Added timefs3 to test notify_inval_entry.

Fixes #32.

2 files changed, 322 insertions, 1 deletions

diff --git a/example/Makefile.am b/example/Makefile.am
index c619067..40f882b 100644
--- a/example/Makefile.am
+++ b/example/Makefile.am
@@ -3,7 +3,8 @@
 AM_CPPFLAGS = -I$(top_srcdir)/include -D_REENTRANT
 noinst_HEADERS = fioc.h
 noinst_PROGRAMS = fusexmp fusexmp_fh null hello hello_ll fioc fioclient \
-		  fsel fselclient cusexmp fuse_lo-plus timefs1 timefs2
+		  fsel fselclient cusexmp fuse_lo-plus timefs1 timefs2 \
+		  timefs3
 
 LDADD = ../lib/libfuse3.la
 fusexmp_fh_LDADD = ../lib/libfuse3.la @fusexmp_fh_libs@
diff --git a/example/timefs3.c b/example/timefs3.c
new file mode 100644
index 0000000..0a52e0f
--- /dev/null
+++ b/example/timefs3.c
@@ -0,0 +1,320 @@
+/*
+  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:
+ */