mirror of
https://github.com/lcn2/calc.git
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133 lines
2.7 KiB
C
133 lines
2.7 KiB
C
/*
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* Copyright (c) 1997 David I. Bell
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* Permission is granted to use, distribute, or modify this source,
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* provided that this copyright notice remains intact.
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*
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* Arbitrary precision calculator.
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*/
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#include <stdio.h>
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#include <ctype.h>
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#include "calc.h"
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#include "conf.h"
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#include "have_unistd.h"
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#if defined(HAVE_UNISTD_H)
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#include <unistd.h>
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#endif
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/*
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* some help topics are symbols, so we alias them to nice filenames
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*/
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static struct help_alias {
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char *topic;
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char *filename;
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} halias[] = {
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{"=", "address"},
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{"->", "arrow"},
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{"=", "assign"},
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{"*", "dereference"},
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{".", "oldvalue"},
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{"%", "mod"},
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{"//", "quo"},
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{NULL, NULL}
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};
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/*
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* external values
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*/
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extern char *pager; /* $PAGER or default */
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/*
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* givehelp - display a help file
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*
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* given:
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* type the type of help to give, NULL => index
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*/
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void
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givehelp(char *type)
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{
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struct help_alias *p; /* help alias being considered */
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char *helpcmd; /* what to execute to print help */
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char *c;
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/*
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* check permissions to see if we are allowed to help
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*/
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if (!allow_exec || !allow_read) {
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fprintf(stderr,
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"sorry, help is only allowed with -m mode 5 or 7\n");
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return;
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}
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/* catch the case where we just print the index */
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if (type == NULL) {
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type = DEFAULTCALCHELP; /* the help index file */
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}
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/* alias the type of help, if needed */
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for (p=halias; p->topic; ++p) {
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if (strcmp(type, p->topic) == 0) {
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type = p->filename;
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break;
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}
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}
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/*
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* sanity check on name
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*/
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/* look for /. or a leading . */
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if (strstr(type, "/.") != NULL || type[0] == '.') {
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fprintf(stderr, "bad help name\n");
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return;
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}
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/* look for chars that could be shell meta chars */
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for (c = type; *c; ++c) {
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switch ((int)*c) {
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case '+':
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case ',':
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case '-':
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case '.':
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case '/':
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case '_':
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break;
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default:
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if (!isascii((int)*c) || !isalnum((int)*c)) {
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fprintf(stderr, "bogus char in help name\n");
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return;
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}
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break;
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}
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}
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/* form the help command name */
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helpcmd = (char *)malloc(
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sizeof("if [ ! -r \"")+sizeof(HELPDIR)+1+strlen(type)+
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sizeof("\" ];then ")+
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strlen(pager)+1+1+sizeof(HELPDIR)+1+strlen(type)+1+1+
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sizeof("elif [ ! -r \"")+sizeof(CUSTOMHELPDIR)+1+strlen(type)+
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sizeof("\" ];then ")+
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strlen(pager)+1+1+sizeof(CUSTOMHELPDIR)+1+strlen(type)+1+1+
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sizeof(";else ")+sizeof(ECHO)+
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sizeof("echo no such help, try: help help;fi")+1);
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sprintf(helpcmd,
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"if [ -r \"%s/%s\" ];then %s \"%s/%s\";"
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"elif [ -r \"%s/%s\" ];then %s \"%s/%s\";"
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"else %s no such help, try: help help;fi",
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HELPDIR, type, pager, HELPDIR, type,
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CUSTOMHELPDIR, type, pager, CUSTOMHELPDIR, type, ECHO);
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if (conf->calc_debug & CALCDBG_SYSTEM) {
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printf("%s\n", helpcmd);
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}
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/* execute the help command */
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system(helpcmd);
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free(helpcmd);
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}
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