fix(PICAN): align socket handling with PIEthernet patterns

- Sentinel: sock = 0 → sock = -1 (0 is stdin, valid fd)
- openDevice(): close socket on ioctl/bind failure (resource leak)
- openDevice(): set O_NONBLOCK via fcntl after socket()
- openDevice(): check setsockopt() return value
- closeDevice(): call shutdown() before close(), reset sock to -1
- readDevice() / writeDevice(): guard against sock == -1
- Add missing #include <fcntl.h>

libs/main/io_devices/pican.cpp

@@ -24,6 +24,7 @@
 #  define PIP_CAN
 #endif
 #ifdef PIP_CAN
+#  include <fcntl.h>
 #  include <linux/can.h>
 #  include <linux/can/raw.h>
 #  include <net/if.h>
@@ -49,7 +50,7 @@ PICAN::PICAN(const PIString & path, PIIODevice::DeviceMode mode): PIIODevice(pat
 	setThreadedReadBufferSize(256);
 	setPath(path);
 	can_id = 0;
-	sock   = 0;
+	sock   = -1;
 	PRIVATE->event.create();
 }
 
@@ -67,19 +68,25 @@ bool PICAN::openDevice() {
 	sock = socket(PF_CAN, SOCK_RAW, CAN_RAW);
 	if (sock < 0) {
 		piCoutObj << "Error! while opening socket";
+		sock = -1;
 		return false;
 	}
+	fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) | O_NONBLOCK);
 	ifreq ifr;
 	strcpy(ifr.ifr_name, path().dataAscii());
 	piCout << "PICAN try to get interface index...";
 	if (ioctl(sock, SIOCGIFINDEX, &ifr) < 0) {
 		piCoutObj << "Error! while determin the interface ioctl";
+		::close(sock);
+		sock = -1;
 		return false;
 	}
 	struct timeval tv;
 	tv.tv_sec  = 1;
 	tv.tv_usec = 0;
-	setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof tv);
+	if (setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, sizeof tv) < 0) {
+		piCoutObj << "Error! while setting socket receive timeout";
+	}
 	// bind socket to all CAN interface
 	sockaddr_can addr;
 	addr.can_family  = AF_CAN;
@@ -87,6 +94,8 @@ bool PICAN::openDevice() {
 	piCout << "PICAN try to bind socket to interface" << ifr.ifr_ifindex;
 	if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
 		piCoutObj << "Error! while binding socket";
+		::close(sock);
+		sock = -1;
 		return false;
 	}
 	piCout << "PICAN Open OK!";
@@ -101,7 +110,11 @@ bool PICAN::openDevice() {
 bool PICAN::closeDevice() {
 #ifdef PIP_CAN
 	interrupt();
-	if (sock > 0) ::close(sock);
+	if (sock != -1) {
+		::shutdown(sock, SHUT_RDWR);
+		::close(sock);
+		sock = -1;
+	}
 #endif
 	return true;
 }
@@ -109,6 +122,7 @@ bool PICAN::closeDevice() {
 
 ssize_t PICAN::readDevice(void * read_to, ssize_t max_size) {
 #ifdef PIP_CAN
+	if (sock == -1) return -1;
 	// piCout << "PICAN read";
 	can_frame frame;
 	ssize_t ret = 0;
@@ -127,6 +141,7 @@ ssize_t PICAN::readDevice(void * read_to, ssize_t max_size) {
 
 ssize_t PICAN::writeDevice(const void * data, ssize_t max_size) {
 #ifdef PIP_CAN
+	if (sock == -1) return -1;
 	// piCout << "PICAN write" << can_id << max_size;
 	if (max_size > 8) {
 		piCoutObj << "Can't send CAN frame bigger than 8 bytes (requested " << max_size << ")!";

libs/main/io_devices/pican.h

@@ -73,7 +73,7 @@ protected:
 
 private:
 	PRIVATE_DECLARATION(PIP_EXPORT)
-	int sock;
+	int sock = -1;
 	int can_id, readed_id;
 };