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/*
* (C) 2013 by Christian Hesse <mail@eworm.de>
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <regex.h>
#include <png.h>
#include <zlib.h>
#include <qrencode.h>
#include "config.h"
/* a bitmap */
struct bitmap_t {
int width;
int height;
uint8_t *pixel;
};
/*** generate_png ***/
int generate_png (struct bitmap_t *bitmap, char *http_referer) {
png_structp png_ptr = NULL;
png_infop info_ptr = NULL;
png_byte ** row_pointers = NULL;
int x, y, depth = 8;
if ((png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL)) == NULL)
return 1;
if ((info_ptr = png_create_info_struct (png_ptr)) == NULL ||
(setjmp (png_jmpbuf (png_ptr)))) {
png_destroy_write_struct (&png_ptr, &info_ptr);
return 1;
}
png_set_IHDR (png_ptr, info_ptr, bitmap->width, bitmap->height, depth,
PNG_COLOR_TYPE_GRAY, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
#ifdef PNG_TEXT_SUPPORTED
png_text text[3];
char *version;
const char *v_libpng = png_libpng_ver, *v_zlib = zlib_version;
version = malloc(18 + strlen(VERSION) + strlen(v_libpng) + strlen(v_zlib));
sprintf(version, VERSION " (libpng %s, zlib %s)", png_libpng_ver, zlib_version);
text[0].compression = PNG_TEXT_COMPRESSION_zTXt;
text[0].key = "comment";
text[0].text = "QR-Code created by cqrlogo - https://github.com/eworm-de/cqrlogo";
text[1].compression = PNG_TEXT_COMPRESSION_zTXt;
text[1].key = "version";
text[1].text = version;
text[2].compression = PNG_TEXT_COMPRESSION_zTXt;
text[2].key = "referer";
text[2].text = http_referer;
png_set_text(png_ptr, info_ptr, text, 3);
free(version);
#endif
row_pointers = png_malloc (png_ptr, bitmap->height * sizeof (png_byte *));
for (y = 0; y < bitmap->height; ++y) {
png_byte *row = png_malloc (png_ptr, sizeof (uint8_t) * bitmap->width);
row_pointers[y] = row;
for (x = 0; x < bitmap->width; ++x) {
*row++ = bitmap->pixel[y * bitmap->width + x];
}
}
png_init_io (png_ptr, stdout);
png_set_rows (png_ptr, info_ptr, row_pointers);
png_write_png (png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
for (y = 0; y < bitmap->height; y++) {
png_free (png_ptr, row_pointers[y]);
}
png_free (png_ptr, row_pointers);
return 0;
}
/*** bitmap_new ***/
struct bitmap_t * bitmap_new(int width, int height) {
struct bitmap_t *bitmap;
if ((bitmap = malloc(sizeof(struct bitmap_t))) == NULL)
return NULL;
bitmap->width = width;
bitmap->height = height;
if ((bitmap->pixel = malloc(width * height * sizeof(uint8_t))) == NULL) {
free(bitmap);
return NULL;
}
/* initialize with white */
memset(bitmap->pixel, 0xff, width * height);
return bitmap;
}
/*** bitmap_free ***/
void bitmap_free(struct bitmap_t * bitmap) {
free(bitmap->pixel);
free(bitmap);
}
/*** encode_qrcode ***/
struct bitmap_t * encode_qrcode (char *text, unsigned int scale, unsigned int border, unsigned int level) {
QRcode *qrcode;
struct bitmap_t *bitmap, *scaled;
int i, j, k, l;
unsigned char *data;
qrcode = QRcode_encodeData(strlen(text), (unsigned char *)text, 0, level);
if (qrcode == NULL)
return NULL;
data = qrcode->data;
/* wirte QR code to bitmap */
if ((bitmap = bitmap_new(qrcode->width + border * 2, qrcode->width + border * 2)) == NULL)
return NULL;
for (i = border; i < qrcode->width + border; i++)
for (j = border; j < qrcode->width + border; j++) {
bitmap->pixel[i * (qrcode->width + border * 2) + j] = !(*data & 0x1) * 0xff;
data++;
}
QRcode_free(qrcode);
if (scale == 1)
return bitmap;
/* scale bitmap */
if ((scaled = bitmap_new(bitmap->width * scale, bitmap->height * scale)) == NULL)
return NULL;
for (i = 0; i < bitmap->height; i++)
for (j = 0; j < bitmap->width; j++)
for (k = 0; k < scale; k++)
for (l = 0; l < scale; l++)
scaled->pixel[i * bitmap->width * scale * scale + k * bitmap->width * scale + j * scale + l] =
bitmap->pixel[i * bitmap->width + j];
bitmap_free(bitmap);
return scaled;
}
int main(int argc, char **argv) {
char * http_referer, * server_name, * pattern;
regex_t preg;
regmatch_t pmatch[1];
int referer = 0;
struct bitmap_t * bitmap;
char *match = NULL;
unsigned int scale = QRCODE_SCALE, border = QRCODE_BORDER, level = QRCODE_LEVEL;
/* get query string for later use */
char * query_string = getenv("QUERY_STRING");
/* check if we have environment variables from CGI */
if ((server_name = getenv("SERVER_NAME")) == NULL) {
fprintf(stderr, "This is a CGI executable. Running without a web service is not supported.\n"
"Note that SERVER_NAME needs to be defined, for full features the client has\n"
"to send referer information.\n");
return EXIT_FAILURE;
}
if ((http_referer = getenv("HTTP_REFERER")) == NULL) {
http_referer = server_name;
} else {
/* prepare pattern matching */
pattern = malloc(28 + strlen(server_name));
sprintf(pattern, "^[hH][tT][tT][pP][sS]\\?://%s/", server_name);
if (regcomp(&preg, pattern, 0) != 0) {
fprintf(stderr, "regcomp() failed, returning nonzero\n");
return EXIT_FAILURE;
}
/* check if the QR-Code is for the correct server */
if ((referer = regexec(&preg, http_referer, 1, pmatch, 0)) != 0) {
http_referer = malloc(44 + strlen(server_name));
sprintf(http_referer, "This QR Code has been stolen from %s!", server_name);
}
regfree(&preg);
free(pattern);
}
if (query_string ) {
/* do we have a special scale? */
if ((match = strstr(query_string, "scale=")) != NULL)
if ((sscanf(match, "scale=%u", &scale)) > 0)
if (scale < 1 || scale > QRCODE_MAX_SCALE)
scale = QRCODE_SCALE;
/* width of the border? */
if ((match = strstr(query_string, "border=")) != NULL)
if ((sscanf(match, "border=%u", &border)) > 0)
if (border > QRCODE_MAX_BORDER)
border = QRCODE_BORDER;
/* error correction level? */
if ((match = strstr(query_string, "level=")) != NULL)
if ((sscanf(match, "level=%u", &level)) > 0)
if (level > QR_ECLEVEL_H)
level = QRCODE_LEVEL;
}
if ((bitmap = encode_qrcode(http_referer, scale, border, level)) == NULL) {
if ((bitmap = encode_qrcode(server_name, scale, border, level)) == NULL) {
fprintf(stderr, "Could not generate QR-Code.\n");
return EXIT_FAILURE;
}
}
/* print HTTP header */
printf("Content-Type: image/png\n\n");
/* cut http_referer, text in png file may have a max length of 79 chars */
if (strlen(http_referer) > 79) {
if (!referer) {
http_referer = strdup(http_referer);
referer++;
}
sprintf(http_referer + 76, "...");
}
/* print PNG data */
if (generate_png(bitmap, http_referer)) {
fprintf(stderr, "Failed to generate PNG.\n");
return EXIT_FAILURE;
}
if (referer)
free(http_referer);
free(bitmap);
return EXIT_SUCCESS;
}
// vim: set syntax=c:
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