Silence a pile of 'cppcheck' warnings.

...And fix a legitimate bug in the process!

Makefile

@@ -21,6 +21,9 @@ $(EXEC_NAME): $(SOURCES) $(DEPS)
 $(BACKENDS): $(EXEC_NAME)
 	ln -sf $(EXEC_NAME) $@
 
+cppcheck:
+	cppcheck -q -v --std=c99 --enable=all -DURI_PREFIX=\"$(BACKEND_NAME)\" $(SOURCES) 
+
 install:	
 	install -o root -m 700 $(EXEC_NAME) $(CUPS_BACKEND_DIR)/$(BACKEND_NAME)
 	mkdir -p $(CUPS_DATA_DIR)/usb

backend_canonselphy.c

@@ -574,7 +574,7 @@ static int canonselphy_early_parse(void *vctx, int data_fd)
 
 	/* Figure out printer this file is intended for */
 	i = read(data_fd, ctx->buffer, MAX_HEADER);
-	if (i < 0 || i != MAX_HEADER) {
+	if (i != MAX_HEADER) {
 		if (i == 0)
 			return -1;
 		ERROR("Read failed (%d/%d/%d)\n", 

backend_common.c

@@ -97,7 +97,7 @@ int read_data(struct libusb_device_handle *dev, uint8_t endp,
 	int ret;
 
 	/* Clear buffer */
-	memset(buf, buflen, 0);
+	memset(buf, 0, buflen);
 
 	ret = libusb_bulk_transfer(dev, endp,
 				   buf,
@@ -267,7 +267,7 @@ static int print_scan_output(struct libusb_device *device,
 		/* XXX this is ... a cut-n-paste hack */
 
 		uint8_t endp_up, endp_down;
-		int i, iface = 0;
+		int iface = 0;
 		struct libusb_config_descriptor *config;
 
 		if (libusb_kernel_driver_active(dev, iface))
@@ -276,6 +276,7 @@ static int print_scan_output(struct libusb_device *device,
 		/* If we fail to claim the printer, it's already in use
 		   so we should just skip over it... */
 		if (!libusb_claim_interface(dev, iface)) {
+			int i;
 			libusb_get_active_config_descriptor(device, &config);
 			for (i = 0 ; i < config->interface[0].altsetting[0].bNumEndpoints ; i++) {
 				if ((config->interface[0].altsetting[0].endpoint[i].bmAttributes & 3) == LIBUSB_TRANSFER_TYPE_BULK) {
@@ -429,13 +430,13 @@ static int find_and_enumerate(struct libusb_context *ctx,
 static struct dyesub_backend *find_backend(char *uri_prefix)
 {
 	int i;
-	struct dyesub_backend *backend;
+	
 
 	if (!uri_prefix)
 		return NULL;
 
 	for (i = 0; ; i++) {
-		backend = backends[i];
+		struct dyesub_backend *backend = backends[i];
 		if (!backend)
 			return NULL;
 		if (!strcmp(uri_prefix, backend->uri_prefix))
@@ -471,7 +472,6 @@ static void print_help(char *argv0, struct dyesub_backend *backend)
 {
 	struct libusb_context *ctx = NULL;
 	struct libusb_device **list = NULL;
-	int i;
 
 	char *ptr = strrchr(argv0, '/');
 	if (ptr)
@@ -483,6 +483,7 @@ static void print_help(char *argv0, struct dyesub_backend *backend)
 		backend = find_backend(ptr);
 	
 	if (!backend) {
+		int i;
 		DEBUG("CUPS Usage:\n");
 		DEBUG("\tDEVICE_URI=someuri %s job user title num-copies options [ filename ]\n", URI_PREFIX);
 		DEBUG("\n");

backend_dnpds40.c

@@ -86,13 +86,13 @@ struct dnpds40_cmd {
 
 static void dnpds40_build_cmd(struct dnpds40_cmd *cmd, char *arg1, char *arg2, uint32_t arg3_len)
 {
-	char buf[9];
 	memset(cmd, 0x20, sizeof(*cmd));
 	cmd->esc = 0x1b;
 	cmd->p = 0x50;
 	memcpy(cmd->arg1, arg1, min(strlen(arg1), sizeof(cmd->arg1)));
 	memcpy(cmd->arg2, arg2, min(strlen(arg2), sizeof(cmd->arg2)));
 	if (arg3_len) {
+		char buf[9];
 		snprintf(buf, sizeof(buf), "%08d", arg3_len);
 		memcpy(cmd->arg3, buf, 8);
 	}
@@ -318,7 +318,7 @@ static void dnpds40_teardown(void *vctx) {
 
 static int dnpds40_read_parse(void *vctx, int data_fd) {
 	struct dnpds40_ctx *ctx = vctx;
-	int i, j, run = 1;
+	int run = 1;
 	char buf[9] = { 0 };
 
 	uint32_t matte = 0, multicut = 0, dpi = 0;
@@ -348,7 +348,7 @@ static int dnpds40_read_parse(void *vctx, int data_fd) {
 	}
 
 	while (run) {
-		int remain;
+		int remain, i, j;
 		/* Read in command header */
 		i = read(data_fd, ctx->databuf + ctx->datalen, 
 			 sizeof(struct dnpds40_cmd));

backend_mitsu70x.c

@@ -326,7 +326,6 @@ static int mitsu70x_get_status(struct mitsu70x_ctx *ctx)
 	uint8_t cmdbuf[CMDBUF_LEN];
 	struct mitsu70x_status_resp resp;
 	int num, ret;
-	unsigned int i;
 
 	/* Send Printer Query */
 	memset(cmdbuf, 0, CMDBUF_LEN);
@@ -349,6 +348,8 @@ static int mitsu70x_get_status(struct mitsu70x_ctx *ctx)
 	}
 
 	if (dyesub_debug) {
+		unsigned int i;
+
 		DEBUG("Status Dump:\n");
 		for (i = 0 ; i < sizeof(resp.unk) ; i++) {
 			DEBUG2("%02x ", resp.unk[i]);

backend_sonyupdr150.c

@@ -82,7 +82,7 @@ static void updr150_teardown(void *vctx) {
 #define MAX_PRINTJOB_LEN 16736455
 static int updr150_read_parse(void *vctx, int data_fd) {
 	struct updr150_ctx *ctx = vctx;
-	int i, len, run = 1;
+	int len, run = 1;
 
 	if (!ctx)
 		return 1;
@@ -100,6 +100,7 @@ static int updr150_read_parse(void *vctx, int data_fd) {
 	}
 
 	while(run) {
+		int i;
 		int keep = 0;
 		i = read(data_fd, ctx->databuf + ctx->datalen, 4);
 		if (i < 0)