/* Basic system calls */

#include <errno.h>
#include <sys/types.h>
#include <fcntl.h>
#include <signal.h>
#include "config.h"
#include "alloc.h"
#include "fail.h"
#include "globals.h"
#include "instruct.h"
#include "mlvalues.h"
#include "signals.h"
#include "stacks.h"
#include "io.h"

#ifdef HAS_STRERROR

extern char * strerror();

char * error_message()
{
  return strerror(errno);
}

#else

extern int sys_nerr;
extern char * sys_errlist [];

char * error_message()
{
  if (errno < 0 || errno >= sys_nerr)
    return "unknown error";
  else
    return sys_errlist[errno];
}

#endif /* HAS_STRERROR */

void sys_error(arg)
     char * arg;
{
  char * err = error_message();
  value exnarg;

  /* Raise SysErr with argument (err, SOME errno) */

  Push_roots(r, 2);
  r[0] = copy_string(err);	/* The error message string	*/

  r[1] = alloc(1, SOMEtag);	/* The SOME errno object	*/
  Field(r[1], 0) = Val_long(errno);

  exnarg = alloc_tuple(2);	/* The argument tuple		*/
  Field(exnarg, 0) = r[0];
  Field(exnarg, 1) = r[1];
  Pop_roots();

  raise_with_arg(SYS_ERROR_EXN, exnarg);
}

void sys_exit(retcode)          /* ML */
     value retcode;
{
  flush_stdouterr();
  exit(Int_val(retcode));
}

#ifndef O_BINARY
#define O_BINARY 0
#endif
#ifndef O_TEXT
#define O_TEXT 0
#endif

static int sys_open_flags[] = {
  O_RDONLY, O_WRONLY, O_RDWR, O_APPEND, O_CREAT, O_TRUNC, O_EXCL,
  O_BINARY, O_TEXT
};
#ifdef macintosh
static int sys_text_flags []  = { 0, 0, 0, 0, 0, 0, 0, 0, 1 };
static int sys_write_flags [] = { 0, 1, 1, 0, 0, 0, 0, 0, 0 };
#endif

value sys_open(path, flags, perm) /* ML */
     value path, flags, perm;
{
  int ret;
#ifdef macintosh
  extern void set_file_type (char *name, long type);
#if defined(THINK_C) || defined(__MWERKS__)
# define FILE_NAME_SIZE 256
  char filename_temp[FILE_NAME_SIZE];
  char *expanded;
  extern char *unix_to_mac_filename(char *, char *, int);
  expanded = unix_to_mac_filename(String_val(path), filename_temp, FILE_NAME_SIZE);
  if (expanded == NULL)
    ret = -1;
  else
    ret = open(expanded, convert_flag_list(flags, sys_open_flags));
  if ( ret != -1 && convert_flag_list (flags, sys_text_flags)
  	             && convert_flag_list (flags, sys_write_flags))
    set_file_type (expanded, 'TEXT');
#else
  ret = open(String_val(path), convert_flag_list(flags, sys_open_flags));
  if (ret != -1 && convert_flag_list (flags, sys_text_flags))
    set_file_type (String_val (path), 'TEXT');
#endif
#else
  ret = open(String_val(path), convert_flag_list(flags, sys_open_flags),
             Int_val(perm));
#endif
  if (ret == -1) sys_error(String_val(path));
  return Val_long(ret);
}

value sys_close(fd)             /* ML */
     value fd;
{
  if (close(Int_val(fd)) != 0) sys_error(NULL);
  return Atom(0);
}

value sys_remove(name)          /* ML */
     value name;
{
  int ret;
  ret = unlink(String_val(name));
  if (ret != 0) sys_error(String_val(name));
  return Atom(0);
}

value sys_rename(oldname, newname) /* ML */
     value oldname, newname;
{
#ifdef HAS_RENAME
  if (rename(String_val(oldname), String_val(newname)) != 0) 
    sys_error(String_val(oldname));
#else
  invalid_argument("rename: not implemented");
#endif
  return Atom(0);
}

value sys_chdir(dirname)        /* ML */
     value dirname;
{
  if (chdir(String_val(dirname)) != 0) sys_error(String_val(dirname));
  return Atom(0);
}

extern char * getenv();

value sys_getenv(var)           /* ML */
     value var;
{
  char * res;

  res = getenv(String_val(var));
  if (res == 0) {
    mlraise(Atom(NOT_FOUND_EXN));
  }
  return copy_string(res);
}

value sys_system_command(command)   /* ML */
     value command;
{
  int retcode = system(String_val(command));
  if (retcode == -1) sys_error(String_val(command));
  return Val_int(retcode);
}

static int sys_var_init[] = {
  0400, 0200, 0100,
  0040, 0020, 0010,
  0004, 0002, 0001,
  04000, 02000,
  0444, 0222, 0111
};

void sys_init(argv)
     char ** argv;
{
  value v;
  int i;

  #ifndef MSDOS
  void init_float_handler();
  init_float_handler();
  #endif

  v = copy_string_array(argv);
  modify(&Field(global_data, SYS__COMMAND_LINE), v);
  for (i = SYS__S_IRUSR; i <= SYS__S_IXALL; i++)
    Field(global_data, i) = Val_long(sys_var_init[i - SYS__S_IRUSR]);
  Field(global_data, SYS__INTERACTIVE) = Val_false;
  Field(global_data, SYS__MAX_VECT_LENGTH) = Val_long(Max_wosize);
  Field(global_data, SYS__MAX_STRING_LENGTH) =
    Val_long(Max_wosize * sizeof(value) - 2);
}

/* Handling of user interrupts and floating-point errors */

#ifndef MSDOS

unsigned char raise_break_exn[] = { ATOM, BREAK_EXN, RAISE };

sighandler_return_type intr_handler(sig)
     int sig;
{
#ifndef BSD_SIGNALS
  signal (SIGINT, intr_handler);
#endif
  signal_handler = raise_break_exn;
  signal_number = 0;
  execute_signal();
}

value sys_catch_break(onoff)    /* ML */
     value onoff;
{
  if (Tag_val(onoff))
    signal(SIGINT, intr_handler);
  else
    signal(SIGINT, SIG_DFL);
  return Atom(0);
}

sighandler_return_type float_handler(sig)
     int sig;
{
#ifndef BSD_SIGNALS
  signal (SIGFPE, float_handler);
#endif
  if (float_exn == FAILURE_EXN)
    failwith("floating point error");
  else
    mlraise(Atom(float_exn));
}

void init_float_handler()
{
  signal(SIGFPE, float_handler);
}
#endif

/* Search path function */

#ifndef MSDOS
#ifndef macintosh

char * searchpath(name)
     char * name;
{
  static char fullname[512];
  char * path;
  char * p;
  char * q;

  for (p = name; *p != 0; p++) {
    if (*p == '/') return name;
  }
  path = getenv("PATH");
  if (path == 0) return 0;
  while(1) {
    p = fullname;
    while (*path != 0 && *path != ':') {
      *p++ = *path++;
    }
    if (p != fullname) *p++ = '/';
    q = name;
    while (*q != 0) {
      *p++ = *q++;
    }
    *p = 0;
    if (access(fullname, 1) == 0) return fullname;
    if (*path == 0) return 0;
    path++;
  }
}

#endif
#endif