WebSVN – SvarDOS – Diff – /svarcom/trunk/env.c


/* This file is part of the SvarCOM project and is published under the terms
 * of the MIT license.
 *
 * Copyright (C) 2021-2022 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.
 */
 
/*
 * routines used to manipulate the environment block
 */
 
#include <i86.h>
#include <string.h>
 
#include "env.h"
 
/* looks for varname in environment block and returns a far ptr to it if
 * found, NULL otherwise. varname MUST be in upper-case and MUST be terminated
 * by either a = sign or a NULL terminator */
char far *env_lookup(unsigned short env_seg, const char *varname) {
  char far *env = MK_FP(env_seg, 0);
  int i;
  for (;;) {
    /* is this it? */
    for (i = 0;; i++) {
      if ((varname[i] == '=') || (varname[i] == 0)) {
        if (env[i] == '=') return(env); /* FOUND! */
        break; /* else look for next string */
      }
      if (varname[i] != env[i]) break;
    }
    /* move env to end of current string */
    while (*env != 0) env++;
    /* if there's another trailing zero, then that is the end of environment */
    env++;
    if (*env == 0) return(NULL);
  }
}
 
 
/* almost identical to env_lookup(), but instead of returning a pointer
 * to the 'NAME=value' string, it returns a pointer to value (or NULL if
 * var not found) */
char far *env_lookup_val(unsigned short env_seg, const char *varname) {
  char far *r = env_lookup(env_seg, varname);
  if (r == NULL) return(NULL);
  /* find '=' or end of string */
  for (;;) {
    if (*r == '=') return(r + 1);
    if (*r == 0) return(r);
    r++;
  }
}
 
 
/* locates the value of env variable varname and copies it to result, up to
 * ressz bytes (incl. the NULL terminator). returns the length of the value on
 * success, 0 if var not found or couldn't fit in ressz). */
unsigned short env_lookup_valcopy(char *res, unsigned short ressz, unsigned short env_seg, const char *varname) {
  unsigned short i;
  char far *v = env_lookup_val(env_seg, varname);
  if (v == NULL) return(0);
  for (i = 0;; i++) {
    if (ressz-- == 0) return(0);
    res[i] = v[i];
    if (res[i] == 0) return(i);
  }
}
 
 
/* returns the size, in bytes, of the allocated environment block */
unsigned short env_allocsz(unsigned short env_seg) {
  unsigned short far *mcbsz = MK_FP(env_seg - 1, 3); /* block size is a word at offset +3 in the MCB */
  return(*mcbsz * 16); /* return size in bytes, not paragraphs */
}
 
 
/* remove a variable from environment, if present. returns 0 on success, non-zero if variable not found */
int env_dropvar(unsigned short env_seg, const char *varname) {
  unsigned short blocksz, traillen;
  unsigned short len;
  char far *varptr = env_lookup(env_seg, varname);
 
  /* if variable not found in environment, quit now */
  if (varptr == NULL) return(-1);
 
  for (len = 0; varptr[len] != 0; len++); /* compute length of variable (without trailing null) */
  blocksz = env_allocsz(env_seg);           /* total environment size */
  traillen = blocksz - (FP_OFF(varptr) + len + 1); /* how much bytes are present after the variable */
  _fmemset(varptr, 0, len);               /* zero out the variable */
  if (traillen != 0) {
    _fmemmove(varptr, varptr + len + 1, traillen); /* move rest of memory */
  }
  return(0);
}
 
 
/* Writes a variable to environment block. The variable must in the form
 * "VARNAME=value". If variable is already present in the environment block,
 * then the value will be updated. If the new value is empty, then the
 * existing variable (if any) is removed.
 * VARNAME *MUST* be all-uppercase.
 *
 * This function returns:
 *   ENV_SUCCESS = success
 *   ENV_NOTENOM = not enough available space in memory block
 *   ENV_INVSYNT = invalid syntax
 */
int env_setvar(unsigned short env_seg, const char *v) {
  unsigned short envlen;
  unsigned short envfree;
  unsigned short vlen, veqpos;
  char far *env = MK_FP(env_seg, 0);
 
  /* remove variable from environment, if already set */
  env_dropvar(env_seg, v);
 
  /* compute v length and find the position of the eq sign */
  veqpos = 0xffff;
  for (vlen = 0; v[vlen] != 0; vlen++) {
    if (v[vlen] == '=') {
      if (veqpos != 0xffff) return(ENV_INVSYNT); /* equal sign is forbidden in value */
      veqpos = vlen;
    }
  }
 
  /* if variable empty, stop here */
  if (veqpos == vlen - 1) return(ENV_SUCCESS);
 
  /* compute current size of the environment */
  for (envlen = 0; env[envlen] != 0; envlen++) {
    while (env[envlen] != 0) envlen++; /* consume a string */
  }
 
  /* compute free space available in environment */
  envfree = env_allocsz(env_seg);
  envfree -= envlen;
  envfree -= 1; /* 1 byte for the environment's NULL terminator */
 
  /* do I have enough env space for the new var? */
  if (envfree < vlen + 1) return(ENV_NOTENOM);
 
  /* write the new variable (with its NULL terminator) to environment tail */
  _fmemcpy(env + envlen, v, vlen + 1);
 
  /* add the environment's NULL terminator */
  env[envlen + vlen + 1] = 0;
 
  return(ENV_SUCCESS);
}
 

Subversion Repositories SvarDOS

(root)/svarcom/trunk/env.c – Rev 436 → 570

Rev 436		Rev 570
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) 2021-2022 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	`/*`	25	`/*`
26	`* routines used to manipulate the environment block`	26	`* routines used to manipulate the environment block`
27	`*/`	27	`*/`
28		28
29	`#include <i86.h>`	29	`#include <i86.h>`
30	`#include <string.h>`	30	`#include <string.h>`
31		31
32	`#include "env.h"`	32	`#include "env.h"`
33		33
34	`/* looks for varname in environment block and returns a far ptr to it if`	34	`/* looks for varname in environment block and returns a far ptr to it if`
35	`* found, NULL otherwise. varname MUST be in upper-case and MUST be terminated`	35	`* found, NULL otherwise. varname MUST be in upper-case and MUST be terminated`
36	`* by either a = sign or a NULL terminator */`	36	`* by either a = sign or a NULL terminator */`
37	`char far env_lookup(unsigned short env_seg, const char varname) {`	37	`char far env_lookup(unsigned short env_seg, const char varname) {`
38	`char far *env = MK_FP(env_seg, 0);`	38	`char far *env = MK_FP(env_seg, 0);`
39	`int i;`	39	`int i;`
40	`for (;;) {`	40	`for (;;) {`
41	`/* is this it? */`	41	`/* is this it? */`
42	`for (i = 0;; i++) {`	42	`for (i = 0;; i++) {`
43	`if ((varname[i] == '=') \|\| (varname[i] == 0)) {`	43	`if ((varname[i] == '=') \|\| (varname[i] == 0)) {`
44	`if (env[i] == '=') return(env); /* FOUND! */`	44	`if (env[i] == '=') return(env); /* FOUND! */`
45	`break; /* else look for next string */`	45	`break; /* else look for next string */`
46	`}`	46	`}`
47	`if (varname[i] != env[i]) break;`	47	`if (varname[i] != env[i]) break;`
48	`}`	48	`}`
49	`/* move env to end of current string */`	49	`/* move env to end of current string */`
50	`while (*env != 0) env++;`	50	`while (*env != 0) env++;`
51	`/* if there's another trailing zero, then that is the end of environment */`	51	`/* if there's another trailing zero, then that is the end of environment */`
52	`env++;`	52	`env++;`
53	`if (*env == 0) return(NULL);`	53	`if (*env == 0) return(NULL);`
54	`}`	54	`}`
55	`}`	55	`}`
56		56
57		57
58	`/* almost identical to env_lookup(), but instead of returning a pointer`	58	`/* almost identical to env_lookup(), but instead of returning a pointer`
59	`* to the 'NAME=value' string, it returns a pointer to value (or NULL if`	59	`* to the 'NAME=value' string, it returns a pointer to value (or NULL if`
60	`* var not found) */`	60	`* var not found) */`
61	`char far env_lookup_val(unsigned short env_seg, const char varname) {`	61	`char far env_lookup_val(unsigned short env_seg, const char varname) {`
62	`char far *r = env_lookup(env_seg, varname);`	62	`char far *r = env_lookup(env_seg, varname);`
63	`if (r == NULL) return(NULL);`	63	`if (r == NULL) return(NULL);`
64	`/* find '=' or end of string */`	64	`/* find '=' or end of string */`
65	`for (;;) {`	65	`for (;;) {`
66	`if (*r == '=') return(r + 1);`	66	`if (*r == '=') return(r + 1);`
67	`if (*r == 0) return(r);`	67	`if (*r == 0) return(r);`
68	`r++;`	68	`r++;`
69	`}`	69	`}`
-		70	`}`
-		71
-		72
-		73	`/* locates the value of env variable varname and copies it to result, up to`
-		74	`* ressz bytes (incl. the NULL terminator). returns the length of the value on`
-		75	`* success, 0 if var not found or couldn't fit in ressz). */`
-		76	`unsigned short env_lookup_valcopy(char res, unsigned short ressz, unsigned short env_seg, const char varname) {`
-		77	`unsigned short i;`
-		78	`char far *v = env_lookup_val(env_seg, varname);`
-		79	`if (v == NULL) return(0);`
-		80	`for (i = 0;; i++) {`
-		81	`if (ressz-- == 0) return(0);`
-		82	`res[i] = v[i];`
-		83	`if (res[i] == 0) return(i);`
-		84	`}`
70	`}`	85	`}`
71		86
72		87
73	`/* returns the size, in bytes, of the allocated environment block */`	88	`/* returns the size, in bytes, of the allocated environment block */`
74	`unsigned short env_allocsz(unsigned short env_seg) {`	89	`unsigned short env_allocsz(unsigned short env_seg) {`
75	`unsigned short far mcbsz = MK_FP(env_seg - 1, 3); / block size is a word at offset +3 in the MCB */`	90	`unsigned short far mcbsz = MK_FP(env_seg - 1, 3); / block size is a word at offset +3 in the MCB */`
76	`return(mcbsz 16); /* return size in bytes, not paragraphs */`	91	`return(mcbsz 16); /* return size in bytes, not paragraphs */`
77	`}`	92	`}`
78		93
79		94
80	`/* remove a variable from environment, if present. returns 0 on success, non-zero if variable not found */`	95	`/* remove a variable from environment, if present. returns 0 on success, non-zero if variable not found */`
81	`int env_dropvar(unsigned short env_seg, const char *varname) {`	96	`int env_dropvar(unsigned short env_seg, const char *varname) {`
82	`unsigned short blocksz, traillen;`	97	`unsigned short blocksz, traillen;`
83	`unsigned short len;`	98	`unsigned short len;`
84	`char far *varptr = env_lookup(env_seg, varname);`	99	`char far *varptr = env_lookup(env_seg, varname);`
85		100
86	`/* if variable not found in environment, quit now */`	101	`/* if variable not found in environment, quit now */`
87	`if (varptr == NULL) return(-1);`	102	`if (varptr == NULL) return(-1);`
88		103
89	`for (len = 0; varptr[len] != 0; len++); /* compute length of variable (without trailing null) */`	104	`for (len = 0; varptr[len] != 0; len++); /* compute length of variable (without trailing null) */`
90	`blocksz = env_allocsz(env_seg); /* total environment size */`	105	`blocksz = env_allocsz(env_seg); /* total environment size */`
91	`traillen = blocksz - (FP_OFF(varptr) + len + 1); /* how much bytes are present after the variable */`	106	`traillen = blocksz - (FP_OFF(varptr) + len + 1); /* how much bytes are present after the variable */`
92	`_fmemset(varptr, 0, len); /* zero out the variable */`	107	`_fmemset(varptr, 0, len); /* zero out the variable */`
93	`if (traillen != 0) {`	108	`if (traillen != 0) {`
94	`_fmemmove(varptr, varptr + len + 1, traillen); /* move rest of memory */`	109	`_fmemmove(varptr, varptr + len + 1, traillen); /* move rest of memory */`
95	`}`	110	`}`
96	`return(0);`	111	`return(0);`
97	`}`	112	`}`
98		113
99		114
100	`/* Writes a variable to environment block. The variable must in the form`	115	`/* Writes a variable to environment block. The variable must in the form`
101	`* "VARNAME=value". If variable is already present in the environment block,`	116	`* "VARNAME=value". If variable is already present in the environment block,`
102	`* then the value will be updated. If the new value is empty, then the`	117	`* then the value will be updated. If the new value is empty, then the`
103	`* existing variable (if any) is removed.`	118	`* existing variable (if any) is removed.`
104	`* VARNAME MUST be all-uppercase.`	119	`* VARNAME MUST be all-uppercase.`
105	`*`	120	`*`
106	`* This function returns:`	121	`* This function returns:`
107	`* ENV_SUCCESS = success`	122	`* ENV_SUCCESS = success`
108	`* ENV_NOTENOM = not enough available space in memory block`	123	`* ENV_NOTENOM = not enough available space in memory block`
109	`* ENV_INVSYNT = invalid syntax`	124	`* ENV_INVSYNT = invalid syntax`
110	`*/`	125	`*/`
111	`int env_setvar(unsigned short env_seg, const char *v) {`	126	`int env_setvar(unsigned short env_seg, const char *v) {`
112	`unsigned short envlen;`	127	`unsigned short envlen;`
113	`unsigned short envfree;`	128	`unsigned short envfree;`
114	`unsigned short vlen, veqpos;`	129	`unsigned short vlen, veqpos;`
115	`char far *env = MK_FP(env_seg, 0);`	130	`char far *env = MK_FP(env_seg, 0);`
116		131
117	`/* remove variable from environment, if already set */`	132	`/* remove variable from environment, if already set */`
118	`env_dropvar(env_seg, v);`	133	`env_dropvar(env_seg, v);`
119		134
120	`/* compute v length and find the position of the eq sign */`	135	`/* compute v length and find the position of the eq sign */`
121	`veqpos = 0xffff;`	136	`veqpos = 0xffff;`
122	`for (vlen = 0; v[vlen] != 0; vlen++) {`	137	`for (vlen = 0; v[vlen] != 0; vlen++) {`
123	`if (v[vlen] == '=') {`	138	`if (v[vlen] == '=') {`
124	`if (veqpos != 0xffff) return(ENV_INVSYNT); /* equal sign is forbidden in value */`	139	`if (veqpos != 0xffff) return(ENV_INVSYNT); /* equal sign is forbidden in value */`
125	`veqpos = vlen;`	140	`veqpos = vlen;`
126	`}`	141	`}`
127	`}`	142	`}`
128		143
129	`/* if variable empty, stop here */`	144	`/* if variable empty, stop here */`
130	`if (veqpos == vlen - 1) return(ENV_SUCCESS);`	145	`if (veqpos == vlen - 1) return(ENV_SUCCESS);`
131		146
132	`/* compute current size of the environment */`	147	`/* compute current size of the environment */`
133	`for (envlen = 0; env[envlen] != 0; envlen++) {`	148	`for (envlen = 0; env[envlen] != 0; envlen++) {`
134	`while (env[envlen] != 0) envlen++; /* consume a string */`	149	`while (env[envlen] != 0) envlen++; /* consume a string */`
135	`}`	150	`}`
136		151
137	`/* compute free space available in environment */`	152	`/* compute free space available in environment */`
138	`envfree = env_allocsz(env_seg);`	153	`envfree = env_allocsz(env_seg);`
139	`envfree -= envlen;`	154	`envfree -= envlen;`
140	`envfree -= 1; /* 1 byte for the environment's NULL terminator */`	155	`envfree -= 1; /* 1 byte for the environment's NULL terminator */`
141		156
142	`/* do I have enough env space for the new var? */`	157	`/* do I have enough env space for the new var? */`
143	`if (envfree < vlen + 1) return(ENV_NOTENOM);`	158	`if (envfree < vlen + 1) return(ENV_NOTENOM);`
144		159
145	`/* write the new variable (with its NULL terminator) to environment tail */`	160	`/* write the new variable (with its NULL terminator) to environment tail */`
146	`_fmemcpy(env + envlen, v, vlen + 1);`	161	`_fmemcpy(env + envlen, v, vlen + 1);`
147		162
148	`/* add the environment's NULL terminator */`	163	`/* add the environment's NULL terminator */`
149	`env[envlen + vlen + 1] = 0;`	164	`env[envlen + vlen + 1] = 0;`
150		165
151	`return(ENV_SUCCESS);`	166	`return(ENV_SUCCESS);`
152	`}`	167	`}`
153		168