gnupg/util/fileutil.c

/* fileutil.c -  file utilities
 * Copyright (C) 1998, 2003, 2005 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 <stdarg.h>
#include <string.h>
#include <assert.h>
#include <unistd.h>
#include <sys/types.h>
#ifdef HAVE_PWD_H
#include <pwd.h>
#endif
#include "util.h"
#include "memory.h"
#include "ttyio.h"


/***************
 * Extract from a given path the filename component.
 *
 */
char *
make_basename(const char *filepath, const char *inputpath)
{
#ifdef __riscos__
    return riscos_make_basename(filepath, inputpath);
#endif

    char *p;

    if ( !(p=strrchr(filepath, DIRSEP_C)) )
#ifdef HAVE_DRIVE_LETTERS
	if ( !(p=strrchr(filepath, '\\')) )
	    if ( !(p=strrchr(filepath, ':')) )
#endif
	      {
		return xstrdup(filepath);
	      }

    return xstrdup(p+1);
}



/***************
 * Extract from a given filename the path prepended to it.
 * If their isn't a path prepended to the filename, a dot
 * is returned ('.').
 *
 */
char *
make_dirname(const char *filepath)
{
    char *dirname;
    int  dirname_length;
    char *p;

    if ( !(p=strrchr(filepath, DIRSEP_C)) )
#ifdef HAVE_DRIVE_LETTERS
	if ( !(p=strrchr(filepath, '\\')) )
	    if ( !(p=strrchr(filepath, ':')) )
#endif
	      {
		return xstrdup(EXTSEP_S);
	      }

    dirname_length = p-filepath;
    dirname = xmalloc(dirname_length+1);
    strncpy(dirname, filepath, dirname_length);
    dirname[dirname_length] = 0;

    return dirname;
}

/* Expand tildes.  Handles both the ~/foo and ~username/foo cases.
   Returns what the tilde expands to.  *name is advanced to be past
   the tilde expansion. */
static char *
untilde(const char **name)
{
  char *home=NULL;

  assert((*name)[0]=='~');

  if((*name)[1]==DIRSEP_C || (*name)[1]=='\0')
    {
      /* This is the "~/foo" or "~" case. */
      char *tmp=getenv("HOME");
      if(tmp)
	home=xstrdup(tmp);

#ifdef HAVE_GETPWUID
      if(!home)
	{
	  struct passwd *pwd;

	  pwd=getpwuid(getuid());
	  if(pwd)
	    home=xstrdup(pwd->pw_dir);
	}
#endif
      if(home)
	(*name)++;
    }
#ifdef HAVE_GETPWNAM
  else
    {
      /* This is the "~username" case. */
      char *user,*sep;
      struct passwd *pwd;

      user=xstrdup((*name)+1);

      sep=strchr(user,DIRSEP_C);
      if(sep)
	*sep='\0';

      pwd=getpwnam(user);
      if(pwd)
	{
	  home=xstrdup(pwd->pw_dir);
	  (*name)+=1+strlen(user);
	}

      xfree(user);
    }
#endif

  return home;
}

/*
  Construct a filename from the NULL terminated list of parts.  Tilde
  expansion is done here.  Note that FIRST_PART must never be NULL and
  that this function is guaranteed to return an allocated string.  */
char *
make_filename( const char *first_part, ... )
{
    va_list arg_ptr ;
    size_t n;
    const char *s;
    char *name, *p, *home=NULL;

    va_start( arg_ptr, first_part ) ;
    n = strlen(first_part)+1;
    while( (s=va_arg(arg_ptr, const char *)) )
	n += strlen(s) + 1;
    va_end(arg_ptr);

#ifndef __riscos__
    if(*first_part=='~')
      {
	home=untilde(&first_part);
	if(home)
	  n+=strlen(home);
      }
#endif
    name = xmalloc(n);
    p = home ? stpcpy(stpcpy(name,home), first_part)
	     : stpcpy(name, first_part);
    va_start( arg_ptr, first_part ) ;
    while( (s=va_arg(arg_ptr, const char *)) )
	p = stpcpy(stpcpy(p, DIRSEP_S), s);
    va_end(arg_ptr);
    xfree(home);

#ifndef __riscos__
    return name;
#else /* __riscos__ */
    p = riscos_gstrans(name);
    xfree(name);
    return p;
#endif /* __riscos__ */
}


int
compare_filenames( const char *a, const char *b )
{
    /* ? check whether this is an absolute filename and
     * resolve symlinks?
     */
#ifndef __riscos__
#ifdef HAVE_DRIVE_LETTERS
    return ascii_strcasecmp(a,b);
#else
    return strcmp(a,b);
#endif
#else /* __riscos__ */
    int c = 0;
    char *abuf, *bbuf;

    abuf = riscos_gstrans(a);
    bbuf = riscos_gstrans(b);

    c = ascii_strcasecmp (abuf, bbuf);

    xfree(abuf);
    xfree(bbuf);

    return c;
#endif /* __riscos__ */
}


/****************
 * A simple function to decide whether the filename is stdout
 * or a real filename.
 */
const char *
print_fname_stdout( const char *s )
{
    if( !s || (*s == '-' && !s[1]) )
	return "[stdout]";
    return s;
}


const char *
print_fname_stdin( const char *s )
{
    if( !s || (*s == '-' && !s[1]) )
	return "[stdin]";
    return s;
}

/****************
 * Check if the file is compressed.
 **/
int
is_file_compressed( const char *s, int *ret_rc )
{
    IOBUF a;
    byte buf[4];
    int i, rc = 0;
    int overflow;

    struct magic_compress_s {
        size_t len;
        byte magic[4];
    } magic[] = {
        { 3, { 0x42, 0x5a, 0x68, 0x00 } }, /* bzip2 */
        { 3, { 0x1f, 0x8b, 0x08, 0x00 } }, /* gzip */
        { 4, { 0x50, 0x4b, 0x03, 0x04 } }, /* (pk)zip */
    };
    
    if ( iobuf_is_pipe_filename (s) || !ret_rc )
        return 0; /* We can't check stdin or no file was given */

    a = iobuf_open( s );
    if ( a == NULL ) {
        *ret_rc = G10ERR_OPEN_FILE;
        return 0;
    }

    if ( iobuf_get_filelength( a, &overflow ) < 4 && !overflow) {
        *ret_rc = 0;
        goto leave;
    }

    if ( iobuf_read( a, buf, 4 ) == -1 ) {
        *ret_rc = G10ERR_READ_FILE;
        goto leave;
    }

    for ( i = 0; i < DIM( magic ); i++ ) {
        if ( !memcmp( buf, magic[i].magic, magic[i].len ) ) {
            *ret_rc = 0;
            rc = 1;
            break;
        }
    }

leave:    
    iobuf_close( a );
    return rc;
}