WebSVN – SvarDOS – Diff – /svarcom/tags/svarcom-2023.1/command.c


/* This file is part of the SvarCOM project and is published under the terms
 * of the MIT license.
 *
 * Copyright (C) 2021 Mateusz Viste
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */
 
/*
 * SvarCOM is a command-line interpreter.
 *
 * a little memory area is allocated as high as possible. it contains:
 *  - a signature (like XMS drivers do)
 *  - a routine for exec'ing programs
 *  - a "last command" buffer for input history
 *
 * when svarcom starts, it tries locating the routine in memory.
 *
 * if found:
 *   waits for user input and processes it. if execing something is required, set the "next exec" field in routine's memory and quit.
 *
 * if not found:
 *   installs it by creating a new PSP, set int 22 vector to the routine, set my "parent PSP" to the routine
 *   and quit.
 *
 * PSP structure
 * http://www.piclist.com/techref/dos/psps.htm
 *
 *
 *
 * === MCB ===
 *
 * each time that DOS allocates memory, it prefixes the allocated memory with
 * a 16-bytes structure called a "Memory Control Block" (MCB). This control
 * block has the following structure:
 *
 * Offset  Size     Description
 *   00h   byte     'M' =  non-last member of the MCB chain
 *                  'Z' = indicates last entry in MCB chain
 *                  other values cause "Memory Allocation Failure" on exit
 *   01h   word     PSP segment address of the owner (Process Id)
 *                  possible values:
 *                    0 = free
 *                    8 = Allocated by DOS before first user pgm loaded
 *                    other = Process Id/PSP segment address of owner
 *   03h  word      number of paragraphs related to this MCB (excluding MCB)
 *   05h  11 bytes  reserved
 *   10h  ...       start of actual allocated memory block
 */
 
#include <i86.h>
#include <dos.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#include <process.h>
 
#include "cmd.h"
#include "env.h"
#include "helpers.h"
#include "redir.h"
#include "rmodinit.h"
#include "sayonara.h"
 
#include "rmodcore.h" /* rmod binary inside a BUFFER array */
 
struct config {
  unsigned char flags; /* command.com flags, as defined in rmodinit.h */
  char *execcmd;
  unsigned short envsiz;
};
 
/* max length of the cmdline storage (bytes) - includes also max length of
 * line loaded from a BAT file (no more than 255 bytes!) */
#define CMDLINE_MAXLEN 255
 
 
/* sets guard values at a few places in memory for later detection of
 * overflows via memguard_check() */
static void memguard_set(void) {
  BUFFER[sizeof(BUFFER) - 1] = 0xC7;
  BUFFER[sizeof(BUFFER) - (CMDLINE_MAXLEN + 3)] = 0xC7;
}
 
 
/* checks for valguards at specific memory locations, returns 0 on success */
static int memguard_check(unsigned short rmodseg) {
  /* check RMOD signature (would be overwritten in case of stack overflow */
  static char msg[] = "!! MEMORY CORRUPTION ## DETECTED !!";
  unsigned short far *rmodsig = MK_FP(rmodseg, 0x100 + 6);
  if (*rmodsig != 0x2019) {
    msg[22] = '1';
    outputnl(msg);
    printf("rmodseg = %04X ; *rmodsig = %04X\r\n", rmodseg, *rmodsig);
    return(1);
  }
  /* check last BUFFER byte (could be overwritten by cmdline) */
  if (BUFFER[sizeof(BUFFER) - 1] != 0xC7) {
    msg[22] = '2';
    outputnl(msg);
    return(2);
  }
  /* check that cmdline BUFFER's end hasn't been touched by something else */
  if (BUFFER[sizeof(BUFFER) - (CMDLINE_MAXLEN + 3)] != 0xC7) {
    msg[22] = '3';
    outputnl(msg);
    return(3);
  }
  /* all good */
  return(0);
}
 
 
/* parses command line the hard way (directly from PSP) */
static void parse_argv(struct config *cfg) {
 
  const unsigned char *cmdlinelen = (void *)0x80;
  char *cmdline = (void *)0x81;
 
  memset(cfg, 0, sizeof(*cfg));
 
  /* set a NULL terminator on cmdline */
  cmdline[*cmdlinelen] = 0;
 
  while (*cmdline != 0) {
 
    /* skip over any leading spaces */
    if (*cmdline == ' ') {
      cmdline++;
      continue;
    }
 
    if (*cmdline != '/') {
      output("Invalid parameter: ");
      outputnl(cmdline);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
      goto SKIP_TO_NEXT_ARG;
 
 
 
    }
 
    /* got a slash */
    cmdline++;  /* skip the slash */
    switch (*cmdline) {
      case 'c': /* /C = execute command and quit */
      case 'C':
        cfg->flags |= FLAG_EXEC_AND_QUIT;
        /* FALLTHRU */
      case 'k': /* /K = execute command and keep running */
      case 'K':
        cfg->execcmd = cmdline + 1;
        return;
 
      case 'e': /* preset the initial size of the environment block */
      case 'E':
        cmdline++;
        if (*cmdline == ':') cmdline++; /* could be /E:size */
        atous(&(cfg->envsiz), cmdline);
        if (cfg->envsiz < 64) cfg->envsiz = 0;
        break;
 
      case 'p': /* permanent shell (can't exit + run autoexec.bat) */
      case 'P':
        cfg->flags |= FLAG_PERMANENT;
        break;
 
      case '?':
        outputnl("Starts the SvarCOM command interpreter");
        outputnl("");
        outputnl("COMMAND /E:nnn [/[C|K] command]");
        outputnl("");
        outputnl("/E:nnn     Sets the environment size to nnn bytes");
        outputnl("/P         Makes the new command interpreter permanent (can't exit)");
        outputnl("/C         Executes the specified command and returns");
        outputnl("/K         Executes the specified command and continues running");
        exit(1);
        break;
 
      default:
        output("Invalid switch:");
        output(" ");
        outputnl(cmdline);
        break;
    }
 
    /* move to next argument or quit processing if end of cmdline */
    SKIP_TO_NEXT_ARG:
    while ((*cmdline != 0) && (*cmdline != ' ') && (*cmdline != '/')) cmdline++;
  }
}
 
 
/* builds the prompt string and displays it. buff is filled with a zero-terminated copy of the prompt. */
static void build_and_display_prompt(char *buff, unsigned short envseg) {
  char *s = buff;
  /* locate the prompt variable or use the default pattern */
  const char far *fmt = env_lookup_val(envseg, "PROMPT");
  if ((fmt == NULL) || (*fmt == 0)) fmt = "$p$g"; /* fallback to default if empty */
  /* build the prompt string based on pattern */
  for (; *fmt != 0; fmt++) {
    if (*fmt != '$') {
      *s = *fmt;
      s++;
      continue;
    }
    /* escape code ($P, etc) */
    fmt++;
    switch (*fmt) {
      case 'Q':  /* $Q = = (equal sign) */
      case 'q':
        *s = '=';
        s++;
        break;
      case '$':  /* $$ = $ (dollar sign) */
        *s = '$';
        s++;
        break;
      case 'T':  /* $t = current time */
      case 't':
        s += sprintf(s, "00:00"); /* TODO */
        break;
      case 'D':  /* $D = current date */
      case 'd':
        s += sprintf(s, "1985-07-29"); /* TODO */
        break;
      case 'P':  /* $P = current drive and path */
      case 'p':
        _asm {
          mov ah, 0x19    /* DOS 1+ - GET CURRENT DRIVE */
          int 0x21
          mov bx, s
          mov [bx], al  /* AL = drive (00 = A:, 01 = B:, etc */
        }
        *s += 'A';
        s++;
        *s = ':';
        s++;
        *s = '\\';
        s++;
        _asm {
          mov ah, 0x47    /* DOS 2+ - CWD - GET CURRENT DIRECTORY */
          xor dl,dl       /* DL = drive number (00h = default, 01h = A:, etc) */
          mov si, s       /* DS:SI -> 64-byte buffer for ASCIZ pathname */
          int 0x21
        }
        while (*s != 0) s++; /* move ptr forward to end of pathname */
        break;
      case 'V':  /* $V = DOS version number */
      case 'v':
        s += sprintf(s, "VER"); /* TODO */
        break;
      case 'N':  /* $N = current drive */
      case 'n':
        _asm {
          mov ah, 0x19    /* DOS 1+ - GET CURRENT DRIVE */
          int 0x21
          mov bx, s
          mov [bx], al  /* AL = drive (00 = A:, 01 = B:, etc */
        }
        *s += 'A';
        s++;
        break;
      case 'G':  /* $G = > (greater-than sign) */
      case 'g':
        *s = '>';
        s++;
        break;
      case 'L':  /* $L = < (less-than sign) */
      case 'l':
        *s = '<';
        s++;
        break;
      case 'B':  /* $B = | (pipe) */
      case 'b':
        *s = '|';
        s++;
        break;
      case 'H':  /* $H = backspace (erases previous character) */
      case 'h':
        *s = '\b';
        s++;
        break;
      case 'E':  /* $E = Escape code (ASCII 27) */
      case 'e':
        *s = 27;
        s++;
        break;
      case '_':  /* $_ = CR+LF */
        *s = '\r';
        s++;
        *s = '\n';
        s++;
        break;
    }
  }
  *s = 0;
  output(buff);
}
 
 
/* tries locating executable fname in path and fille res with result. returns 0 on success,
 * -1 on failed match and -2 on failed match + "don't even try with other paths"
 * format is filled the offset where extension starts in fname (-1 if not found) */
int lookup_cmd(char *res, const char *fname, const char *path, const char **extptr) {
  unsigned short lastbslash = 0xffff;
  unsigned short i, len;
  unsigned char explicitpath = 0;
 
  /* does the original fname had an explicit path prefix or explicit ext? */
  *extptr = NULL;
  for (i = 0; fname[i] != 0; i++) {
    switch (fname[i]) {
      case ':':
      case '\\':
        explicitpath = 1;
        *extptr = NULL; /* extension is the last dot AFTER all path delimiters */
        break;
      case '.':
        *extptr = fname + i + 1;
        break;
    }
  }
 
  /* normalize filename */
  if (file_truename(fname, res) != 0) return(-2);
 
  /* printf("truename: %s\r\n", res); */
 
  /* figure out where the command starts and if it has an explicit extension */
  for (len = 0; res[len] != 0; len++) {
    switch (res[len]) {
      case '?':   /* abort on any wildcard character */
      case '*':
        return(-2);
      case '\\':
        lastbslash = len;
        break;
    }
  }
 
  /* printf("lastbslash=%u\r\n", lastbslash); */
 
  /* if no path prefix in fname (':' or backslash), then assemble path+filename */
  if (!explicitpath) {
    if (path != NULL) {
      i = strlen(path);
    } else {
      i = 0;
    }
    if ((i != 0) && (path[i - 1] != '\\')) i++; /* add a byte for inserting a bkslash after path */
    memmove(res + i, res + lastbslash + 1, len - lastbslash);
    if (i != 0) {
      memmove(res, path, i);
      res[i - 1] = '\\';
    }
  }
 
  /* if no extension was initially provided, try matching COM, EXE, BAT */
  if (*extptr == NULL) {
    const char *ext[] = {".COM", ".EXE", ".BAT", NULL};
    len = strlen(res);
    for (i = 0; ext[i] != NULL; i++) {
      strcpy(res + len, ext[i]);
      /* printf("? '%s'\r\n", res); */
      *extptr = ext[i] + 1;
      if (file_getattr(res) >= 0) return(0);
    }
  } else { /* try finding it as-is */
    /* printf("? '%s'\r\n", res); */
    if (file_getattr(res) >= 0) return(0);
  }
 
  /* not found */
  if (explicitpath) return(-2); /* don't bother trying other paths, the caller had its own path preset anyway */
  return(-1);
}
 
 
static void run_as_external(char *buff, const char *cmdline, unsigned short envseg, struct rmod_props far *rmod) {
  char *cmdfile = buff + 512;
  const char far *pathptr;
  int lookup;
  unsigned short i;
  const char *ext;
  char *cmd = buff + 256;
  const char *cmdtail;
  char far *rmod_execprog = MK_FP(rmod->rmodseg, RMOD_OFFSET_EXECPROG);
  char far *rmod_cmdtail = MK_FP(rmod->rmodseg, 0x81);
  _Packed struct {
    unsigned short envseg;
    unsigned long cmdtail;
    unsigned long fcb1;
    unsigned long fcb2;
  } far *ExecParam = MK_FP(rmod->rmodseg, RMOD_OFFSET_EXECPARAM);
 
  /* find cmd and cmdtail */
  i = 0;
  cmdtail = cmdline;
  while (*cmdtail == ' ') cmdtail++; /* skip any leading spaces */
  while ((*cmdtail != ' ') && (*cmdtail != '/') && (*cmdtail != '+') && (*cmdtail != 0)) {
    cmd[i++] = *cmdtail;
    cmdtail++;
  }
  cmd[i] = 0;
 
  /* is this a command in curdir? */
  lookup = lookup_cmd(cmdfile, cmd, NULL, &ext);
  if (lookup == 0) {
    /* printf("FOUND LOCAL EXEC FILE: '%s'\r\n", cmdfile); */
    goto RUNCMDFILE;
  } else if (lookup == -2) {
    /* puts("NOT FOUND"); */
    return;
  }
 
  /* try matching something in PATH */
  pathptr = env_lookup_val(envseg, "PATH");
  if (pathptr == NULL) return;
 
  /* try each path in %PATH% */
  for (;;) {
    for (i = 0;; i++) {
      buff[i] = *pathptr;
      if ((buff[i] == 0) || (buff[i] == ';')) break;
      pathptr++;
    }
    buff[i] = 0;
    lookup = lookup_cmd(cmdfile, cmd, buff, &ext);
    if (lookup == 0) break;
    if (lookup == -2) return;
    if (*pathptr == ';') {
      pathptr++;
    } else {
      return;
    }
  }
 
  RUNCMDFILE:
 
  /* special handling of batch files */
  if ((ext != NULL) && (imatch(ext, "bat"))) {
    /* copy truename of the bat file to rmod buff */
    for (i = 0; cmdfile[i] != 0; i++) rmod->batfile[i] = cmdfile[i];
    rmod->batfile[i] = 0;
    /* copy args of the bat file to rmod buff */
    for (i = 0; cmdtail[i] != 0; i++) rmod->batargs[i] = cmdtail[i];
    /* reset the 'next line to execute' counter */
    rmod->batnextline = 0;
    /* remember the echo flag (in case bat file disables echo) */
    rmod->flags &= ~FLAG_ECHO_BEFORE_BAT;
    if (rmod->flags & FLAG_ECHOFLAG) rmod->flags |= FLAG_ECHO_BEFORE_BAT;
    return;
  }
 
  /* copy full filename to execute */
  for (i = 0; cmdfile[i] != 0; i++) rmod_execprog[i] = cmdfile[i];
  rmod_execprog[i] = 0;
 
  /* copy cmdtail to rmod's PSP and compute its len */
  for (i = 0; cmdtail[i] != 0; i++) rmod_cmdtail[i] = cmdtail[i];
  rmod_cmdtail[i] = '\r';
  rmod_cmdtail[-1] = i;
 
  /* set up rmod to execute the command */
 
  ExecParam->envseg = envseg;
  ExecParam->cmdtail = (unsigned long)MK_FP(rmod->rmodseg, 0x80); /* farptr, must be in PSP format (lenbyte args \r) */
  ExecParam->fcb1 = 0; /* TODO farptr */
  ExecParam->fcb2 = 0; /* TODO farptr */
  exit(0); /* let rmod do the job now */
}
 
 
static void set_comspec_to_self(unsigned short envseg) {
  unsigned short *psp_envseg = (void *)(0x2c); /* pointer to my env segment field in the PSP */
  char far *myenv = MK_FP(*psp_envseg, 0);
  unsigned short varcount;
  char buff[256] = "COMSPEC=";
  char *buffptr = buff + 8;
  /* who am i? look into my own environment, at the end of it should be my EXEPATH string */
  while (*myenv != 0) {
    /* consume a NULL-terminated string */
    while (*myenv != 0) myenv++;
    /* move to next string */
    myenv++;
  }
  /* get next word, if 1 then EXEPATH follows */
  myenv++;
  varcount = *myenv;
  myenv++;
  varcount |= (*myenv << 8);
  myenv++;
  if (varcount != 1) return; /* NO EXEPATH FOUND */
  while (*myenv != 0) {
    *buffptr = *myenv;
    buffptr++;
    myenv++;
  }
  *buffptr = 0;
  /* printf("EXEPATH: '%s'\r\n", buff); */
  env_setvar(envseg, buff);
}
 
 
/* wait for user input */
static void cmdline_getinput(unsigned short inpseg, unsigned short inpoff) {
  _asm {
    push ax
    push bx
    push cx
    push dx
    push ds
 
    /* is DOSKEY support present? (INT 2Fh, AX=4800h, returns non-zero in AL if present) */
    mov ax, 0x4800
    int 0x2f
    mov bl, al /* save doskey status in BL */
 
    /* set up buffered input to inpseg:inpoff */
    mov ax, inpseg
    push ax
    pop ds
    mov dx, inpoff
 
    /* execute either DOS input or DOSKEY */
    test bl, bl /* zf set if no DOSKEY present */
    jnz DOSKEY
 
    mov ah, 0x0a
    int 0x21
    jmp short DONE
 
    DOSKEY:
    mov ax, 0x4810
    int 0x2f
 
    DONE:
    /* terminate command with a CR/LF */
    mov ah, 0x02 /* display character in dl */
    mov dl, 0x0d
    int 0x21
    mov dl, 0x0a
    int 0x21
 
    pop ds
    pop dx
    pop cx
    pop bx
    pop ax
  }
}
 
 
/* fetches a line from batch file and write it to buff (NULL-terminated),
 * increments rmod counter and returns 0 on success. */
static int getbatcmd(char *buff, unsigned char buffmaxlen, struct rmod_props far *rmod) {
  unsigned short i;
  unsigned short batname_seg = FP_SEG(rmod->batfile);
  unsigned short batname_off = FP_OFF(rmod->batfile);
  unsigned short filepos_cx = rmod->batnextline >> 16;
  unsigned short filepos_dx = rmod->batnextline & 0xffff;
  unsigned char blen = 0;
 
  /* open file, jump to offset filpos, and read data into buff.
   * result in blen (unchanged if EOF or failure). */
  _asm {
    push ax
    push bx
    push cx
    push dx
 
    /* open file (read-only) */
    mov dx, batname_off
    mov ax, batname_seg
    push ds     /* save DS */
    mov ds, ax
    mov ax, 0x3d00
    int 0x21    /* handle in ax on success */
    pop ds      /* restore DS */
    jc DONE
    mov bx, ax  /* save handle to bx */
 
    /* jump to file offset CX:DX */
    mov ax, 0x4200
    mov cx, filepos_cx
    mov dx, filepos_dx
    int 0x21  /* CF clear on success, DX:AX set to cur pos */
    jc CLOSEANDQUIT
 
    /* read the line into buff */
    mov ah, 0x3f
    xor ch, ch
    mov cl, buffmaxlen
    mov dx, buff
    int 0x21 /* CF clear on success, AX=number of bytes read */
    jc CLOSEANDQUIT
    mov blen, al
 
    CLOSEANDQUIT:
    /* close file (handle in bx) */
    mov ah, 0x3e
    int 0x21
 
    DONE:
    pop dx
    pop cx
    pop bx
    pop ax
  }
 
  /* printf("blen=%u filepos_cx=%u filepos_dx=%u\r\n", blen, filepos_cx, filepos_dx); */
 
  /* on EOF - abort processing the bat file */
  if (blen == 0) goto OOPS;
 
  /* find nearest \n to inc batch offset and replace \r by NULL terminator
   * I support all CR/LF, CR- and LF-terminated batch files */
  for (i = 0; i < blen; i++) {
    if ((buff[i] == '\r') || (buff[i] == '\n')) {
      if ((buff[i] == '\r') && ((i+1) < blen) && (buff[i+1] == '\n')) rmod->batnextline += 1;
      break;
    }
  }
  buff[i] = 0;
  rmod->batnextline += i + 1;
 
  return(0);
 
  OOPS:
  rmod->batfile[0] = 0;
  rmod->batnextline = 0;
  return(-1);
}
 
 
int main(void) {
  static struct config cfg;
  static unsigned short far *rmod_envseg;
  static unsigned short far *lastexitcode;
  static struct rmod_props far *rmod;
  static char *cmdline;
 
  rmod = rmod_find(BUFFER_len);
  if (rmod == NULL) {
    /* look at command line parameters (in case env size if set there) */
    parse_argv(&cfg);
    rmod = rmod_install(cfg.envsiz, BUFFER, BUFFER_len);
    if (rmod == NULL) {
      outputnl("ERROR: rmod_install() failed");
      return(1);
    }
    /* copy flags to rmod's storage (and enable ECHO) */
    rmod->flags = cfg.flags | FLAG_ECHOFLAG;
    /* printf("rmod installed at %Fp\r\n", rmod); */
  } else {
    /* printf("rmod found at %Fp\r\n", rmod); */
    /* if I was spawned by rmod and FLAG_EXEC_AND_QUIT is set, then I should
     * die asap, because the command has been executed already, so I no longer
     * have a purpose in life */
    if (rmod->flags & FLAG_EXEC_AND_QUIT) sayonara(rmod);
  }
 
  /* install a few guardvals in memory to detect some cases of overflows */
  memguard_set();
 
  rmod_envseg = MK_FP(rmod->rmodseg, RMOD_OFFSET_ENVSEG);
  lastexitcode = MK_FP(rmod->rmodseg, RMOD_OFFSET_LEXITCODE);
 
  /* make COMPSEC point to myself */
  set_comspec_to_self(*rmod_envseg);
 
/*  {
    unsigned short envsiz;
    unsigned short far *sizptr = MK_FP(*rmod_envseg - 1, 3);
    envsiz = *sizptr;
    envsiz *= 16;
    printf("rmod_inpbuff at %04X:%04X, env_seg at %04X:0000 (env_size = %u bytes)\r\n", rmod->rmodseg, RMOD_OFFSET_INPBUFF, *rmod_envseg, envsiz);
  }*/
 
  /* on /P check for the presence of AUTOEXEC.BAT and execute it if found */
  if (cfg.flags & FLAG_PERMANENT) {
    if (file_getattr("AUTOEXEC.BAT") >= 0) cfg.execcmd = "AUTOEXEC.BAT";
  }
 
  do {
    /* terminate previous command with a CR/LF if ECHO ON (but not during BAT processing) */
    if ((rmod->flags & FLAG_ECHOFLAG) && (rmod->batfile[0] == 0)) outputnl("");
 
    SKIP_NEWLINE:
 
    /* cancel any redirections that may have been set up before */
    redir_revert();
 
    /* memory check */
    memguard_check(rmod->rmodseg);
 
    /* preset cmdline to point at the end of my general-purpose buffer (with
     * one extra byte for the NULL terminator and another for memguard val) */
    cmdline = BUFFER + sizeof(BUFFER) - (CMDLINE_MAXLEN + 2);
 
    /* (re)load translation strings if needed */
    nls_langreload(BUFFER, *rmod_envseg);
 
    /* skip user input if I have a command to exec (/C or /K) */
    if (cfg.execcmd != NULL) {
      cmdline = cfg.execcmd;
      cfg.execcmd = NULL;
      goto EXEC_CMDLINE;
    }
 
    /* if batch file is being executed -> fetch next line */
    if (rmod->batfile[0] != 0) {
      if (getbatcmd(cmdline, CMDLINE_MAXLEN, rmod) != 0) { /* end of batch */
        /* restore echo flag as it was before running the bat file */
        rmod->flags &= ~FLAG_ECHOFLAG;
        if (rmod->flags & FLAG_ECHO_BEFORE_BAT) rmod->flags |= FLAG_ECHOFLAG;
        continue;
      }
      /* skip any leading spaces */
      while (*cmdline == ' ') cmdline++;
      /* output prompt and command on screen if echo on and command is not
       * inhibiting it with the @ prefix */
      if ((rmod->flags & FLAG_ECHOFLAG) && (cmdline[0] != '@')) {
        build_and_display_prompt(BUFFER, *rmod_envseg);
        outputnl(cmdline);
      }
      /* skip the @ prefix if present, it is no longer useful */
      if (cmdline[0] == '@') cmdline++;
    } else {
      /* interactive mode: display prompt (if echo enabled) and wait for user
       * command line */
      if (rmod->flags & FLAG_ECHOFLAG) build_and_display_prompt(BUFFER, *rmod_envseg);
      /* collect user input */
      cmdline_getinput(FP_SEG(rmod->inputbuf), FP_OFF(rmod->inputbuf));
      /* copy it to local cmdline */
      if (rmod->inputbuf[1] != 0) _fmemcpy(cmdline, rmod->inputbuf + 2, rmod->inputbuf[1]);
      cmdline[(unsigned)(rmod->inputbuf[1])] = 0; /* zero-terminate local buff (oriignal is '\r'-terminated) */
    }
 
    /* if nothing entered, loop again (but without appending an extra CR/LF) */
    if (cmdline[0] == 0) goto SKIP_NEWLINE;
 
    /* I jump here when I need to exec an initial command (/C or /K) */
    EXEC_CMDLINE:
 
    /* move pointer forward to skip over any leading spaces */
    while (*cmdline == ' ') cmdline++;
 
    /* update rmod's ptr to COMPSPEC so it is always up to date */
    rmod_updatecomspecptr(rmod->rmodseg, *rmod_envseg);
 
    /* handle redirections (if any) */
    if (redir_parsecmd(cmdline, BUFFER) != 0) {
      outputnl("");
      continue;
    }
 
    /* try matching (and executing) an internal command */
    if (cmd_process(rmod, *rmod_envseg, cmdline, BUFFER) >= -1) {
      /* internal command executed */
      redir_revert(); /* revert stdout (in case it was redirected) */
      continue;
    }
 
    /* if here, then this was not an internal command */
    run_as_external(BUFFER, cmdline, *rmod_envseg, rmod);
    /* perhaps this is a newly launched BAT file */
    if ((rmod->batfile[0] != 0) && (rmod->batnextline == 0)) goto SKIP_NEWLINE;
 
    /* revert stdout (so the err msg is not redirected) */
    redir_revert();
 
    /* run_as_external() does not return on success, if I am still alive then
     * external command failed to execute */
    outputnl("Bad command or file name");
 
  } while ((rmod->flags & FLAG_EXEC_AND_QUIT) == 0);
 
  sayonara(rmod);
  return(0);
}
 

Rev 490	Rev 491
1	`/* This file is part of the SvarCOM project and is published under the terms`	1	`/* This file is part of the SvarCOM project and is published under the terms`
2	`* of the MIT license.`	2	`* of the MIT license.`
3	`*`	3	`*`
4	`* Copyright (C) 2021 Mateusz Viste`	4	`* Copyright (C) 2021 Mateusz Viste`
5	`*`	5	`*`
6	`* Permission is hereby granted, free of charge, to any person obtaining a`	6	`* Permission is hereby granted, free of charge, to any person obtaining a`
7	`* copy of this software and associated documentation files (the "Software"),`	7	`* copy of this software and associated documentation files (the "Software"),`
8	`* to deal in the Software without restriction, including without limitation`	8	`* to deal in the Software without restriction, including without limitation`
9	`* the rights to use, copy, modify, merge, publish, distribute, sublicense,`	9	`* the rights to use, copy, modify, merge, publish, distribute, sublicense,`
10	`* and/or sell copies of the Software, and to permit persons to whom the`	10	`* and/or sell copies of the Software, and to permit persons to whom the`
11	`* Software is furnished to do so, subject to the following conditions:`	11	`* Software is furnished to do so, subject to the following conditions:`
12	`*`	12	`*`
13	`* The above copyright notice and this permission notice shall be included in`	13	`* The above copyright notice and this permission notice shall be included in`
14	`* all copies or substantial portions of the Software.`	14	`* all copies or substantial portions of the Software.`
15	`*`	15	`*`
16	`* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR`	16	`* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR`
17	`* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,`	17	`* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,`
18	`* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE`	18	`* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE`
19	`* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER`	19	`* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER`
20	`* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING`	20	`* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING`
21	`* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER`	21	`* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER`
22	`* DEALINGS IN THE SOFTWARE.`	22	`* DEALINGS IN THE SOFTWARE.`
23	`*/`	23	`*/`
24		24
25	`/*`	25	`/*`
26	`* SvarCOM is a command-line interpreter.`	26	`* SvarCOM is a command-line interpreter.`
27	`*`	27	`*`
28	`* a little memory area is allocated as high as possible. it contains:`	28	`* a little memory area is allocated as high as possible. it contains:`
29	`* - a signature (like XMS drivers do)`	29	`* - a signature (like XMS drivers do)`
30	`* - a routine for exec'ing programs`	30	`* - a routine for exec'ing programs`
31	`* - a "last command" buffer for input history`	31	`* - a "last command" buffer for input history`
32	`*`	32	`*`
33	`* when svarcom starts, it tries locating the routine in memory.`	33	`* when svarcom starts, it tries locating the routine in memory.`
34	`*`	34	`*`
35	`* if found:`	35	`* if found:`
36	`* waits for user input and processes it. if execing something is required, set the "next exec" field in routine's memory and quit.`	36	`* waits for user input and processes it. if execing something is required, set the "next exec" field in routine's memory and quit.`
37	`*`	37	`*`
38	`* if not found:`	38	`* if not found:`
39	`* installs it by creating a new PSP, set int 22 vector to the routine, set my "parent PSP" to the routine`	39	`* installs it by creating a new PSP, set int 22 vector to the routine, set my "parent PSP" to the routine`
40	`* and quit.`	40	`* and quit.`
41	`*`	41	`*`
42	`* PSP structure`	42	`* PSP structure`
43	`* http://www.piclist.com/techref/dos/psps.htm`	43	`* http://www.piclist.com/techref/dos/psps.htm`
44	`*`	44	`*`
45	`*`	45	`*`
46	`*`	46	`*`
47	`* === MCB ===`	47	`* === MCB ===`
48	`*`	48	`*`
49	`* each time that DOS allocates memory, it prefixes the allocated memory with`	49	`* each time that DOS allocates memory, it prefixes the allocated memory with`
50	`* a 16-bytes structure called a "Memory Control Block" (MCB). This control`	50	`* a 16-bytes structure called a "Memory Control Block" (MCB). This control`
51	`* block has the following structure:`	51	`* block has the following structure:`
52	`*`	52	`*`
53	`* Offset Size Description`	53	`* Offset Size Description`
54	`* 00h byte 'M' = non-last member of the MCB chain`	54	`* 00h byte 'M' = non-last member of the MCB chain`
55	`* 'Z' = indicates last entry in MCB chain`	55	`* 'Z' = indicates last entry in MCB chain`
56	`* other values cause "Memory Allocation Failure" on exit`	56	`* other values cause "Memory Allocation Failure" on exit`
57	`* 01h word PSP segment address of the owner (Process Id)`	57	`* 01h word PSP segment address of the owner (Process Id)`
58	`* possible values:`	58	`* possible values:`
59	`* 0 = free`	59	`* 0 = free`
60	`* 8 = Allocated by DOS before first user pgm loaded`	60	`* 8 = Allocated by DOS before first user pgm loaded`
61	`* other = Process Id/PSP segment address of owner`	61	`* other = Process Id/PSP segment address of owner`
62	`* 03h word number of paragraphs related to this MCB (excluding MCB)`	62	`* 03h word number of paragraphs related to this MCB (excluding MCB)`
63	`* 05h 11 bytes reserved`	63	`* 05h 11 bytes reserved`
64	`* 10h ... start of actual allocated memory block`	64	`* 10h ... start of actual allocated memory block`
65	`*/`	65	`*/`
66		66
67	`#include <i86.h>`	67	`#include <i86.h>`
68	`#include <dos.h>`	68	`#include <dos.h>`
69	`#include <stdio.h>`	69	`#include <stdio.h>`
70	`#include <stdlib.h>`	70	`#include <stdlib.h>`
71	`#include <string.h>`	71	`#include <string.h>`
72		72
73	`#include <process.h>`	73	`#include <process.h>`
74		74
75	`#include "cmd.h"`	75	`#include "cmd.h"`
76	`#include "env.h"`	76	`#include "env.h"`
77	`#include "helpers.h"`	77	`#include "helpers.h"`
78	`#include "redir.h"`	78	`#include "redir.h"`
79	`#include "rmodinit.h"`	79	`#include "rmodinit.h"`
80	`#include "sayonara.h"`	80	`#include "sayonara.h"`
81		81
82	`#include "rmodcore.h" /* rmod binary inside a BUFFER array */`	82	`#include "rmodcore.h" /* rmod binary inside a BUFFER array */`
83		83
84	`struct config {`	84	`struct config {`
85	`unsigned char flags; /* command.com flags, as defined in rmodinit.h */`	85	`unsigned char flags; /* command.com flags, as defined in rmodinit.h */`
86	`char *execcmd;`	86	`char *execcmd;`
87	`unsigned short envsiz;`	87	`unsigned short envsiz;`
88	`};`	88	`};`
89		89
90	`/* max length of the cmdline storage (bytes) - includes also max length of`	90	`/* max length of the cmdline storage (bytes) - includes also max length of`
91	`* line loaded from a BAT file (no more than 255 bytes!) */`	91	`* line loaded from a BAT file (no more than 255 bytes!) */`
92	`#define CMDLINE_MAXLEN 255`	92	`#define CMDLINE_MAXLEN 255`
93		93
94		94
95	`/* sets guard values at a few places in memory for later detection of`	95	`/* sets guard values at a few places in memory for later detection of`
96	`* overflows via memguard_check() */`	96	`* overflows via memguard_check() */`
97	`static void memguard_set(void) {`	97	`static void memguard_set(void) {`
98	`BUFFER[sizeof(BUFFER) - 1] = 0xC7;`	98	`BUFFER[sizeof(BUFFER) - 1] = 0xC7;`
99	`BUFFER[sizeof(BUFFER) - (CMDLINE_MAXLEN + 3)] = 0xC7;`	99	`BUFFER[sizeof(BUFFER) - (CMDLINE_MAXLEN + 3)] = 0xC7;`
100	`}`	100	`}`
101		101
102		102
103	`/* checks for valguards at specific memory locations, returns 0 on success */`	103	`/* checks for valguards at specific memory locations, returns 0 on success */`
104	`static int memguard_check(unsigned short rmodseg) {`	104	`static int memguard_check(unsigned short rmodseg) {`
105	`/* check RMOD signature (would be overwritten in case of stack overflow */`	105	`/* check RMOD signature (would be overwritten in case of stack overflow */`
106	`static char msg[] = "!! MEMORY CORRUPTION ## DETECTED !!";`	106	`static char msg[] = "!! MEMORY CORRUPTION ## DETECTED !!";`
107	`unsigned short far *rmodsig = MK_FP(rmodseg, 0x100 + 6);`	107	`unsigned short far *rmodsig = MK_FP(rmodseg, 0x100 + 6);`
108	`if (*rmodsig != 0x2019) {`	108	`if (*rmodsig != 0x2019) {`
109	`msg[22] = '1';`	109	`msg[22] = '1';`
110	`outputnl(msg);`	110	`outputnl(msg);`
111	`printf("rmodseg = %04X ; rmodsig = %04X\r\n", rmodseg, rmodsig);`	111	`printf("rmodseg = %04X ; rmodsig = %04X\r\n", rmodseg, rmodsig);`
112	`return(1);`	112	`return(1);`
113	`}`	113	`}`
114	`/* check last BUFFER byte (could be overwritten by cmdline) */`	114	`/* check last BUFFER byte (could be overwritten by cmdline) */`
115	`if (BUFFER[sizeof(BUFFER) - 1] != 0xC7) {`	115	`if (BUFFER[sizeof(BUFFER) - 1] != 0xC7) {`
116	`msg[22] = '2';`	116	`msg[22] = '2';`
117	`outputnl(msg);`	117	`outputnl(msg);`
118	`return(2);`	118	`return(2);`
119	`}`	119	`}`
120	`/* check that cmdline BUFFER's end hasn't been touched by something else */`	120	`/* check that cmdline BUFFER's end hasn't been touched by something else */`
121	`if (BUFFER[sizeof(BUFFER) - (CMDLINE_MAXLEN + 3)] != 0xC7) {`	121	`if (BUFFER[sizeof(BUFFER) - (CMDLINE_MAXLEN + 3)] != 0xC7) {`
122	`msg[22] = '3';`	122	`msg[22] = '3';`
123	`outputnl(msg);`	123	`outputnl(msg);`
124	`return(3);`	124	`return(3);`
125	`}`	125	`}`
126	`/* all good */`	126	`/* all good */`
127	`return(0);`	127	`return(0);`
128	`}`	128	`}`
129		129
130		130
131	`/* parses command line the hard way (directly from PSP) */`	131	`/* parses command line the hard way (directly from PSP) */`
132	`static void parse_argv(struct config *cfg) {`	132	`static void parse_argv(struct config *cfg) {`
133	`unsigned short i;`	-
134	`const unsigned char cmdlinelen = (unsigned char )0x80;`	133	`const unsigned char cmdlinelen = (void )0x80;`
135	`char cmdline = (char )0x81;`	134	`char cmdline = (void )0x81;`
136		135
137	`memset(cfg, 0, sizeof(*cfg));`	136	`memset(cfg, 0, sizeof(*cfg));`
138		137
139	`/* set a NULL terminator on cmdline */`	138	`/* set a NULL terminator on cmdline */`
140	`cmdline[*cmdlinelen] = 0;`	139	`cmdline[*cmdlinelen] = 0;`
141		140
142	`for (i = 0;;) {`	141	`while (*cmdline != 0) {`
143		142
144	`/* skip over any leading spaces */`	143	`/* skip over any leading spaces */`
145	`for (;; i++) {`	144	`if (*cmdline == ' ') {`
146	`if (cmdline[i] == 0) return;`	145	`cmdline++;`
147	`if (cmdline[i] != ' ') break;`	146	`continue;`
148	`}`	147	`}`
149		148
150	`if (cmdline[i] != '/') {`	149	`if (*cmdline != '/') {`
151	`output("Invalid parameter: ");`	150	`output("Invalid parameter: ");`
152	`outputnl(cmdline + i);`	151	`outputnl(cmdline);`
153	`/* exit(1); */`	-
154	`} else {`	-
155	`i++; /* skip the slash */`	-
156	`switch (cmdline[i]) {`	-
157	`case 'c': /* /C = execute command and quit */`	-
158	`case 'C':`	-
159	`cfg->flags \|= FLAG_EXEC_AND_QUIT;`	-
160	`/* FALLTHRU */`	-
161	`case 'k': /* /K = execute command and keep running */`	-
162	`case 'K':`	-
163	`cfg->execcmd = cmdline + i + 1;`	-
164	`return;`	-
165		-
166	`case 'e': /* preset the initial size of the environment block */`	-
167	`case 'E':`	-
168	`i++;`	-
169	`if (cmdline[i] == ':') i++; /* could be /E:size */`	-
170	`atous(&(cfg->envsiz), cmdline + i);`	-
171	`if (cfg->envsiz < 64) cfg->envsiz = 0;`	-
172	`break;`	-
173		-
174	`case 'p': /* permanent shell (can't exit + run autoexec.bat) */`	-
175	`case 'P':`	-
176	`cfg->flags \|= FLAG_PERMANENT;`	-
177	`break;`	-
178		-
179	`case '?':`	-
180	`outputnl("Starts the SvarCOM command interpreter");`	-
181	`outputnl("");`	-
182	`outputnl("COMMAND /E:nnn [/[C\|K] command]");`	-
183	`outputnl("");`	-
184	`outputnl("/E:nnn Sets the environment size to nnn bytes");`	-
185	`outputnl("/P Makes the new command interpreter permanent (can't exit)");`	-
186	`outputnl("/C Executes the specified command and returns");`	-
187	`outputnl("/K Executes the specified command and continues running");`	-
188	`exit(1);`	-
189	`break;`	-
190		-
191	`default:`	-
192	`output("Invalid switch:");`	-
193	`output(" ");`	-
194	`outputnl(cmdline + i);`	152	`goto SKIP_TO_NEXT_ARG;`
195	`exit(1);`	-
196	`break;`	-
197	`}`	-
198	`}`	153	`}`
199		154
-		155	`/* got a slash */`
-		156	`cmdline++; /* skip the slash */`
-		157	`switch (*cmdline) {`
-		158	`case 'c': /* /C = execute command and quit */`
-		159	`case 'C':`
-		160	`cfg->flags \|= FLAG_EXEC_AND_QUIT;`
-		161	`/* FALLTHRU */`
-		162	`case 'k': /* /K = execute command and keep running */`
-		163	`case 'K':`
-		164	`cfg->execcmd = cmdline + 1;`
-		165	`return;`
-		166
200	`/* move to next argument or quit processing if end of cmdline */`	167	`case 'e': /* preset the initial size of the environment block */`
-		168	`case 'E':`
-		169	`cmdline++;`
201	`for (i++; (cmdline[i] != 0) && (cmdline[i] != ' ') && (cmdline[i] != '/'); i++);`	170	`if (cmdline == ':') cmdline++; / could be /E:size */`
-		171	`atous(&(cfg->envsiz), cmdline);`
-		172	`if (cfg->envsiz < 64) cfg->envsiz = 0;`
-		173	`break;`
-		174
-		175	`case 'p': /* permanent shell (can't exit + run autoexec.bat) */`
-		176	`case 'P':`
-		177	`cfg->flags \|= FLAG_PERMANENT;`
-		178	`break;`
-		179
-		180	`case '?':`
-		181	`outputnl("Starts the SvarCOM command interpreter");`
-		182	`outputnl("");`
-		183	`outputnl("COMMAND /E:nnn [/[C\|K] command]");`
-		184	`outputnl("");`
-		185	`outputnl("/E:nnn Sets the environment size to nnn bytes");`
-		186	`outputnl("/P Makes the new command interpreter permanent (can't exit)");`
-		187	`outputnl("/C Executes the specified command and returns");`
-		188	`outputnl("/K Executes the specified command and continues running");`
-		189	`exit(1);`
-		190	`break;`
-		191
-		192	`default:`
-		193	`output("Invalid switch:");`
-		194	`output(" ");`
-		195	`outputnl(cmdline);`
-		196	`break;`
-		197	`}`
202		198
-		199	`/* move to next argument or quit processing if end of cmdline */`
-		200	`SKIP_TO_NEXT_ARG:`
-		201	`while ((cmdline != 0) && (cmdline != ' ') && (*cmdline != '/')) cmdline++;`
203	`}`	202	`}`
204	`}`	203	`}`
205		204
206		205
207	`/* builds the prompt string and displays it. buff is filled with a zero-terminated copy of the prompt. */`	206	`/* builds the prompt string and displays it. buff is filled with a zero-terminated copy of the prompt. */`
208	`static void build_and_display_prompt(char *buff, unsigned short envseg) {`	207	`static void build_and_display_prompt(char *buff, unsigned short envseg) {`
209	`char *s = buff;`	208	`char *s = buff;`
210	`/* locate the prompt variable or use the default pattern */`	209	`/* locate the prompt variable or use the default pattern */`
211	`const char far *fmt = env_lookup_val(envseg, "PROMPT");`	210	`const char far *fmt = env_lookup_val(envseg, "PROMPT");`
212	`if ((fmt == NULL) \|\| (fmt == 0)) fmt = "$p$g"; / fallback to default if empty */`	211	`if ((fmt == NULL) \|\| (fmt == 0)) fmt = "$p$g"; / fallback to default if empty */`
213	`/* build the prompt string based on pattern */`	212	`/* build the prompt string based on pattern */`
214	`for (; *fmt != 0; fmt++) {`	213	`for (; *fmt != 0; fmt++) {`
215	`if (*fmt != '$') {`	214	`if (*fmt != '$') {`
216	`s = fmt;`	215	`s = fmt;`
217	`s++;`	216	`s++;`
218	`continue;`	217	`continue;`
219	`}`	218	`}`
220	`/* escape code ($P, etc) */`	219	`/* escape code ($P, etc) */`
221	`fmt++;`	220	`fmt++;`
222	`switch (*fmt) {`	221	`switch (*fmt) {`
223	`case 'Q': /* $Q = = (equal sign) */`	222	`case 'Q': /* $Q = = (equal sign) */`
224	`case 'q':`	223	`case 'q':`
225	`*s = '=';`	224	`*s = '=';`
226	`s++;`	225	`s++;`
227	`break;`	226	`break;`
228	`case '$': /* $$ = $ (dollar sign) */`	227	`case '$': /* $$ = $ (dollar sign) */`
229	`*s = '$';`	228	`*s = '$';`
230	`s++;`	229	`s++;`
231	`break;`	230	`break;`
232	`case 'T': /* $t = current time */`	231	`case 'T': /* $t = current time */`
233	`case 't':`	232	`case 't':`
234	`s += sprintf(s, "00:00"); /* TODO */`	233	`s += sprintf(s, "00:00"); /* TODO */`
235	`break;`	234	`break;`
236	`case 'D': /* $D = current date */`	235	`case 'D': /* $D = current date */`
237	`case 'd':`	236	`case 'd':`
238	`s += sprintf(s, "1985-07-29"); /* TODO */`	237	`s += sprintf(s, "1985-07-29"); /* TODO */`
239	`break;`	238	`break;`
240	`case 'P': /* $P = current drive and path */`	239	`case 'P': /* $P = current drive and path */`
241	`case 'p':`	240	`case 'p':`
242	`_asm {`	241	`_asm {`
243	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`	242	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`
244	`int 0x21`	243	`int 0x21`
245	`mov bx, s`	244	`mov bx, s`
246	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`	245	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`
247	`}`	246	`}`
248	`*s += 'A';`	247	`*s += 'A';`
249	`s++;`	248	`s++;`
250	`*s = ':';`	249	`*s = ':';`
251	`s++;`	250	`s++;`
252	`*s = '\\';`	251	`*s = '\\';`
253	`s++;`	252	`s++;`
254	`_asm {`	253	`_asm {`
255	`mov ah, 0x47 /* DOS 2+ - CWD - GET CURRENT DIRECTORY */`	254	`mov ah, 0x47 /* DOS 2+ - CWD - GET CURRENT DIRECTORY */`
256	`xor dl,dl /* DL = drive number (00h = default, 01h = A:, etc) */`	255	`xor dl,dl /* DL = drive number (00h = default, 01h = A:, etc) */`
257	`mov si, s /* DS:SI -> 64-byte buffer for ASCIZ pathname */`	256	`mov si, s /* DS:SI -> 64-byte buffer for ASCIZ pathname */`
258	`int 0x21`	257	`int 0x21`
259	`}`	258	`}`
260	`while (s != 0) s++; / move ptr forward to end of pathname */`	259	`while (s != 0) s++; / move ptr forward to end of pathname */`
261	`break;`	260	`break;`
262	`case 'V': /* $V = DOS version number */`	261	`case 'V': /* $V = DOS version number */`
263	`case 'v':`	262	`case 'v':`
264	`s += sprintf(s, "VER"); /* TODO */`	263	`s += sprintf(s, "VER"); /* TODO */`
265	`break;`	264	`break;`
266	`case 'N': /* $N = current drive */`	265	`case 'N': /* $N = current drive */`
267	`case 'n':`	266	`case 'n':`
268	`_asm {`	267	`_asm {`
269	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`	268	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`
270	`int 0x21`	269	`int 0x21`
271	`mov bx, s`	270	`mov bx, s`
272	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`	271	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`
273	`}`	272	`}`
274	`*s += 'A';`	273	`*s += 'A';`
275	`s++;`	274	`s++;`
276	`break;`	275	`break;`
277	`case 'G': /* $G = > (greater-than sign) */`	276	`case 'G': /* $G = > (greater-than sign) */`
278	`case 'g':`	277	`case 'g':`
279	`*s = '>';`	278	`*s = '>';`
280	`s++;`	279	`s++;`
281	`break;`	280	`break;`
282	`case 'L': /* $L = < (less-than sign) */`	281	`case 'L': /* $L = < (less-than sign) */`
283	`case 'l':`	282	`case 'l':`
284	`*s = '<';`	283	`*s = '<';`
285	`s++;`	284	`s++;`
286	`break;`	285	`break;`
287	`case 'B': /* $B = \| (pipe) */`	286	`case 'B': /* $B = \| (pipe) */`
288	`case 'b':`	287	`case 'b':`
289	`*s = '\|';`	288	`*s = '\|';`
290	`s++;`	289	`s++;`
291	`break;`	290	`break;`
292	`case 'H': /* $H = backspace (erases previous character) */`	291	`case 'H': /* $H = backspace (erases previous character) */`
293	`case 'h':`	292	`case 'h':`
294	`*s = '\b';`	293	`*s = '\b';`
295	`s++;`	294	`s++;`
296	`break;`	295	`break;`
297	`case 'E': /* $E = Escape code (ASCII 27) */`	296	`case 'E': /* $E = Escape code (ASCII 27) */`
298	`case 'e':`	297	`case 'e':`
299	`*s = 27;`	298	`*s = 27;`
300	`s++;`	299	`s++;`
301	`break;`	300	`break;`
302	`case '_': /* $_ = CR+LF */`	301	`case '_': /* $_ = CR+LF */`
303	`*s = '\r';`	302	`*s = '\r';`
304	`s++;`	303	`s++;`
305	`*s = '\n';`	304	`*s = '\n';`
306	`s++;`	305	`s++;`
307	`break;`	306	`break;`
308	`}`	307	`}`
309	`}`	308	`}`
310	`*s = 0;`	309	`*s = 0;`
311	`output(buff);`	310	`output(buff);`
312	`}`	311	`}`
313		312
314		313
315	`/* tries locating executable fname in path and fille res with result. returns 0 on success,`	314	`/* tries locating executable fname in path and fille res with result. returns 0 on success,`
316	`* -1 on failed match and -2 on failed match + "don't even try with other paths"`	315	`* -1 on failed match and -2 on failed match + "don't even try with other paths"`
317	`* format is filled the offset where extension starts in fname (-1 if not found) */`	316	`* format is filled the offset where extension starts in fname (-1 if not found) */`
318	`int lookup_cmd(char res, const char fname, const char path, const char *extptr) {`	317	`int lookup_cmd(char res, const char fname, const char path, const char *extptr) {`
319	`unsigned short lastbslash = 0xffff;`	318	`unsigned short lastbslash = 0xffff;`
320	`unsigned short i, len;`	319	`unsigned short i, len;`
321	`unsigned char explicitpath = 0;`	320	`unsigned char explicitpath = 0;`
322		321
323	`/* does the original fname had an explicit path prefix or explicit ext? */`	322	`/* does the original fname had an explicit path prefix or explicit ext? */`
324	`*extptr = NULL;`	323	`*extptr = NULL;`
325	`for (i = 0; fname[i] != 0; i++) {`	324	`for (i = 0; fname[i] != 0; i++) {`
326	`switch (fname[i]) {`	325	`switch (fname[i]) {`
327	`case ':':`	326	`case ':':`
328	`case '\\':`	327	`case '\\':`
329	`explicitpath = 1;`	328	`explicitpath = 1;`
330	`extptr = NULL; / extension is the last dot AFTER all path delimiters */`	329	`extptr = NULL; / extension is the last dot AFTER all path delimiters */`
331	`break;`	330	`break;`
332	`case '.':`	331	`case '.':`
333	`*extptr = fname + i + 1;`	332	`*extptr = fname + i + 1;`
334	`break;`	333	`break;`
335	`}`	334	`}`
336	`}`	335	`}`
337		336
338	`/* normalize filename */`	337	`/* normalize filename */`
339	`if (file_truename(fname, res) != 0) return(-2);`	338	`if (file_truename(fname, res) != 0) return(-2);`
340		339
341	`/* printf("truename: %s\r\n", res); */`	340	`/* printf("truename: %s\r\n", res); */`
342		341
343	`/* figure out where the command starts and if it has an explicit extension */`	342	`/* figure out where the command starts and if it has an explicit extension */`
344	`for (len = 0; res[len] != 0; len++) {`	343	`for (len = 0; res[len] != 0; len++) {`
345	`switch (res[len]) {`	344	`switch (res[len]) {`
346	`case '?': /* abort on any wildcard character */`	345	`case '?': /* abort on any wildcard character */`
347	`case '*':`	346	`case '*':`
348	`return(-2);`	347	`return(-2);`
349	`case '\\':`	348	`case '\\':`
350	`lastbslash = len;`	349	`lastbslash = len;`
351	`break;`	350	`break;`
352	`}`	351	`}`
353	`}`	352	`}`
354		353
355	`/* printf("lastbslash=%u\r\n", lastbslash); */`	354	`/* printf("lastbslash=%u\r\n", lastbslash); */`
356		355
357	`/* if no path prefix in fname (':' or backslash), then assemble path+filename */`	356	`/* if no path prefix in fname (':' or backslash), then assemble path+filename */`
358	`if (!explicitpath) {`	357	`if (!explicitpath) {`
359	`if (path != NULL) {`	358	`if (path != NULL) {`
360	`i = strlen(path);`	359	`i = strlen(path);`
361	`} else {`	360	`} else {`
362	`i = 0;`	361	`i = 0;`
363	`}`	362	`}`
364	`if ((i != 0) && (path[i - 1] != '\\')) i++; /* add a byte for inserting a bkslash after path */`	363	`if ((i != 0) && (path[i - 1] != '\\')) i++; /* add a byte for inserting a bkslash after path */`
365	`memmove(res + i, res + lastbslash + 1, len - lastbslash);`	364	`memmove(res + i, res + lastbslash + 1, len - lastbslash);`
366	`if (i != 0) {`	365	`if (i != 0) {`
367	`memmove(res, path, i);`	366	`memmove(res, path, i);`
368	`res[i - 1] = '\\';`	367	`res[i - 1] = '\\';`
369	`}`	368	`}`
370	`}`	369	`}`
371		370
372	`/* if no extension was initially provided, try matching COM, EXE, BAT */`	371	`/* if no extension was initially provided, try matching COM, EXE, BAT */`
373	`if (*extptr == NULL) {`	372	`if (*extptr == NULL) {`
374	`const char *ext[] = {".COM", ".EXE", ".BAT", NULL};`	373	`const char *ext[] = {".COM", ".EXE", ".BAT", NULL};`
375	`len = strlen(res);`	374	`len = strlen(res);`
376	`for (i = 0; ext[i] != NULL; i++) {`	375	`for (i = 0; ext[i] != NULL; i++) {`
377	`strcpy(res + len, ext[i]);`	376	`strcpy(res + len, ext[i]);`
378	`/* printf("? '%s'\r\n", res); */`	377	`/* printf("? '%s'\r\n", res); */`
379	`*extptr = ext[i] + 1;`	378	`*extptr = ext[i] + 1;`
380	`if (file_getattr(res) >= 0) return(0);`	379	`if (file_getattr(res) >= 0) return(0);`
381	`}`	380	`}`
382	`} else { /* try finding it as-is */`	381	`} else { /* try finding it as-is */`
383	`/* printf("? '%s'\r\n", res); */`	382	`/* printf("? '%s'\r\n", res); */`
384	`if (file_getattr(res) >= 0) return(0);`	383	`if (file_getattr(res) >= 0) return(0);`
385	`}`	384	`}`
386		385
387	`/* not found */`	386	`/* not found */`
388	`if (explicitpath) return(-2); /* don't bother trying other paths, the caller had its own path preset anyway */`	387	`if (explicitpath) return(-2); /* don't bother trying other paths, the caller had its own path preset anyway */`
389	`return(-1);`	388	`return(-1);`
390	`}`	389	`}`
391		390
392		391
393	`static void run_as_external(char buff, const char cmdline, unsigned short envseg, struct rmod_props far *rmod) {`	392	`static void run_as_external(char buff, const char cmdline, unsigned short envseg, struct rmod_props far *rmod) {`
394	`char *cmdfile = buff + 512;`	393	`char *cmdfile = buff + 512;`
395	`const char far *pathptr;`	394	`const char far *pathptr;`
396	`int lookup;`	395	`int lookup;`
397	`unsigned short i;`	396	`unsigned short i;`
398	`const char *ext;`	397	`const char *ext;`
399	`char *cmd = buff + 256;`	398	`char *cmd = buff + 256;`
400	`const char *cmdtail;`	399	`const char *cmdtail;`
401	`char far *rmod_execprog = MK_FP(rmod->rmodseg, RMOD_OFFSET_EXECPROG);`	400	`char far *rmod_execprog = MK_FP(rmod->rmodseg, RMOD_OFFSET_EXECPROG);`
402	`char far *rmod_cmdtail = MK_FP(rmod->rmodseg, 0x81);`	401	`char far *rmod_cmdtail = MK_FP(rmod->rmodseg, 0x81);`
403	`_Packed struct {`	402	`_Packed struct {`
404	`unsigned short envseg;`	403	`unsigned short envseg;`
405	`unsigned long cmdtail;`	404	`unsigned long cmdtail;`
406	`unsigned long fcb1;`	405	`unsigned long fcb1;`
407	`unsigned long fcb2;`	406	`unsigned long fcb2;`
408	`} far *ExecParam = MK_FP(rmod->rmodseg, RMOD_OFFSET_EXECPARAM);`	407	`} far *ExecParam = MK_FP(rmod->rmodseg, RMOD_OFFSET_EXECPARAM);`
409		408
410	`/* find cmd and cmdtail */`	409	`/* find cmd and cmdtail */`
411	`i = 0;`	410	`i = 0;`
412	`cmdtail = cmdline;`	411	`cmdtail = cmdline;`
413	`while (cmdtail == ' ') cmdtail++; / skip any leading spaces */`	412	`while (cmdtail == ' ') cmdtail++; / skip any leading spaces */`
414	`while ((cmdtail != ' ') && (cmdtail != '/') && (cmdtail != '+') && (cmdtail != 0)) {`	413	`while ((cmdtail != ' ') && (cmdtail != '/') && (cmdtail != '+') && (cmdtail != 0)) {`
415	`cmd[i++] = *cmdtail;`	414	`cmd[i++] = *cmdtail;`
416	`cmdtail++;`	415	`cmdtail++;`
417	`}`	416	`}`
418	`cmd[i] = 0;`	417	`cmd[i] = 0;`
419		418
420	`/* is this a command in curdir? */`	419	`/* is this a command in curdir? */`
421	`lookup = lookup_cmd(cmdfile, cmd, NULL, &ext);`	420	`lookup = lookup_cmd(cmdfile, cmd, NULL, &ext);`
422	`if (lookup == 0) {`	421	`if (lookup == 0) {`
423	`/* printf("FOUND LOCAL EXEC FILE: '%s'\r\n", cmdfile); */`	422	`/* printf("FOUND LOCAL EXEC FILE: '%s'\r\n", cmdfile); */`
424	`goto RUNCMDFILE;`	423	`goto RUNCMDFILE;`
425	`} else if (lookup == -2) {`	424	`} else if (lookup == -2) {`
426	`/* puts("NOT FOUND"); */`	425	`/* puts("NOT FOUND"); */`
427	`return;`	426	`return;`
428	`}`	427	`}`
429		428
430	`/* try matching something in PATH */`	429	`/* try matching something in PATH */`
431	`pathptr = env_lookup_val(envseg, "PATH");`	430	`pathptr = env_lookup_val(envseg, "PATH");`
432	`if (pathptr == NULL) return;`	431	`if (pathptr == NULL) return;`
433		432
434	`/* try each path in %PATH% */`	433	`/* try each path in %PATH% */`
435	`for (;;) {`	434	`for (;;) {`
436	`for (i = 0;; i++) {`	435	`for (i = 0;; i++) {`
437	`buff[i] = *pathptr;`	436	`buff[i] = *pathptr;`
438	`if ((buff[i] == 0) \|\| (buff[i] == ';')) break;`	437	`if ((buff[i] == 0) \|\| (buff[i] == ';')) break;`
439	`pathptr++;`	438	`pathptr++;`
440	`}`	439	`}`
441	`buff[i] = 0;`	440	`buff[i] = 0;`
442	`lookup = lookup_cmd(cmdfile, cmd, buff, &ext);`	441	`lookup = lookup_cmd(cmdfile, cmd, buff, &ext);`
443	`if (lookup == 0) break;`	442	`if (lookup == 0) break;`
444	`if (lookup == -2) return;`	443	`if (lookup == -2) return;`
445	`if (*pathptr == ';') {`	444	`if (*pathptr == ';') {`
446	`pathptr++;`	445	`pathptr++;`
447	`} else {`	446	`} else {`
448	`return;`	447	`return;`
449	`}`	448	`}`
450	`}`	449	`}`
451		450
452	`RUNCMDFILE:`	451	`RUNCMDFILE:`
453		452
454	`/* special handling of batch files */`	453	`/* special handling of batch files */`
455	`if ((ext != NULL) && (imatch(ext, "bat"))) {`	454	`if ((ext != NULL) && (imatch(ext, "bat"))) {`
456	`/* copy truename of the bat file to rmod buff */`	455	`/* copy truename of the bat file to rmod buff */`

Subversion Repositories SvarDOS

(root)/svarcom/tags/svarcom-2023.1/command.c @ 1203 – Rev 490 → 491