| 118,7 → 118,7 |
|---|
| *owner = rmodseg; |
| _fmemcpy(mcb + 8, "SVARCOM", 8); |
| |
| /* mark env memory as "self owned" */ |
| /* mark env memory as "owned by rmod" */ |
| mcb = MK_FP(envseg - 1, 0); |
| owner = (void far *)(mcb + 1); |
| *owner = rmodseg; |
| 149,15 → 149,32 |
|---|
| pop ax |
| } |
| |
| /* set the int22 handler in my PSP to rmod so DOS jumps to rmod after I terminate */ |
| /* set the int22 handler in my PSP to rmod so DOS jumps to rmod after I |
| * terminate and save the original handler in rmod's memory */ |
| _asm { |
| push ax |
| push bx |
| push si |
| push di |
| push es |
| |
| /* save my original parent in rmod's memory */ |
| mov es, [rmodseg] |
| mov si, 0x0a |
| mov di, RMOD_OFFSET_ORIGPARENT |
| cld |
| movsw /* mov ES:[DI], DS:[SI] and SI += 2 and DI += 2 */ |
| movsw |
| |
| mov bx, 0x0a /* int22 handler is at 0x0A of the PSP */ |
| mov ax, RMOD_OFFSET_ROUTINE |
| mov [bx], ax /* int handler offset */ |
| mov ax, rmodseg |
| mov [bx+2], ax /* int handler segment */ |
| |
| pop es |
| pop di |
| pop si |
| pop bx |
| pop ax |
| } |
| 166,29 → 183,18 |
|---|
| } |
| |
| |
| /* scan memory for rmod, returns its segment if found, 0xffff otherwise */ |
| /* look up my parent: if it's rmod then return its segment, |
| * otherwise return 0xffff */ |
| unsigned short rmod_find(void) { |
| unsigned short i; |
| unsigned short far *ptrword; |
| unsigned char far *ptrbyte; |
| |
| /* iterate over all paragraphs, looking for my signature */ |
| for (i = 1; i != 65535; i++) { |
| ptrword = MK_FP(i, 0); |
| if (ptrword[0] != 0x1983) continue; |
| if (ptrword[1] != 0x1985) continue; |
| if (ptrword[2] != 0x2017) continue; |
| if (ptrword[3] != 0x2019) continue; |
| /* extra check: make sure the paragraph before is an MCB block and that it |
| * belongs to itself. otherwise I could find the rmod code embedded inside |
| * the command.com binary... */ |
| ptrbyte = MK_FP(i - 1, 0); |
| if ((*ptrbyte != 'M') && (*ptrbyte != 'Z')) continue; /* not an MCB */ |
| ptrword = MK_FP(i - 1, 1); |
| if (*ptrword != i) continue; /* not belonging to self */ |
| return(i); |
| } |
| return(0xffff); |
| unsigned short *parent = (void *)0x0C; /* parent's seg in PSP[Ch] ("prev. int22 handler") */ |
| unsigned short far *ptr; |
| const unsigned short sig[] = {0x1983, 0x1985, 0x2017, 0x2019}; |
| unsigned char i; |
| /* is it rmod? */ |
| ptr = MK_FP(*parent, 0); |
| for (i = 0; i < 4; i++) if (ptr[i] != sig[i]) return(0xffff); |
| /* match successfull (rmod is my parent) */ |
| return(*parent); |
| } |
| |
| |