WebSVN – SvarDOS – Diff – /svarcom/trunk/command.c

 /*
  * 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.
+ *
+ *
+ *
  * good lecture about PSP and allocating memory
  * https://retrocomputing.stackexchange.com/questions/20001/how-much-of-the-program-segment-prefix-area-can-be-reused-by-programs-with-impun/20006#20006
+ *
  * 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 "helpers.h"
 #include "rmodinit.h"
 struct config {
   int locate;
   int install;
   int envsiz;
 } cfg;
 static void parse_argv(struct config *cfg, int argc, char **argv) {
   int i;
   memset(cfg, 0, sizeof(*cfg));
   for (i = 1; i < argc; i++) {
     if (strcmp(argv[i], "/locate") == 0) {
       cfg->locate = 1;
+    }
     if (strstartswith(argv[i], "/e:") == 0) {
       cfg->envsiz = atoi(argv[i]+3);
       if (cfg->envsiz < 64) cfg->envsiz = 0;
+    }
+  }
+}
 static int explode_progparams(char *s, char const **argvlist) {
   int si = 0, argc = 0;
   for (;;) {
     /* skip to next non-space character */
     while (s[si] == ' ') si++;
     /* end of string? */
     if (s[si] == '\r') break;
     /* set argv ptr */
     argvlist[argc++] = s + si;
     /* find next space */
     while (s[si] != ' ' && s[si] != '\r') si++;
     /* is this end of string? */
     if (s[si] == '\r') {
       s[si] = 0;
       break;
+    }
     /* not end: terminate arg and look for next one */
     s[si++] = 0;
+  }
   /* terminate argvlist with a NULL value */
   argvlist[argc] = NULL;
   return(argc);
+}
+static void buildprompt(char *s, const char *fmt) {
+  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 '_':  /* $_ = CR+LF */
+        *s = '\r';
+        s++;
+        *s = '\n';
+        s++;
+        break;
+    }
+  }
+  *s = '$';
+}
 int main(int argc, char **argv) {
   struct config cfg;
   unsigned short rmod_seg;
   unsigned short far *rmod_envseg;
   unsigned short far *lastexitcode;
   parse_argv(&cfg, argc, argv);
   rmod_seg = rmod_find();
   if (rmod_seg == 0xffff) {
     rmod_seg = rmod_install(cfg.envsiz);
     if (rmod_seg == 0xffff) {
       puts("ERROR: rmod_install() failed");
       return(1);
     } else {
       printf("rmod installed at seg 0x%04X\r\n", rmod_seg);
+    }
   } else {
     printf("rmod found at seg 0x%04x\r\n", rmod_seg);
+  }
   rmod_envseg = MK_FP(rmod_seg, RMOD_OFFSET_ENVSEG);
   lastexitcode = MK_FP(rmod_seg, RMOD_OFFSET_LEXITCODE);
+  {
     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_seg, RMOD_OFFSET_INPBUFF, *rmod_envseg, envsiz);
+  }
   for (;;) {
     int i, argcount;
     char far *cmdline = MK_FP(rmod_seg, RMOD_OFFSET_INPBUFF + 2);
-    char path[256] = "C:\\>$";
+    char buff[256];
     char const *argvlist[256];
-    union REGS r;
+    {
-    /* print shell prompt */
+      /* print shell prompt */
+      char *promptptr = buff;
+      buildprompt(promptptr, "$p$g"); /* TODO: prompt should be configurable via environment */
+      _asm {
+        push dx
-    r.h.ah = 0x09;
+        mov ah, 0x09
-    r.x.dx = FP_OFF(path);
+        mov dx, promptptr
-    intdos(&r, &r);
+        int 0x21
+        pop dx
+      }
+    }
     /* wait for user input */
     _asm {
       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 */
       mov ax, rmod_seg
       push ax
       pop ds
       mov dx, RMOD_OFFSET_INPBUFF
       /* 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:
       pop ds
+    }
     printf("\r\n");
     /* if nothing entered, loop again */
     if (cmdline[-1] == 0) continue;
     /* copy buffer to a near var (incl. trailing CR) */
-    _fmemcpy(path, cmdline, cmdline[-1] + 1);
+    _fmemcpy(buff, cmdline, cmdline[-1] + 1);
-    argcount = explode_progparams(path, argvlist);
+    argcount = explode_progparams(buff, argvlist);
     /* if nothing args found (eg. all-spaces), loop again */
     if (argcount == 0) continue;
     printf("got %u bytes of cmdline (%d args)\r\n", cmdline[-1], argcount);
     for (i = 0; i < argcount; i++) {
       printf("arg #%d = '%s'\r\n", i, argvlist[i]);
+    }
     /* is it about quitting? */
     if (imatch(argvlist[0], "exit")) break;
     /* try running it as an internal command */
+    {
       int ecode = cmd_process(argcount, argvlist, *rmod_envseg);
       if (ecode >= 0) *lastexitcode = ecode;
       if (ecode >= -1) continue; /* command is internal but did not set an exit code */
+    }
     /* must be an external command then */
     execvp(argvlist[0], argvlist);
     /* execvp() replaces the current process by the new one
     if I am still alive then external command failed to execute */
     puts("Bad command or file name");
+  }
   return(0);
+}

Subversion Repositories SvarDOS

(root)/svarcom/trunk/command.c @ 1087 – Rev 353 → 354