rework variable usage, real URI without referer, etc

2 files changed, 71 insertions, 39 deletions

diff --git a/Makefile b/Makefile
index 365c0e9..45238e3 100644
--- a/Makefile
+++ b/Makefile
@@ -33,6 +33,11 @@ check:
 	$(FILE) check.png | $(GREP) 'PNG image data'
 	$(ZBARIMG) --raw -q check.png | $(GREP) -e '^http://$(SERVER)/$$'
 
+	SERVER_NAME=$(SERVER) HTTP_REFERER=https://$(SERVER)/ HTTPS=on \
+		    ./cqrlogo | $(SED) '1,2d' > check.png
+	$(FILE) check.png | $(GREP) 'PNG image data'
+	$(ZBARIMG) --raw -q check.png | $(GREP) -e '^https://$(SERVER)/$$'
+
 	SERVER_NAME=$(SERVER) HTTP_REFERER=http://$(SERVER)/ \
 		QUERY_STRING='scale=0' \
 		./cqrlogo | $(SED) '1,2d' > \
@@ -101,7 +106,14 @@ check:
 		check.png
 	$(FILE) check.png | $(GREP) 'PNG image data'
 	$(ZBARIMG) --raw -q check.png | \
-		$(GREP) -e '^This QR Code has been stolen from eworm.net!$$'
+		$(GREP) -e '^This QR Code has been stolen from http://eworm.net/!$$'
+
+	SERVER_NAME=eworm.net HTTP_REFERER=https://$(SERVER)/ HTTPS=on \
+		./cqrlogo | $(SED) '1,2d' > \
+		check.png
+	$(FILE) check.png | $(GREP) 'PNG image data'
+	$(ZBARIMG) --raw -q check.png | \
+		$(GREP) -e '^This QR Code has been stolen from https://eworm.net/!$$'
 
 clean:
 	$(RM) -f *.o *~ cqrlogo
diff --git a/cqrlogo.c b/cqrlogo.c
index 927b5c3..da9a50a 100644
--- a/cqrlogo.c
+++ b/cqrlogo.c
@@ -18,7 +18,7 @@
 #include "config.h"
 
 #define URLPATTERN "^[hH][tT][tT][pP][sS]\\?://%s/"
-#define TEXTSTOLEN "This QR Code has been stolen from %s!"
+#define TEXTSTOLEN "This QR Code has been stolen from http%s://%s/!"
 
 /* a bitmap */
 struct bitmap_t {
@@ -28,7 +28,7 @@ struct bitmap_t {
 };
 
 /*** generate_png ***/
-int generate_png (struct bitmap_t *bitmap, char *http_referer) {
+int generate_png (struct bitmap_t *bitmap, const char *uri) {
 	png_structp png_ptr = NULL;
 	png_infop info_ptr = NULL;
 	png_byte ** row_pointers = NULL;
@@ -66,7 +66,7 @@ int generate_png (struct bitmap_t *bitmap, char *http_referer) {
 
 	text[2].compression = PNG_TEXT_COMPRESSION_zTXt;
 	text[2].key = "referer";
-	text[2].text = http_referer;
+	text[2].text = (char*)uri;
 
 	png_set_text(png_ptr, info_ptr, text, 3);
 	free(version);
@@ -120,7 +120,7 @@ void bitmap_free(struct bitmap_t * bitmap) {
 }
 
 /*** encode_qrcode ***/
-struct bitmap_t * encode_qrcode (char *text, unsigned int scale, unsigned int border, unsigned int level) {
+struct bitmap_t * encode_qrcode (const char *text, unsigned int scale, unsigned int border, unsigned int level) {
        QRcode *qrcode;
        struct bitmap_t *bitmap, *scaled;
        int i, j, k, l;
@@ -191,17 +191,15 @@ int get_value(const char *query_string, const char *pattern, unsigned int *value
 
 /*** main ***/
 int main(int argc, char **argv) {
-	char * http_referer, * server_name, * pattern;
+	const char * http_referer, * server_name, * query_string, * uri;
+	char * uri_server_name = NULL, * uri_png = NULL, * pattern = NULL, * stolen = NULL;
 	regex_t preg;
 	regmatch_t pmatch[1];
-	int referer = 0;
+	unsigned int https = 0;
 
 	struct bitmap_t * bitmap;
 	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"
@@ -209,9 +207,31 @@ int main(int argc, char **argv) {
 				"to send referer information.\n");
 		return EXIT_FAILURE;
 	} 
-	if ((http_referer = getenv("HTTP_REFERER")) == NULL) {
-		http_referer = server_name;
-	} else {	
+
+	/* check if we have https connection */
+	if (getenv("HTTPS") != NULL)
+		https = 1;
+
+	/* assemble uri for use when referer is missing or fails */
+	uri_server_name = malloc(10 + strlen(server_name));
+	sprintf(uri_server_name, "http%s://%s/", https ? "s" : "", server_name);
+
+	/* get query string and read settings */
+	if ((query_string = getenv("QUERY_STRING")) != NULL) {
+		/* do we have a special scale? */
+		get_value(query_string, "scale", &scale, QRCODE_SCALE, 1, QRCODE_MAX_SCALE);
+
+		/* width of the border? */
+		get_value(query_string, "border", &border, QRCODE_BORDER, 0, QRCODE_MAX_BORDER);
+
+		/* error correction level? */
+		get_value(query_string, "level", &level, QRCODE_LEVEL, 0, QR_ECLEVEL_H);
+	}
+
+	/* get http referer */
+	if ((http_referer = getenv("HTTP_REFERER")) != NULL) {
+		uri = http_referer;
+
 		/* prepare pattern matching */
 		pattern = malloc(sizeof(URLPATTERN) + strlen(server_name));
 		sprintf(pattern, URLPATTERN, server_name);
@@ -221,28 +241,24 @@ int main(int argc, char **argv) {
 		}
 
 		/* check if the QR-Code is for the correct server */
-		if ((referer = regexec(&preg, http_referer, 1, pmatch, 0)) != 0) {
-			http_referer = malloc(sizeof(TEXTSTOLEN) + strlen(server_name));
-			sprintf(http_referer, TEXTSTOLEN, server_name);
+		if (regexec(&preg, http_referer, 1, pmatch, 0) != 0) {
+			stolen = malloc(sizeof(TEXTSTOLEN) + strlen(server_name));
+			sprintf(stolen, TEXTSTOLEN, https ? "s" : "", server_name);
+			uri = stolen;
 		}
 
 		regfree(&preg);
 		free(pattern);
+	} else {
+		/* use uri assembled from server name */
+		uri = uri_server_name;
 	}
 
-	if (query_string ) {
-		/* do we have a special scale? */
-		get_value(query_string, "scale", &scale, QRCODE_SCALE, 1, QRCODE_MAX_SCALE);
-
-		/* width of the border? */
-		get_value(query_string, "border", &border, QRCODE_BORDER, 0, QRCODE_MAX_BORDER);
-
-		/* error correction level? */
-		get_value(query_string, "level", &level, QRCODE_LEVEL, 0, QR_ECLEVEL_H);
-	}
-
-	if ((bitmap = encode_qrcode(http_referer, scale, border, level)) == NULL) {
-		if ((bitmap = encode_qrcode(server_name, scale, border, level)) == NULL) {
+	/* encode the QR-Code */
+	if ((bitmap = encode_qrcode(uri, scale, border, level)) == NULL) {
+		/* uri too long? retry with uri from server name */
+		uri = uri_server_name;
+		if ((bitmap = encode_qrcode(uri, scale, border, level)) == NULL) {
 			fprintf(stderr, "Could not generate QR-Code.\n");
 			return EXIT_FAILURE;
 		}
@@ -251,23 +267,27 @@ int main(int argc, char **argv) {
 	/* 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, "...");
+	/* cut uri, text in png file may have a max length of 79 chars */
+	if (strlen(uri) > 79) {
+		uri_png = strdup(uri);
+		sprintf(uri_png + 76, "...");
+		uri = uri_png;
 	}
 
 	/* print PNG data */
-	if (generate_png(bitmap, http_referer)) {
+	if (generate_png(bitmap, uri)) {
 		fprintf(stderr, "Failed to generate PNG.\n");
 		return EXIT_FAILURE;
 	}
 
-	if (referer)
-		free(http_referer);
+
+	/* free memory we no longer need */
+	if (uri_server_name)
+		free(uri_server_name);
+	if (stolen)
+		free(stolen);
+	if (uri_png)
+		free(uri_png);
 	free(bitmap);
 
 	return EXIT_SUCCESS;