99 lines
2.2 KiB
C
99 lines
2.2 KiB
C
// Socket shim — rs232-compatible API over TCP sockets
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#include "sockShim.h"
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#include <sys/socket.h>
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#include <errno.h>
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#include <unistd.h>
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#include <fcntl.h>
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// ========================================================================
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// Internal state
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// ========================================================================
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#define MAX_PORTS 4
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static int sFds[MAX_PORTS] = { -1, -1, -1, -1 };
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static bool sOpen[MAX_PORTS] = { false, false, false, false };
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// ========================================================================
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// Public functions (alphabetical)
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// ========================================================================
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int rs232Close(int com) {
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if (com < 0 || com >= MAX_PORTS) {
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return RS232_ERR_INVALID_PORT;
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}
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sOpen[com] = false;
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// Socket lifecycle is managed by the caller, not the shim
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return RS232_SUCCESS;
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}
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int rs232Open(int com, int32_t bps, int dataBits, char parity, int stopBits, int handshake) {
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(void)bps;
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(void)dataBits;
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(void)parity;
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(void)stopBits;
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(void)handshake;
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if (com < 0 || com >= MAX_PORTS) {
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return RS232_ERR_INVALID_PORT;
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}
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if (sFds[com] < 0) {
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return RS232_ERR_NOT_OPEN;
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}
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sOpen[com] = true;
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return RS232_SUCCESS;
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}
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int rs232Read(int com, char *data, int len) {
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if (com < 0 || com >= MAX_PORTS || sFds[com] < 0) {
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return 0;
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}
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ssize_t n = recv(sFds[com], data, len, MSG_DONTWAIT);
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if (n <= 0) {
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return 0;
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}
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return (int)n;
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}
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int rs232Write(int com, const char *data, int len) {
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if (com < 0 || com >= MAX_PORTS || sFds[com] < 0) {
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return RS232_ERR_NOT_OPEN;
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}
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int sent = 0;
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while (sent < len) {
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ssize_t n = send(sFds[com], data + sent, len - sent, MSG_NOSIGNAL);
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if (n < 0) {
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if (errno == EINTR) {
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continue;
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}
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return RS232_ERR_NOT_OPEN;
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}
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sent += (int)n;
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}
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return RS232_SUCCESS;
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}
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void sockShimSetFd(int com, int fd) {
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if (com < 0 || com >= MAX_PORTS) {
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return;
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}
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sFds[com] = fd;
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// Set non-blocking so rs232Read returns immediately when empty
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int flags = fcntl(fd, F_GETFL, 0);
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fcntl(fd, F_SETFL, flags | O_NONBLOCK);
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}
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