kbx/keybox-file.c

   1 /* keybox-file.c - file oeprations
   2  *      Copyright (C) 2001, 2003 Free Software Foundation, Inc.
   3  *
   4  * This file is part of GnuPG.
   5  *
   6  * GnuPG is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * GnuPG is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  19  * USA.
  20  */
  21
  22 #include <config.h>
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <errno.h>
  27 #include <time.h>
  28
  29 #include "keybox-defs.h"
  30
  31
  32 #if !defined(HAVE_FTELLO) && !defined(ftello)
  33 static off_t
  34 ftello (FILE *stream)
  35 {
  36   long int off;
  37
  38   off = ftell (stream);
  39   if (off == -1)
  40     return (off_t)-1;
  41   return off;
  42 }
  43 #endif /* !defined(HAVE_FTELLO) && !defined(ftello) */
  44
  45
  46
  47 /* Read a block at the current postion and return it in r_blob.
  48    r_blob may be NULL to simply skip the current block */
  49 int
  50 _keybox_read_blob2 (KEYBOXBLOB *r_blob, FILE *fp, int *skipped_deleted)
  51 {
  52   unsigned char *image;
  53   size_t imagelen = 0;
  54   int c1, c2, c3, c4, type;
  55   int rc;
  56   off_t off;
  57
  58   *skipped_deleted = 0;
  59  again:
  60   *r_blob = NULL;
  61   off = ftello (fp);
  62   if (off == (off_t)-1)
  63     return gpg_error (gpg_err_code_from_errno (errno));
  64
  65   if ((c1 = getc (fp)) == EOF
  66       || (c2 = getc (fp)) == EOF
  67       || (c3 = getc (fp)) == EOF
  68       || (c4 = getc (fp)) == EOF
  69       || (type = getc (fp)) == EOF)
  70     {
  71       if ( c1 == EOF && !ferror (fp) )
  72         return -1; /* eof */
  73       return gpg_error (gpg_err_code_from_errno (errno));
  74     }
  75
  76   imagelen = (c1 << 24) | (c2 << 16) | (c3 << 8 ) | c4;
  77   if (imagelen > 500000) /* Sanity check. */
  78     return gpg_error (GPG_ERR_TOO_LARGE);
  79
  80   if (imagelen < 5)
  81     return gpg_error (GPG_ERR_TOO_SHORT);
  82
  83   if (!type)
  84     {
  85       /* Special treatment for empty blobs. */
  86       if (fseek (fp, imagelen-5, SEEK_CUR))
  87         return gpg_error (gpg_err_code_from_errno (errno));
  88       *skipped_deleted = 1;
  89       goto again;
  90     }
  91
  92   image = xtrymalloc (imagelen);
  93   if (!image)
  94     return gpg_error (gpg_err_code_from_errno (errno));
  95
  96   image[0] = c1; image[1] = c2; image[2] = c3; image[3] = c4; image[4] = type;
  97   if (fread (image+5, imagelen-5, 1, fp) != 1)
  98     {
  99       gpg_error_t tmperr = gpg_error (gpg_err_code_from_errno (errno));
 100       xfree (image);
 101       return tmperr;
 102     }
 103
 104   rc = r_blob? _keybox_new_blob (r_blob, image, imagelen, off) : 0;
 105   if (rc || !r_blob)
 106         xfree (image);
 107   return rc;
 108 }
 109
 110 int
 111 _keybox_read_blob (KEYBOXBLOB *r_blob, FILE *fp)
 112 {
 113   int dummy;
 114   return _keybox_read_blob2 (r_blob, fp, &dummy);
 115 }
 116
 117
 118 /* Write the block to the current file position */
 119 int
 120 _keybox_write_blob (KEYBOXBLOB blob, FILE *fp)
 121 {
 122   const unsigned char *image;
 123   size_t length;
 124
 125   image = _keybox_get_blob_image (blob, &length);
 126   if (fwrite (image, length, 1, fp) != 1)
 127     return gpg_error (gpg_err_code_from_errno (errno));
 128   return 0;
 129 }
 130
 131
 132 /* Write a fresh header type blob. */
 133 int
 134 _keybox_write_header_blob (FILE *fp)
 135 {
 136   unsigned char image[32];
 137   u32 val;
 138
 139   memset (image, 0, sizeof image);
 140   /* Length of this blob. */
 141   image[3] = 32;
 142
 143   image[4] = BLOBTYPE_HEADER;
 144   image[5] = 1; /* Version */
 145
 146   memcpy (image+8, "KBXf", 4);
 147   val = time (NULL);
 148   /* created_at and last maintenance run. */
 149   image[16]   = (val >> 24);
 150   image[16+1] = (val >> 16);
 151   image[16+2] = (val >>  8);
 152   image[16+3] = (val      );
 153   image[20]   = (val >> 24);
 154   image[20+1] = (val >> 16);
 155   image[20+2] = (val >>  8);
 156   image[20+3] = (val      );
 157
 158   if (fwrite (image, 32, 1, fp) != 1)
 159     return gpg_error (gpg_err_code_from_errno (errno));
 160   return 0;
 161 }
 162
 163