fuse.c

UNIX/LINUX下面的用户文件系统

            fprintf(stderr, "OPEN[%llu] flags: 0x%x %s\n",
                    (unsigned long long) fi->fh, fi->flags, path);
        }
    } else
        reply_err(req, err);

    if (path)
        free(path);
    pthread_rwlock_unlock(&f->tree_lock);
}

static void fuse_lib_read(fuse_req_t req, fuse_ino_t ino, size_t size,
                          off_t off, struct fuse_file_info *fi)
{
    struct fuse *f = req_fuse_prepare(req);
    char *path;
    char *buf;
    int res;

    buf = (char *) malloc(size);
    if (buf == NULL) {
        reply_err(req, -ENOMEM);
        return;
    }

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        struct fuse_intr_data d;
        if (f->conf.debug)
            fprintf(stderr, "READ[%llu] %lu bytes from %llu\n",
                    (unsigned long long) fi->fh, (unsigned long) size,
                    (unsigned long long) off);

        fuse_prepare_interrupt(f, req, &d);
        res = fuse_fs_read(f->fs, path, buf, size, off, fi);
        fuse_finish_interrupt(f, req, &d);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);

    if (res >= 0) {
        if (f->conf.debug)
            fprintf(stderr, "   READ[%llu] %u bytes\n",
                    (unsigned long long)fi->fh, res);
        if ((size_t) res > size)
            fprintf(stderr, "fuse: read too many bytes");
        fuse_reply_buf(req, buf, res);
    } else
        reply_err(req, res);

    free(buf);
}

static void fuse_lib_write(fuse_req_t req, fuse_ino_t ino, const char *buf,
                       size_t size, off_t off, struct fuse_file_info *fi)
{
    struct fuse *f = req_fuse_prepare(req);
    char *path;
    int res;

    res = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        struct fuse_intr_data d;
        if (f->conf.debug)
            fprintf(stderr, "WRITE%s[%llu] %lu bytes to %llu\n",
                    fi->writepage ? "PAGE" : "", (unsigned long long) fi->fh,
                    (unsigned long) size, (unsigned long long) off);

        fuse_prepare_interrupt(f, req, &d);
        res = fuse_fs_write(f->fs, path, buf, size, off, fi);
        fuse_finish_interrupt(f, req, &d);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);

    if (res >= 0) {
        if (f->conf.debug)
            fprintf(stderr, "   WRITE%s[%llu] %u bytes\n",
                    fi->writepage ? "PAGE" : "", (unsigned long long) fi->fh,
                    res);
        if ((size_t) res > size)
            fprintf(stderr, "fuse: wrote too many bytes");
        fuse_reply_write(req, res);
    } else
        reply_err(req, res);
}

static void fuse_lib_fsync(fuse_req_t req, fuse_ino_t ino, int datasync,
                       struct fuse_file_info *fi)
{
    struct fuse *f = req_fuse_prepare(req);
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        struct fuse_intr_data d;
        if (f->conf.debug)
            fprintf(stderr, "FSYNC[%llu]\n", (unsigned long long) fi->fh);
        fuse_prepare_interrupt(f, req, &d);
        err = fuse_fs_fsync(f->fs, path, datasync, fi);
        fuse_finish_interrupt(f, req, &d);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_err(req, err);
}

static struct fuse_dh *get_dirhandle(const struct fuse_file_info *llfi,
                                     struct fuse_file_info *fi)
{
    struct fuse_dh *dh = (struct fuse_dh *) (uintptr_t) llfi->fh;
    memset(fi, 0, sizeof(struct fuse_file_info));
    fi->fh = dh->fh;
    fi->fh_old = dh->fh;
    return dh;
}

static void fuse_lib_opendir(fuse_req_t req, fuse_ino_t ino,
                       struct fuse_file_info *llfi)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_intr_data d;
    struct fuse_dh *dh;
    struct fuse_file_info fi;
    char *path;
    int err;

    dh = (struct fuse_dh *) malloc(sizeof(struct fuse_dh));
    if (dh == NULL) {
        reply_err(req, -ENOMEM);
        return;
    }
    memset(dh, 0, sizeof(struct fuse_dh));
    dh->fuse = f;
    dh->contents = NULL;
    dh->len = 0;
    dh->filled = 0;
    dh->nodeid = ino;
    fuse_mutex_init(&dh->lock);

    llfi->fh = (uintptr_t) dh;

    memset(&fi, 0, sizeof(fi));
    fi.flags = llfi->flags;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        fuse_prepare_interrupt(f, req, &d);
        err = fuse_fs_opendir(f->fs, path, &fi);
        fuse_finish_interrupt(f, req, &d);
        dh->fh = fi.fh;
    }
    if (!err) {
        if (fuse_reply_open(req, llfi) == -ENOENT) {
            /* The opendir syscall was interrupted, so it must be cancelled */
            fuse_prepare_interrupt(f, req, &d);
            fuse_fs_releasedir(f->fs, path, &fi);
            fuse_finish_interrupt(f, req, &d);
            pthread_mutex_destroy(&dh->lock);
            free(dh);
        }
    } else {
        reply_err(req, err);
        free(dh);
    }
    free(path);
    pthread_rwlock_unlock(&f->tree_lock);
}

static int extend_contents(struct fuse_dh *dh, unsigned minsize)
{
    if (minsize > dh->size) {
        char *newptr;
        unsigned newsize = dh->size;
        if (!newsize)
            newsize = 1024;
        while (newsize < minsize)
            newsize *= 2;

        newptr = (char *) realloc(dh->contents, newsize);
        if (!newptr) {
            dh->error = -ENOMEM;
            return -1;
        }
        dh->contents = newptr;
        dh->size = newsize;
    }
    return 0;
}

static int fill_dir(void *dh_, const char *name, const struct stat *statp,
                    off_t off)
{
    struct fuse_dh *dh = (struct fuse_dh *) dh_;
    struct stat stbuf;
    size_t newlen;

    if (statp)
        stbuf = *statp;
    else {
        memset(&stbuf, 0, sizeof(stbuf));
        stbuf.st_ino = FUSE_UNKNOWN_INO;
    }

    if (!dh->fuse->conf.use_ino) {
        stbuf.st_ino = FUSE_UNKNOWN_INO;
        if (dh->fuse->conf.readdir_ino) {
            struct node *node;
            pthread_mutex_lock(&dh->fuse->lock);
            node = lookup_node(dh->fuse, dh->nodeid, name);
            if (node)
                stbuf.st_ino  = (ino_t) node->nodeid;
            pthread_mutex_unlock(&dh->fuse->lock);
        }
    }

    if (off) {
        if (extend_contents(dh, dh->needlen) == -1)
            return 1;

        dh->filled = 0;
        newlen = dh->len + fuse_add_direntry(dh->req, dh->contents + dh->len,
                                             dh->needlen - dh->len, name,
                                             &stbuf, off);
        if (newlen > dh->needlen)
            return 1;
    } else {
        newlen = dh->len + fuse_add_direntry(dh->req, NULL, 0, name, NULL, 0);
        if (extend_contents(dh, newlen) == -1)
            return 1;

        fuse_add_direntry(dh->req, dh->contents + dh->len, dh->size - dh->len,
                          name, &stbuf, newlen);
    }
    dh->len = newlen;
    return 0;
}

static int readdir_fill(struct fuse *f, fuse_req_t req, fuse_ino_t ino,
                        size_t size, off_t off, struct fuse_dh *dh,
                        struct fuse_file_info *fi)
{
    int err = -ENOENT;
    char *path;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        struct fuse_intr_data d;

        dh->len = 0;
        dh->error = 0;
        dh->needlen = size;
        dh->filled = 1;
        dh->req = req;
        fuse_prepare_interrupt(f, req, &d);
        err = fuse_fs_readdir(f->fs, path, dh, fill_dir, off, fi);
        fuse_finish_interrupt(f, req, &d);
        dh->req = NULL;
        if (!err)
            err = dh->error;
        if (err)
            dh->filled = 0;
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    return err;
}

static void fuse_lib_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
                             off_t off, struct fuse_file_info *llfi)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_file_info fi;
    struct fuse_dh *dh = get_dirhandle(llfi, &fi);

    pthread_mutex_lock(&dh->lock);
    /* According to SUS, directory contents need to be refreshed on
       rewinddir() */
    if (!off)
        dh->filled = 0;

    if (!dh->filled) {
        int err = readdir_fill(f, req, ino, size, off, dh, &fi);
        if (err) {
            reply_err(req, err);
            goto out;
        }
    }
    if (dh->filled) {
        if (off < dh->len) {
            if (off + size > dh->len)
                size = dh->len - off;
        } else
            size = 0;
    } else {
        size = dh->len;
        off = 0;
    }
    fuse_reply_buf(req, dh->contents + off, size);
 out:
    pthread_mutex_unlock(&dh->lock);
}

static void fuse_lib_releasedir(fuse_req_t req, fuse_ino_t ino,
                            struct fuse_file_info *llfi)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_intr_data d;
    struct fuse_file_info fi;
    struct fuse_dh *dh = get_dirhandle(llfi, &fi);
    char *path;

    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    fuse_prepare_interrupt(f, req, &d);
    fuse_fs_releasedir(f->fs, path ? path : "-", &fi);
    fuse_finish_interrupt(f, req, &d);
    if (path)
        free(path);
    pthread_rwlock_unlock(&f->tree_lock);
    pthread_mutex_lock(&dh->lock);
    pthread_mutex_unlock(&dh->lock);
    pthread_mutex_destroy(&dh->lock);
    free(dh->contents);
    free(dh);
    reply_err(req, 0);
}

static void fuse_lib_fsyncdir(fuse_req_t req, fuse_ino_t ino, int datasync,
                          struct fuse_file_info *llfi)
{
    struct fuse *f = req_fuse_prepare(req);
    struct fuse_file_info fi;
    char *path;
    int err;

    get_dirhandle(llfi, &fi);

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        struct fuse_intr_data d;
        fuse_prepare_interrupt(f, req, &d);
        err = fuse_fs_fsyncdir(f->fs, path, datasync, &fi);
        fuse_finish_interrupt(f, req, &d);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_err(req, err);
}

static void fuse_lib_statfs(fuse_req_t req, fuse_ino_t ino)
{
    struct fuse *f = req_fuse_prepare(req);
    struct statvfs buf;
    char *path;
    int err;

    memset(&buf, 0, sizeof(buf));
    pthread_rwlock_rdlock(&f->tree_lock);
    if (!ino) {
        err = -ENOMEM;
        path = strdup("/");
    } else {
        err = -ENOENT;
        path = get_path(f, ino);
    }
    if (path) {
        struct fuse_intr_data d;
        fuse_prepare_interrupt(f, req, &d);
        err = fuse_fs_statfs(f->fs, path, &buf);
        fuse_finish_interrupt(f, req, &d);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);

    if (!err)
        fuse_reply_statfs(req, &buf);
    else
        reply_err(req, err);
}

static void fuse_lib_setxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
                              const char *value, size_t size, int flags)
{
    struct fuse *f = req_fuse_prepare(req);
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        struct fuse_intr_data d;
        fuse_prepare_interrupt(f, req, &d);
        err = fuse_fs_setxattr(f->fs, path, name, value, size, flags);
        fuse_finish_interrupt(f, req, &d);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    reply_err(req, err);
}

static int common_getxattr(struct fuse *f, fuse_req_t req, fuse_ino_t ino,
                           const char *name, char *value, size_t size)
{
    int err;
    char *path;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        struct fuse_intr_data d;
        fuse_prepare_interrupt(f, req, &d);
        err = fuse_fs_getxattr(f->fs, path, name, value, size);
        fuse_finish_interrupt(f, req, &d);
        free(path);
    }
    pthread_rwlock_unlock(&f->tree_lock);
    return err;
}

static void fuse_lib_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
                              size_t size)
{
    struct fuse *f = req_fuse_prepare(req);
    int res;

    if (size) {
        char *value = (char *) malloc(size);
        if (value == NULL) {
            reply_err(req, -ENOMEM);
            return;
        }
        res = common_getxattr(f, req, ino, name, value, size);
        if (res > 0)
            fuse_reply_buf(req, value, res);
        else
            reply_err(req, res);
        free(value);
    } else {
        res = common_getxattr(f, req, ino, name, NULL, 0);
        if (res >= 0)
            fuse_reply_xattr(req, res);
        else
            reply_err(req, res);
    }
}

static int common_listxattr(struct fuse *f, fuse_req_t req, fuse_ino_t ino,
                            char *list, size_t size)
{
    char *path;
    int err;

    err = -ENOENT;
    pthread_rwlock_rdlock(&f->tree_lock);
    path = get_path(f, ino);
    if (path != NULL) {
        struct fuse_intr_data d;
        fuse_prepare_interrupt(f, req, &d);
        err = fus