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[become] / src / name.c

/* -*-c-*-
 *
 * $Id: name.c,v 1.10 2004/04/08 01:36:20 mdw Exp $
 *
 * Looking up of names in symbol tables
 *
 * (c) 1998 EBI
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of `become'
 *
 * `Become' is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * `Become' 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with `become'; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

/* --- ANSI headers --- */

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* --- Unix headers --- */

#include <sys/types.h>
#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <netdb.h>
#include <grp.h>
#include <pwd.h>

/* --- mLib headers --- */

#include <mLib/alloc.h>
#include <mLib/sym.h>

/* --- Local headers --- */

#include "config.h"

#include "become.h"
#include "class.h"
#include "name.h"
#include "netg.h"
#include "userdb.h"

/*----- Static variables --------------------------------------------------*/

static sym_table name__table;           /* Symbol table for everything */

/*----- Main code ---------------------------------------------------------*/

/* --- @name__get@ --- *
 *
 * Arguments:   @const char *p@ = pointer to the name we want
 *              @unsigned type@ = type of class it should have
 *
 * Returns:     A pointer to a name ready to use, or zero if there's a type
 *              conflict.
 *
 * Use:         Creates a name of the appropriate type all ready to use.
 */

static name *name__get(const char *p, unsigned type)
{
  unsigned f;
  name *n = sym_find(&name__table, p, -1, sizeof(*n), &f);
  if (!f)
    n->c = 0;
  return ((n->c && !(n->c->type & type)) ? 0 : n);
}

/* --- @name__sanitise@ --- *
 *
 * Arguments:   @const char *n@ = pointer to a name
 *              @char *buf@ = pointer to a buffer of space
 *              @size_t sz@ = size of the buffer
 *
 * Returns:     A pointer to the transformed name in the buffer, or null
 *              if there wasn't enough space.
 *
 * Use:         Transforms a name so that it only contains nice characters.
 */

static char *name__sanitise(const char *n, char *buf, size_t sz)
{
  char *p = buf;

  if (strlen(n) + 1 > sz)
    return (0);

  while (*n) {
    if (isalnum((unsigned char)*n))
      *p++ = *n;
    else
      *p++ = '_';
    n++;
  }
  *p++ = 0;
  return (buf);
}

/* --- @name__users@ --- *
 *
 * Arguments:   ---
 *
 * Returns:     ---
 *
 * Use:         Adds all of the users registered with the user database to
 *              the name table.  Also adds the users' primary groups.
 */

static void name__users(void)
{
  struct passwd *pw;
  struct group *gr;
  char buf[32];

  userdb_iterateUsers();
  while ((pw = userdb_nextUser()) != 0) {
    name *n;
    uid_t u = pw->pw_uid;

    /* --- First, add the user to the table --- */

    if (name__sanitise(pw->pw_name, buf, sizeof(buf)) &&
        (n = name__get(buf, clType_user)) != 0)
      n->c = class_addUser(n->c, u);

    /* --- Now handle the user's default group --- */

    if ((gr = userdb_groupById(pw->pw_gid)) != 0 &&
        name__sanitise(gr->gr_name, buf, sizeof(buf)) &&
        (n = name__get(buf, clType_user)) != 0)
      n->c = class_addUser(n->c, u);
  }
}

/* --- @name__groups@ --- *
 *
 * Arguments:   ---
 *
 * Returns:     ---
 *
 * Use:         Adds users into all of their supplementary groups.
 */

static void name__groups(void)
{
  struct group *gr;
  struct passwd *pw;
  char **p;
  char buf[32];

  userdb_iterateGroups();
  while ((gr = userdb_nextGroup()) != 0) {
    name *n;

    if (name__sanitise(gr->gr_name, buf, sizeof(buf)) &&
        (n = name__get(buf, clType_user)) != 0) {

      /* --- Now add all of the members --- */

      for (p = gr->gr_mem; *p; p++) {
        if ((pw = userdb_userByName(*p)) != 0)
          n->c = class_addUser(n->c, pw->pw_uid);
      }
      if (!n->c)
        n->c = class_none;
    }
  }
}

/* --- @name__scan@ --- *
 *
 * Arguments:   @netg *n@ = the netgroup handle we're scanning
 *              @const char *host@ = the host name
 *              @const char *user@ = the user name
 *              @const char *domain@ = the (NIS?) domain name
 *              @void *ctx@ = some context pointer
 *
 * Returns:     Zero to continue scanning.
 *
 * Use:         Scans a netgroup, adding items to the name table.
 */

/* --- A data type --- */

typedef struct name__scanctx {
  char *name;                           /* Netgroup name prefixed with `?_'*/
  unsigned f;                           /* Various interesting flags */
  name *h;                              /* Name entry for hosts */
  name *u;                              /* Name entry for users */
} name__scanctx;

enum { f_host = 1, f_user = 2 };

/* --- And now for the real code --- */

static int name__scan(netg *n, const char *host, const char *user,
                      const char *domain, void *ctx)
{
  name__scanctx *sc = ctx;

  /* --- Add the host to the hosts class --- */

  if (sc->f & f_host && host) {
    struct hostent *h;
    struct in_addr in;
    const char *a;

    /* --- First ensure that I have a host class --- */

    if (!sc->h) {
      sc->name[0] = 'h';
      sc->h = name__get(sc->name, clType_host);
      if (!sc->h) {
        sc->f &= ~f_host;
        goto done_host;
      }
    }

    /* --- Now that I've done that, try to add the host --- *
     *
     * I'll turn it into an IP address.  There's less chance of confusion
     * that way.
     */

    if ((h = gethostbyname(host)) == 0)
      goto done_host;
    memcpy(&in, h->h_addr, sizeof(in));
    if ((a = inet_ntoa(in)) == 0)
      goto done_host;
    sc->h->c = class_addString(sc->h->c, a);
  done_host:;
  }

  /* --- Add the user to the users class --- */

  if (sc->f & f_user && user) {
    struct passwd *pw;
    
    /* --- First ensure that I have a user class --- */

    if (!sc->u) {
      sc->name[0] = 'u';
      sc->u = name__get(sc->name, clType_user);
      if (!sc->u) {
        sc->f &= ~f_user;
        goto done_user;
      }
    }

    /* --- Add the user to the list --- */

    if ((pw = userdb_userByName(user)) == 0)
      goto done_user;
    sc->u->c = class_addUser(sc->u->c, pw->pw_uid);
  done_user:;
  }

  return (0);
}

/* --- @name__netgroups@ --- *
 *
 * Arguments:   ---
 *
 * Returns:     ---
 *
 * Use:         Populates the name table with netgroup information.
 */

void name__netgroups(void)
{
  netg *n;
  char buf[32];
  const char *p;
  name__scanctx sc;

  netg_iterate();
  buf[1] = '_';
  while ((n = netg_next()) != 0) {
    p = netg_name(n);
    if (name__sanitise(p, buf + 2, sizeof(buf) - 2) == 0)
      continue;
    sc.name = buf;
    sc.u = sc.h = 0;
    sc.f = f_host | f_user;
    netg_scan(n, name__scan, &sc);
  }
}

/* --- @name_init@ --- *
 *
 * Arguments:   ---
 *
 * Returns:     ---
 *
 * Use:         Initialises the name table.  Requires the user database to
 *              be populated (see @userdb_local@ and @userdb_yp@, and
 *              @netg_init@).
 */

void name_init(void)
{
  /* --- Initialise the name table --- */

  sym_create(&name__table);

  /* --- Add everyone into the table --- */

  name__users();
  name__groups();
  name__netgroups();

  /* --- Finally add in the `all' and `none' classes --- *
   *
   * Do that now, to prevent them being overwritten by the above.
   */

  {
    name *n;
    unsigned f;

    n = sym_find(&name__table, "all", -1, sizeof(name), &f);
    if (f)
      class_dec(n->c);
    n->c = class_all;

    n = sym_find(&name__table, "none", -1, sizeof(name), &f);
    if (f)
      class_dec(n->c);
    n->c = class_none;
  }
}

/* --- @name_end@ --- *
 *
 * Arguments:   ---
 *
 * Returns:     ---
 *
 * Use:         Closes down the name database, so that it can be
 *              reinitialised.
 */

void name_end(void)
{
  /* --- Empty the symbol table --- */

  {
    sym_iter i;
    name *n;

    for (sym_mkiter(&i, &name__table); (n = sym_next(&i)) != 0; ) {
      if (n->c)
        class_dec(n->c);
    }
  }

  /* --- Destroy and recreate the table --- */

  sym_destroy(&name__table);
}

/* --- @name_find@ --- *
 *
 * Arguments:   @const char *p@ = pointer to name to look up
 *              @unsigned create@ = whether to create the item
 *              @unsigned *f@ = whether the item was created
 *
 * Returns:     Pointer to a @name@ block containing the symbol, or
 *              zero if it wasn't found and we didn't want to create a
 *              new one.
 *
 * Use:         Looks up a name in the symbol table and returns the
 *              item so located.
 */

name *name_find(const char *p, unsigned create, unsigned *f)
{
  /* --- This is a trivial veneer onto @sym_find@ --- */

  return (sym_find(&name__table, p, -1, create ? sizeof(name) : 0, f));
}

/* --- @name_dump@ --- *
 *
 * Arguments:   ---
 *
 * Returns:     ---
 *
 * Use:         Dumps a complete listing of the symbol table.
 */

void name_dump(void)
{
#ifdef TRACING
  sym_iter i;
  name *n;

  trace(TRACE_DEBUG, "name: dumping names");
  for (sym_mkiter(&i, &name__table); (n = sym_next(&i)) != 0; ) {
    trace(TRACE_DEBUG, "name: dumping `%s'", n->base.name);
    if (!n->c)
      trace(TRACE_DEBUG, "name:   <empty>");
    else
      class_dump(n->c, 1);
  }
#endif
}  

/*----- Test driver -------------------------------------------------------*/

#ifdef TEST_RIG

int main(void)
{
  ego("name-test");
  trace_on(stdout, TRACE_ALL);
  userdb_init();
  userdb_local();
  userdb_yp();
  netg_init();
  name_init();
  /* printf("loaded (%lu)\n", track_memused()); */
#ifdef notdef
  getchar();
  for (;;) {
    name_end();
    netg_end();
    userdb_end();
    /* printf("cleared (%lu)\n", track_memused()); */
    /* track_memlist(); */
    userdb_init();
    userdb_local();
    userdb_yp();
    netg_init();
    name_init();
    /* printf("reloaded (%lu)\n", track_memused()); */
    getchar();
  }
#else
  name_dump();
#endif
  return (0);
}

#endif