Merge "Revert "Revert "sdcard: Support sdcardfs""" into nyc-dev am: 71f6b95 (1b90ba84) · Commits · e / os / android_system_core

sdcard/sdcard.c

+104 −1

Original line number	Diff line number	Diff line
		@@ -1894,6 +1894,105 @@ static void run(const char* source_path, const char* label, uid_t uid,
		exit(1);
		}

		static int sdcardfs_setup(const char source_path, const char dest_path, uid_t fsuid,
		gid_t fsgid, bool multi_user, userid_t userid, gid_t gid, mode_t mask) {
		char opts[256];

		snprintf(opts, sizeof(opts),
		"fsuid=%d,fsgid=%d,%smask=%d,userid=%d,gid=%d",
		fsuid, fsgid, multi_user?"multiuser,":"", mask, userid, gid);

		if (mount(source_path, dest_path, "sdcardfs",
		MS_NOSUID \| MS_NODEV \| MS_NOEXEC \| MS_NOATIME, opts) != 0) {
		ERROR("failed to mount sdcardfs filesystem: %s\n", strerror(errno));
		return -1;
		}

		return 0;
		}

		static void run_sdcardfs(const char* source_path, const char* label, uid_t uid,
		gid_t gid, userid_t userid, bool multi_user, bool full_write) {
		char dest_path_default[PATH_MAX];
		char dest_path_read[PATH_MAX];
		char dest_path_write[PATH_MAX];
		char obb_path[PATH_MAX];
		snprintf(dest_path_default, PATH_MAX, "/mnt/runtime/default/%s", label);
		snprintf(dest_path_read, PATH_MAX, "/mnt/runtime/read/%s", label);
		snprintf(dest_path_write, PATH_MAX, "/mnt/runtime/write/%s", label);

		umask(0);
		if (multi_user) {
		/* Multi-user storage is fully isolated per user, so "other"
		* permissions are completely masked off. */
		if (sdcardfs_setup(source_path, dest_path_default, uid, gid, multi_user, userid,
		AID_SDCARD_RW, 0006)
		\|\| sdcardfs_setup(source_path, dest_path_read, uid, gid, multi_user, userid,
		AID_EVERYBODY, 0027)
		\|\| sdcardfs_setup(source_path, dest_path_write, uid, gid, multi_user, userid,
		AID_EVERYBODY, full_write ? 0007 : 0027)) {
		ERROR("failed to fuse_setup\n");
		exit(1);
		}
		} else {
		/* Physical storage is readable by all users on device, but
		* the Android directories are masked off to a single user
		* deep inside attr_from_stat(). */
		if (sdcardfs_setup(source_path, dest_path_default, uid, gid, multi_user, userid,
		AID_SDCARD_RW, 0006)
		\|\| sdcardfs_setup(source_path, dest_path_read, uid, gid, multi_user, userid,
		AID_EVERYBODY, full_write ? 0027 : 0022)
		\|\| sdcardfs_setup(source_path, dest_path_write, uid, gid, multi_user, userid,
		AID_EVERYBODY, full_write ? 0007 : 0022)) {
		ERROR("failed to fuse_setup\n");
		exit(1);
		}
		}

		/* Drop privs */
		if (setgroups(sizeof(kGroups) / sizeof(kGroups[0]), kGroups) < 0) {
		ERROR("cannot setgroups: %s\n", strerror(errno));
		exit(1);
		}
		if (setgid(gid) < 0) {
		ERROR("cannot setgid: %s\n", strerror(errno));
		exit(1);
		}
		if (setuid(uid) < 0) {
		ERROR("cannot setuid: %s\n", strerror(errno));
		exit(1);
		}

		if (multi_user) {
		snprintf(obb_path, sizeof(obb_path), "%s/obb", source_path);
		fs_prepare_dir(&obb_path[0], 0775, uid, gid);
		}

		exit(0);
		}

		static bool supports_sdcardfs(void) {
		FILE *fp;
		char *buf = NULL;
		size_t buflen = 0;

		fp = fopen("/proc/filesystems", "r");
		if (!fp) {
		ERROR("Could not read /proc/filesystems, error: %s\n", strerror(errno));
		return false;
		}
		while ((getline(&buf, &buflen, fp)) > 0) {
		if (strstr(buf, "sdcardfs\n")) {
		free(buf);
		fclose(fp);
		return true;
		}
		}
		free(buf);
		fclose(fp);
		return false;
		}

		int main(int argc, char **argv) {
		const char *source_path = NULL;
		const char *label = NULL;
		@@ -1966,6 +2065,10 @@ int main(int argc, char **argv) {
		sleep(1);
		}

		if (supports_sdcardfs()) {
		run_sdcardfs(source_path, label, uid, gid, userid, multi_user, full_write);
		} else {
		run(source_path, label, uid, gid, userid, multi_user, full_write);
		}
		return 1;
		}