X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fmount-setup.c;h=abb0c19d2543e110478831b5ee9a5e944497b87f;hp=e4f2b73faafa6badcf3fa54e10bf2a7e0c01b16d;hb=0c85a4f3efa2883c414ed8ff59aea263b85b7687;hpb=53f7d807bff9c39e9e565ad2fb20f29b4306af40 diff --git a/src/mount-setup.c b/src/mount-setup.c index e4f2b73fa..abb0c19d2 100644 --- a/src/mount-setup.c +++ b/src/mount-setup.c @@ -1,4 +1,4 @@ -/*-*- Mode: C; c-basic-offset: 8 -*-*/ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. @@ -26,11 +26,20 @@ #include #include #include +#include +#include #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; @@ -41,16 +50,28 @@ typedef struct MountPoint { bool fatal; } MountPoint; +/* The first three entries we might need before SELinux is up. The + * other ones we can delay until SELinux is loaded. */ +#define N_EARLY_MOUNT 3 + 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 }, - { "devtmps", "/dev", "devtmpfs", "mode=755", MS_NOSUID, true }, - { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NOEXEC|MS_NODEV, true }, - { "devpts", "/dev/pts", "devpts", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, false }, - { "cgroup", "/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID|MS_NOEXEC|MS_NODEV, true }, - { "debugfs", "/sys/kernel/debug", "debugfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, false }, - { "binfmt_misc", "/proc/sys/fs/binfmt_misc", "binfmt_misc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, false }, - { "mqueue", "/dev/mqueue", "mqueue", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, false }, + { "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 }, + { "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) { @@ -60,18 +81,32 @@ bool mount_point_is_api(const char *path) { * should be ignored */ for (i = 0; i < ELEMENTSOF(mount_table); i ++) - if (path_startswith(path, mount_table[i].where)) + 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 path_startswith(path, "/cgroup/"); + return false; } -static int mount_one(const MountPoint *p) { +static int mount_one(const MountPoint *p, bool relabel) { int r; assert(p); - if ((r = path_is_mount_point(p->where)) < 0) + /* 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) @@ -96,27 +131,61 @@ static int mount_one(const MountPoint *p) { return p->fatal ? -errno : 0; } - return 0; + /* Relabel again, since we now mounted something fresh here */ + if (relabel) + label_fix(p->where, false); + + return 1; } -static int mount_cgroup_controllers(void) { +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 [256]; + char buf[LINE_MAX]; + Set *controllers; - /* Mount all available cgroup 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; + } - if (!(f = fopen("/proc/cgroups", "re"))) - return -ENOENT; + 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 (;;) { - MountPoint p; - char *controller, *where; + char *controller; + int enabled = 0; - if (fscanf(f, "%ms %*i %*i %*i", &controller) != 1) { + if (fscanf(f, "%ms %*i %*i %i", &controller, &enabled) != 2) { if (feof(f)) break; @@ -126,8 +195,71 @@ static int mount_cgroup_controllers(void) { goto finish; } - if (asprintf(&where, "/cgroup/%s", controller) < 0) { + 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; } @@ -136,33 +268,138 @@ static int mount_cgroup_controllers(void) { p.what = "cgroup"; p.where = where; p.type = "cgroup"; - p.options = controller; + p.options = options; p.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV; p.fatal = false; - r = mount_one(&p); + r = mount_one(&p, true); free(controller); free(where); - if (r < 0) + 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; } -int mount_setup(void) { +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 (ftwbuf->level == 0) + return 0; + + label_fix(fpath, true); + return 0; +}; + +int mount_setup(bool loaded_policy) { + + 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"; + int r; unsigned i; + const char *j, *k; - for (i = 0; i < ELEMENTSOF(mount_table); i ++) - if ((r = mount_one(mount_table+i)) < 0) + 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]; - return mount_cgroup_controllers(); + before_relabel = now(CLOCK_MONOTONIC); + + nftw("/dev", nftw_cb, 64, FTW_MOUNT|FTW_PHYS); + nftw("/run", nftw_cb, 64, FTW_MOUNT|FTW_PHYS); + + 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 */ + mkdir("/run/systemd", 0755); + mkdir("/run/systemd/system", 0755); + + return 0; }