#define FUSE_USE_VERSION 26
+#define _GNU_SOURCE
#include <fuse.h>
#include <stdlib.h>
#include <library.h>
#include <debug.h>
+/** define _XOPEN_SOURCE 500 fails when using libstrongswan, define popen */
+extern ssize_t pread(int fd, void *buf, size_t count, off_t offset);
+extern ssize_t pwrite(int fd, const void *buf, size_t count, off_t offset);
+
typedef struct private_cowfs_t private_cowfs_t;
struct private_cowfs_t {
struct fuse *fuse;
/** mountpoint of cowfs FUSE */
char *mount;
- /** read only master filesystem */
+ /** master filesystem path */
char *master;
- /** copy on write overlay to master */
+ /** host filesystem path */
char *host;
+ /** scenario filesystem path */
+ char *scen;
+ /** fd of read only master filesystem */
+ int master_fd;
+ /** copy on write overlay to master */
+ int host_fd;
/** optional scenario COW overlay */
- char *scenario;
+ int scen_fd;
/** thread processing FUSE */
pthread_t thread;
};
+static private_cowfs_t *get_this()
+{
+ return (fuse_get_context())->private_data;
+}
-static int cowfs_getattr(const char *path, struct stat *stbuf)
+static void rel(const char **path)
{
- int res;
+ if (**path == '/')
+ {
+ (*path)++;
+ }
+ if (**path == '\0')
+ {
+ *path = ".";
+ }
+}
- res = lstat(path, stbuf);
- if (res == -1)
- return -errno;
+/**
+ * get the filesystem to read something from
+ */
+static int get_rd(const char *path)
+{
+ private_cowfs_t *this = get_this();
- return 0;
+ if (this->scen_fd > 0 && faccessat(this->scen_fd, path, F_OK, 0) == 0)
+ {
+ return this->scen_fd;
+ }
+ if (faccessat(this->host_fd, path, F_OK, 0) == 0)
+ {
+ return this->host_fd;
+ }
+ return this->master_fd;
}
-static int cowfs_access(const char *path, int mask)
+/**
+ * get the filesystem to write something to
+ */
+static int get_wr(const char *path)
{
- int res;
+ private_cowfs_t *this = get_this();
+ if (this->scen_fd > 0)
+ {
+ return this->scen_fd;
+ }
+ return this->host_fd;
+}
- res = access(path, mask);
- if (res == -1)
- return -errno;
+/**
+ * create all directories need to create the file "path"
+ */
+static bool clone_path(int rd, int wr, const char *path)
+{
+ char *pos, *full;
+ struct stat st;
+ full = strdupa(path);
+ pos = full;
+
+ while ((pos = strchr(pos, '/')))
+ {
+ *pos = '\0';
+ if (fstatat(wr, full, &st, 0) < 0)
+ {
+ /* TODO: handle symlinks! */
+ if (fstatat(rd, full, &st, 0) < 0)
+ {
+ return FALSE;
+ }
+ if (mkdirat(wr, full, st.st_mode) < 0)
+ {
+ return FALSE;
+ }
+ }
+ *pos = '/';
+ pos++;
+ }
+ return TRUE;
+}
+
+/**
+ * copy a file from a readonly to a read-write overlay
+ */
+static int copy(const char *path)
+{
+ char *buf[4096];
+ int len;
+ int rd, wr;
+ int from, to;
+ struct stat st;
+
+ rd = get_rd(path);
+ wr = get_wr(path);
+
+ if (rd == wr)
+ {
+ /* already writeable */
+ return wr;
+ }
+ if (fstatat(rd, path, &st, 0) < 0)
+ {
+ return -1;
+ }
+ from = openat(rd, path, O_RDONLY, st.st_mode);
+ if (from < 0)
+ {
+ return -1;
+ }
+ if (!clone_path(rd, wr, path))
+ {
+ return -1;
+ }
+ to = openat(wr, path, O_WRONLY | O_CREAT, st.st_mode);
+ if (to < 0)
+ {
+ close(from);
+ return -1;
+ }
+ while ((len = read(from, buf, sizeof(buf))) > 0)
+ {
+ if (write(to, buf, len) < len)
+ {
+ close(from);
+ close(to);
+ return -1;
+ }
+ }
+ close(from);
+ close(to);
+ if (len < 0)
+ {
+ return -1;
+ }
+ return wr;
+}
+
+/**
+ * FUSE getattr method
+ */
+static int cowfs_getattr(const char *path, struct stat *stbuf)
+{
+ rel(&path);
+
+ if (fstatat(get_rd(path), path, stbuf, AT_SYMLINK_NOFOLLOW) < 0)
+ {
+ return -errno;
+ }
+ return 0;
+}
+/**
+ * FUSE access method
+ */
+static int cowfs_access(const char *path, int mask)
+{
+ rel(&path);
+
+ if (faccessat(get_rd(path), path, mask, 0) < 0)
+ {
+ return -errno;
+ }
return 0;
}
+/**
+ * FUSE readlink method
+ */
static int cowfs_readlink(const char *path, char *buf, size_t size)
{
- int res;
+ int res;
- res = readlink(path, buf, size - 1);
- if (res == -1)
+ rel(&path);
+
+ res = readlinkat(get_rd(path), path, buf, size - 1);
+ if (res < 0)
+ {
return -errno;
-
+ }
buf[res] = '\0';
return 0;
}
-
-static int cowfs_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
- off_t offset, struct fuse_file_info *fi)
+/**
+ * get a directory stream of two concatenated paths
+ */
+static DIR* get_dir(char *dir, const char *subdir)
{
- DIR *dp;
- struct dirent *de;
-
- (void) offset;
- (void) fi;
-
- dp = opendir(path);
- if (dp == NULL)
- return -errno;
+ char *full;
+
+ if (dir == NULL)
+ {
+ return NULL;
+ }
+
+ full = alloca(strlen(dir) + strlen(subdir) + 1);
+ strcpy(full, dir);
+ strcat(full, subdir);
+
+ return opendir(full);
+}
- while ((de = readdir(dp)) != NULL) {
- struct stat st;
- memset(&st, 0, sizeof(st));
- st.st_ino = de->d_ino;
- st.st_mode = de->d_type << 12;
- if (filler(buf, de->d_name, &st, 0))
- break;
- }
+/**
+ * check if a directory stream contains a directory
+ */
+static bool contains_dir(DIR *d, char *dirname)
+{
+ if (d)
+ {
+ struct dirent *ent;
+
+ rewinddir(d);
+ while ((ent = readdir(d)))
+ {
+ if (streq(ent->d_name, dirname))
+ {
+ return TRUE;
+ }
+ }
+ }
+ return FALSE;
+}
- closedir(dp);
+/**
+ * FUSE readdir method
+ */
+static int cowfs_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
+ off_t offset, struct fuse_file_info *fi)
+{
+ private_cowfs_t *this = get_this();
+ DIR *d1, *d2, *d3;
+ struct stat st;
+ struct dirent *ent;
+
+ memset(&st, 0, sizeof(st));
+
+ d1 = get_dir(this->master, path);
+ d2 = get_dir(this->host, path);
+ d3 = get_dir(this->scen, path);
+
+ if (d1)
+ {
+ while ((ent = readdir(d1)))
+ {
+ if (!contains_dir(d2, ent->d_name) &&
+ !contains_dir(d3, ent->d_name))
+ {
+ st.st_ino = ent->d_ino;
+ st.st_mode = ent->d_type << 12;
+ filler(buf, ent->d_name, &st, 0);
+ }
+ }
+ closedir(d1);
+ }
+ if (d2)
+ {
+ rewinddir(d2);
+ while ((ent = readdir(d2)))
+ {
+ if (!contains_dir(d3, ent->d_name))
+ {
+ st.st_ino = ent->d_ino;
+ st.st_mode = ent->d_type << 12;
+ filler(buf, ent->d_name, &st, 0);
+ }
+ }
+ closedir(d2);
+ }
+ if (d3)
+ {
+ rewinddir(d3);
+ while ((ent = readdir(d3)))
+ {
+ st.st_ino = ent->d_ino;
+ st.st_mode = ent->d_type << 12;
+ filler(buf, ent->d_name, &st, 0);
+ }
+ closedir(d3);
+ }
return 0;
}
+/**
+ * FUSE mknod method
+ */
static int cowfs_mknod(const char *path, mode_t mode, dev_t rdev)
{
- int res;
+ int fd;
+ rel(&path);
- res = mknod(path, mode, rdev);
- if (res == -1)
- return -errno;
+ fd = get_wr(path);
+ if (!clone_path(get_rd(path), fd, path))
+ {
+ return -errno;
+ }
- return 0;
+ if (mknodat(fd, path, mode, rdev) < 0)
+ {
+ return -errno;
+ }
+ return 0;
}
+/**
+ * FUSE mkdir method
+ */
static int cowfs_mkdir(const char *path, mode_t mode)
{
- int res;
+ int fd;
+ rel(&path);
- res = mkdir(path, mode);
- if (res == -1)
- return -errno;
-
- return 0;
+ fd = get_wr(path);
+ if (!clone_path(get_rd(path), fd, path))
+ {
+ return -errno;
+ }
+ if (mkdirat(fd, path, mode) < 0)
+ {
+ return -errno;
+ }
+ return 0;
}
+/**
+ * FUSE unlink method
+ */
static int cowfs_unlink(const char *path)
{
- int res;
-
- res = unlink(path);
- if (res == -1)
- return -errno;
-
+ rel(&path);
+
+ /* TODO: whiteout master */
+ if (unlinkat(get_wr(path), path, 0) < 0)
+ {
+ return -errno;
+ }
return 0;
}
+/**
+ * FUSE rmdir method
+ */
static int cowfs_rmdir(const char *path)
{
- int res;
-
- res = rmdir(path);
- if (res == -1)
- return -errno;
-
+ rel(&path);
+
+ /* TODO: whiteout master */
+ if (unlinkat(get_wr(path), path, AT_REMOVEDIR) < 0)
+ {
+ return -errno;
+ }
return 0;
}
+/**
+ * FUSE symlink method
+ */
static int cowfs_symlink(const char *from, const char *to)
{
- int res;
-
- res = symlink(from, to);
- if (res == -1)
- return -errno;
+ rel(&to);
- return 0;
+ /* TODO: relative from? */
+ if (symlinkat(from, get_wr(to), to) < 0)
+ {
+ return -errno;
+ }
+ return 0;
}
+/**
+ * FUSE rename method
+ */
static int cowfs_rename(const char *from, const char *to)
{
- int res;
+ int fd;
+ private_cowfs_t *this = get_this();
- res = rename(from, to);
- if (res == -1)
- return -errno;
+ rel(&from);
+ rel(&to);
- return 0;
+ fd = get_rd(from);
+ if (fd == this->master_fd)
+ {
+ fd = copy(from);
+ if (fd < 0)
+ {
+ return -errno;
+ }
+ }
+
+ if (renameat(fd, from, get_wr(to), to) < 0)
+ {
+ return -errno;
+ }
+ return 0;
}
+/**
+ * FUSE link method
+ */
static int cowfs_link(const char *from, const char *to)
{
- int res;
-
- res = link(from, to);
- if (res == -1)
- return -errno;
+ rel(&from);
+ rel(&to);
+ if (linkat(get_rd(from), from, get_wr(to), to, 0) < 0)
+ {
+ return -errno;
+ }
return 0;
}
+/**
+ * FUSE chmod method
+ */
static int cowfs_chmod(const char *path, mode_t mode)
{
- int res;
-
- res = chmod(path, mode);
- if (res == -1)
- return -errno;
-
- return 0;
+ int fd;
+ struct stat st;
+ private_cowfs_t *this = get_this();
+
+ rel(&path);
+ fd = get_rd(path);
+ if (fd == this->master_fd)
+ {
+ if (fstatat(fd, path, &st, 0) < 0)
+ {
+ return -errno;
+ }
+ if (st.st_mode == mode)
+ {
+ return 0;
+ }
+ fd = copy(path);
+ if (fd < 0)
+ {
+ return -errno;
+ }
+ }
+ if (fchmodat(fd, path, mode, 0) < 0)
+ {
+ return -errno;
+ }
+ return 0;
}
+/**
+ * FUSE chown method
+ */
static int cowfs_chown(const char *path, uid_t uid, gid_t gid)
{
- int res;
-
- res = lchown(path, uid, gid);
- if (res == -1)
- return -errno;
-
- return 0;
+ int fd;
+ struct stat st;
+ private_cowfs_t *this = get_this();
+
+ rel(&path);
+ fd = get_rd(path);
+ if (fd == this->master_fd)
+ {
+ if (fstatat(fd, path, &st, 0) < 0)
+ {
+ return -errno;
+ }
+ if (st.st_uid == uid && st.st_gid == gid)
+ {
+ return 0;
+ }
+ fd = copy(path);
+ if (fd < 0)
+ {
+ return -errno;
+ }
+ }
+ if (fchownat(fd, path, uid, gid, AT_SYMLINK_NOFOLLOW) < 0)
+ {
+ return -errno;
+ }
+ return 0;
}
+/**
+ * FUSE truncate method
+ */
static int cowfs_truncate(const char *path, off_t size)
{
- int res;
-
- res = truncate(path, size);
- if (res == -1)
- return -errno;
+ int fd;
+ struct stat st;
+ private_cowfs_t *this = get_this();
- return 0;
+ rel(&path);
+ fd = get_rd(path);
+ if (fd == this->master_fd)
+ {
+ if (fstatat(fd, path, &st, 0) < 0)
+ {
+ return -errno;
+ }
+ if (st.st_size == size)
+ {
+ return 0;
+ }
+ fd = copy(path);
+ if (fd < 0)
+ {
+ return -errno;
+ }
+ }
+ fd = openat(fd, path, O_WRONLY);
+ if (fd < 0)
+ {
+ return -errno;
+ }
+ if (ftruncate(fd, size) < 0)
+ {
+ close(fd);
+ return -errno;
+ }
+ close(fd);
+ return 0;
}
+/**
+ * FUSE utimens method
+ */
static int cowfs_utimens(const char *path, const struct timespec ts[2])
{
- int res;
- struct timeval tv[2];
+ struct timeval tv[2];
+ int fd;
+ private_cowfs_t *this = get_this();
- tv[0].tv_sec = ts[0].tv_sec;
- tv[0].tv_usec = ts[0].tv_nsec / 1000;
- tv[1].tv_sec = ts[1].tv_sec;
- tv[1].tv_usec = ts[1].tv_nsec / 1000;
+ rel(&path);
+ fd = get_rd(path);
+ if (fd == this->master_fd)
+ {
+ fd = copy(path);
+ if (fd < 0)
+ {
+ return -errno;
+ }
+ }
- res = utimes(path, tv);
- if (res == -1)
- return -errno;
+ tv[0].tv_sec = ts[0].tv_sec;
+ tv[0].tv_usec = ts[0].tv_nsec / 1000;
+ tv[1].tv_sec = ts[1].tv_sec;
+ tv[1].tv_usec = ts[1].tv_nsec / 1000;
- return 0;
+ if (futimesat(fd, path, tv) < 0)
+ {
+ return -errno;
+ }
+ return 0;
}
+/**
+ * FUSE open method
+ */
static int cowfs_open(const char *path, struct fuse_file_info *fi)
{
- int res;
+ int fd;
- res = open(path, fi->flags);
- if (res == -1)
- return -errno;
+ rel(&path);
+ fd = get_rd(path);
- close(res);
- return 0;
+ fd = openat(fd, path, fi->flags);
+ if (fd < 0)
+ {
+ return -errno;
+ }
+ close(fd);
+ return 0;
}
+/**
+ * FUSE read method
+ */
static int cowfs_read(const char *path, char *buf, size_t size, off_t offset,
- struct fuse_file_info *fi)
+ struct fuse_file_info *fi)
{
- int fd;
- int res;
+ int file, fd, res;
- (void) fi;
- fd = open(path, O_RDONLY);
- if (fd == -1)
- return -errno;
+ rel(&path);
- res = pread(fd, buf, size, offset);
- if (res == -1)
- res = -errno;
+ fd = get_rd(path);
- close(fd);
- return res;
+ file = openat(fd, path, O_RDONLY);
+ if (file < 0)
+ {
+ return -errno;
+ }
+ res = pread(file, buf, size, offset);
+ if (res < 0)
+ {
+ res = -errno;
+ }
+ close(file);
+ return res;
}
+/**
+ * FUSE write method
+ */
static int cowfs_write(const char *path, const char *buf, size_t size,
- off_t offset, struct fuse_file_info *fi)
+ off_t offset, struct fuse_file_info *fi)
{
- int fd;
- int res;
-
- (void) fi;
- fd = open(path, O_WRONLY);
- if (fd == -1)
- return -errno;
+ private_cowfs_t *this = get_this();
+ int file, fd, res;
- res = pwrite(fd, buf, size, offset);
- if (res == -1)
- res = -errno;
+ rel(&path);
- close(fd);
- return res;
+ fd = get_rd(path);
+ if (fd == this->master_fd)
+ {
+ fd = copy(path);
+ if (fd < 0)
+ {
+ return -errno;
+ }
+ }
+ file = openat(fd, path, O_WRONLY);
+ if (file < 0)
+ {
+ return -errno;
+ }
+ res = pwrite(file, buf, size, offset);
+ if (res < 0)
+ {
+ res = -errno;
+ }
+ close(file);
+ return res;
}
+/**
+ * FUSE statfs method
+ */
static int cowfs_statfs(const char *path, struct statvfs *stbuf)
{
- int res;
-
- res = statvfs(path, stbuf);
- if (res == -1)
- return -errno;
+ private_cowfs_t *this = get_this();
+ int fd;
+
+ fd = this->host_fd;
+ if (this->scen_fd > 0)
+ {
+ fd = this->scen_fd;
+ }
+ if (fstatvfs(fd, stbuf) < 0)
+ {
+ return -errno;
+ }
+
return 0;
}
+/**
+ * FUSE init method
+ */
static void *cowfs_init(struct fuse_conn_info *conn)
{
struct fuse_context *ctx;
return ctx->private_data;
}
+/**
+ * FUSE method vectors
+ */
static struct fuse_operations cowfs_operations = {
.getattr = cowfs_getattr,
.access = cowfs_access,
*/
static void set_scenario(private_cowfs_t *this, char *path)
{
- free(this->scenario);
- this->scenario = path ? strdup(path) : NULL;
+ if (this->scen)
+ {
+ free(this->scen);
+ }
+ if (this->scen_fd > 0)
+ {
+ close(this->scen_fd);
+ }
+ this->scen = strdup(path);
+ this->scen_fd = open(path, O_RDONLY | O_DIRECTORY);
}
/**
free(this->mount);
free(this->master);
free(this->host);
- free(this->scenario);
+ free(this->scen);
+ close(this->master_fd);
+ close(this->host_fd);
+ if (this->scen_fd > 0)
+ {
+ close(this->scen_fd);
+ }
free(this);
}
this->public.set_scenario = (void(*)(cowfs_t*, char *path))set_scenario;
this->public.destroy = (void(*)(cowfs_t*))destroy;
+ this->master_fd = open(master, O_RDONLY | O_DIRECTORY);
+ if (this->master_fd < 0)
+ {
+ DBG1("failed to open master filesystem '%s'", master);
+ free(this);
+ }
+ this->host_fd = open(host, O_RDONLY | O_DIRECTORY);
+ if (this->master_fd < 0)
+ {
+ DBG1("failed to open host filesystem '%s'", host);
+ close(this->master_fd);
+ free(this);
+ }
+ this->scen_fd = -1;
+
this->chan = fuse_mount(mount, &args);
if (this->chan == NULL)
{
DBG1("mounting cowfs FUSE on '%s' failed", mount);
+ close(this->master_fd);
+ close(this->host_fd);
free(this);
return NULL;
}
if (this->fuse == NULL)
{
DBG1("creating cowfs FUSE handle failed");
+ close(this->master_fd);
+ close(this->host_fd);
fuse_unmount(mount, this->chan);
free(this);
return NULL;
this->mount = strdup(mount);
this->master = strdup(master);
this->host = strdup(host);
- this->scenario = NULL;
+ this->scen = NULL;
if (pthread_create(&this->thread, NULL, (void*)fuse_loop_mt, this->fuse) != 0)
{
free(this->mount);
free(this->master);
free(this->host);
+ close(this->master_fd);
+ close(this->host_fd);
free(this);
return NULL;
}
projects / strongswan.git / commitdiff