added basic startup checks, reusable functions, ANSI escape chars definition

.gitignore

@@ -52,3 +52,7 @@ Module.symvers
 Mkfile.old
 dkms.conf
 
+# Custom
+sentinel
+.vscode
+

main.c

@@ -0,0 +1,124 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ncurses.h>
+
+/* define ANSI escape chars */
+#define RESET "\033[0m"
+#define BOLD "\033[1m"
+#define UNDERLINE "\033[4m"
+#define BLINK "\033[5m"
+#define REVERSED "\033[7m"
+#define BLACK "\033[30m"
+#define RED "\033[31m"
+#define GREEN "\033[32m"
+#define YELLOW "\033[33m"
+#define BLUE "\033[34m"
+#define MAGENTA "\033[35m"
+#define CYAN "\033[36m"
+#define WHITE "\033[37m"
+#define BG_BLACK "\033[40m"
+#define BG_RED "\033[41m"
+#define BG_GREEN "\033[42m"
+#define BG_YELLOW "\033[43m"
+#define BG_BLUE "\033[44m"
+#define BG_MAGENTA "\033[45m"
+#define BG_CYAN "\033[46m"
+#define BG_WHITE "\033[47m"
+
+/* declare global constants */
+
+
+/* declare reusable functions */
+
+/* read out shell command output */
+char* readout(const char* command, char* buffer, size_t size) {
+    FILE *fp = popen(command, "r");
+    if (fp == NULL) {
+        perror("popen");
+        exit(EXIT_FAILURE);
+    }
+    if (fgets(buffer, size, fp) == NULL) {
+        perror("fgets");
+        pclose(fp);
+        exit(EXIT_FAILURE);
+    }
+    pclose(fp);
+    /* remove the newline character at the end of the buffer */
+    buffer[strcspn(buffer, "\n")] = 0;
+    return buffer;
+}
+
+void startup_screen() {
+    printf("\n\n");
+    printf(CYAN"                             █████     ███                      ████ \n");
+    printf("                             ░░███     ░░░                      ░░███ \n");
+    printf("  █████   ██████  ████████   ███████   ████  ████████    ██████  ░███ \n");
+    printf(" ███░░   ███░░███░░███░░███ ░░░███░   ░░███ ░░███░░███  ███░░███ ░███ \n");
+    printf("░░█████ ░███████  ░███ ░███   ░███     ░███  ░███ ░███ ░███████  ░███ \n");
+    printf(" ░░░░███░███░░░   ░███ ░███   ░███ ███ ░███  ░███ ░███ ░███░░░   ░███ \n");
+    printf(" ██████ ░░██████  ████ █████  ░░█████  █████ ████ █████░░██████  █████\n");
+    printf("░░░░░░   ░░░░░░  ░░░░ ░░░░░    ░░░░░  ░░░░░ ░░░░ ░░░░░  ░░░░░░  ░░░░░ \n\n");
+    printf("        v0.0.1\n" RESET);
+}
+
+/* declare functions for startup checks */
+void util_check() {
+    printf("curl: ");
+    if (system("curl --version > /dev/null 2>&1") == 0) {
+        printf(GREEN"OK\n"RESET);
+    } else {
+        printf(RED"FAIL\n"RESET);
+    }
+    printf("rtl-sdr: ");
+    if (system("ls /usr/bin/rtl_sdr > /dev/null 2>&1") == 0) {
+        printf(GREEN"OK\n"RESET);
+    } else {
+        printf(RED"FAIL\n"RESET);
+    }
+}
+
+
+/* making sure program has everything it needs to run, more checks will be introduced as capabilities are added */
+void startup_checks() {
+    printf("######################################################################\n");
+    printf(MAGENTA"STARTUP CHECKS\n"RESET);
+    printf("----------------------------------------------------------------------\n");
+    printf(MAGENTA"SYSTEM STATUS\n\n"RESET);
+    printf("date: %s\n", readout("date \"+%D\"", (char[100]){0}, 100));
+    printf("time: %s\n", readout("date \"+%T\"", (char[100]){0}, 100));
+    /* internet connectivity check */
+    int status = system("ping -c 1 fsf.org > /dev/null 2>&1");
+    if (status == 0) {
+        printf("internet connectivity status: ");
+        printf(GREEN"online\n"RESET);
+    } else {
+       printf("internet connectivity status: ");
+       printf(RED"offline\n"RESET);
+       printf(RED"internet-dependent capabilities will be unavailable!"RESET);
+    }
+    printf("----------------------------------------------------------------------\n");
+    /* utilities presence check */
+    printf(MAGENTA"UTILITIES\n\n"RESET);
+    util_check();
+    printf("----------------------------------------------------------------------\n");
+    printf(MAGENTA"all checks finished!\n"RESET);
+    printf("######################################################################\n");
+}
+
+/* define functions for dashboard - WIP */
+
+/*
+void start_dashboard() {
+    initscr();
+    cbreak();
+    noecho();
+}
+*/
+
+
+int main() {
+    startup_screen();
+    startup_checks();
+    return 0;
+}