qemu-e2k/hw/9pfs/9p-synth.c

660 lines
17 KiB
C

/*
* 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.
*
*/
/*
* Not so fast! You might want to read the 9p developer docs first:
* https://wiki.qemu.org/Documentation/9p
*/
#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"
#include "sysemu/qtest.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_new0(V9fsSynthNode, 1);
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_LOCK_GUARD(&synth_mutex);
QLIST_FOREACH(tmp, &parent->child, sibling) {
if (!strcmp(tmp->name, name)) {
ret = EEXIST;
return ret;
}
}
/* 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;
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_LOCK_GUARD(&synth_mutex);
QLIST_FOREACH(tmp, &parent->child, sibling) {
if (!strcmp(tmp->name, name)) {
ret = EEXIST;
return ret;
}
}
/* Add file type and remove write bits */
mode = ((mode & 0777) | S_IFREG);
node = g_new0(V9fsSynthNode, 1);
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;
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;
/*
* V9fsSynthOpenState contains 'struct dirent' which have OS-specific
* properties, thus it's zero cleared on allocation here and below
* in synth_open.
*/
synth_open = g_new0(V9fsSynthOpenState, 1);
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)
{
size_t sz = strlen(node->name) + 1;
/*
* 'entry' is always inside of V9fsSynthOpenState which have NAME_MAX
* back padding. Ensure we do not overflow it.
*/
g_assert(sizeof(struct dirent) + NAME_MAX >=
offsetof(struct dirent, d_name) + sz);
memcpy(entry->d_name, node->name, sz);
entry->d_ino = node->attr->inode;
#ifdef CONFIG_DARWIN
entry->d_seekoff = off + 1;
#else
entry->d_off = off + 1;
#endif
}
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_new0(V9fsSynthOpenState, 1);
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;
#ifndef CONFIG_DARWIN
stbuf->f_namelen = NAME_MAX;
#endif
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 */
g_free(target->data);
target->data = g_memdup(&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 ssize_t v9fs_synth_qtest_write(void *buf, int len, off_t offset,
void *arg)
{
return 1;
}
static ssize_t v9fs_synth_qtest_flush_write(void *buf, int len, off_t offset,
void *arg)
{
bool should_block = !!*(uint8_t *)buf;
if (should_block) {
/* This will cause the server to call us again until we're cancelled */
errno = EINTR;
return -1;
}
return 1;
}
static int synth_init(FsContext *ctx, Error **errp)
{
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;
if (qtest_enabled()) {
V9fsSynthNode *node = NULL;
int i, ret;
/* Directory hierarchy for WALK test */
for (i = 0; i < P9_MAXWELEM; i++) {
char *name = g_strdup_printf(QTEST_V9FS_SYNTH_WALK_FILE, i);
ret = qemu_v9fs_synth_mkdir(node, 0700, name, &node);
assert(!ret);
g_free(name);
}
/* File for LOPEN test */
ret = qemu_v9fs_synth_add_file(NULL, 0, QTEST_V9FS_SYNTH_LOPEN_FILE,
NULL, NULL, ctx);
assert(!ret);
/* File for WRITE test */
ret = qemu_v9fs_synth_add_file(NULL, 0, QTEST_V9FS_SYNTH_WRITE_FILE,
NULL, v9fs_synth_qtest_write, ctx);
assert(!ret);
/* File for FLUSH test */
ret = qemu_v9fs_synth_add_file(NULL, 0, QTEST_V9FS_SYNTH_FLUSH_FILE,
NULL, v9fs_synth_qtest_flush_write,
ctx);
assert(!ret);
/* Directory for READDIR test */
{
V9fsSynthNode *dir = NULL;
ret = qemu_v9fs_synth_mkdir(
NULL, 0700, QTEST_V9FS_SYNTH_READDIR_DIR, &dir
);
assert(!ret);
for (i = 0; i < QTEST_V9FS_SYNTH_READDIR_NFILES; ++i) {
char *name = g_strdup_printf(
QTEST_V9FS_SYNTH_READDIR_FILE, i
);
ret = qemu_v9fs_synth_add_file(
dir, 0, name, NULL, NULL, ctx
);
assert(!ret);
g_free(name);
}
}
}
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,
};