src/journal/journal-qrcode.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2012 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <assert.h>
  23 #include <errno.h>
  24 #include <qrencode.h>
  25 #include <stdbool.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28
  29 #include "journal-qrcode.h"
  30
  31 #define WHITE_ON_BLACK "\033[40;37;1m"
  32 #define NORMAL "\033[0m"
  33
  34 static void print_border(FILE *output, unsigned width) {
  35         unsigned x, y;
  36
  37         /* Four rows of border */
  38         for (y = 0; y < 4; y += 2) {
  39                 fputs(WHITE_ON_BLACK, output);
  40
  41                 for (x = 0; x < 4 + width + 4; x++)
  42                         fputs("\342\226\210", output);
  43
  44                 fputs(NORMAL "\n", output);
  45         }
  46 }
  47
  48 int print_qr_code(
  49                 FILE *output,
  50                 const void *seed,
  51                 size_t seed_size,
  52                 uint64_t start,
  53                 uint64_t interval,
  54                 const char *hn,
  55                 sd_id128_t machine) {
  56
  57         FILE *f;
  58         char *url = NULL;
  59         size_t url_size = 0, i;
  60         QRcode* qr;
  61         unsigned x, y;
  62
  63         assert(seed);
  64         assert(seed_size > 0);
  65
  66         f = open_memstream(&url, &url_size);
  67         if (!f)
  68                 return -ENOMEM;
  69
  70         fputs("fss://", f);
  71
  72         for (i = 0; i < seed_size; i++) {
  73                 if (i > 0 && i % 3 == 0)
  74                         fputc('-', f);
  75                 fprintf(f, "%02x", ((uint8_t*) seed)[i]);
  76         }
  77
  78         fprintf(f, "/%"PRIx64"-%"PRIx64"?machine=" SD_ID128_FORMAT_STR,
  79                 start,
  80                 interval,
  81                 SD_ID128_FORMAT_VAL(machine));
  82
  83         if (hn)
  84                 fprintf(f, ";hostname=%s", hn);
  85
  86         if (ferror(f)) {
  87                 fclose(f);
  88                 free(url);
  89                 return -ENOMEM;
  90         }
  91
  92         fclose(f);
  93
  94         qr = QRcode_encodeString(url, 0, QR_ECLEVEL_L, QR_MODE_8, 1);
  95         free(url);
  96
  97         if (!qr)
  98                 return -ENOMEM;
  99
 100         print_border(output, qr->width);
 101
 102         for (y = 0; y < (unsigned) qr->width; y += 2) {
 103                 const uint8_t *row1, *row2;
 104
 105                 row1 = qr->data + qr->width * y;
 106                 row2 = row1 + qr->width;
 107
 108                 fputs(WHITE_ON_BLACK, output);
 109                 for (x = 0; x < 4; x++)
 110                         fputs("\342\226\210", output);
 111
 112                 for (x = 0; x < (unsigned) qr->width; x ++) {
 113                         bool a, b;
 114
 115                         a = row1[x] & 1;
 116                         b = (y+1) < (unsigned) qr->width ? (row2[x] & 1) : false;
 117
 118                         if (a && b)
 119                                 fputc(' ', output);
 120                         else if (a)
 121                                 fputs("\342\226\204", output);
 122                         else if (b)
 123                                 fputs("\342\226\200", output);
 124                         else
 125                                 fputs("\342\226\210", output);
 126                 }
 127
 128                 for (x = 0; x < 4; x++)
 129                         fputs("\342\226\210", output);
 130                 fputs(NORMAL "\n", output);
 131         }
 132
 133         print_border(output, qr->width);
 134
 135         QRcode_free(qr);
 136         return 0;
 137 }