initial commit

build.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+cc -static -Wall -Werror -o ddns ddns.c
+install -o www -g www -m 0500 ddns /var/www/ddns

ddns.c

@@ -0,0 +1,137 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <err.h>
+
+#define SEP '='
+#define IP_LEN 16
+#define IP_FILE "ip.txt"
+#define TOKEN "<empty>"
+
+void free_arr(void *arr) {
+        uintptr_t *a = arr;
+        while(*a) {
+                free((void*)*a++);
+        }
+        free(arr);
+}
+
+char **parse(const char *str) {
+        const char *s = str;
+        char *qs, *token;
+        char **arr = NULL;
+        int c = 1;
+        qs = strdup(s);
+        while((token = strsep(&qs, "&")) != NULL) {
+                c++;
+                if(arr == NULL) {
+                        arr = malloc(c*sizeof(char *));
+                        if(arr == NULL)
+                                break;
+                } else {
+                        arr = realloc(arr, c*sizeof(char *));
+                        if(arr == NULL)
+                                break;
+                }
+                arr[c-1] = NULL;
+                arr[c-2] = strdup(token);
+        }
+        free(qs);
+        return(arr);
+}
+
+void header() {
+        puts("Status: 200 OK\r");
+        puts("Content-Type: text/html\r");
+        puts("\r");
+}
+
+int ctb(unsigned char a, unsigned char b) {
+        unsigned char c = ~(a ^ b);
+        c &= c >> 4;
+        c &= c >> 2;
+        c &= c >> 1;
+        return((int)c);
+}
+
+int ctc(const char *a, const char *b) {
+        if(strlen(a) != strlen(b)) {
+                return(0);
+        }
+        const char *x = a, *y = b;
+        char v = 0;
+        while(*x)
+                v |= *x++ ^ *y++;
+        return(ctb(v, 0));
+}
+
+int set_ip(char *env, int fd) {
+        char *ip, *token, *tmp;
+        int ret = -1, len = 0;
+        char **arg = parse(env);
+        char **arr = arg;
+        if(arg == NULL)
+                return(0);
+        for(; *arr; arr++) {
+                if(strncmp(*arr, "ip", 2) == 0) {
+                        tmp = strchr(*arr, SEP);
+                        if(++tmp == NULL)  
+                                continue;
+                        ip = strdup(tmp);
+                } else if(strncmp(*arr, "token", 5) == 0) {
+                        tmp = strchr(*arr, SEP);
+                        if(++tmp == NULL)  
+                                continue;
+                        token = strdup(tmp);
+                }
+        }
+        tmp = NULL;
+        free_arr(arg);
+        if(ctc(token, TOKEN) == 1) {
+                len = strlen(ip);
+                if(len >= IP_LEN-1)
+                        len = IP_LEN-1;
+                write(fd, ip, len);
+                close(fd);
+        } else
+                ret = 1;
+        free(token);
+        free(ip);
+        return(ret);
+}
+
+char *err_msg[2] = {"wrong input", "wrong token"};
+
+int main(void) {
+        char *env;
+        char ip[IP_LEN];
+        int errn = 0, len = 0;
+        int rfd = open(IP_FILE, O_RDONLY|O_SHLOCK);
+        if(read(rfd, &ip, IP_LEN) <= 0)
+                ip[0] = '\0';
+        close(rfd);
+        ip[IP_LEN] = '\0';
+        int wfd = open(IP_FILE, O_WRONLY|O_CREAT|O_TRUNC|O_EXLOCK);
+        if(pledge("stdio", NULL) == -1) 
+                err(EXIT_FAILURE, "pledge");
+        env = getenv("QUERY_STRING");
+        header();
+        if(env != NULL) {
+                if((errn = set_ip(env, wfd)) >= 0)
+                        puts(err_msg[errn]);
+                else
+                        puts("ok");
+        } else {
+                len = strlen(ip);
+                write(wfd, ip, len);
+                close(wfd);
+                if(len > 1)
+                        puts(ip);
+                else
+                        puts("empty");
+        }
+        return(EXIT_SUCCESS);
+}

httpd.conf

@@ -0,0 +1,7 @@
+server "localhost" {
+  listen on * port 80
+  location "/ddns/*" {
+    fastcgi
+    root "/"
+  }
+}

install.sh

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+dir=/var/www/ddns
+ip=ip.txt
+ip_file=${dir}/${ip}
+mkdir -p ${dir}
+touch ${ip_file}
+chmod 0600 ${ip_file}
+chown www:www ${ip_file}
+rcctl enable slowcgi
+rcctl start slowcgi
+rcctl enable httpd
+rcctl start httpd