Re: [bug-inetutils] [patch] inetd: set environment variables for remote host, ip and local port

[Sergey Poznyakoff]

Hello,

Based on Dirk's patch, I have installed the following modifications
to inetd. Passing the environment variables is enabled
by --environment option. The TCP.*HOST variables are set only if the
--resolve option has been specified. 

The functionality is limited to IPv4 TCP nowait connection, but I
believe it should be expanded to other connection types as well.

In addition, this patch allows to pass numeric port numbers in
'service' field.

Regards,
Sergey

Index: inetd.c
===================================================================
RCS file: /cvsroot/inetutils/inetutils/inetd/inetd.c,v
retrieving revision 1.32
diff -p -u -r1.32 inetd.c
--- inetd.c     20 Apr 2006 08:16:11 -0000      1.32
+++ inetd.c     28 Jul 2006 09:29:47 -0000
@@ -227,6 +227,7 @@ void                set_proc_title __P ((char *, int))
 void           initring __P((void));
 long           machtime __P((void));
 void            run_service __P ((int ctrl, struct servtab *sep));
+void            prepenv __P ((int ctrl, struct sockaddr_in sa_client));
 
 struct biltin {
   const char   *bi_service;    /* internally provided service name */
@@ -354,7 +355,11 @@ usage (int err)
               __progname);
       puts ("Internet super-server.\n\n\
   -d, --debug               Debug mode\n\
+      --environment         Pass local and remote socket information in\n\
+                            environment variables\n\
   -R, --rate NUMBER         Maximum invocation rate (per second)\n\
+      --resolve             Resolve IP addresses when setting environment\n\
+                            variables (see --environment)\n\
       --help                Display this help and exit\n\
   -V, --version             Output version information and exit");
 
@@ -363,6 +368,9 @@ usage (int err)
   exit (err);
 }
 
+static int env_option;      /* Set environment variables */
+static int resolve_option;  /* Resolve IP addresses */
+
 static const char *short_options = "dR:V";
 static struct option long_options[] =
 {
@@ -370,6 +378,8 @@ static struct option long_options[] =
   { "rate", required_argument, 0, 'R' },
   { "help", no_argument, 0, '&' },
   { "version", no_argument, 0, 'V' },
+  { "resolve", no_argument, &resolve_option, 1 },
+  { "environment", no_argument, &env_option, 1 },
   { 0, 0, 0, 0 }
 };
 
@@ -425,6 +435,9 @@ main (int argc, char *argv[], char *envp
          exit (0);
          /* Not reached.  */
 
+       case 0:
+         break;
+         
        case '?':
        default:
          usage (1);
@@ -432,6 +445,9 @@ main (int argc, char *argv[], char *envp
        }
     }
 
+  if (resolve_option)
+    env_option = 1;
+  
   if (optind < argc)
     {
       int i;
@@ -514,7 +530,11 @@ main (int argc, char *argv[], char *envp
              fprintf (stderr, "someone wants %s\n", sep->se_service);
            if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
              {
-               ctrl = accept (sep->se_fd, NULL, NULL);
+               struct sockaddr_in sa_client;
+               socklen_t len = sizeof (sa_client);
+               
+               ctrl = accept (sep->se_fd, (struct sockaddr *)&sa_client,
+                              &len);
                if (debug)
                  fprintf (stderr, "accept, ctrl %d\n", ctrl);
                if (ctrl < 0)
@@ -524,6 +544,8 @@ main (int argc, char *argv[], char *envp
                              sep->se_service);
                    continue;
                  }
+               if (env_option)
+                 prepenv (ctrl, sa_client);
              }
            else
              ctrl = sep->se_fd;
@@ -821,14 +843,26 @@ nextconfig (const char *file)
          sep->se_fd = -1;
          continue;
        }
-#ifndef IPV6 /* This code is moved to setup() for IPV6.  */
+#ifndef IPV6 /* FIXME: This code is moved to setup() for IPV6, which is
+               wrong */
       sp = getservbyname (sep->se_service, sep->se_proto);
       if (sp == 0)
        {
-         syslog (LOG_ERR, "%s/%s: unknown service",
-                 sep->se_service, sep->se_proto);
-         sep->se_checked = 0;
-         continue;
+         static struct servent servent;
+         char *p;
+         unsigned long val;
+         unsigned short port;
+
+         val = strtoul (sep->se_service, &p, 0);
+         if (*p || (port = val) != val)
+           {
+             syslog (LOG_ERR, "%s/%s: unknown service",
+                     sep->se_service, sep->se_proto);
+             sep->se_checked = 0;
+             continue;
+           }
+         servent.s_port = htons (port);
+         sp = &servent;
        }
       if (sp->s_port != sep->se_ctrladdr.sin_port)
        {
@@ -1712,3 +1746,71 @@ tcpmux(int s, struct servtab *sep)
   strwrite (s, "-Service not available\r\n");
   exit (1);
 }
+
+/* Set TCP environment variables, modelled after djb's ucspi-tcp tools:
+   http://cr.yp.to/ucspi-tcp/environment.html
+   FIXME: This needs support for IPv6
+*/
+void
+prepenv (int ctrl, struct sockaddr_in sa_client)
+{
+  char str[16];
+  char *ip;
+  struct hostent *host;
+  struct sockaddr_in sa_server;
+  socklen_t len = sizeof (sa_server);
+
+  setenv ("PROTO", "TCP", 1);
+  unsetenv ("TCPLOCALIP");
+  unsetenv ("TCPLOCALHOST");
+  unsetenv ("TCPLOCALPORT");
+  unsetenv ("TCPREMOTEIP");
+  unsetenv ("TCPREMOTEPORT");
+  unsetenv ("TCPREMOTEHOST");
+  
+  if (getsockname (ctrl, (struct sockaddr*)&sa_server, &len) < 0)
+    syslog (LOG_WARNING, "getsockname(): %m");
+  else
+    {
+      ip = inet_ntoa (sa_server.sin_addr);
+      if (ip)
+       {
+         if (setenv ("TCPLOCALIP", ip, 1) < 0)
+           syslog (LOG_WARNING, "setenv (TCPLOCALIP): %m");
+       }
+
+      snprintf (str, sizeof (str), "%d", ntohs (sa_server.sin_port));
+      setenv ("TCPLOCALPORT", str, 1);
+
+      if (resolve_option)
+       {
+         if ((host = gethostbyaddr((char *) &sa_server.sin_addr,
+                                   sizeof (sa_server.sin_addr),
+                                   AF_INET)) == NULL)
+           syslog (LOG_WARNING, "gethostbyaddr: %m");
+         else if (setenv ("TCPLOCALHOST", host->h_name, 1) < 0)
+           syslog (LOG_WARNING, "setenv(TCPLOCALHOST): %m");
+       }
+    }
+
+  ip = inet_ntoa (sa_client.sin_addr);
+  if (ip)
+    {
+      if (setenv ("TCPREMOTEIP", ip, 1) < 0)
+       syslog (LOG_WARNING, "setenv(TCPREMOTEIP): %m");
+    }
+
+  snprintf (str, sizeof (str), "%d", ntohs (sa_client.sin_port));
+  if (setenv ("TCPREMOTEPORT", str, 1) < 0)
+    syslog (LOG_WARNING, "setenv(TCPREMOTEPORT): %m");
+
+  if (resolve_option)
+    {
+      if ((host = gethostbyaddr ((char *) &sa_client.sin_addr,
+                                sizeof (sa_client.sin_addr),
+                                AF_INET)) == NULL)
+       syslog (LOG_WARNING, "gethostbyaddr: %m");
+      else if (setenv ("TCPREMOTEHOST", host->h_name, 1) < 0)
+       syslog (LOG_WARNING, "setenv(TCPREMOTEHOST): %m");
+    }
+}