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 3 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, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #include <time.h>
  26
  27 #include "keybox-defs.h"
  28
  29
  30 #if !defined(HAVE_FTELLO) && !defined(ftello)
  31 static off_t
  32 ftello (FILE *stream)
  33 {
  34   long int off;
  35
  36   off = ftell (stream);
  37   if (off == -1)
  38     return (off_t)-1;
  39   return off;
  40 }
  41 #endif /* !defined(HAVE_FTELLO) && !defined(ftello) */
  42
  43
  44
  45 /* Read a block at the current postion and return it in r_blob.
  46    r_blob may be NULL to simply skip the current block */
  47 int
  48 _keybox_read_blob2 (KEYBOXBLOB *r_blob, FILE *fp, int *skipped_deleted)
  49 {
  50   unsigned char *image;
  51   size_t imagelen = 0;
  52   int c1, c2, c3, c4, type;
  53   int rc;
  54   off_t off;
  55
  56   *skipped_deleted = 0;
  57  again:
  58   *r_blob = NULL;
  59   off = ftello (fp);
  60   if (off == (off_t)-1)
  61     return gpg_error (gpg_err_code_from_errno (errno));
  62
  63   if ((c1 = getc (fp)) == EOF
  64       || (c2 = getc (fp)) == EOF
  65       || (c3 = getc (fp)) == EOF
  66       || (c4 = getc (fp)) == EOF
  67       || (type = getc (fp)) == EOF)
  68     {
  69       if ( c1 == EOF && !ferror (fp) )
  70         return -1; /* eof */
  71       return gpg_error (gpg_err_code_from_errno (errno));
  72     }
  73
  74   imagelen = (c1 << 24) | (c2 << 16) | (c3 << 8 ) | c4;
  75   if (imagelen > 500000) /* Sanity check. */
  76     return gpg_error (GPG_ERR_TOO_LARGE);
  77
  78   if (imagelen < 5)
  79     return gpg_error (GPG_ERR_TOO_SHORT);
  80
  81   if (!type)
  82     {
  83       /* Special treatment for empty blobs. */
  84       if (fseek (fp, imagelen-5, SEEK_CUR))
  85         return gpg_error (gpg_err_code_from_errno (errno));
  86       *skipped_deleted = 1;
  87       goto again;
  88     }
  89
  90   image = xtrymalloc (imagelen);
  91   if (!image)
  92     return gpg_error (gpg_err_code_from_errno (errno));
  93
  94   image[0] = c1; image[1] = c2; image[2] = c3; image[3] = c4; image[4] = type;
  95   if (fread (image+5, imagelen-5, 1, fp) != 1)
  96     {
  97       gpg_error_t tmperr = gpg_error (gpg_err_code_from_errno (errno));
  98       xfree (image);
  99       return tmperr;
 100     }
 101
 102   rc = r_blob? _keybox_new_blob (r_blob, image, imagelen, off) : 0;
 103   if (rc || !r_blob)
 104         xfree (image);
 105   return rc;
 106 }
 107
 108 int
 109 _keybox_read_blob (KEYBOXBLOB *r_blob, FILE *fp)
 110 {
 111   int dummy;
 112   return _keybox_read_blob2 (r_blob, fp, &dummy);
 113 }
 114
 115
 116 /* Write the block to the current file position */
 117 int
 118 _keybox_write_blob (KEYBOXBLOB blob, FILE *fp)
 119 {
 120   const unsigned char *image;
 121   size_t length;
 122
 123   image = _keybox_get_blob_image (blob, &length);
 124   if (fwrite (image, length, 1, fp) != 1)
 125     return gpg_error (gpg_err_code_from_errno (errno));
 126   return 0;
 127 }
 128
 129
 130 /* Write a fresh header type blob. */
 131 int
 132 _keybox_write_header_blob (FILE *fp)
 133 {
 134   unsigned char image[32];
 135   u32 val;
 136
 137   memset (image, 0, sizeof image);
 138   /* Length of this blob. */
 139   image[3] = 32;
 140
 141   image[4] = BLOBTYPE_HEADER;
 142   image[5] = 1; /* Version */
 143
 144   memcpy (image+8, "KBXf", 4);
 145   val = time (NULL);
 146   /* created_at and last maintenance run. */
 147   image[16]   = (val >> 24);
 148   image[16+1] = (val >> 16);
 149   image[16+2] = (val >>  8);
 150   image[16+3] = (val      );
 151   image[20]   = (val >> 24);
 152   image[20+1] = (val >> 16);
 153   image[20+2] = (val >>  8);
 154   image[20+3] = (val      );
 155
 156   if (fwrite (image, 32, 1, fp) != 1)
 157     return gpg_error (gpg_err_code_from_errno (errno));
 158   return 0;
 159 }
 160
 161