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352 mateuszvis 1
/* entry point for internal commands
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 * matches internal commands and executes them
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 * returns -1 or exit code if processed
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 * returns -2 if command unrecognized */
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#include <i86.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "doserr.h"
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#include "env.h"
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#include "helpers.h"
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struct cmd_funcparam {
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  int argc;                 /* number of arguments */
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  const char *argv[256];    /* pointers to each argument */
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  unsigned short env_seg;   /* segment of environment block */
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  unsigned short argoffset; /* offset of cmdline where first argument starts */
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  const char far *cmdline;  /* original cmdline (terminated by \r) */
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  char BUFFER[1024];        /* a buffer for whatever is needed */
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};
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#include "cmd/cd.c"
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#include "cmd/dir.c"
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#include "cmd/exit.c"
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#include "cmd/path.c"
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#include "cmd/prompt.c"
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#include "cmd/set.c"
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#include "cmd/ver.c"
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#include "cmd.h"
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struct CMD_ID {
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  const char *cmd;
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  int (*func_ptr)(struct cmd_funcparam *); /* pointer to handling function */
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};
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const struct CMD_ID INTERNAL_CMDS[] = {
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  {"CD",      cmd_cd},
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  {"CHDIR",   cmd_cd},
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  {"DIR",     cmd_dir},
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  {"EXIT",    cmd_exit},
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  {"PATH",    cmd_path},
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  {"PROMPT",  cmd_prompt},
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  {"SET",     cmd_set},
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  {"VER",     cmd_ver},
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  {NULL,      NULL}
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};
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/* NULL if cmdline is not matching an internal command, otherwise returns a
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 * pointer to a CMD_ID struct */
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static const struct CMD_ID *cmd_match(const char far *cmdline, unsigned short *argoffset) {
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  unsigned short i;
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  char buff[10];
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  /* copy command to buffer, until space, NULL, tab, return, dot, slash or backslash */
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  for (i = 0; i < 9; i++) {
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    if (cmdline[i] == ' ') break;
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    if (cmdline[i] == 0) break;
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    if (cmdline[i] == '\t') break;
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    if (cmdline[i] == '\r') break;
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    if (cmdline[i] == '.') break;
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    if (cmdline[i] == '/') break;
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    if (cmdline[i] == '\\') break;
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    buff[i] = cmdline[i];
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  }
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  buff[i] = 0;
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  /* advance to nearest non-space to find where arguments start */
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  while (cmdline[i] == ' ') i++;
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  *argoffset = i;
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  /* try matching an internal command */
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  for (i = 0; INTERNAL_CMDS[i].cmd != NULL; i++) {
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    /*printf("imatch(%s,%s)\r\n", buff, INTERNAL_CMDS[i].cmd); */
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    if (imatch(buff, INTERNAL_CMDS[i].cmd)) {
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      /*printf("match cmd i=%u (buff=%s)\r\n", i, buff);*/
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      return(&(INTERNAL_CMDS[i]));
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    }
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  }
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  return(NULL); /* command is not recognized as internal */
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}
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/* explodes a command into an array of arguments where last arg is NULL
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 * returns number of args */
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unsigned short cmd_explode(char *buff, const char far *s, char const **argvlist) {
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  int si = 0, argc = 0, i = 0;
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  for (;;) {
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    /* skip to next non-space character */
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    while (s[si] == ' ') si++;
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    /* end of string? */
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    if (s[si] == 0) break;
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    /* set argv ptr */
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    argvlist[argc++] = buff + i;
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    /* find next space while copying arg to local buffer */
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    do {
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      buff[i++] = s[si++];
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    } while (s[si] != ' ' && s[si] != 0 && s[si] != '/');
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    buff[i++] = 0;
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    /* is this end of string? */
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    if (s[si] == 0) break;
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  }
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  argvlist[argc] = NULL;
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  return(argc);
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}
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int cmd_process(unsigned short env_seg, const char far *cmdline, char *BUFFER) {
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  const struct CMD_ID *cmdptr;
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  unsigned short argoffset;
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  struct cmd_funcparam *p = (void *)BUFFER;
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  /* special case: is this a drive change? (like "E:") */
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  if ((cmdline[0] != 0) && (cmdline[1] == ':') && ((cmdline[2] == ' ') || (cmdline[2] == 0))) {
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    if (((cmdline[0] >= 'a') && (cmdline[0] <= 'z')) || ((cmdline[0] >= 'A') && (cmdline[0] <= 'Z'))) {
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      unsigned char drive = cmdline[0];
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      unsigned char curdrive = 0;
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      if (drive >= 'a') {
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        drive -= 'a';
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      } else {
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        drive -= 'A';
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      }
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      _asm {
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        push ax
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        push dx
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        mov ah, 0x0e     /* DOS 1+ - SELECT DEFAULT DRIVE */
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        mov dl, drive    /* DL = new default drive (00h = A:, 01h = B:, etc) */
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        int 0x21
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        mov ah, 0x19     /* DOS 1+ - GET CURRENT DRIVE */
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        int 0x21
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        mov curdrive, al /* cur drive (0=A, 1=B, etc) */
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        pop dx
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        pop ax
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      }
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      if (curdrive != drive) puts(doserr(0x0f));
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      return(-1);
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    }
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  }
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  /* try matching an internal command */
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  cmdptr = cmd_match(cmdline, &argoffset);
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  if (cmdptr == NULL) return(-2); /* command is not recognized as internal */
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  /* printf("recognized internal command: '%s', tail of command at offset %u\r\n", cmdptr->cmd, argoffset); */
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  /* prepare function parameters and feed it to the cmd handling function */
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  p->argc = cmd_explode(BUFFER + sizeof(*p), cmdline + argoffset, p->argv);
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  p->env_seg = env_seg;
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  p->argoffset = argoffset;
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  p->cmdline = cmdline;
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  return((cmdptr->func_ptr)(p));
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}