ssize_t py_recv(int fd, void *buf, size_t len, int *cdata)
{
struct msghdr msg = {0};
struct iovec iov = {0};
size_t cmsglen = CMSG_SPACE(sizeof(int));
char control[CMSG_SPACE(sizeof(int))];
struct cmsghdr *cmsg;
ssize_t ret;
iov.iov_base = buf;
iov.iov_len = len;
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
if (cdata != NULL) {
msg.msg_control = control;
msg.msg_controllen = cmsglen;
}
ret = recvmsg(fd, &msg, 0);
if (ret == -1 || cdata == NULL) {
return ret;
}
cmsg = CMSG_FIRSTHDR(&msg);
if (cmsg == NULL || cmsg->cmsg_len != CMSG_LEN(sizeof(int))
|| cmsg->cmsg_level != SOL_SOCKET
|| cmsg->cmsg_type != SCM_RIGHTS) {
*cdata = -1;
} else {
*cdata = get_unaligned_int(CMSG_DATA(cmsg));
}
return ret;
}
/* receives a fd and data_len data
* params: unix_socket
* data
* data_len
* fd - will be set to the passed fd value or -1 if no fd
* was passed
* flags - 0, MSG_DONTWAIT, MSG_WAITALL; same as recv_all flags
* returns: bytes read on success, -1 on error (and sets errno) */
int receive_fd(int unix_socket, void* data, int data_len, int* fd, int flags)
{
struct msghdr msg;
struct iovec iov[1];
int new_fd;
int ret;
int n;
#ifdef HAVE_MSGHDR_MSG_CONTROL
struct cmsghdr* cmsg;
union{
struct cmsghdr cm;
char control[CMSG_SPACE(sizeof(new_fd))];
}control_un;
msg.msg_control=control_un.control;
msg.msg_controllen=sizeof(control_un.control);
#else
msg.msg_accrights=(caddr_t) &new_fd;
msg.msg_accrightslen=sizeof(int);
#endif
msg.msg_name=0;
msg.msg_namelen=0;
iov[0].iov_base=data;
iov[0].iov_len=data_len;
msg.msg_iov=iov;
msg.msg_iovlen=1;
again:
ret=recvmsg(unix_socket, &msg, flags);
if (ret<0){
if (errno==EINTR) goto again;
if ((errno==EAGAIN)||(errno==EWOULDBLOCK)) goto error;
LM_CRIT("recvmsg on %d failed: %s\n", unix_socket, strerror(errno));
goto error;
}
if (ret==0){
/* EOF */
LM_CRIT("EOF on %d\n", unix_socket);
goto error;
}
if (ret<data_len){
LM_WARN("too few bytes read (%d from %d) trying to fix...\n",
ret, data_len);
/* blocking recv_all */
n=recv_all(unix_socket, (char*)data+ret, data_len-ret, MSG_WAITALL);
if (n>=0) ret+=n;
else{
ret=n;
goto error;
}
}
#ifdef HAVE_MSGHDR_MSG_CONTROL
cmsg=CMSG_FIRSTHDR(&msg);
if ((cmsg!=0) && (cmsg->cmsg_len==CMSG_LEN(sizeof(new_fd)))){
if (cmsg->cmsg_type!= SCM_RIGHTS){
LM_ERR("msg control type != SCM_RIGHTS\n");
ret=-1;
goto error;
}
if (cmsg->cmsg_level!= SOL_SOCKET){
LM_ERR("msg level != SOL_SOCKET\n");
ret=-1;
goto error;
}
*fd = get_unaligned_int(CMSG_DATA(cmsg));
}else{
/*
LM_ERR("no descriptor passed, cmsg=%p,len=%d\n",
cmsg, (unsigned)cmsg->cmsg_len); */
*fd=-1;
/* it's not really an error */
}
#else
if (msg.msg_accrightslen==sizeof(int)){
*fd=new_fd;
}else{
/*LM_ERR("no descriptor passed, accrightslen=%d\n",
msg.msg_accrightslen); */
*fd=-1;
}
#endif
error:
return ret;
}
