example ls ; immediate
174 * : problem example ; \ "ls" gets executed while compiling
175 * example \ "ls" gets executed while interpreting
176 *
177 * Notice that, though the current state is different in the two
178 * invocations of "example", in both cases "ls" has been
179 * *compiled in*, which is what we really want.
180 *
181 * The problem arises when you tick the builtin. For example:
182 *
183 * : example-1 ['] ls postpone literal ; immediate
184 * : example-2 example-1 execute ; immediate
185 * : problem example-2 ;
186 * example-2
187 *
188 * We have no way, when we get EXECUTEd, of knowing what our behavior
189 * should be. Thus, our only alternative is to "outlaw" this. See RFI
190 * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related
191 * problem, concerning compile semantics.
192 *
193 * The problem is compounded by the fact that "' builtin CATCH" is valid
194 * and desirable. The only solution is to create an intermediary word.
195 * For example:
196 *
197 * : my-ls ls ;
198 * : example ['] my-ls catch ;
199 *
200 * So, with the below implementation, here is a summary of the behavior
201 * of builtins:
202 *
203 * ls -l \ "interpret" behavior, ie,
204 * \ takes parameters from TIB
205 * : ex-1 s" -l" 1 ls ; \ "compile" behavior, ie,
206 * \ takes parameters from the stack
207 * : ex-2 ['] ls catch ; immediate \ undefined behavior
208 * : ex-3 ['] ls catch ; \ undefined behavior
209 * ex-2 ex-3 \ "interpret" behavior,
210 * \ catch works
211 * : ex-4 ex-2 ; \ "compile" behavior,
212 * \ catch does not work
213 * : ex-5 ex-3 ; immediate \ same as ex-2
214 * : ex-6 ex-3 ; \ same as ex-3
215 * : ex-7 ['] ex-1 catch ; \ "compile" behavior,
216 * \ catch works
217 * : ex-8 postpone ls ; immediate \ same as ex-2
218 * : ex-9 postpone ls ; \ same as ex-3
219 *
220 * As the definition below is particularly tricky, and it's side effects
221 * must be well understood by those playing with it, I'll be heavy on
222 * the comments.
223 *
224 * (if you edit this definition, pay attention to trailing spaces after
225 * each word -- I warned you! :-) )
226 */
227 #define BUILTIN_CONSTRUCTOR \
228 ": builtin: " \
229 ">in @ " /* save the tib index pointer */ \
230 "' " /* get next word's xt */ \
231 "swap >in ! " /* point again to next word */ \
232 "create " /* create a new definition of the next word */ \
233 ", " /* save previous definition's xt */ \
234 "immediate " /* make the new definition an immediate word */ \
235 \
236 "does> " /* Now, the *new* definition will: */ \
237 "state @ if " /* if in compiling state: */ \
238 "1 postpone literal " /* pass 1 flag to indicate compile */ \
239 "@ compile, " /* compile in previous definition */ \
240 "postpone throw " /* throw stack-returned result */ \
241 "else " /* if in interpreting state: */ \
242 "0 swap " /* pass 0 flag to indicate interpret */ \
243 "@ execute " /* call previous definition */ \
244 "throw " /* throw stack-returned result */ \
245 "then ; "
246
247 /*
248 * Initialise the Forth interpreter, create all our commands as words.
249 */
250 void
bf_init(void)251 bf_init(void)
252 {
253 struct bootblk_command **cmdp;
254 char create_buf[41]; /* 31 characters-long builtins */
255 int fd;
256
257 bf_sys = ficlInitSystem(BF_DICTSIZE);
258 bf_vm = ficlNewVM(bf_sys);
259
260 /* Put all private definitions in a "builtins" vocabulary */
261 ficlExec(bf_vm, "vocabulary builtins also builtins definitions");
262
263 /* Builtin constructor word */
264 ficlExec(bf_vm, BUILTIN_CONSTRUCTOR);
265
266 /* make all commands appear as Forth words */
267 SET_FOREACH(cmdp, Xcommand_set) {
268 ficlBuild(bf_sys, (char *)(*cmdp)->c_name, bf_command, FW_DEFAULT);
269 ficlExec(bf_vm, "forth definitions builtins");
270 sprintf(create_buf, "builtin: %s", (*cmdp)->c_name);
271 ficlExec(bf_vm, create_buf);
272 ficlExec(bf_vm, "builtins definitions");
273 }
274 ficlExec(bf_vm, "only forth definitions");
275
276 /* Export some version numbers so that code can detect the loader/host version */
277 ficlSetEnv(bf_sys, "FreeBSD_version", __FreeBSD_version);
278 ficlSetEnv(bf_sys, "loader_version", bootprog_rev);
279
280 /* try to load and run init file if present */
281 if ((fd = open("/boot/boot.4th", O_RDONLY)) != -1) {
282 #ifdef LOADER_VERIEXEC
283 if (verify_file(fd, "/boot/boot.4th", 0, VE_GUESS, __func__) < 0) {
284 close(fd);
285 return;
286 }
287 #endif
288 (void)ficlExecFD(bf_vm, fd);
289 close(fd);
290 }
291 }
292
293 /*
294 * Feed a line of user input to the Forth interpreter
295 */
296 static int
bf_run(const char * line)297 bf_run(const char *line)
298 {
299 int result;
300
301 /*
302 * ficl would require extensive changes to accept a const char *
303 * interface. Instead, cast it away here and hope for the best.
304 * We know at the present time the caller for us in the boot
305 * forth loader can tolerate the string being modified because
306 * the string is passed in here and then not touched again.
307 */
308 result = ficlExec(bf_vm, __DECONST(char *, line));
309
310 DPRINTF("ficlExec '%s' = %d", line, result);
311 switch (result) {
312 case VM_OUTOFTEXT:
313 case VM_ABORTQ:
314 case VM_QUIT:
315 case VM_ERREXIT:
316 break;
317 case VM_USEREXIT:
318 printf("No where to leave to!\n");
319 break;
320 case VM_ABORT:
321 printf("Aborted!\n");
322 break;
323 case BF_PARSE:
324 printf("Parse error!\n");
325 break;
326 default:
327 if (command_errmsg != NULL) {
328 printf("%s\n", command_errmsg);
329 command_errmsg = NULL;
330 }
331 }
332
333 if (result == VM_USEREXIT)
334 panic("interpreter exit");
335 setenv("interpret", bf_vm->state ? "" : "OK", 1);
336
337 return (result);
338 }
339
340 static bool preinit_run = false;
341
342 void
interp_preinit(void)343 interp_preinit(void)
344 {
345 if (preinit_run)
346 return;
347 setenv("script.lang", "forth", 1);
348 bf_init();
349 preinit_run = true;
350 }
351
352 void
interp_init(void)353 interp_init(void)
354 {
355 /* Read our default configuration. */
356 interp_include("/boot/loader.rc");
357 }
358
359 int
interp_run(const char * input)360 interp_run(const char *input)
361 {
362
363 bf_vm->sourceID.i = 0;
364 return bf_run(input);
365 }
366
367 /*
368 * Header prepended to each line. The text immediately follows the header.
369 * We try to make this short in order to save memory -- the loader has
370 * limited memory available, and some of the forth files are very long.
371 */
372 struct includeline
373 {
374 struct includeline *next;
375 char text[0];
376 };
377
378 int
interp_include(const char * filename)379 interp_include(const char *filename)
380 {
381 struct includeline *script, *se, *sp;
382 char input[256]; /* big enough? */
383 int res;
384 char *cp;
385 int prevsrcid, fd, line;
386
387 if (((fd = open(filename, O_RDONLY)) == -1)) {
388 snprintf(command_errbuf, sizeof(command_errbuf),
389 "can't open '%s': %s", filename, strerror(errno));
390 return(CMD_ERROR);
391 }
392
393 #ifdef LOADER_VERIEXEC
394 if (verify_file(fd, filename, 0, VE_GUESS, __func__) < 0) {
395 close(fd);
396 sprintf(command_errbuf,"can't verify '%s'", filename);
397 return(CMD_ERROR);
398 }
399 #endif
400 /*
401 * Read the script into memory.
402 */
403 script = se = NULL;
404 line = 0;
405
406 while (fgetstr(input, sizeof(input), fd) >= 0) {
407 line++;
408 cp = input;
409 /* Allocate script line structure and copy line, flags */
410 if (*cp == '\0')
411 continue; /* ignore empty line, save memory */
412 sp = malloc(sizeof(struct includeline) + strlen(cp) + 1);
413 /* On malloc failure (it happens!), free as much as possible and exit */
414 if (sp == NULL) {
415 while (script != NULL) {
416 se = script;
417 script = script->next;
418 free(se);
419 }
420 snprintf(command_errbuf, sizeof(command_errbuf),
421 "file '%s' line %d: memory allocation failure - aborting",
422 filename, line);
423 close(fd);
424 return (CMD_ERROR);
425 }
426 strcpy(sp->text, cp);
427 sp->next = NULL;
428
429 if (script == NULL) {
430 script = sp;
431 } else {
432 se->next = sp;
433 }
434 se = sp;
435 }
436 close(fd);
437
438 /*
439 * Execute the script
440 */
441 prevsrcid = bf_vm->sourceID.i;
442 bf_vm->sourceID.i = fd;
443 res = CMD_OK;
444 for (sp = script; sp != NULL; sp = sp->next) {
445 res = bf_run(sp->text);
446 if (res != VM_OUTOFTEXT) {
447 snprintf(command_errbuf, sizeof(command_errbuf),
448 "Error while including %s, in the line:\n%s",
449 filename, sp->text);
450 res = CMD_ERROR;
451 break;
452 } else
453 res = CMD_OK;
454 }
455 bf_vm->sourceID.i = prevsrcid;
456
457 while (script != NULL) {
458 se = script;
459 script = script->next;
460 free(se);
461 }
462 return(res);
463 }
464