/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2010 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <sys/mount.h> #include <errno.h> #include <sys/stat.h> #include <stdlib.h> #include <string.h> #include <libgen.h> #include <assert.h> #include <unistd.h> #include <ftw.h> #include "mount-setup.h" #include "log.h" #include "macro.h" #include "util.h" #include "label.h" #include "set.h" #include "strv.h" #ifndef TTY_GID #define TTY_GID 5 #endif typedef struct MountPoint { const char *what; const char *where; const char *type; const char *options; unsigned long flags; bool fatal; } MountPoint; /* The first three entries we might need before SELinux is up. The * fourth (securityfs) is needed by IMA to load a custom policy. The * other ones we can delay until SELinux and IMA are loaded. */ #define N_EARLY_MOUNT 4 static const MountPoint mount_table[] = { { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true }, { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true }, { "devtmpfs", "/dev", "devtmpfs", "mode=755", MS_NOSUID, true }, { "securityfs", "/sys/kernel/security", "securityfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, false }, { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV, true }, { "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC, false }, { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV, true }, { "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV, false }, { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID|MS_NOEXEC|MS_NODEV, false }, }; /* These are API file systems that might be mounted by other software, * we just list them here so that we know that we should ignore them */ static const char * const ignore_paths[] = { "/sys/fs/selinux", "/selinux", "/proc/bus/usb" }; bool mount_point_is_api(const char *path) { unsigned i; /* Checks if this mount point is considered "API", and hence * should be ignored */ for (i = 0; i < ELEMENTSOF(mount_table); i ++) if (path_equal(path, mount_table[i].where)) return true; return path_startswith(path, "/sys/fs/cgroup/"); } bool mount_point_ignore(const char *path) { unsigned i; for (i = 0; i < ELEMENTSOF(ignore_paths); i++) if (path_equal(path, ignore_paths[i])) return true; return false; } static int mount_one(const MountPoint *p, bool relabel) { int r; assert(p); /* Relabel first, just in case */ if (relabel) label_fix(p->where, true); if ((r = path_is_mount_point(p->where, true)) < 0) return r; if (r > 0) return 0; /* The access mode here doesn't really matter too much, since * the mounted file system will take precedence anyway. */ mkdir_p(p->where, 0755); log_debug("Mounting %s to %s of type %s with options %s.", p->what, p->where, p->type, strna(p->options)); if (mount(p->what, p->where, p->type, p->flags, p->options) < 0) { log_error("Failed to mount %s: %s", p->where, strerror(errno)); return p->fatal ? -errno : 0; } /* Relabel again, since we now mounted something fresh here */ if (relabel) label_fix(p->where, false); return 1; } int mount_setup_early(void) { unsigned i; int r = 0; assert_cc(N_EARLY_MOUNT <= ELEMENTSOF(mount_table)); /* Do a minimal mount of /proc and friends to enable the most * basic stuff, such as SELinux */ for (i = 0; i < N_EARLY_MOUNT; i ++) { int j; j = mount_one(mount_table + i, false); if (r == 0) r = j; } return r; } int mount_cgroup_controllers(char ***join_controllers) { int r; FILE *f; char buf[LINE_MAX]; Set *controllers; /* Mount all available cgroup controllers that are built into the kernel. */ f = fopen("/proc/cgroups", "re"); if (!f) { log_error("Failed to enumerate cgroup controllers: %m"); return 0; } controllers = set_new(string_hash_func, string_compare_func); if (!controllers) { r = -ENOMEM; log_error("Failed to allocate controller set."); goto finish; } /* Ignore the header line */ (void) fgets(buf, sizeof(buf), f); for (;;) { char *controller; int enabled = 0; if (fscanf(f, "%ms %*i %*i %i", &controller, &enabled) != 2) { if (feof(f)) break; log_error("Failed to parse /proc/cgroups."); r = -EIO; goto finish; } if (!enabled) { free(controller); continue; } r = set_put(controllers, controller); if (r < 0) { log_error("Failed to add controller to set."); free(controller); goto finish; } } for (;;) { MountPoint p; char *controller, *where, *options; char ***k = NULL; controller = set_steal_first(controllers); if (!controller) break; if (join_controllers) for (k = join_controllers; *k; k++) if (strv_find(*k, controller)) break; if (k && *k) { char **i, **j; for (i = *k, j = *k; *i; i++) { if (!streq(*i, controller)) { char *t; t = set_remove(controllers, *i); if (!t) { free(*i); continue; } free(t); } *(j++) = *i; } *j = NULL; options = strv_join(*k, ","); if (!options) { log_error("Failed to join options"); free(controller); r = -ENOMEM; goto finish; } } else { options = controller; controller = NULL; } where = strappend("/sys/fs/cgroup/", options); if (!where) { log_error("Failed to build path"); free(options); r = -ENOMEM; goto finish; } zero(p); p.what = "cgroup"; p.where = where; p.type = "cgroup"; p.options = options; p.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV; p.fatal = false; r = mount_one(&p, true); free(controller); free(where); if (r < 0) { free(options); goto finish; } if (r > 0 && k && *k) { char **i; for (i = *k; *i; i++) { char *t; t = strappend("/sys/fs/cgroup/", *i); if (!t) { log_error("Failed to build path"); r = -ENOMEM; free(options); goto finish; } r = symlink(options, t); free(t); if (r < 0 && errno != EEXIST) { log_error("Failed to create symlink: %m"); r = -errno; free(options); goto finish; } } } free(options); } r = 0; finish: set_free_free(controllers); fclose(f); return r; } static int symlink_and_label(const char *old_path, const char *new_path) { int r; assert(old_path); assert(new_path); if ((r = label_symlinkfile_set(new_path)) < 0) return r; if (symlink(old_path, new_path) < 0) r = -errno; label_file_clear(); return r; } static int nftw_cb( const char *fpath, const struct stat *sb, int tflag, struct FTW *ftwbuf) { /* No need to label /dev twice in a row... */ if (_unlikely_(ftwbuf->level == 0)) return FTW_CONTINUE; label_fix(fpath, true); /* /run/initramfs is static data and big, no need to * dynamically relabel its contents at boot... */ if (_unlikely_(ftwbuf->level == 1 && tflag == FTW_D && streq(fpath, "/run/initramfs"))) return FTW_SKIP_SUBTREE; return FTW_CONTINUE; }; int mount_setup(bool loaded_policy) { static const char symlinks[] = "/proc/kcore\0" "/dev/core\0" "/proc/self/fd\0" "/dev/fd\0" "/proc/self/fd/0\0" "/dev/stdin\0" "/proc/self/fd/1\0" "/dev/stdout\0" "/proc/self/fd/2\0" "/dev/stderr\0"; static const char relabel[] = "/run/initramfs/root-fsck\0" "/run/initramfs/shutdown\0"; int r; unsigned i; const char *j, *k; for (i = 0; i < ELEMENTSOF(mount_table); i ++) { r = mount_one(mount_table + i, true); if (r < 0) return r; } /* Nodes in devtmpfs and /run need to be manually updated for * the appropriate labels, after mounting. The other virtual * API file systems like /sys and /proc do not need that, they * use the same label for all their files. */ if (loaded_policy) { usec_t before_relabel, after_relabel; char timespan[FORMAT_TIMESPAN_MAX]; before_relabel = now(CLOCK_MONOTONIC); nftw("/dev", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL); nftw("/run", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL); /* Explicitly relabel these */ NULSTR_FOREACH(j, relabel) label_fix(j, true); after_relabel = now(CLOCK_MONOTONIC); log_info("Relabelled /dev and /run in %s.", format_timespan(timespan, sizeof(timespan), after_relabel - before_relabel)); } /* Create a few default symlinks, which are normally created * by udevd, but some scripts might need them before we start * udevd. */ NULSTR_FOREACH_PAIR(j, k, symlinks) symlink_and_label(j, k); /* Create a few directories we always want around */ label_mkdir("/run/systemd", 0755); label_mkdir("/run/systemd/system", 0755); return 0; }