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Line 85... Line 85...
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  unsigned char flags; /* command.com flags, as defined in rmodinit.h */
 85 
  unsigned char flags; /* command.com flags, as defined in rmodinit.h */
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  char *execcmd;
 86 
  char *execcmd;
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  unsigned short envsiz;
 87 
  unsigned short envsiz;
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};
 88 
};
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- 
 
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/* max length of the cmdline storage (bytes) - includes also max length of
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 * line loaded from a BAT file (no more than 255 bytes!) */
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#define CMDLINE_MAXLEN 255
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/* sets guard values at a few places in memory for later detection of
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 * overflows via memguard_check() */
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static void memguard_set(void) {
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  BUFFER[sizeof(BUFFER) - 1] = 0xC7;
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  BUFFER[sizeof(BUFFER) - (CMDLINE_MAXLEN + 3)] = 0xC7;
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}
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/* checks for valguards at specific memory locations, returns 0 on success */
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static int memguard_check(unsigned short rmodseg) {
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  /* check RMOD signature (would be overwritten in case of stack overflow */
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  static char msg[] = "!! MEMORY CORRUPTION ## DETECTED !!";
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  unsigned short far *rmodsig = MK_FP(rmodseg, 0x100 + 6);
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  if (*rmodsig != 0x2019) {
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    msg[22] = '1';
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    outputnl(msg);
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    printf("rmodseg = %04X ; *rmodsig = %04X\r\n", rmodseg, *rmodsig);
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    return(1);
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  }
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  /* check last BUFFER byte (could be overwritten by cmdline) */
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  if (BUFFER[sizeof(BUFFER) - 1] != 0xC7) {
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    msg[22] = '2';
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    outputnl(msg);
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    return(2);
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  }
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  /* check that cmdline BUFFER's end hasn't been touched by something else */
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  if (BUFFER[sizeof(BUFFER) - (CMDLINE_MAXLEN + 3)] != 0xC7) {
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    msg[22] = '3';
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    outputnl(msg);
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    return(3);
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  }
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  /* all good */
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  return(0);
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}
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/* parses command line the hard way (directly from PSP) */
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/* parses command line the hard way (directly from PSP) */
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static void parse_argv(struct config *cfg) {
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static void parse_argv(struct config *cfg) {
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  unsigned short i;
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  unsigned short i;
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  const unsigned char *cmdlinelen = (unsigned char *)0x80;
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  const unsigned char *cmdlinelen = (unsigned char *)0x80;
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  rmod->batnextline = 0;
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  rmod->batnextline = 0;
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  return(-1);
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  return(-1);
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}
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}
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/* max length of the cmdline storage (bytes) - includes also max length of
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 * line loaded from a BAT file (no more than 255 bytes!) */
 - 
 
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#define CMDLINE_MAXLEN 255
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 - 
 
614 
int main(void) {
 650 
int main(void) {
615 
  static struct config cfg;
 651 
  static struct config cfg;
616 
  static unsigned short far *rmod_envseg;
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  static unsigned short far *rmod_envseg;
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  static unsigned short far *lastexitcode;
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  static unsigned short far *lastexitcode;
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  static struct rmod_props far *rmod;
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  static struct rmod_props far *rmod;
Line 636... Line 672...
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     * die asap, because the command has been executed already, so I no longer
672 
     * die asap, because the command has been executed already, so I no longer
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     * have a purpose in life */
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     * have a purpose in life */
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    if (rmod->flags & FLAG_EXEC_AND_QUIT) sayonara(rmod);
 674 
    if (rmod->flags & FLAG_EXEC_AND_QUIT) sayonara(rmod);
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  }
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  }
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 676 
 
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  /* install a few guardvals in memory to detect some cases of overflows */
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 678 
  memguard_set();
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641 
  rmod_envseg = MK_FP(rmod->rmodseg, RMOD_OFFSET_ENVSEG);
 680 
  rmod_envseg = MK_FP(rmod->rmodseg, RMOD_OFFSET_ENVSEG);
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  lastexitcode = MK_FP(rmod->rmodseg, RMOD_OFFSET_LEXITCODE);
 681 
  lastexitcode = MK_FP(rmod->rmodseg, RMOD_OFFSET_LEXITCODE);
643 
 
 682 
 
644 
  /* make COMPSEC point to myself */
 683 
  /* make COMPSEC point to myself */
645 
  set_comspec_to_self(*rmod_envseg);
 684 
  set_comspec_to_self(*rmod_envseg);
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664 
    SKIP_NEWLINE:
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    SKIP_NEWLINE:
665 
 
 704 
 
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    /* cancel any redirections that may have been set up before */
 705 
    /* cancel any redirections that may have been set up before */
667 
    redir_revert();
 706 
    redir_revert();
668 
 
 707 
 
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    /* memory check */
- 
 
 709 
    memguard_check(rmod->rmodseg);
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 710 
 
669 
    /* preset cmdline to point at the end of my general-purpose buffer */
 711 
    /* preset cmdline to point at the end of my general-purpose buffer (with
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 712 
     * one extra byte for the NULL terminator and another for memguard val) */
670 
    cmdline = BUFFER + sizeof(BUFFER) - (CMDLINE_MAXLEN + 1);
 713 
    cmdline = BUFFER + sizeof(BUFFER) - (CMDLINE_MAXLEN + 2);
671 
 
 714 
 
672 
    /* (re)load translation strings if needed */
 715 
    /* (re)load translation strings if needed */
673 
    nls_langreload(BUFFER, *rmod_envseg);
 716 
    nls_langreload(BUFFER, *rmod_envseg);
674 
 
 717 
 
675 
    /* skip user input if I have a command to exec (/C or /K) */
 718 
    /* skip user input if I have a command to exec (/C or /K) */