WebSVN – SvarDOS – Diff – /svarcom/trunk/redir.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 "doserr.h"
#include "helpers.h"
 
#include "redir.h"
 
static unsigned short oldstdout = 0xffff;
 
/* parse commandline and performs necessary redirections. cmdline is
 * modified so all redirections are cut out.
 * returns 0 on success, non-zero otherwise */
int redir_parsecmd(char far *cmdline, char *BUFFER) {
  unsigned short i;
  unsigned short rediroffset_stdin = 0;
  unsigned short rediroffset_stdout = 0;
  unsigned short pipesoffsets[16];
  unsigned short pipescount = 0;
 
  /* NOTE:
   *
   * 1. while it is possible to type a command with multiple
   *    redirections, MSDOS executes only the last redirection.
   *
   * 2. the order in which >, < and | are provided on the command line does
   *    not seem to matter for MSDOS. piped commands are executed first (in
   *    the order they appear) and the result of the last one is redirected to
   *    whenever the last > points at.
   */
 
  /* preset oldstdout to 0xffff in case no redirection is required */
  oldstdout = 0xffff;
 
  for (i = 0;; i++) {
    if (cmdline[i] == '>') {
      cmdline[i] = 0;
      rediroffset_stdout = i + 1;
    } else if (cmdline[i] == '<') {
      cmdline[i] = 0;
      rediroffset_stdin = i + 1;
    } else if (cmdline[i] == '|') {
      cmdline[i] = 0;
      pipesoffsets[pipescount++] = i + 1;
    } else if (cmdline[i] == 0) {
      break;
    }
  }
 
  if (rediroffset_stdin != 0) {
    outputnl("ERROR: stdin redirection is not supported yet");
    return(-1);
  }
 
  if (pipescount != 0) {
    outputnl("ERROR: pipe redirections are not supported yet");
    return(-1);
  }
 
  if (rediroffset_stdout != 0) {
    unsigned short openflag = 0x12;  /* used during the int 21h,ah=6c call */
    unsigned short errcode = 0;
    unsigned short handle = 0;
    char far *ptr;
    /* append? */
    if (cmdline[rediroffset_stdout] == '>') {
      openflag = 0x11;
      rediroffset_stdout++;
    }
 
    /* copy dst file to BUFFER */
    ptr = cmdline + rediroffset_stdout;
    while (*ptr == ' ') ptr++; /* skip leading white spaces */
    for (i = 0;; i++) {
      BUFFER[i] = ptr[i];
      if ((BUFFER[i] == ' ') || (BUFFER[i] == 0)) break;
    }
    BUFFER[i] = 0;
 
    /* */
    _asm {
      push ax
      push bx
      push cx
      push dx
      push si
      mov ax, 0x6c00     /* Extended Open/Create */
      mov bx, 1          /* access mode (0=read, 1=write, 2=r+w */
      xor cx, cx         /* attributes when(if) creating the file (0=normal) */
      mov dx, [openflag] /* action if file exists (0x11=open, 0x12=truncate)*/
      mov si, BUFFER     /* ASCIIZ filename */
      int 0x21           /* AX=handle on success (CF clear), otherwise dos err */
      mov [handle], ax   /* save the file handler */
      jnc DUPSTDOUT
      mov [errcode], ax
      jmp DONE
      DUPSTDOUT:
      /* save (duplicate) current stdout so I can revert it later */
      mov ah, 0x45       /* duplicate file handle */
      mov bx, 1          /* handle to dup (1=stdout) */
      int 0x21           /* ax = new file handle */
      mov [oldstdout], ax
      /* redirect the stdout handle */
      mov bx, [handle]   /* dst handle */
      mov cx, 1          /* src handle (1=stdout) */
      mov ah, 0x46       /* redirect a handle */
      int 0x21
      /* close the original file handle (no longer needed) */
      mov ah, 0x3e       /* close a file handle (handle in BX) */
      int 0x21
      DONE:
      pop si
      pop dx
      pop cx
      pop bx
      pop ax
    }
    if (errcode != 0) {
      outputnl(doserr(errcode));
      return(-1);
    }
  }
 
  return(0);
}
 
 
/* restores previous stdout/stdin handlers if they have been redirected */
void redir_revert(void) {
  _asm {
    /* if oldstdout is 0xffff then not redirected */
    cmp word ptr [oldstdout], 0xffff
    je DONE
    /* redirect the stdout handle */
    mov bx, [oldstdout] /* dst handle */
    mov cx, 1           /* src handle (1=stdout) */
    mov ah, 0x46        /* redirect a handle */
    int 0x21
    mov [oldstdout], 0xffff
    DONE:
  }
}
 

Rev 402	Rev 421
-		1	`/* This file is part of the SvarCOM project and is published under the terms`
-		2	`* of the MIT license.`
-		3	`*`
-		4	`* Copyright (C) 2021 Mateusz Viste`
-		5	`*`
-		6	`* Permission is hereby granted, free of charge, to any person obtaining a`
-		7	`* copy of this software and associated documentation files (the "Software"),`
-		8	`* to deal in the Software without restriction, including without limitation`
-		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`
-		11	`* Software is furnished to do so, subject to the following conditions:`
-		12	`*`
-		13	`* The above copyright notice and this permission notice shall be included in`
-		14	`* all copies or substantial portions of the Software.`
-		15	`*`
-		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,`
-		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`
-		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`
-		22	`* DEALINGS IN THE SOFTWARE.`
-		23	`*/`
1		24
2	`#include "doserr.h"`	25	`#include "doserr.h"`
3	`#include "helpers.h"`	26	`#include "helpers.h"`
4		27
5	`#include "redir.h"`	28	`#include "redir.h"`
6		29
7	`static unsigned short oldstdout = 0xffff;`	30	`static unsigned short oldstdout = 0xffff;`
8		31
9	`/* parse commandline and performs necessary redirections. cmdline is`	32	`/* parse commandline and performs necessary redirections. cmdline is`
10	`* modified so all redirections are cut out.`	33	`* modified so all redirections are cut out.`
11	`* returns 0 on success, non-zero otherwise */`	34	`* returns 0 on success, non-zero otherwise */`
12	`int redir_parsecmd(char far cmdline, char BUFFER) {`	35	`int redir_parsecmd(char far cmdline, char BUFFER) {`
13	`unsigned short i;`	36	`unsigned short i;`
14	`unsigned short rediroffset_stdin = 0;`	37	`unsigned short rediroffset_stdin = 0;`
15	`unsigned short rediroffset_stdout = 0;`	38	`unsigned short rediroffset_stdout = 0;`
16	`unsigned short pipesoffsets[16];`	39	`unsigned short pipesoffsets[16];`
17	`unsigned short pipescount = 0;`	40	`unsigned short pipescount = 0;`
18		41
19	`/* NOTE:`	42	`/* NOTE:`
20	`*`	43	`*`
21	`* 1. while it is possible to type a command with multiple`	44	`* 1. while it is possible to type a command with multiple`
22	`* redirections, MSDOS executes only the last redirection.`	45	`* redirections, MSDOS executes only the last redirection.`
23	`*`	46	`*`
24	`* 2. the order in which >, < and \| are provided on the command line does`	47	`* 2. the order in which >, < and \| are provided on the command line does`
25	`* not seem to matter for MSDOS. piped commands are executed first (in`	48	`* not seem to matter for MSDOS. piped commands are executed first (in`
26	`* the order they appear) and the result of the last one is redirected to`	49	`* the order they appear) and the result of the last one is redirected to`
27	`* whenever the last > points at.`	50	`* whenever the last > points at.`
28	`*/`	51	`*/`
29		52
30	`/* preset oldstdout to 0xffff in case no redirection is required */`	53	`/* preset oldstdout to 0xffff in case no redirection is required */`
31	`oldstdout = 0xffff;`	54	`oldstdout = 0xffff;`
32		55
33	`for (i = 0;; i++) {`	56	`for (i = 0;; i++) {`
34	`if (cmdline[i] == '>') {`	57	`if (cmdline[i] == '>') {`
35	`cmdline[i] = 0;`	58	`cmdline[i] = 0;`
36	`rediroffset_stdout = i + 1;`	59	`rediroffset_stdout = i + 1;`
37	`} else if (cmdline[i] == '<') {`	60	`} else if (cmdline[i] == '<') {`
38	`cmdline[i] = 0;`	61	`cmdline[i] = 0;`
39	`rediroffset_stdin = i + 1;`	62	`rediroffset_stdin = i + 1;`
40	`} else if (cmdline[i] == '\|') {`	63	`} else if (cmdline[i] == '\|') {`
41	`cmdline[i] = 0;`	64	`cmdline[i] = 0;`
42	`pipesoffsets[pipescount++] = i + 1;`	65	`pipesoffsets[pipescount++] = i + 1;`
43	`} else if (cmdline[i] == 0) {`	66	`} else if (cmdline[i] == 0) {`
44	`break;`	67	`break;`
45	`}`	68	`}`
46	`}`	69	`}`
47		70
48	`if (rediroffset_stdin != 0) {`	71	`if (rediroffset_stdin != 0) {`
49	`outputnl("ERROR: stdin redirection is not supported yet");`	72	`outputnl("ERROR: stdin redirection is not supported yet");`
50	`return(-1);`	73	`return(-1);`
51	`}`	74	`}`
52		75
53	`if (pipescount != 0) {`	76	`if (pipescount != 0) {`
54	`outputnl("ERROR: pipe redirections are not supported yet");`	77	`outputnl("ERROR: pipe redirections are not supported yet");`
55	`return(-1);`	78	`return(-1);`
56	`}`	79	`}`
57		80
58	`if (rediroffset_stdout != 0) {`	81	`if (rediroffset_stdout != 0) {`
59	`unsigned short openflag = 0x12; /* used during the int 21h,ah=6c call */`	82	`unsigned short openflag = 0x12; /* used during the int 21h,ah=6c call */`
60	`unsigned short errcode = 0;`	83	`unsigned short errcode = 0;`
61	`unsigned short handle = 0;`	84	`unsigned short handle = 0;`
62	`char far *ptr;`	85	`char far *ptr;`
63	`/* append? */`	86	`/* append? */`
64	`if (cmdline[rediroffset_stdout] == '>') {`	87	`if (cmdline[rediroffset_stdout] == '>') {`
65	`openflag = 0x11;`	88	`openflag = 0x11;`
66	`rediroffset_stdout++;`	89	`rediroffset_stdout++;`
67	`}`	90	`}`
68		91
69	`/* copy dst file to BUFFER */`	92	`/* copy dst file to BUFFER */`
70	`ptr = cmdline + rediroffset_stdout;`	93	`ptr = cmdline + rediroffset_stdout;`
71	`while (ptr == ' ') ptr++; / skip leading white spaces */`	94	`while (ptr == ' ') ptr++; / skip leading white spaces */`
72	`for (i = 0;; i++) {`	95	`for (i = 0;; i++) {`
73	`BUFFER[i] = ptr[i];`	96	`BUFFER[i] = ptr[i];`
74	`if ((BUFFER[i] == ' ') \|\| (BUFFER[i] == 0)) break;`	97	`if ((BUFFER[i] == ' ') \|\| (BUFFER[i] == 0)) break;`
75	`}`	98	`}`
76	`BUFFER[i] = 0;`	99	`BUFFER[i] = 0;`
77		100
78	`/* */`	101	`/* */`
79	`_asm {`	102	`_asm {`
80	`push ax`	103	`push ax`
81	`push bx`	104	`push bx`
82	`push cx`	105	`push cx`
83	`push dx`	106	`push dx`
84	`push si`	107	`push si`
85	`mov ax, 0x6c00 /* Extended Open/Create */`	108	`mov ax, 0x6c00 /* Extended Open/Create */`
86	`mov bx, 1 /* access mode (0=read, 1=write, 2=r+w */`	109	`mov bx, 1 /* access mode (0=read, 1=write, 2=r+w */`
87	`xor cx, cx /* attributes when(if) creating the file (0=normal) */`	110	`xor cx, cx /* attributes when(if) creating the file (0=normal) */`
88	`mov dx, [openflag] /* action if file exists (0x11=open, 0x12=truncate)*/`	111	`mov dx, [openflag] /* action if file exists (0x11=open, 0x12=truncate)*/`
89	`mov si, BUFFER /* ASCIIZ filename */`	112	`mov si, BUFFER /* ASCIIZ filename */`
90	`int 0x21 /* AX=handle on success (CF clear), otherwise dos err */`	113	`int 0x21 /* AX=handle on success (CF clear), otherwise dos err */`
91	`mov [handle], ax /* save the file handler */`	114	`mov [handle], ax /* save the file handler */`
92	`jnc DUPSTDOUT`	115	`jnc DUPSTDOUT`
93	`mov [errcode], ax`	116	`mov [errcode], ax`
94	`jmp DONE`	117	`jmp DONE`
95	`DUPSTDOUT:`	118	`DUPSTDOUT:`
96	`/* save (duplicate) current stdout so I can revert it later */`	119	`/* save (duplicate) current stdout so I can revert it later */`
97	`mov ah, 0x45 /* duplicate file handle */`	120	`mov ah, 0x45 /* duplicate file handle */`
98	`mov bx, 1 /* handle to dup (1=stdout) */`	121	`mov bx, 1 /* handle to dup (1=stdout) */`
99	`int 0x21 /* ax = new file handle */`	122	`int 0x21 /* ax = new file handle */`
100	`mov [oldstdout], ax`	123	`mov [oldstdout], ax`
101	`/* redirect the stdout handle */`	124	`/* redirect the stdout handle */`
102	`mov bx, [handle] /* dst handle */`	125	`mov bx, [handle] /* dst handle */`
103	`mov cx, 1 /* src handle (1=stdout) */`	126	`mov cx, 1 /* src handle (1=stdout) */`
104	`mov ah, 0x46 /* redirect a handle */`	127	`mov ah, 0x46 /* redirect a handle */`
105	`int 0x21`	128	`int 0x21`
106	`/* close the original file handle (no longer needed) */`	129	`/* close the original file handle (no longer needed) */`
107	`mov ah, 0x3e /* close a file handle (handle in BX) */`	130	`mov ah, 0x3e /* close a file handle (handle in BX) */`
108	`int 0x21`	131	`int 0x21`
109	`DONE:`	132	`DONE:`
110	`pop si`	133	`pop si`
111	`pop dx`	134	`pop dx`
112	`pop cx`	135	`pop cx`
113	`pop bx`	136	`pop bx`
114	`pop ax`	137	`pop ax`
115	`}`	138	`}`
116	`if (errcode != 0) {`	139	`if (errcode != 0) {`
117	`outputnl(doserr(errcode));`	140	`outputnl(doserr(errcode));`
118	`return(-1);`	141	`return(-1);`
119	`}`	142	`}`
120	`}`	143	`}`
121		144
122	`return(0);`	145	`return(0);`
123	`}`	146	`}`
124		147
125		148
126	`/* restores previous stdout/stdin handlers if they have been redirected */`	149	`/* restores previous stdout/stdin handlers if they have been redirected */`
127	`void redir_revert(void) {`	150	`void redir_revert(void) {`
128	`_asm {`	151	`_asm {`
129	`/* if oldstdout is 0xffff then not redirected */`	152	`/* if oldstdout is 0xffff then not redirected */`
130	`cmp word ptr [oldstdout], 0xffff`	153	`cmp word ptr [oldstdout], 0xffff`
131	`je DONE`	154	`je DONE`
132	`/* redirect the stdout handle */`	155	`/* redirect the stdout handle */`
133	`mov bx, [oldstdout] /* dst handle */`	156	`mov bx, [oldstdout] /* dst handle */`
134	`mov cx, 1 /* src handle (1=stdout) */`	157	`mov cx, 1 /* src handle (1=stdout) */`
135	`mov ah, 0x46 /* redirect a handle */`	158	`mov ah, 0x46 /* redirect a handle */`
136	`int 0x21`	159	`int 0x21`
137	`mov [oldstdout], 0xffff`	160	`mov [oldstdout], 0xffff`
138	`DONE:`	161	`DONE:`
139	`}`	162	`}`
140	`}`	163	`}`
141		164

Subversion Repositories SvarDOS

(root)/svarcom/trunk/redir.c – Rev 402 → 421