Add lfbview tool: LFB viewer using SDL2

In theory, should work under X and Wayland.
It won't work under Windows though because of used system calls.

.gitignore

@@ -16,6 +16,7 @@ tools/gensamehash
 tools/mksamehash
 tools/mkfilepattern
 tools/lfbviewx
+tools/lfbview
 tools/randdir
 *.qcow2
 *.img

README

@@ -125,23 +125,35 @@ To load apps at 0 address.
 Links & Acknowledgements
 ------------------------
 
-[1] Filesystem in Userspace library
+[ 1] Filesystem in Userspace
+     https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/fuse
+
+[ 2] Filesystem in Userspace library
      https://github.com/libfuse/libfuse
 
-[2] LodePNG by Lode Vandevenne
+[ 3] LodePNG by Lode Vandevenne
      https://lodev.org/lodepng/
 
-[3] Optparse by Christopher Wellons
+[ 4] Optparse by Christopher Wellons
      https://github.com/skeeto/optparse
 
-[4] Universal TUN/TAP device driver by Maxim Krasnyansky and others
+[ 5] Universal TUN/TAP device driver by Maxim Krasnyansky and others
      https://www.kernel.org/doc/html/v5.12/networking/tuntap.html
 
-[5] Bestline by Justine Tunney
+[ 6] Bestline by Justine Tunney
      https://github.com/jart/bestline
 
-[6] Miniz by Rich Geldreich
+[ 7] Miniz by Rich Geldreich
      https://github.com/richgel999/miniz
 
-[7] QEMU by Fabrice Bellard and others
-    https://www.qemu.org
+[ 8] qemu-nbd by Anthony Liguori and others
+     https://www.qemu.org/docs/master/tools/qemu-nbd.html
+
+[ 9] io_uring by Jens Axboe and others
+     https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/io_uring
+
+[10] io_uring-by-example by Shuveb Hussain
+     https://github.com/shuveb/io_uring-by-example
+
+[11] Simple DirectMedia Layer library aka SDL2
+     https://libsdl.org

tools/lfbview.c

@@ -0,0 +1,80 @@
+/*
+    SPDX-License-Identifier: GPL-2.0-or-later
+
+    UMKa - User-Mode KolibriOS developer tools
+    lfbview - KolibriOS framebuffer viewer via SDL2
+
+    Copyright (C) 2023  Ivan Baravy <dunkaist@gmail.com>
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/uio.h>
+#include <unistd.h>
+#include <SDL2/SDL.h>
+
+int
+main(int argc, char *argv[]) {
+    const char *usage = "usage: lfbview <pid> <address> <width> <height>";
+    if (argc != 5) {
+        puts(usage);
+        exit(1);
+    }
+    int depth = 32;
+    int umka_pid = strtol(argv[1], NULL, 0);
+    uintptr_t umka_lfb_addr = strtol(argv[2], NULL, 0);
+    size_t lfb_width = strtoul(argv[3], NULL, 0);
+    size_t lfb_height = strtoul(argv[4], NULL, 0);
+
+    if(SDL_Init(SDL_INIT_VIDEO) < 0)
+    {
+        fprintf(stderr, "Failed to initialize the SDL2 library\n");
+        return -1;
+    }
+
+    SDL_Window *window = SDL_CreateWindow("LFB Viewer SDL2",
+                                          SDL_WINDOWPOS_CENTERED,
+                                          SDL_WINDOWPOS_CENTERED,
+                                          400, 300,
+                                          0);
+
+    if(!window)
+    {
+        fprintf(stderr, "Failed to create window\n");
+        return -1;
+    }
+
+    SDL_Surface *window_surface = SDL_GetWindowSurface(window);
+
+    if(!window_surface)
+    {
+        fprintf(stderr, "Failed to get the surface from the window\n");
+        return -1;
+    }
+
+    uint32_t *lfb = (uint32_t*)malloc(lfb_width*lfb_height*sizeof(uint32_t));
+
+    struct iovec remote = {.iov_base = (void*)umka_lfb_addr,
+                           .iov_len = lfb_width*lfb_height*4};
+    struct iovec local = {.iov_base = lfb,
+                          .iov_len = lfb_width*lfb_height*4};
+
+
+    uint32_t *p = window_surface->pixels;
+    while (1) {
+        process_vm_readv(umka_pid, &local, 1, &remote, 1, 0);
+        memcpy(window_surface->pixels, lfb, 400*300*4);
+        SDL_LockSurface(window_surface);
+        for (size_t y = 0; y < window_surface->h; y++) {
+            for (size_t x = 0; x < window_surface->w; x++) {
+                p[y*window_surface->pitch/4+x] = lfb[y*400+x];
+            }
+        }
+        SDL_UnlockSurface(window_surface);
+        SDL_UpdateWindowSurface(window);
+        sleep(1);
+    }
+
+    return 0;
+}

tools/makefile

@@ -8,7 +8,7 @@ CFLAGS=$(WARNINGS) $(NOWARNINGS) -std=c11 -O2 \
 LDFLAGS=-no-pie
 
 all: mkdirrange mkfilepattern lfbviewx randdir covpreproc mkdoubledirs \
-     gensamehash mksamehash
+     gensamehash mksamehash lfbview
 
 gensamehash: gensamehash.c
 	$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
@@ -28,6 +28,8 @@ mkfilepattern: mkfilepattern.c
 lfbviewx: lfbviewx.c
 	$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@ -lX11 -lXext -D_GNU_SOURCE
 
+lfbview: lfbview.c
+	$(CC) `sdl2-config --cflags --libs` -o $@ $< -D_GNU_SOURCE
 randdir: randdir.c
 	$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
 
@@ -38,4 +40,4 @@ covpreproc: covpreproc.c
 
 clean:
 	rm -f *.o mkdirrange mkfilepattern lfbviewx randdir covpreproc \
-          mkdoubledirs gensamehash mksamehash
+          mkdoubledirs gensamehash mksamehash lfbview