src/shared/qrcode-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "qrcode-util.h"
   4
   5 #if HAVE_QRENCODE
   6 #include <qrencode.h>
   7 #include <stdio.h>
   8
   9 #include "ansi-color.h"
  10 #include "dlfcn-util.h"
  11 #include "locale-util.h"
  12 #include "log.h"
  13 #include "strv.h"
  14 #include "terminal-util.h"
  15
  16 #define ANSI_WHITE_ON_BLACK "\033[40;37;1m"
  17 #define UNICODE_FULL_BLOCK       UTF8("█")
  18 #define UNICODE_LOWER_HALF_BLOCK UTF8("▄")
  19 #define UNICODE_UPPER_HALF_BLOCK UTF8("▀")
  20
  21 static void *qrcode_dl = NULL;
  22
  23 static DLSYM_PROTOTYPE(QRcode_encodeString) = NULL;
  24 static DLSYM_PROTOTYPE(QRcode_free) = NULL;
  25
  26 int dlopen_qrencode(void) {
  27         int r;
  28
  29         ELF_NOTE_DLOPEN("qrencode",
  30                         "Support for generating QR codes",
  31                         ELF_NOTE_DLOPEN_PRIORITY_SUGGESTED,
  32                         "libqrencode.so.4", "libqrencode.so.3");
  33
  34         FOREACH_STRING(s, "libqrencode.so.4", "libqrencode.so.3") {
  35                 r = dlopen_many_sym_or_warn(
  36                         &qrcode_dl, s, LOG_DEBUG,
  37                         DLSYM_ARG(QRcode_encodeString),
  38                         DLSYM_ARG(QRcode_free));
  39                 if (r >= 0)
  40                         break;
  41         }
  42
  43         return r;
  44 }
  45
  46 static void print_border(FILE *output, unsigned width, unsigned row, unsigned column) {
  47         assert(output);
  48         assert(width);
  49
  50         if (row != UINT_MAX && column != UINT_MAX) {
  51                 int r, fd;
  52
  53                 fd = fileno(output);
  54                 if (fd < 0)
  55                         return (void)log_debug_errno(errno, "Failed to get file descriptor from the file stream: %m");
  56
  57                 r = terminal_set_cursor_position(fd, row, column);
  58                 if (r < 0)
  59                         log_warning_errno(r, "Failed to move terminal cursor position, ignoring: %m");
  60
  61                 /* Four rows of border */
  62                 for (unsigned y = 0; y < 4; y += 2) {
  63                         fputs(ANSI_WHITE_ON_BLACK, output);
  64
  65                         for (unsigned x = 0; x < 4 + width + 4; x++)
  66                                 fputs(UNICODE_FULL_BLOCK, output);
  67
  68                         fputs(ANSI_NORMAL "\n", output);
  69                         r = terminal_set_cursor_position(fd, row + 1, column);
  70                         if (r < 0)
  71                                 log_warning_errno(r, "Failed to move terminal cursor position, ignoring: %m");
  72                 }
  73         } else {
  74                 /* Four rows of border */
  75                 for (unsigned y = 0; y < 4; y += 2) {
  76                         fputs(ANSI_WHITE_ON_BLACK, output);
  77
  78                         for (unsigned x = 0; x < 4 + width + 4; x++)
  79                                 fputs(UNICODE_FULL_BLOCK, output);
  80
  81                         fputs(ANSI_NORMAL "\n", output);
  82                 }
  83         }
  84 }
  85
  86 static void write_qrcode(FILE *output, QRcode *qr, unsigned row, unsigned column) {
  87         assert(qr);
  88
  89         if (!output)
  90                 output = stdout;
  91
  92         print_border(output, qr->width, row, column);
  93
  94         if (row != UINT_MAX && column != UINT_MAX) {
  95                 /* After printing two rows of top border, we need to move the cursor down two rows before starting to print the actual QR code */
  96                 int r, fd, move_down = 2;
  97                 fd = fileno(output);
  98                 if (fd < 0)
  99                         return (void)log_debug_errno(errno, "Failed to get file descriptor from the file stream: %m");
 100
 101                 r = terminal_set_cursor_position(fd, row + move_down, column);
 102                 if (r < 0)
 103                         log_warning_errno(r, "Failed to move terminal cursor position, ignoring: %m");
 104
 105                 for (unsigned y = 0; y < (unsigned) qr->width; y += 2) {
 106                         const uint8_t *row1 = qr->data + qr->width * y;
 107                         const uint8_t *row2 = row1 + qr->width;
 108
 109                         fputs(ANSI_WHITE_ON_BLACK, output);
 110
 111                         for (unsigned x = 0; x < 4; x++)
 112                                 fputs(UNICODE_FULL_BLOCK, output);
 113
 114                         for (unsigned x = 0; x < (unsigned) qr->width; x++) {
 115                                 bool a, b;
 116
 117                                 a = row1[x] & 1;
 118                                 b = (y+1) < (unsigned) qr->width ? (row2[x] & 1) : false;
 119
 120                                 if (a && b)
 121                                         fputc(' ', output);
 122                                 else if (a)
 123                                         fputs(UNICODE_LOWER_HALF_BLOCK, output);
 124                                 else if (b)
 125                                         fputs(UNICODE_UPPER_HALF_BLOCK, output);
 126                                 else
 127                                         fputs(UNICODE_FULL_BLOCK, output);
 128                         }
 129
 130                         for (unsigned x = 0; x < 4; x++)
 131                                 fputs(UNICODE_FULL_BLOCK, output);
 132                         r = terminal_set_cursor_position(fd, row + move_down, column);
 133                         if (r < 0)
 134                                 log_warning_errno(r, "Failed to move terminal cursor position, ignoring: %m");
 135                         move_down += 1;
 136                         fputs(ANSI_NORMAL "\n", output);
 137                 }
 138
 139                 print_border(output, qr->width, row + move_down, column);
 140         } else {
 141
 142                 for (unsigned y = 0; y < (unsigned) qr->width; y += 2) {
 143                         const uint8_t *row1 = qr->data + qr->width * y;
 144                         const uint8_t *row2 = row1 + qr->width;
 145
 146                         fputs(ANSI_WHITE_ON_BLACK, output);
 147                         for (unsigned x = 0; x < 4; x++)
 148                                 fputs(UNICODE_FULL_BLOCK, output);
 149
 150                         for (unsigned x = 0; x < (unsigned) qr->width; x++) {
 151                                 bool a, b;
 152
 153                                 a = row1[x] & 1;
 154                                 b = (y+1) < (unsigned) qr->width ? (row2[x] & 1) : false;
 155
 156                                 if (a && b)
 157                                         fputc(' ', output);
 158                                 else if (a)
 159                                         fputs(UNICODE_LOWER_HALF_BLOCK, output);
 160                                 else if (b)
 161                                         fputs(UNICODE_UPPER_HALF_BLOCK, output);
 162                                 else
 163                                         fputs(UNICODE_FULL_BLOCK, output);
 164                         }
 165
 166                         for (unsigned x = 0; x < 4; x++)
 167                                 fputs(UNICODE_FULL_BLOCK, output);
 168                         fputs(ANSI_NORMAL "\n", output);
 169                 }
 170
 171                 print_border(output, qr->width, row, column);
 172         }
 173
 174         fflush(output);
 175 }
 176
 177 DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(QRcode*, sym_QRcode_free, NULL);
 178
 179 int print_qrcode_full(
 180                 FILE *out,
 181                 const char *header,
 182                 const char *string,
 183                 unsigned row,
 184                 unsigned column,
 185                 unsigned tty_width,
 186                 unsigned tty_height,
 187                 bool check_tty) {
 188
 189         int r;
 190
 191         /* If this is not a UTF-8 system or ANSI colors aren't supported/disabled don't print any QR
 192          * codes */
 193         if (!is_locale_utf8())
 194                 return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Not an UTF-8 system, cannot print qrcode");
 195         if (check_tty && !colors_enabled())
 196                 return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Colors are disabled, cannot print qrcode");
 197
 198         r = dlopen_qrencode();
 199         if (r < 0)
 200                 return r;
 201
 202         _cleanup_(sym_QRcode_freep) QRcode *qr =
 203                 sym_QRcode_encodeString(string, 0, QR_ECLEVEL_L, QR_MODE_8, 1);
 204         if (!qr)
 205                 return log_oom_debug();
 206
 207         if (row != UINT_MAX && column != UINT_MAX) {
 208                 unsigned qr_code_width, qr_code_height;
 209
 210                 int fd = fileno(out);
 211                 if (fd < 0)
 212                         return log_debug_errno(errno, "Failed to get file descriptor from the file stream: %m");
 213
 214                 qr_code_width = qr_code_height = qr->width + 8;
 215                 if (column + qr_code_width > tty_width)
 216                         column = tty_width - qr_code_width;
 217
 218                 /* Terminal characters are twice as high as they are wide so it's qr_code_height / 2,
 219                  * our QR code prints an extra new line, so we have -1 as well */
 220                 if (row + qr_code_height > tty_height)
 221                         row = tty_height - (qr_code_height / 2 ) - 1;
 222
 223                 if (header) {
 224                         r = terminal_set_cursor_position(fd, row - 2, tty_width - qr_code_width - 2);
 225                         if (r < 0)
 226                                 log_warning_errno(r, "Failed to move terminal cursor position, ignoring: %m");
 227
 228                         fprintf(out, "%s:\n\n", header);
 229                 }
 230         } else
 231                 if (header)
 232                         fprintf(out, "\n%s:\n\n", header);
 233
 234         write_qrcode(out, qr, row, column);
 235         fputc('\n', out);
 236
 237         return 0;
 238 }
 239 #endif