nss_gns_query.c File Reference

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "nss_gns_query.h"
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>

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Macros
#define	TIMEOUT   "5s"

Functions
static void	kwait (pid_t chld)
int	gns_resolve_name (int af, const char *name, struct userdata *u)
	Wrapper function that uses gnunet-gns cli tool to resolve an IPv4/6 address. More...

Macro Definition Documentation

TIMEOUT

#define TIMEOUT   "5s"

Definition at line 33 of file nss_gns_query.c.

Function Documentation

kwait()

static void kwait ( pid_t  chld )

static

Definition at line 36 of file nss_gns_query.c.

{
  int ret;
 
  kill (chld, SIGKILL);
  waitpid (chld, &ret, 0);
}

References ret.

Referenced by gns_resolve_name().

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gns_resolve_name()

int gns_resolve_name	(	int	af,
		const char *	name,
		struct userdata *	u
	)

Wrapper function that uses gnunet-gns cli tool to resolve an IPv4/6 address.

Parameters

af	address family
name	the name to resolve
u	the userdata (result struct)

Returns

-1 on internal error, -2 if request is not for GNS, -3 on timeout, else 0

Definition at line 58 of file nss_gns_query.c.

{
  FILE *p;
  char line[128];
  int ret;
  int retry = 0;
  int out[2];
  pid_t pid;
 
  if (0 == getuid ())
    return -2; /* GNS via NSS is NEVER for root */
 
query_gns:
  if (0 != pipe (out))
    return -1;
  pid = fork ();
  if (-1 == pid)
    return -1;
  if (0 == pid)
  {
    char *argv[] = { "gnunet-gns",
                     "-r", /* Raw output for easier parsing */
                     "-d", /* DNS compatibility (allow IDNA names, no UTF-8) */
                     "-t",
                     (AF_INET6 == af) ? "AAAA" : "A",
                     "-u",
                     (char *) name,
                     "-T",
                     TIMEOUT,
                     NULL };
 
    (void) close (STDOUT_FILENO);
    if ((0 != close (out[0])) ||
        (STDOUT_FILENO != dup2 (out[1], STDOUT_FILENO)))
      _exit (1);
    (void) execvp ("gnunet-gns", argv);
    _exit (1);
  }
  (void) close (out[1]);
  p = fdopen (out[0], "r");
  if (NULL == p)
  {
    kwait (pid);
    return -1;
  }
  while (NULL != fgets (line, sizeof(line), p))
  {
    if (u->count >= MAX_ENTRIES)
      break;
    if (line[strlen (line) - 1] == '\n')
    {
      line[strlen (line) - 1] = '\0';
      if (AF_INET == af)
      {
        if (inet_pton (af, line, &u->data.ipv4[u->count]))
        {
          u->count++;
          u->data_len += sizeof(ipv4_address_t);
        }
        else
        {
          (void) fclose (p);
          kwait (pid);
          errno = EINVAL;
          return -1;
        }
      }
      else if (AF_INET6 == af)
      {
        if (inet_pton (af, line, &u->data.ipv6[u->count]))
        {
          u->count++;
          u->data_len += sizeof(ipv6_address_t);
        }
        else
        {
          (void) fclose (p);
          kwait (pid);
          errno = EINVAL;
          return -1;
        }
      }
    }
  }
  (void) fclose (p);
  waitpid (pid, &ret, 0);
  if (! WIFEXITED (ret))
    return -1;
  if (4 == WEXITSTATUS (ret))
    return -2; /* not for GNS */
  if (5 == WEXITSTATUS (ret))
  {
    if (1 == retry)
      return -2; /* no go -> service unavailable */
    retry = 1;
    system ("gnunet-arm -s");
    goto query_gns; /* Try again */
  }
  if (3 == WEXITSTATUS (ret))
    return -2; /* timeout -> service unavailable */
  if ((2 == WEXITSTATUS (ret)) || (1 == WEXITSTATUS (ret)))
    return -2; /* launch failure -> service unavailable */
  return 0;
}

References userdata::count, userdata::data, userdata::data_len, userdata::ipv4, userdata::ipv6, kwait(), line, MAX_ENTRIES, name, p, pid, ret, and TIMEOUT.

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