Table for driving key data extraction.

[u/mdw/catacomb] / key-io.c

/* -*-c-*-
 *
 * $Id: key-io.c,v 1.2 2000/02/12 18:21:02 mdw Exp $
 *
 * Adding new keys to a key file
 *
 * (c) 1999 Straylight/Edgeware
 */

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

/*----- Revision history --------------------------------------------------* 
 *
 * $Log: key-io.c,v $
 * Revision 1.2  2000/02/12 18:21:02  mdw
 * Overhaul of key management (again).
 *
 * Revision 1.1  1999/12/22 15:47:48  mdw
 * Major key-management revision.
 *
 */

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

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

#include <mLib/bits.h>
#include <mLib/crc32.h>
#include <mLib/dstr.h>
#include <mLib/hash.h>
#include <mLib/str.h>
#include <mLib/sub.h>
#include <mLib/sym.h>
#include <mLib/url.h>

#include "key.h"

/*----- Tweakable macros --------------------------------------------------*/

#define KEY_LOAD(n) ((n) * 2)

/*----- Low-level functions -----------------------------------------------*/

/* --- @insert@ --- *
 *
 * Arguments:	@key_file *f@ = pointer to file structure
 *		@key *k@ = pointer to key block to insert
 *
 * Returns:	Error code (one of the @KERR@ code).
 *
 * Use:		Links a new key block into the complicated data structure
 *		which is a keyring file.
 */

static int insert(key_file *f, key *k)
{
  key_ref *kr = 0;
  unsigned found;

  /* --- Sanity preservatives --- */

  if (key_chkident(k->type))
    return (KERR_BADTYPE);
  else if (k->tag && key_chkident(k->tag))
    return (KERR_BADTAG);

  /* --- Insert into the tag table --- */

  if (k->tag) {
    kr = sym_find(&f->bytag, k->tag, -1, sizeof(*kr), &found);
    if (found)
      return (KERR_DUPTAG);
    kr->k = k;
  }

  /* --- Insert into the id table --- */

  {
    hash_base **bin, *b;

    bin = HASH_BIN(&f->byid, k->id);
    for (b = *bin; b; b = b->next) {
      if (b->hash == k->id) {
	if (kr)
	  sym_remove(&f->bytag, kr);
	return (KERR_DUPID);
      }
    }

    k->_b.next = *bin;
    *bin = &k->_b;
    k->_b.hash = k->id;
  }

  /* --- Extend the table --- */

  if (f->idload > 0)
    f->idload--;
  else if (hash_extend(&f->byid))
    f->idload = KEY_LOAD(f->byid.mask / 2);

  /* --- Insert into the type table --- */

  kr = sym_find(&f->bytype, k->type, -1, sizeof(*kr), &found);
  if (!found) {
    kr->k = k;
    k->next = 0;
  } else {
    key **p = &kr->k;
    if (k->exp != KEXP_FOREVER) {
      while (*p && (*p)->exp != KEXP_EXPIRE && (*p)->exp > k->exp)
	p = &(*p)->next;
    }
    k->next = *p;
    *p = k;
  }

  return (KERR_OK);
}

/*----- Reading and writing keys ------------------------------------------*/

/* --- @exptime@ --- *
 *
 * Arguments:	@const char *p@ = pointer to string
 *
 * Returns:	Time value.
 *
 * Use:		Translates an expiry or deletion time.
 */

time_t exptime(const char *p)
{
  size_t sz = strlen(p);
  if (strncmp(p, "expired", sz) == 0)
    return (KEXP_EXPIRE);
  else if (strncmp(p, "forever", sz) == 0)
    return (KEXP_FOREVER);
  else
    return (atol(p));
}

/* --- @key_merge@ --- *
 *
 * Arguments:	@key_file *f@ = pointer to file structure
 *		@const char *file@ = name of file (for error messages)
 *		@FILE *fp@ = file handle to read from
 *		@key_reporter *rep@ = error reporting function
 *		@void *arg@ = argument for function
 *
 * Returns:	Error code (one of the @KERR@ constants).
 *
 * Use:		Reads keys from a file, and inserts them into the file.
 */

int key_merge(key_file *f, const char *file, FILE *fp,
	      key_reporter *rep, void *arg)
{
  int line = 0;
  dstr l = DSTR_INIT;
  dstr n = DSTR_INIT, v = DSTR_INIT;

  if (!(f->f & KF_WRITE))
    return (KERR_READONLY);

  for (; dstr_putline(&l, fp) != EOF; DRESET(&l)) {
    char *vf[6];
    char *p = l.buf;
    key *k;

    /* --- Skip blank lines and comments --- *
     *
     * Quite what they're doing in what ought to be an automatically-
     * maintained file I don't know.
     */

    line++;
    while (isspace((unsigned char)*p))
      p++;
    if (!*p || *p == '#')
      continue;

    /* --- Break the line into fields --- *
     *
     * There are currently six fields of interest:
     *
     *   * The key's identification (id, tag and type).
     *   * The actual key data itself.
     *   * The key expiry time.
     *   * The key deletion time.
     *   * The attributes field.
     *   * Any further comments.
     *
     * All but the last field can contain no spaces.
     */

    {
      int n = str_split(p, vf, 5, &vf[5]);
      if (n < 4) {
	if (rep)
	  rep(file, line, "too few fields", arg);
	goto skip_0;
      }
    }

    /* --- Allocate a new key block --- */

    k = CREATE(key);

    /* --- Extract the key data into the block --- */

    if (key_read(vf[1], &k->k, 0)) {
      if (rep)
	rep(file, line, "bad key data", arg);
      goto skip_1;
    }

    /* --- Decode the identification field --- *
     *
     * For compatibility, derive a keyid from the key data.  This can only be
     * done if the key encoding is binary (and presumably old-encoding binary
     * at that).
     */

    {
      char *q = strchr(vf[0], ':');
      char *qq;

      if (!q) {
	if (k->k.e != KENC_BINARY) {
	  if (rep)
	    rep(file, line, "new-style key encoding but no keyid", arg);
	  goto skip_2;
	}
	k->id = crc32(0, k->k.u.k.k, k->k.u.k.sz);
	k->type = xstrdup(vf[0]);
	k->tag = 0;
      } else {
	*q++ = 0;
	k->id = strtoul(p, 0, 16);
	if ((qq = strchr(q, ':')) == 0 || !qq[1]) {
	  if (qq)
	    *qq = 0;
	  k->tag = 0;
	} else {
	  *qq++ = 0;
	  k->tag = xstrdup(qq);
	}
	k->type = xstrdup(q);
      }
    }

    /* --- Get a key block for the new key --- */

    k->exp = exptime(vf[2]);
    k->del = exptime(vf[3]);

    /* --- Insert the key block into the table --- */

    {
      int err;

    again:
      if ((err = insert(f, k)) < 0) {
	if (err == KERR_DUPTAG) {
	  if (rep)
	    rep(file, line, "duplicate key tag stripped", arg);
	  free(k->tag);
	  k->tag = 0;
	  goto again;
	}
	if (rep)
	  rep(file, line, key_strerror(err), arg);
	goto skip_3;
      }
    }
 
    /* --- Parse up the attributes, if specified --- */

    sym_create(&k->a);
    if (vf[4] && strcmp(vf[4], "-") != 0) {
      url_dctx uc;
      for (url_initdec(&uc, vf[4]); url_dec(&uc, &n, &v); ) {
	key_putattr(f, k, n.buf, v.buf);
	DRESET(&n); DRESET(&v);
      }
    }

    /* --- Insert the comment --- */

    if (vf[5])
      k->c = xstrdup(vf[5]);
    else
      k->c = 0;
    continue;

    /* --- Tidy up after something going wrong --- */

  skip_3:
    if (k->tag)
      free(k->tag);
    free(k->type);
  skip_2:
    key_destroy(&k->k);
  skip_1:
    DESTROY(k);
  skip_0:;
  }

  /* --- Extensive tidying up now required --- */

  dstr_destroy(&l);
  dstr_destroy(&n);
  dstr_destroy(&v);
  f->f |= KF_MODIFIED;
  return (0);
}

/* --- @key_extract@ --- *
 *
 * Arguments:	@key_file *f@ = pointer to file structure
 *		@key *k@ = key to extract
 *		@FILE *fp@ = file to write on
 *		@const key_filter *kf@ = pointer to key selection block
 *
 * Returns:	Zero if OK, EOF on error.
 *
 * Use:		Extracts a key to an ouptut file.
 */

int key_extract(key_file *f, key *k, FILE *fp, const key_filter *kf)
{
  dstr d = DSTR_INIT;
  time_t t = time(0);

  /* --- Skip the key if it's deleted or unselected--- */

  if (KEY_EXPIRED(t, k->del) || !key_match(&k->k, kf))
    return (0);

  /* --- Encode the key and write the easy stuff --- */

  key_fulltag(k, &d);
  DPUTC(&d, ' ');
  key_write(&k->k, &d, kf);
  DPUTC(&d, ' ');
  dstr_write(&d, fp);
  DRESET(&d);

  /* --- Write out the expiry and deletion times --- */

  if (KEY_EXPIRED(t, k->exp))
    fputs("expired ", fp);
  else if (k->exp == KEXP_FOREVER)
    fputs("forever ", fp);
  else
    fprintf(fp, "%li ", (long)k->exp);

  if (k->del == KEXP_FOREVER)
    fputs("forever ", fp);
  else
    fprintf(fp, "%li ", (long)k->del);

  /* --- Output the attributes --- */

  {
    int none = 1;
    sym_iter i;
    key_attr *a;
    url_ectx uc;

    url_initenc(&uc);
    for (sym_mkiter(&i, &k->a); (a = sym_next(&i)) != 0; ) {
      none = 0;
      url_enc(&uc, &d, SYM_NAME(a), a->p);
    }
    if (none)
      DPUTS(&d, "-");
    DWRITE(&d, fp);
  }

  dstr_destroy(&d);
  if (k->c) {
    putc(' ', fp);
    fputs(k->c, fp);
  }
  putc('\n', fp);
  return (ferror(fp) ? EOF : 0);
}

/*----- Opening and closing files -----------------------------------------*/

/* --- @key_open@ --- *
 *
 * Arguments:	@key_file *f@ = pointer to file structure to initialize
 *		@const char *file@ = pointer to the file name
 *		@int how@ = opening options (@KOPEN_*@).
 *		@key_reporter *rep@ = error reporting function
 *		@void *arg@ = argument for function
 *
 * Returns:	Zero if it worked, nonzero otherwise.
 *
 * Use:		Opens a key file, reads its contents, and stores them in a
 *		structure.  The file is locked appropriately until closed
 *		using @key_close@.  On an error, everything is cleared away
 *		tidily.  If the file is opened with @KOPEN_WRITE@, it's
 *		created if necessary, with read and write permissions for its
 *		owner only.
 */

int key_open(key_file *f, const char *file, int how,
	     key_reporter *rep, void *arg)
{
  if (key_lockfile(f, file, how))
    return (-1);

  /* --- Trivial bits of initialization --- */

  f->f = 0;
  f->name = xstrdup(file);

  /* --- Read the file of keys into the table --- */

  hash_create(&f->byid, 16);
  f->idload = KEY_LOAD(16);
  sym_create(&f->bytype);
  sym_create(&f->bytag);
  f->f |= KF_WRITE;
  key_merge(f, file, f->fp, rep, arg);
  if (how == KOPEN_READ)
    f->f &= ~(KF_WRITE | KF_MODIFIED);
  else
    f->f &= ~KF_MODIFIED;

  /* --- Close the file if only needed for reading --- */

  if (how == KOPEN_READ) {
    fclose(f->fp);
    f->fp = 0;
  }

  return (0);
}

/* --- @key_close@ --- *
 *
 * Arguments:	@key_file *f@ = pointer to key file block
 *
 * Returns:	A @KWRITE_@ code indicating how it went.
 *
 * Use:		Frees all the key data, writes any changes.  Make sure that
 *		all hell breaks loose if this returns @KWRITE_BROKEN@.
 */

int key_close(key_file *f)
{
  int e;
  hash_base *b;
  hash_iter i;

  if ((e = key_save(f)) != KWRITE_OK)
    return (e);

  /* --- Free all the individual keys --- */

  for (hash_mkiter(&i, &f->byid); (b = hash_next(&i)) != 0; ) {
    sym_iter j;
    key_attr *a;
    key *k = (key *)b;

    key_destroy(&k->k);
    free(k->type);
    free(k->tag);
    if (k->c)
      free(k->c);
    for (sym_mkiter(&j, &k->a); (a = sym_next(&j)) != 0; )
      free(a->p);
    sym_destroy(&k->a);
    DESTROY(k);
  }
  hash_destroy(&f->byid);
  sym_destroy(&f->bytype);
  sym_destroy(&f->bytag);

  if (f->fp)
    fclose(f->fp);
  free(f->name);
  return (KWRITE_OK);
}

/* --- @key_new@ ---
 *
 * Arguments:	@key_file *f@ = pointer to key file
 *		@uint32 id@ = keyid to set
 *		@const char *type@ = the type of this key
 *		@time_t exp@ = when the key expires
 *		@int *err@ = where to store the error condition
 *
 * Returns:	Key block containing new data, or null if it couldn't be
 *		done.
 *
 * Use:		Attaches a new key to a key file.  You must have a writable
 *		key file for this to work.
 *
 *		The type is a key type string.  This interface doesn't care
 *		about how type strings are formatted: it just treats them as
 *		opaque gobs of text.  Clients are advised to choose some
 *		standard for representing key types, though.
 *
 *		The expiry time should either be a time in the future, or the
 *		magic value @KEXP_FOREVER@ which means `never expire this
 *		key'.  Be careful with `forever' keys.  If I were you, I'd
 *		use a more sophisticated key management system than this for
 *		them.
 *
 *		You have to set the actual key yourself.
 */

key *key_new(key_file *f, uint32 id, const char *type, time_t exp, int *err)
{
  key *k = 0;
  time_t t = time(0);
  int e = KERR_OK;

  /* --- Make sure the file is writable --- */

  if (!(f->f & KF_WRITE))
    e = KERR_READONLY;
  else if (KEY_EXPIRED(t, exp))
    e = KERR_EXPIRED;
  else if (key_chkident(type))
    e = KERR_BADTYPE;
  else {
    k = CREATE(key);
    k->id = id;
    k->tag = 0;
    k->type = xstrdup(type);
    k->exp = k->del = exp;
    k->c = 0;
    k->k.e = 0;
    sym_create(&k->a);
    if ((e = insert(f, k)) == 0)
      f->f |= KF_MODIFIED;
    else {
      free(k->type);
      DESTROY(k);
      k = 0;
    }
  }
  return (k);
}

/*----- That's all, folks -------------------------------------------------*/