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/cdefs.h>
28
29 #include <sys/param.h> /* to pick up __FreeBSD_version */
30 #include <string.h>
31 #include <stand.h>
32 #include "bootstrap.h"
33 #include "ficl.h"
34
35 extern unsigned bootprog_rev;
36
37 /* #define BFORTH_DEBUG */
38
39 #ifdef BFORTH_DEBUG
40 #define DPRINTF(fmt, args...) printf("%s: " fmt "\n", __func__, ## args)
41 #else
42 #define DPRINTF(fmt, args...) ((void)0)
43 #endif
44
45 /*
46 * Eventually, all builtin commands throw codes must be defined
47 * elsewhere, possibly bootstrap.h. For now, just this code, used
48 * just in this file, it is getting defined.
49 */
50 #define BF_PARSE 100
51
52 /*
53 * FreeBSD loader default dictionary cells
54 */
55 #ifndef BF_DICTSIZE
56 #define BF_DICTSIZE 30000
57 #endif
58
59 /*
60 * BootForth Interface to Ficl Forth interpreter.
61 */
62
63 ficlSystemInformation *fsi;
64 ficlSystem *bf_sys;
65 ficlVm *bf_vm;
66
67 /*
68 * Shim for taking commands from BF and passing them out to 'standard'
69 * argv/argc command functions.
70 */
71 static void
bf_command(ficlVm * vm)72 bf_command(ficlVm *vm)
73 {
74 char *name, *line, *tail, *cp;
75 size_t len;
76 struct bootblk_command **cmdp;
77 bootblk_cmd_t *cmd;
78 int nstrings, i;
79 int argc, result;
80 char **argv;
81
82 /* Get the name of the current word */
83 name = vm->runningWord->name;
84
85 /* Find our command structure */
86 cmd = NULL;
87 SET_FOREACH(cmdp, Xcommand_set) {
88 if (((*cmdp)->c_name != NULL) &&
89 strcmp(name, (*cmdp)->c_name) == 0)
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 (ficlStackPopInteger(ficlVmGetDataStack(vm))) {
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 = ficlStackPopInteger(ficlVmGetDataStack(vm));
105 for (i = 0, len = 0; i < nstrings; i++) {
106 ficlStack *stack = ficlVmGetDataStack(vm);
107 len += ficlStackFetch(stack, i * 2).i + 1;
108 }
109 line = malloc(strlen(name) + len + 1);
110 strcpy(line, name);
111
112 if (nstrings)
113 for (i = 0; i < nstrings; i++) {
114 ficlStack *stack = ficlVmGetDataStack(vm);
115
116 len = ficlStackPopInteger(stack);
117 cp = ficlStackPopPointer(stack);
118 strcat(line, " ");
119 strncat(line, cp, len);
120 }
121 } else {
122 /* Get remainder of invocation */
123 tail = ficlVmGetInBuf(vm);
124
125 len = 0;
126 cp = tail;
127 for (; cp != vm->tib.end && *cp != 0 && *cp != '\n'; cp++)
128 len++;
129
130 line = malloc(strlen(name) + len + 2);
131 strcpy(line, name);
132 if (len > 0) {
133 strcat(line, " ");
134 strncat(line, tail, len);
135 ficlVmUpdateTib(vm, tail + len);
136 }
137 }
138 DPRINTF("cmd '%s'", line);
139
140 command_errmsg = command_errbuf;
141 command_errbuf[0] = 0;
142 if (!parse(&argc, &argv, line)) {
143 result = (cmd)(argc, argv);
144 free(argv);
145 } else {
146 result = BF_PARSE;
147 }
148
149 switch (result) {
150 case CMD_CRIT:
151 printf("%s\n", command_errmsg);
152 command_errmsg = NULL;
153 break;
154 case CMD_FATAL:
155 panic("%s", command_errmsg);
156 }
157
158 free(line);
159 /*
160 * If there was error during nested ficlExec(), we may no longer have
161 * valid environment to return. Throw all exceptions from here.
162 */
163 if (result != CMD_OK)
164 ficlVmThrow(vm, result);
165
166 /* This is going to be thrown!!! */
167 ficlStackPushInteger(ficlVmGetDataStack(vm), result);
168 }
169
170 /*
171 * Replace a word definition (a builtin command) with another
172 * one that:
173 *
174 * - Throw error results instead of returning them on the stack
175 * - Pass a flag indicating whether the word was compiled or is
176 * being interpreted.
177 *
178 * There is one major problem with builtins that cannot be overcome
179 * in anyway, except by outlawing it. We want builtins to behave
180 * differently depending on whether they have been compiled or they
181 * are being interpreted. Notice that this is *not* the interpreter's
182 * current state. For example:
183 *
184 * : example ls ; immediate
185 * : problem example ; \ "ls" gets executed while compiling
186 * example \ "ls" gets executed while interpreting
187 *
188 * Notice that, though the current state is different in the two
189 * invocations of "example", in both cases "ls" has been
190 * *compiled in*, which is what we really want.
191 *
192 * The problem arises when you tick the builtin. For example:
193 *
194 * : example-1 ['] ls postpone literal ; immediate
195 * : example-2 example-1 execute ; immediate
196 * : problem example-2 ;
197 * example-2
198 *
199 * We have no way, when we get EXECUTEd, of knowing what our behavior
200 * should be. Thus, our only alternative is to "outlaw" this. See RFI
201 * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related
202 * problem, concerning compile semantics.
203 *
204 * The problem is compounded by the fact that "' builtin CATCH" is valid
205 * and desirable. The only solution is to create an intermediary word.
206 * For example:
207 *
208 * : my-ls ls ;
209 * : example ['] my-ls catch ;
210 *
211 * So, with the below implementation, here is a summary of the behavior
212 * of builtins:
213 *
214 * ls -l \ "interpret" behavior, ie,
215 * \ takes parameters from TIB
216 * : ex-1 s" -l" 1 ls ; \ "compile" behavior, ie,
217 * \ takes parameters from the stack
218 * : ex-2 ['] ls catch ; immediate \ undefined behavior
219 * : ex-3 ['] ls catch ; \ undefined behavior
220 * ex-2 ex-3 \ "interpret" behavior,
221 * \ catch works
222 * : ex-4 ex-2 ; \ "compile" behavior,
223 * \ catch does not work
224 * : ex-5 ex-3 ; immediate \ same as ex-2
225 * : ex-6 ex-3 ; \ same as ex-3
226 * : ex-7 ['] ex-1 catch ; \ "compile" behavior,
227 * \ catch works
228 * : ex-8 postpone ls ; immediate \ same as ex-2
229 * : ex-9 postpone ls ; \ same as ex-3
230 *
231 * As the definition below is particularly tricky, and it's side effects
232 * must be well understood by those playing with it, I'll be heavy on
233 * the comments.
234 *
235 * (if you edit this definition, pay attention to trailing spaces after
236 * each word -- I warned you! :-) )
237 */
238 #define BUILTIN_CONSTRUCTOR \
239 ": builtin: " \
240 ">in @ " /* save the tib index pointer */ \
241 "' " /* get next word's xt */ \
242 "swap >in ! " /* point again to next word */ \
243 "create " /* create a new definition of the next word */ \
244 ", " /* save previous definition's xt */ \
245 "immediate " /* make the new definition an immediate word */ \
246 \
247 "does> " /* Now, the *new* definition will: */ \
248 "state @ if " /* if in compiling state: */ \
249 "1 postpone literal " /* pass 1 flag to indicate compile */ \
250 "@ compile, " /* compile in previous definition */ \
251 "postpone throw " /* throw stack-returned result */ \
252 "else " /* if in interpreting state: */ \
253 "0 swap " /* pass 0 flag to indicate interpret */ \
254 "@ execute " /* call previous definition */ \
255 "throw " /* throw stack-returned result */ \
256 "then ; "
257
258 /*
259 * Initialise the Forth interpreter, create all our commands as words.
260 */
261 void
bf_init(char * rc)262 bf_init(char *rc)
263 {
264 struct bootblk_command **cmdp;
265 char create_buf[41]; /* 31 characters-long builtins */
266 int fd, rv;
267 ficlDictionary *dict;
268 ficlDictionary *env;
269
270 fsi = malloc(sizeof (ficlSystemInformation));
271 ficlSystemInformationInitialize(fsi);
272 fsi->dictionarySize = BF_DICTSIZE;
273
274 bf_sys = ficlSystemCreate(fsi);
275 bf_vm = ficlSystemCreateVm(bf_sys);
276
277 /* Put all private definitions in a "builtins" vocabulary */
278 rv = ficlVmEvaluate(bf_vm,
279 "vocabulary builtins also builtins definitions");
280 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
281 panic("error interpreting forth: %d", rv);
282 }
283
284 /* Builtin constructor word */
285 rv = ficlVmEvaluate(bf_vm, BUILTIN_CONSTRUCTOR);
286 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
287 panic("error interpreting forth: %d", rv);
288 }
289
290 /* make all commands appear as Forth words */
291 dict = ficlSystemGetDictionary(bf_sys);
292 SET_FOREACH(cmdp, Xcommand_set) {
293 ficlDictionaryAppendPrimitive(dict, (char *)(*cmdp)->c_name,
294 bf_command, FICL_WORD_DEFAULT);
295 rv = ficlVmEvaluate(bf_vm, "forth definitions builtins");
296 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
297 panic("error interpreting forth: %d", rv);
298 }
299 sprintf(create_buf, "builtin: %s", (*cmdp)->c_name);
300 rv = ficlVmEvaluate(bf_vm, create_buf);
301 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
302 panic("error interpreting forth: %d", rv);
303 }
304 rv = ficlVmEvaluate(bf_vm, "builtins definitions");
305 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
306 panic("error interpreting forth: %d", rv);
307 }
308 }
309 rv = ficlVmEvaluate(bf_vm, "only forth definitions");
310 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
311 panic("error interpreting forth: %d", rv);
312 }
313
314 /*
315 * Export some version numbers so that code can detect the loader/host
316 * version
317 */
318 env = ficlSystemGetEnvironment(bf_sys);
319 ficlDictionarySetConstant(env, "loader_version", bootprog_rev);
320
321 /* try to load and run init file if present */
322 if (rc == NULL)
323 rc = "/boot/forth/boot.4th";
324 if (*rc != '\0') {
325 fd = open(rc, O_RDONLY);
326 if (fd != -1) {
327 (void) ficlExecFD(bf_vm, fd);
328 close(fd);
329 }
330 }
331 }
332
333 /*
334 * Feed a line of user input to the Forth interpreter
335 */
336 int
bf_run(char * line)337 bf_run(char *line)
338 {
339 int result;
340 ficlString s;
341
342 FICL_STRING_SET_FROM_CSTRING(s, line);
343 result = ficlVmExecuteString(bf_vm, s);
344
345 DPRINTF("ficlExec '%s' = %d", line, result);
346 switch (result) {
347 case FICL_VM_STATUS_OUT_OF_TEXT:
348 case FICL_VM_STATUS_ABORTQ:
349 case FICL_VM_STATUS_QUIT:
350 case FICL_VM_STATUS_ERROR_EXIT:
351 break;
352 case FICL_VM_STATUS_USER_EXIT:
353 printf("No where to leave to!\n");
354 break;
355 case FICL_VM_STATUS_ABORT:
356 printf("Aborted!\n");
357 break;
358 case BF_PARSE:
359 printf("Parse error!\n");
360 break;
361 default:
362 if (command_errmsg != NULL) {
363 printf("%s\n", command_errmsg);
364 command_errmsg = NULL;
365 }
366 }
367
368 /* bye is same as reboot and will behave depending on platform */
369 if (result == FICL_VM_STATUS_USER_EXIT)
370 bf_run("reboot");
371 setenv("interpret", bf_vm->state ? "" : "ok", 1);
372
373 return (result);
374 }
375