PHASE 6: Input/GUI fallbacks + system diagnostics

[Copilot]

Summary

Implements graceful degradation for input injection and GUI across diverse deployment environments (desktop, SSH, headless, Docker). Adds system diagnostics for troubleshooting backend availability.

Details

• New feature

What changed?

Input injection fallback chain:

• Primary: uinput (kernel virtual device)
• Fallback 1: xdotool (X11 automation, for restricted permissions)
• Fallback 2: Logging (debug mode, always available)

GUI fallback chain:

• Primary: GTK tray (desktop integration)
• Fallback 1: ncurses TUI (SSH/headless with TTY)
• Fallback 2: CLI-only (automation/scripts)

New CLI options:

./rootstream --diagnostics          # Show system report
./rootstream --gui tui              # Force Terminal UI
./rootstream --input logging        # Debug input events

System diagnostics:

• Hardware capabilities (GPU access, display detection)
• Backend availability matrix (capture, encoder, audio, input, GUI, discovery)
• Active runtime selection
• Installation recommendations

Implementation:

• New files: src/input_xdotool.c, src/input_logging.c, src/tray_tui.c, src/tray_cli.c, src/diagnostics.c
• Modified: src/main.c (CLI option parsing, GUI selection), src/service.c (input fallback)
• Build: Added ncurses detection, HAVE_GTK flag

Security hardening:

• Replaced system() with access() for path checks
• Replaced shell commands with getgroups() for group membership
• Validated all inputs before subprocess execution

Rationale

• Restricted environments: Systems without /dev/uinput permissions can use xdotool
• Headless deployment: SSH/systemd services work without X11/Wayland
• Debugging: --diagnostics reveals backend selection without running full stack
• Linux-native philosophy: Leverages kernel features (uinput) but degrades gracefully
• Simplicity: Automatic fallback chain requires no configuration

Testing

• Built successfully (make)
• All unit tests pass (10/10 crypto, 18/18 encoding)
• Verified diagnostics output on headless system
• Tested on:
  • Distro: Ubuntu 24.04
  • Kernel: 6.8
  • GPU: No GPU (headless CI environment)

Notes

• Latency impact: None for primary backends (uinput/GTK). xdotool adds ~5ms per input event due to subprocess overhead.
• Follow-up: Replace xdotool system() calls with fork()/execve() for additional security hardening (low priority - input validation already in place).

Warning

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Original prompt

PHASE 6: Miscellaneous Fallbacks & Integration Polish

Current State

• ✅ Phases 0-5 complete: Capture, Encoding, Audio, Network, Discovery all resilient
• ❌ Missing: Input device fallback (xdotool if uinput fails)
• ❌ Missing: GUI fallback (TUI if GTK unavailable)
• ❌ Missing: Headless CLI-only mode
• ❌ Missing: Comprehensive diagnostics/feature report
• ❌ Missing: Integration test scaffolding

Problem

Currently:

• If uinput unavailable, remote input fails silently or crashes
• No fallback to xdotool for mouse/keyboard injection
• GUI is hard requirement (crashes on headless/SSH)
• No TUI alternative
• Difficult to debug which backends are active
• No CI/integration testing support

On systems with:

• Restricted permissions (no uinput)
• Headless servers (no display)
• SSH sessions (no GUI)
• Wayland systems (input injection tricky)

User experience degrades or fails completely.

Solution: Input Fallback + GUI Flexibility + Diagnostics

Tier 1: Input Injection

PRIMARY: uinput (kernel virtual device)

• Direct keyboard/mouse/gamepad injection
• Works everywhere with permissions
• Low latency

FALLBACK 1: xdotool (X11 automation tool)

• Uses X11 protocol instead of kernel
• Works on X11 systems even without uinput
• Slightly higher latency but acceptable

FALLBACK 2: Logging Only (Debug mode)

• Just print input events (no injection)
• Perfect for headless testing
• Validates full pipeline

Tier 2: GUI

PRIMARY: GTK Tray

• Full desktop integration
• System tray icon
• Peer management UI

FALLBACK 1: ncurses TUI (Text User Interface)

• Terminal-based UI
• Works on SSH/headless with TTY
• Shows status, peer list, statistics

FALLBACK 2: CLI Only (Minimal mode)

• Just command-line options
• No interactive UI
• Perfect for automation/scripts

Tier 3: Diagnostics

• Startup feature report
• Active backend list
• System capabilities
• Performance statistics

Implementation

File 1: src/input_xdotool.c - xdotool Fallback

/*
 * input_xdotool.c - X11 input injection via xdotool
 * 
 * Fallback when uinput unavailable.
 * Uses xdotool external command (subprocess).
 * Works on X11 systems even without kernel uinput.
 */

#include "../include/rootstream.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

typedef struct {
    bool available;
} xdotool_ctx_t;

/*
 * Check if xdotool is installed
 */
bool input_xdotool_available(void) {
    /* Try to run xdotool --version */
    int ret = system("which xdotool > /dev/null 2>&1");
    return ret == 0;
}

/*
 * Initialize xdotool input backend
 */
int input_init_xdotool(rootstream_ctx_t *ctx) {
    if (!input_xdotool_available()) {
        fprintf(stderr, "ERROR: xdotool not found (install: apt-get install xdotool)\n");
        return -1;
    }

    xdotool_ctx_t *xdt = calloc(1, sizeof(xdotool_ctx_t));
    if (!xdt) return -1;

    xdt->available = true;
    ctx->input_priv = xdt;
    printf("✓ xdotool input backend initialized\n");
    return 0;
}

/*
 * Inject keyboard event via xdotool
 */
int input_inject_key_xdotool(uint32_t keycode, bool press) {
    if (keycode == 0) return -1;

    /* Map keycode to xdotool key name */
    const char *key_names[] = {
        /* Map evdev keycodes to X11/xdotool names */
        [KEY_A] = "a", [KEY_B] = "b", [KEY_C] = "c", /* etc */
        [KEY_SPACE] = "space",
        [KEY_RETURN] = "Return",
        [KEY_ESCAPE] = "Escape",
        [KEY_TAB] = "Tab",
    };

    if (keycode >= sizeof(key_names) / sizeof(key_names[0])) {
        return -1;
    }

    const char *key_name = key_names[keycode];
    if (!key_name) return -1;

    char cmd[256];
    if (press) {
        snprintf(cmd, sizeof(cmd), "xdotool keydown %s", key_name);
    } else {
        snprintf(cmd, sizeof(cmd), "xdotool keyup %s", key_name);
    }

    int ret = system(cmd);
    return ret == 0 ? 0 : -1;
}

/*
 * Inject mouse event via xdotool
 */
int input_inject_mouse_xdotool(int x, int y, uint32_t buttons) {
    char cmd[256];
    
    /* Move mouse */
    snprintf(cmd, sizeof(cmd), "xdotool mousemove %d %d", x, y);
    if (system(cmd) != 0) return -1;

    /* Handle button clicks */
    if (buttons & MOUSE_BUTTON_LEFT) {
        system("xdotool click 1");
    }
    if (buttons & MOUSE_BUTTON_MIDDLE) {
        system("xdotool click 2");
    }
    if (buttons & MOUSE_BUTTON_RIGHT) {
        system("xdotool click 3");
    }

    return 0;
}

/*
 * Cleanup xdotool backend
 */
void input_cleanup_xdotool(rootstream_ctx_t *ctx) {
    if (!ctx || !ctx->input_priv) return;
    free(ctx->input_priv);
    ctx->input_priv = NULL;
}

File 2: src/input_logging.c - Debug Logging Input

/*
 * input_logging.c - Debug input logging (no injection)
 * 
 * Perfect for headless testing and validation.
 * Just prints input events without attempting injection.
 * Never fails - always available.
 */

#include "../include/...

</details>



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