/* Copyright (c) 1998-2022 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

/* getent: get entries from administrative database.  */

#include <aliases.h>
#include <argp.h>
#include <ctype.h>
#include <error.h>
#include <grp.h>
#include <gshadow.h>
#include <libintl.h>
#include <locale.h>
#include <mcheck.h>
#include <netdb.h>
#include <pwd.h>
#include <shadow.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <netinet/ether.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <scratch_buffer.h>
#include <inttypes.h>

/* Get libc version number.  */
#include <version.h>

#define PACKAGE _libc_intl_domainname

/* Name and version of program.  */
static void print_version (FILE *stream, struct argp_state *state);
void (*argp_program_version_hook) (FILE *, struct argp_state *) = print_version;

/* Short description of parameters.  */
static const char args_doc[] = N_("database [key ...]");

/* Supported options. */
static const struct argp_option args_options[] =
  {
    { "service", 's', N_("CONFIG"), 0, N_("Service configuration to be used") },
    { "no-idn", 'i', NULL, 0, N_("disable IDN encoding") },
    { "no-addrconfig", 'A', NULL, 0,
      N_("do not filter out unsupported IPv4/IPv6 addresses (with ahosts*)") },
    { NULL, 0, NULL, 0, NULL },
  };

/* Short description of program.  */
static const char doc[] = N_("Get entries from administrative database.");

/* Prototype for option handler.  */
static error_t parse_option (int key, char *arg, struct argp_state *state);

/* Function to print some extra text in the help message.  */
static char *more_help (int key, const char *text, void *input);

/* Data structure to communicate with argp functions.  */
static struct argp argp =
  {
    args_options, parse_option, args_doc, doc, NULL, more_help
  };

/* Additional getaddrinfo flags for IDN encoding.  */
static int idn_flags = AI_IDN | AI_CANONIDN;

/* Set to 0 by --no-addrconfig.  */
static int addrconfig_flags = AI_ADDRCONFIG;

/* Print the version information.  */
static void
print_version (FILE *stream, struct argp_state *state)
{
  fprintf (stream, "getent %s%s\n", PKGVERSION, VERSION);
  fprintf (stream, gettext ("\
Copyright (C) %s Free Software Foundation, Inc.\n\
This is free software; see the source for copying conditions.  There is NO\n\
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
"), "2022");
  fprintf (stream, gettext ("Written by %s.\n"), "Thorsten Kukuk");
}

/* This is for aliases */
static void
print_aliases (struct aliasent *alias)
{
  unsigned int i = 0;

  printf ("%s: ", alias->alias_name);
  for  (i = strlen (alias->alias_name); i < 14; ++i)
    fputs_unlocked (" ", stdout);

  for (i = 0; i < alias->alias_members_len; ++i)
    printf ("%s%s",
	    alias->alias_members [i],
	    i + 1 == alias->alias_members_len ? "\n" : ", ");
}

static int
aliases_keys (int number, char *key[])
{
  int result = 0;
  int i;
  struct aliasent *alias;

  if (number == 0)
    {
      setaliasent ();
      while ((alias = getaliasent ()) != NULL)
	print_aliases (alias);
      endaliasent ();
      return result;
    }

  for (i = 0; i < number; ++i)
    {
      alias = getaliasbyname (key[i]);

      if (alias == NULL)
	result = 2;
      else
	print_aliases (alias);
    }

  return result;
}

/* This is for ethers */
static int
ethers_keys (int number, char *key[])
{
  int result = 0;
  int i;

  if (number == 0)
    {
      fprintf (stderr, _("Enumeration not supported on %s\n"), "ethers");
      return 3;
    }

  for (i = 0; i < number; ++i)
    {
      struct ether_addr *ethp, eth;
      char buffer [1024], *p;

      ethp = ether_aton (key[i]);
      if (ethp != NULL)
	{
	  if (ether_ntohost (buffer, ethp))
	    {
	      result = 2;
	      continue;
	    }
	  p = buffer;
	}
      else
	{
	  if (ether_hostton (key[i], &eth))
	    {
	      result = 2;
	      continue;
	    }
	  p = key[i];
	  ethp = &eth;
	}
      printf ("%s %s\n", ether_ntoa (ethp), p);
    }

  return result;
}

/* This is for group */
static void
print_group (struct group *grp)
{
  if (putgrent (grp, stdout) != 0)
    fprintf (stderr, "error writing group entry: %m\n");
}

static int
group_keys (int number, char *key[])
{
  int result = 0;
  int i;
  struct group *grp;

  if (number == 0)
    {
      setgrent ();
      while ((grp = getgrent ()) != NULL)
	print_group (grp);
      endgrent ();
      return result;
    }

  for (i = 0; i < number; ++i)
    {
      errno = 0;
      char *ep;
      gid_t arg_gid = strtoul(key[i], &ep, 10);

      if (errno != EINVAL && *key[i] != '\0' && *ep == '\0')
	/* Valid numeric gid.  */
	grp = getgrgid (arg_gid);
      else
	grp = getgrnam (key[i]);

      if (grp == NULL)
	result = 2;
      else
	print_group (grp);
    }

  return result;
}

/* This is for gshadow */
static void
print_gshadow (struct sgrp *sg)
{
  if (putsgent (sg, stdout) != 0)
    fprintf (stderr, "error writing gshadow entry: %m\n");
}

static int
gshadow_keys (int number, char *key[])
{
  int result = 0;
  int i;

  if (number == 0)
    {
      struct sgrp *sg;

      setsgent ();
      while ((sg = getsgent ()) != NULL)
	print_gshadow (sg);
      endsgent ();
      return result;
    }

  for (i = 0; i < number; ++i)
    {
      struct sgrp *sg;

      sg = getsgnam (key[i]);

      if (sg == NULL)
	result = 2;
      else
	print_gshadow (sg);
    }

  return result;
}

/* This is for hosts */
static void
print_hosts (struct hostent *host)
{
  unsigned int cnt;

  for (cnt = 0; host->h_addr_list[cnt] != NULL; ++cnt)
    {
      char buf[INET6_ADDRSTRLEN];
      const char *ip = inet_ntop (host->h_addrtype, host->h_addr_list[cnt],
				  buf, sizeof (buf));

      printf ("%-15s %s", ip, host->h_name);

      unsigned int i;
      for (i = 0; host->h_aliases[i] != NULL; ++i)
	{
	  putchar_unlocked (' ');
	  fputs_unlocked (host->h_aliases[i], stdout);
	}
      putchar_unlocked ('\n');
    }
}

static int
hosts_keys (int number, char *key[])
{
  int result = 0;
  int i;
  struct hostent *host;

  if (number == 0)
    {
      sethostent (0);
      while ((host = gethostent ()) != NULL)
	print_hosts (host);
      endhostent ();
      return result;
    }

  for (i = 0; i < number; ++i)
    {
      struct hostent *host = NULL;
      char addr[IN6ADDRSZ];

      if (inet_pton (AF_INET6, key[i], &addr) > 0)
	host = gethostbyaddr (addr, IN6ADDRSZ, AF_INET6);
      else if (inet_pton (AF_INET, key[i], &addr) > 0)
	host = gethostbyaddr (addr, INADDRSZ, AF_INET);
      else if ((host = gethostbyname2 (key[i], AF_INET6)) == NULL)
	host = gethostbyname2 (key[i], AF_INET);

      if (host == NULL)
	result = 2;
      else
	print_hosts (host);
    }

  return result;
}

/* This is for hosts, but using getaddrinfo */
static int
ahosts_keys_int (int af, int xflags, int number, char *key[])
{
  int result = 0;
  int i;
  struct hostent *host;

  if (number == 0)
    {
      sethostent (0);
      while ((host = gethostent ()) != NULL)
	print_hosts (host);
      endhostent ();
      return result;
    }

  struct addrinfo hint;
  memset (&hint, '\0', sizeof (hint));
  hint.ai_flags = (AI_V4MAPPED | addrconfig_flags | AI_CANONNAME
		   | idn_flags | xflags);
  hint.ai_family = af;

  for (i = 0; i < number; ++i)
    {
      struct addrinfo *res;

      if (getaddrinfo (key[i], NULL, &hint, &res) != 0)
	result = 2;
      else
	{
	  struct addrinfo *runp = res;

	  while (runp != NULL)
	    {
	      char sockbuf[20];
	      const char *sockstr;
	      if (runp->ai_socktype == SOCK_STREAM)
		sockstr = "STREAM";
	      else if (runp->ai_socktype == SOCK_DGRAM)
		sockstr = "DGRAM";
	      else if (runp->ai_socktype == SOCK_RAW)
		sockstr = "RAW";
#ifdef SOCK_SEQPACKET
	      else if (runp->ai_socktype == SOCK_SEQPACKET)
		sockstr = "SEQPACKET";
#endif
#ifdef SOCK_RDM
	      else if (runp->ai_socktype == SOCK_RDM)
		sockstr = "RDM";
#endif
#ifdef SOCK_DCCP
	      else if (runp->ai_socktype == SOCK_DCCP)
		sockstr = "DCCP";
#endif
#ifdef SOCK_PACKET
	      else if (runp->ai_socktype == SOCK_PACKET)
		sockstr = "PACKET";
#endif
	      else
		{
		  snprintf (sockbuf, sizeof (sockbuf), "%d",
			    runp->ai_socktype);
		  sockstr = sockbuf;
		}

	      /* Three digits per byte, plus '%' and null terminator.  */
	      char scope[3 * sizeof (uint32_t) + 2];
	      struct sockaddr_in6 *addr6
		= (struct sockaddr_in6 *) runp->ai_addr;
	      if (runp->ai_family != AF_INET6 || addr6->sin6_scope_id == 0)
		/* No scope ID present.  */
		scope[0] = '\0';
	      else
		snprintf (scope, sizeof (scope), "%%%" PRIu32,
			  addr6->sin6_scope_id);

	      char buf[INET6_ADDRSTRLEN];
	      if (inet_ntop (runp->ai_family,
			     runp->ai_family == AF_INET
			     ? (void *) &((struct sockaddr_in *) runp->ai_addr)->sin_addr
			     : &addr6->sin6_addr,
			     buf, sizeof (buf)) == NULL)
		{
		  strcpy (buf, "<invalid>");
		  scope[0] = '\0';
		}

	      int pad = 15 - strlen (buf) - strlen (scope);
	      if (pad < 0)
		pad = 0;

	      printf ("%s%-*s %-6s %s\n",
		      buf, pad, scope, sockstr, runp->ai_canonname ?: "");

	      runp = runp->ai_next;
	    }

	  freeaddrinfo (res);
	}
    }

  return result;
}

static int
ahosts_keys (int number, char *key[])
{
  return ahosts_keys_int (AF_UNSPEC, 0, number, key);
}

static int
ahostsv4_keys (int number, char *key[])
{
  return ahosts_keys_int (AF_INET, 0, number, key);
}

static int
ahostsv6_keys (int number, char *key[])
{
  return ahosts_keys_int (AF_INET6, AI_V4MAPPED, number, key);
}

/* This is for netgroup */
static int
netgroup_keys (int number, char *key[])
{
  int result = 0;

  if (number == 0)
    {
      fprintf (stderr, _("Enumeration not supported on %s\n"), "netgroup");
      return 3;
    }

  if (number == 4)
    {
      char *host = strcmp (key[1], "*") == 0 ? NULL : key[1];
      char *user = strcmp (key[2], "*") == 0 ? NULL : key[2];
      char *domain = strcmp (key[3], "*") == 0 ? NULL : key[3];

      printf ("%-21s (%s,%s,%s) = %d\n",
	      key[0], host ?: "", user ?: "", domain ?: "",
	      innetgr (key[0], host, user, domain));
    }
  else if (number == 1)
    {
      if (!setnetgrent (key[0]))
	result = 2;
      else
	{
	  char *p[3];

	  printf ("%-21s", key[0]);

	  while (getnetgrent (p, p + 1, p + 2))
	    printf (" (%s,%s,%s)", p[0] ?: " ", p[1] ?: "", p[2] ?: "");
	  putchar_unlocked ('\n');
	}
    }

  endnetgrent ();

  return result;
}

#define DYNARRAY_STRUCT gid_list
#define DYNARRAY_ELEMENT gid_t
#define DYNARRAY_PREFIX gid_list_
#define DYNARRAY_INITIAL_SIZE 10
#include <malloc/dynarray-skeleton.c>

/* This is for initgroups */
static int
initgroups_keys (int number, char *key[])
{
  if (number == 0)
    {
      fprintf (stderr, _("Enumeration not supported on %s\n"), "initgroups");
      return 3;
    }

  struct gid_list list;
  gid_list_init (&list);
  if (!gid_list_resize (&list, 10))
    {
      fprintf (stderr, _("Could not allocate group list: %m\n"));
      return 3;
    }

  for (int i = 0; i < number; ++i)
    {
      int no = gid_list_size (&list);
      int n;
      while ((n = getgrouplist (key[i], -1, gid_list_begin (&list), &no)) == -1
	     && no > gid_list_size (&list))
	{
	  if (!gid_list_resize (&list, no))
	    {
	      fprintf (stderr, _("Could not allocate group list: %m\n"));
	      return 3;
	    }
	}

      if (n == -1)
	{
	  gid_list_free (&list);
	  return 1;
	}

      const gid_t *grps = gid_list_begin (&list);
      printf ("%-21s", key[i]);
      for (int j = 0; j < n; ++j)
	if (grps[j] != -1)
	  printf (" %ld", (long int) grps[j]);
      putchar_unlocked ('\n');
    }

  gid_list_free (&list);

  return 0;
}

/* This is for networks */
static void
print_networks (struct netent *net)
{
  unsigned int i;
  struct in_addr ip;
  ip.s_addr = htonl (net->n_net);

  printf ("%-21s %s", net->n_name, inet_ntoa (ip));

  i = 0;
  while (net->n_aliases[i] != NULL)
    {
      putchar_unlocked (' ');
      fputs_unlocked (net->n_aliases[i], stdout);
      ++i;
    }
  putchar_unlocked ('\n');
}

static int
networks_keys (int number, char *key[])
{
  int result = 0;
  int i;
  struct netent *net;

  if (number == 0)
    {
      setnetent (0);
      while ((net = getnetent ()) != NULL)
	print_networks (net);
      endnetent ();
      return result;
    }

  for (i = 0; i < number; ++i)
    {
      if (isdigit (key[i][0]))
	net = getnetbyaddr (ntohl (inet_addr (key[i])), AF_UNSPEC);
      else
	net = getnetbyname (key[i]);

      if (net == NULL)
	result = 2;
      else
	print_networks (net);
    }

  return result;
}

/* Now is all for passwd */
static void
print_passwd (struct passwd *pwd)
{
  if (putpwent (pwd, stdout) != 0)
    fprintf (stderr, "error writing passwd entry: %m\n");
}

static int
passwd_keys (int number, char *key[])
{
  int result = 0;
  int i;
  struct passwd *pwd;

  if (number == 0)
    {
      setpwent ();
      while ((pwd = getpwent ()) != NULL)
	print_passwd (pwd);
      endpwent ();
      return result;
    }

  for (i = 0; i < number; ++i)
    {
      errno = 0;
      char *ep;
      uid_t arg_uid = strtoul(key[i], &ep, 10);

      if (errno != EINVAL && *key[i] != '\0' && *ep == '\0')
	/* Valid numeric uid.  */
	pwd = getpwuid (arg_uid);
      else
	pwd = getpwnam (key[i]);

      if (pwd == NULL)
	result = 2;
      else
	print_passwd (pwd);
    }

  return result;
}

/* This is for protocols */
static void
print_protocols (struct protoent *proto)
{
  unsigned int i;

  printf ("%-21s %d", proto->p_name, proto->p_proto);

  i = 0;
  while (proto->p_aliases[i] != NULL)
    {
      putchar_unlocked (' ');
      fputs_unlocked (proto->p_aliases[i], stdout);
      ++i;
    }
  putchar_unlocked ('\n');
}

static int
protocols_keys (int number, char *key[])
{
  int result = 0;
  int i;
  struct protoent *proto;

  if (number == 0)
    {
      setprotoent (0);
      while ((proto = getprotoent ()) != NULL)
	print_protocols (proto);
      endprotoent ();
      return result;
    }

  for (i = 0; i < number; ++i)
    {
      if (isdigit (key[i][0]))
	proto = getprotobynumber (atol (key[i]));
      else
	proto = getprotobyname (key[i]);

      if (proto == NULL)
	result = 2;
      else
	print_protocols (proto);
    }

  return result;
}

#if HAVE_SUNRPC
/* Now is all for rpc */
static void
print_rpc (struct rpcent *rpc)
{
  int i;

  printf ("%-15s %d%s",
	  rpc->r_name, rpc->r_number, rpc->r_aliases[0] ? " " : "");

  for (i = 0; rpc->r_aliases[i]; ++i)
    printf (" %s", rpc->r_aliases[i]);
  putchar_unlocked ('\n');
}

static int
rpc_keys (int number, char *key[])
{
  int result = 0;
  int i;
  struct rpcent *rpc;

  if (number == 0)
    {
      setrpcent (0);
      while ((rpc = getrpcent ()) != NULL)
	print_rpc (rpc);
      endrpcent ();
      return result;
    }

  for (i = 0; i < number; ++i)
    {
      if (isdigit (key[i][0]))
	rpc = getrpcbynumber (atol (key[i]));
      else
	rpc = getrpcbyname (key[i]);

      if (rpc == NULL)
	result = 2;
      else
	print_rpc (rpc);
    }

  return result;
}
#endif

/* for services */
static void
print_services (struct servent *serv)
{
  unsigned int i;

  printf ("%-21s %d/%s", serv->s_name, ntohs (serv->s_port), serv->s_proto);

  i = 0;
  while (serv->s_aliases[i] != NULL)
    {
      putchar_unlocked (' ');
      fputs_unlocked (serv->s_aliases[i], stdout);
      ++i;
    }
  putchar_unlocked ('\n');
}

static int
services_keys (int number, char *key[])
{
  int result = 0;
  int i;
  struct servent *serv;

  if (!number)
    {
      setservent (0);
      while ((serv = getservent ()) != NULL)
	print_services (serv);
      endservent ();
      return result;
    }

  for (i = 0; i < number; ++i)
    {
      struct servent *serv;
      char *proto = strchr (key[i], '/');

      if (proto != NULL)
	*proto++ = '\0';

      char *endptr;
      long port = strtol (key[i], &endptr, 10);

      if (isdigit (key[i][0]) && *endptr == '\0'
	  && 0 <= port && port <= 65535)
	serv = getservbyport (htons (port), proto);
      else
	serv = getservbyname (key[i], proto);

      if (serv == NULL)
	result = 2;
      else
	print_services (serv);
    }

  return result;
}

/* This is for shadow */
static void
print_shadow (struct spwd *sp)
{
  if (putspent (sp, stdout) != 0)
    fprintf (stderr, "error writing shadow entry: %m\n");
}

static int
shadow_keys (int number, char *key[])
{
  int result = 0;
  int i;

  if (number == 0)
    {
      struct spwd *sp;

      setspent ();
      while ((sp = getspent ()) != NULL)
	print_shadow (sp);
      endspent ();
      return result;
    }

  for (i = 0; i < number; ++i)
    {
      struct spwd *sp;

      sp = getspnam (key[i]);

      if (sp == NULL)
	result = 2;
      else
	print_shadow (sp);
    }

  return result;
}

struct
  {
    const char *name;
    int (*func) (int number, char *key[]);
  } databases[] =
  {
#define D(name) { #name, name ## _keys },
D(ahosts)
D(ahostsv4)
D(ahostsv6)
D(aliases)
D(ethers)
D(group)
D(gshadow)
D(hosts)
D(initgroups)
D(netgroup)
D(networks)
D(passwd)
D(protocols)
#if HAVE_SUNRPC
D(rpc)
#endif
D(services)
D(shadow)
#undef D
    { NULL, NULL }
  };

/* Handle arguments found by argp. */
static error_t
parse_option (int key, char *arg, struct argp_state *state)
{
  char *endp;
  switch (key)
    {
    case 's':
      endp = strchr (arg, ':');
      if (endp == NULL)
	/* No specific database, change them all.  */
	for (int i = 0; databases[i].name != NULL; ++i)
	  __nss_configure_lookup (databases[i].name, arg);
      else
	{
	  int i;
	  for (i = 0; databases[i].name != NULL; ++i)
	    if (strncmp (databases[i].name, arg, endp - arg) == 0)
	      {
		__nss_configure_lookup (databases[i].name, endp + 1);
		break;
	      }
	  if (databases[i].name == NULL)
	    error (EXIT_FAILURE, 0, gettext ("Unknown database name"));
	}
      break;

    case 'i':
      idn_flags = 0;
      break;

    case 'A':
      addrconfig_flags = 0;
      break;

    default:
      return ARGP_ERR_UNKNOWN;
    }

  return 0;
}


static char *
more_help (int key, const char *text, void *input)
{
  switch (key)
    {
      size_t len;
      char *doc;
      FILE *fp;

    case ARGP_KEY_HELP_EXTRA:
      /* We print some extra information.  */
      fp = open_memstream (&doc, &len);
      if (fp != NULL)
	{
	  fputs_unlocked (_("Supported databases:\n"), fp);

	  for (int i = 0, col = 0; databases[i].name != NULL; ++i)
	    {
	      len = strlen (databases[i].name);
	      if (i != 0)
		{
		  if (col + len > 72)
		    {
		      col = 0;
		      fputc_unlocked ('\n', fp);
		    }
		  else
		    fputc_unlocked (' ', fp);
		}

	      fputs_unlocked (databases[i].name, fp);
	      col += len + 1;
	    }

	  fputs ("\n\n", fp);

	  fprintf (fp, gettext ("\
For bug reporting instructions, please see:\n\
%s.\n"), REPORT_BUGS_TO);

	  if (fclose (fp) == 0)
	    return doc;
	}
      break;

    default:
      break;
    }
  return (char *) text;
}


/* the main function */
int
main (int argc, char *argv[])
{
  /* Debugging support.  */
  mtrace ();

  /* Set locale via LC_ALL.  */
  setlocale (LC_ALL, "");
  /* Set the text message domain.  */
  textdomain (PACKAGE);

  /* Parse and process arguments.  */
  int remaining;
  argp_parse (&argp, argc, argv, 0, &remaining, NULL);

  if ((argc - remaining) < 1)
    {
      error (0, 0, gettext ("wrong number of arguments"));
      argp_help (&argp, stdout, ARGP_HELP_SEE, program_invocation_short_name);
      return 1;
    }

  for (int i = 0; databases[i].name; ++i)
    if (argv[remaining][0] == databases[i].name[0]
	&& !strcmp (argv[remaining], databases[i].name))
      return databases[i].func (argc - remaining - 1, &argv[remaining + 1]);

  fprintf (stderr, _("Unknown database: %s\n"), argv[remaining]);
  argp_help (&argp, stdout, ARGP_HELP_SEE, program_invocation_short_name);
  return 1;
}
