Release calc version 2.10.3t5.45

help.c

@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 1997 David I. Bell
+ * Permission is granted to use, distribute, or modify this source,
+ * provided that this copyright notice remains intact.
+ *
+ * Arbitrary precision calculator.
+ */
+
+#include <stdio.h>
+#include <ctype.h>
+
+#include "calc.h"
+#include "conf.h"
+
+#include "have_unistd.h"
+#if defined(HAVE_UNISTD_H)
+#include <unistd.h>
+#endif
+
+
+/*
+ * some help topics are symbols, so we alias them to nice filenames
+ */
+static struct help_alias {
+	char *topic;
+	char *filename;
+} halias[] = {
+	{"=", "address"},
+	{"->", "arrow"},
+	{"=", "assign"},
+	{"*", "dereference"},
+	{".", "oldvalue"},
+	{"%", "mod"},
+	{"//", "quo"},
+	{NULL, NULL}
+};
+
+
+/*
+ * external values
+ */
+extern char *pager;		/* $PAGER or default */
+
+
+/*
+ * givehelp - display a help file
+ *
+ * given:
+ *	type		the type of help to give, NULL => index
+ */
+void
+givehelp(char *type)
+{
+	struct help_alias *p;	/* help alias being considered */
+	char *helpcmd;		/* what to execute to print help */
+	char *c;
+
+	/*
+	 * check permissions to see if we are allowed to help
+	 */
+	if (!allow_exec || !allow_read) {
+		fprintf(stderr,
+		    "sorry, help is only allowed with -m mode 5 or 7\n");
+		return;
+	}
+
+	/* catch the case where we just print the index */
+	if (type == NULL) {
+		type = DEFAULTCALCHELP;		/* the help index file */
+	}
+
+	/* alias the type of help, if needed */
+	for (p=halias; p->topic; ++p) {
+		if (strcmp(type, p->topic) == 0) {
+			type = p->filename;
+			break;
+		}
+	}
+
+	/*
+	 * sanity check on name
+	 */
+	/* look for /. or a leading . */
+	if (strstr(type, "/.") != NULL || type[0] == '.') {
+		fprintf(stderr, "bad help name\n");
+		return;
+	}
+	/* look for chars that could be shell meta chars */
+	for (c = type; *c; ++c) {
+		switch ((int)*c) {
+		case '+':
+		case ',':
+		case '-':
+		case '.':
+		case '/':
+		case '_':
+			break;
+		default:
+			if (!isascii((int)*c) || !isalnum((int)*c)) {
+				fprintf(stderr, "bogus char in help name\n");
+				return;
+			}
+			break;
+		}
+	}
+
+
+	/* form the help command name */
+	helpcmd = (char *)malloc(
+		sizeof("if [ ! -r \"")+sizeof(HELPDIR)+1+strlen(type)+
+		sizeof("\" ];then ")+
+		strlen(pager)+1+1+sizeof(HELPDIR)+1+strlen(type)+1+1+
+		sizeof("elif [ ! -r \"")+sizeof(CUSTOMHELPDIR)+1+strlen(type)+
+		sizeof("\" ];then ")+
+		strlen(pager)+1+1+sizeof(CUSTOMHELPDIR)+1+strlen(type)+1+1+
+		sizeof(";else ")+sizeof(ECHO)+
+		sizeof("echo no such help, try: help help;fi")+1);
+	sprintf(helpcmd,
+	    "if [ -r \"%s/%s\" ];then %s \"%s/%s\";"
+	    "elif [ -r \"%s/%s\" ];then %s \"%s/%s\";"
+	    "else %s no such help, try: help help;fi",
+	    HELPDIR, type, pager, HELPDIR, type,
+	    CUSTOMHELPDIR, type, pager, CUSTOMHELPDIR, type, ECHO);
+	if (conf->calc_debug > 0) {
+		printf("%s\n", helpcmd);
+		sleep(3);
+	}
+
+	/* execute the help command */
+	system(helpcmd);
+	free(helpcmd);
+}
+