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 __FBSDID("$FreeBSD: src/sys/boot/common/interp_forth.c,v 1.23 2003/08/25 23:30:41 obrien Exp $");
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 char bootprog_rev[];
37
38 /* #define BFORTH_DEBUG */
39
40 #ifdef BFORTH_DEBUG
41 # define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args)
42 #else
43 # define DEBUG(fmt, args...)
44 #endif
45
46 /*
47 * Eventually, all builtin commands throw codes must be defined
48 * elsewhere, possibly bootstrap.h. For now, just this code, used
49 * just in this file, it is getting defined.
50 */
51 #define BF_PARSE 100
52
53 /*
54 * BootForth Interface to Ficl Forth interpreter.
55 */
56
57 FICL_SYSTEM *bf_sys;
58 FICL_VM *bf_vm;
59 FICL_WORD *pInterp;
60
61 /*
62 * Shim for taking commands from BF and passing them out to 'standard'
63 * argv/argc command functions.
64 */
65 static void
66 bf_command(FICL_VM *vm)
67 {
68 char *name, *line, *tail, *cp;
69 size_t len;
70 struct bootblk_command **cmdp;
71 bootblk_cmd_t *cmd;
72 int nstrings, i;
73 int argc, result;
74 char **argv;
75
76 /* Get the name of the current word */
77 name = vm->runningWord->name;
78
79 /* Find our command structure */
80 cmd = NULL;
81 SET_FOREACH(cmdp, Xcommand_set) {
82 if (((*cmdp)->c_name != NULL) && !strcmp(name, (*cmdp)->c_name))
83 cmd = (*cmdp)->c_fn;
84 }
85 if (cmd == NULL)
86 panic("callout for unknown command '%s'", name);
87
88 /* Check whether we have been compiled or are being interpreted */
89 if (stackPopINT(vm->pStack)) {
90 /*
91 * Get parameters from stack, in the format:
92 * an un ... a2 u2 a1 u1 n --
93 * Where n is the number of strings, a/u are pairs of
94 * address/size for strings, and they will be concatenated
95 * in LIFO order.
96 */
97 nstrings = stackPopINT(vm->pStack);
98 for (i = 0, len = 0; i < nstrings; i++)
99 len += stackFetch(vm->pStack, i * 2).i + 1;
100 line = malloc(strlen(name) + len + 1);
101 strcpy(line, name);
102
103 if (nstrings)
104 for (i = 0; i < nstrings; i++) {
105 len = stackPopINT(vm->pStack);
106 cp = stackPopPtr(vm->pStack);
107 strcat(line, " ");
108 strncat(line, cp, len);
109 }
110 } else {
111 /* Get remainder of invocation */
112 tail = vmGetInBuf(vm);
113 for (cp = tail, len = 0; cp != vm->tib.end && *cp != 0 && *cp != '\n'; cp++, len++)
114 ;
115
116 line = malloc(strlen(name) + len + 2);
117 strcpy(line, name);
118 if (len > 0) {
119 strcat(line, " ");
120 strncat(line, tail, len);
121 vmUpdateTib(vm, tail + len);
122 }
123 }
124 DEBUG("cmd '%s'", line);
125
126 command_errmsg = command_errbuf;
127 command_errbuf[0] = 0;
128 if (!parse(&argc, &argv, line)) {
129 result = (cmd)(argc, argv);
130 free(argv);
131 } else {
132 result=BF_PARSE;
133 }
134 free(line);
135 /* This is going to be thrown!!! */
136 stackPushINT(vm->pStack,result);
137 }
138
139 /*
140 * Replace a word definition (a builtin command) with another
141 * one that:
142 *
143 * - Throw error results instead of returning them on the stack
144 * - Pass a flag indicating whether the word was compiled or is
145 * being interpreted.
146 *
147 * There is one major problem with builtins that cannot be overcome
148 * in anyway, except by outlawing it. We want builtins to behave
149 * differently depending on whether they have been compiled or they
150 * are being interpreted. Notice that this is *not* the interpreter's
151 * current state. For example:
152 *
153 * : example ls ; immediate
154 * : problem example ; \ "ls" gets executed while compiling
155 * example \ "ls" gets executed while interpreting
156 *
157 * Notice that, though the current state is different in the two
158 * invocations of "example", in both cases "ls" has been
159 * *compiled in*, which is what we really want.
160 *
161 * The problem arises when you tick the builtin. For example:
162 *
163 * : example-1 ['] ls postpone literal ; immediate
164 * : example-2 example-1 execute ; immediate
165 * : problem example-2 ;
166 * example-2
167 *
168 * We have no way, when we get EXECUTEd, of knowing what our behavior
169 * should be. Thus, our only alternative is to "outlaw" this. See RFI
170 * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related
171 * problem, concerning compile semantics.
172 *
173 * The problem is compounded by the fact that "' builtin CATCH" is valid
174 * and desirable. The only solution is to create an intermediary word.
175 * For example:
176 *
177 * : my-ls ls ;
178 * : example ['] my-ls catch ;
179 *
180 * So, with the below implementation, here is a summary of the behavior
181 * of builtins:
182 *
183 * ls -l \ "interpret" behavior, ie,
184 * \ takes parameters from TIB
185 * : ex-1 s" -l" 1 ls ; \ "compile" behavior, ie,
186 * \ takes parameters from the stack
187 * : ex-2 ['] ls catch ; immediate \ undefined behavior
188 * : ex-3 ['] ls catch ; \ undefined behavior
189 * ex-2 ex-3 \ "interpret" behavior,
190 * \ catch works
191 * : ex-4 ex-2 ; \ "compile" behavior,
192 * \ catch does not work
193 * : ex-5 ex-3 ; immediate \ same as ex-2
194 * : ex-6 ex-3 ; \ same as ex-3
195 * : ex-7 ['] ex-1 catch ; \ "compile" behavior,
196 * \ catch works
197 * : ex-8 postpone ls ; immediate \ same as ex-2
198 * : ex-9 postpone ls ; \ same as ex-3
199 *
200 * As the definition below is particularly tricky, and it's side effects
201 * must be well understood by those playing with it, I'll be heavy on
202 * the comments.
203 *
204 * (if you edit this definition, pay attention to trailing spaces after
205 * each word -- I warned you! :-) )
206 */
207 #define BUILTIN_CONSTRUCTOR \
208 ": builtin: " \
209 ">in @ " /* save the tib index pointer */ \
210 "' " /* get next word's xt */ \
211 "swap >in ! " /* point again to next word */ \
212 "create " /* create a new definition of the next word */ \
213 ", " /* save previous definition's xt */ \
214 "immediate " /* make the new definition an immediate word */ \
215 \
216 "does> " /* Now, the *new* definition will: */ \
217 "state @ if " /* if in compiling state: */ \
218 "1 postpone literal " /* pass 1 flag to indicate compile */ \
219 "@ compile, " /* compile in previous definition */ \
220 "postpone throw " /* throw stack-returned result */ \
221 "else " /* if in interpreting state: */ \
222 "0 swap " /* pass 0 flag to indicate interpret */ \
223 "@ execute " /* call previous definition */ \
224 "throw " /* throw stack-returned result */ \
225 "then ; "
226
227 /*
228 * Initialise the Forth interpreter, create all our commands as words.
229 */
230 void
231 bf_init(void)
232 {
233 struct bootblk_command **cmdp;
234 char create_buf[41]; /* 31 characters-long builtins */
235 int fd;
236
237 bf_sys = ficlInitSystem(10000); /* Default dictionary ~4000 cells */
238 bf_vm = ficlNewVM(bf_sys);
239
240 /* Put all private definitions in a "builtins" vocabulary */
241 ficlExec(bf_vm, "vocabulary builtins also builtins definitions");
242
243 /* Builtin constructor word */
244 ficlExec(bf_vm, BUILTIN_CONSTRUCTOR);
245
246 /* make all commands appear as Forth words */
247 SET_FOREACH(cmdp, Xcommand_set) {
248 ficlBuild(bf_sys, (char *)(*cmdp)->c_name, bf_command, FW_DEFAULT);
249 ficlExec(bf_vm, "forth definitions builtins");
250 sprintf(create_buf, "builtin: %s", (*cmdp)->c_name);
251 ficlExec(bf_vm, create_buf);
252 ficlExec(bf_vm, "builtins definitions");
253 }
254 ficlExec(bf_vm, "only forth definitions");
255
256 /* Export some version numbers so that code can detect the loader/host version */
257 ficlSetEnv(bf_sys, "FreeBSD_version", __FreeBSD_version);
258 ficlSetEnv(bf_sys, "loader_version",
259 (bootprog_rev[0] - '') * 10 + (bootprog_rev[2] - ''));
260
261 /* try to load and run init file if present */
262 if ((fd = open("/boot/boot.4th", O_RDONLY)) != -1) {
263 (void)ficlExecFD(bf_vm, fd);
264 close(fd);
265 }
266
267 /* Do this last, so /boot/boot.4th can change it */
268 pInterp = ficlLookup(bf_sys, "interpret");
269 }
270
271 /*
272 * Feed a line of user input to the Forth interpreter
273 */
274 int
275 bf_run(char *line)
276 {
277 int result;
278
279 result = ficlExec(bf_vm, line);
280
281 DEBUG("ficlExec '%s' = %d", line, result);
282 switch (result) {
283 case VM_OUTOFTEXT:
284 case VM_ABORTQ:
285 case VM_QUIT:
286 case VM_ERREXIT:
287 break;
288 case VM_USEREXIT:
289 printf("No where to leave to!\n");
290 break;
291 case VM_ABORT:
292 printf("Aborted!\n");
293 break;
294 case BF_PARSE:
295 printf("Parse error!\n");
296 break;
297 default:
298 /* Hopefully, all other codes filled this buffer */
299 printf("%s\n", command_errmsg);
300 }
301
302 if (result == VM_USEREXIT)
303 panic("interpreter exit");
304 setenv("interpret", bf_vm->state ? "" : "OK", 1);
305
306 return result;
307 }
308 Cache object: 91081bc90de0c39f9048137b6ff63134
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