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