--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/a5.c	Sun Apr 01 17:03:01 2012 +0900
@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <string.h>
+
+#define AFTER5PATH	"./after5.cgi"
+
+int main(int argc, char *argv[])
+{
+  char *path=malloc(strlen(argv[0]));
+  char *p;
+  uid_t euid = geteuid();
+  struct stat st;
+  if (0 == euid) {
+    fputs("Do not call this program with suid 0\n", stderr);
+    exit(0);
+  }
+  strcpy(path, argv[0]);
+  p = strrchr(path, '/');
+  if (p) {
+    *p = '\0';
+  } else {
+    fputs("Cannot detect the directory where this program located.\n", stderr);
+    exit(1);
+  }
+  
+  if (-1 == chdir(path)) {
+    fprintf(stderr, "Cannot chdir to %s\n", path);
+    exit(2);
+  }
+  if (0 > stat(AFTER5PATH, &st)) {
+    fprintf(stderr, "Cannot access %s\n", AFTER5PATH);
+    exit(3);
+  }
+  if (st.st_uid != euid) {
+    fputs("UID of cgi program mismatch\n", stderr);
+    fputs("Do chown so that wrapper and cgi files' uid matches.\n", stderr);
+    exit(4);
+  }
+  if (0 > stat(".", &st)) {
+    fputs("Cannot stat current directory\n", stderr);
+    fputs("Please ensure installed directory is readable.\n", stderr);
+    exit(5);
+  }
+  if (st.st_uid != euid) {
+    fputs("UID of directory mismatch\n", stderr);
+    fputs("Do chown so that wrapper and directorys' uid matches.\n", stderr);
+    exit(6);
+  }
+  if (st.st_mode & (S_IWGRP | S_IWOTH)) {
+    fputs("This directory is writable for group/others.\n", stderr);
+    fputs("Do chmod og-w for installed directory.\n", stderr);
+    exit(7);
+  }
+  execv("./after5.cgi", argv);
+}