Simplify sysmerge --booting as a real daemon.

init/init.8

@@ -121,7 +121,7 @@ corresponding partition devices in
 If the target is
 .Sy chain
 or
-.Sy chain-merge ,
+.Sy chain-sysmerge ,
 then the real operating system is chain initialized.
 .Pp
 The root filesystem is mounted per
@@ -149,7 +149,7 @@ program (or
 .Ar chain-init
 if specified) of the target root filesystem is run inside a chroot.
 If the target is
-.Sy chain-merge ,
+.Sy chain-sysmerge ,
 then the
 .Fl \-static-prefix=/sysmerge
 .Fl \-target=merge

init/init.c

@@ -3632,7 +3632,7 @@ int main(int argc, char* argv[])
 	// If the default daemon's top level dependency is a chain boot target, then
 	// chain boot the actual root filesystem.
 	if ( !strcmp(first_requirement, "chain") ||
-	     !strcmp(first_requirement, "chain-merge") )
+	     !strcmp(first_requirement, "chain-sysmerge") )
 	{
 		int next_argc = argc - optind;
 		char** next_argv = argv + optind;
@@ -3689,14 +3689,14 @@ int main(int argc, char* argv[])
 			const char* program = next_argv[0];
 			char verbose_opt[] = {'-', "sqv"[verbosity], '\0'};
 			// Chain boot the operating system upgrade if needed.
-			if ( !strcmp(first_requirement, "chain-merge") )
+			if ( !strcmp(first_requirement, "chain-sysmerge") )
 			{
 				program = "/sysmerge/sbin/init";
 				// TODO: Concat next_argv onto this argv_next, so the arguments
 				//       can be passed to the final init.
 				next_argv =
 					(char*[]) { (char*) program, "--static-prefix=/sysmerge",
-					            "--target=merge", verbose_opt, NULL };
+					            "--target=sysmerge", verbose_opt, NULL };
 			}
 			else if ( next_argc < 1 )
 			{
@@ -3731,7 +3731,7 @@ int main(int argc, char* argv[])
 
 	// TODO: After releasing Sortix 1.1, remove this compatibility since a
 	// sysmerge from 1.0 will not have a /var/log directory.
-	if ( !strcmp(first_requirement, "merge") &&
+	if ( !strcmp(first_requirement, "sysmerge") &&
 	     access(log_path, F_OK) < 0 )
 		mkdir(log_path, 0755);
 
@@ -3747,41 +3747,6 @@ int main(int argc, char* argv[])
 	set_kblayout();
 	set_videomode();
 
-	// Run the operating system upgrade if requested.
-	if ( !strcmp(first_requirement, "merge") )
-	{
-		pid_t child_pid = fork();
-		if ( child_pid < 0 )
-			fatal("fork: %m");
-		if ( !child_pid )
-		{
-			uninstall_signal_handler();
-			const char* argv[] = { "sysmerge", "--booting", NULL };
-			execvp(argv[0], (char* const*) argv);
-			fatal("Failed to load system upgrade: %s: %m", argv[0]);
-		}
-		forward_signal_pid = child_pid;
-		sigprocmask(SIG_UNBLOCK, &handled_signals, NULL);
-		int status;
-		while ( waitpid(child_pid, &status, 0) < 0 )
-		{
-			if ( errno != EINTR )
-				fatal("waitpid: %m");
-		}
-		sigprocmask(SIG_BLOCK, &handled_signals, NULL);
-		forward_signal_pid = -1; // Racy with waitpid.
-		if ( WIFEXITED(status) && WEXITSTATUS(status) != 0 )
-			fatal("Automatic upgrade failed: Exit status %i",
-			      WEXITSTATUS(status));
-		else if ( WIFSIGNALED(status) )
-			fatal("Automatic upgrade failed: %s", strsignal(WTERMSIG(status)));
-		else if ( !WIFEXITED(status) )
-			fatal("Automatic upgrade failed: Unexpected unusual termination");
-		// Soft reinit into the freshly upgraded operating system.
-		// TODO: Use next_argv here.
-		reinit();
-	}
-
 	// TODO: Use the arguments to specify additional things the default daemon
 	//       should depend on, as well as a denylist of things not to start
 	//       even if in default's dependencies. The easiest thing is probably to

share/init/sysmerge

@@ -0,0 +1,3 @@
+echo true
+exit-code-meaning poweroff-reboot
+exec sysmerge --booting

share/man/man5/init.5

@@ -149,6 +149,12 @@ inside the
 graphical user interface environment.
 This operating system mode is insecure because it boots straight to root access
 without a password.
+.It Sy sysmerge
+Perform an already scheduled operating system upgrade by invoking
+.Xr sysmerge 8
+.Fl \-booting
+and then reinit into the freshly upgraded system.
+It does not depend on any daemons to minimize the upgrade environment.
 .It Sy sysupgrade
 Starts the operating system upgrader.
 This foreground daemon starts the

sysinstall/sysmerge.8

@@ -135,7 +135,7 @@ has a new
 that runs
 .Sy /sysmerge/sbin/sysmerge --booting
 on boot through the
-.Sy chain-merge
+.Sy chain-sysmerge
 .Xr init 8
 boot target, which performs the operating system upgrade.
 The bootloader configuration is regenerated with a menu option to perform

sysinstall/sysmerge.c

@@ -580,5 +580,6 @@ int main(int argc, char* argv[])
 	else
 		printf("Successfully upgraded %s.\n", target);
 
-	return 0;
+	// Reinitialize the operating system if upgrading on boot.
+	return booting ? 3 : 0;
 }

update-initrd/update-initrd

@@ -85,7 +85,7 @@ cp "$sysroot/etc/fstab" "$tmp/etc/fstab"
 mkdir "$tmp/etc/init"
 if $sysmerge; then
   cat > "$tmp/etc/init/default" << EOF
-require chain-merge exit-code
+require chain-sysmerge exit-code
 EOF
 else
   cat > "$tmp/etc/init/default" << EOF