Add busybox patch to see debug lines: initrd sh ok

The switch_root command seems to hang in the execv() syscall.

busybox-debug.patch

@@ -0,0 +1,68 @@
+Only in busybox-1.36.1-mod: tags
+diff -up -r busybox-1.36.1/util-linux/switch_root.c busybox-1.36.1-mod/util-linux/switch_root.c
+--- busybox-1.36.1/util-linux/switch_root.c	2021-09-30 00:04:47.000000000 +0200
++++ busybox-1.36.1-mod/util-linux/switch_root.c	2024-07-01 16:08:28.336541504 +0200
+@@ -181,6 +181,8 @@ int switch_root_main(int argc UNUSED_PAR
+ 	unsigned dry_run = 0;
+ 	dev_t rootdev;
+ 
++	printf("HELLO THIS IS SWITCH ROOT STARTING\n");
++
+ 	// Parse args. '+': stop at first non-option
+ 	if (ENABLE_SWITCH_ROOT && (!ENABLE_RUN_INIT || applet_name[0] == 's')) {
+ //usage:#define switch_root_trivial_usage
+@@ -241,12 +243,15 @@ int switch_root_main(int argc UNUSED_PAR
+ 	if (stat("/init", &st) != 0 || !S_ISREG(st.st_mode)) {
+ 		bb_error_msg_and_die("'%s' is not a regular file", "/init");
+ 	}
++	printf("SWITCH ROOT LINE %d OK\n", __LINE__);
+ 	statfs("/", &stfs); // this never fails
++	printf("SWITCH ROOT LINE %d OK\n", __LINE__);
+ 	if ((unsigned)stfs.f_type != RAMFS_MAGIC
+ 	 && (unsigned)stfs.f_type != TMPFS_MAGIC
+ 	) {
+ 		bb_simple_error_msg_and_die("root filesystem is not ramfs/tmpfs");
+ 	}
++	printf("SWITCH ROOT LINE %d OK\n", __LINE__);
+ 
+ 	if (!dry_run) {
+ 		// Zap everything out of rootdev
+@@ -258,19 +263,26 @@ int switch_root_main(int argc UNUSED_PAR
+ 			bb_simple_perror_msg_and_die("error moving root");
+ 		}
+ 	}
++	printf("SWITCH ROOT LINE %d OK\n", __LINE__);
++	printf("XCHROOT\n");
+ 	xchroot(".");
++	printf("SWITCH ROOT LINE %d OK\n", __LINE__);
+ 	// The chdir is needed to recalculate "." and ".." links
+ 	/*xchdir("/"); - done in xchroot */
+ 
+ 	// If a new console specified, redirect stdin/stdout/stderr to it
+ 	if (console) {
++		printf("REDIRECTING CONSOLE\n");
++		printf("SWITCH ROOT LINE %d OK\n", __LINE__);
+ 		int fd = open_or_warn(console, O_RDWR);
+ 		if (fd >= 0) {
+ 			xmove_fd(fd, 0);
+ 			xdup2(0, 1);
+ 			xdup2(0, 2);
+ 		}
++		printf("SWITCH ROOT LINE %d OK\n", __LINE__);
+ 	}
++	printf("SWITCH ROOT LINE %d OK\n", __LINE__);
+ 
+ 	if (dry_run) {
+ 		// Does NEW_INIT look like it can be executed?
+@@ -280,8 +292,11 @@ int switch_root_main(int argc UNUSED_PAR
+ 		if (access(argv[0], X_OK) == 0)
+ 			return 0;
+ 	} else {
++		printf("SWITCH ROOT LINE %d OK\n", __LINE__);
++		printf("LAUNCHING EXECV\n");
+ 		// Exec NEW_INIT
+ 		execv(argv[0], argv);
++		printf("RETURNED FROM EXECV???\n");
+ 	}
+ 	bb_perror_msg_and_die("can't execute '%s'", argv[0]);
+ }

lagarto-ox.nix

@@ -107,14 +107,10 @@
   };
 
   nixpkgs.overlays = [ (final: prev: {
-    # FIXME: Fails on start
+    #busybox = prev.busybox.overrideAttrs (old: {
-    busybox = (prev.busybox.override {
+    #  # Print some debug lines on switch_root to see where it hangs.
-#      enableStatic = true;
+    #  patches = (old.patches or []) ++ [ ./busybox-debug.patch ];
-    }).overrideAttrs (old: {
+    #});
-      src = /home/Computational/rarias/riscv/busybox-1.36.1;
-#      #env.NIX_CFLAGS_COMPILE = "-mtune=generic";
-#      #env.NIX_DEBUG = 5;
-    });
 
     linuxPackages_latest = prev.linuxPackages_latest;
     #linuxPackages_latest = prev.linuxPackages_latest.extend (lib.const (ksuper: {