commit: a808568045b05c24347b8a26e523b00833d841dd
parent: c2b6c7fffe0902896cf7e5d3188a14909b80acf6
author: z0noxz <chris@noxz.tech>
date: Wed, 8 Aug 2018 20:46:45 +0200
port everything to c instead of POSIX sh
5 files changed, 129 insertions(+), 79 deletions(-)
diff --git a/Makefile b/Makefile
@@ -0,0 +1,33 @@
+.POSIX:
+
+include config.mk
+
+SRC = cidr2ip.c
+OBJ = $(SRC:.c=.o)
+
+all: options cidr2ip
+
+options:
+ @echo cidr2ip build options:
+ @echo "CC = $(CC)"
+
+.c.o:
+ $(CC) $(STCFLAGS) -c $<
+
+$(OBJ): config.mk
+
+cidr2ip: $(OBJ)
+ $(CC) -g -o $@ $(OBJ) $(STLDFLAGS)
+
+clean:
+ rm -f cidr2ip $(OBJ)
+
+install: cidr2ip
+ mkdir -p /usr/local/bin
+ cp -f cidr2ip /usr/local/bin
+ chmod 755 /usr/local/bin/cidr2ip
+
+uninstall:
+ rm -f /usr/local/bin/cidr2ip
+
+.PHONY: all options clean install uninstall
diff --git a/README.md b/README.md
@@ -1,9 +1,18 @@
-# cidr2ip
-Converts CIDR to IPADDRESS
+cidr2ip
+======
+`cidr2ip` is a small and simple program for converting a CIDR into ip (mask).
-install using `cp ./cidr2ip /usr/local/bin` or similar.
+Installation
+------------
+Edit config.mk to match your local setup (cidr2ip is installed into the
+/usr/local namespace by default), then simply enter the following command to
+install (if necessary as root):
+
+ make clean install
+
+Example usage of cidr2ip
+------------------------
+Print a complete CIDR to ip conversion table
+
+ for i in {1..32}; do printf '\\%-5s' $i; cidr2ip $i;done
-## print complete table
-```
-for i in {1..32}; do printf '\\%-5s' $i; cidr2ip $i;done
-```
diff --git a/cidr2ip b/cidr2ip
@@ -1,72 +0,0 @@
-#!/bin/sh
-license='
-Converts CIDR to IPADDRESS
-Copyright (C) 2018 z0noxz, <chris@noxz.tech>
-
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program. If not, see <http://www.gnu.org/licenses/>.
-'
-
-do_cidr2ip() {
-
- # variable declaration
- cidr=$1
- cidr_invert=$((32-cidr))
- mask=$((4294967295 >> cidr_invert << cidr_invert))
- result=""
- base=256
- i=0
-
- # base convert decimal mask to base-256
- while [ "$mask" -ne 0 ]; do
- result=$(printf '%-4s%s' $((mask % base)) "$result")
- mask=$((mask / base))
- done
-
- # output as an ip
- for item in $result; do
- printf '%d' "$item"
- i=$((i+1))
- if [ "$i" -lt 4 ]; then
- printf '.'
- else
- printf '\n'
- fi
- done
-
- # success
- return 0
-}
-
-# read from stdin if applicable
-x="$1"
-if ! [ -t 0 ]; then
- while read -r line; do
- x="$line"
- done
-fi
-
-# check if input is a CIDR, then process it
-if [ "$x" -eq "$x" ] 2> /dev/null && [ "$x" -le 32 ] && [ "$x" -gt 0 ]; then
- do_cidr2ip "$x" && exit 0
-fi
-
-# if all fails print usage
-program_name="${0##*/}"
-printf 'Usage: %s CIDR
-
-LICENSE NOTICE
-%s
-' "$program_name" "$license" >&2
-
-exit 1
diff --git a/cidr2ip.c b/cidr2ip.c
@@ -0,0 +1,65 @@
+/*
+ * Converts CIDR to IPADDRESS
+ * Copyright (C) 2018 z0noxz, <chris@noxz.tech>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv) {
+ int ip, cidr, input_size;
+ int buffer_size = 80;
+ unsigned char mask[4];
+ char buffer[buffer_size];
+ char *input;
+
+ /* validate input from STDIN */
+ if (!isatty(fileno(stdin)) && fgets(buffer, buffer_size, stdin) != NULL) {
+ input_size = strlen(buffer);
+ input = malloc(input_size);
+ input[0] = '\0';
+ strcat(input, buffer);
+
+ /* validate input from CLI */
+ } else if (argc == 2) {
+ input_size = strlen(argv[1]);
+ input = malloc(input_size);
+ input[0] = '\0';
+ strcat(input, argv[1]);
+
+ /* no valid input, so show usage */
+ } else {
+ fprintf(stderr, "usage: cidr2ip CIDR\n");
+ return 1;
+ }
+
+ if (sscanf(input, "%d", &cidr) == 1 && cidr >= 1 && cidr <= 32) {
+ ip = 4294967295 >> (32-cidr) << (32-cidr);
+ mask[0] = (ip >> 0) & 0xff;
+ mask[1] = (ip >> 8) & 0xff;
+ mask[2] = (ip >> 16) & 0xff;
+ mask[3] = (ip >> 24) & 0xff;
+ } else {
+ fprintf(stderr, "error: not a CIDR\n");
+ return 1;
+ }
+
+ /* finally print the mask */
+ printf("%d.%d.%d.%d\n", mask[3], mask[2], mask[1], mask[0]);
+ return 0;
+}
diff --git a/config.mk b/config.mk
@@ -0,0 +1,15 @@
+# ztatus version
+VERSION = 0.1.1
+
+# paths
+PREFIX = /usr/local
+MANPREFIX = $(PREFIX)/share/man
+
+# flags
+CFLAGS = -Wall -O3 -pedantic
+CPPFLAGS = -DVERSION=\"$(VERSION)\" -D_DEFAULT_SOURCE -D_XOPEN_SOURCE=600
+STCFLAGS = $(CPPFLAGS) $(CFLAGS)
+STLDFLAGS = $(LDFLAGS)
+
+# compiler and linker
+CC = gcc
