AFG/dump1090
3
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Bug Fix in modesReadFromClient()

Browse source 
The modesReadFromClient() funtion is called from modesReadFromClients(),
which in turn is called from backgroundTasks(). backgroundTasks() is
called from within the main processing loop.

However, modesReadFromClient() can and does block. It attempts to read
characters from the input stream, and loops whilst there was no error.
This stalls the main RTL processing loop until an error occurs. In order
to support simultaneous local reception (via our RTL dongle) and remote
forwarding (data received from the interweb) we cannot allow this
internet read to stall.

To fix this, in modesReadFromClient() attempt to read a buffer of data
(currently 0x400 bytes). If we get a full buffer of bytes, then process
them, and attempt to read another full buffer. Keep doing thios untill
we read only a partial buffer (less than 0x400 bytes). Process the
partial buffer bytes and return.

This allows us to occasionally process data that is arriving from the
internet (which is buffered anyway in the TCP stack), without blocking
local RTL dongle decoding.
This commit is contained in:
Malcolm Robb 2013-09-20 16:48:15 +01:00
parent 52ac50b018
commit 7ea2e8fdef
3 changed files with 59 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

7
dump1090.h
View file

@ -159,7 +159,7 @@
#define MODES_INTERACTIVE_DELETE_TTL 300 // Delete from the list after 300 seconds
#define MODES_INTERACTIVE_DISPLAY_TTL 60 // Delete from display after 60 seconds
#define MODES_NET_MAX_FD 1024
#define MODES_NET_MAX_FD 1024
#define MODES_NET_INPUT_RAW_PORT 30001
#define MODES_NET_OUTPUT_RAW_PORT 30002
#define MODES_NET_OUTPUT_SBS_PORT 30003
@ -181,8 +181,8 @@
struct client {
int fd; // File descriptor
int service; // TCP port the client is connected to
char buf[MODES_CLIENT_BUF_SIZE+1]; // Read buffer
int buflen; // Amount of data on buffer
char buf[MODES_CLIENT_BUF_SIZE+1]; // Read buffer
};
// Structure used to describe an aircraft in iteractive mode
@ -405,6 +405,8 @@ void modesInitErrorInfo ();
struct aircraft* interactiveReceiveData(struct modesMessage *mm);
void interactiveShowData(void);
void interactiveRemoveStaleAircrafts(void);
int decodeBinMessage (struct client *c, char *p);
//
// Functions exported from net_io.c
//
@ -412,6 +414,7 @@ void modesInitNet (void);
void modesReadFromClients (void);
void modesSendAllClients (int service, void *msg, int len);
void modesQueueOutput (struct modesMessage *mm);
void modesReadFromClient(struct client *c, char *sep, int(*handler)(struct client *, char *));
#ifdef __cplusplus
}