usr/src/boot/sys/boot/common/interp_forth.c

   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 char 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
  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
 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",
 311                (bootprog_rev[0] - '0') * 10 + (bootprog_rev[2] - '0'));
 312
 313     /* try to load and run init file if present */
 314     if (rc == NULL)
 315         rc = "/boot/forth/boot.4th";
 316     if (*rc != '\0') {
 317         fd = open(rc, O_RDONLY);
 318         if (fd != -1) {
 319             (void)ficlExecFD(bf_vm, fd);
 320             close(fd);
 321         }
 322     }
 323 }
 324
 325 /*
 326  * Feed a line of user input to the Forth interpreter
 327  */
 328 int
 329 bf_run(char *line)
 330 {
 331     int         result;
 332     ficlString s;
 333
 334     FICL_STRING_SET_FROM_CSTRING(s, line);
 335     result = ficlVmExecuteString(bf_vm, s);
 336
 337     DEBUG("ficlExec '%s' = %d", line, result);
 338     switch (result) {
 339     case FICL_VM_STATUS_OUT_OF_TEXT:
 340     case FICL_VM_STATUS_ABORTQ:
 341     case FICL_VM_STATUS_QUIT:
 342     case FICL_VM_STATUS_ERROR_EXIT:
 343         break;
 344     case FICL_VM_STATUS_USER_EXIT:
 345         printf("No where to leave to!\n");
 346         break;
 347     case FICL_VM_STATUS_ABORT:
 348         printf("Aborted!\n");
 349         break;
 350     case BF_PARSE:
 351         printf("Parse error!\n");
 352         break;
 353     default:
 354         if (command_errmsg != NULL) {
 355             printf("%s\n", command_errmsg);
 356             command_errmsg = NULL;
 357         }
 358     }
 359
 360     /* bye is same as reboot and will behave depending on platform */
 361     if (result == FICL_VM_STATUS_USER_EXIT)
 362         bf_run("reboot");
 363     setenv("interpret", bf_vm->state ? "" : "ok", 1);
 364
 365     return (result);
 366 }