/***********************************************************************/
/*                                                                     */
/*                           Objective Caml                            */
/*                                                                     */
/*         Xavier Leroy and Damien Doligez, INRIA Rocquencourt         */
/*                                                                     */
/*  Copyright 1996 Institut National de Recherche en Informatique et   */
/*  en Automatique.  All rights reserved.  This file is distributed    */
/*  under the terms of the GNU Library General Public License.         */
/*                                                                     */
/***********************************************************************/

/* $Id$ */

/* Start-up code */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include "config.h"
#ifdef HAS_UNISTD
#include <unistd.h>
#endif
#ifdef _WIN32
#include <windows.h>
#endif
#include "alloc.h"
#include "callback.h"
#include "custom.h"
#include "debugger.h"
#include "exec.h"
#include "fail.h"
#include "fix_code.h"
#include "gc_ctrl.h"
#include "interp.h"
#include "intext.h"
#include "io.h"
#include "memory.h"
#include "minor_gc.h"
#include "misc.h"
#include "mlvalues.h"
#include "prims.h"
#include "reverse.h"
#include "signals.h"
#include "stacks.h"
#include "sys.h"

#ifndef O_BINARY
#define O_BINARY 0
#endif

#ifndef SEEK_END
#define SEEK_END 2
#endif

header_t atom_table[256];

/* Initialize the atom table */

static void init_atoms(void)
{
  int i;
  for(i = 0; i < 256; i++) atom_table[i] = Make_header(0, i, Caml_white);
}

/* Read the trailer of a bytecode file */

#define FILE_NOT_FOUND (-1)
#define TRUNCATED_FILE (-2)
#define BAD_MAGIC_NUM (-3)

static void fixup_endianness_trailer(uint32 * p)
{
#ifndef ARCH_BIG_ENDIAN
  Reverse_32(p, p);
#endif
}

static int read_trailer(int fd, struct exec_trailer *trail)
{
  lseek(fd, (long) -TRAILER_SIZE, SEEK_END);
  if (read(fd, (char *) trail, TRAILER_SIZE) < TRAILER_SIZE)
    return TRUNCATED_FILE;
  fixup_endianness_trailer(&trail->num_sections);
  if (strncmp(trail->magic, EXEC_MAGIC, 12) == 0)
    return 0;
  else
    return BAD_MAGIC_NUM;
}

static int attempt_open(char **name, struct exec_trailer *trail,
                        int do_open_script)
{
  char * truename;
  int fd;
  int err;
  char buf [2];

  truename = searchpath(*name);
  if (truename == 0) truename = *name; else *name = truename;
  fd = open(truename, O_RDONLY | O_BINARY);
  if (fd == -1) return FILE_NOT_FOUND;
  if (!do_open_script){
    err = read (fd, buf, 2);
    if (err < 2) { close(fd); return TRUNCATED_FILE; }
    if (buf [0] == '#' && buf [1] == '!') { close(fd); return BAD_MAGIC_NUM; }
  }
  err = read_trailer(fd, trail);
  if (err != 0) { close(fd); return err; }
  return fd;
}

/* Read the section descriptors */

static void read_section_descriptors(int fd, struct exec_trailer *trail)
{
  int toc_size, i;

  toc_size = trail->num_sections * 8;
  trail->section = stat_alloc(toc_size);
  lseek(fd, - (long) (TRAILER_SIZE + toc_size), SEEK_END);
  if (read(fd, (char *) trail->section, toc_size) != toc_size)
    fatal_error("Fatal error: cannot read section table\n");
  /* Fixup endianness of lengths */
  for (i = 0; i < trail->num_sections; i++)
    fixup_endianness_trailer(&(trail->section[i].len));
}

/* Position fd at the beginning of the section having the given name.
   Return the length of the section data in bytes. */

static int32 seek_section(int fd, struct exec_trailer *trail, char *name)
{
  long ofs;
  int i;

  ofs = TRAILER_SIZE + trail->num_sections * 8;
  for (i = trail->num_sections - 1; i >= 0; i--) {
    ofs += trail->section[i].len;
    if (strncmp(trail->section[i].name, name, 4) == 0) {
      lseek(fd, -ofs, SEEK_END);
      return trail->section[i].len;
    }
  }
  fatal_error_arg("Fatal_error: section `%s' is missing\n", name);
  return 0; /* not reached */
}

/* Check the primitives used by the bytecode file against the table of
   primitives linked in this interpreter */

static void check_primitives(int fd, int prim_size)
{
  char * prims = stat_alloc(prim_size);
  char * p;
  int idx;

  if (read(fd, prims, prim_size) != prim_size)
    fatal_error("Fatal error: cannot read primitive table\n");
  /* prims contains 0-terminated strings, concatenated. */
  for (p = prims, idx = 0;
       p < prims + prim_size;
       p = p + strlen(p) + 1, idx++) {
    if (names_of_cprim[idx] == NULL ||
        strcmp(p, names_of_cprim[idx]) != 0)
      fatal_error_arg("Fatal error: this bytecode file cannot run "
                      "on this bytecode interpreter\n"
                      "Mismatch on primitive `%s'\n", p);
  }
  stat_free(prims);
}

/* Invocation of ocamlrun: 4 cases.

   1.  runtime + bytecode
       user types:  ocamlrun [options] bytecode args...
       arguments:  ocamlrun [options] bytecode args...

   2.  bytecode script
       user types:  bytecode args...
   2a  (kernel 1) arguments:  ocamlrun ./bytecode args...
   2b  (kernel 2) arguments:  bytecode bytecode args...

   3.  concatenated runtime and bytecode
       user types:  composite args...
       arguments:  composite args...

Algorithm:
  1-  If argument 0 is a valid byte-code file that does not start with #!,
      then we are in case 3 and we pass the same command line to the
      Objective Caml program.
  2-  In all other cases, we parse the command line as:
        (whatever) [options] bytecode args...
      and we strip "(whatever) [options]" from the command line.

*/

/* Configuration parameters and flags */

static unsigned long verbose_init = 0;
static unsigned long percent_free_init = Percent_free_def;
static unsigned long max_percent_free_init = Max_percent_free_def;
static unsigned long minor_heap_init = Minor_heap_def;
static unsigned long heap_chunk_init = Heap_chunk_def;
static unsigned long heap_size_init = Init_heap_def;
static unsigned long max_stack_init = Max_stack_def;
extern int trace_flag;

/* Parse options on the command line */

static int parse_command_line(char **argv)
{
  int i, j;

  for(i = 1; argv[i] != NULL && argv[i][0] == '-'; i++) {
    switch(argv[i][1]) {
#ifdef DEBUG
    case 't':
      trace_flag = 1;
      break;
    case 'P':
      { extern int parser_trace;
        parser_trace = 1;
        break; }
#endif
    case 'v':
      verbose_init = 1+4+8+16+32;
      break;
    case 'p':
      for (j = 0; names_of_cprim[j] != NULL; j++)
        printf("%s\n", names_of_cprim[j]);
      exit(0);
      break;
    default:
      fatal_error_arg("Unknown option %s.\n", argv[i]);
    }
  }
  return i;
}

/* Parse the CAMLRUNPARAM variable */
/* The option letter for each runtime option is the first letter of the
   last word of the ML name of the option (see [stdlib/gc.mli]).
   Except for l (maximum stack size) and h (initial heap size).
*/

static void scanmult (char *opt, long unsigned int *var)
{
  char mult = ' ';
  sscanf (opt, "=%lu%c", var, &mult);
  if (mult == 'k') *var = *var * 1024;
  if (mult == 'M') *var = *var * (1024 * 1024);
  if (mult == 'G') *var = *var * (1024 * 1024 * 1024);
}

static void parse_camlrunparam(void)
{
  char *opt = getenv ("OCAMLRUNPARAM");

  if (opt == NULL) opt = getenv ("CAMLRUNPARAM");

  if (opt != NULL){
    while (*opt != '\0'){
      switch (*opt++){
      case 's': scanmult (opt, &minor_heap_init); break;
      case 'i': scanmult (opt, &heap_chunk_init); break;
      case 'h': scanmult (opt, &heap_size_init); break;
      case 'l': scanmult (opt, &max_stack_init); break;
      case 'o': scanmult (opt, &percent_free_init); break;
      case 'O': scanmult (opt, &max_percent_free_init); break;
      case 'v': scanmult (opt, &verbose_init); break;
      }
    }
  }
}

extern void init_ieee_floats (void);

#ifdef _WIN32
extern DWORD WINAPI caml_signal_thread(LPVOID lpParam);
#endif

/* Main entry point when loading code from a file */

void caml_main(char **argv)
{
  int fd, pos;
  struct exec_trailer trail;
  asize_t prog_size;
  struct channel * chan;
  value res;

  /* Machine-dependent initialization of the floating-point hardware
     so that it behaves as much as possible as specified in IEEE */
  init_ieee_floats();
  init_custom_operations();
  external_raise = NULL;
  /* Determine options and position of bytecode file */
#ifdef DEBUG
  verbose_init = 63;
#endif
  parse_camlrunparam();
  pos = 0;
  fd = attempt_open(&argv[0], &trail, 0);
  if (fd < 0) {
    pos = parse_command_line(argv);
    if (argv[pos] == 0)
      fatal_error("No bytecode file specified.\n");
    fd = attempt_open(&argv[pos], &trail, 1);
    switch(fd) {
    case FILE_NOT_FOUND:
      fatal_error_arg("Fatal error: cannot find file %s\n", argv[pos]);
      break;
    case TRUNCATED_FILE:
    case BAD_MAGIC_NUM:
      fatal_error_arg(
        "Fatal error: the file %s is not a bytecode executable file\n",
        argv[pos]);
      break;
    }
  }
  /* Read the table of contents (section descriptors) */
  read_section_descriptors(fd, &trail);
  /* Initialize the abstract machine */
  init_gc (minor_heap_init, heap_size_init, heap_chunk_init,
           percent_free_init, max_percent_free_init, verbose_init);
  init_stack (max_stack_init);
  init_atoms();
  /* Initialize the interpreter */
  interprete(NULL, 0);
  /* Initialize the debugger, if needed */
  debugger_init();
  /* Load the code */
  code_size = seek_section(fd, &trail, "CODE");
  load_code(fd, code_size);
  /* Check the primitives */
  check_primitives(fd, seek_section(fd, &trail, "PRIM"));
  /* Load the globals */
  seek_section(fd, &trail, "DATA");
  chan = open_descriptor(fd);
  global_data = input_val(chan);
  close_channel(chan); /* this also closes fd */
  stat_free(trail.section);
  /* Ensure that the globals are in the major heap. */
  oldify(global_data, &global_data);
  /* Initialize system libraries */
  init_exceptions();
  sys_init(argv + pos);
#ifdef _WIN32
  /* Start a thread to handle signals */
  if (getenv("CAMLSIGPIPE")) {
    int lpThreadId;
    CreateThread(NULL, 0, caml_signal_thread, NULL, 0, &lpThreadId);
  }
#endif
  /* Execute the program */
  debugger(PROGRAM_START);
  res = interprete(start_code, code_size);
  if (Is_exception_result(res)) {
    exn_bucket = Extract_exception(res);
    extern_sp = &exn_bucket; /* The debugger needs the exception value. */
    debugger(UNCAUGHT_EXC);
    fatal_uncaught_exception(exn_bucket);
  }
}

/* Main entry point when code is linked in as initialized data */

void caml_startup_code(code_t code, asize_t code_size, char *data, char **argv)
{
  value res;

  init_ieee_floats();
#ifdef DEBUG
  verbose_init = 63;
#endif
  parse_camlrunparam();
  external_raise = NULL;
  /* Initialize the abstract machine */
  init_gc (minor_heap_init, heap_size_init, heap_chunk_init,
           percent_free_init, max_percent_free_init, verbose_init);
  init_stack (max_stack_init);
  init_atoms();
  /* Initialize the interpreter */
  interprete(NULL, 0);
  /* Load the code */
  start_code = code;
#ifdef THREADED_CODE
  thread_code(start_code, code_size);
#endif
  /* Load the globals */
  global_data = input_val_from_string((value)data, 0);
  /* Ensure that the globals are in the major heap. */
  oldify(global_data, &global_data);
  /* Run the code */
  init_exceptions();
  sys_init(argv);
  res = interprete(start_code, code_size);
  if (Is_exception_result(res))
    fatal_uncaught_exception(Extract_exception(res));
}