gnupg/g10/misc.c

/* misc.c - miscellaneous functions
 * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004,
 *               2005, 2006 Free Software Foundation, Inc.
 *
 * This file is part of GnuPG.
 *
 * GnuPG 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.
 *
 * GnuPG 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 * USA.
 */

#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#if defined(__linux__) && defined(__alpha__) && __GLIBC__ < 2
#include <asm/sysinfo.h>
#include <asm/unistd.h>
#endif
#ifdef HAVE_SETRLIMIT
#include <time.h>
#include <sys/time.h>
#include <sys/resource.h>
#endif
#ifdef ENABLE_SELINUX_HACKS
#include <sys/stat.h>
#endif

#ifdef HAVE_W32_SYSTEM
#include <time.h>
#include <process.h>
#include <windows.h> 
#include <shlobj.h>
#ifndef CSIDL_APPDATA
#define CSIDL_APPDATA 0x001a
#endif
#ifndef CSIDL_LOCAL_APPDATA
#define CSIDL_LOCAL_APPDATA 0x001c
#endif
#ifndef CSIDL_FLAG_CREATE
#define CSIDL_FLAG_CREATE 0x8000
#endif
#endif /*HAVE_W32_SYSTEM*/

#include "gpg.h"
#ifdef HAVE_W32_SYSTEM
# include "errors.h"
# include "dynload.h"
#endif /*HAVE_W32_SYSTEM*/
#include "util.h"
#include "main.h"
#include "photoid.h"
#include "options.h"
#include "call-agent.h"
#include "i18n.h"


static int
string_count_chr (const char *string, int c)
{
  int count;

  for (count=0; *string; string++ )
    if ( *string == c )
      count++;
  return count;
}



#ifdef ENABLE_SELINUX_HACKS
/* A object and a global variable to keep track of files marked as
   secured. */
struct secured_file_item 
{
  struct secured_file_item *next;
  ino_t ino;
  dev_t dev;
};
static struct secured_file_item *secured_files;
#endif /*ENABLE_SELINUX_HACKS*/



#if defined(__linux__) && defined(__alpha__) && __GLIBC__ < 2
static int
setsysinfo(unsigned long op, void *buffer, unsigned long size,
		     int *start, void *arg, unsigned long flag)
{
    return syscall(__NR_osf_setsysinfo, op, buffer, size, start, arg, flag);
}

void
trap_unaligned(void)
{
    unsigned int buf[2];

    buf[0] = SSIN_UACPROC;
    buf[1] = UAC_SIGBUS | UAC_NOPRINT;
    setsysinfo(SSI_NVPAIRS, buf, 1, 0, 0, 0);
}
#else
void
trap_unaligned(void)
{  /* dummy */
}
#endif


int
disable_core_dumps()
{
#ifdef HAVE_DOSISH_SYSTEM
    return 0;
#else
#ifdef HAVE_SETRLIMIT
    struct rlimit limit;

    limit.rlim_cur = 0;
    limit.rlim_max = 0;
    if( !setrlimit( RLIMIT_CORE, &limit ) )
	return 0;
    if( errno != EINVAL && errno != ENOSYS )
	log_fatal(_("can't disable core dumps: %s\n"), strerror(errno) );
#endif
    return 1;
#endif
}


/* For the sake of SELinux we want to restrict access through gpg to
   certain files we keep under our own control.  This function
   registers such a file and is_secured_file may then be used to
   check whether a file has ben registered as secured. */
void
register_secured_file (const char *fname)
{
#ifdef ENABLE_SELINUX_HACKS
  struct stat buf;
  struct secured_file_item *sf;

  /* Note that we stop immediatley if something goes wrong here. */
  if (stat (fname, &buf))
    log_fatal (_("fstat of `%s' failed in %s: %s\n"), fname, 
               "register_secured_file", strerror (errno));
/*   log_debug ("registering `%s' i=%lu.%lu\n", fname, */
/*              (unsigned long)buf.st_dev, (unsigned long)buf.st_ino); */
  for (sf=secured_files; sf; sf = sf->next)
    {
      if (sf->ino == buf.st_ino && sf->dev == buf.st_dev)
        return; /* Already registered.  */
    }

  sf = xmalloc (sizeof *sf);
  sf->ino = buf.st_ino;
  sf->dev = buf.st_dev;
  sf->next = secured_files;
  secured_files = sf;
#endif /*ENABLE_SELINUX_HACKS*/
}

/* Remove a file registered as secure. */
void
unregister_secured_file (const char *fname)
{
#ifdef ENABLE_SELINUX_HACKS
  struct stat buf;
  struct secured_file_item *sf, *sfprev;

  if (stat (fname, &buf))
    {
      log_error (_("fstat of `%s' failed in %s: %s\n"), fname,
                 "unregister_secured_file", strerror (errno));
      return;
    }
/*   log_debug ("unregistering `%s' i=%lu.%lu\n", fname,  */
/*              (unsigned long)buf.st_dev, (unsigned long)buf.st_ino); */
  for (sfprev=NULL,sf=secured_files; sf; sfprev=sf, sf = sf->next)
    {
      if (sf->ino == buf.st_ino && sf->dev == buf.st_dev)
        {
          if (sfprev)
            sfprev->next = sf->next;
          else
            secured_files = sf->next;
          xfree (sf);
          return;
        }
    }
#endif /*ENABLE_SELINUX_HACKS*/
}

/* Return true if FD is corresponds to a secured file.  Using -1 for
   FS is allowed and will return false. */ 
int 
is_secured_file (int fd)
{
#ifdef ENABLE_SELINUX_HACKS
  struct stat buf;
  struct secured_file_item *sf;

  if (fd == -1)
    return 0; /* No file descriptor so it can't be secured either.  */

  /* Note that we print out a error here and claim that a file is
     secure if something went wrong. */
  if (fstat (fd, &buf))
    {
      log_error (_("fstat(%d) failed in %s: %s\n"), fd, 
                 "is_secured_file", strerror (errno));
      return 1;
    }
/*   log_debug ("is_secured_file (%d) i=%lu.%lu\n", fd, */
/*              (unsigned long)buf.st_dev, (unsigned long)buf.st_ino); */
  for (sf=secured_files; sf; sf = sf->next)
    {
      if (sf->ino == buf.st_ino && sf->dev == buf.st_dev)
        return 1; /* Yes.  */
    }
#endif /*ENABLE_SELINUX_HACKS*/
  return 0; /* No. */
}

/* Return true if FNAME is corresponds to a secured file.  Using NULL,
   "" or "-" for FS is allowed and will return false. This function is
   used before creating a file, thus it won't fail if the file does
   not exist. */ 
int 
is_secured_filename (const char *fname)
{
#ifdef ENABLE_SELINUX_HACKS
  struct stat buf;
  struct secured_file_item *sf;

  if (iobuf_is_pipe_filename (fname) || !*fname)
    return 0; 

  /* Note that we print out a error here and claim that a file is
     secure if something went wrong. */
  if (stat (fname, &buf))
    {
      if (errno == ENOENT || errno == EPERM || errno == EACCES)
        return 0;
      log_error (_("fstat of `%s' failed in %s: %s\n"), fname,
                 "is_secured_filename", strerror (errno));
      return 1;
    }
/*   log_debug ("is_secured_filename (%s) i=%lu.%lu\n", fname, */
/*              (unsigned long)buf.st_dev, (unsigned long)buf.st_ino); */
  for (sf=secured_files; sf; sf = sf->next)
    {
      if (sf->ino == buf.st_ino && sf->dev == buf.st_dev)
        return 1; /* Yes.  */
    }
#endif /*ENABLE_SELINUX_HACKS*/
  return 0; /* No. */
}



u16
checksum_u16( unsigned n )
{
    u16 a;

    a  = (n >> 8) & 0xff;
    a += n & 0xff;
    return a;
}


u16
checksum( byte *p, unsigned n )
{
    u16 a;

    for(a=0; n; n-- )
	a += *p++;
    return a;
}

u16
checksum_mpi (gcry_mpi_t a)
{
  u16 csum;
  byte *buffer;
  size_t nbytes;

  if ( gcry_mpi_print (GCRYMPI_FMT_PGP, NULL, 0, &nbytes, a) )
    BUG ();
  /* Fixme: For numbers not in secure memory we should use a stack
   * based buffer and only allocate a larger one if mpi_print returns
   * an error. */
  buffer = (gcry_is_secure(a)?
            gcry_xmalloc_secure (nbytes) : gcry_xmalloc (nbytes));
  if ( gcry_mpi_print (GCRYMPI_FMT_PGP, buffer, nbytes, NULL, a) )
    BUG ();
  csum = checksum (buffer, nbytes);
  xfree (buffer);
  return csum;
}

u32
buffer_to_u32( const byte *buffer )
{
    unsigned long a;
    a =  *buffer << 24;
    a |= buffer[1] << 16;
    a |= buffer[2] << 8;
    a |= buffer[3];
    return a;
}

void
print_pubkey_algo_note( int algo )
{
  if(algo >= 100 && algo <= 110)
    {
      static int warn=0;
      if(!warn)
	{
	  warn=1;
	  log_info (_("WARNING: using experimental public key algorithm %s\n"),
		    gcry_pk_algo_name (algo));
	}
    }
}

void
print_cipher_algo_note( int algo )
{
  if(algo >= 100 && algo <= 110)
    {
      static int warn=0;
      if(!warn)
	{
	  warn=1;
	  log_info (_("WARNING: using experimental cipher algorithm %s\n"),
                    gcry_cipher_algo_name (algo));
	}
    }
}

void
print_digest_algo_note( int algo )
{
  if(algo >= 100 && algo <= 110)
    {
      static int warn=0;
      if(!warn)
	{
	  warn=1;
	  log_info (_("WARNING: using experimental digest algorithm %s\n"),
                    gcry_md_algo_name (algo));
	}
    }
  else if(algo==DIGEST_ALGO_MD5)
    log_info (_("WARNING: digest algorithm %s is deprecated\n"),
              gcry_md_algo_name (algo));
}

/* Return a string which is used as a kind of process ID */
const byte *
get_session_marker( size_t *rlen )
{
  static byte marker[SIZEOF_UNSIGNED_LONG*2];
  static int initialized;
  
  if ( !initialized )
    {
      volatile ulong aa, bb; /* We really want the uninitialized value. */
      ulong a, b;
      
      initialized = 1;
      /* Although this marker is guessable it is not easy to use this
       * for a faked control packet because an attacker does not have
       * enough control about the time the verification takes place.
       * Of course, we could add just more random but than we need the
       * random generator even for verification tasks - which does not
       * make sense. */
      a = aa ^ (ulong)getpid();
      b = bb ^ (ulong)time(NULL);
      memcpy ( marker, &a, SIZEOF_UNSIGNED_LONG );
      memcpy ( marker+SIZEOF_UNSIGNED_LONG, &b, SIZEOF_UNSIGNED_LONG );
    }
  *rlen = sizeof(marker);
  return marker;
}

/****************
 * Wrapper around the libgcrypt function with additonal checks on
 * the OpenPGP contraints for the algo ID.
 */
int
openpgp_cipher_test_algo( int algo )
{
  if ( algo < 0 || algo > 110 )
    return gpg_error (GPG_ERR_CIPHER_ALGO);
  return gcry_cipher_test_algo (algo);
}

int
openpgp_pk_test_algo( int algo )
{
  if (algo == GCRY_PK_ELG_E)
    algo = GCRY_PK_ELG;

  if (algo < 0 || algo > 110)
    return gpg_error (GPG_ERR_PUBKEY_ALGO);
  return gcry_pk_test_algo (algo);
}

int
openpgp_pk_test_algo2( int algo, unsigned int use )
{
  size_t use_buf = use;

  if (algo == GCRY_PK_ELG_E)
    algo = GCRY_PK_ELG;

  if (algo < 0 || algo > 110)
    return gpg_error (GPG_ERR_PUBKEY_ALGO);

  return gcry_pk_algo_info (algo, GCRYCTL_TEST_ALGO, NULL, &use_buf);
}

int 
openpgp_pk_algo_usage ( int algo )
{
    int use = 0; 
    
    /* They are hardwired in gpg 1.0. */
    switch ( algo ) {    
      case PUBKEY_ALGO_RSA:
          use = (PUBKEY_USAGE_CERT | PUBKEY_USAGE_SIG
                 | PUBKEY_USAGE_ENC | PUBKEY_USAGE_AUTH);
          break;
      case PUBKEY_ALGO_RSA_E:
          use = PUBKEY_USAGE_ENC;
          break;
      case PUBKEY_ALGO_RSA_S:
          use = PUBKEY_USAGE_CERT | PUBKEY_USAGE_SIG;
          break;
      case PUBKEY_ALGO_ELGAMAL_E:
          use = PUBKEY_USAGE_ENC;
          break;
      case PUBKEY_ALGO_DSA:  
          use = PUBKEY_USAGE_CERT | PUBKEY_USAGE_SIG | PUBKEY_USAGE_AUTH;
          break;
      default:
          break;
    }
    return use;
}

int
openpgp_md_test_algo( int algo )
{
  if (algo < 0 || algo > 110)
    return gpg_error (GPG_ERR_DIGEST_ALGO);
  return gcry_md_test_algo (algo);
}

#ifdef USE_IDEA
/* Special warning for the IDEA cipher */
void
idea_cipher_warn(int show)
{
  static int warned=0;

  if(!warned || show)
    {
      log_info(_("the IDEA cipher plugin is not present\n"));
      log_info(_("please see %s for more information\n"),
               "http://www.gnupg.org/faq/why-not-idea.html");
      warned=1;
    }
}
#endif


static unsigned long 
get_signature_count (PKT_secret_key *sk)
{
#ifdef ENABLE_CARD_SUPPORT
  if(sk && sk->is_protected && sk->protect.s2k.mode==1002)
    {
      struct agent_card_info_s info;
      if(agent_scd_getattr("SIG-COUNTER",&info)==0)
	return info.sig_counter;
    }  
#endif

  /* How to do this without a card? */

  return 0;
}

/* Expand %-strings.  Returns a string which must be xfreed.  Returns
   NULL if the string cannot be expanded (too large). */
char *
pct_expando(const char *string,struct expando_args *args)
{
  const char *ch=string;
  int idx=0,maxlen=0,done=0;
  u32 pk_keyid[2]={0,0},sk_keyid[2]={0,0};
  char *ret=NULL;

  if(args->pk)
    keyid_from_pk(args->pk,pk_keyid);

  if(args->sk)
    keyid_from_sk(args->sk,sk_keyid);

  /* This is used so that %k works in photoid command strings in
     --list-secret-keys (which of course has a sk, but no pk). */
  if(!args->pk && args->sk)
    keyid_from_sk(args->sk,pk_keyid);

  while(*ch!='\0')
    {
      char *str=NULL;

      if(!done)
	{
	  /* 8192 is way bigger than we'll need here */
	  if(maxlen>=8192)
	    goto fail;

	  maxlen+=1024;
	  ret=xrealloc(ret,maxlen);
	}

      done=0;

      if(*ch=='%')
	{
	  switch(*(ch+1))
	    {
	    case 's': /* short key id */
	      if(idx+8<maxlen)
		{
		  sprintf(&ret[idx],"%08lX",(ulong)sk_keyid[1]);
		  idx+=8;
		  done=1;
		}
	      break;

	    case 'S': /* long key id */
	      if(idx+16<maxlen)
		{
		  sprintf(&ret[idx],"%08lX%08lX",
			  (ulong)sk_keyid[0],(ulong)sk_keyid[1]);
		  idx+=16;
		  done=1;
		}
	      break;

	    case 'k': /* short key id */
	      if(idx+8<maxlen)
		{
		  sprintf(&ret[idx],"%08lX",(ulong)pk_keyid[1]);
		  idx+=8;
		  done=1;
		}
	      break;

	    case 'K': /* long key id */
	      if(idx+16<maxlen)
		{
		  sprintf(&ret[idx],"%08lX%08lX",
			  (ulong)pk_keyid[0],(ulong)pk_keyid[1]);
		  idx+=16;
		  done=1;
		}
	      break;

	    case 'c': /* signature count from card, if any. */
	      if(idx+10<maxlen)
		{
		  sprintf(&ret[idx],"%lu",get_signature_count(args->sk));
		  idx+=strlen(&ret[idx]);
		  done=1;
		}	      
	      break;

	    case 'p': /* primary pk fingerprint of a sk */
	    case 'f': /* pk fingerprint */
	    case 'g': /* sk fingerprint */
	      {
		byte array[MAX_FINGERPRINT_LEN];
		size_t len;
		int i;

		if((*(ch+1))=='p' && args->sk)
		  {
		    if(args->sk->is_primary)
		      fingerprint_from_sk(args->sk,array,&len);
		    else if(args->sk->main_keyid[0] || args->sk->main_keyid[1])
		      {
			PKT_public_key *pk=
			  xmalloc_clear(sizeof(PKT_public_key));

			if(get_pubkey_fast(pk,args->sk->main_keyid)==0)
			  fingerprint_from_pk(pk,array,&len);
			else
			  memset(array,0,(len=MAX_FINGERPRINT_LEN));
			free_public_key(pk);
		      }
		    else
		      memset(array,0,(len=MAX_FINGERPRINT_LEN));
		  }
		else if((*(ch+1))=='f' && args->pk)
		  fingerprint_from_pk(args->pk,array,&len);
		else if((*(ch+1))=='g' && args->sk)
		  fingerprint_from_sk(args->sk,array,&len);
		else
		  memset(array,0,(len=MAX_FINGERPRINT_LEN));

		if(idx+(len*2)<maxlen)
		  {
		    for(i=0;i<len;i++)
		      {
			sprintf(&ret[idx],"%02X",array[i]);
			idx+=2;
		      }
		    done=1;
		  }
	      }
	      break;

	    case 't': /* e.g. "jpg" */
	      str=image_type_to_string(args->imagetype,0);
	      /* fall through */

	    case 'T': /* e.g. "image/jpeg" */
	      if(str==NULL)
		str=image_type_to_string(args->imagetype,2);

	      if(idx+strlen(str)<maxlen)
		{
		  strcpy(&ret[idx],str);
		  idx+=strlen(str);
		  done=1;
		}
	      break;

	    case '%':
	      if(idx+1<maxlen)
		{
		  ret[idx++]='%';
		  ret[idx]='\0';
		  done=1;
		}
	      break;

	      /* Any unknown %-keys (like %i, %o, %I, and %O) are
		 passed through for later expansion.  Note this also
		 handles the case where the last character in the
		 string is a '%' - the terminating \0 will end up here
		 and properly terminate the string. */
	    default:
	      if(idx+2<maxlen)
		{
		  ret[idx++]='%';
		  ret[idx++]=*(ch+1);
		  ret[idx]='\0';
		  done=1;
		}
	      break;
	      }

	  if(done)
	    ch++;
	}
      else
	{
	  if(idx+1<maxlen)
	    {
	      ret[idx++]=*ch;
	      ret[idx]='\0';
	      done=1;
	    }
	}

      if(done)
	ch++;
    }

  return ret;

 fail:
  xfree(ret);
  return NULL;
}

void
deprecated_warning(const char *configname,unsigned int configlineno,
		   const char *option,const char *repl1,const char *repl2)
{
  if(configname)
    {
      if(strncmp("--",option,2)==0)
	option+=2;

      if(strncmp("--",repl1,2)==0)
	repl1+=2;

      log_info(_("%s:%d: deprecated option \"%s\"\n"),
	       configname,configlineno,option);
    }
  else
    log_info(_("WARNING: \"%s\" is a deprecated option\n"),option);

  log_info(_("please use \"%s%s\" instead\n"),repl1,repl2);
}


void
deprecated_command (const char *name)
{
  log_info(_("WARNING: \"%s\" is a deprecated command - do not use it\n"),
           name);
}


/*
 * Wrapper around gcry_cipher_map_name to provide a fallback using the
 * "Sn" syntax as used by the preference strings.
 */
int 
string_to_cipher_algo (const char *string) 
{ 
  int val;

  val = gcry_cipher_map_name (string);
  if (!val && string && (string[0]=='S' || string[0]=='s'))
    {
      char *endptr;

      string++;
      val = strtol (string, &endptr, 10);
      if (!*string || *endptr || openpgp_cipher_test_algo (val))
        val = 0;
    }

  return val;
}

/*
 * Wrapper around gcry_md_map_name to provide a fallback using the
 * "Hn" syntax as used by the preference strings.
 */
int 
string_to_digest_algo (const char *string) 
{ 
  int val;

  val = gcry_md_map_name (string);
  if (!val && string && (string[0]=='H' || string[0]=='h'))
    {
      char *endptr;

      string++;
      val = strtol (string, &endptr, 10);
      if (!*string || *endptr || openpgp_md_test_algo (val))
        val = 0;
    }

  return val;
}



const char *
compress_algo_to_string(int algo)
{
  const char *s=NULL;

  switch(algo)
    {
    case COMPRESS_ALGO_NONE:
      s=_("Uncompressed");
      break;

    case COMPRESS_ALGO_ZIP:
      s="ZIP";
      break;

    case COMPRESS_ALGO_ZLIB:
      s="ZLIB";
      break;

#ifdef HAVE_BZIP2
    case COMPRESS_ALGO_BZIP2:
      s="BZIP2";
      break;
#endif
    }

  return s;
}

int
string_to_compress_algo(const char *string)
{
  /* TRANSLATORS: See doc/TRANSLATE about this string. */
  if(match_multistr(_("uncompressed|none"),string))
    return 0;
  else if(ascii_strcasecmp(string,"uncompressed")==0)
    return 0;
  else if(ascii_strcasecmp(string,"none")==0)
    return 0;
  else if(ascii_strcasecmp(string,"zip")==0)
    return 1;
  else if(ascii_strcasecmp(string,"zlib")==0)
    return 2;
#ifdef HAVE_BZIP2
  else if(ascii_strcasecmp(string,"bzip2")==0)
    return 3;
#endif
  else if(ascii_strcasecmp(string,"z0")==0)
    return 0;
  else if(ascii_strcasecmp(string,"z1")==0)
    return 1;
  else if(ascii_strcasecmp(string,"z2")==0)
    return 2;
#ifdef HAVE_BZIP2
  else if(ascii_strcasecmp(string,"z3")==0)
    return 3;
#endif
  else
    return -1;
}

int
check_compress_algo(int algo)
{
#ifdef HAVE_BZIP2
  if(algo>=0 && algo<=3)
    return 0;
#else
  if(algo>=0 && algo<=2)
    return 0;
#endif

  return G10ERR_COMPR_ALGO;
}

int
default_cipher_algo(void)
{
  if(opt.def_cipher_algo)
    return opt.def_cipher_algo;
  else if(opt.personal_cipher_prefs)
    return opt.personal_cipher_prefs[0].value;
  else
    return opt.s2k_cipher_algo;
}

/* There is no default_digest_algo function, but see
   sign.c:hash_for() */

int
default_compress_algo(void)
{
  if(opt.compress_algo!=-1)
    return opt.compress_algo;
  else if(opt.personal_compress_prefs)
    return opt.personal_compress_prefs[0].value;
  else
    return DEFAULT_COMPRESS_ALGO;
}

const char *
compliance_option_string(void)
{
  switch(opt.compliance)
    {
    case CO_RFC2440:
      return "--openpgp";
    case CO_PGP2:
      return "--pgp2";
    case CO_PGP6:
      return "--pgp6";
    case CO_PGP7:
      return "--pgp7";
    case CO_PGP8:
      return "--pgp8";
    default:
      return "???";
    }
}

static const char *
compliance_string(void)
{
  switch(opt.compliance)
    {
    case CO_RFC2440:
      return "OpenPGP";
    case CO_PGP2:
      return "PGP 2.x";
    case CO_PGP6:
      return "PGP 6.x";
    case CO_PGP7:
      return "PGP 7.x";
    case CO_PGP8:
      return "PGP 8.x";
    default:
      return "???";
    }
}

void
compliance_failure(void)
{
  log_info(_("this message may not be usable by %s\n"),compliance_string());
  opt.compliance=CO_GNUPG;
}

/* Break a string into successive option pieces.  Accepts single word
   options and key=value argument options. */
char *
optsep(char **stringp)
{
  char *tok,*end;

  tok=*stringp;
  if(tok)
    {
      end=strpbrk(tok," ,=");
      if(end)
	{
	  int sawequals=0;
	  char *ptr=end;

	  /* what we need to do now is scan along starting with *end,
	     If the next character we see (ignoring spaces) is an =
	     sign, then there is an argument. */

	  while(*ptr)
	    {
	      if(*ptr=='=')
		sawequals=1;
	      else if(*ptr!=' ')
		break;
	      ptr++;
	    }

	  /* There is an argument, so grab that too.  At this point,
	     ptr points to the first character of the argument. */
	  if(sawequals)
	    {
	      /* Is it a quoted argument? */
	      if(*ptr=='"')
		{
		  ptr++;
		  end=strchr(ptr,'"');
		  if(end)
		    end++;
		}
	      else
		end=strpbrk(ptr," ,");
	    }

	  if(end && *end)
	    {
	      *end='\0';
	      *stringp=end+1;
	    }
	  else
	    *stringp=NULL;
	}
      else
	*stringp=NULL;
    }

  return tok;
}

/* Breaks an option value into key and value.  Returns NULL if there
   is no value.  Note that "string" is modified to remove the =value
   part. */
char *
argsplit(char *string)
{
  char *equals,*arg=NULL;

  equals=strchr(string,'=');
  if(equals)
    {
      char *quote,*space;

      *equals='\0';
      arg=equals+1;

      /* Quoted arg? */
      quote=strchr(arg,'"');
      if(quote)
	{
	  arg=quote+1;

	  quote=strchr(arg,'"');
	  if(quote)
	    *quote='\0';
	}
      else
	{
	  size_t spaces;

	  /* Trim leading spaces off of the arg */
	  spaces=strspn(arg," ");
	  arg+=spaces;
	}

      /* Trim tailing spaces off of the tag */
      space=strchr(string,' ');
      if(space)
	*space='\0';
    }

  return arg;
}

/* Return the length of the initial token, leaving off any
   argument. */
static size_t
optlen(const char *s)
{
  char *end=strpbrk(s," =");

  if(end)
    return end-s;
  else
    return strlen(s);
}

int
parse_options(char *str,unsigned int *options,
	      struct parse_options *opts,int noisy)
{
  char *tok;

  if (str && !strcmp (str, "help"))
    {
      int i,maxlen=0;

      /* Figure out the longest option name so we can line these up
	 neatly. */
      for(i=0;opts[i].name;i++)
	if(opts[i].help && maxlen<strlen(opts[i].name))
	  maxlen=strlen(opts[i].name);

      for(i=0;opts[i].name;i++)
        if(opts[i].help)
	  printf("%s%*s%s\n",opts[i].name,
		 maxlen+2-(int)strlen(opts[i].name),"",_(opts[i].help));

      g10_exit(0);
    }

  while((tok=optsep(&str)))
    {
      int i,rev=0;
      char *otok=tok;

      if(tok[0]=='\0')
	continue;

      if(ascii_strncasecmp("no-",tok,3)==0)
	{
	  rev=1;
	  tok+=3;
	}

      for(i=0;opts[i].name;i++)
	{
	  size_t toklen=optlen(tok);

	  if(ascii_strncasecmp(opts[i].name,tok,toklen)==0)
	    {
	      /* We have a match, but it might be incomplete */
	      if(toklen!=strlen(opts[i].name))
		{
		  int j;

		  for(j=i+1;opts[j].name;j++)
		    {
		      if(ascii_strncasecmp(opts[j].name,tok,toklen)==0)
			{
			  if(noisy)
			    log_info(_("ambiguous option `%s'\n"),otok);
			  return 0;
			}
		    }
		}

	      if(rev)
		{
		  *options&=~opts[i].bit;
		  if(opts[i].value)
		    *opts[i].value=NULL;
		}
	      else
		{
		  *options|=opts[i].bit;
		  if(opts[i].value)
		    *opts[i].value=argsplit(tok);
		}
	      break;
	    }
	}

      if(!opts[i].name)
	{
	  if(noisy)
	    log_info(_("unknown option `%s'\n"),otok);
	  return 0;
	}
    }

  return 1;
}


/* Return a new malloced string by unescaping the string S.  Escaping
   is percent escaping and '+'/space mapping.  A binary nul will
   silently be replaced by a 0xFF. */
char *
unescape_percent_string (const unsigned char *s)
{
  char *buffer, *d;

  buffer = d = xmalloc (strlen (s)+1);
  while (*s)
    {
      if (*s == '%' && s[1] && s[2])
        { 
          s++;
          *d = xtoi_2 (s);
          if (!*d)
            *d = '\xff';
          d++;
          s += 2;
        }
      else if (*s == '+')
        {
          *d++ = ' ';
          s++;
        }
      else
        *d++ = *s++;
    }
  *d = 0; 
  return buffer;
}


int
has_invalid_email_chars (const char *s)
{
  int at_seen=0;
  const char *valid_chars=
    "01234567890_-.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

  for ( ; *s; s++ ) 
    {
      if ( *s & 0x80 )
        return 1;
      if ( *s == '@' )
        at_seen=1;
      else if ( !at_seen && !( !!strchr( valid_chars, *s ) || *s == '+' ) )
        return 1;
      else if ( at_seen && !strchr( valid_chars, *s ) )
        return 1;
    }
  return 0;
}


/* Check whether NAME represents a valid mailbox according to
   RFC822. Returns true if so. */
int
is_valid_mailbox (const char *name)
{
  return !( !name
            || !*name
            || has_invalid_email_chars (name)
            || string_count_chr (name,'@') != 1
            || *name == '@'
            || name[strlen(name)-1] == '@'
            || name[strlen(name)-1] == '.'
            || strstr (name, "..") );
}


/* This is a helper function to load a Windows function from either of
   one DLLs. */
#ifdef HAVE_W32_SYSTEM
static HRESULT
w32_shgetfolderpath (HWND a, int b, HANDLE c, DWORD d, LPSTR e)
{
  static int initialized;
  static HRESULT (WINAPI * func)(HWND,int,HANDLE,DWORD,LPSTR);

  if (!initialized)
    {
      static char *dllnames[] = { "shell32.dll", "shfolder.dll", NULL };
      void *handle;
      int i;

      initialized = 1;

      for (i=0, handle = NULL; !handle && dllnames[i]; i++)
        {
          handle = dlopen (dllnames[i], RTLD_LAZY);
          if (handle)
            {
              func = dlsym (handle, "SHGetFolderPathA");
              if (!func)
                {
                  dlclose (handle);
                  handle = NULL;
                }
            }
        }
    }

  if (func)
    return func (a,b,c,d,e);
  else
    return -1;
}
#endif /*HAVE_W32_SYSTEM*/


/* Return the name of the libexec directory.  The name is allocated in
   a static area on the first use.  This function won't fail. */
const char *
get_libexecdir (void)
{
#ifdef HAVE_W32_SYSTEM
  static int got_dir;
  static char dir[MAX_PATH+5];

  if (!got_dir)
    {
      char *p;

      if ( !GetModuleFileName ( NULL, dir, MAX_PATH) )
        {
          log_debug ("GetModuleFileName failed: %s\n", w32_strerror (0));
          *dir = 0;
        }
      got_dir = 1;
      p = strrchr (dir, DIRSEP_C);
      if (p)
        *p = 0;
      else
        {
          log_debug ("bad filename `%s' returned for this process\n", dir);
          *dir = 0; 
        }
    }

  if (*dir)
    return dir;
  /* Fallback to the hardwired value. */
#endif /*HAVE_W32_SYSTEM*/

  return GNUPG_LIBEXECDIR;
}

/* Similar to access(2), but uses PATH to find the file. */
int
path_access(const char *file,int mode)
{
  char *envpath;
  int ret=-1;

  envpath=getenv("PATH");

  if(!envpath
#ifdef HAVE_DRIVE_LETTERS
     || (((file[0]>='A' && file[0]<='Z')
	  || (file[0]>='a' && file[0]<='z'))
	 && file[1]==':')
#else
     || file[0]=='/'
#endif
     )
    return access(file,mode);
  else
    {
      /* At least as large as, but most often larger than we need. */
      char *buffer=xmalloc(strlen(envpath)+1+strlen(file)+1);
      char *split,*item,*path=xstrdup(envpath);

      split=path;

      while((item=strsep(&split,PATHSEP_S)))
	{
	  strcpy(buffer,item);
	  strcat(buffer,"/");
	  strcat(buffer,file);
	  ret=access(buffer,mode);
	  if(ret==0)
	    break;
	}

      xfree(path);
      xfree(buffer);
    }

  return ret;
}



/* Temporary helper. */
int
pubkey_get_npkey( int algo )
{
  size_t n;

  if (algo == GCRY_PK_ELG_E)
    algo = GCRY_PK_ELG;
  if (gcry_pk_algo_info( algo, GCRYCTL_GET_ALGO_NPKEY, NULL, &n))
    n = 0;
  return n;
}

/* Temporary helper. */
int
pubkey_get_nskey( int algo )
{
  size_t n;

  if (algo == GCRY_PK_ELG_E)
    algo = GCRY_PK_ELG;
  if (gcry_pk_algo_info( algo, GCRYCTL_GET_ALGO_NSKEY, NULL, &n ))
    n = 0;
  return n;
}

/* Temporary helper. */
int
pubkey_get_nsig( int algo )
{
  size_t n;

  if (algo == GCRY_PK_ELG_E)
    algo = GCRY_PK_ELG;
  if (gcry_pk_algo_info( algo, GCRYCTL_GET_ALGO_NSIGN, NULL, &n))
    n = 0;
  return n;
}

/* Temporary helper. */
int
pubkey_get_nenc( int algo )
{
  size_t n;
  
  if (algo == GCRY_PK_ELG_E)
    algo = GCRY_PK_ELG;
  if (gcry_pk_algo_info( algo, GCRYCTL_GET_ALGO_NENCR, NULL, &n ))
    n = 0;
  return n;
}


/* Temporary helper. */
unsigned int
pubkey_nbits( int algo, gcry_mpi_t *key )
{
    int rc, nbits;
    gcry_sexp_t sexp;

    if( algo == GCRY_PK_DSA ) {
	rc = gcry_sexp_build ( &sexp, NULL,
			      "(public-key(dsa(p%m)(q%m)(g%m)(y%m)))",
				  key[0], key[1], key[2], key[3] );
    }
    else if( algo == GCRY_PK_ELG || algo == GCRY_PK_ELG_E ) {
	rc = gcry_sexp_build ( &sexp, NULL,
			      "(public-key(elg(p%m)(g%m)(y%m)))",
				  key[0], key[1], key[2] );
    }
    else if( algo == GCRY_PK_RSA ) {
	rc = gcry_sexp_build ( &sexp, NULL,
			      "(public-key(rsa(n%m)(e%m)))",
				  key[0], key[1] );
    }
    else
	return 0;

    if ( rc )
	BUG ();

    nbits = gcry_pk_get_nbits( sexp );
    gcry_sexp_release( sexp );
    return nbits;
}



/* FIXME: Use gcry_mpi_print directly. */
int
mpi_print( FILE *fp, gcry_mpi_t a, int mode )
{
    int n=0;

    if( !a )
	return fprintf(fp, "[MPI_NULL]");
    if( !mode ) {
	unsigned int n1;
	n1 = gcry_mpi_get_nbits(a);
	n += fprintf(fp, "[%u bits]", n1);
    }
    else {
	unsigned char *buffer;

	if (gcry_mpi_aprint (GCRYMPI_FMT_HEX, &buffer, NULL, a))
          BUG ();
	fputs( buffer, fp );
	n += strlen(buffer);
	gcry_free( buffer );
    }
    return n;
}