initial commit

.github/workflows/build.yaml

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+name: Build App
+
+on:
+  push:
+  pull_request:
+
+env:
+  COMPILER_VERSION: arm-gnu-toolchain-13.3.rel1-x86_64-arm-none-linux-gnueabihf
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Download Toolchain
+        run: wget -O /tmp/toolchain.tar.xz https://armkeil.blob.core.windows.net/developer/Files/downloads/gnu/13.3.rel1/binrel/${{ env.COMPILER_VERSION }}.tar.xz
+
+      - name: Extract Toolchain
+        run: tar -xf /tmp/toolchain.tar.xz -C /tmp
+
+      - name: Compile App
+        run: make CROSS_COMPILE=/tmp/${{ env.COMPILER_VERSION }}/bin/arm-none-linux-gnueabihf-
+
+      - name: Upload Build output
+        uses: actions/upload-artifact@v4
+        with:
+          name: build-output
+          path: output/
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        if: github.event_name == 'push' && github.ref_type == 'tag'
+        with:
+          body: "Version ${{ github.ref_name }}"
+          files: |
+            output/*

.gitignore

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+.vscode/
+output/

Makefile

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+CROSS_COMPILE ?= 
+GCC ?= $(CROSS_COMPILE)gcc
+STRIP ?= $(CROSS_COMPILE)strip
+
+# Take git short-hash as version
+VERSION ?= $(shell git rev-parse --short HEAD)
+
+# Flags
+CFLAGS = --static -O2 -DVERSION=\"$(VERSION)\"
+
+all:
+	mkdir -p output
+	$(GCC) $(CFLAGS) -o output/t5g-at t5g.c
+	$(STRIP) output/t5g-at

README.md

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+# t5g-at-interface
+
+Quick and dirty programm for interfacing with the Modem AT Command interface on the host system of a Telekom 5G Empfänger SE.
+
+## TL;DR
+
+ToDo
+
+## How to compile
+
+```bash
+wget -O /tmp/toolchain.tar.xz https://armkeil.blob.core.windows.net/developer/Files/downloads/gnu/13.3.rel1/binrel/arm-gnu-toolchain-13.3.rel1-x86_64-arm-none-linux-gnueabihf.tar.xz
+tar -xf /tmp/toolchain.tar.xz -C /tmp
+make CROSS_COMPILE=/tmp/arm-gnu-toolchain-13.3.rel1-x86_64-arm-none-linux-gnueabihf/bin/arm-none-linux-gnueabihf-
+```
+
+## How to use
+
+```bash
+./t5g-at-interface
+```

t5g.c

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+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <termios.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#define AT_COMMAND_FILE "/dev/smd7"
+
+int open_file(char *filename, int mode) {
+	int file = open(filename, mode);
+	if (file < 0) {
+		printf("Error: Could not open file %s\n", filename);
+		return file;
+	}
+	return file;
+}
+
+int main(int argc, char *argv[]) {
+	char *file_path = NULL;
+	int file_in = 0, file_out = 0;
+	int ret = 0;
+	int i;
+	int n;
+
+	file_path = AT_COMMAND_FILE;
+	if (argc == 2) {
+		file_path = argv[1];
+	}
+
+	/* Set stdin non-blocking */
+	int flags = fcntl(STDIN_FILENO, F_GETFL, 0);
+	fcntl(STDIN_FILENO, F_SETFL, flags | O_NONBLOCK);
+
+	/* Open /dev/smd7 */
+	file_in = open_file(file_path, O_RDONLY);
+	if (file_in < 0) {
+		fprintf(stderr, "Error: Could not open AT command file\n");
+		ret = 1;
+		goto out_free;
+	}
+	flags = fcntl(file_in, F_GETFL, 0);
+	fcntl(file_in, F_SETFL, flags | O_NONBLOCK);
+
+	file_out = open_file(file_path, O_WRONLY);
+	if (file_out < 0) {
+		fprintf(stderr, "Error: Could not open AT command file\n");
+		ret = 1;
+		goto out_free;
+	}
+
+	while (1) {
+		char buf[1024];
+
+		/* Read non-blocking from file */
+		n = read(file_in, buf, sizeof(buf));
+		if (n < 0 && errno != EAGAIN) {
+			ret = 1;
+			fprintf(stderr, "Error: Could not read from AT command file\n");
+			goto out_free;
+		} else if (n > 0) {	
+			buf[n] = '\0';
+			fprintf(stdout, "%s", buf);
+		}
+
+		/* Read non-blocking from stdin */
+		n = read(STDIN_FILENO, buf, sizeof(buf));
+		if (n < 0) {
+			if (errno == EAGAIN) 
+				continue;
+			ret = 1;
+			fprintf(stderr, "Error: Could not read from AT command file\n");
+			goto out_free;
+		}
+
+		/* Print all character codes */
+		buf[n - 1] = '\r';
+		buf[n] = '\n';
+
+		//printf("Writing %d bytes to file\n", n);
+		if (write(file_out, buf, n + 1) != n + 1) {
+			fprintf(stderr, "Error: Could not write to AT command file\n");
+			ret = 1;
+			goto out_free;
+		}
+	}
+
+out_free:
+	if (file_in > 0) {
+		close(file_in);
+	}
+
+	if (file_out > 0) {
+		close(file_out);
+	}
+	return 0;
+}