/svarcom/command.c |
---|
48,7 → 48,6 |
#include <i86.h> |
#include <dos.h> |
#include <stdio.h> |
#include <stdlib.h> |
#include <string.h> |
#include <process.h> |
58,41 → 57,16 |
struct config { |
int locate; |
int install; |
int envsiz; |
} cfg; |
#define RMOD_OFFSET_ENVSEG 0x08 |
#define RMOD_OFFSET_INPBUFF 0x0A |
#define RMOD_OFFSET_ROUTINE 0x8C |
/* returns segment where rmod is installed */ |
unsigned short rmod_install(unsigned short envsize) { |
char far *myptr, far *mcb; |
unsigned short install_routine(void) { |
char far *ptr, far *mcb; |
unsigned short far *owner; |
unsigned int rmodseg = 0xffff; |
unsigned int envseg = 0; |
unsigned int memseg = 0xffff; |
/* read my current env segment from PSP */ |
_asm { |
push ax |
push bx |
mov bx, 0x2c |
mov ax, [bx] |
mov envseg, ax |
pop bx |
pop ax |
} |
printf("original (PSP) env buffer at %04X\r\n", envseg); |
/* if custom envsize requested, convert it to number of paragraphs */ |
if (envsize != 0) { |
envsize += 15; |
envsize /= 16; |
} |
_asm { |
/* link in the UMB memory chain for enabling high-memory allocation (and save initial status on stack) */ |
mov ax, 0x5802 /* GET UMB LINK STATE */ |
int 0x21 |
110,21 → 84,12 |
mov ax, 0x5801 |
mov bx, 0x0082 |
int 0x21 |
/* ask for a memory block and save the given segment to rmodseg */ |
/* ask for a memory block and save the given segment to memseg */ |
mov ah, 0x48 |
mov bx, (rmod_len + 15) / 16 |
int 0x21 |
jc ALLOC_FAIL |
mov rmodseg, ax |
/* ask for a memory block for the environment and save it to envseg (only if custom size requested) */ |
mov bx, envsize |
test bx, bx |
jz ALLOC_FAIL |
mov ah, 0x48 |
int 0x21 |
jc ALLOC_FAIL |
mov envseg, ax |
mov memseg, ax |
ALLOC_FAIL: |
/* restore initial allocation strategy */ |
mov ax, 0x5801 |
136,35 → 101,15 |
int 0x21 |
} |
if (rmodseg == 0xffff) { |
if (memseg == 0xffff) { |
puts("malloc error"); |
return(0xffff); |
} |
/* copy rmod to its destination */ |
myptr = MK_FP(rmodseg, 0); |
_fmemcpy(myptr, rmod, rmod_len); |
/* mark rmod memory as "self owned" */ |
mcb = MK_FP(rmodseg - 1, 0); |
ptr = MK_FP(memseg, 0); |
mcb = MK_FP(memseg - 1, 0); |
owner = (void far *)(mcb + 1); |
*owner = rmodseg; |
_fmemcpy(mcb + 8, "SVARCOM", 8); |
_fmemcpy(ptr, rmod, rmod_len); |
/* mark env memory as "self owned" (only if allocated by me) */ |
if (envsize != 0) { |
printf("envseg allocated at %04X:0000 with %u paragraphs\r\n", envseg, envsize); |
mcb = MK_FP(envseg - 1, 0); |
owner = (void far *)(mcb + 1); |
*owner = rmodseg; |
_fmemcpy(mcb + 8, "SVARENV", 8); |
} |
/* write env segment to rmod buffer */ |
owner = MK_FP(rmodseg, RMOD_OFFSET_ENVSEG); |
*owner = envseg; |
/* |
printf("MCB sig: %c\r\nMCB owner: 0x%04X\r\n", mcb[0], *owner); |
{ |
int i; |
180,41 → 125,28 |
} |
} |
printf("\r\n"); |
}*/ |
return(rmodseg); |
} |
/* returns zero if s1 starts with s2 */ |
static int strstartswith(const char *s1, const char *s2) { |
while (*s2 != 0) { |
if (*s1 != *s2) return(-1); |
s1++; |
s2++; |
/* mark memory as "self owned" */ |
*owner = memseg; |
_fmemcpy(mcb + 8, "COMMAND", 8); |
return(memseg); |
} |
return(0); |
} |
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; |
} |
} |
} |
/* scan memory for my shared buffer, return segment of buffer */ |
static unsigned short rmod_find(void) { |
static unsigned short find_shm(void) { |
unsigned short i; |
unsigned short far *pattern; |
221,10 → 153,10 |
/* iterate over all paragraphs, looking for my signature */ |
for (i = 0; i != 65535; i++) { |
pattern = MK_FP(i, 0); |
if (pattern[0] != 0x1983) continue; |
if (pattern[1] != 0x1985) continue; |
if (pattern[2] != 0x2017) continue; |
if (pattern[3] != 0x2019) continue; |
if (pattern[1] != 0x1983) continue; |
if (pattern[2] != 0x1985) continue; |
if (pattern[3] != 0x2017) continue; |
if (pattern[4] != 0x2019) continue; |
return(i); |
} |
return(0xffff); |
274,16 → 206,16 |
int main(int argc, char **argv) { |
struct config cfg; |
unsigned short rmod_seg; |
unsigned short far *rmod_envseg; |
unsigned short env_seg = 0, rmod_seg, rmod_buff = 0; |
void far *rmod_func; |
parse_argv(&cfg, argc, argv); |
rmod_seg = rmod_find(); |
rmod_seg = find_shm(); |
if (rmod_seg == 0xffff) { |
rmod_seg = rmod_install(cfg.envsiz); |
rmod_seg = install_routine(); |
if (rmod_seg == 0xffff) { |
puts("ERROR: rmod_install() failed"); |
puts("ERROR: install_rmod() failed"); |
return(1); |
} else { |
printf("rmod installed at seg 0x%04X\r\n", rmod_seg); |
292,16 → 224,15 |
printf("rmod found at seg 0x%04x\r\n", rmod_seg); |
} |
rmod_envseg = MK_FP(rmod_seg, RMOD_OFFSET_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); |
rmod_func = MK_FP(rmod_seg, 0x0A); |
/* fetch offset of buffer (result in AX) */ |
_asm { |
call dword ptr [rmod_func] |
mov rmod_buff, ax |
} |
printf("rmod_buff at %04X:%04X\r\n", rmod_seg, rmod_buff); |
_asm { |
/* set the int22 handler in my PSP to rmod so DOS jumps to rmod after I terminate */ |
mov bx, 0x0a |
309,11 → 240,17 |
mov [bx], ax |
mov ax, rmod_seg |
mov [bx+2], ax |
/* get the segment of my environment */ |
mov bx, 0x2c |
mov ax, [bx] |
mov env_seg, ax |
} |
printf("env_seg at %04X\r\n", env_seg); |
for (;;) { |
int i, argcount; |
char far *cmdline = MK_FP(rmod_seg, RMOD_OFFSET_INPBUFF + 2); |
char far *cmdline = MK_FP(rmod_seg, rmod_buff + 2); |
char path[256] = "C:\\>$"; |
char const *argvlist[256]; |
union REGS r; |
336,7 → 273,7 |
mov ax, rmod_seg |
push ax |
pop ds |
mov dx, RMOD_OFFSET_INPBUFF |
mov dx, rmod_buff |
/* execute either DOS input or DOSKEY */ |
test bl, bl /* zf set if no DOSKEY present */ |
373,7 → 310,7 |
/* TODO is it an internal command? */ |
if (strcmp(argvlist[0], "set") == 0) { |
cmd_set(argcount, argvlist, *rmod_envseg); |
cmd_set(argcount, argvlist, env_seg); |
continue; |
} |
/svarcom/rmod.asm |
---|
13,23 → 13,23 |
section .text ; all goes into code segment |
; offset |
SIG1 dw 0x1983 ; +0 |
SIG2 dw 0x1985 ; +2 |
SIG3 dw 0x2017 ; +4 |
SIG4 dw 0x2019 ; +6 |
jmp short skipsig |
; environment segment - this is updated by SvarCOM at init time |
ENVSEG dw 0 ; +8 |
SIG1 dw 0x1983 |
SIG2 dw 0x1985 |
SIG3 dw 0x2017 |
SIG4 dw 0x2019 |
; input buffer used for the "previous command" history |
BUF000 db 128, 0 ; +0Ah |
BUF064 db "0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF" |
BUF128 db "0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF" |
; service routine: used by the transient part of svarcom, returns: |
; AX = offset of input buffer history block |
; BX = offset where environment's segment is stored (patched at install time) |
inputroutine: |
mov ax, BUF000 |
mov bx, ENVSEG |
retf |
skipsig: |
skipsig: ; +8Ch |
; set up CS=DS=SS and point SP to my private stack buffer |
mov ax, cs |
mov ds, ax |
38,8 → 38,7 |
mov sp, STACKPTR |
; prepare the exec param block |
mov ax, [ENVSEG] |
mov [EXEC_PARAM_REC], ax |
;mov [EXEC_PARAM_REC], word 0 |
mov ax, COMSPEC |
mov [EXEC_PARAM_REC+2], ax |
mov [EXEC_PARAM_REC+4], ds |
84,7 → 83,15 |
COMSPEC db "C:\SVN\SVARDOS\SVARCOM\COMMAND.COM" |
COMSPCZ db 0 |
; input buffer used for the "previous command" history |
BUF000 db 128, 0 |
BUF064 db "0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF" |
BUF128 db "0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF" |
; FreeDOS int 21h functions that I use require at least 32 bytes of stack, |
; here I allocate 64 bytes to be sure |
STACKBUF db "0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF" |
STACKPTR db "xx" |
; environment segment - this is updated by SvarCOM at init time |
ENVSEG dw 0 |
/svarcom/rmod.h |
---|
1,25 → 1,25 |
const char rmod[] = { |
131, 25,133, 25, 23, 32, 25, 32, 0, 0,128, 0, 48, 49, 50, 51, |
52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, |
52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, |
52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, |
52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, |
52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, |
52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, |
52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, |
52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70,140,200,142,216, |
142,192,142,208,188,106, 1,161, 8, 0,163,208, 0,184, 7, 1, |
163,210, 0,140, 30,212, 0,184, 0, 75,186, 7, 1,187,208, 0, |
205, 33,115,216, 4, 48,162,226, 0,180, 9,186,222, 0,198, 6, |
41, 1, 36,205, 33,198, 6, 41, 1, 0,180, 8,205, 33,235,188, |
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 69, 82, |
82, 32,120, 44, 32, 70, 65, 73, 76, 69, 68, 32, 84, 79, 32, 76, |
79, 65, 68, 32, 67, 79, 77, 77, 65, 78, 68, 46, 67, 79, 77, 32, |
70, 82, 79, 77, 58, 13, 10, 67, 58, 92, 83, 86, 78, 92, 83, 86, |
65, 82, 68, 79, 83, 92, 83, 86, 65, 82, 67, 79, 77, 92, 67, 79, |
77, 77, 65, 78, 68, 46, 67, 79, 77, 0, 48, 49, 50, 51, 52, 53, |
54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, 53, |
54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, 53, |
54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, 53, |
54, 55, 56, 57, 65, 66, 67, 68, 69, 70,120,120}; |
#define rmod_len 364 |
235, 15,131, 25,133, 25, 23, 32, 25, 32,184,169, 0,187,109, 1, |
203,140,200,142,216,142,192,142,208,188,107, 1,184,134, 0,163, |
81, 0,140, 30, 83, 0,184, 0, 75,186,134, 0,187, 79, 0,205, |
33,115,222, 4, 48,162, 97, 0,180, 9,186, 93, 0,198, 6,168, |
0, 36,205, 33,198, 6,168, 0, 0,180, 8,205, 33,235,194, 0, |
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 69, 82, 82, |
32,120, 44, 32, 70, 65, 73, 76, 69, 68, 32, 84, 79, 32, 76, 79, |
65, 68, 32, 67, 79, 77, 77, 65, 78, 68, 46, 67, 79, 77, 32, 70, |
82, 79, 77, 58, 13, 10, 67, 58, 92, 83, 86, 78, 92, 83, 86, 65, |
82, 68, 79, 83, 92, 83, 86, 65, 82, 67, 79, 77, 92, 67, 79, 77, |
77, 65, 78, 68, 46, 67, 79, 77, 0,128, 0, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 48, 49, 50, 51, 52, |
53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70,120,120, 0, 0}; |
#define rmod_len 367 |