/* lxcfs
*
- * Copyright © 2014 Canonical, Inc
+ * Copyright © 2014-2016 Canonical, Inc
* Author: Serge Hallyn <serge.hallyn@ubuntu.com>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2, as
- * published by the Free Software Foundation.
- *
- * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ * See COPYING file for details.
*/
-/*
- * NOTES - make sure to run this as -s to avoid threading.
- * TODO - can we enforce that here from the code?
- */
#define FUSE_USE_VERSION 26
-#include <stdio.h>
+#include <alloca.h>
#include <dirent.h>
+#include <dlfcn.h>
+#include <errno.h>
#include <fcntl.h>
#include <fuse.h>
-#include <unistd.h>
-#include <errno.h>
+#include <libgen.h>
+#include <pthread.h>
+#include <sched.h>
#include <stdbool.h>
-#include <time.h>
-#include <string.h>
+#include <stdio.h>
#include <stdlib.h>
-#include <libgen.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <wait.h>
+#include <linux/sched.h>
+#include <sys/epoll.h>
+#include <sys/mount.h>
+#include <sys/socket.h>
+#include <linux/limits.h>
-#include <nih/alloc.h>
-#include <nih/string.h>
+#include "bindings.h"
+#include "config.h" // for VERSION
-#include "cgmanager.h"
+void *dlopen_handle;
-struct lxcfs_state {
- /*
- * a null-terminated, nih-allocated list of the mounted subsystems. We
- * detect this at startup.
- */
- char **subsystems;
-};
-#define LXCFS_DATA ((struct lxcfs_state *) fuse_get_context()->private_data)
+/* Functions to keep track of number of threads using the library */
-static bool is_privileged_over(pid_t pid, uid_t uid, uid_t victim)
+static int users_count;
+static pthread_mutex_t user_count_mutex = PTHREAD_MUTEX_INITIALIZER;
+static void lock_mutex(pthread_mutex_t *l)
{
- if (uid == victim)
- return true;
-
- /* check /proc/pid/uid_map */
- return false;
-}
+ int ret;
-static bool perms_include(int fmode, mode_t req_mode)
-{
- fprintf(stderr, "perms_include: checking whether %d includes %d\n",
- fmode, req_mode);
- return (fmode & req_mode) == req_mode;
+ if ((ret = pthread_mutex_lock(l)) != 0) {
+ lxcfs_error("returned:%d %s\n", ret, strerror(ret));
+ exit(1);
+ }
}
-/*
- * check whether a fuse context may access a cgroup dir or file
- *
- * If file is not null, it is a cgroup file to check under cg.
- * If file is null, then we are checking perms on cg itself.
- *
- * For files we can check the mode of the list_keys result.
- * For cgroups, we must make assumptions based on the files under the
- * cgroup, because cgmanager doesn't tell us ownership/perms of cgroups
- * yet.
- */
-static bool fc_may_access(struct fuse_context *fc, const char *contrl, const char *cg, const char *file, mode_t mode)
+static void unlock_mutex(pthread_mutex_t *l)
{
- nih_local struct cgm_keys **list = NULL;
- int i;
+ int ret;
- if (!file)
- file = "tasks";
-
- if (*file == '/')
- file++;
-
- if (!cgm_list_keys(contrl, cg, &list))
- return false;
- for (i = 0; list[i]; i++) {
- if (strcmp(list[i]->name, file) == 0) {
- struct cgm_keys *k = list[i];
- fprintf(stderr, "XXX fc_may_access: found %s\n", file);
- // check list[i]->uid, gid, mode against fc
- if (is_privileged_over(fc->pid, fc->uid, k->uid)) {
- if (perms_include(k->mode >> 6, mode))
- return true;
- }
- if (fc->gid == k->gid) {
- if (perms_include(k->mode >> 3, mode))
- return true;
- }
- return perms_include(k->mode, mode);
- }
+ if ((ret = pthread_mutex_unlock(l)) != 0) {
+ lxcfs_error("returned:%d %s\n", ret, strerror(ret));
+ exit(1);
}
+}
- return false;
+static void users_lock(void)
+{
+ lock_mutex(&user_count_mutex);
}
-/*
- * given /cgroup/freezer/a/b, return "freezer". this will be nih-allocated
- * and needs to be nih_freed.
- */
-static char *pick_controller_from_path(struct fuse_context *fc, const char *path)
+static void users_unlock(void)
{
- const char *p1;
- char *ret, *slash;
+ unlock_mutex(&user_count_mutex);
+}
- if (strlen(path) < 9)
- return NULL;
- p1 = path+8;
- ret = nih_strdup(NULL, p1);
- if (!ret)
- return ret;
- slash = strstr(ret, "/");
- if (slash)
- *slash = '\0';
+static volatile sig_atomic_t need_reload;
- /* verify that it is a subsystem */
- char **list = LXCFS_DATA ? LXCFS_DATA->subsystems : NULL;
- int i;
- if (!list) {
- nih_free(ret);
- return NULL;
+/* do_reload - reload the dynamic library. Done under
+ * lock and when we know the user_count was 0 */
+static void do_reload(void)
+{
+ char lxcfs_lib_path[PATH_MAX];
+ if (dlopen_handle) {
+ lxcfs_debug("%s\n", "Closing liblxcfs.so handle.");
+ dlclose(dlopen_handle);
+ }
+
+ /* First try loading using ld.so */
+ dlopen_handle = dlopen("liblxcfs.so", RTLD_LAZY);
+ if (dlopen_handle) {
+ lxcfs_debug("%s\n", "Successfully called dlopen() on liblxcfs.so.");
+ goto good;
}
- for (i = 0; list[i]; i++) {
- if (strcmp(list[i], ret) == 0)
- return ret;
+
+#ifdef LIBDIR
+ /* LIBDIR: autoconf will setup this MACRO. Default value is $PREFIX/lib */
+ snprintf(lxcfs_lib_path, PATH_MAX, "%s/lxcfs/liblxcfs.so", LIBDIR);
+#else
+ snprintf(lxcfs_lib_path, PATH_MAX, "/usr/local/lib/lxcfs/liblxcfs.so");
+#endif
+ dlopen_handle = dlopen(lxcfs_lib_path, RTLD_LAZY);
+ if (!dlopen_handle) {
+ lxcfs_error("Failed to open liblxcfs.so: %s.\n", dlerror());
+ _exit(1);
}
- nih_free(ret);
- return NULL;
+
+good:
+ if (need_reload)
+ lxcfs_error("%s\n", "lxcfs: reloaded");
+ need_reload = 0;
}
-/*
- * Find the start of cgroup in /cgroup/controller/the/cgroup/path
- * Note that the returned value may include files (keynames) etc
- */
-static const char *find_cgroup_in_path(const char *path)
+static void up_users(void)
{
- const char *p1;
-
- if (strlen(path) < 9)
- return NULL;
- p1 = strstr(path+8, "/");
- if (!p1)
- return NULL;
- return p1+1;
+ users_lock();
+ if (users_count == 0 && need_reload)
+ do_reload();
+ users_count++;
+ users_unlock();
}
-static bool is_child_cgroup(const char *contr, const char *dir, const char *f)
+static void down_users(void)
{
- nih_local char **list = NULL;
- int i;
+ users_lock();
+ users_count--;
+ users_unlock();
+}
- if (!f)
- return false;
- if (*f == '/')
- f++;
+static void reload_handler(int sig)
+{
+ need_reload = 1;
+}
- if (!cgm_list_children(contr, dir, &list))
- return false;
- for (i = 0; list[i]; i++) {
- if (strcmp(list[i], f) == 0)
- return true;
+/* Functions to run the library methods */
+static int do_cg_getattr(const char *path, struct stat *sb)
+{
+ int (*cg_getattr)(const char *path, struct stat *sb);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_getattr = (int (*)(const char *, struct stat *)) dlsym(dlopen_handle, "cg_getattr");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
- return false;
+ return cg_getattr(path, sb);
}
-static struct cgm_keys *get_cgroup_key(const char *contr, const char *dir, const char *f)
+static int do_proc_getattr(const char *path, struct stat *sb)
{
- nih_local struct cgm_keys **list = NULL;
- struct cgm_keys *k;
- int i;
-
- if (!f)
- return NULL;
- if (*f == '/')
- f++;
- if (!cgm_list_keys(contr, dir, &list))
- return NULL;
- for (i = 0; list[i]; i++) {
- if (strcmp(list[i]->name, f) == 0) {
- k = NIH_MUST( nih_alloc(NULL, (sizeof(*k))) );
- k->name = NIH_MUST( nih_strdup(k, list[i]->name) );
- k->uid = list[i]->uid;
- k->gid = list[i]->gid;
- k->mode = list[i]->mode;
- return k;
- }
+ int (*proc_getattr)(const char *path, struct stat *sb);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ proc_getattr = (int (*)(const char *, struct stat *)) dlsym(dlopen_handle, "proc_getattr");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
- return NULL;
+ return proc_getattr(path, sb);
}
-static void get_cgdir_and_path(const char *cg, char **dir, char **file)
+static int do_cg_read(const char *path, char *buf, size_t size, off_t offset,
+ struct fuse_file_info *fi)
{
-#if 0
- nih_local char *cgcopy = NULL;
- nih_local struct cgm_keys *k = NULL;
- char *cgdir, *fpath = strrchr(cgroup, '/');
- cgcopy = NIH_MUST( nih_strdup(NULL, cgroup) );
- cgdir = dirname(cgcopy);
-#endif
- char *p;
-
- *dir = NIH_MUST( nih_strdup(NULL, cg) );
- *file = strrchr(cg, '/');
- if (!*file) {
- *file = NULL;
- return;
+ int (*cg_read)(const char *path, char *buf, size_t size, off_t offset,
+ struct fuse_file_info *fi);
+ char *error;
+
+ dlerror(); /* Clear any existing error */
+ cg_read = (int (*)(const char *, char *, size_t, off_t, struct fuse_file_info *)) dlsym(dlopen_handle, "cg_read");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
- p = strrchr(*dir, '/');
- *p = '\0';
+
+ return cg_read(path, buf, size, offset, fi);
}
-/*
- * gettattr fn for anything under /cgroup
- */
-static int cg_getattr(const char *path, struct stat *sb)
+static int do_proc_read(const char *path, char *buf, size_t size, off_t offset,
+ struct fuse_file_info *fi)
{
- struct timespec now;
- struct fuse_context *fc = fuse_get_context();
- nih_local char * cgdir = NULL;
- char *fpath = NULL, *path1, *path2;
- nih_local struct cgm_keys *k = NULL;
- const char *cgroup;
- nih_local char *controller = NULL;
-
-
- if (!fc)
- return -EIO;
-
- memset(sb, 0, sizeof(struct stat));
-
- if (clock_gettime(CLOCK_REALTIME, &now) < 0)
- return -EINVAL;
-
- sb->st_uid = sb->st_gid = 0;
- sb->st_atim = sb->st_mtim = sb->st_ctim = now;
- sb->st_size = 0;
-
- if (strcmp(path, "/cgroup") == 0) {
- sb->st_mode = S_IFDIR | 00755;
- sb->st_nlink = 2;
- return 0;
- }
-
- controller = pick_controller_from_path(fc, path);
- if (!controller)
- return -EIO;
- fprintf(stderr, "XXX getattr controller %s\n", controller);
- cgroup = find_cgroup_in_path(path);
- if (!cgroup) {
- /* this is just /cgroup/controller, return it as a dir */
- sb->st_mode = S_IFDIR | 00755;
- sb->st_nlink = 2;
- return 0;
+ int (*proc_read)(const char *path, char *buf, size_t size, off_t offset,
+ struct fuse_file_info *fi);
+ char *error;
+
+ dlerror(); /* Clear any existing error */
+ proc_read = (int (*)(const char *, char *, size_t, off_t, struct fuse_file_info *)) dlsym(dlopen_handle, "proc_read");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
-
- fprintf(stderr, "XXX getattr controller %s cgroup %s\n", controller, cgroup);
- get_cgdir_and_path(cgroup, &cgdir, &fpath);
+ return proc_read(path, buf, size, offset, fi);
+}
- if (!fpath) {
- path1 = "/";
- path2 = cgdir;
- } else {
- path1 = cgdir;
- path2 = fpath;
+static int do_cg_write(const char *path, const char *buf, size_t size, off_t offset,
+ struct fuse_file_info *fi)
+{
+ int (*cg_write)(const char *path, const char *buf, size_t size, off_t offset,
+ struct fuse_file_info *fi);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_write = (int (*)(const char *, const char *, size_t, off_t, struct fuse_file_info *)) dlsym(dlopen_handle, "cg_write");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
- fprintf(stderr, "XXX gettattr: dir is %s, basename %s\n", path1, path2);
+ return cg_write(path, buf, size, offset, fi);
+}
- /* check that cgcopy is either a child cgroup of cgdir, or listed in its keys.
- * Then check that caller's cgroup is under path if fpath is a child
- * cgroup, or cgdir if fpath is a file */
+static int do_cg_mkdir(const char *path, mode_t mode)
+{
+ int (*cg_mkdir)(const char *path, mode_t mode);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_mkdir = (int (*)(const char *, mode_t)) dlsym(dlopen_handle, "cg_mkdir");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
+ }
- if (is_child_cgroup(controller, path1, path2)) {
- if (!fc_may_access(fc, controller, cgroup, NULL, O_RDONLY))
- return -EPERM;
+ return cg_mkdir(path, mode);
+}
- sb->st_mode = S_IFDIR | 00755; // TODO what to use?
- // TODO - how to get uid, gid
- sb->st_uid = sb->st_gid = 0;
- sb->st_nlink = 2;
- return 0;
+static int do_cg_chown(const char *path, uid_t uid, gid_t gid)
+{
+ int (*cg_chown)(const char *path, uid_t uid, gid_t gid);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_chown = (int (*)(const char *, uid_t, gid_t)) dlsym(dlopen_handle, "cg_chown");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
- if ((k = get_cgroup_key(controller, path1, path2)) != NULL) {
- if (!fc_may_access(fc, controller, path1, path2, O_RDONLY))
- return -EPERM;
-
- fprintf(stderr, "XXX getattr mode on %s %s %s is %d\n", controller, path1, path2, k->mode);
+ return cg_chown(path, uid, gid);
+}
- // TODO - convert uid, gid
- sb->st_mode = S_IFREG | k->mode;
- sb->st_uid = k->uid;
- sb->st_gid = k->gid;
- sb->st_nlink = 1;
- return 0;
+static int do_cg_rmdir(const char *path)
+{
+ int (*cg_rmdir)(const char *path);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_rmdir = (int (*)(const char *path)) dlsym(dlopen_handle, "cg_rmdir");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
- return -EINVAL;
+ return cg_rmdir(path);
}
-static int cg_opendir(const char *path, struct fuse_file_info *fi)
+static int do_cg_chmod(const char *path, mode_t mode)
{
- return 0;
+ int (*cg_chmod)(const char *path, mode_t mode);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_chmod = (int (*)(const char *, mode_t)) dlsym(dlopen_handle, "cg_chmod");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
+ }
+
+ return cg_chmod(path, mode);
}
-/*
- * readdir function for anything under /cgroup
- */
-static int cg_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset,
+static int do_cg_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset,
struct fuse_file_info *fi)
{
- struct fuse_context *fc = fuse_get_context();
-
- if (!fc)
- return -EIO;
+ int (*cg_readdir)(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset,
+ struct fuse_file_info *fi);
+ char *error;
+
+ dlerror(); /* Clear any existing error */
+ cg_readdir = (int (*)(const char *, void *, fuse_fill_dir_t, off_t, struct fuse_file_info *)) dlsym(dlopen_handle, "cg_readdir");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
+ }
- if (strcmp(path, "/cgroup") == 0) {
- // get list of controllers
- char **list = LXCFS_DATA ? LXCFS_DATA->subsystems : NULL;
- int i;
+ return cg_readdir(path, buf, filler, offset, fi);
+}
- if (!list)
- return -EIO;
- /* TODO - collect the list of controllers at fuse_init */
- for (i = 0; list[i]; i++) {
- if (filler(buf, list[i], NULL, 0) != 0) {
- return -EIO;
- }
- }
- return 0;
+static int do_proc_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset,
+ struct fuse_file_info *fi)
+{
+ int (*proc_readdir)(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset,
+ struct fuse_file_info *fi);
+ char *error;
+
+ dlerror(); /* Clear any existing error */
+ proc_readdir = (int (*)(const char *, void *, fuse_fill_dir_t, off_t, struct fuse_file_info *)) dlsym(dlopen_handle, "proc_readdir");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
- // return list of keys for the controller, and list of child cgroups
- nih_local struct cgm_keys **list = NULL;
- const char *cgroup;
- nih_local char *controller = NULL;
- int i;
-
- controller = pick_controller_from_path(fc, path);
- if (!controller)
- return -EIO;
+ return proc_readdir(path, buf, filler, offset, fi);
+}
- cgroup = find_cgroup_in_path(path);
- if (!cgroup) {
- /* this is just /cgroup/controller, return its contents */
- cgroup = "/";
+static int do_cg_open(const char *path, struct fuse_file_info *fi)
+{
+ int (*cg_open)(const char *path, struct fuse_file_info *fi);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_open = (int (*)(const char *, struct fuse_file_info *)) dlsym(dlopen_handle, "cg_open");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
- if (!fc_may_access(fc, controller, cgroup, NULL, O_RDONLY))
- return -EPERM;
+ return cg_open(path, fi);
+}
- if (!cgm_list_keys(controller, cgroup, &list))
- return -EINVAL;
- for (i = 0; list[i]; i++) {
- fprintf(stderr, "adding key %s\n", list[i]->name);
- if (filler(buf, list[i]->name, NULL, 0) != 0) {
- return -EIO;
- }
+static int do_cg_access(const char *path, int mode)
+{
+ int (*cg_access)(const char *path, int mode);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_access = (int (*)(const char *, int mode)) dlsym(dlopen_handle, "cg_access");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
- // now get the list of child cgroups
- nih_local char **clist;
+ return cg_access(path, mode);
+}
- if (!cgm_list_children(controller, cgroup, &clist))
- return 0;
- for (i = 0; clist[i]; i++) {
- fprintf(stderr, "adding child %s\n", clist[i]);
- if (filler(buf, clist[i], NULL, 0) != 0) {
- return -EIO;
- }
+static int do_proc_open(const char *path, struct fuse_file_info *fi)
+{
+ int (*proc_open)(const char *path, struct fuse_file_info *fi);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ proc_open = (int (*)(const char *path, struct fuse_file_info *fi)) dlsym(dlopen_handle, "proc_open");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
}
- return 0;
+
+ return proc_open(path, fi);
}
-static int cg_releasedir(const char *path, struct fuse_file_info *fi)
+static int do_proc_access(const char *path, int mode)
{
- return 0;
+ int (*proc_access)(const char *path, int mode);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ proc_access = (int (*)(const char *, int mode)) dlsym(dlopen_handle, "proc_access");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
+ }
+
+ return proc_access(path, mode);
}
-/*
- * So far I'm not actually using cg_ops and proc_ops, but listing them
- * here makes it clearer who is supporting what. Still I prefer to
- * call the real functions and not cg_ops->getattr.
- */
-const struct fuse_operations cg_ops = {
- .getattr = cg_getattr,
- .readlink = NULL,
- .getdir = NULL,
- .mknod = NULL,
- .mkdir = NULL,
- .unlink = NULL,
- .rmdir = NULL,
- .symlink = NULL,
- .rename = NULL,
- .link = NULL,
- .chmod = NULL,
- .chown = NULL,
- .truncate = NULL,
- .utime = NULL,
- .open = NULL,
- .read = NULL,
- .write = NULL,
- .statfs = NULL,
- .flush = NULL,
- .release = NULL,
- .fsync = NULL,
+static int do_cg_release(const char *path, struct fuse_file_info *fi)
+{
+ int (*cg_release)(const char *path, struct fuse_file_info *fi);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_release = (int (*)(const char *path, struct fuse_file_info *)) dlsym(dlopen_handle, "cg_release");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
+ }
- .setxattr = NULL,
- .getxattr = NULL,
- .listxattr = NULL,
- .removexattr = NULL,
+ return cg_release(path, fi);
+}
- .opendir = cg_opendir,
- .readdir = cg_readdir,
- .releasedir = cg_releasedir,
+static int do_proc_release(const char *path, struct fuse_file_info *fi)
+{
+ int (*proc_release)(const char *path, struct fuse_file_info *fi);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ proc_release = (int (*)(const char *path, struct fuse_file_info *)) dlsym(dlopen_handle, "proc_release");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
+ }
- .fsyncdir = NULL,
- .init = NULL,
- .destroy = NULL,
- .access = NULL,
- .create = NULL,
- .ftruncate = NULL,
- .fgetattr = NULL,
-};
+ return proc_release(path, fi);
+}
-static int proc_getattr(const char *path, struct stat *sb)
+static int do_cg_opendir(const char *path, struct fuse_file_info *fi)
{
- if (strcmp(path, "/proc") != 0)
- return -EINVAL;
- sb->st_mode = S_IFDIR | 00755;
- sb->st_nlink = 2;
- return 0;
-}
+ int (*cg_opendir)(const char *path, struct fuse_file_info *fi);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_opendir = (int (*)(const char *path, struct fuse_file_info *fi)) dlsym(dlopen_handle, "cg_opendir");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
+ }
-const struct fuse_operations proc_ops = {
- .getattr = proc_getattr,
- .readlink = NULL,
- .getdir = NULL,
- .mknod = NULL,
- .mkdir = NULL,
- .unlink = NULL,
- .rmdir = NULL,
- .symlink = NULL,
- .rename = NULL,
- .link = NULL,
- .chmod = NULL,
- .chown = NULL,
- .truncate = NULL,
- .utime = NULL,
- .open = NULL,
- .read = NULL,
- .write = NULL,
- .statfs = NULL,
- .flush = NULL,
- .release = NULL,
- .fsync = NULL,
+ return cg_opendir(path, fi);
+}
- .setxattr = NULL,
- .getxattr = NULL,
- .listxattr = NULL,
- .removexattr = NULL,
+static int do_cg_releasedir(const char *path, struct fuse_file_info *fi)
+{
+ int (*cg_releasedir)(const char *path, struct fuse_file_info *fi);
+ char *error;
+ dlerror(); /* Clear any existing error */
+ cg_releasedir = (int (*)(const char *path, struct fuse_file_info *)) dlsym(dlopen_handle, "cg_releasedir");
+ error = dlerror();
+ if (error != NULL) {
+ lxcfs_error("%s\n", error);
+ return -1;
+ }
- .opendir = NULL,
- .readdir = NULL,
- .releasedir = NULL,
+ return cg_releasedir(path, fi);
+}
- .fsyncdir = NULL,
- .init = NULL,
- .destroy = NULL,
- .access = NULL,
- .create = NULL,
- .ftruncate = NULL,
- .fgetattr = NULL,
-};
+/*
+ * FUSE ops for /
+ * these just delegate to the /proc and /cgroup ops as
+ * needed
+ */
static int lxcfs_getattr(const char *path, struct stat *sb)
{
+ int ret;
+ struct timespec now;
+
if (strcmp(path, "/") == 0) {
+ if (clock_gettime(CLOCK_REALTIME, &now) < 0)
+ return -EINVAL;
+ sb->st_uid = sb->st_gid = 0;
+ sb->st_atim = sb->st_mtim = sb->st_ctim = now;
+ sb->st_size = 0;
sb->st_mode = S_IFDIR | 00755;
sb->st_nlink = 2;
return 0;
}
+
if (strncmp(path, "/cgroup", 7) == 0) {
- return cg_getattr(path, sb);
+ up_users();
+ ret = do_cg_getattr(path, sb);
+ down_users();
+ return ret;
}
- if (strncmp(path, "/proc", 7) == 0) {
- return proc_getattr(path, sb);
+ if (strncmp(path, "/proc", 5) == 0) {
+ up_users();
+ ret = do_proc_getattr(path, sb);
+ down_users();
+ return ret;
}
- return -EINVAL;
+ return -ENOENT;
}
static int lxcfs_opendir(const char *path, struct fuse_file_info *fi)
{
+ int ret;
if (strcmp(path, "/") == 0)
return 0;
if (strncmp(path, "/cgroup", 7) == 0) {
- return cg_opendir(path, fi);
+ up_users();
+ ret = do_cg_opendir(path, fi);
+ down_users();
+ return ret;
}
- return -EINVAL;
+ if (strcmp(path, "/proc") == 0)
+ return 0;
+ return -ENOENT;
}
static int lxcfs_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset,
struct fuse_file_info *fi)
{
+ int ret;
if (strcmp(path, "/") == 0) {
- if (filler(buf, "proc", NULL, 0) != 0 ||
- filler(buf, "cgroup", NULL, 0) != 0)
- return -EINVAL;
+ if (filler(buf, ".", NULL, 0) != 0 ||
+ filler(buf, "..", NULL, 0) != 0 ||
+ filler(buf, "proc", NULL, 0) != 0 ||
+ filler(buf, "cgroup", NULL, 0) != 0)
+ return -ENOMEM;
return 0;
}
if (strncmp(path, "/cgroup", 7) == 0) {
- return cg_readdir(path, buf, filler, offset, fi);
+ up_users();
+ ret = do_cg_readdir(path, buf, filler, offset, fi);
+ down_users();
+ return ret;
}
- return -EINVAL;
+ if (strcmp(path, "/proc") == 0) {
+ up_users();
+ ret = do_proc_readdir(path, buf, filler, offset, fi);
+ down_users();
+ return ret;
+ }
+ return -ENOENT;
+}
+
+static int lxcfs_access(const char *path, int mode)
+{
+ int ret;
+
+ if (strcmp(path, "/") == 0 && (mode & W_OK) == 0)
+ return 0;
+
+ if (strncmp(path, "/cgroup", 7) == 0) {
+ up_users();
+ ret = do_cg_access(path, mode);
+ down_users();
+ return ret;
+ }
+ if (strncmp(path, "/proc", 5) == 0) {
+ up_users();
+ ret = do_proc_access(path, mode);
+ down_users();
+ return ret;
+ }
+
+ return -EACCES;
}
static int lxcfs_releasedir(const char *path, struct fuse_file_info *fi)
{
+ int ret;
if (strcmp(path, "/") == 0)
return 0;
if (strncmp(path, "/cgroup", 7) == 0) {
- return cg_releasedir(path, fi);
+ up_users();
+ ret = do_cg_releasedir(path, fi);
+ down_users();
+ return ret;
+ }
+ if (strcmp(path, "/proc") == 0)
+ return 0;
+ return -EINVAL;
+}
+
+static int lxcfs_open(const char *path, struct fuse_file_info *fi)
+{
+ int ret;
+ if (strncmp(path, "/cgroup", 7) == 0) {
+ up_users();
+ ret = do_cg_open(path, fi);
+ down_users();
+ return ret;
+ }
+ if (strncmp(path, "/proc", 5) == 0) {
+ up_users();
+ ret = do_proc_open(path, fi);
+ down_users();
+ return ret;
+ }
+
+ return -EACCES;
+}
+
+static int lxcfs_read(const char *path, char *buf, size_t size, off_t offset,
+ struct fuse_file_info *fi)
+{
+ int ret;
+ if (strncmp(path, "/cgroup", 7) == 0) {
+ up_users();
+ ret = do_cg_read(path, buf, size, offset, fi);
+ down_users();
+ return ret;
+ }
+ if (strncmp(path, "/proc", 5) == 0) {
+ up_users();
+ ret = do_proc_read(path, buf, size, offset, fi);
+ down_users();
+ return ret;
+ }
+
+ return -EINVAL;
+}
+
+int lxcfs_write(const char *path, const char *buf, size_t size, off_t offset,
+ struct fuse_file_info *fi)
+{
+ int ret;
+ if (strncmp(path, "/cgroup", 7) == 0) {
+ up_users();
+ ret = do_cg_write(path, buf, size, offset, fi);
+ down_users();
+ return ret;
+ }
+
+ return -EINVAL;
+}
+
+static int lxcfs_flush(const char *path, struct fuse_file_info *fi)
+{
+ return 0;
+}
+
+static int lxcfs_release(const char *path, struct fuse_file_info *fi)
+{
+ int ret;
+ if (strncmp(path, "/cgroup", 7) == 0) {
+ up_users();
+ ret = do_cg_release(path, fi);
+ down_users();
+ return ret;
}
+ if (strncmp(path, "/proc", 5) == 0) {
+ up_users();
+ ret = do_proc_release(path, fi);
+ down_users();
+ return ret;
+ }
+
return -EINVAL;
}
-void *bb_init(struct fuse_conn_info *conn)
+static int lxcfs_fsync(const char *path, int datasync, struct fuse_file_info *fi)
+{
+ return 0;
+}
+
+int lxcfs_mkdir(const char *path, mode_t mode)
+{
+ int ret;
+ if (strncmp(path, "/cgroup", 7) == 0) {
+ up_users();
+ ret = do_cg_mkdir(path, mode);
+ down_users();
+ return ret;
+ }
+
+ return -EPERM;
+}
+
+int lxcfs_chown(const char *path, uid_t uid, gid_t gid)
+{
+ int ret;
+ if (strncmp(path, "/cgroup", 7) == 0) {
+ up_users();
+ ret = do_cg_chown(path, uid, gid);
+ down_users();
+ return ret;
+ }
+
+ if (strncmp(path, "/proc", 5) == 0)
+ return -EPERM;
+
+ return -ENOENT;
+}
+
+/*
+ * cat first does a truncate before doing ops->write. This doesn't
+ * really make sense for cgroups. So just return 0 always but do
+ * nothing.
+ */
+int lxcfs_truncate(const char *path, off_t newsize)
{
- return LXCFS_DATA;
+ if (strncmp(path, "/cgroup", 7) == 0)
+ return 0;
+ return -EPERM;
+}
+
+int lxcfs_rmdir(const char *path)
+{
+ int ret;
+ if (strncmp(path, "/cgroup", 7) == 0) {
+ up_users();
+ ret = do_cg_rmdir(path);
+ down_users();
+ return ret;
+ }
+ return -EPERM;
+}
+
+int lxcfs_chmod(const char *path, mode_t mode)
+{
+ int ret;
+ if (strncmp(path, "/cgroup", 7) == 0) {
+ up_users();
+ ret = do_cg_chmod(path, mode);
+ down_users();
+ return ret;
+ }
+
+ if (strncmp(path, "/proc", 5) == 0)
+ return -EPERM;
+
+ return -ENOENT;
}
const struct fuse_operations lxcfs_ops = {
.readlink = NULL,
.getdir = NULL,
.mknod = NULL,
- .mkdir = NULL,
+ .mkdir = lxcfs_mkdir,
.unlink = NULL,
- .rmdir = NULL,
+ .rmdir = lxcfs_rmdir,
.symlink = NULL,
.rename = NULL,
.link = NULL,
- .chmod = NULL,
- .chown = NULL,
- .truncate = NULL,
+ .chmod = lxcfs_chmod,
+ .chown = lxcfs_chown,
+ .truncate = lxcfs_truncate,
.utime = NULL,
- .open = NULL,
- .read = NULL,
- .write = NULL,
+
+ .open = lxcfs_open,
+ .read = lxcfs_read,
+ .release = lxcfs_release,
+ .write = lxcfs_write,
+
.statfs = NULL,
- .flush = NULL,
- .release = NULL,
- .fsync = NULL,
+ .flush = lxcfs_flush,
+ .fsync = lxcfs_fsync,
.setxattr = NULL,
.getxattr = NULL,
.fsyncdir = NULL,
.init = NULL,
.destroy = NULL,
- .access = NULL,
+ .access = lxcfs_access,
.create = NULL,
.ftruncate = NULL,
.fgetattr = NULL,
};
-void usage(const char *me)
+static void usage()
{
fprintf(stderr, "Usage:\n");
fprintf(stderr, "\n");
- fprintf(stderr, "%s [FUSE and mount options] mountpoint\n", me);
+ fprintf(stderr, "lxcfs [-f|-d] [-p pidfile] mountpoint\n");
+ fprintf(stderr, " -f running foreground by default; -d enable debug output \n");
+ fprintf(stderr, " Default pidfile is %s/lxcfs.pid\n", RUNTIME_PATH);
+ fprintf(stderr, "lxcfs -h\n");
exit(1);
}
-bool is_help(char *w)
+static bool is_help(char *w)
{
if (strcmp(w, "-h") == 0 ||
strcmp(w, "--help") == 0 ||
return false;
}
-int main(int argc, char *argv[])
+bool swallow_arg(int *argcp, char *argv[], char *which)
{
- int ret;
- struct lxcfs_state *d;
+ int i;
- if (argc < 2 || is_help(argv[1]))
- usage(argv[0]);
+ for (i = 1; argv[i]; i++) {
+ if (strcmp(argv[i], which) != 0)
+ continue;
+ for (; argv[i]; i++) {
+ argv[i] = argv[i+1];
+ }
+ (*argcp)--;
+ return true;
+ }
+ return false;
+}
+
+bool swallow_option(int *argcp, char *argv[], char *opt, char **v)
+{
+ int i;
- d = malloc(sizeof(*d));
- if (!d)
+ for (i = 1; argv[i]; i++) {
+ if (!argv[i+1])
+ continue;
+ if (strcmp(argv[i], opt) != 0)
+ continue;
+ do {
+ *v = strdup(argv[i+1]);
+ } while (!*v);
+ for (; argv[i+1]; i++) {
+ argv[i] = argv[i+2];
+ }
+ (*argcp) -= 2;
+ return true;
+ }
+ return false;
+}
+
+static int set_pidfile(char *pidfile)
+{
+ int fd;
+ char buf[50];
+ struct flock fl;
+
+ fl.l_type = F_WRLCK;
+ fl.l_whence = SEEK_SET;
+ fl.l_start = 0;
+ fl.l_len = 0;
+
+ fd = open(pidfile, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
+ if (fd == -1) {
+ fprintf(stderr, "Could not open pidfile %s: %m\n", pidfile);
return -1;
+ }
- if (!cgm_escape_cgroup())
- fprintf(stderr, "WARNING: failed to escape to root cgroup\n");
+ if (fcntl(fd, F_SETLK, &fl) == -1) {
+ if (errno == EAGAIN || errno == EACCES) {
+ fprintf(stderr, "PID file '%s' is already locked.\n", pidfile);
+ close(fd);
+ return -1;
+ }
+ fprintf(stderr, "Warning; unable to lock PID file, proceeding.\n");
+ }
- if (!cgm_get_controllers(&d->subsystems))
+ if (ftruncate(fd, 0) == -1) {
+ fprintf(stderr, "Error truncating PID file '%s': %m", pidfile);
+ close(fd);
return -1;
+ }
+
+ snprintf(buf, 50, "%ld\n", (long) getpid());
+ if (write(fd, buf, strlen(buf)) != strlen(buf)) {
+ fprintf(stderr, "Error writing to PID file '%s': %m", pidfile);
+ close(fd);
+ return -1;
+ }
+
+ return fd;
+}
- ret = fuse_main(argc, argv, &lxcfs_ops, d);
+int main(int argc, char *argv[])
+{
+ int ret = EXIT_FAILURE;
+ int pidfd = -1;
+ char *pidfile = NULL, *v = NULL;
+ size_t pidfile_len;
+ bool debug = false;
+ /*
+ * what we pass to fuse_main is:
+ * argv[0] -s [-f|-d] -o allow_other,directio argv[1] NULL
+ */
+ int nargs = 5, cnt = 0;
+ char *newargv[6];
+
+ /* accomodate older init scripts */
+ swallow_arg(&argc, argv, "-s");
+ swallow_arg(&argc, argv, "-f");
+ debug = swallow_arg(&argc, argv, "-d");
+ if (swallow_option(&argc, argv, "-o", &v)) {
+ if (strcmp(v, "allow_other") != 0) {
+ fprintf(stderr, "Warning: unexpected fuse option %s\n", v);
+ exit(EXIT_FAILURE);
+ }
+ free(v);
+ v = NULL;
+ }
+ if (swallow_option(&argc, argv, "-p", &v))
+ pidfile = v;
- return ret;
+ if (argc == 2 && strcmp(argv[1], "--version") == 0) {
+ fprintf(stderr, "%s\n", VERSION);
+ exit(EXIT_SUCCESS);
+ }
+ if (argc != 2 || is_help(argv[1]))
+ usage();
+
+ do_reload();
+ if (signal(SIGUSR1, reload_handler) == SIG_ERR) {
+ fprintf(stderr, "Error setting USR1 signal handler: %m\n");
+ goto out;
+ }
+
+ newargv[cnt++] = argv[0];
+ if (debug) {
+ newargv[cnt++] = "-d";
+ } else {
+ newargv[cnt++] = "-f";
+ }
+ newargv[cnt++] = "-o";
+ newargv[cnt++] = "allow_other,direct_io,entry_timeout=0.5,attr_timeout=0.5";
+ newargv[cnt++] = argv[1];
+ newargv[cnt++] = NULL;
+
+ if (!pidfile) {
+ pidfile_len = strlen(RUNTIME_PATH) + strlen("/lxcfs.pid") + 1;
+ pidfile = alloca(pidfile_len);
+ snprintf(pidfile, pidfile_len, "%s/lxcfs.pid", RUNTIME_PATH);
+ }
+ if ((pidfd = set_pidfile(pidfile)) < 0)
+ goto out;
+
+ if (!fuse_main(nargs, newargv, &lxcfs_ops, NULL))
+ ret = EXIT_SUCCESS;
+
+out:
+ if (dlopen_handle)
+ dlclose(dlopen_handle);
+ if (pidfile)
+ unlink(pidfile);
+ if (pidfd > 0)
+ close(pidfd);
+ exit(ret);
}
projects / mirror_lxcfs.git / blobdiff