Merge lp:~jdstrand/snap-confine/coding-style into lp:~snappy-dev/snap-confine/trunk

[Jamie Strandboge]

  * enforce coding style:
    - add syntax-check and fmt Makefile targets
    - use 'indent -linux'
    - debian/control: Build-Depends on indent

[Michael Vogt (mvo)]

Looks great, thanks for this. Unfortunate that we loose the bzr blame info but thats life.

review: Approve

[Jamie Strandboge (jdstrand)]

hrmm, yes, oh well. Thanks!

=== modified file 'Makefile'
--- Makefile	2016-02-25 15:02:17 +0000
+++ Makefile	2016-03-22 12:19:24 +0000
@@ -8,5 +8,8 @@
 	make -C src $@
 	make -C tests $@
 
-check: all
+syntax-check:
+	make -C src syntax-check
+
+check: all syntax-check
 	make -C tests test
 
=== modified file 'debian/changelog'
--- debian/changelog	2016-03-22 11:23:59 +0000
+++ debian/changelog	2016-03-22 12:19:24 +0000
@@ -1,6 +1,10 @@
 ubuntu-core-launcher (1.0.21) UNRELEASED; urgency=medium
   * src/main.c: setup private /dev/pts
   * debian/usr.bin.ubuntu-core-launcher: allow mounting /dev/pts
+  * enforce coding style:
+    - add syntax-check and fmt Makefile targets
+    - use 'indent -linux'
+    - debian/control: Build-Depends on indent
 
  -- Jamie Strandboge <[e-mail]>  Tue, 22 Mar 2016 06:23:38 -0500
 
 
=== modified file 'debian/control'
--- debian/control	2016-01-26 15:11:20 +0000
+++ debian/control	2016-03-22 12:19:24 +0000
@@ -2,7 +2,7 @@
 Section: utils
 Priority: optional
 Maintainer: Ubuntu Developers <[e-mail]>
-Build-Depends: debhelper (>= 9), libseccomp-dev, libapparmor-dev, libudev-dev, dh-apparmor
+Build-Depends: debhelper (>= 9), libseccomp-dev, libapparmor-dev, libudev-dev, dh-apparmor, indent
 Standards-Version: 3.9.6
 Vcs-Bzr: lp:~snappy-dev/ubuntu-core-launcher/trunk
 
 
=== modified file 'src/Makefile'
--- src/Makefile	2015-05-06 11:26:07 +0000
+++ src/Makefile	2016-03-22 12:19:24 +0000
@@ -2,8 +2,11 @@
 CFLAGS= -D_GNU_SOURCE -O2 -Wall -Werror $(shell dpkg-buildflags --get CFLAGS)
 LD_FLAGS = $(shell dpkg-buildflags --get LDFLAGS)
 LIBS = -lapparmor -lseccomp -ludev
+TMPDIR = ./tmp
+FMT = indent -linux
 
 BIN = ubuntu-core-launcher
+HDRS = $(wildcard *.h)
 SRCS = $(wildcard *.c)
 OBJS = $(SRCS:.c=.o)
 
@@ -15,7 +18,23 @@
 
 distclean: clean
 clean:
-	rm -f *.o ${BIN}
+	rm -f *.o $(BIN) *~
+	rm -rf $(TMPDIR)
+
+fmt:
+	for f in $(HDRS) $(SRCS); do \
+		echo "$(FMT) $$f ... "; \
+		$(FMT) "$$f"; \
+	done; \
+
+syntax-check:
+	$(shell mkdir $(TMPDIR) 2>/dev/null)
+	for f in $(HDRS) $(SRCS); do \
+		out=$(TMPDIR)/$$f.out; \
+		echo "Checking '$(FMT) $$f' ... "; \
+		$(FMT) "$$f" -o "$$out"; \
+		diff -Naur "$$f" "$$out" || exit 1; \
+	done; \
 
 install:
 	# create dirs
 
=== modified file 'src/main.c'
--- src/main.c	2016-03-21 17:33:08 +0000
+++ src/main.c	2016-03-22 12:19:24 +0000
@@ -41,498 +41,500 @@
 
 #define MAX_BUF 1000
 
-bool verify_appname(const char *appname) {
-   // these chars are allowed in a appname
-   const char* whitelist_re = "^[a-z0-9][a-z0-9+._-]+$";
-   regex_t re;
-   if (regcomp(&re, whitelist_re, REG_EXTENDED|REG_NOSUB) != 0)
-      die("can not compile regex %s", whitelist_re);
-
-   int status = regexec(&re, appname, 0, NULL, 0);
-   regfree(&re);
-
-   return (status == 0);
-}
-
-void run_snappy_app_dev_add(struct udev *u, const char *path, const char *appname) {
-   debug("run_snappy_app_dev_add: %s %s", path, appname);
-      struct udev_device *d = udev_device_new_from_syspath(u, path);
-      if (d == NULL)
-         die("can not find %s", path);
-      dev_t devnum = udev_device_get_devnum (d);
-      udev_device_unref(d);
-
-      int status = 0;
-      pid_t pid = fork();
-      if (pid == 0) {
-         char buf[64];
-         unsigned major = MAJOR(devnum);
-         unsigned minor = MINOR(devnum);
-         must_snprintf(buf, sizeof(buf), "%u:%u", major, minor);
-         if(execl("/lib/udev/snappy-app-dev", "/lib/udev/snappy-app-dev", "add", appname, path, buf, NULL) != 0)
-            die("execlp failed");
-      }
-      if(waitpid(pid, &status, 0) < 0)
-         die("waitpid failed");
-      if(WIFEXITED(status) && WEXITSTATUS(status) != 0)
-         die("child exited with status %i", WEXITSTATUS(status));
-      else if(WIFSIGNALED(status))
-         die("child died with signal %i", WTERMSIG(status));
-}
-
-void setup_udev_snappy_assign(const char *appname) {
-   debug("setup_udev_snappy_assign");
-
-   struct udev *u = udev_new();
-   if (u == NULL)
-      die("udev_new failed");
-
-   const char* static_devices[] = {
-      "/sys/class/mem/null",
-      "/sys/class/mem/full",
-      "/sys/class/mem/zero",
-      "/sys/class/mem/random",
-      "/sys/class/mem/urandom",
-      "/sys/class/tty/tty",
-      "/sys/class/tty/console",
-      "/sys/class/tty/ptmx",
-      NULL,
-   };
-   int i;
-   for(i=0; static_devices[i] != NULL; i++) {
-      run_snappy_app_dev_add(u, static_devices[i], appname);
-   }
-
-   struct udev_enumerate *devices = udev_enumerate_new(u);
-   if (devices == NULL)
-      die("udev_enumerate_new failed");
-
-   if (udev_enumerate_add_match_tag (devices, "snappy-assign") != 0)
-      die("udev_enumerate_add_match_tag");
-
-   if(udev_enumerate_add_match_property (devices, "SNAPPY_APP", appname) != 0)
-      die("udev_enumerate_add_match_property");
-
-   if(udev_enumerate_scan_devices(devices) != 0)
-      die("udev_enumerate_scan failed");
-
-   struct udev_list_entry *l = udev_enumerate_get_list_entry (devices);
-   while (l != NULL) {
-      const char *path = udev_list_entry_get_name (l);
-      if (path == NULL)
-         die("udev_list_entry_get_name failed");
-      run_snappy_app_dev_add(u, path, appname);
-      l = udev_list_entry_get_next(l);
-   }
-
-   udev_enumerate_unref(devices);
-   udev_unref(u);
-}
-
-void setup_devices_cgroup(const char *appname) {
-   debug("setup_devices_cgroup");
-
-   // extra paranoia
-   if(!verify_appname(appname))
-      die("appname %s not allowed", appname);
-
-   // create devices cgroup controller
-   char cgroup_dir[PATH_MAX];
-   must_snprintf(cgroup_dir, sizeof(cgroup_dir), "/sys/fs/cgroup/devices/snappy.%s/", appname);
-
-   if (mkdir(cgroup_dir, 0755) < 0 && errno != EEXIST)
-         die("mkdir failed");
-
-   // move ourselves into it
-   char cgroup_file[PATH_MAX];
-   must_snprintf(cgroup_file, sizeof(cgroup_file), "%s%s", cgroup_dir, "tasks");
-
-   char buf[128];
-   must_snprintf(buf, sizeof(buf), "%i", getpid());
-   write_string_to_file(cgroup_file, buf);
-
-   // deny by default
-   must_snprintf(cgroup_file, sizeof(cgroup_file), "%s%s", cgroup_dir, "devices.deny");
-   write_string_to_file(cgroup_file, "a");
-
-}
-
-bool snappy_udev_setup_required(const char *appname) {
-   debug("snappy_udev_setup_required");
-
-   // extra paranoia
-   if(!verify_appname(appname))
-      die("appname %s not allowed", appname);
-
-   char override_file[PATH_MAX];
-   must_snprintf(override_file, sizeof(override_file), "/var/lib/apparmor/clicks/%s.json.additional", appname);
-
-   // if a snap package gets unrestricted apparmor access we need to setup
-   // a device cgroup.
-   //
-   // the "needle" string is what gives this access so we search for that
-   // here
-   const char *needle =
-      "{"                          "\n"
-      " \"write_path\": ["         "\n"
-      "   \"/dev/**\""             "\n"
-      " ],"                        "\n"
-      " \"read_path\": ["          "\n"
-      "   \"/run/udev/data/*\""     "\n"
-      " ]\n"
-      "}";
-   debug("looking for: '%s'", needle);
-   char content[strlen(needle)];
-
-   int fd = open(override_file, O_CLOEXEC | O_NOFOLLOW | O_RDONLY);
-   if (fd < 0)
-      return false;
-   int n = read(fd, content, sizeof(content));
-   close(fd);
-   if (n < sizeof(content))
-      return false;
-
-   // memcpy so that we don't have to deal with \0 in the input
-   if (memcmp(content, needle, strlen(needle)) == 0) {
-      debug("found needle, need to apply udev setup");
-      return true;
-   }
-
-   return false;
-}
-
-bool is_running_on_classic_ubuntu() {
-   return (access("/var/lib/dpkg/status", F_OK) == 0);
-}
-
-void setup_private_mount(const char* appname) {
-    uid_t uid = getuid();
-    gid_t gid = getgid();
-    char tmpdir[MAX_BUF] = {0};
-
-    // Create a 0700 base directory, this is the base dir that is
-    // protected from other users.
-    //
-    // Under that basedir, we put a 1777 /tmp dir that is then bind
-    // mounted for the applications to use
-    must_snprintf(tmpdir, sizeof(tmpdir), "/tmp/snap.%d_%s_XXXXXX", uid, appname);
-    if (mkdtemp(tmpdir) == NULL) {
-        die("unable to create tmpdir");
-    }
-
-    // now we create a 1777 /tmp inside our private dir
-    mode_t old_mask = umask(0);
-    char *d = strdup(tmpdir);
-    if (!d) {
-        die("Out of memory");
-    }
-    must_snprintf(tmpdir, sizeof(tmpdir), "%s/tmp", d);
-    free(d);
-
-    if (mkdir(tmpdir, 01777) != 0) {
-       die("unable to create /tmp inside private dir");
-    }
-    umask(old_mask);
-
-    // MS_BIND is there from linux 2.4
-    if (mount(tmpdir, "/tmp", NULL, MS_BIND, NULL) != 0) {
-        die("unable to bind private /tmp");
-    }
-    // MS_PRIVATE needs linux > 2.6.11
-    if (mount("none", "/tmp", NULL, MS_PRIVATE, NULL) != 0) {
-       die("unable to make /tmp/ private");
-    }
-
-    // do the chown after the bind mount to avoid potential shenanigans
-    if (chown("/tmp/", uid, gid) < 0) {
-        die("unable to chown tmpdir");
-    }
-
-    // ensure we set the various TMPDIRs to our newly created tmpdir
-    const char *tmpd[] = {"TMPDIR", "TEMPDIR", "SNAP_APP_TMPDIR", NULL};
-    int i;
-    for (i=0; tmpd[i] != NULL; i++) {
-       if (setenv(tmpd[i], "/tmp", 1) != 0) {
-          die("unable to set '%s'", tmpd[i]);
-       }
-    }
-}
-
-void setup_private_pts() {
-    // See https://www.kernel.org/doc/Documentation/filesystems/devpts.txt
-    //
-    // Ubuntu by default uses devpts 'single-instance' mode where /dev/pts/ptmx
-    // is mounted with ptmxmode=0000. We don't want to change the startup
-    // scripts though, so we follow the instructions in point '4' of
-    // 'User-space changes' in the above doc. In other words, after
-    // unshare(CLONE_NEWNS), we mount devpts with -o newinstance,ptmxmode=0666
-    // and then bind mount /dev/pts/ptmx onto /dev/ptmx
-
-    struct stat st;
-
-    // Make sure /dev/pts/ptmx exists, otherwise we are in legacy mode which
-    // doesn't provide the isolation we require.
-    if (stat("/dev/pts/ptmx", &st) != 0) {
-        die("/dev/pts/ptmx does not exist");
-    }
-    // Make sure /dev/ptmx exists so we can bind mount over it
-    if (stat("/dev/ptmx", &st) != 0) {
-        die("/dev/ptmx does not exist");
-    }
-
-    // Since multi-instance, use ptmxmode=0666. The other options are copied
-    // from /etc/default/devpts
-    if (mount("devpts", "/dev/pts", "devpts", MS_MGC_VAL,
-              "newinstance,ptmxmode=0666,mode=0620,gid=5")) {
-        die("unable to mount a new instance of '/dev/pts'");
-    }
-
-    if (mount("/dev/pts/ptmx", "/dev/ptmx", "none", MS_BIND, 0)) {
-        die("unable to mount '/dev/pts/ptmx'->'/dev/ptmx'");
-    }
-}
-
-void setup_snappy_os_mounts() {
-   debug("setup_snappy_os_mounts()\n");
-
-   // FIXME: hardcoded "ubuntu-core.*"
-   glob_t glob_res;
-   if (glob("/snaps/ubuntu-core*/current/", 0, NULL, &glob_res) != 0) {
-      die("can not find a snappy os");
-   }
-   if ((glob_res.gl_pathc =! 1)) {
-      die("expected 1 os snap, found %i", (int)glob_res.gl_pathc);
-   }
-   char *mountpoint = glob_res.gl_pathv[0];
-
-   // we mount some whitelisted directories
-   //
-   // Note that we do not mount "/etc/" from snappy. We could do that,
-   // but if we do we need to ensure that data like /etc/{hostname,hosts,
-   // passwd,groups} is in sync between the two systems (probably via
-   // selected bind mounts of those files).
-   const char *mounts[] = {"/bin", "/sbin", "/lib", "/lib64", "/usr"};
-   for (int i=0; i < sizeof(mounts)/sizeof(char*); i++) {
-      // we mount the OS snap /bin over the real /bin in this NS
-      const char *dst = mounts[i];
-
-      char buf[512];
-      must_snprintf(buf, sizeof(buf), "%s%s", mountpoint, dst);
-      const char *src = buf;
-
-      debug("mounting %s -> %s\n", src, dst);
-      if (mount(src, dst, NULL, MS_BIND, NULL) != 0) {
-         die("unable to bind %s to %s", src, dst);
-      }
-   }
-
-   globfree(&glob_res);
-}
-
-void setup_slave_mount_namespace() {
-   // unshare() and CLONE_NEWNS require linux >= 2.6.16 and glibc >= 2.14
-   // if using an older glibc, you'd need -D_BSD_SOURCE or -D_SVID_SORUCE.
-   if (unshare(CLONE_NEWNS) < 0) {
-      die("unable to set up mount namespace");
-   }
-
-   // make our "/" a rslave of the real "/". this means that
-   // mounts from the host "/" get propagated to our namespace
-   // (i.e. we see new media mounts)
-   if (mount("none", "/", NULL, MS_REC|MS_SLAVE, NULL) != 0) {
-      die("can not make make / rslave");
-   }
-}
-
-void mkpath(const char *const path) {
-   // If asked to create an empty path, return immediately.
-   if (strlen(path) == 0) {
-      return;
-   }
-
-   // We're going to use strtok_r, which needs to modify the path, so we'll make
-   // a copy of it.
-   char *path_copy = strdup(path);
-   if (path_copy == NULL) {
-      die("failed to create user data directory");
-   }
-
-   // Open flags to use while we walk the user data path:
-   // - Don't follow symlinks
-   // - Don't allow child access to file descriptor
-   // - Only open a directory (fail otherwise)
-   int open_flags = O_NOFOLLOW | O_CLOEXEC | O_DIRECTORY;
-
-   // We're going to create each path segment via openat/mkdirat calls instead
-   // of mkdir calls, to avoid following symlinks and placing the user data
-   // directory somewhere we never intended for it to go. The first step is to
-   // get an initial file descriptor.
-   int fd = AT_FDCWD;
-   if (path_copy[0] == '/') {
-      fd = open("/", open_flags);
-      if (fd < 0) {
-         free(path_copy);
-         die("failed to create user data directory");
-      }
-   }
-
-   // strtok_r needs a pointer to keep track of where it is in the string.
-   char *path_walker;
-
-   // Initialize tokenizer and obtain first path segment.
-   char *path_segment = strtok_r(path_copy, "/", &path_walker);
-   while (path_segment) {
-      // Try to create the directory. It's okay if it already existed, but any
-      // other error is fatal.
-      if (mkdirat(fd, path_segment, 0755) < 0 && errno != EEXIST) {
-         close(fd);
-         free(path_copy);
-         die("failed to create user data directory");
-      }
-
-      // Open the parent directory we just made (and close the previous one) so
-      // we can continue down the path.
-      int previous_fd = fd;
-      fd = openat(fd, path_segment, open_flags);
-      close(previous_fd);
-      if (fd < 0) {
-         free(path_copy);
-         die("failed to create user data directory");
-      }
-
-      // Obtain the next path segment.
-      path_segment = strtok_r(NULL, "/", &path_walker);
-   }
-
-   // Close the descriptor for the final directory in the path.
-   close(fd);
-
-   free(path_copy);
-}
-
-void setup_user_data() {
-   const char *user_data = getenv("SNAP_USER_DATA");
-
-   // If $SNAP_USER_DATA wasn't defined, check the deprecated
-   // $SNAP_APP_USER_DATA_PATH.
-   if (user_data == NULL) {
-      user_data = getenv("SNAP_APP_USER_DATA_PATH");
-      // If it's still not defined, there's nothing to do. No need to die,
-      // there's simply no directory to create.
-      if (user_data == NULL) {
-         return;
-      }
-   }
-
-   // Only support absolute paths.
-   if (user_data[0] != '/') {
-      die("user data directory must be an absolute path");
-   }
-
-   mkpath(user_data);
+bool verify_appname(const char *appname)
+{
+	// these chars are allowed in a appname
+	const char *whitelist_re = "^[a-z0-9][a-z0-9+._-]+$";
+	regex_t re;
+	if (regcomp(&re, whitelist_re, REG_EXTENDED | REG_NOSUB) != 0)
+		die("can not compile regex %s", whitelist_re);
+
+	int status = regexec(&re, appname, 0, NULL, 0);
+	regfree(&re);
+
+	return (status == 0);
+}
+
+void run_snappy_app_dev_add(struct udev *u, const char *path,
+			    const char *appname)
+{
+	debug("run_snappy_app_dev_add: %s %s", path, appname);
+	struct udev_device *d = udev_device_new_from_syspath(u, path);
+	if (d == NULL)
+		die("can not find %s", path);
+	dev_t devnum = udev_device_get_devnum(d);
+	udev_device_unref(d);
+
+	int status = 0;
+	pid_t pid = fork();
+	if (pid == 0) {
+		char buf[64];
+		unsigned major = MAJOR(devnum);
+		unsigned minor = MINOR(devnum);
+		must_snprintf(buf, sizeof(buf), "%u:%u", major, minor);
+		if (execl
+		    ("/lib/udev/snappy-app-dev", "/lib/udev/snappy-app-dev",
+		     "add", appname, path, buf, NULL) != 0)
+			die("execlp failed");
+	}
+	if (waitpid(pid, &status, 0) < 0)
+		die("waitpid failed");
+	if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
+		die("child exited with status %i", WEXITSTATUS(status));
+	else if (WIFSIGNALED(status))
+		die("child died with signal %i", WTERMSIG(status));
+}
+
+void setup_udev_snappy_assign(const char *appname)
+{
+	debug("setup_udev_snappy_assign");
+
+	struct udev *u = udev_new();
+	if (u == NULL)
+		die("udev_new failed");
+
+	const char *static_devices[] = {
+		"/sys/class/mem/null",
+		"/sys/class/mem/full",
+		"/sys/class/mem/zero",
+		"/sys/class/mem/random",
+		"/sys/class/mem/urandom",
+		"/sys/class/tty/tty",
+		"/sys/class/tty/console",
+		"/sys/class/tty/ptmx",
+		NULL,
+	};
+	int i;
+	for (i = 0; static_devices[i] != NULL; i++) {
+		run_snappy_app_dev_add(u, static_devices[i], appname);
+	}
+
+	struct udev_enumerate *devices = udev_enumerate_new(u);
+	if (devices == NULL)
+		die("udev_enumerate_new failed");
+
+	if (udev_enumerate_add_match_tag(devices, "snappy-assign") != 0)
+		die("udev_enumerate_add_match_tag");
+
+	if (udev_enumerate_add_match_property(devices, "SNAPPY_APP", appname) !=
+	    0)
+		die("udev_enumerate_add_match_property");
+
+	if (udev_enumerate_scan_devices(devices) != 0)
+		die("udev_enumerate_scan failed");
+
+	struct udev_list_entry *l = udev_enumerate_get_list_entry(devices);
+	while (l != NULL) {
+		const char *path = udev_list_entry_get_name(l);
+		if (path == NULL)
+			die("udev_list_entry_get_name failed");
+		run_snappy_app_dev_add(u, path, appname);
+		l = udev_list_entry_get_next(l);
+	}
+
+	udev_enumerate_unref(devices);
+	udev_unref(u);
+}
+
+void setup_devices_cgroup(const char *appname)
+{
+	debug("setup_devices_cgroup");
+
+	// extra paranoia
+	if (!verify_appname(appname))
+		die("appname %s not allowed", appname);
+
+	// create devices cgroup controller
+	char cgroup_dir[PATH_MAX];
+	must_snprintf(cgroup_dir, sizeof(cgroup_dir),
+		      "/sys/fs/cgroup/devices/snappy.%s/", appname);
+
+	if (mkdir(cgroup_dir, 0755) < 0 && errno != EEXIST)
+		die("mkdir failed");
+
+	// move ourselves into it
+	char cgroup_file[PATH_MAX];
+	must_snprintf(cgroup_file, sizeof(cgroup_file), "%s%s", cgroup_dir,
+		      "tasks");
+
+	char buf[128];
+	must_snprintf(buf, sizeof(buf), "%i", getpid());
+	write_string_to_file(cgroup_file, buf);
+
+	// deny by default
+	must_snprintf(cgroup_file, sizeof(cgroup_file), "%s%s", cgroup_dir,
+		      "devices.deny");
+	write_string_to_file(cgroup_file, "a");
+
+}
+
+bool snappy_udev_setup_required(const char *appname)
+{
+	debug("snappy_udev_setup_required");
+
+	// extra paranoia
+	if (!verify_appname(appname))
+		die("appname %s not allowed", appname);
+
+	char override_file[PATH_MAX];
+	must_snprintf(override_file, sizeof(override_file),
+		      "/var/lib/apparmor/clicks/%s.json.additional", appname);
+
+	// if a snap package gets unrestricted apparmor access we need to setup
+	// a device cgroup.
+	//
+	// the "needle" string is what gives this access so we search for that
+	// here
+	const char *needle =
+	    "{" "\n"
+	    " \"write_path\": [" "\n"
+	    "   \"/dev/**\"" "\n"
+	    " ]," "\n"
+	    " \"read_path\": [" "\n" "   \"/run/udev/data/*\"" "\n" " ]\n" "}";
+	debug("looking for: '%s'", needle);
+	char content[strlen(needle)];
+
+	int fd = open(override_file, O_CLOEXEC | O_NOFOLLOW | O_RDONLY);
+	if (fd < 0)
+		return false;
+	int n = read(fd, content, sizeof(content));
+	close(fd);
+	if (n < sizeof(content))
+		return false;
+
+	// memcpy so that we don't have to deal with \0 in the input
+	if (memcmp(content, needle, strlen(needle)) == 0) {
+		debug("found needle, need to apply udev setup");
+		return true;
+	}
+
+	return false;
+}
+
+bool is_running_on_classic_ubuntu()
+{
+	return (access("/var/lib/dpkg/status", F_OK) == 0);
+}
+
+void setup_private_mount(const char *appname)
+{
+	uid_t uid = getuid();
+	gid_t gid = getgid();
+	char tmpdir[MAX_BUF] = { 0 };
+
+	// Create a 0700 base directory, this is the base dir that is
+	// protected from other users.
+	//
+	// Under that basedir, we put a 1777 /tmp dir that is then bind
+	// mounted for the applications to use
+	must_snprintf(tmpdir, sizeof(tmpdir), "/tmp/snap.%d_%s_XXXXXX", uid,
+		      appname);
+	if (mkdtemp(tmpdir) == NULL) {
+		die("unable to create tmpdir");
+	}
+	// now we create a 1777 /tmp inside our private dir
+	mode_t old_mask = umask(0);
+	char *d = strdup(tmpdir);
+	if (!d) {
+		die("Out of memory");
+	}
+	must_snprintf(tmpdir, sizeof(tmpdir), "%s/tmp", d);
+	free(d);
+
+	if (mkdir(tmpdir, 01777) != 0) {
+		die("unable to create /tmp inside private dir");
+	}
+	umask(old_mask);
+
+	// MS_BIND is there from linux 2.4
+	if (mount(tmpdir, "/tmp", NULL, MS_BIND, NULL) != 0) {
+		die("unable to bind private /tmp");
+	}
+	// MS_PRIVATE needs linux > 2.6.11
+	if (mount("none", "/tmp", NULL, MS_PRIVATE, NULL) != 0) {
+		die("unable to make /tmp/ private");
+	}
+	// do the chown after the bind mount to avoid potential shenanigans
+	if (chown("/tmp/", uid, gid) < 0) {
+		die("unable to chown tmpdir");
+	}
+	// ensure we set the various TMPDIRs to our newly created tmpdir
+	const char *tmpd[] = { "TMPDIR", "TEMPDIR", "SNAP_APP_TMPDIR", NULL };
+	int i;
+	for (i = 0; tmpd[i] != NULL; i++) {
+		if (setenv(tmpd[i], "/tmp", 1) != 0) {
+			die("unable to set '%s'", tmpd[i]);
+		}
+	}
+}
+
+void setup_private_pts()
+{
+	// See https://www.kernel.org/doc/Documentation/filesystems/devpts.txt
+	//
+	// Ubuntu by default uses devpts 'single-instance' mode where /dev/pts/ptmx
+	// is mounted with ptmxmode=0000. We don't want to change the startup
+	// scripts though, so we follow the instructions in point '4' of
+	// 'User-space changes' in the above doc. In other words, after
+	// unshare(CLONE_NEWNS), we mount devpts with -o newinstance,ptmxmode=0666
+	// and then bind mount /dev/pts/ptmx onto /dev/ptmx
+
+	struct stat st;
+
+	// Make sure /dev/pts/ptmx exists, otherwise we are in legacy mode which
+	// doesn't provide the isolation we require.
+	if (stat("/dev/pts/ptmx", &st) != 0) {
+		die("/dev/pts/ptmx does not exist");
+	}
+	// Make sure /dev/ptmx exists so we can bind mount over it
+	if (stat("/dev/ptmx", &st) != 0) {
+		die("/dev/ptmx does not exist");
+	}
+	// Since multi-instance, use ptmxmode=0666. The other options are copied
+	// from /etc/default/devpts
+	if (mount("devpts", "/dev/pts", "devpts", MS_MGC_VAL,
+		  "newinstance,ptmxmode=0666,mode=0620,gid=5")) {
+		die("unable to mount a new instance of '/dev/pts'");
+	}
+
+	if (mount("/dev/pts/ptmx", "/dev/ptmx", "none", MS_BIND, 0)) {
+		die("unable to mount '/dev/pts/ptmx'->'/dev/ptmx'");
+	}
+}
+
+void setup_snappy_os_mounts()
+{
+	debug("setup_snappy_os_mounts()\n");
+
+	// FIXME: hardcoded "ubuntu-core.*"
+	glob_t glob_res;
+	if (glob("/snaps/ubuntu-core*/current/", 0, NULL, &glob_res) != 0) {
+		die("can not find a snappy os");
+	}
+	if ((glob_res.gl_pathc = !1)) {
+		die("expected 1 os snap, found %i", (int)glob_res.gl_pathc);
+	}
+	char *mountpoint = glob_res.gl_pathv[0];
+
+	// we mount some whitelisted directories
+	//
+	// Note that we do not mount "/etc/" from snappy. We could do that,
+	// but if we do we need to ensure that data like /etc/{hostname,hosts,
+	// passwd,groups} is in sync between the two systems (probably via
+	// selected bind mounts of those files).
+	const char *mounts[] = { "/bin", "/sbin", "/lib", "/lib64", "/usr" };
+	for (int i = 0; i < sizeof(mounts) / sizeof(char *); i++) {
+		// we mount the OS snap /bin over the real /bin in this NS
+		const char *dst = mounts[i];
+
+		char buf[512];
+		must_snprintf(buf, sizeof(buf), "%s%s", mountpoint, dst);
+		const char *src = buf;
+
+		debug("mounting %s -> %s\n", src, dst);
+		if (mount(src, dst, NULL, MS_BIND, NULL) != 0) {
+			die("unable to bind %s to %s", src, dst);
+		}
+	}
+
+	globfree(&glob_res);
+}
+
+void setup_slave_mount_namespace()
+{
+	// unshare() and CLONE_NEWNS require linux >= 2.6.16 and glibc >= 2.14
+	// if using an older glibc, you'd need -D_BSD_SOURCE or -D_SVID_SORUCE.
+	if (unshare(CLONE_NEWNS) < 0) {
+		die("unable to set up mount namespace");
+	}
+	// make our "/" a rslave of the real "/". this means that
+	// mounts from the host "/" get propagated to our namespace
+	// (i.e. we see new media mounts)
+	if (mount("none", "/", NULL, MS_REC | MS_SLAVE, NULL) != 0) {
+		die("can not make make / rslave");
+	}
+}
+
+void mkpath(const char *const path)
+{
+	// If asked to create an empty path, return immediately.
+	if (strlen(path) == 0) {
+		return;
+	}
+	// We're going to use strtok_r, which needs to modify the path, so we'll make
+	// a copy of it.
+	char *path_copy = strdup(path);
+	if (path_copy == NULL) {
+		die("failed to create user data directory");
+	}
+	// Open flags to use while we walk the user data path:
+	// - Don't follow symlinks
+	// - Don't allow child access to file descriptor
+	// - Only open a directory (fail otherwise)
+	int open_flags = O_NOFOLLOW | O_CLOEXEC | O_DIRECTORY;
+
+	// We're going to create each path segment via openat/mkdirat calls instead
+	// of mkdir calls, to avoid following symlinks and placing the user data
+	// directory somewhere we never intended for it to go. The first step is to
+	// get an initial file descriptor.
+	int fd = AT_FDCWD;
+	if (path_copy[0] == '/') {
+		fd = open("/", open_flags);
+		if (fd < 0) {
+			free(path_copy);
+			die("failed to create user data directory");
+		}
+	}
+	// strtok_r needs a pointer to keep track of where it is in the string.
+	char *path_walker;
+
+	// Initialize tokenizer and obtain first path segment.
+	char *path_segment = strtok_r(path_copy, "/", &path_walker);
+	while (path_segment) {
+		// Try to create the directory. It's okay if it already existed, but any
+		// other error is fatal.
+		if (mkdirat(fd, path_segment, 0755) < 0 && errno != EEXIST) {
+			close(fd);
+			free(path_copy);
+			die("failed to create user data directory");
+		}
+		// Open the parent directory we just made (and close the previous one) so
+		// we can continue down the path.
+		int previous_fd = fd;
+		fd = openat(fd, path_segment, open_flags);
+		close(previous_fd);
+		if (fd < 0) {
+			free(path_copy);
+			die("failed to create user data directory");
+		}
+		// Obtain the next path segment.
+		path_segment = strtok_r(NULL, "/", &path_walker);
+	}
+
+	// Close the descriptor for the final directory in the path.
+	close(fd);
+
+	free(path_copy);
+}
+
+void setup_user_data()
+{
+	const char *user_data = getenv("SNAP_USER_DATA");
+
+	// If $SNAP_USER_DATA wasn't defined, check the deprecated
+	// $SNAP_APP_USER_DATA_PATH.
+	if (user_data == NULL) {
+		user_data = getenv("SNAP_APP_USER_DATA_PATH");
+		// If it's still not defined, there's nothing to do. No need to die,
+		// there's simply no directory to create.
+		if (user_data == NULL) {
+			return;
+		}
+	}
+	// Only support absolute paths.
+	if (user_data[0] != '/') {
+		die("user data directory must be an absolute path");
+	}
+
+	mkpath(user_data);
 }
 
 int main(int argc, char **argv)
 {
-   const int NR_ARGS = 3;
-   if(argc < NR_ARGS+1)
-      die("Usage: %s <appname> <apparmor> <binary>", argv[0]);
-
-   const char *appname = argv[1];
-   const char *aa_profile = argv[2];
-   const char *binary = argv[3];
-   unsigned real_uid = getuid();
-   unsigned real_gid = getgid();
-
-   if(!verify_appname(appname))
-      die("appname %s not allowed", appname);
-
-   // this code always needs to run as root for the cgroup/udev setup,
-   // however for the tests we allow it to run as non-root
-   if(geteuid() != 0 && getenv("UBUNTU_CORE_LAUNCHER_NO_ROOT") == NULL) {
-      die("need to run as root or suid");
-   }
-
-   if(geteuid() == 0) {
-
-      // ensure we run in our own slave mount namespace, this will
-      // create a new mount namespace and make it a slave of "/"
-      //
-      // Note that this means that no mount actions inside our
-      // namespace are propagated to the main "/". We need this
-      // both for the private /tmp we create and for the bind
-      // mounts we do on a classic ubuntu system
-      //
-      // This also means you can't run an automount daemon unter
-      // this launcher
-      setup_slave_mount_namespace();
-
-      // do the mounting if run on a non-native snappy system
-      if(is_running_on_classic_ubuntu()) {
-         setup_snappy_os_mounts();
-      }
-
-      // set up private mounts
-      setup_private_mount(appname);
-
-      // set up private /dev/pts
-      setup_private_pts();
-
-      // this needs to happen as root
-      if(snappy_udev_setup_required(appname)) {
-         setup_devices_cgroup(appname);
-         setup_udev_snappy_assign(appname);
-      }
-
-      // the rest does not so temporarily drop privs back to calling user
-      // (we'll permanently drop after loading seccomp)
-      if (setegid(real_gid) != 0)
-         die("setegid failed");
-      if (seteuid(real_uid) != 0)
-         die("seteuid failed");
-
-      if(real_gid != 0 && geteuid() == 0)
-         die("dropping privs did not work");
-      if(real_uid != 0 && getegid() == 0)
-         die("dropping privs did not work");
-   }
-
-   // Ensure that the user data path exists.
-   setup_user_data();
-
-   // https://wiki.ubuntu.com/SecurityTeam/Specifications/SnappyConfinement
-
-   int rc = 0;
-   // set apparmor rules
-   rc = aa_change_onexec(aa_profile);
-   if (rc != 0) {
-   if (getenv("SNAPPY_LAUNCHER_INSIDE_TESTS") == NULL)
-      die("aa_change_onexec failed with %i", rc);
-   }
-
-   // set seccomp
-   rc = seccomp_load_filters(aa_profile);
-   if (rc != 0)
-      die("seccomp_load_filters failed with %i", rc);
-
-   // Permanently drop if not root
-   if (geteuid() == 0) {
-      // Note that we do not call setgroups() here because its ok
-      // that the user keeps the groups he already belongs to
-      if (setgid(real_gid) != 0)
-         die("setgid failed");
-      if (setuid(real_uid) != 0)
-         die("setuid failed");
-
-      if(real_gid != 0 && (getuid() == 0 || geteuid() == 0))
-         die("permanently dropping privs did not work");
-      if(real_uid != 0 && (getgid() == 0 || getegid() == 0))
-         die("permanently dropping privs did not work");
-   }
-
-   // and exec the new binary
-   argv[NR_ARGS] = (char*)binary,
-   execv(binary, (char *const*)&argv[NR_ARGS]);
-   perror("execv failed");
-   return 1;
+	const int NR_ARGS = 3;
+	if (argc < NR_ARGS + 1)
+		die("Usage: %s <appname> <apparmor> <binary>", argv[0]);
+
+	const char *appname = argv[1];
+	const char *aa_profile = argv[2];
+	const char *binary = argv[3];
+	unsigned real_uid = getuid();
+	unsigned real_gid = getgid();
+
+	if (!verify_appname(appname))
+		die("appname %s not allowed", appname);
+
+	// this code always needs to run as root for the cgroup/udev setup,
+	// however for the tests we allow it to run as non-root
+	if (geteuid() != 0 && getenv("UBUNTU_CORE_LAUNCHER_NO_ROOT") == NULL) {
+		die("need to run as root or suid");
+	}
+
+	if (geteuid() == 0) {
+
+		// ensure we run in our own slave mount namespace, this will
+		// create a new mount namespace and make it a slave of "/"
+		//
+		// Note that this means that no mount actions inside our
+		// namespace are propagated to the main "/". We need this
+		// both for the private /tmp we create and for the bind
+		// mounts we do on a classic ubuntu system
+		//
+		// This also means you can't run an automount daemon unter
+		// this launcher
+		setup_slave_mount_namespace();
+
+		// do the mounting if run on a non-native snappy system
+		if (is_running_on_classic_ubuntu()) {
+			setup_snappy_os_mounts();
+		}
+		// set up private mounts
+		setup_private_mount(appname);
+
+		// set up private /dev/pts
+		setup_private_pts();
+
+		// this needs to happen as root
+		if (snappy_udev_setup_required(appname)) {
+			setup_devices_cgroup(appname);
+			setup_udev_snappy_assign(appname);
+		}
+		// the rest does not so temporarily drop privs back to calling user
+		// (we'll permanently drop after loading seccomp)
+		if (setegid(real_gid) != 0)
+			die("setegid failed");
+		if (seteuid(real_uid) != 0)
+			die("seteuid failed");
+
+		if (real_gid != 0 && geteuid() == 0)
+			die("dropping privs did not work");
+		if (real_uid != 0 && getegid() == 0)
+			die("dropping privs did not work");
+	}
+	// Ensure that the user data path exists.
+	setup_user_data();
+
+	// https://wiki.ubuntu.com/SecurityTeam/Specifications/SnappyConfinement
+
+	int rc = 0;
+	// set apparmor rules
+	rc = aa_change_onexec(aa_profile);
+	if (rc != 0) {
+		if (getenv("SNAPPY_LAUNCHER_INSIDE_TESTS") == NULL)
+			die("aa_change_onexec failed with %i", rc);
+	}
+	// set seccomp
+	rc = seccomp_load_filters(aa_profile);
+	if (rc != 0)
+		die("seccomp_load_filters failed with %i", rc);
+
+	// Permanently drop if not root
+	if (geteuid() == 0) {
+		// Note that we do not call setgroups() here because its ok
+		// that the user keeps the groups he already belongs to
+		if (setgid(real_gid) != 0)
+			die("setgid failed");
+		if (setuid(real_uid) != 0)
+			die("setuid failed");
+
+		if (real_gid != 0 && (getuid() == 0 || geteuid() == 0))
+			die("permanently dropping privs did not work");
+		if (real_uid != 0 && (getgid() == 0 || getegid() == 0))
+			die("permanently dropping privs did not work");
+	}
+	// and exec the new binary
+	argv[NR_ARGS] = (char *)binary,
+	    execv(binary, (char *const *)&argv[NR_ARGS]);
+	perror("execv failed");
+	return 1;
 }
 
=== modified file 'src/seccomp.c'
--- src/seccomp.c	2016-03-21 17:22:39 +0000
+++ src/seccomp.c	2016-03-22 12:19:24 +0000
@@ -29,133 +29,140 @@
 char *filter_profile_dir = "/var/lib/snappy/seccomp/profiles/";
 
 // strip whitespace from the end of the given string (inplace)
-size_t trim_right(char *s, size_t slen) {
-   while(slen > 0 && isspace(s[slen - 1])) {
-      s[--slen] = 0;
-   }
-   return slen;
+size_t trim_right(char *s, size_t slen)
+{
+	while (slen > 0 && isspace(s[slen - 1])) {
+		s[--slen] = 0;
+	}
+	return slen;
 }
 
 int seccomp_load_filters(const char *filter_profile)
 {
-   debug("seccomp_load_filters %s", filter_profile);
-   int rc = 0;
-   int syscall_nr = -1;
-   scmp_filter_ctx ctx = NULL;
-   FILE *f = NULL;
-   size_t lineno = 0;
-
-   ctx = seccomp_init(SCMP_ACT_KILL);
-   if (ctx == NULL)
-      return ENOMEM;
-
-   // Disable NO_NEW_PRIVS because it interferes with exec transitions in
-   // AppArmor. Unfortunately this means that security policies must be very
-   // careful to not allow the following otherwise apps can escape the snadbox:
-   //   - seccomp syscall
-   //   - prctl with PR_SET_SECCOMP
-   //   - ptrace (trace) in AppArmor
-   //   - capability sys_admin in AppArmor
-   // Note that with NO_NEW_PRIVS disabled, CAP_SYS_ADMIN is required to change
-   // the seccomp sandbox.
-   if (getenv("UBUNTU_CORE_LAUNCHER_NO_ROOT") == NULL) {
-      rc = seccomp_attr_set(ctx, SCMP_FLTATR_CTL_NNP, 0);
-      if (rc != 0) {
-         fprintf(stderr, "Cannot disable nnp\n");
-         return -1;
-      }
-   }
-
-   if (getenv("SNAPPY_LAUNCHER_SECCOMP_PROFILE_DIR") != NULL)
-      filter_profile_dir = getenv("SNAPPY_LAUNCHER_SECCOMP_PROFILE_DIR");
-
-   char profile_path[128];
-   if (snprintf(profile_path, sizeof(profile_path), "%s/%s", filter_profile_dir, filter_profile) < 0) {
-      goto out;
-   }
-
-   f = fopen(profile_path, "r");
-   if (f == NULL) {
-      fprintf(stderr, "Can not open %s (%s)\n", profile_path, strerror(errno));
-      return -1;
-   }
-   // 80 characters + '\n' + '\0'
-   char buf[82];
-   while (fgets(buf, sizeof(buf), f) != NULL)
-   {
-      size_t len;
-
-      lineno++;
-
-      // comment, ignore
-      if(buf[0] == '#')
-         continue;
-
-      // ensure the entire line was read
-      len = strlen(buf);
-      if (len == 0)
-         continue;
-      else if (buf[len - 1] != '\n' && len > (sizeof(buf) - 2)) {
-         fprintf(stderr, "seccomp filter line %zu was too long (%zu characters max)\n", lineno, sizeof(buf) - 2);
-         rc = -1;
-         goto out;
-      }
-
-      // kill final newline
-      len = trim_right(buf, len);
-      if (len == 0)
-         continue;
-
-      // check for special "@unrestricted" command
-      if (strncmp(buf, "@unrestricted", sizeof(buf)) == 0)
-         goto out;
-
-      // syscall not available on this arch/kernel
-      // as this is a syscall whitelist its ok and the error can be ignored
-      syscall_nr = seccomp_syscall_resolve_name(buf);
-      if (syscall_nr == __NR_SCMP_ERROR)
-         continue;
-
-      // a normal line with a syscall
-      rc = seccomp_rule_add_exact(ctx, SCMP_ACT_ALLOW, syscall_nr, 0);
-      if (rc != 0) {
-         rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, syscall_nr, 0);
-	 if (rc != 0) {
-             fprintf(stderr, "seccomp_rule_add failed with %i for '%s'\n", rc, buf);
-             goto out;
-	 }
-      }
-   }
-
-   // raise privileges to load seccomp policy since we don't have nnp
-   if (getenv("UBUNTU_CORE_LAUNCHER_NO_ROOT") == NULL) {
-      if (seteuid(0) != 0)
-         die("seteuid failed");
-      if (geteuid() != 0)
-         die("raising privs before seccomp_load did not work");
-   }
-
-   // load it into the kernel
-   rc = seccomp_load(ctx);
-
-   if (rc != 0) {
-      fprintf(stderr, "seccomp_load failed with %i\n", rc);
-      goto out;
-   }
+	debug("seccomp_load_filters %s", filter_profile);
+	int rc = 0;
+	int syscall_nr = -1;
+	scmp_filter_ctx ctx = NULL;
+	FILE *f = NULL;
+	size_t lineno = 0;
+
+	ctx = seccomp_init(SCMP_ACT_KILL);
+	if (ctx == NULL)
+		return ENOMEM;
+
+	// Disable NO_NEW_PRIVS because it interferes with exec transitions in
+	// AppArmor. Unfortunately this means that security policies must be very
+	// careful to not allow the following otherwise apps can escape the snadbox:
+	//   - seccomp syscall
+	//   - prctl with PR_SET_SECCOMP
+	//   - ptrace (trace) in AppArmor
+	//   - capability sys_admin in AppArmor
+	// Note that with NO_NEW_PRIVS disabled, CAP_SYS_ADMIN is required to change
+	// the seccomp sandbox.
+	if (getenv("UBUNTU_CORE_LAUNCHER_NO_ROOT") == NULL) {
+		rc = seccomp_attr_set(ctx, SCMP_FLTATR_CTL_NNP, 0);
+		if (rc != 0) {
+			fprintf(stderr, "Cannot disable nnp\n");
+			return -1;
+		}
+	}
+
+	if (getenv("SNAPPY_LAUNCHER_SECCOMP_PROFILE_DIR") != NULL)
+		filter_profile_dir =
+		    getenv("SNAPPY_LAUNCHER_SECCOMP_PROFILE_DIR");
+
+	char profile_path[128];
+	if (snprintf
+	    (profile_path, sizeof(profile_path), "%s/%s", filter_profile_dir,
+	     filter_profile) < 0) {
+		goto out;
+	}
+
+	f = fopen(profile_path, "r");
+	if (f == NULL) {
+		fprintf(stderr, "Can not open %s (%s)\n", profile_path,
+			strerror(errno));
+		return -1;
+	}
+	// 80 characters + '\n' + '\0'
+	char buf[82];
+	while (fgets(buf, sizeof(buf), f) != NULL) {
+		size_t len;
+
+		lineno++;
+
+		// comment, ignore
+		if (buf[0] == '#')
+			continue;
+
+		// ensure the entire line was read
+		len = strlen(buf);
+		if (len == 0)
+			continue;
+		else if (buf[len - 1] != '\n' && len > (sizeof(buf) - 2)) {
+			fprintf(stderr,
+				"seccomp filter line %zu was too long (%zu characters max)\n",
+				lineno, sizeof(buf) - 2);
+			rc = -1;
+			goto out;
+		}
+		// kill final newline
+		len = trim_right(buf, len);
+		if (len == 0)
+			continue;
+
+		// check for special "@unrestricted" command
+		if (strncmp(buf, "@unrestricted", sizeof(buf)) == 0)
+			goto out;
+
+		// syscall not available on this arch/kernel
+		// as this is a syscall whitelist its ok and the error can be ignored
+		syscall_nr = seccomp_syscall_resolve_name(buf);
+		if (syscall_nr == __NR_SCMP_ERROR)
+			continue;
+
+		// a normal line with a syscall
+		rc = seccomp_rule_add_exact(ctx, SCMP_ACT_ALLOW, syscall_nr, 0);
+		if (rc != 0) {
+			rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, syscall_nr,
+					      0);
+			if (rc != 0) {
+				fprintf(stderr,
+					"seccomp_rule_add failed with %i for '%s'\n",
+					rc, buf);
+				goto out;
+			}
+		}
+	}
+
+	// raise privileges to load seccomp policy since we don't have nnp
+	if (getenv("UBUNTU_CORE_LAUNCHER_NO_ROOT") == NULL) {
+		if (seteuid(0) != 0)
+			die("seteuid failed");
+		if (geteuid() != 0)
+			die("raising privs before seccomp_load did not work");
+	}
+	// load it into the kernel
+	rc = seccomp_load(ctx);
+
+	if (rc != 0) {
+		fprintf(stderr, "seccomp_load failed with %i\n", rc);
+		goto out;
+	}
 
  out:
-   // drop privileges again
-   if (geteuid() == 0) {
-      unsigned real_uid = getuid();
-      if (seteuid(real_uid) != 0)
-         die("seteuid failed");
-      if (real_uid != 0 && geteuid() == 0)
-         die("dropping privs after seccomp_load did not work");
-   }
+	// drop privileges again
+	if (geteuid() == 0) {
+		unsigned real_uid = getuid();
+		if (seteuid(real_uid) != 0)
+			die("seteuid failed");
+		if (real_uid != 0 && geteuid() == 0)
+			die("dropping privs after seccomp_load did not work");
+	}
 
-   if (f != NULL) {
-      fclose(f);
-   }
-   seccomp_release(ctx);
-   return rc;
+	if (f != NULL) {
+		fclose(f);
+	}
+	seccomp_release(ctx);
+	return rc;
 }
 
=== modified file 'src/utils.c'
--- src/utils.c	2015-06-11 10:57:01 +0000
+++ src/utils.c	2016-03-22 12:19:24 +0000
@@ -24,64 +24,66 @@
 
 void die(const char *msg, ...)
 {
-   va_list va;
-   va_start(va, msg);
-   vfprintf(stderr, msg, va);
-   va_end(va);
+	va_list va;
+	va_start(va, msg);
+	vfprintf(stderr, msg, va);
+	va_end(va);
 
-   if (errno != 0) {
-     perror(". errmsg");
-   } else {
-     fprintf(stderr, "\n");
-   }
-   exit(1);
+	if (errno != 0) {
+		perror(". errmsg");
+	} else {
+		fprintf(stderr, "\n");
+	}
+	exit(1);
 }
 
 bool error(const char *msg, ...)
 {
-   va_list va;
-   va_start(va, msg);
-   vfprintf(stderr, msg, va);
-   va_end(va);
+	va_list va;
+	va_start(va, msg);
+	vfprintf(stderr, msg, va);
+	va_end(va);
 
-   return false;
+	return false;
 }
 
 void debug(const char *msg, ...)
 {
-   if(getenv("UBUNTU_CORE_LAUNCHER_DEBUG") == NULL)
-      return;
-
-   va_list va;
-   va_start(va, msg);
-   fprintf(stderr, "DEBUG: ");
-   vfprintf(stderr, msg, va);
-   fprintf(stderr, "\n");
-   va_end(va);
-}
-
-void write_string_to_file(const char *filepath, const char *buf) {
-   debug("write_string_to_file %s %s", filepath, buf);
-   FILE *f = fopen(filepath, "w");
-   if (f == NULL)
-      die("fopen %s failed", filepath);
-   if (fwrite(buf, strlen(buf), 1, f) != 1)
-      die("fwrite failed");
-   if (fflush(f) != 0)
-      die("fflush failed");
-   fclose(f);
-}
-
-int must_snprintf(char *str, size_t size, const char *format, ...) {
-   int n = -1;
-
-   va_list va;
-   va_start(va, format);
-   n = vsnprintf(str, size, format, va);
-   va_end(va);
-
-   if(n < 0 || n >= size)
-      die("failed to snprintf %s", str);
-
-   return n;
+	if (getenv("UBUNTU_CORE_LAUNCHER_DEBUG") == NULL)
+		return;
+
+	va_list va;
+	va_start(va, msg);
+	fprintf(stderr, "DEBUG: ");
+	vfprintf(stderr, msg, va);
+	fprintf(stderr, "\n");
+	va_end(va);
+}
+
+void write_string_to_file(const char *filepath, const char *buf)
+{
+	debug("write_string_to_file %s %s", filepath, buf);
+	FILE *f = fopen(filepath, "w");
+	if (f == NULL)
+		die("fopen %s failed", filepath);
+	if (fwrite(buf, strlen(buf), 1, f) != 1)
+		die("fwrite failed");
+	if (fflush(f) != 0)
+		die("fflush failed");
+	fclose(f);
+}
+
+int must_snprintf(char *str, size_t size, const char *format, ...)
+{
+	int n = -1;
+
+	va_list va;
+	va_start(va, format);
+	n = vsnprintf(str, size, format, va);
+	va_end(va);
+
+	if (n < 0 || n >= size)
+		die("failed to snprintf %s", str);
+
+	return n;
 }
 
=== modified file 'src/utils.h'
--- src/utils.h	2015-05-20 11:10:29 +0000
+++ src/utils.h	2016-03-22 12:19:24 +0000
@@ -20,19 +20,19 @@
 #define CORE_LAUNCHER_UTILS_H
 
 __attribute__ ((noreturn))
-__attribute__ ((format (printf, 1, 2)))
+    __attribute__ ((format(printf, 1, 2)))
 void die(const char *fmt, ...);
 
-__attribute__ ((format (printf, 1, 2)))
+__attribute__ ((format(printf, 1, 2)))
 bool error(const char *fmt, ...);
 
-__attribute__ ((format (printf, 1, 2)))
+__attribute__ ((format(printf, 1, 2)))
 void debug(const char *fmt, ...);
 
 void write_string_to_file(const char *filepath, const char *buf);
 
 // snprintf version that dies on any error condition
-__attribute__ ((format (printf, 3, 4)))
+__attribute__ ((format(printf, 3, 4)))
 int must_snprintf(char *str, size_t size, const char *format, ...);
 
 #endif