/* * 9p synthetic file system support * * Copyright IBM, Corp. 2011 * * Authors: * Malahal Naineni <malahal@us.ibm.com> * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> * * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. * */ #include "qemu/osdep.h" #include "9p.h" #include "fsdev/qemu-fsdev.h" #include "9p-synth.h" #include "qemu/rcu.h" #include "qemu/rcu_queue.h" #include "qemu/cutils.h" /* Root node for synth file system */ static V9fsSynthNode synth_root = { .name = "/", .actual_attr = { .mode = 0555 | S_IFDIR, .nlink = 1, }, .attr = &synth_root.actual_attr, }; static QemuMutex synth_mutex; static int synth_node_count; /* set to 1 when the synth fs is ready */ static int synth_fs; static V9fsSynthNode *v9fs_add_dir_node(V9fsSynthNode *parent, int mode, const char *name, V9fsSynthNodeAttr *attr, int inode) { V9fsSynthNode *node; /* Add directory type and remove write bits */ mode = ((mode & 0777) | S_IFDIR) & ~(S_IWUSR | S_IWGRP | S_IWOTH); node = g_malloc0(sizeof(V9fsSynthNode)); if (attr) { /* We are adding .. or . entries */ node->attr = attr; node->attr->nlink++; } else { node->attr = &node->actual_attr; node->attr->inode = inode; node->attr->nlink = 1; /* We don't allow write to directories */ node->attr->mode = mode; node->attr->write = NULL; node->attr->read = NULL; } node->private = node; pstrcpy(node->name, sizeof(node->name), name); QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling); return node; } int qemu_v9fs_synth_mkdir(V9fsSynthNode *parent, int mode, const char *name, V9fsSynthNode **result) { int ret; V9fsSynthNode *node, *tmp; if (!synth_fs) { return EAGAIN; } if (!name || (strlen(name) >= NAME_MAX)) { return EINVAL; } if (!parent) { parent = &synth_root; } qemu_mutex_lock(&synth_mutex); QLIST_FOREACH(tmp, &parent->child, sibling) { if (!strcmp(tmp->name, name)) { ret = EEXIST; goto err_out; } } /* Add the name */ node = v9fs_add_dir_node(parent, mode, name, NULL, synth_node_count++); v9fs_add_dir_node(node, parent->attr->mode, "..", parent->attr, parent->attr->inode); v9fs_add_dir_node(node, node->attr->mode, ".", node->attr, node->attr->inode); *result = node; ret = 0; err_out: qemu_mutex_unlock(&synth_mutex); return ret; } int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode, const char *name, v9fs_synth_read read, v9fs_synth_write write, void *arg) { int ret; V9fsSynthNode *node, *tmp; if (!synth_fs) { return EAGAIN; } if (!name || (strlen(name) >= NAME_MAX)) { return EINVAL; } if (!parent) { parent = &synth_root; } qemu_mutex_lock(&synth_mutex); QLIST_FOREACH(tmp, &parent->child, sibling) { if (!strcmp(tmp->name, name)) { ret = EEXIST; goto err_out; } } /* Add file type and remove write bits */ mode = ((mode & 0777) | S_IFREG); node = g_malloc0(sizeof(V9fsSynthNode)); node->attr = &node->actual_attr; node->attr->inode = synth_node_count++; node->attr->nlink = 1; node->attr->read = read; node->attr->write = write; node->attr->mode = mode; node->private = arg; pstrcpy(node->name, sizeof(node->name), name); QLIST_INSERT_HEAD_RCU(&parent->child, node, sibling); ret = 0; err_out: qemu_mutex_unlock(&synth_mutex); return ret; } static void synth_fill_statbuf(V9fsSynthNode *node, struct stat *stbuf) { stbuf->st_dev = 0; stbuf->st_ino = node->attr->inode; stbuf->st_mode = node->attr->mode; stbuf->st_nlink = node->attr->nlink; stbuf->st_uid = 0; stbuf->st_gid = 0; stbuf->st_rdev = 0; stbuf->st_size = 0; stbuf->st_blksize = 0; stbuf->st_blocks = 0; stbuf->st_atime = 0; stbuf->st_mtime = 0; stbuf->st_ctime = 0; } static int synth_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf) { V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data; synth_fill_statbuf(node, stbuf); return 0; } static int synth_fstat(FsContext *fs_ctx, int fid_type, V9fsFidOpenState *fs, struct stat *stbuf) { V9fsSynthOpenState *synth_open = fs->private; synth_fill_statbuf(synth_open->node, stbuf); return 0; } static int synth_opendir(FsContext *ctx, V9fsPath *fs_path, V9fsFidOpenState *fs) { V9fsSynthOpenState *synth_open; V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data; synth_open = g_malloc(sizeof(*synth_open)); synth_open->node = node; node->open_count++; fs->private = synth_open; return 0; } static int synth_closedir(FsContext *ctx, V9fsFidOpenState *fs) { V9fsSynthOpenState *synth_open = fs->private; V9fsSynthNode *node = synth_open->node; node->open_count--; g_free(synth_open); fs->private = NULL; return 0; } static off_t synth_telldir(FsContext *ctx, V9fsFidOpenState *fs) { V9fsSynthOpenState *synth_open = fs->private; return synth_open->offset; } static void synth_seekdir(FsContext *ctx, V9fsFidOpenState *fs, off_t off) { V9fsSynthOpenState *synth_open = fs->private; synth_open->offset = off; } static void synth_rewinddir(FsContext *ctx, V9fsFidOpenState *fs) { synth_seekdir(ctx, fs, 0); } static void synth_direntry(V9fsSynthNode *node, struct dirent *entry, off_t off) { strcpy(entry->d_name, node->name); entry->d_ino = node->attr->inode; entry->d_off = off + 1; } static struct dirent *synth_get_dentry(V9fsSynthNode *dir, struct dirent *entry, off_t off) { int i = 0; V9fsSynthNode *node; rcu_read_lock(); QLIST_FOREACH(node, &dir->child, sibling) { /* This is the off child of the directory */ if (i == off) { break; } i++; } rcu_read_unlock(); if (!node) { /* end of directory */ return NULL; } synth_direntry(node, entry, off); return entry; } static struct dirent *synth_readdir(FsContext *ctx, V9fsFidOpenState *fs) { struct dirent *entry; V9fsSynthOpenState *synth_open = fs->private; V9fsSynthNode *node = synth_open->node; entry = synth_get_dentry(node, &synth_open->dent, synth_open->offset); if (entry) { synth_open->offset++; } return entry; } static int synth_open(FsContext *ctx, V9fsPath *fs_path, int flags, V9fsFidOpenState *fs) { V9fsSynthOpenState *synth_open; V9fsSynthNode *node = *(V9fsSynthNode **)fs_path->data; synth_open = g_malloc(sizeof(*synth_open)); synth_open->node = node; node->open_count++; fs->private = synth_open; return 0; } static int synth_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name, int flags, FsCred *credp, V9fsFidOpenState *fs) { errno = ENOSYS; return -1; } static int synth_close(FsContext *ctx, V9fsFidOpenState *fs) { V9fsSynthOpenState *synth_open = fs->private; V9fsSynthNode *node = synth_open->node; node->open_count--; g_free(synth_open); fs->private = NULL; return 0; } static ssize_t synth_pwritev(FsContext *ctx, V9fsFidOpenState *fs, const struct iovec *iov, int iovcnt, off_t offset) { int i, count = 0, wcount; V9fsSynthOpenState *synth_open = fs->private; V9fsSynthNode *node = synth_open->node; if (!node->attr->write) { errno = EPERM; return -1; } for (i = 0; i < iovcnt; i++) { wcount = node->attr->write(iov[i].iov_base, iov[i].iov_len, offset, node->private); offset += wcount; count += wcount; /* If we wrote less than requested. we are done */ if (wcount < iov[i].iov_len) { break; } } return count; } static ssize_t synth_preadv(FsContext *ctx, V9fsFidOpenState *fs, const struct iovec *iov, int iovcnt, off_t offset) { int i, count = 0, rcount; V9fsSynthOpenState *synth_open = fs->private; V9fsSynthNode *node = synth_open->node; if (!node->attr->read) { errno = EPERM; return -1; } for (i = 0; i < iovcnt; i++) { rcount = node->attr->read(iov[i].iov_base, iov[i].iov_len, offset, node->private); offset += rcount; count += rcount; /* If we read less than requested. we are done */ if (rcount < iov[i].iov_len) { break; } } return count; } static int synth_truncate(FsContext *ctx, V9fsPath *path, off_t offset) { errno = ENOSYS; return -1; } static int synth_chmod(FsContext *fs_ctx, V9fsPath *path, FsCred *credp) { errno = EPERM; return -1; } static int synth_mknod(FsContext *fs_ctx, V9fsPath *path, const char *buf, FsCred *credp) { errno = EPERM; return -1; } static int synth_mkdir(FsContext *fs_ctx, V9fsPath *path, const char *buf, FsCred *credp) { errno = EPERM; return -1; } static ssize_t synth_readlink(FsContext *fs_ctx, V9fsPath *path, char *buf, size_t bufsz) { errno = ENOSYS; return -1; } static int synth_symlink(FsContext *fs_ctx, const char *oldpath, V9fsPath *newpath, const char *buf, FsCred *credp) { errno = EPERM; return -1; } static int synth_link(FsContext *fs_ctx, V9fsPath *oldpath, V9fsPath *newpath, const char *buf) { errno = EPERM; return -1; } static int synth_rename(FsContext *ctx, const char *oldpath, const char *newpath) { errno = EPERM; return -1; } static int synth_chown(FsContext *fs_ctx, V9fsPath *path, FsCred *credp) { errno = EPERM; return -1; } static int synth_utimensat(FsContext *fs_ctx, V9fsPath *path, const struct timespec *buf) { errno = EPERM; return 0; } static int synth_remove(FsContext *ctx, const char *path) { errno = EPERM; return -1; } static int synth_fsync(FsContext *ctx, int fid_type, V9fsFidOpenState *fs, int datasync) { errno = ENOSYS; return 0; } static int synth_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf) { stbuf->f_type = 0xABCD; stbuf->f_bsize = 512; stbuf->f_blocks = 0; stbuf->f_files = synth_node_count; stbuf->f_namelen = NAME_MAX; return 0; } static ssize_t synth_lgetxattr(FsContext *ctx, V9fsPath *path, const char *name, void *value, size_t size) { errno = ENOTSUP; return -1; } static ssize_t synth_llistxattr(FsContext *ctx, V9fsPath *path, void *value, size_t size) { errno = ENOTSUP; return -1; } static int synth_lsetxattr(FsContext *ctx, V9fsPath *path, const char *name, void *value, size_t size, int flags) { errno = ENOTSUP; return -1; } static int synth_lremovexattr(FsContext *ctx, V9fsPath *path, const char *name) { errno = ENOTSUP; return -1; } static int synth_name_to_path(FsContext *ctx, V9fsPath *dir_path, const char *name, V9fsPath *target) { V9fsSynthNode *node; V9fsSynthNode *dir_node; /* "." and ".." are not allowed */ if (!strcmp(name, ".") || !strcmp(name, "..")) { errno = EINVAL; return -1; } if (!dir_path) { dir_node = &synth_root; } else { dir_node = *(V9fsSynthNode **)dir_path->data; } if (!strcmp(name, "/")) { node = dir_node; goto out; } /* search for the name in the childern */ rcu_read_lock(); QLIST_FOREACH(node, &dir_node->child, sibling) { if (!strcmp(node->name, name)) { break; } } rcu_read_unlock(); if (!node) { errno = ENOENT; return -1; } out: /* Copy the node pointer to fid */ target->data = g_malloc(sizeof(void *)); memcpy(target->data, &node, sizeof(void *)); target->size = sizeof(void *); return 0; } static int synth_renameat(FsContext *ctx, V9fsPath *olddir, const char *old_name, V9fsPath *newdir, const char *new_name) { errno = EPERM; return -1; } static int synth_unlinkat(FsContext *ctx, V9fsPath *dir, const char *name, int flags) { errno = EPERM; return -1; } static int synth_init(FsContext *ctx) { QLIST_INIT(&synth_root.child); qemu_mutex_init(&synth_mutex); /* Add "." and ".." entries for root */ v9fs_add_dir_node(&synth_root, synth_root.attr->mode, "..", synth_root.attr, synth_root.attr->inode); v9fs_add_dir_node(&synth_root, synth_root.attr->mode, ".", synth_root.attr, synth_root.attr->inode); /* Mark the subsystem is ready for use */ synth_fs = 1; return 0; } FileOperations synth_ops = { .init = synth_init, .lstat = synth_lstat, .readlink = synth_readlink, .close = synth_close, .closedir = synth_closedir, .open = synth_open, .opendir = synth_opendir, .rewinddir = synth_rewinddir, .telldir = synth_telldir, .readdir = synth_readdir, .seekdir = synth_seekdir, .preadv = synth_preadv, .pwritev = synth_pwritev, .chmod = synth_chmod, .mknod = synth_mknod, .mkdir = synth_mkdir, .fstat = synth_fstat, .open2 = synth_open2, .symlink = synth_symlink, .link = synth_link, .truncate = synth_truncate, .rename = synth_rename, .chown = synth_chown, .utimensat = synth_utimensat, .remove = synth_remove, .fsync = synth_fsync, .statfs = synth_statfs, .lgetxattr = synth_lgetxattr, .llistxattr = synth_llistxattr, .lsetxattr = synth_lsetxattr, .lremovexattr = synth_lremovexattr, .name_to_path = synth_name_to_path, .renameat = synth_renameat, .unlinkat = synth_unlinkat, };