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 DEBUG(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args)
41 #else
42 # define DEBUG(fmt, args...)
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) && !strcmp(name, (*cmdp)->c_name))
89 cmd = (*cmdp)->c_fn;
90 }
91 if (cmd == NULL)
92 panic("callout for unknown command '%s'", name);
93
94 /* Check whether we have been compiled or are being interpreted */
95 if (ficlStackPopInteger(ficlVmGetDataStack(vm))) {
96 /*
97 * Get parameters from stack, in the format:
98 * an un ... a2 u2 a1 u1 n --
99 * Where n is the number of strings, a/u are pairs of
100 * address/size for strings, and they will be concatenated
101 * in LIFO order.
102 */
103 nstrings = ficlStackPopInteger(ficlVmGetDataStack(vm));
104 for (i = 0, len = 0; i < nstrings; i++)
105 len += ficlStackFetch(ficlVmGetDataStack(vm), i * 2).i + 1;
106 line = malloc(strlen(name) + len + 1);
107 strcpy(line, name);
108
109 if (nstrings)
110 for (i = 0; i < nstrings; i++) {
111 len = ficlStackPopInteger(ficlVmGetDataStack(vm));
112 cp = ficlStackPopPointer(ficlVmGetDataStack(vm));
113 strcat(line, " ");
114 strncat(line, cp, len);
115 }
116 } else {
117 /* Get remainder of invocation */
118 tail = ficlVmGetInBuf(vm);
119
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 ficlVmUpdateTib(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\n", 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 ficlVmThrow(vm, result);
157
158 /* This is going to be thrown!!! */
159 ficlStackPushInteger(ficlVmGetDataStack(vm),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(char * rc)254 bf_init(char *rc)
255 {
256 struct bootblk_command **cmdp;
257 char create_buf[41]; /* 31 characters-long builtins */
258 int fd, rv;
259 ficlDictionary *dict;
260 ficlDictionary *env;
261
262 fsi = malloc(sizeof(ficlSystemInformation));
263 ficlSystemInformationInitialize(fsi);
264 fsi->dictionarySize = BF_DICTSIZE;
265
266 bf_sys = ficlSystemCreate(fsi);
267 bf_vm = ficlSystemCreateVm(bf_sys);
268
269 /* Put all private definitions in a "builtins" vocabulary */
270 rv = ficlVmEvaluate(bf_vm, "vocabulary builtins also builtins definitions");
271 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
272 panic("error interpreting forth: %d\n", rv);
273 }
274
275 /* Builtin constructor word */
276 rv = ficlVmEvaluate(bf_vm, BUILTIN_CONSTRUCTOR);
277 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
278 panic("error interpreting forth: %d\n", rv);
279 }
280
281 /* make all commands appear as Forth words */
282 dict = ficlSystemGetDictionary(bf_sys);
283 SET_FOREACH(cmdp, Xcommand_set) {
284 ficlDictionaryAppendPrimitive(dict, (char *)(*cmdp)->c_name,
285 bf_command, FICL_WORD_DEFAULT);
286 rv = ficlVmEvaluate(bf_vm, "forth definitions builtins");
287 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
288 panic("error interpreting forth: %d\n", rv);
289 }
290 sprintf(create_buf, "builtin: %s", (*cmdp)->c_name);
291 rv = ficlVmEvaluate(bf_vm, create_buf);
292 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
293 panic("error interpreting forth: %d\n", rv);
294 }
295 rv = ficlVmEvaluate(bf_vm, "builtins definitions");
296 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
297 panic("error interpreting forth: %d\n", rv);
298 }
299 }
300 rv = ficlVmEvaluate(bf_vm, "only forth definitions");
301 if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
302 panic("error interpreting forth: %d\n", rv);
303 }
304
305 /*
306 * Export some version numbers so that code can detect the loader/host
307 * version
308 */
309 env = ficlSystemGetEnvironment(bf_sys);
310 ficlDictionarySetConstant(env, "loader_version", bootprog_rev);
311
312 /* try to load and run init file if present */
313 if (rc == NULL)
314 rc = "/boot/forth/boot.4th";
315 if (*rc != '\0') {
316 fd = open(rc, O_RDONLY);
317 if (fd != -1) {
318 (void)ficlExecFD(bf_vm, fd);
319 close(fd);
320 }
321 }
322 }
323
324 /*
325 * Feed a line of user input to the Forth interpreter
326 */
327 int
bf_run(char * line)328 bf_run(char *line)
329 {
330 int result;
331 ficlString s;
332
333 FICL_STRING_SET_FROM_CSTRING(s, line);
334 result = ficlVmExecuteString(bf_vm, s);
335
336 DEBUG("ficlExec '%s' = %d", line, result);
337 switch (result) {
338 case FICL_VM_STATUS_OUT_OF_TEXT:
339 case FICL_VM_STATUS_ABORTQ:
340 case FICL_VM_STATUS_QUIT:
341 case FICL_VM_STATUS_ERROR_EXIT:
342 break;
343 case FICL_VM_STATUS_USER_EXIT:
344 printf("No where to leave to!\n");
345 break;
346 case FICL_VM_STATUS_ABORT:
347 printf("Aborted!\n");
348 break;
349 case BF_PARSE:
350 printf("Parse error!\n");
351 break;
352 default:
353 if (command_errmsg != NULL) {
354 printf("%s\n", command_errmsg);
355 command_errmsg = NULL;
356 }
357 }
358
359 /* bye is same as reboot and will behave depending on platform */
360 if (result == FICL_VM_STATUS_USER_EXIT)
361 bf_run("reboot");
362 setenv("interpret", bf_vm->state ? "" : "ok", 1);
363
364 return (result);
365 }
366