--- /dev/null
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2016 Nikolaus Rath <Nikolaus@rath.org>
+
+ This program can be distributed under the terms of the GNU GPL.
+ See the file COPYING.
+
+ This example implements a file system with a single file whose
+ file name changes dynamically to reflect the current time.
+
+ It illustrates the use of the fuse_lowlevel_notify_inval_entry()
+ function.
+
+ To see the effect, first start the file system with the
+ ``--no-notify``
+
+ $ timefs --update-interval=1 --timeout 30 --no-notify mnt/
+
+ Observe that `ls` always prints the correct directory contents
+ (since `readdir` output is not cached)::
+
+ $ ls mnt; sleep 1; ls mnt; sleep 1; ls mnt
+ Time_is_15h_48m_33s current_time
+ Time_is_15h_48m_34s current_time
+ Time_is_15h_48m_35s current_time
+
+ However, if you try to access a file by name the kernel will
+ report that it still exists:
+
+ $ file=$(ls mnt/); echo $file
+ Time_is_15h_50m_09s
+ $ sleep 5; stat mnt/$file
+ File: ‘mnt/Time_is_15h_50m_09s’
+ Size: 32 Blocks: 0 IO Block: 4096 regular file
+ Device: 2ah/42d Inode: 3 Links: 1
+ Access: (0444/-r--r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
+ Access: 1969-12-31 16:00:00.000000000 -0800
+ Modify: 1969-12-31 16:00:00.000000000 -0800
+ Change: 1969-12-31 16:00:00.000000000 -0800
+ Birth: -
+
+ Only once the kernel cache timeout has been reached will the stat
+ call fail:
+
+ $ sleep 30; stat mnt/$file
+ stat: cannot stat ‘mnt/Time_is_15h_50m_09s’: No such file or directory
+
+ In contrast, if you enable notifications you will be unable to stat
+ the file as soon as the file system updates its name:
+
+ $ timefs --update-interval=1 --timeout 30 --no-notify mnt/
+ $ file=$(ls mnt/); stat mnt/$file
+ File: ‘mnt/Time_is_20h_42m_11s’
+ Size: 0 Blocks: 0 IO Block: 4096 regular empty file
+ Device: 2ah/42d Inode: 2 Links: 1
+ Access: (0000/----------) Uid: ( 0/ root) Gid: ( 0/ root)
+ Access: 1969-12-31 16:00:00.000000000 -0800
+ Modify: 1969-12-31 16:00:00.000000000 -0800
+ Change: 1969-12-31 16:00:00.000000000 -0800
+ Birth: -
+ $ sleep 1; stat mnt/$file
+ stat: cannot stat ‘mnt/Time_is_20h_42m_11s’: No such file or directory
+
+*/
+
+#define FUSE_USE_VERSION 30
+
+#include <config.h>
+
+#include <fuse_lowlevel.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <pthread.h>
+
+#define MAX_STR_LEN 128
+static char file_name[MAX_STR_LEN];
+static fuse_ino_t file_ino = 2;
+static int lookup_cnt = 0;
+
+/* Command line parsing */
+struct options {
+ int no_notify;
+ float timeout;
+ int update_interval;
+};
+static struct options options = {
+ .timeout = 5,
+ .no_notify = 0,
+ .update_interval = 1,
+};
+
+#define OPTION(t, p) \
+ { t, offsetof(struct options, p), 1 }
+static const struct fuse_opt option_spec[] = {
+ OPTION("--no-notify", no_notify),
+ OPTION("--update-interval=%d", update_interval),
+ OPTION("--timeout=%f", timeout),
+ FUSE_OPT_END
+};
+
+static int opt_proc(void *data, const char *arg, int key,
+ struct fuse_args *outargs) {
+ (void) outargs; (void) data; (void) arg;
+ (void) key;
+ return 1;
+}
+
+static int tfs_stat(fuse_ino_t ino, struct stat *stbuf) {
+ stbuf->st_ino = ino;
+ if (ino == FUSE_ROOT_ID) {
+ stbuf->st_mode = S_IFDIR | 0755;
+ stbuf->st_nlink = 1;
+ }
+
+ else if (ino == file_ino) {
+ stbuf->st_mode = S_IFREG | 0000;
+ stbuf->st_nlink = 1;
+ stbuf->st_size = 0;
+ }
+
+ else
+ return -1;
+
+ return 0;
+}
+
+static void tfs_lookup(fuse_req_t req, fuse_ino_t parent,
+ const char *name) {
+ struct fuse_entry_param e;
+ memset(&e, 0, sizeof(e));
+
+ if (parent != FUSE_ROOT_ID)
+ goto err_out;
+ else if (strcmp(name, file_name) == 0) {
+ e.ino = file_ino;
+ lookup_cnt++;
+ } else
+ goto err_out;
+
+ e.attr_timeout = options.timeout;
+ e.entry_timeout = options.timeout;
+ if (tfs_stat(e.ino, &e.attr) != 0)
+ goto err_out;
+ fuse_reply_entry(req, &e);
+ return;
+
+err_out:
+ fuse_reply_err(req, ENOENT);
+}
+
+static void tfs_forget (fuse_req_t req, fuse_ino_t ino,
+ uint64_t nlookup) {
+ (void) req;
+ assert(ino == file_ino || ino == FUSE_ROOT_ID);
+ lookup_cnt -= nlookup;
+ fuse_reply_none(req);
+}
+
+
+static void tfs_getattr(fuse_req_t req, fuse_ino_t ino,
+ struct fuse_file_info *fi) {
+ struct stat stbuf;
+
+ (void) fi;
+
+ memset(&stbuf, 0, sizeof(stbuf));
+ if (tfs_stat(ino, &stbuf) != 0)
+ fuse_reply_err(req, ENOENT);
+ else
+ fuse_reply_attr(req, &stbuf, options.timeout);
+}
+
+struct dirbuf {
+ char *p;
+ size_t size;
+};
+
+static void dirbuf_add(fuse_req_t req, struct dirbuf *b, const char *name,
+ fuse_ino_t ino) {
+ struct stat stbuf;
+ size_t oldsize = b->size;
+ b->size += fuse_add_direntry(req, NULL, 0, name, NULL, 0);
+ b->p = (char *) realloc(b->p, b->size);
+ memset(&stbuf, 0, sizeof(stbuf));
+ stbuf.st_ino = ino;
+ fuse_add_direntry(req, b->p + oldsize, b->size - oldsize, name, &stbuf,
+ b->size);
+}
+
+#define min(x, y) ((x) < (y) ? (x) : (y))
+
+static int reply_buf_limited(fuse_req_t req, const char *buf, size_t bufsize,
+ off_t off, size_t maxsize) {
+ if (off < bufsize)
+ return fuse_reply_buf(req, buf + off,
+ min(bufsize - off, maxsize));
+ else
+ return fuse_reply_buf(req, NULL, 0);
+}
+
+static void tfs_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
+ off_t off, struct fuse_file_info *fi) {
+ (void) fi;
+
+ if (ino != FUSE_ROOT_ID)
+ fuse_reply_err(req, ENOTDIR);
+ else {
+ struct dirbuf b;
+
+ memset(&b, 0, sizeof(b));
+ dirbuf_add(req, &b, file_name, file_ino);
+ reply_buf_limited(req, b.p, b.size, off, size);
+ free(b.p);
+ }
+}
+
+static struct fuse_lowlevel_ops tfs_oper = {
+ .lookup = tfs_lookup,
+ .getattr = tfs_getattr,
+ .readdir = tfs_readdir,
+ .forget = tfs_forget,
+};
+
+static void* update_fs(void *data) {
+ struct fuse_session *se = (struct fuse_session*) data;
+ struct tm *now;
+ char *old_name;
+ time_t t;
+ ssize_t ret;
+
+ while(1) {
+ t = time(NULL);
+ now = localtime(&t);
+ assert(now != NULL);
+
+ old_name = strdup(file_name);
+ ret = strftime(file_name, MAX_STR_LEN,
+ "Time_is_%Hh_%Mm_%Ss", now);
+ assert(ret != 0);
+
+ if (!options.no_notify && lookup_cnt)
+ assert(fuse_lowlevel_notify_inval_entry
+ (se, FUSE_ROOT_ID, old_name, strlen(old_name)) == 0);
+ free(old_name);
+ sleep(options.update_interval);
+ }
+ return NULL;
+}
+
+int main(int argc, char *argv[]) {
+ struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
+ struct fuse_session *se;
+ struct fuse_cmdline_opts opts;
+ pthread_t updater;
+ int ret = -1;
+
+ if (fuse_opt_parse(&args, &options, option_spec,
+ opt_proc) == -1)
+ return 1;
+
+ if (fuse_parse_cmdline(&args, &opts) != 0)
+ return 1;
+ if (opts.show_help || opts.show_version) {
+ ret = 1;
+ goto err_out1;
+ }
+
+ se = fuse_session_new(&args, &tfs_oper,
+ sizeof(tfs_oper), NULL);
+ if (se == NULL)
+ goto err_out1;
+
+ if (fuse_set_signal_handlers(se) != 0)
+ goto err_out2;
+
+ if (fuse_session_mount(se, opts.mountpoint) != 0)
+ goto err_out3;
+
+ fuse_daemonize(opts.foreground);
+
+ /* Start thread to update file contents */
+ ret = pthread_create(&updater, NULL, update_fs, (void *)se);
+ if (ret != 0) {
+ fprintf(stderr, "pthread_create failed with %s\n",
+ strerror(ret));
+ goto err_out3;
+ }
+
+ /* Block until ctrl+c or fusermount -u */
+ if (opts.singlethread)
+ ret = fuse_session_loop(se);
+ else
+ ret = fuse_session_loop_mt(se);
+
+ fuse_session_unmount(se);
+err_out3:
+ fuse_remove_signal_handlers(se);
+err_out2:
+ fuse_session_destroy(se);
+err_out1:
+ free(opts.mountpoint);
+ fuse_opt_free_args(&args);
+
+ return ret ? 1 : 0;
+}
+
+
+/**
+ * Local Variables:
+ * mode: c
+ * indent-tabs-mode: nil
+ * c-basic-offset: 4
+ * End:
+ */
@pytest.mark.parametrize("name", ('timefs1', 'timefs2'))
@pytest.mark.parametrize("options", LL_OPTIONS)
@pytest.mark.parametrize("notify", (True, False))
-def test_timefs(tmpdir, name, options, notify):
+def test_timefs12(tmpdir, name, options, notify):
mnt_dir = str(tmpdir)
cmdline = base_cmdline + \
[ pjoin(basename, 'example', name),
else:
umount(mount_process, mnt_dir)
+@pytest.mark.parametrize("notify", (True, False))
+def test_timefs3(tmpdir, notify):
+ mnt_dir = str(tmpdir)
+ cmdline = base_cmdline + \
+ [ pjoin(basename, 'example', 'timefs3'),
+ '-f', '--update-interval=2',
+ '--timeout=4', mnt_dir ]
+ if not notify:
+ cmdline.append('--no-notify')
+ mount_process = subprocess.Popen(cmdline)
+ try:
+ wait_for_mount(mount_process, mnt_dir)
+ fname = pjoin(mnt_dir, os.listdir(mnt_dir)[0])
+ try:
+ os.stat(fname)
+ except FileNotFoundError:
+ # We may have hit a race condition
+ fname = pjoin(mnt_dir, os.listdir(mnt_dir)[0])
+ os.stat(fname)
+
+ safe_sleep(2)
+ if not notify:
+ os.stat(fname)
+ safe_sleep(4)
+ with pytest.raises(FileNotFoundError):
+ os.stat(fname)
+ except:
+ cleanup(mnt_dir)
+ raise
+ else:
+ umount(mount_process, mnt_dir)
+
def checked_unlink(filename, path, isdir=False):
fullname = pjoin(path, filename)
if isdir:
projects / qemu-gpiodev / libfuse.git / commitdiff