Make user's home specific to the prefix, provide a link to real home via LinuxHome

CMakeLists.txt

@@ -97,8 +97,6 @@ install(DIRECTORY DESTINATION libexec/darling/usr/local/share)
 
 InstallSymlink(/Volumes/SystemRoot/dev ${CMAKE_INSTALL_PREFIX}/libexec/darling/dev)
 InstallSymlink(private/tmp ${CMAKE_INSTALL_PREFIX}/libexec/darling/tmp)
-InstallSymlink(/Volumes/SystemRoot/home ${CMAKE_INSTALL_PREFIX}/libexec/darling/Users)
-InstallSymlink(Users ${CMAKE_INSTALL_PREFIX}/libexec/darling/home)
 
 InstallSymlink(/proc/self/mounts ${CMAKE_INSTALL_PREFIX}/libexec/darling/etc/mtab)
 InstallSymlink(/Volumes/SystemRoot/etc/passwd ${CMAKE_INSTALL_PREFIX}/libexec/darling/etc/passwd)

src/libelfloader/loader.c

@@ -84,16 +84,36 @@ __attribute__((constructor))
 
 static unsigned long processEnvVariable(const char* var)
 {
-	if (strncmp(var, "HOME=/Users/", 12) == 0)
+	if (strncmp(var, "HOME=", 5) == 0)
 	{
-		const size_t len = strlen(var);
-		char* home = malloc(len); // 1 byte shorter
+		char* home = (char*) malloc(512);
+		char* symlink_path = (char*) malloc(strlen(var+5) + 10);
 
-		strcpy(home, "HOME=/home/");
-		strcpy(home + 11, var+12);
+		strcpy(symlink_path, var+5);
+		strcat(symlink_path, "/LinuxHome");
+
+		int len = readlink(symlink_path, home, 512-1);
+		free(symlink_path);
+
+		if (len < 0)
+		{
+			free(home);
+			goto out;
+		}
+		home[len] = '\0';
+
+		if (strncmp(home, SYSTEM_ROOT, sizeof(SYSTEM_ROOT) - 1) != 0)
+		{
+			free(home);
+			goto out;
+		}
+
+		strcpy(home, "HOME=");
+		memmove(home+5, home + sizeof(SYSTEM_ROOT) - 1, len - sizeof(SYSTEM_ROOT) + 2);
 
 		return (unsigned long) home;
 	}
+out:
 	return (unsigned long) var;
 }
 

src/startup/darling.c

@@ -1,7 +1,7 @@
 /*
 This file is part of Darling.
 
-Copyright (C) 2016-2018 Lubos Dolezel
+Copyright (C) 2016-2020 Lubos Dolezel
 
 Darling is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -561,16 +561,16 @@ void spawnShell(const char** argv)
 		"/sbin:"
 		"/usr/local/bin");
 
-	const char *home = getenv("HOME");
-	if (home)
+	const char* login = getlogin();
+	if (!login)
 	{
-		if (sscanf(home, "/home/%4096s", buffer1) == 1)
-			snprintf(buffer2, sizeof(buffer2), "HOME=/Users/%s", buffer1);
-		else
-			snprintf(buffer2, sizeof(buffer2), "HOME=" SYSTEM_ROOT "%s", home);
-		pushShellspawnCommand(sockfd, SHELLSPAWN_SETENV, buffer2);
+		fprintf(stderr, "Cannot determine your user name\n");
+		exit(1);
 	}
 
+	snprintf(buffer2, sizeof(buffer2), "HOME=/Users/%s", login);
+	pushShellspawnCommand(sockfd, SHELLSPAWN_SETENV, buffer2);
+
 	// Push shell arguments
 	if (buffer != NULL)
 	{
@@ -747,6 +747,8 @@ pid_t spawnInitProcess(void)
 
 		free(opts);
 
+		setupUserHome();
+
 		// This is executed once at prefix creation
 		if (g_fixPermissions)
 		fixDirectoryPermissions(prefix);
@@ -1238,3 +1240,96 @@ void setupCoredumpPattern(void)
 		fclose(f);
 	}
 }
+
+const char* xdgDirectory(const char* name)
+{
+	static char dir[4096];
+	char* cmd = (char*) malloc(16 + strlen(name));
+
+	sprintf(cmd, "xdg-user-dir %s", name);
+
+	FILE* proc = popen(cmd, "r");
+
+	free(cmd);
+
+	if (!proc)
+		return NULL;
+
+	fgets(dir, sizeof(dir)-1, proc);
+
+	pclose(proc);
+
+	size_t len = strlen(dir);
+	if (len <= 1)
+		return NULL;
+
+	if (dir[len-1] == '\n')
+		dir[len-1] = '\0';
+	return dir;
+}
+
+void setupUserHome(void)
+{
+	char buf[4096], buf2[4096];
+
+	snprintf(buf, sizeof(buf), "%s/Users", prefix);
+
+	// Remove the old /Users symlink that may exist
+	unlink(buf);
+
+	// mkdir /Users
+	mkdir(buf, 0777);
+
+	// mkdir /Users/Shared
+	strcat(buf, "/Shared");
+	mkdir(buf, 0777);
+
+	const char* home = getenv("HOME");
+	const char* login = getlogin();
+	if (!login)
+	{
+		fprintf(stderr, "Cannot determine your user name\n");
+		exit(1);
+	}
+	if (!home)
+	{
+		fprintf(stderr, "Cannot determine your home directory\n");
+		exit(1);
+	}
+
+	snprintf(buf, sizeof(buf), "%s/Users/%s", prefix, login);
+
+	// mkdir /Users/$LOGIN
+	mkdir(buf, 0755);
+
+	snprintf(buf2, sizeof(buf2), "/Volumes/SystemRoot%s", home);
+
+	strcat(buf, "/LinuxHome");
+	unlink(buf);
+
+	// symlink /Users/$LOGIN/LinuxHome -> $HOME
+	symlink(buf2, buf);
+
+	static const char* xdgmap[][2] = {
+		{ "DESKTOP", "Desktop" },
+		{ "DOWNLOAD", "Downloads" },
+		{ "PUBLICSHARE", "Public" },
+		{ "DOCUMENTS", "Documents" },
+		{ "MUSIC", "Music" },
+		{ "PICTURES", "Pictures" },
+		{ "VIDEOS", "Movies" },
+	};
+
+	for (int i = 0; i < sizeof(xdgmap) / sizeof(xdgmap[0]); i++)
+	{
+		const char* dir = xdgDirectory(xdgmap[i][0]);
+		if (!dir)
+			continue;
+		
+		snprintf(buf2, sizeof(buf2), "/Volumes/SystemRoot%s", dir);
+		snprintf(buf, sizeof(buf), "%s/Users/%s/%s", prefix, login, xdgmap[i][1]);
+
+		unlink(buf);
+		symlink(buf2, buf);
+	}
+}

src/startup/darling.h

@@ -67,5 +67,6 @@ void loadKernelModule(void);
 void joinNamespace(pid_t pid, int type, const char* typeName);
 
 void setupCoredumpPattern(void);
+void setupUserHome(void);
 
 #endif