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 "env.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 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 '_':  /* $_ = CR+LF */
        *s = '\r';
        s++;
        *s = '\n';
        s++;
        break;
    }
  }
  *s = '$';
}
 
 
static void run_as_external(const char far *cmdline) {
  char buff[256];
  char const *argvlist[256];
  int i, n;
  /* copy buffer to a near var (incl. trailing CR), insert a space before
     every slash to make sure arguments are well separated */
  n = 0;
  i = 0;
  for (;;) {
    if (cmdline[i] == '/') buff[n++] = ' ';
    buff[n++] = cmdline[i++];
    if (buff[n] == 0) break;
  }
 
  cmd_explode(buff, cmdline, argvlist);
 
  /* for (i = 0; argvlist[i] != NULL; i++) printf("arg #%d = '%s'\r\n", i, argvlist[i]); */
 
  /* must be an external command then. this call should never return, unless
   * the other program failed to be executed. */
  execvp(argvlist[0], argvlist);
}
 
 
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);
}
 
 
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);
 
 
    }
    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);
 
  /* 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_seg, RMOD_OFFSET_INPBUFF, *rmod_envseg, envsiz);
  }
 
  for (;;) {
    char far *cmdline = MK_FP(rmod_seg, RMOD_OFFSET_INPBUFF + 2);
 
    /* revert input history terminator to \r */
    if (cmdline[-1] != 0) {
      cmdline[(unsigned short)(cmdline[-1])] = '\r';
    }
 
    {
      /* print shell prompt */
      char buff[256];
      char *promptptr = buff;
      buildprompt(promptptr, "$p$g"); /* TODO: prompt should be configurable via environment */
      _asm {
        push ax
        push dx
        mov ah, 0x09
        mov dx, promptptr
        int 0x21
        pop dx
        pop ax
      }
    }
 
    /* wait for user input */
    _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 */
      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
      pop dx
      pop cx
      pop bx
      pop ax
    }
    printf("\r\n");
 
    /* if nothing entered, loop again */
    if (cmdline[-1] == 0) continue;
 
    /* replace \r by a zero terminator */
    cmdline[(unsigned char)(cmdline[-1])] = 0;
 
    /* 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_seg, *rmod_envseg);
 
    /* try matching (and executing) an internal command */
    {
      int ecode = cmd_process(*rmod_envseg, cmdline);
      if (ecode >= 0) *lastexitcode = ecode;
 
 
 
 
 
 
 
 
 
 
      if (ecode >= -1) continue; /* internal command executed */
    }
 
    /* if here, then this was not an internal command */
    run_as_external(cmdline);
 
    /* 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);
}
 

Rev 366	Rev 367
1	`/*`	1	`/*`
2	`* SvarCOM is a command-line interpreter.`	2	`* SvarCOM is a command-line interpreter.`
3	`*`	3	`*`
4	`* a little memory area is allocated as high as possible. it contains:`	4	`* a little memory area is allocated as high as possible. it contains:`
5	`* - a signature (like XMS drivers do)`	5	`* - a signature (like XMS drivers do)`
6	`* - a routine for exec'ing programs`	6	`* - a routine for exec'ing programs`
7	`* - a "last command" buffer for input history`	7	`* - a "last command" buffer for input history`
8	`*`	8	`*`
9	`* when svarcom starts, it tries locating the routine in memory.`	9	`* when svarcom starts, it tries locating the routine in memory.`
10	`*`	10	`*`
11	`* if found:`	11	`* if found:`
12	`* waits for user input and processes it. if execing something is required, set the "next exec" field in routine's memory and quit.`	12	`* waits for user input and processes it. if execing something is required, set the "next exec" field in routine's memory and quit.`
13	`*`	13	`*`
14	`* if not found:`	14	`* if not found:`
15	`* installs it by creating a new PSP, set int 22 vector to the routine, set my "parent PSP" to the routine`	15	`* installs it by creating a new PSP, set int 22 vector to the routine, set my "parent PSP" to the routine`
16	`* and quit.`	16	`* and quit.`
17	`*`	17	`*`
18	`*`	18	`*`
19	`*`	19	`*`
20	`* good lecture about PSP and allocating memory`	20	`* good lecture about PSP and allocating memory`
21	`* https://retrocomputing.stackexchange.com/questions/20001/how-much-of-the-program-segment-prefix-area-can-be-reused-by-programs-with-impun/20006#20006`	21	`* https://retrocomputing.stackexchange.com/questions/20001/how-much-of-the-program-segment-prefix-area-can-be-reused-by-programs-with-impun/20006#20006`
22	`*`	22	`*`
23	`* PSP structure`	23	`* PSP structure`
24	`* http://www.piclist.com/techref/dos/psps.htm`	24	`* http://www.piclist.com/techref/dos/psps.htm`
25	`*`	25	`*`
26	`*`	26	`*`
27	`*`	27	`*`
28	`* === MCB ===`	28	`* === MCB ===`
29	`*`	29	`*`
30	`* each time that DOS allocates memory, it prefixes the allocated memory with`	30	`* each time that DOS allocates memory, it prefixes the allocated memory with`
31	`* a 16-bytes structure called a "Memory Control Block" (MCB). This control`	31	`* a 16-bytes structure called a "Memory Control Block" (MCB). This control`
32	`* block has the following structure:`	32	`* block has the following structure:`
33	`*`	33	`*`
34	`* Offset Size Description`	34	`* Offset Size Description`
35	`* 00h byte 'M' = non-last member of the MCB chain`	35	`* 00h byte 'M' = non-last member of the MCB chain`
36	`* 'Z' = indicates last entry in MCB chain`	36	`* 'Z' = indicates last entry in MCB chain`
37	`* other values cause "Memory Allocation Failure" on exit`	37	`* other values cause "Memory Allocation Failure" on exit`
38	`* 01h word PSP segment address of the owner (Process Id)`	38	`* 01h word PSP segment address of the owner (Process Id)`
39	`* possible values:`	39	`* possible values:`
40	`* 0 = free`	40	`* 0 = free`
41	`* 8 = Allocated by DOS before first user pgm loaded`	41	`* 8 = Allocated by DOS before first user pgm loaded`
42	`* other = Process Id/PSP segment address of owner`	42	`* other = Process Id/PSP segment address of owner`
43	`* 03h word number of paragraphs related to this MCB (excluding MCB)`	43	`* 03h word number of paragraphs related to this MCB (excluding MCB)`
44	`* 05h 11 bytes reserved`	44	`* 05h 11 bytes reserved`
45	`* 10h ... start of actual allocated memory block`	45	`* 10h ... start of actual allocated memory block`
46	`*/`	46	`*/`
47		47
48	`#include <i86.h>`	48	`#include <i86.h>`
49	`#include <dos.h>`	49	`#include <dos.h>`
50	`#include <stdio.h>`	50	`#include <stdio.h>`
51	`#include <stdlib.h>`	51	`#include <stdlib.h>`
52	`#include <string.h>`	52	`#include <string.h>`
53		53
54	`#include <process.h>`	54	`#include <process.h>`
55		55
56	`#include "cmd.h"`	56	`#include "cmd.h"`
57	`#include "env.h"`	57	`#include "env.h"`
58	`#include "helpers.h"`	58	`#include "helpers.h"`
59	`#include "rmodinit.h"`	59	`#include "rmodinit.h"`
60		60
61	`struct config {`	61	`struct config {`
62	`int locate;`	62	`int locate;`
63	`int install;`	63	`int install;`
64	`int envsiz;`	64	`int envsiz;`
65	`} cfg;`	65	`} cfg;`
66		66
67		67
68	`static void parse_argv(struct config cfg, int argc, char *argv) {`	68	`static void parse_argv(struct config cfg, int argc, char *argv) {`
69	`int i;`	69	`int i;`
70	`memset(cfg, 0, sizeof(*cfg));`	70	`memset(cfg, 0, sizeof(*cfg));`
71		71
72	`for (i = 1; i < argc; i++) {`	72	`for (i = 1; i < argc; i++) {`
73	`if (strcmp(argv[i], "/locate") == 0) {`	73	`if (strcmp(argv[i], "/locate") == 0) {`
74	`cfg->locate = 1;`	74	`cfg->locate = 1;`
75	`}`	75	`}`
76	`if (strstartswith(argv[i], "/e:") == 0) {`	76	`if (strstartswith(argv[i], "/e:") == 0) {`
77	`cfg->envsiz = atoi(argv[i]+3);`	77	`cfg->envsiz = atoi(argv[i]+3);`
78	`if (cfg->envsiz < 64) cfg->envsiz = 0;`	78	`if (cfg->envsiz < 64) cfg->envsiz = 0;`
79	`}`	79	`}`
80	`}`	80	`}`
81	`}`	81	`}`
82		82
83		83
84	`static void buildprompt(char s, const char fmt) {`	84	`static void buildprompt(char s, const char fmt) {`
85	`for (; *fmt != 0; fmt++) {`	85	`for (; *fmt != 0; fmt++) {`
86	`if (*fmt != '$') {`	86	`if (*fmt != '$') {`
87	`s = fmt;`	87	`s = fmt;`
88	`s++;`	88	`s++;`
89	`continue;`	89	`continue;`
90	`}`	90	`}`
91	`/* escape code ($P, etc) */`	91	`/* escape code ($P, etc) */`
92	`fmt++;`	92	`fmt++;`
93	`switch (*fmt) {`	93	`switch (*fmt) {`
94	`case 'Q': /* $Q = = (equal sign) */`	94	`case 'Q': /* $Q = = (equal sign) */`
95	`case 'q':`	95	`case 'q':`
96	`*s = '=';`	96	`*s = '=';`
97	`s++;`	97	`s++;`
98	`break;`	98	`break;`
99	`case '$': /* $$ = $ (dollar sign) */`	99	`case '$': /* $$ = $ (dollar sign) */`
100	`*s = '$';`	100	`*s = '$';`
101	`s++;`	101	`s++;`
102	`break;`	102	`break;`
103	`case 'T': /* $t = current time */`	103	`case 'T': /* $t = current time */`
104	`case 't':`	104	`case 't':`
105	`s += sprintf(s, "00:00"); /* TODO */`	105	`s += sprintf(s, "00:00"); /* TODO */`
106	`break;`	106	`break;`
107	`case 'D': /* $D = current date */`	107	`case 'D': /* $D = current date */`
108	`case 'd':`	108	`case 'd':`
109	`s += sprintf(s, "1985-07-29"); /* TODO */`	109	`s += sprintf(s, "1985-07-29"); /* TODO */`
110	`break;`	110	`break;`
111	`case 'P': /* $P = current drive and path */`	111	`case 'P': /* $P = current drive and path */`
112	`case 'p':`	112	`case 'p':`
113	`_asm {`	113	`_asm {`
114	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`	114	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`
115	`int 0x21`	115	`int 0x21`
116	`mov bx, s`	116	`mov bx, s`
117	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`	117	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`
118	`}`	118	`}`
119	`*s += 'A';`	119	`*s += 'A';`
120	`s++;`	120	`s++;`
121	`*s = ':';`	121	`*s = ':';`
122	`s++;`	122	`s++;`
123	`*s = '\\';`	123	`*s = '\\';`
124	`s++;`	124	`s++;`
125	`_asm {`	125	`_asm {`
126	`mov ah, 0x47 /* DOS 2+ - CWD - GET CURRENT DIRECTORY */`	126	`mov ah, 0x47 /* DOS 2+ - CWD - GET CURRENT DIRECTORY */`
127	`xor dl,dl /* DL = drive number (00h = default, 01h = A:, etc) */`	127	`xor dl,dl /* DL = drive number (00h = default, 01h = A:, etc) */`
128	`mov si, s /* DS:SI -> 64-byte buffer for ASCIZ pathname */`	128	`mov si, s /* DS:SI -> 64-byte buffer for ASCIZ pathname */`
129	`int 0x21`	129	`int 0x21`
130	`}`	130	`}`
131	`while (s != 0) s++; / move ptr forward to end of pathname */`	131	`while (s != 0) s++; / move ptr forward to end of pathname */`
132	`break;`	132	`break;`
133	`case 'V': /* $V = DOS version number */`	133	`case 'V': /* $V = DOS version number */`
134	`case 'v':`	134	`case 'v':`
135	`s += sprintf(s, "VER"); /* TODO */`	135	`s += sprintf(s, "VER"); /* TODO */`
136	`break;`	136	`break;`
137	`case 'N': /* $N = current drive */`	137	`case 'N': /* $N = current drive */`
138	`case 'n':`	138	`case 'n':`
139	`_asm {`	139	`_asm {`
140	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`	140	`mov ah, 0x19 /* DOS 1+ - GET CURRENT DRIVE */`
141	`int 0x21`	141	`int 0x21`
142	`mov bx, s`	142	`mov bx, s`
143	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`	143	`mov [bx], al /* AL = drive (00 = A:, 01 = B:, etc */`
144	`}`	144	`}`
145	`*s += 'A';`	145	`*s += 'A';`
146	`s++;`	146	`s++;`
147	`break;`	147	`break;`
148	`case 'G': /* $G = > (greater-than sign) */`	148	`case 'G': /* $G = > (greater-than sign) */`
149	`case 'g':`	149	`case 'g':`
150	`*s = '>';`	150	`*s = '>';`
151	`s++;`	151	`s++;`
152	`break;`	152	`break;`
153	`case 'L': /* $L = < (less-than sign) */`	153	`case 'L': /* $L = < (less-than sign) */`
154	`case 'l':`	154	`case 'l':`
155	`*s = '<';`	155	`*s = '<';`
156	`s++;`	156	`s++;`
157	`break;`	157	`break;`
158	`case 'B': /* $B = \| (pipe) */`	158	`case 'B': /* $B = \| (pipe) */`
159	`case 'b':`	159	`case 'b':`
160	`*s = '\|';`	160	`*s = '\|';`
161	`s++;`	161	`s++;`
162	`break;`	162	`break;`
163	`case 'H': /* $H = backspace (erases previous character) */`	163	`case 'H': /* $H = backspace (erases previous character) */`
164	`case 'h':`	164	`case 'h':`
165	`*s = '\b';`	165	`*s = '\b';`
166	`s++;`	166	`s++;`
167	`break;`	167	`break;`
168	`case 'E': /* $E = Escape code (ASCII 27) */`	168	`case 'E': /* $E = Escape code (ASCII 27) */`
169	`case 'e':`	169	`case 'e':`
170	`*s = 27;`	170	`*s = 27;`
171	`s++;`	171	`s++;`
172	`break;`	172	`break;`
173	`case '_': /* $_ = CR+LF */`	173	`case '_': /* $_ = CR+LF */`
174	`*s = '\r';`	174	`*s = '\r';`
175	`s++;`	175	`s++;`
176	`*s = '\n';`	176	`*s = '\n';`
177	`s++;`	177	`s++;`
178	`break;`	178	`break;`
179	`}`	179	`}`
180	`}`	180	`}`
181	`*s = '$';`	181	`*s = '$';`
182	`}`	182	`}`
183		183
184		184
185	`static void run_as_external(const char far *cmdline) {`	185	`static void run_as_external(const char far *cmdline) {`
186	`char buff[256];`	186	`char buff[256];`
187	`char const *argvlist[256];`	187	`char const *argvlist[256];`
188	`int i, n;`	188	`int i, n;`
189	`/* copy buffer to a near var (incl. trailing CR), insert a space before`	189	`/* copy buffer to a near var (incl. trailing CR), insert a space before`
190	`every slash to make sure arguments are well separated */`	190	`every slash to make sure arguments are well separated */`
191	`n = 0;`	191	`n = 0;`
192	`i = 0;`	192	`i = 0;`
193	`for (;;) {`	193	`for (;;) {`
194	`if (cmdline[i] == '/') buff[n++] = ' ';`	194	`if (cmdline[i] == '/') buff[n++] = ' ';`
195	`buff[n++] = cmdline[i++];`	195	`buff[n++] = cmdline[i++];`
196	`if (buff[n] == 0) break;`	196	`if (buff[n] == 0) break;`
197	`}`	197	`}`
198		198
199	`cmd_explode(buff, cmdline, argvlist);`	199	`cmd_explode(buff, cmdline, argvlist);`
200		200
201	`/* for (i = 0; argvlist[i] != NULL; i++) printf("arg #%d = '%s'\r\n", i, argvlist[i]); */`	201	`/* for (i = 0; argvlist[i] != NULL; i++) printf("arg #%d = '%s'\r\n", i, argvlist[i]); */`
202		202
203	`/* must be an external command then. this call should never return, unless`	203	`/* must be an external command then. this call should never return, unless`
204	`* the other program failed to be executed. */`	204	`* the other program failed to be executed. */`
205	`execvp(argvlist[0], argvlist);`	205	`execvp(argvlist[0], argvlist);`
206	`}`	206	`}`
207		207
208		208
-		209	`static void set_comspec_to_self(unsigned short envseg) {`
-		210	`unsigned short psp_envseg = (void )(0x2c); /* pointer to my env segment field in the PSP */`
-		211	`char far myenv = MK_FP(psp_envseg, 0);`
-		212	`unsigned short varcount;`
-		213	`char buff[256] = "COMSPEC=";`
-		214	`char *buffptr = buff + 8;`
-		215	`/* who am i? look into my own environment, at the end of it should be my EXEPATH string */`
-		216	`while (*myenv != 0) {`
-		217	`/* consume a NULL-terminated string */`
-		218	`while (*myenv != 0) myenv++;`
-		219	`/* move to next string */`
-		220	`myenv++;`
-		221	`}`
-		222	`/* get next word, if 1 then EXEPATH follows */`
-		223	`myenv++;`
-		224	`varcount = *myenv;`
-		225	`myenv++;`
-		226	`varcount \|= (*myenv << 8);`
-		227	`myenv++;`
-		228	`if (varcount != 1) return; /* NO EXEPATH FOUND */`
-		229	`while (*myenv != 0) {`
-		230	`buffptr = myenv;`
-		231	`buffptr++;`
-		232	`myenv++;`
-		233	`}`
-		234	`*buffptr = 0;`
-		235	`/* printf("EXEPATH: '%s'\r\n", buff); */`
-		236	`env_setvar(envseg, buff);`
-		237	`}`
-		238
-		239
209	`int main(int argc, char **argv) {`	240	`int main(int argc, char **argv) {`
210	`struct config cfg;`	241	`struct config cfg;`
211	`unsigned short rmod_seg;`	242	`unsigned short rmod_seg;`
212	`unsigned short far *rmod_envseg;`	243	`unsigned short far *rmod_envseg;`
213	`unsigned short far *lastexitcode;`	244	`unsigned short far *lastexitcode;`
214		245
215	`parse_argv(&cfg, argc, argv);`	246	`parse_argv(&cfg, argc, argv);`
216		247
217	`rmod_seg = rmod_find();`	248	`rmod_seg = rmod_find();`
218	`if (rmod_seg == 0xffff) {`	249	`if (rmod_seg == 0xffff) {`
219	`rmod_seg = rmod_install(cfg.envsiz);`	250	`rmod_seg = rmod_install(cfg.envsiz);`
220	`if (rmod_seg == 0xffff) {`	251	`if (rmod_seg == 0xffff) {`
221	`puts("ERROR: rmod_install() failed");`	252	`puts("ERROR: rmod_install() failed");`
222	`return(1);`	253	`return(1);`
223	`} else {`	-
224	`printf("rmod installed at seg 0x%04X\r\n", rmod_seg);`	-
225	`}`	254	`}`
-		255	`printf("rmod installed at seg 0x%04X\r\n", rmod_seg);`
226	`} else {`	256	`} else {`
227	`printf("rmod found at seg 0x%04x\r\n", rmod_seg);`	257	`printf("rmod found at seg 0x%04x\r\n", rmod_seg);`
228	`}`	258	`}`
229		259
230	`rmod_envseg = MK_FP(rmod_seg, RMOD_OFFSET_ENVSEG);`	260	`rmod_envseg = MK_FP(rmod_seg, RMOD_OFFSET_ENVSEG);`
231	`lastexitcode = MK_FP(rmod_seg, RMOD_OFFSET_LEXITCODE);`	261	`lastexitcode = MK_FP(rmod_seg, RMOD_OFFSET_LEXITCODE);`
232		262
-		263	`/* make COMPSEC point to myself */`
-		264	`set_comspec_to_self(*rmod_envseg);`
-		265
233	`{`	266	`{`
234	`unsigned short envsiz;`	267	`unsigned short envsiz;`
235	`unsigned short far sizptr = MK_FP(rmod_envseg - 1, 3);`	268	`unsigned short far sizptr = MK_FP(rmod_envseg - 1, 3);`
236	`envsiz = *sizptr;`	269	`envsiz = *sizptr;`
237	`envsiz *= 16;`	270	`envsiz *= 16;`
238	`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);`	271	`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);`
239	`}`	272	`}`
240		273
241	`for (;;) {`	274	`for (;;) {`
242	`char far *cmdline = MK_FP(rmod_seg, RMOD_OFFSET_INPBUFF + 2);`	275	`char far *cmdline = MK_FP(rmod_seg, RMOD_OFFSET_INPBUFF + 2);`
243		276
244	`/* revert input history terminator to \r */`	277	`/* revert input history terminator to \r */`
245	`if (cmdline[-1] != 0) {`	278	`if (cmdline[-1] != 0) {`
246	`cmdline[(unsigned short)(cmdline[-1])] = '\r';`	279	`cmdline[(unsigned short)(cmdline[-1])] = '\r';`
247	`}`	280	`}`
248		281
249	`{`	282	`{`
250	`/* print shell prompt */`	283	`/* print shell prompt */`
251	`char buff[256];`	284	`char buff[256];`
252	`char *promptptr = buff;`	285	`char *promptptr = buff;`
253	`buildprompt(promptptr, "$p$g"); /* TODO: prompt should be configurable via environment */`	286	`buildprompt(promptptr, "$p$g"); /* TODO: prompt should be configurable via environment */`
254	`_asm {`	287	`_asm {`
255	`push ax`	288	`push ax`
256	`push dx`	289	`push dx`
257	`mov ah, 0x09`	290	`mov ah, 0x09`
258	`mov dx, promptptr`	291	`mov dx, promptptr`
259	`int 0x21`	292	`int 0x21`
260	`pop dx`	293	`pop dx`
261	`pop ax`	294	`pop ax`
262	`}`	295	`}`
263	`}`	296	`}`
264		297
265	`/* wait for user input */`	298	`/* wait for user input */`
266	`_asm {`	299	`_asm {`
267	`push ax`	300	`push ax`
268	`push bx`	301	`push bx`
269	`push cx`	302	`push cx`
270	`push dx`	303	`push dx`
271	`push ds`	304	`push ds`
272		305
273	`/* is DOSKEY support present? (INT 2Fh, AX=4800h, returns non-zero in AL if present) */`	306	`/* is DOSKEY support present? (INT 2Fh, AX=4800h, returns non-zero in AL if present) */`
274	`mov ax, 0x4800`	307	`mov ax, 0x4800`
275	`int 0x2f`	308	`int 0x2f`
276	`mov bl, al /* save doskey status in BL */`	309	`mov bl, al /* save doskey status in BL */`
277		310
278	`/* set up buffered input */`	311	`/* set up buffered input */`
279	`mov ax, rmod_seg`	312	`mov ax, rmod_seg`
280	`push ax`	313	`push ax`
281	`pop ds`	314	`pop ds`
282	`mov dx, RMOD_OFFSET_INPBUFF`	315	`mov dx, RMOD_OFFSET_INPBUFF`
283		316
284	`/* execute either DOS input or DOSKEY */`	317	`/* execute either DOS input or DOSKEY */`
285	`test bl, bl /* zf set if no DOSKEY present */`	318	`test bl, bl /* zf set if no DOSKEY present */`
286	`jnz DOSKEY`	319	`jnz DOSKEY`
287		320
288	`mov ah, 0x0a`	321	`mov ah, 0x0a`
289	`int 0x21`	322	`int 0x21`
290	`jmp short DONE`	323	`jmp short DONE`
291		324
292	`DOSKEY:`	325	`DOSKEY:`
293	`mov ax, 0x4810`	326	`mov ax, 0x4810`
294	`int 0x2f`	327	`int 0x2f`
295		328
296	`DONE:`	329	`DONE:`
297	`pop ds`	330	`pop ds`
298	`pop dx`	331	`pop dx`
299	`pop cx`	332	`pop cx`
300	`pop bx`	333	`pop bx`
301	`pop ax`	334	`pop ax`
302	`}`	335	`}`
303	`printf("\r\n");`	336	`printf("\r\n");`
304		337
305	`/* if nothing entered, loop again */`	338	`/* if nothing entered, loop again */`
306	`if (cmdline[-1] == 0) continue;`	339	`if (cmdline[-1] == 0) continue;`
307		340
308	`/* replace \r by a zero terminator */`	341	`/* replace \r by a zero terminator */`
309	`cmdline[(unsigned char)(cmdline[-1])] = 0;`	342	`cmdline[(unsigned char)(cmdline[-1])] = 0;`
310		343
311	`/* move pointer forward to skip over any leading spaces */`	344	`/* move pointer forward to skip over any leading spaces */`
312	`while (*cmdline == ' ') cmdline++;`	345	`while (*cmdline == ' ') cmdline++;`
313		346
-		347	`/* update rmod's ptr to COMPSPEC so it is always up to date */`
-		348	`rmod_updatecomspecptr(rmod_seg, *rmod_envseg);`
-		349
314	`/* try matching (and executing) an internal command */`	350	`/* try matching (and executing) an internal command */`
315	`{`	351	`{`
316	`int ecode = cmd_process(*rmod_envseg, cmdline);`	352	`int ecode = cmd_process(*rmod_envseg, cmdline);`
317	`if (ecode >= 0) *lastexitcode = ecode;`	353	`if (ecode >= 0) *lastexitcode = ecode;`
318	`/* update rmod's ptr to COMPSPEC, in case it changed */`	-
319	`{`	-
320	`unsigned short far *comspecptr = MK_FP(rmod_seg, RMOD_OFFSET_COMSPECPTR);`	-
321	`char far comspecfp = env_lookup(rmod_envseg, "COMSPEC");`	-
322	`if (comspecfp != NULL) {`	-
323	`comspecptr = FP_OFF(comspecfp) + 8; / +8 to skip the "COMSPEC=" prefix */`	-
324	`} else {`	-
325	`*comspecptr = 0;`	-
326	`}`	-
327	`}`	-
328	`if (ecode >= -1) continue; /* internal command executed */`	354	`if (ecode >= -1) continue; /* internal command executed */`
329	`}`	355	`}`
330		356
331	`/* if here, then this was not an internal command */`	357	`/* if here, then this was not an internal command */`
332	`run_as_external(cmdline);`	358	`run_as_external(cmdline);`
333		359
334	`/* execvp() replaces the current process by the new one`	360	`/* execvp() replaces the current process by the new one`
335	`if I am still alive then external command failed to execute */`	361	`if I am still alive then external command failed to execute */`
336	`puts("Bad command or file name");`	362	`puts("Bad command or file name");`
337		363
338	`}`	364	`}`
339		365
340	`return(0);`	366	`return(0);`
341	`}`	367	`}`
342		368

Subversion Repositories SvarDOS

(root)/svarcom/trunk/command.c @ 1202 – Rev 366 → 367