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 ficlWord *pInterp;
  67
  68 /*
  69  * Shim for taking commands from BF and passing them out to 'standard'
  70  * argv/argc command functions.
  71  */
  72 static void
  73 bf_command(ficlVm *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 (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             len += ficlStackFetch(ficlVmGetDataStack(vm), 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 = ficlStackPopInteger(ficlVmGetDataStack(vm));
 113                 cp = ficlStackPopPointer(ficlVmGetDataStack(vm));
 114                 strcat(line, " ");
 115                 strncat(line, cp, len);
 116             }
 117     } else {
 118         /* Get remainder of invocation */
 119         tail = ficlVmGetInBuf(vm);
 120
 121         for (cp = tail, len = 0; cp != vm->tib.end && *cp != 0 && *cp != '\n'; cp++, len++)
 122             ;
 123
 124         line = malloc(strlen(name) + len + 2);
 125         strcpy(line, name);
 126         if (len > 0) {
 127             strcat(line, " ");
 128             strncat(line, tail, len);
 129             ficlVmUpdateTib(vm, tail + len);
 130         }
 131     }
 132     DEBUG("cmd '%s'", line);
 133
 134     command_errmsg = command_errbuf;
 135     command_errbuf[0] = 0;
 136     if (!parse(&argc, &argv, line)) {
 137         result = (cmd)(argc, argv);
 138         free(argv);
 139     } else {
 140         result=BF_PARSE;
 141     }
 142
 143     switch (result) {
 144     case CMD_CRIT:
 145         printf("%s\n", command_errmsg);
 146         break;
 147     case CMD_FATAL:
 148         panic("%s\n", command_errmsg);
 149     }
 150
 151     free(line);
 152     /*
 153      * If there was error during nested ficlExec(), we may no longer have
 154      * valid environment to return.  Throw all exceptions from here.
 155      */
 156     if (result != CMD_OK)
 157         ficlVmThrow(vm, result);
 158
 159     /* This is going to be thrown!!! */
 160     ficlStackPushInteger(ficlVmGetDataStack(vm),result);
 161 }
 162
 163 /*
 164  * Replace a word definition (a builtin command) with another
 165  * one that:
 166  *
 167  *        - Throw error results instead of returning them on the stack
 168  *        - Pass a flag indicating whether the word was compiled or is
 169  *          being interpreted.
 170  *
 171  * There is one major problem with builtins that cannot be overcome
 172  * in anyway, except by outlawing it. We want builtins to behave
 173  * differently depending on whether they have been compiled or they
 174  * are being interpreted. Notice that this is *not* the interpreter's
 175  * current state. For example:
 176  *
 177  * : example ls ; immediate
 178  * : problem example ;          \ "ls" gets executed while compiling
 179  * example                      \ "ls" gets executed while interpreting
 180  *
 181  * Notice that, though the current state is different in the two
 182  * invocations of "example", in both cases "ls" has been
 183  * *compiled in*, which is what we really want.
 184  *
 185  * The problem arises when you tick the builtin. For example:
 186  *
 187  * : example-1 ['] ls postpone literal ; immediate
 188  * : example-2 example-1 execute ; immediate
 189  * : problem example-2 ;
 190  * example-2
 191  *
 192  * We have no way, when we get EXECUTEd, of knowing what our behavior
 193  * should be. Thus, our only alternative is to "outlaw" this. See RFI
 194  * 0007, and ANS Forth Standard's appendix D, item 6.7 for a related
 195  * problem, concerning compile semantics.
 196  *
 197  * The problem is compounded by the fact that "' builtin CATCH" is valid
 198  * and desirable. The only solution is to create an intermediary word.
 199  * For example:
 200  *
 201  * : my-ls ls ;
 202  * : example ['] my-ls catch ;
 203  *
 204  * So, with the below implementation, here is a summary of the behavior
 205  * of builtins:
 206  *
 207  * ls -l                                \ "interpret" behavior, ie,
 208  *                                      \ takes parameters from TIB
 209  * : ex-1 s" -l" 1 ls ;                 \ "compile" behavior, ie,
 210  *                                      \ takes parameters from the stack
 211  * : ex-2 ['] ls catch ; immediate      \ undefined behavior
 212  * : ex-3 ['] ls catch ;                \ undefined behavior
 213  * ex-2 ex-3                            \ "interpret" behavior,
 214  *                                      \ catch works
 215  * : ex-4 ex-2 ;                        \ "compile" behavior,
 216  *                                      \ catch does not work
 217  * : ex-5 ex-3 ; immediate              \ same as ex-2
 218  * : ex-6 ex-3 ;                        \ same as ex-3
 219  * : ex-7 ['] ex-1 catch ;              \ "compile" behavior,
 220  *                                      \ catch works
 221  * : ex-8 postpone ls ; immediate       \ same as ex-2
 222  * : ex-9 postpone ls ;                 \ same as ex-3
 223  *
 224  * As the definition below is particularly tricky, and it's side effects
 225  * must be well understood by those playing with it, I'll be heavy on
 226  * the comments.
 227  *
 228  * (if you edit this definition, pay attention to trailing spaces after
 229  *  each word -- I warned you! :-) )
 230  */
 231 #define BUILTIN_CONSTRUCTOR \
 232 ": builtin: "           \
 233   ">in @ "              /* save the tib index pointer */ \
 234   "' "                  /* get next word's xt */ \
 235   "swap >in ! "         /* point again to next word */ \
 236   "create "             /* create a new definition of the next word */ \
 237   ", "                  /* save previous definition's xt */ \
 238   "immediate "          /* make the new definition an immediate word */ \
 239                         \
 240   "does> "              /* Now, the *new* definition will: */ \
 241   "state @ if "         /* if in compiling state: */ \
 242     "1 postpone literal "       /* pass 1 flag to indicate compile */ \
 243     "@ compile, "               /* compile in previous definition */ \
 244     "postpone throw "           /* throw stack-returned result */ \
 245   "else "               /* if in interpreting state: */ \
 246     "0 swap "                   /* pass 0 flag to indicate interpret */ \
 247     "@ execute "                /* call previous definition */ \
 248     "throw "                    /* throw stack-returned result */ \
 249   "then ; "
 250
 251 /*
 252  * Initialise the Forth interpreter, create all our commands as words.
 253  */
 254 void
 255 bf_init(char *rc)
 256 {
 257     struct bootblk_command      **cmdp;
 258     char create_buf[41];        /* 31 characters-long builtins */
 259     int fd, rv;
 260     ficlDictionary *dict;
 261     ficlDictionary *env;
 262
 263     fsi = malloc(sizeof(ficlSystemInformation));
 264     ficlSystemInformationInitialize(fsi);
 265     fsi->dictionarySize = BF_DICTSIZE;
 266
 267     bf_sys = ficlSystemCreate(fsi);
 268     bf_vm = ficlSystemCreateVm(bf_sys);
 269
 270     /* Put all private definitions in a "builtins" vocabulary */
 271     rv = ficlVmEvaluate(bf_vm, "vocabulary builtins also builtins definitions");
 272     if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
 273         panic("error interpreting forth: %d\n", rv);
 274     }
 275
 276     /* Builtin constructor word  */
 277     rv = ficlVmEvaluate(bf_vm, BUILTIN_CONSTRUCTOR);
 278     if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
 279         panic("error interpreting forth: %d\n", rv);
 280     }
 281
 282     /* make all commands appear as Forth words */
 283     dict = ficlSystemGetDictionary(bf_sys);
 284     SET_FOREACH(cmdp, Xcommand_set) {
 285         ficlDictionaryAppendPrimitive(dict, (char *)(*cmdp)->c_name,
 286                 bf_command, FICL_WORD_DEFAULT);
 287         rv = ficlVmEvaluate(bf_vm, "forth definitions builtins");
 288         if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
 289                 panic("error interpreting forth: %d\n", rv);
 290         }
 291         sprintf(create_buf, "builtin: %s", (*cmdp)->c_name);
 292         rv = ficlVmEvaluate(bf_vm, create_buf);
 293         if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
 294                 panic("error interpreting forth: %d\n", rv);
 295         }
 296         rv = ficlVmEvaluate(bf_vm, "builtins definitions");
 297         if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
 298                 panic("error interpreting forth: %d\n", rv);
 299         }
 300     }
 301     rv = ficlVmEvaluate(bf_vm, "only forth definitions");
 302     if (rv != FICL_VM_STATUS_OUT_OF_TEXT) {
 303         panic("error interpreting forth: %d\n", rv);
 304     }
 305
 306     /*
 307      * Export some version numbers so that code can detect the loader/host
 308      * version
 309      */
 310     env = ficlSystemGetEnvironment(bf_sys);
 311     ficlDictionarySetConstant(env, "loader_version",
 312                (bootprog_rev[0] - '0') * 10 + (bootprog_rev[2] - '0'));
 313
 314     pInterp = ficlSystemLookup(bf_sys, "interpret");
 315
 316     /* try to load and run init file if present */
 317     if (rc == NULL)
 318         rc = "/boot/forth/boot.4th";
 319     if (*rc != '\0') {
 320         fd = open(rc, O_RDONLY);
 321         if (fd != -1) {
 322             (void)ficlExecFD(bf_vm, fd);
 323             close(fd);
 324         }
 325     }
 326
 327     /* Do this again, so that interpret can be redefined. */
 328     pInterp = ficlSystemLookup(bf_sys, "interpret");
 329 }
 330
 331 /*
 332  * Feed a line of user input to the Forth interpreter
 333  */
 334 int
 335 bf_run(char *line)
 336 {
 337     int         result;
 338     ficlString s;
 339
 340     FICL_STRING_SET_FROM_CSTRING(s, line);
 341     result = ficlVmExecuteString(bf_vm, s);
 342
 343     DEBUG("ficlExec '%s' = %d", line, result);
 344     switch (result) {
 345     case FICL_VM_STATUS_OUT_OF_TEXT:
 346     case FICL_VM_STATUS_ABORTQ:
 347     case FICL_VM_STATUS_QUIT:
 348     case FICL_VM_STATUS_ERROR_EXIT:
 349         break;
 350     case FICL_VM_STATUS_USER_EXIT:
 351         printf("No where to leave to!\n");
 352         break;
 353     case FICL_VM_STATUS_ABORT:
 354         printf("Aborted!\n");
 355         break;
 356     case BF_PARSE:
 357         printf("Parse error!\n");
 358         break;
 359     default:
 360         /* Hopefully, all other codes filled this buffer */
 361         printf("%s\n", command_errmsg);
 362     }
 363
 364     /* bye is same as reboot and will behave depending on platform */
 365     if (result == FICL_VM_STATUS_USER_EXIT)
 366         bf_run("reboot");
 367     setenv("interpret", bf_vm->state ? "" : "ok", 1);
 368
 369     return result;
 370 }