WebSVN – SvarDOS – Diff – /svarcom/trunk/rmodinit.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.
 */
 
#include <i86.h>
#include <string.h>
 
#include "env.h"
#include "helpers.h"
 
#include "rmodinit.h"
 
 
/* returns far pointer to rmod's settings block on success */
struct rmod_props far *rmod_install(unsigned short envsize, unsigned char *rmodcore, unsigned short rmodcore_len) {
  char far *myptr, far *mcb;
  unsigned short far *owner;
  const unsigned short sizeof_rmodandprops_paras = (0x100 + rmodcore_len + sizeof(struct rmod_props) + 15) / 16;
  unsigned short rmodseg = 0xffff;
  unsigned short envseg, origenvseg;
  struct rmod_props far *res;
 
  /* read my current env segment from PSP and save it */
  envseg = *((unsigned short *)0x2c);
  origenvseg = envseg;
 
  /* printf("original (PSP) env buffer at %04X\r\n", envseg); */
 
  /* if envseg is zero, then enforce our own one (MSDOS 5 does not provide a default env) */
  if ((envseg == 0) && (envsize == 0)) envsize = 256;
 
  /* 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
    xor ah, ah
    push ax         /* save link state on stack */
    mov ax, 0x5803  /* SET UMB LINK STATE */
    mov bx, 1
    int 0x21
    /* get current allocation strategy and save it in DX */
    mov ax, 0x5800
    int 0x21
    push ax
    pop dx
    /* set strategy to 'last fit, try high then low memory' */
    mov ax, 0x5801
    mov bx, 0x0082
    int 0x21
    /* ask for a memory block and save the given segment to rmodseg */
    mov ah, 0x48
    mov bx, sizeof_rmodandprops_paras
    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
 
    ALLOC_FAIL:
    /* restore initial allocation strategy */
    mov ax, 0x5801
    mov bx, dx
    int 0x21
    /* restore initial UMB memory link state */
    mov ax, 0x5803
    pop bx       /* pop initial UMB link state from stack */
    int 0x21
  }
 
  if (rmodseg == 0xffff) {
    outputnl("malloc error");
    return(NULL);
  }
 
  /* copy rmod to its destination, prefixed with a copy of my own PSP */
  myptr = MK_FP(rmodseg, 0);
  {
    unsigned short i;
    char *mypsp = (void *)0;
    for (i = 0; i < 0x100; i++) myptr[i] = mypsp[i];
  }
  myptr = MK_FP(rmodseg, 0x100);
  _fmemcpy(myptr, rmodcore, rmodcore_len);
 
  /* mark rmod memory as "self owned" */
  mcb = MK_FP(rmodseg - 1, 0);
  owner = (void far *)(mcb + 1);
  *owner = rmodseg;
  _fmemcpy(mcb + 8, "SVARCOM", 8);
 
  /* mark env memory as "owned by rmod" */
  mcb = MK_FP(envseg - 1, 0);
  owner = (void far *)(mcb + 1);
  *owner = rmodseg;
  _fmemcpy(mcb + 8, "SVARENV", 8);
 
  /* if env block is newly allocated, fill it with a few NULLs */
  if (envsize != 0) {
    owner = MK_FP(envseg, 0);
    owner[0] = 0;
    owner[1] = 0;
  }
 
  /* set CTRL+BREAK handler to rmod */
  _asm {
    push ax
    push dx
    push ds
    mov ax, 0x2523
    mov ds, rmodseg
    mov dx, RMOD_OFFSET_BRKHANDLER
    int 0x21
    pop ds
    pop dx
    pop ax
  }
 
  /* prepare result (rmod props) */
  res = MK_FP(rmodseg, 0x100 + rmodcore_len);
  _fmemset(res, 0, sizeof(*res));  /* zero out */
  res->rmodseg = rmodseg;          /* rmod segment */
  res->inputbuf[0] = 128;          /* input buffer for INT 0x21, AH=0Ah*/
  res->origenvseg = origenvseg;    /* original environment segment */
 
  /* write env segment to rmod's PSP */
  owner = MK_FP(rmodseg, RMOD_OFFSET_ENVSEG);
  *owner = envseg;
 
  /* write boot drive to rmod bootdrive field */
  _asm {
    push ax
    push bx
    push dx
    push ds
    mov ax, 0x3305 /* DOS 4.0+ - GET BOOT DRIVE */
    int 0x21 /* boot drive is in DL now (1=A:, 2=B:, etc) */
    add dl, 'A'-1 /* convert to a proper ASCII letter */
    /* set DS to rmodseg */
    mov ax, rmodseg
    mov ds, ax
    /* write boot drive to rmod bootdrive field */
    mov bx, RMOD_OFFSET_BOOTDRIVE
    mov [bx], dl
    pop ds
    pop dx
    pop bx
    pop ax
  }
 
  /* save my original parent in rmod's memory */
  res->origparent = *((unsigned long *)0x0a); /* original parent seg:off is at 0x0a of my PSP */
 
  /* 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 */
  {
    unsigned short *ptr = (void *)0x0a; /* int22 handler is at 0x0A of the PSP */
    ptr[0] = RMOD_OFFSET_ROUTINE;
    ptr[1] = rmodseg;
  }
 
  return(res);
}
 
 
/* look up my parent: if it's rmod then return a ptr to its props struct,
 * otherwise return NULL */
struct rmod_props far *rmod_find(unsigned short rmodcore_len) {
  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 *cmdtail = (void *)0x80;
  unsigned char i;
  /* is it rmod? */
  ptr = MK_FP(*parent, 0x100);
  for (i = 0; i < 4; i++) if (ptr[i] != sig[i]) return(NULL);
  /* match successfull (rmod is my parent) - but is it really a respawn?
   * command-line tail should contain a single character '\r' */
  if ((cmdtail[0] != 1) || (cmdtail[1] != '\n')) return(NULL);
  cmdtail[0] = 0;
  cmdtail[1] = '\r';
  /* */
  return(MK_FP(*parent, 0x100 + rmodcore_len));
}
 
 
/* update rmod's pointer to comspec */
void rmod_updatecomspecptr(unsigned short rmod_seg, unsigned short env_seg) {
  unsigned short far *comspecptr = MK_FP(rmod_seg, RMOD_OFFSET_COMSPECPTR);
  char far *comspecfp = env_lookup_val(env_seg, "COMSPEC");
  if (comspecfp != NULL) {
    *comspecptr = FP_OFF(comspecfp);
  } else {
    *comspecptr = 0;
  }
}
 

Rev 479	Rev 537
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	`#include <i86.h>`	25	`#include <i86.h>`
26	`#include <string.h>`	26	`#include <string.h>`
27		27
28	`#include "env.h"`	28	`#include "env.h"`
29	`#include "helpers.h"`	29	`#include "helpers.h"`
30		30
31	`#include "rmodinit.h"`	31	`#include "rmodinit.h"`
32		32
33		33
34	`/* returns far pointer to rmod's settings block on success */`	34	`/* returns far pointer to rmod's settings block on success */`
35	`struct rmod_props far rmod_install(unsigned short envsize, unsigned char rmodcore, unsigned short rmodcore_len) {`	35	`struct rmod_props far rmod_install(unsigned short envsize, unsigned char rmodcore, unsigned short rmodcore_len) {`
36	`char far myptr, far mcb;`	36	`char far myptr, far mcb;`
37	`unsigned short far *owner;`	37	`unsigned short far *owner;`
38	`const unsigned short sizeof_rmodandprops_paras = (0x100 + rmodcore_len + sizeof(struct rmod_props) + 15) / 16;`	38	`const unsigned short sizeof_rmodandprops_paras = (0x100 + rmodcore_len + sizeof(struct rmod_props) + 15) / 16;`
39	`unsigned short rmodseg = 0xffff;`	39	`unsigned short rmodseg = 0xffff;`
40	`unsigned short envseg, origenvseg;`	40	`unsigned short envseg, origenvseg;`
41	`struct rmod_props far *res;`	41	`struct rmod_props far *res;`
42		42
43	`/* read my current env segment from PSP and save it */`	43	`/* read my current env segment from PSP and save it */`
44	`envseg = ((unsigned short )0x2c);`	44	`envseg = ((unsigned short )0x2c);`
45	`origenvseg = envseg;`	45	`origenvseg = envseg;`
46		46
47	`/* printf("original (PSP) env buffer at %04X\r\n", envseg); */`	47	`/* printf("original (PSP) env buffer at %04X\r\n", envseg); */`
48		48
49	`/* if envseg is zero, then enforce our own one (MSDOS 5 does not provide a default env) */`	49	`/* if envseg is zero, then enforce our own one (MSDOS 5 does not provide a default env) */`
50	`if ((envseg == 0) && (envsize == 0)) envsize = 256;`	50	`if ((envseg == 0) && (envsize == 0)) envsize = 256;`
51		51
52	`/* if custom envsize requested, convert it to number of paragraphs */`	52	`/* if custom envsize requested, convert it to number of paragraphs */`
53	`if (envsize != 0) {`	53	`if (envsize != 0) {`
54	`envsize += 15;`	54	`envsize += 15;`
55	`envsize /= 16;`	55	`envsize /= 16;`
56	`}`	56	`}`
57		57
58	`_asm {`	58	`_asm {`
59	`/* link in the UMB memory chain for enabling high-memory allocation (and save initial status on stack) */`	59	`/* link in the UMB memory chain for enabling high-memory allocation (and save initial status on stack) */`
60	`mov ax, 0x5802 /* GET UMB LINK STATE */`	60	`mov ax, 0x5802 /* GET UMB LINK STATE */`
61	`int 0x21`	61	`int 0x21`
62	`xor ah, ah`	62	`xor ah, ah`
63	`push ax /* save link state on stack */`	63	`push ax /* save link state on stack */`
64	`mov ax, 0x5803 /* SET UMB LINK STATE */`	64	`mov ax, 0x5803 /* SET UMB LINK STATE */`
65	`mov bx, 1`	65	`mov bx, 1`
66	`int 0x21`	66	`int 0x21`
67	`/* get current allocation strategy and save it in DX */`	67	`/* get current allocation strategy and save it in DX */`
68	`mov ax, 0x5800`	68	`mov ax, 0x5800`
69	`int 0x21`	69	`int 0x21`
70	`push ax`	70	`push ax`
71	`pop dx`	71	`pop dx`
72	`/* set strategy to 'last fit, try high then low memory' */`	72	`/* set strategy to 'last fit, try high then low memory' */`
73	`mov ax, 0x5801`	73	`mov ax, 0x5801`
74	`mov bx, 0x0082`	74	`mov bx, 0x0082`
75	`int 0x21`	75	`int 0x21`
76	`/* ask for a memory block and save the given segment to rmodseg */`	76	`/* ask for a memory block and save the given segment to rmodseg */`
77	`mov ah, 0x48`	77	`mov ah, 0x48`
78	`mov bx, sizeof_rmodandprops_paras`	78	`mov bx, sizeof_rmodandprops_paras`
79	`int 0x21`	79	`int 0x21`
80	`jc ALLOC_FAIL`	80	`jc ALLOC_FAIL`
81	`mov rmodseg, ax`	81	`mov rmodseg, ax`
82	`/* ask for a memory block for the environment and save it to envseg (only if custom size requested) */`	82	`/* ask for a memory block for the environment and save it to envseg (only if custom size requested) */`
83	`mov bx, envsize`	83	`mov bx, envsize`
84	`test bx, bx`	84	`test bx, bx`
85	`jz ALLOC_FAIL`	85	`jz ALLOC_FAIL`
86	`mov ah, 0x48`	86	`mov ah, 0x48`
87	`int 0x21`	87	`int 0x21`
88	`jc ALLOC_FAIL`	88	`jc ALLOC_FAIL`
89	`mov envseg, ax`	89	`mov envseg, ax`
90		90
91	`ALLOC_FAIL:`	91	`ALLOC_FAIL:`
92	`/* restore initial allocation strategy */`	92	`/* restore initial allocation strategy */`
93	`mov ax, 0x5801`	93	`mov ax, 0x5801`
94	`mov bx, dx`	94	`mov bx, dx`
95	`int 0x21`	95	`int 0x21`
96	`/* restore initial UMB memory link state */`	96	`/* restore initial UMB memory link state */`
97	`mov ax, 0x5803`	97	`mov ax, 0x5803`
98	`pop bx /* pop initial UMB link state from stack */`	98	`pop bx /* pop initial UMB link state from stack */`
99	`int 0x21`	99	`int 0x21`
100	`}`	100	`}`
101		101
102	`if (rmodseg == 0xffff) {`	102	`if (rmodseg == 0xffff) {`
103	`outputnl("malloc error");`	103	`outputnl("malloc error");`
104	`return(NULL);`	104	`return(NULL);`
105	`}`	105	`}`
106		106
107	`/* copy rmod to its destination, prefixed with a copy of my own PSP */`	107	`/* copy rmod to its destination, prefixed with a copy of my own PSP */`
108	`myptr = MK_FP(rmodseg, 0);`	108	`myptr = MK_FP(rmodseg, 0);`
109	`{`	109	`{`
110	`unsigned short i;`	110	`unsigned short i;`
111	`char mypsp = (void )0;`	111	`char mypsp = (void )0;`
112	`for (i = 0; i < 0x100; i++) myptr[i] = mypsp[i];`	112	`for (i = 0; i < 0x100; i++) myptr[i] = mypsp[i];`
113	`}`	113	`}`
114	`myptr = MK_FP(rmodseg, 0x100);`	114	`myptr = MK_FP(rmodseg, 0x100);`
115	`_fmemcpy(myptr, rmodcore, rmodcore_len);`	115	`_fmemcpy(myptr, rmodcore, rmodcore_len);`
116		116
117	`/* mark rmod memory as "self owned" */`	117	`/* mark rmod memory as "self owned" */`
118	`mcb = MK_FP(rmodseg - 1, 0);`	118	`mcb = MK_FP(rmodseg - 1, 0);`
119	`owner = (void far *)(mcb + 1);`	119	`owner = (void far *)(mcb + 1);`
120	`*owner = rmodseg;`	120	`*owner = rmodseg;`
121	`_fmemcpy(mcb + 8, "SVARCOM", 8);`	121	`_fmemcpy(mcb + 8, "SVARCOM", 8);`
122		122
123	`/* mark env memory as "owned by rmod" */`	123	`/* mark env memory as "owned by rmod" */`
124	`mcb = MK_FP(envseg - 1, 0);`	124	`mcb = MK_FP(envseg - 1, 0);`
125	`owner = (void far *)(mcb + 1);`	125	`owner = (void far *)(mcb + 1);`
126	`*owner = rmodseg;`	126	`*owner = rmodseg;`
127	`_fmemcpy(mcb + 8, "SVARENV", 8);`	127	`_fmemcpy(mcb + 8, "SVARENV", 8);`
128		128
129	`/* if env block is newly allocated, fill it with a few NULLs */`	129	`/* if env block is newly allocated, fill it with a few NULLs */`
130	`if (envsize != 0) {`	130	`if (envsize != 0) {`
131	`owner = MK_FP(envseg, 0);`	131	`owner = MK_FP(envseg, 0);`
132	`owner[0] = 0;`	132	`owner[0] = 0;`
133	`owner[1] = 0;`	133	`owner[1] = 0;`
134	`}`	134	`}`
135		135
-		136	`/* set CTRL+BREAK handler to rmod */`
-		137	`_asm {`
-		138	`push ax`
-		139	`push dx`
-		140	`push ds`
-		141	`mov ax, 0x2523`
-		142	`mov ds, rmodseg`
-		143	`mov dx, RMOD_OFFSET_BRKHANDLER`
-		144	`int 0x21`
-		145	`pop ds`
-		146	`pop dx`
-		147	`pop ax`
-		148	`}`
-		149
136	`/* prepare result (rmod props) */`	150	`/* prepare result (rmod props) */`
137	`res = MK_FP(rmodseg, 0x100 + rmodcore_len);`	151	`res = MK_FP(rmodseg, 0x100 + rmodcore_len);`
138	`_fmemset(res, 0, sizeof(res)); / zero out */`	152	`_fmemset(res, 0, sizeof(res)); / zero out */`
139	`res->rmodseg = rmodseg; /* rmod segment */`	153	`res->rmodseg = rmodseg; /* rmod segment */`
140	`res->inputbuf[0] = 128; /* input buffer for INT 0x21, AH=0Ah*/`	154	`res->inputbuf[0] = 128; /* input buffer for INT 0x21, AH=0Ah*/`
141	`res->origenvseg = origenvseg; /* original environment segment */`	155	`res->origenvseg = origenvseg; /* original environment segment */`
142		156
143	`/* write env segment to rmod's PSP */`	157	`/* write env segment to rmod's PSP */`
144	`owner = MK_FP(rmodseg, RMOD_OFFSET_ENVSEG);`	158	`owner = MK_FP(rmodseg, RMOD_OFFSET_ENVSEG);`
145	`*owner = envseg;`	159	`*owner = envseg;`
146		160
147	`/* write boot drive to rmod bootdrive field */`	161	`/* write boot drive to rmod bootdrive field */`
148	`_asm {`	162	`_asm {`
149	`push ax`	163	`push ax`
150	`push bx`	164	`push bx`
151	`push dx`	165	`push dx`
152	`push ds`	166	`push ds`
153	`mov ax, 0x3305 /* DOS 4.0+ - GET BOOT DRIVE */`	167	`mov ax, 0x3305 /* DOS 4.0+ - GET BOOT DRIVE */`
154	`int 0x21 /* boot drive is in DL now (1=A:, 2=B:, etc) */`	168	`int 0x21 /* boot drive is in DL now (1=A:, 2=B:, etc) */`
155	`add dl, 'A'-1 /* convert to a proper ASCII letter */`	169	`add dl, 'A'-1 /* convert to a proper ASCII letter */`
156	`/* set DS to rmodseg */`	170	`/* set DS to rmodseg */`
157	`mov ax, rmodseg`	171	`mov ax, rmodseg`
158	`mov ds, ax`	172	`mov ds, ax`
159	`/* write boot drive to rmod bootdrive field */`	173	`/* write boot drive to rmod bootdrive field */`
160	`mov bx, RMOD_OFFSET_BOOTDRIVE`	174	`mov bx, RMOD_OFFSET_BOOTDRIVE`
161	`mov [bx], dl`	175	`mov [bx], dl`
162	`pop ds`	176	`pop ds`
163	`pop dx`	177	`pop dx`
164	`pop bx`	178	`pop bx`
165	`pop ax`	179	`pop ax`
166	`}`	180	`}`
167		181
168	`/* save my original parent in rmod's memory */`	182	`/* save my original parent in rmod's memory */`
169	`res->origparent = ((unsigned long )0x0a); /* original parent seg:off is at 0x0a of my PSP */`	183	`res->origparent = ((unsigned long )0x0a); /* original parent seg:off is at 0x0a of my PSP */`
170		184
171	`/* set the int22 handler in my PSP to rmod so DOS jumps to rmod after I`	185	`/* set the int22 handler in my PSP to rmod so DOS jumps to rmod after I`
172	`* terminate and save the original handler in rmod's memory */`	186	`* terminate and save the original handler in rmod's memory */`
173	`{`	187	`{`
174	`unsigned short ptr = (void )0x0a; /* int22 handler is at 0x0A of the PSP */`	188	`unsigned short ptr = (void )0x0a; /* int22 handler is at 0x0A of the PSP */`
175	`ptr[0] = RMOD_OFFSET_ROUTINE;`	189	`ptr[0] = RMOD_OFFSET_ROUTINE;`
176	`ptr[1] = rmodseg;`	190	`ptr[1] = rmodseg;`
177	`}`	191	`}`
178		192
179	`return(res);`	193	`return(res);`
180	`}`	194	`}`
181		195
182		196
183	`/* look up my parent: if it's rmod then return a ptr to its props struct,`	197	`/* look up my parent: if it's rmod then return a ptr to its props struct,`
184	`* otherwise return NULL */`	198	`* otherwise return NULL */`
185	`struct rmod_props far *rmod_find(unsigned short rmodcore_len) {`	199	`struct rmod_props far *rmod_find(unsigned short rmodcore_len) {`
186	`unsigned short parent = (void )0x0C; /* parent's seg in PSP[Ch] ("prev. int22 handler") */`	200	`unsigned short parent = (void )0x0C; /* parent's seg in PSP[Ch] ("prev. int22 handler") */`
187	`unsigned short far *ptr;`	201	`unsigned short far *ptr;`
188	`const unsigned short sig[] = {0x1983, 0x1985, 0x2017, 0x2019};`	202	`const unsigned short sig[] = {0x1983, 0x1985, 0x2017, 0x2019};`
189	`unsigned char cmdtail = (void )0x80;`	203	`unsigned char cmdtail = (void )0x80;`
190	`unsigned char i;`	204	`unsigned char i;`
191	`/* is it rmod? */`	205	`/* is it rmod? */`
192	`ptr = MK_FP(*parent, 0x100);`	206	`ptr = MK_FP(*parent, 0x100);`
193	`for (i = 0; i < 4; i++) if (ptr[i] != sig[i]) return(NULL);`	207	`for (i = 0; i < 4; i++) if (ptr[i] != sig[i]) return(NULL);`
194	`/* match successfull (rmod is my parent) - but is it really a respawn?`	208	`/* match successfull (rmod is my parent) - but is it really a respawn?`
195	`* command-line tail should contain a single character '\r' */`	209	`* command-line tail should contain a single character '\r' */`
196	`if ((cmdtail[0] != 1) \|\| (cmdtail[1] != '\n')) return(NULL);`	210	`if ((cmdtail[0] != 1) \|\| (cmdtail[1] != '\n')) return(NULL);`
197	`cmdtail[0] = 0;`	211	`cmdtail[0] = 0;`
198	`cmdtail[1] = '\r';`	212	`cmdtail[1] = '\r';`
199	`/* */`	213	`/* */`
200	`return(MK_FP(*parent, 0x100 + rmodcore_len));`	214	`return(MK_FP(*parent, 0x100 + rmodcore_len));`
201	`}`	215	`}`
202		216
203		217
204	`/* update rmod's pointer to comspec */`	218	`/* update rmod's pointer to comspec */`
205	`void rmod_updatecomspecptr(unsigned short rmod_seg, unsigned short env_seg) {`	219	`void rmod_updatecomspecptr(unsigned short rmod_seg, unsigned short env_seg) {`
206	`unsigned short far *comspecptr = MK_FP(rmod_seg, RMOD_OFFSET_COMSPECPTR);`	220	`unsigned short far *comspecptr = MK_FP(rmod_seg, RMOD_OFFSET_COMSPECPTR);`
207	`char far *comspecfp = env_lookup_val(env_seg, "COMSPEC");`	221	`char far *comspecfp = env_lookup_val(env_seg, "COMSPEC");`
208	`if (comspecfp != NULL) {`	222	`if (comspecfp != NULL) {`
209	`*comspecptr = FP_OFF(comspecfp);`	223	`*comspecptr = FP_OFF(comspecfp);`
210	`} else {`	224	`} else {`
211	`*comspecptr = 0;`	225	`*comspecptr = 0;`
212	`}`	226	`}`
213	`}`	227	`}`
214		228

Subversion Repositories SvarDOS

(root)/svarcom/trunk/rmodinit.c – Rev 479 → 537