/* * mount.c * * This file implements mounting of WIM files using FUSE, which stands for * Filesystem in Userspace. FUSE allows a filesystem to be implemented in a * userspace process by implementing the filesystem primitives--- read(), * write(), readdir(), etc. */ /* * Copyright (C) 2012 Eric Biggers * * This file is part of wimlib, a library for working with WIM files. * * wimlib is free software; you can redistribute it and/or modify it under the * terms of the GNU Lesser General Public License as published by the Free * Software Foundation; either version 2.1 of the License, or (at your option) * any later version. * * wimlib 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 Lesser General Public License for more * details. * * You should have received a copy of the GNU Lesser General Public License * along with wimlib; if not, see http://www.gnu.org/licenses/. */ #include "wimlib_internal.h" #ifdef WITH_FUSE #include "sha1.h" #include "lookup_table.h" #include "xml.h" #include "io.h" #include "timestamp.h" #include #include #include #define FUSE_USE_VERSION 26 #include #include #include #include #include #include struct wimlib_fd { u16 idx; int staging_fd; u64 hard_link_group; struct lookup_table_entry *lte; struct dentry *dentry; }; /* The WIMStruct for the mounted WIM. */ static WIMStruct *w; /* Working directory when `imagex mount' is run. */ static const char *working_directory; /* Name of the staging directory for a read-write mount. Whenever a new file is * created, it is done so in the staging directory. Furthermore, whenever a * file in the WIM is modified, it is extracted to the staging directory. If * changes are commited when the WIM is unmounted, the file resources are merged * in from the staging directory when writing the new WIM. */ static char *staging_dir_name; static size_t staging_dir_name_len; /* Flags passed to wimlib_mount(). */ static int mount_flags; /* Name of the directory on which the WIM file is mounted. */ static const char *mount_dir; static inline int get_lookup_flags() { if (mount_flags & WIMLIB_MOUNT_FLAG_STREAM_INTERFACE_WINDOWS) return LOOKUP_FLAG_ADS_OK; else return 0; } static inline int flags_writable(int open_flags) { return open_flags & (O_RDWR | O_WRONLY); } static int alloc_wimlib_fd(struct lookup_table_entry *lte, struct wimlib_fd **fd_ret) { if (lte->num_opened_fds == lte->num_allocated_fds) { struct wimlib_fd **fds; if (lte->num_allocated_fds > 0xffff - 8) return -ENFILE; fds = CALLOC(lte->num_allocated_fds + 8, sizeof(lte->fds[0])); if (!fds) return -ENOMEM; memcpy(fds, lte->fds, lte->num_allocated_fds * sizeof(lte->fds[0])); FREE(lte->fds); lte->fds = fds; } for (u16 i = 0; ; i++) { struct wimlib_fd *fd = lte->fds[i]; if (!fd) { fd = CALLOC(1, sizeof(*fd)); if (!fd) return -ENOMEM; fd->staging_fd = -1; fd->idx = i; fd->lte = lte; lte->fds[i] = fd; *fd_ret = fd; return 0; } } } static int close_wimlib_fd(struct wimlib_fd *fd) { struct lookup_table_entry *lte = fd->lte; wimlib_assert(lte); wimlib_assert(lte->num_opened_fds); if (lte->staging_file_name) { wimlib_assert(fd->staging_fd != -1); if (close(fd->staging_fd) != 0) return -errno; } if (--lte->num_opened_fds == 0 && lte->refcnt == 0) free_lookup_table_entry(lte); lte->fds[fd->idx] = NULL; FREE(fd); return 0; } /* Creates a new staging file and returns its file descriptor opened for * writing. * * @name_ret: A location into which the a pointer to the newly allocated name of * the staging file is stored. * @return: The file descriptor for the new file. Returns -1 and sets errno on * error, for any reason possible from the creat() function. */ static int create_staging_file(char **name_ret, int open_flags) { size_t name_len; char *name; struct stat stbuf; int fd; int errno_save; name_len = staging_dir_name_len + 1 + WIM_HASH_SIZE; name = MALLOC(name_len + 1); if (!name) { errno = ENOMEM; return -1; } do { memcpy(name, staging_dir_name, staging_dir_name_len); name[staging_dir_name_len] = '/'; randomize_char_array_with_alnum(name + staging_dir_name_len + 1, WIM_HASH_SIZE); name[name_len] = '\0'; /* Just in case, verify that the randomly generated name doesn't name an * existing file, and try again if so */ } while (stat(name, &stbuf) == 0); if (errno != ENOENT) /* other error! */ return -1; /* doesn't exist--- ok */ DEBUG("Creating staging file `%s'", name); fd = open(name, open_flags | O_CREAT | O_TRUNC, 0600); if (fd == -1) { errno_save = errno; FREE(name); errno = errno_save; } else { *name_ret = name; } return fd; } /* * Extract a WIM resource to the staging directory. * * We need to: * - Create a staging file for the WIM resource * - Extract the resource to it * - Create a new lte for the file resource * - Transfer fds from the old lte to the new lte, but * only if they share the same hard link group as this * dentry */ static int extract_resource_to_staging_dir(struct dentry *dentry, struct lookup_table_entry **lte, off_t size) { char *staging_file_name; int ret; int fd; struct lookup_table_entry *old_lte, *new_lte; size_t link_group_size; old_lte = *lte; fd = create_staging_file(&staging_file_name, O_WRONLY); if (fd == -1) return -errno; if (old_lte) ret = extract_resource_to_fd(w, &old_lte->resource_entry, fd, size); else ret = 0; if (ret != 0 || close(fd) != 0) { if (errno != 0) ret = -errno; else ret = -EIO; close(fd); unlink(staging_file_name); FREE(staging_file_name); return ret; } link_group_size = dentry_link_group_size(dentry); if (old_lte) { if (link_group_size == old_lte->refcnt) { /* This hard link group is the only user of the lookup * table entry, so we can re-use it. */ lookup_table_remove(w->lookup_table, old_lte); new_lte = old_lte; } else { /* Split a hard link group away from the "lookup table * entry" hard link group (i.e. we had two hard link * groups that were identical, but now we are changing * one of them) */ /* XXX The ADS really complicate things here and not * everything is going to work correctly yet. For * example it could be the same that a file contains two * file streams that are identical and therefore share * the same lookup table entry despite the fact that the * streams themselves are not hardlinked. */ wimlib_assert(old_lte->refcnt > link_group_size); new_lte = new_lookup_table_entry(); if (!new_lte) return -ENOMEM; u16 num_transferred_fds = 0; for (u16 i = 0; i < old_lte->num_allocated_fds; i++) { if (old_lte->fds[i] && old_lte->fds[i]->dentry->hard_link == dentry->hard_link) { num_transferred_fds++; } } new_lte->fds = MALLOC(num_transferred_fds * sizeof(new_lte->fds[0])); if (!new_lte->fds) { free_lookup_table_entry(new_lte); return -ENOMEM; } u16 j = 0; for (u16 i = 0; i < old_lte->num_allocated_fds; i++) { if (old_lte->fds[i] && old_lte->fds[i]->dentry->hard_link == dentry->hard_link) { struct wimlib_fd *fd = old_lte->fds[i]; old_lte->fds[i] = NULL; fd->lte = new_lte; fd->idx = j; new_lte->fds[j] = fd; } } old_lte->refcnt -= link_group_size; old_lte->num_opened_fds -= j; new_lte->num_opened_fds = j; } } new_lte->resource_entry.original_size = size; new_lte->refcnt = link_group_size; randomize_byte_array(new_lte->hash, WIM_HASH_SIZE); new_lte->staging_file_name = staging_file_name; lookup_table_insert(w->lookup_table, new_lte); *lte = new_lte; return 0; } /* * Creates a randomly named staging directory and returns its name into the * static variable staging_dir_name. * * If the staging directory cannot be created, staging_dir_name is set to NULL. * */ static void make_staging_dir() { /* XXX Give the user an option of where to stage files */ static char prefix[] = "wimlib-staging-"; static const size_t prefix_len = 15; static const size_t suffix_len = 10; size_t pwd_len = strlen(working_directory); staging_dir_name_len = pwd_len + 1 + prefix_len + suffix_len; staging_dir_name = MALLOC(staging_dir_name_len + 1); if (!staging_dir_name) { ERROR("Out of memory"); return; } memcpy(staging_dir_name, working_directory, pwd_len); staging_dir_name[pwd_len] = '/'; memcpy(staging_dir_name + pwd_len + 1, prefix, prefix_len); randomize_char_array_with_alnum(staging_dir_name + pwd_len + 1 + prefix_len, suffix_len); staging_dir_name[staging_dir_name_len] = '\0'; if (mkdir(staging_dir_name, 0700) != 0) { ERROR_WITH_ERRNO("Failed to create temporary directory `%s'", staging_dir_name); FREE(staging_dir_name); staging_dir_name = NULL; } } static int remove_file_or_directory(const char *fpath, const struct stat *sb, int typeflag, struct FTW *ftwbuf) { if (remove(fpath) == 0) return 0; else return WIMLIB_ERR_DELETE_STAGING_DIR; } /* * Deletes the staging directory and all the files contained in it. */ static inline int delete_staging_dir() { int ret; ret = nftw(staging_dir_name, remove_file_or_directory,10, FTW_DEPTH); staging_dir_name = NULL; return ret; } /* Name and message queue descriptors for message queues between the filesystem * daemon process and the unmount process. These are used when the filesystem * is unmounted and the process running wimlib_mount() (i.e. the `imagex * unmount' command) needs to communicate with the filesystem daemon running * fuse_main() (i.e. that spawned by the `imagex mount' or `imagex mountrw' * commands */ static char *unmount_to_daemon_mq_name; static char *daemon_to_unmount_mq_name; static int unmount_to_daemon_mq; static int daemon_to_unmount_mq; /* Simple function that returns the concatenation of 4 strings. */ static char *strcat_dup(const char *s1, const char *s2, const char *s3, const char *s4) { size_t len = strlen(s1) + strlen(s2) + strlen(s3) + strlen(s4) + 1; char *p = MALLOC(len); if (!p) return NULL; *p = '\0'; strcat(p, s1); strcat(p, s2); strcat(p, s3); strcat(p, s4); return p; } /* Removes trailing forward slashes in a string. */ static void remove_trailing_slashes(char *s) { long len = strlen(s); for (long i = len - 1; i >= 1; i--) { if (s[i] == '/') s[i] = '\0'; else break; } } /* Changes forward slashes to underscores in a string. */ static void s_slashes_underscores_g(char *s) { while (*s) { if (*s == '/') *s = '_'; s++; } } /* * Opens two POSIX message queue: one for sending messages from the unmount * process to the daemon process, and one to go the other way. The names of the * message queues, which must be system-wide unique, are be based on the mount * point. (There of course is still a possibility of a collision if one were to * unmount two identically named directories simultaneously...) * * @daemon specifies whether the calling process is the filesystem daemon or the * unmount process. */ static int open_message_queues(bool daemon) { static const char *slash = "/"; static const char *prefix = "wimlib-"; static const char *u2d_suffix = "unmount-to-daemon-mq"; static const char *d2u_suffix = "daemon-to-unmount-mq"; const char *mount_dir_basename = path_basename(mount_dir); int flags; int ret; unmount_to_daemon_mq_name = strcat_dup(slash, mount_dir_basename, prefix, u2d_suffix); if (!unmount_to_daemon_mq_name) { ERROR("Out of memory"); return WIMLIB_ERR_NOMEM; } daemon_to_unmount_mq_name = strcat_dup(slash, mount_dir_basename, prefix, d2u_suffix); if (!daemon_to_unmount_mq_name) { ERROR("Out of memory"); ret = WIMLIB_ERR_NOMEM; goto err1; } remove_trailing_slashes(unmount_to_daemon_mq_name); remove_trailing_slashes(daemon_to_unmount_mq_name); s_slashes_underscores_g(unmount_to_daemon_mq_name + 1); s_slashes_underscores_g(daemon_to_unmount_mq_name + 1); if (daemon) flags = O_RDONLY | O_CREAT; else flags = O_WRONLY | O_CREAT; unmount_to_daemon_mq = mq_open(unmount_to_daemon_mq_name, flags, 0700, NULL); if (unmount_to_daemon_mq == -1) { ERROR_WITH_ERRNO("mq_open()"); ret = WIMLIB_ERR_MQUEUE; goto err2; } if (daemon) flags = O_WRONLY | O_CREAT; else flags = O_RDONLY | O_CREAT; daemon_to_unmount_mq = mq_open(daemon_to_unmount_mq_name, flags, 0700, NULL); if (daemon_to_unmount_mq == -1) { ERROR_WITH_ERRNO("mq_open()"); ret = WIMLIB_ERR_MQUEUE; goto err3; } return 0; err3: mq_close(unmount_to_daemon_mq); mq_unlink(unmount_to_daemon_mq_name); err2: FREE(daemon_to_unmount_mq_name); err1: FREE(unmount_to_daemon_mq_name); return ret; } static int mq_get_msgsize(mqd_t mq) { static const char *msgsize_max_file = "/proc/sys/fs/mqueue/msgsize_max"; FILE *fp; struct mq_attr attr; int msgsize; if (mq_getattr(unmount_to_daemon_mq, &attr) == 0) { msgsize = attr.mq_msgsize; } else { ERROR_WITH_ERRNO("mq_getattr()"); ERROR("Attempting to read %s", msgsize_max_file); fp = fopen(msgsize_max_file, "rb"); if (fp) { if (fscanf(fp, "%d", &msgsize) != 1) { ERROR("Assuming message size of 8192"); msgsize = 8192; } fclose(fp); } else { ERROR_WITH_ERRNO("Failed to open the file `%s'", msgsize_max_file); ERROR("Assuming message size of 8192"); msgsize = 8192; } } return msgsize; } /* Closes the message queues, which are allocated in static variables */ static void close_message_queues() { mq_close(unmount_to_daemon_mq); mq_close(daemon_to_unmount_mq); mq_unlink(unmount_to_daemon_mq_name); mq_unlink(daemon_to_unmount_mq_name); } static int wimfs_access(const char *path, int mask) { /* XXX Permissions not implemented */ return 0; } /* Closes the staging file descriptor associated with the lookup table entry, if * it is opened. */ static int close_lte_fds(struct lookup_table_entry *lte, void *ignore) { for (u16 i = 0; i < lte->num_opened_fds; i++) { if (lte->fds[i] && lte->fds[i]->staging_fd != -1) { if (close(lte->fds[i]->staging_fd) != 0) { ERROR_WITH_ERRNO("Failed close file `%s'", lte->staging_file_name); return WIMLIB_ERR_WRITE; } } } return 0; } /* Calculates the SHA1 sum for @dentry if its file resource is in a staging * file. Updates the SHA1 sum in the dentry and the lookup table entry. If * there is already a lookup table entry with the same checksum, increment its * reference count and destroy the lookup entry with the updated checksum. */ static int calculate_sha1sum_for_staging_file(struct dentry *dentry, void *_lookup_table) { struct lookup_table *lookup_table = _lookup_table; u8 *hash = dentry->hash; u16 i = 0; while (1) { struct lookup_table_entry *lte = __lookup_resource(lookup_table, hash); if (lte && lte->staging_file_name) { struct lookup_table_entry *existing; int ret; DEBUG("Calculating SHA1 hash for file `%s'", dentry->file_name_utf8); ret = sha1sum(lte->staging_file_name, lte->hash); if (ret != 0) return ret; lookup_table_unlink(lookup_table, lte); memcpy(hash, lte->hash, WIM_HASH_SIZE); existing = __lookup_resource(lookup_table, hash); if (existing) { DEBUG("Merging duplicate lookup table entries for file " "`%s'", dentry->file_name_utf8); free_lookup_table_entry(lte); existing->refcnt++; } else { lookup_table_insert(lookup_table, lte); } } if (i == dentry->num_ads) break; hash = dentry->ads_entries[i].hash; i++; } return 0; } /* Overwrites the WIM file, with changes saved. */ static int rebuild_wim(WIMStruct *w, bool check_integrity) { int ret; struct dentry *root; root = wim_root_dentry(w); DEBUG("Closing all staging file descriptors."); /* Close all the staging file descriptors. */ ret = for_lookup_table_entry(w->lookup_table, close_lte_fds, NULL); if (ret != 0) { ERROR("Failed to close all staging files"); return ret; } DEBUG("Calculating SHA1 checksums for all new staging files."); /* Calculate SHA1 checksums for all staging files, and merge unnecessary * lookup table entries. */ ret = for_dentry_in_tree(root, calculate_sha1sum_for_staging_file, w->lookup_table); if (ret != 0) { ERROR("Failed to calculate new SHA1 checksums"); return ret; } xml_update_image_info(w, w->current_image); ret = wimlib_overwrite(w, check_integrity); if (ret != 0) { ERROR("Failed to commit changes"); return ret; } return ret; } /* Called when the filesystem is unmounted. */ static void wimfs_destroy(void *p) { /* For read-write mounts, the `imagex unmount' command, which is * running in a separate process and is executing the * wimlib_unmount() function, will send this process a byte * through a message queue that indicates whether the --commit * option was specified or not. */ int msgsize; struct timespec timeout; struct timeval now; ssize_t bytes_received; int ret; char commit; char check_integrity; char status; ret = open_message_queues(true); if (ret != 0) exit(1); msgsize = mq_get_msgsize(unmount_to_daemon_mq); char msg[msgsize]; msg[0] = 0; msg[1] = 0; /* Wait at most 3 seconds before giving up and discarding changes. */ gettimeofday(&now, NULL); timeout.tv_sec = now.tv_sec + 3; timeout.tv_nsec = now.tv_usec * 1000; DEBUG("Waiting for message telling us whether to commit or not, and " "whether to include integrity checks."); bytes_received = mq_timedreceive(unmount_to_daemon_mq, msg, msgsize, NULL, &timeout); commit = msg[0]; check_integrity = msg[1]; if (bytes_received == -1) { if (errno == ETIMEDOUT) { ERROR("Timed out."); } else { ERROR_WITH_ERRNO("mq_timedreceive()"); } ERROR("Not committing."); } else { DEBUG("Received message: [%d %d]", msg[0], msg[1]); } status = 0; if (mount_flags & WIMLIB_MOUNT_FLAG_READWRITE) { if (commit) { status = chdir(working_directory); if (status != 0) { ERROR_WITH_ERRNO("chdir()"); status = WIMLIB_ERR_NOTDIR; goto done; } status = rebuild_wim(w, (check_integrity != 0)); } ret = delete_staging_dir(); if (ret != 0) { ERROR_WITH_ERRNO("Failed to delete the staging " "directory"); if (status == 0) status = ret; } } done: ret = mq_send(daemon_to_unmount_mq, &status, 1, 1); if (ret == -1) ERROR_WITH_ERRNO("Failed to send status to unmount process"); close_message_queues(); } static int wimfs_ftruncate(const char *path, off_t size, struct fuse_file_info *fi) { struct wimlib_fd *fd = (struct wimlib_fd*)fi->fh; int ret = ftruncate(fd->staging_fd, size); if (ret != 0) return ret; fd->lte->resource_entry.original_size = size; return 0; } /* * Fills in a `struct stat' that corresponds to a file or directory in the WIM. */ static int wimfs_getattr(const char *path, struct stat *stbuf) { struct dentry *dentry = get_dentry(w, path); if (!dentry) return -ENOENT; dentry_to_stbuf(dentry, stbuf, w->lookup_table); return 0; } /* * Create a directory in the WIM. * @mode is currently ignored. */ static int wimfs_mkdir(const char *path, mode_t mode) { struct dentry *parent; struct dentry *newdir; const char *basename; parent = get_parent_dentry(w, path); if (!parent) return -ENOENT; if (!dentry_is_directory(parent)) return -ENOTDIR; basename = path_basename(path); if (get_dentry_child_with_name(parent, basename)) return -EEXIST; newdir = new_dentry(basename); newdir->attributes |= FILE_ATTRIBUTE_DIRECTORY; link_dentry(newdir, parent); return 0; } /* Creates a regular file. */ static int wimfs_mknod(const char *path, mode_t mode, dev_t rdev) { const char *stream_name; if ((mount_flags & WIMLIB_MOUNT_FLAG_STREAM_INTERFACE_WINDOWS) && (stream_name = path_stream_name(path))) { struct ads_entry *new_entry; struct dentry *dentry; dentry = get_dentry(w, path); if (!dentry || !dentry_is_regular_file(dentry)) return -ENOENT; if (dentry_get_ads_entry(dentry, stream_name)) return -EEXIST; new_entry = dentry_add_ads(dentry, stream_name); if (!new_entry) return -ENOENT; } else { struct dentry *dentry, *parent; const char *basename; /* Make sure that the parent of @path exists and is a directory, and * that the dentry named by @path does not already exist. */ parent = get_parent_dentry(w, path); if (!parent) return -ENOENT; if (!dentry_is_directory(parent)) return -ENOTDIR; basename = path_basename(path); if (get_dentry_child_with_name(parent, path)) return -EEXIST; dentry = new_dentry(basename); link_dentry(dentry, parent); } return 0; } /* Open a file. */ static int wimfs_open(const char *path, struct fuse_file_info *fi) { struct dentry *dentry; struct lookup_table_entry *lte; u8 *dentry_hash; int ret; struct wimlib_fd *fd; ret = lookup_resource(w, path, get_lookup_flags(), &dentry, <e, &dentry_hash); if (ret != 0) return ret; if (!lte) { /* Empty file with no lookup-table entry. This is fine if it's * a read-only filesystem. Otherwise we need to create a lookup * table entry so that we can keep track of the file descriptors * (this is important in case someone opens the file for * writing) */ if (!(mount_flags & WIMLIB_MOUNT_FLAG_READWRITE)) { fi->fh = 0; return 0; } ret = extract_resource_to_staging_dir(dentry, <e, lte->resource_entry.original_size); if (ret != 0) return ret; } ret = alloc_wimlib_fd(lte, &fd); if (ret != 0) return ret; fd->dentry = dentry; /* The file resource may be in the staging directory (read-write * mounts only) or in the WIM. If it's in the staging * directory, we need to open a native file descriptor for the * corresponding file. Otherwise, we can read the file resource * directly from the WIM file if we are opening it read-only, * but we need to extract the resource to the staging directory * if we are opening it writable. */ if (flags_writable(fi->flags) && !lte->staging_file_name) { ret = extract_resource_to_staging_dir(dentry, <e, lte->resource_entry.original_size); if (ret != 0) return ret; } if (lte->staging_file_name) { fd->staging_fd = open(lte->staging_file_name, fi->flags); if (fd->staging_fd == -1) { close_wimlib_fd(fd); return -errno; } } fi->fh = (uint64_t)fd; return 0; } /* Opens a directory. */ static int wimfs_opendir(const char *path, struct fuse_file_info *fi) { struct dentry *dentry; dentry = get_dentry(w, path); if (!dentry || !dentry_is_directory(dentry)) return -ENOTDIR; fi->fh = (uint64_t)dentry; return 0; } /* * Read data from a file in the WIM or in the staging directory. */ static int wimfs_read(const char *path, char *buf, size_t size, off_t offset, struct fuse_file_info *fi) { struct wimlib_fd *fd = (struct wimlib_fd*)fi->fh; if (!fd) { /* Empty file with no lookup table entry on read-only mounted * WIM */ wimlib_assert(!(mount_flags & WIMLIB_MOUNT_FLAG_READWRITE)); return 0; } if (fd->lte->staging_file_name) { /* Read from staging file */ wimlib_assert(fd->staging_fd != -1); ssize_t ret; if (lseek(fd->staging_fd, offset, SEEK_SET) == -1) return -errno; ret = read(fd->staging_fd, buf, size); if (ret == -1) return -errno; return ret; } else { /* Read from WIM */ struct resource_entry *res_entry; int ctype; res_entry = &fd->lte->resource_entry; ctype = wim_resource_compression_type(w, res_entry); if (offset > res_entry->original_size) return -EOVERFLOW; size = min(size, res_entry->original_size - offset); if (read_resource(w->fp, res_entry->size, res_entry->original_size, res_entry->offset, ctype, size, offset, buf) != 0) return -EIO; return size; } } /* Fills in the entries of the directory specified by @path using the * FUSE-provided function @filler. */ static int wimfs_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offset, struct fuse_file_info *fi) { struct dentry *parent, *child; parent = (struct dentry*)fi->fh; child = parent->children; filler(buf, ".", NULL, 0); filler(buf, "..", NULL, 0); if (!child) return 0; do { if (filler(buf, child->file_name_utf8, NULL, 0)) return 0; child = child->next; } while (child != parent->children); return 0; } static int wimfs_readlink(const char *path, char *buf, size_t buf_len) { struct dentry *dentry = get_dentry(w, path); int ret; if (!dentry) return -ENOENT; if (!dentry_is_symlink(dentry)) return -EINVAL; ret = dentry_readlink(dentry, buf, buf_len, w); if (ret > 0) ret = 0; return ret; } /* Close a file. */ static int wimfs_release(const char *path, struct fuse_file_info *fi) { int ret; struct wimlib_fd *fd = (struct wimlib_fd*)fi->fh; if (!fd) { /* Empty file with no lookup table entry on read-only mounted * WIM */ wimlib_assert(!(mount_flags & WIMLIB_MOUNT_FLAG_READWRITE)); return 0; } return close_wimlib_fd(fd); } /* Renames a file or directory. See rename (3) */ static int wimfs_rename(const char *from, const char *to) { struct dentry *src; struct dentry *dst; struct dentry *parent_of_dst; src = get_dentry(w, from); if (!src) return -ENOENT; dst = get_dentry(w, to); if (dst) { if (!dentry_is_directory(src)) { /* Cannot rename non-directory to directory. */ if (dentry_is_directory(dst)) return -EISDIR; } else { /* Cannot rename directory to a non-directory or a non-empty * directory */ if (!dentry_is_directory(dst)) return -ENOTDIR; if (dst->children != NULL) return -ENOTEMPTY; } parent_of_dst = dst->parent; unlink_dentry(dst); lookup_table_decrement_refcnt(w->lookup_table, dst->hash); free_dentry(dst); } else { parent_of_dst = get_parent_dentry(w, to); if (!parent_of_dst) return -ENOENT; } unlink_dentry(src); change_dentry_name(src, path_basename(to)); link_dentry(src, parent_of_dst); /*calculate_dentry_full_path(src);*/ return 0; } /* Remove a directory */ static int wimfs_rmdir(const char *path) { struct dentry *dentry; dentry = get_dentry(w, path); if (!dentry) return -ENOENT; if (!dentry_is_empty_directory(dentry)) return -ENOTEMPTY; unlink_dentry(dentry); free_dentry(dentry); return 0; } /* Reduce the size of a file */ static int wimfs_truncate(const char *path, off_t size) { struct dentry *dentry; struct lookup_table_entry *lte; int ret; u8 *dentry_hash; ret = lookup_resource(w, path, get_lookup_flags(), &dentry, <e, &dentry_hash); if (ret != 0) return ret; if (!lte) /* Already a zero-length file */ return 0; if (lte->staging_file_name) { ret = truncate(lte->staging_file_name, size); if (ret != 0) return -errno; lte->resource_entry.original_size = size; } else { /* File in WIM. Extract it to the staging directory, but only * the first @size bytes of it. */ ret = extract_resource_to_staging_dir(dentry, <e, size); } dentry_update_all_timestamps(dentry); return ret; } /* Remove a regular file */ static int wimfs_unlink(const char *path) { struct dentry *dentry; struct lookup_table_entry *lte; int ret; u8 *dentry_hash; ret = lookup_resource(w, path, get_lookup_flags(), &dentry, <e, &dentry_hash); if (ret != 0) return ret; if (lte && lte->staging_file_name) if (unlink(lte->staging_file_name) != 0) return -errno; if (dentry_hash == dentry->hash) { /* We are removing the full dentry including all alternate data * streams. */ const u8 *hash = dentry->hash; u16 i = 0; while (1) { lookup_table_decrement_refcnt(w->lookup_table, hash); if (i == dentry->num_ads) break; hash = dentry->ads_entries[i].hash; i++; } unlink_dentry(dentry); free_dentry(dentry); } else { /* We are removing an alternate data stream. */ struct ads_entry *cur_entry = dentry->ads_entries; while (cur_entry->hash != dentry_hash) cur_entry++; lookup_table_decrement_refcnt(w->lookup_table, cur_entry->hash); dentry_remove_ads(dentry, cur_entry); } /* Beware: The lookup table entry(s) may still be referenced by users * that have opened the corresponding streams. They are freed later in * wimfs_release() when the last file user has closed the stream. */ return 0; } /* Change the timestamp on a file dentry. * * There is no distinction between a file and its alternate data streams here. */ static int wimfs_utimens(const char *path, const struct timespec tv[2]) { struct dentry *dentry = get_dentry(w, path); if (!dentry) return -ENOENT; time_t last_access_t = (tv[0].tv_nsec == UTIME_NOW) ? time(NULL) : tv[0].tv_sec; dentry->last_access_time = unix_timestamp_to_ms(last_access_t); time_t last_mod_t = (tv[1].tv_nsec == UTIME_NOW) ? time(NULL) : tv[1].tv_sec; dentry->last_write_time = unix_timestamp_to_ms(last_mod_t); return 0; } /* Writes to a file in the WIM filesystem. * It may be an alternate data stream, but here we don't even notice because we * just get a lookup table entry. */ static int wimfs_write(const char *path, const char *buf, size_t size, off_t offset, struct fuse_file_info *fi) { struct wimlib_fd *fd = (struct wimlib_fd*)fi->fh; int ret; wimlib_assert(fd->lte); wimlib_assert(fd->lte->staging_file_name); wimlib_assert(fd->staging_fd != -1); /* Write the data. */ ret = write(fd->staging_fd, buf, size); if (ret == -1) return -errno; /* The file has been modified, so all its timestamps must be * updated. */ dentry_update_all_timestamps(fd->dentry); return ret; } static struct fuse_operations wimfs_oper = { .access = wimfs_access, .destroy = wimfs_destroy, .ftruncate = wimfs_ftruncate, .getattr = wimfs_getattr, .mkdir = wimfs_mkdir, .mknod = wimfs_mknod, .open = wimfs_open, .opendir = wimfs_opendir, .read = wimfs_read, .readdir = wimfs_readdir, .readlink = wimfs_readlink, .release = wimfs_release, .rename = wimfs_rename, .rmdir = wimfs_rmdir, .truncate = wimfs_truncate, .unlink = wimfs_unlink, .utimens = wimfs_utimens, .write = wimfs_write, }; /* Mounts a WIM file. */ WIMLIBAPI int wimlib_mount(WIMStruct *wim, int image, const char *dir, int flags) { int argc = 0; char *argv[6]; int ret; char *p; DEBUG("Mount: wim = %p, image = %d, dir = %s, flags = %d, ", wim, image, dir, flags); if (!dir) return WIMLIB_ERR_INVALID_PARAM; ret = wimlib_select_image(wim, image); if (ret != 0) return ret; if (flags & WIMLIB_MOUNT_FLAG_READWRITE) wim_get_current_image_metadata(wim)->modified = true; if (!(flags & (WIMLIB_MOUNT_FLAG_STREAM_INTERFACE_NONE | WIMLIB_MOUNT_FLAG_STREAM_INTERFACE_XATTR | WIMLIB_MOUNT_FLAG_STREAM_INTERFACE_WINDOWS))) flags |= WIMLIB_MOUNT_FLAG_STREAM_INTERFACE_XATTR; mount_dir = dir; working_directory = getcwd(NULL, 0); if (!working_directory) { ERROR_WITH_ERRNO("Could not determine current directory"); return WIMLIB_ERR_NOTDIR; } p = STRDUP(dir); if (!p) return WIMLIB_ERR_NOMEM; argv[argc++] = "mount"; argv[argc++] = p; argv[argc++] = "-s"; /* disable multi-threaded operation */ if (flags & WIMLIB_MOUNT_FLAG_DEBUG) { argv[argc++] = "-d"; } if (!(flags & WIMLIB_MOUNT_FLAG_READWRITE)) { argv[argc++] = "-o"; argv[argc++] = "ro"; } else { make_staging_dir(); if (!staging_dir_name) { FREE(p); return WIMLIB_ERR_MKDIR; } } #ifdef ENABLE_DEBUG { int i; DEBUG("FUSE command line (argc = %d): ", argc); for (i = 0; i < argc; i++) { fputs(argv[i], stdout); putchar(' '); } putchar('\n'); fflush(stdout); } #endif /* Set static variables. */ w = wim; mount_flags = flags; ret = fuse_main(argc, argv, &wimfs_oper, NULL); return (ret == 0) ? 0 : WIMLIB_ERR_FUSE; } /* * Unmounts the WIM file that was previously mounted on @dir by using * wimlib_mount(). */ WIMLIBAPI int wimlib_unmount(const char *dir, int flags) { pid_t pid; int status; int ret; char msg[2]; struct timeval now; struct timespec timeout; int msgsize; int errno_save; /* Execute `fusermount -u', which is installed setuid root, to unmount * the WIM. * * FUSE does not yet implement synchronous unmounts. This means that * fusermount -u will return before the filesystem daemon returns from * wimfs_destroy(). This is partly what we want, because we need to * send a message from this process to the filesystem daemon telling * whether --commit was specified or not. However, after that, the * unmount process must wait for the filesystem daemon to finish writing * the WIM file. */ mount_dir = dir; pid = fork(); if (pid == -1) { ERROR_WITH_ERRNO("Failed to fork()"); return WIMLIB_ERR_FORK; } if (pid == 0) { execlp("fusermount", "fusermount", "-u", dir, NULL); ERROR_WITH_ERRNO("Failed to execute `fusermount'"); return WIMLIB_ERR_FUSERMOUNT; } ret = waitpid(pid, &status, 0); if (ret == -1) { ERROR_WITH_ERRNO("Failed to wait for fusermount process to " "terminate"); return WIMLIB_ERR_FUSERMOUNT; } if (status != 0) { ERROR("fusermount exited with status %d", status); return WIMLIB_ERR_FUSERMOUNT; } /* Open message queues between the unmount process and the * filesystem daemon. */ ret = open_message_queues(false); if (ret != 0) return ret; /* Send a message to the filesystem saying whether to commit or * not. */ msg[0] = (flags & WIMLIB_UNMOUNT_FLAG_COMMIT) ? 1 : 0; msg[1] = (flags & WIMLIB_UNMOUNT_FLAG_CHECK_INTEGRITY) ? 1 : 0; DEBUG("Sending message: %s, %s", (msg[0] == 0) ? "don't commit" : "commit", (msg[1] == 0) ? "don't check" : "check"); ret = mq_send(unmount_to_daemon_mq, msg, 2, 1); if (ret == -1) { ERROR("Failed to notify filesystem daemon whether we want to " "commit changes or not"); close_message_queues(); return WIMLIB_ERR_MQUEUE; } /* Wait for a message from the filesytem daemon indicating whether the * filesystem was unmounted successfully (0) or an error occurred (1). * This may take a long time if a big WIM file needs to be rewritten. */ /* Wait at most 600??? seconds before giving up and returning false. * Either it's a really big WIM file, or (more likely) the * filesystem daemon has crashed or failed for some reason. * * XXX come up with some method to determine if the filesystem * daemon has really crashed or not. */ gettimeofday(&now, NULL); timeout.tv_sec = now.tv_sec + 600; timeout.tv_nsec = now.tv_usec * 1000; msgsize = mq_get_msgsize(daemon_to_unmount_mq); char mailbox[msgsize]; mailbox[0] = 0; DEBUG("Waiting for message telling us whether the unmount was " "successful or not."); ret = mq_timedreceive(daemon_to_unmount_mq, mailbox, msgsize, NULL, &timeout); errno_save = errno; close_message_queues(); if (ret == -1) { if (errno_save == ETIMEDOUT) { ERROR("Timed out- probably the filesystem daemon " "crashed and the WIM was not written " "successfully."); return WIMLIB_ERR_TIMEOUT; } else { ERROR("mq_receive(): %s", strerror(errno_save)); return WIMLIB_ERR_MQUEUE; } } DEBUG("Received message: %s", (mailbox[0] == 0) ? "Unmount OK" : "Unmount Failed"); if (mailbox[0] != 0) ERROR("Unmount failed"); return mailbox[0]; } #else /* WITH_FUSE */ static inline int mount_unsupported_error() { ERROR("WIMLIB was compiled with --without-fuse, which disables support " "for mounting WIMs."); return WIMLIB_ERR_UNSUPPORTED; } WIMLIBAPI int wimlib_unmount(const char *dir, int flags) { return mount_unsupported_error(); } WIMLIBAPI int wimlib_mount(WIMStruct *wim_p, int image, const char *dir, int flags) { return mount_unsupported_error(); } #endif /* WITH_FUSE */