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-rw-r--r--example/notify_inval_inode.c365
1 files changed, 0 insertions, 365 deletions
diff --git a/example/notify_inval_inode.c b/example/notify_inval_inode.c
deleted file mode 100644
index cdea82d..0000000
--- a/example/notify_inval_inode.c
+++ /dev/null
@@ -1,365 +0,0 @@
-/*
- 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.
-*/
-
-/** @file
- *
- * This example implements a file system with a single file whose
- * contents change dynamically: it always contains the current time.
- *
- * While notify_store_retrieve.c uses fuse_lowlevel_notify_store() to
- * actively push the updated data into the kernel cache, this example
- * uses fuse_lowlevel_notify_inval_inode() to notify the kernel that
- * the cache has to be invalidated - but the kernel still has to
- * explicitly request the updated data on the next read.
- *
- * To see the effect, first start the file system with the
- * ``--no-notify`` option:
- *
- * $ notify_inval_inode --update-interval=1 --no-notify mnt/
- *
- * Observe that the output never changes, even though the file system
- * updates it once per second. This is because the contents are cached
- * in the kernel:
- *
- * $ for i in 1 2 3 4 5; do
- * > cat mnt/current_time
- * > sleep 1
- * > done
- * The current time is 15:58:18
- * The current time is 15:58:18
- * The current time is 15:58:18
- * The current time is 15:58:18
- * The current time is 15:58:18
- *
- * If you instead enable the notification functions, the changes become
- * visible:
- *
- * $ notify_inval_inode --update-interval=1 mnt/
- * $ for i in 1 2 3 4 5; do
- * > cat mnt/current_time
- * > sleep 1
- * > done
- * The current time is 15:58:40
- * The current time is 15:58:41
- * The current time is 15:58:42
- * The current time is 15:58:43
- * The current time is 15:58:44
- *
- * ## Compilation ##
- *
- * gcc -Wall notify_inval_inode.c `pkg-config fuse3 --cflags --libs` -o notify_inval_inode
- *
- * ## Source code ##
- * \include notify_inval_inode.c
- */
-
-
-#define FUSE_USE_VERSION 31
-
-#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>
-
-/* We can't actually tell the kernel that there is no
- timeout, so we just send a big value */
-#define NO_TIMEOUT 500000
-
-#define MAX_STR_LEN 128
-#define FILE_INO 2
-#define FILE_NAME "current_time"
-static char file_contents[MAX_STR_LEN];
-static int lookup_cnt = 0;
-static size_t file_size;
-
-/* Command line parsing */
-struct options {
- int no_notify;
- int update_interval;
-};
-static struct options options = {
- .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),
- FUSE_OPT_END
-};
-
-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 | 0444;
- stbuf->st_nlink = 1;
- stbuf->st_size = file_size;
- }
-
- 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 = NO_TIMEOUT;
- e.entry_timeout = NO_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;
- if(ino == FILE_INO)
- lookup_cnt -= nlookup;
- else
- assert(ino == FUSE_ROOT_ID);
- 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, NO_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 void tfs_open(fuse_req_t req, fuse_ino_t ino,
- struct fuse_file_info *fi) {
-
- /* Make cache persistent even if file is closed,
- this makes it easier to see the effects */
- fi->keep_cache = 1;
-
- if (ino == FUSE_ROOT_ID)
- fuse_reply_err(req, EISDIR);
- else if ((fi->flags & O_ACCMODE) != O_RDONLY)
- fuse_reply_err(req, EACCES);
- else if (ino == FILE_INO)
- fuse_reply_open(req, fi);
- else {
- // This should not happen
- fprintf(stderr, "Got open for non-existing inode!\n");
- fuse_reply_err(req, ENOENT);
- }
-}
-
-static void tfs_read(fuse_req_t req, fuse_ino_t ino, size_t size,
- off_t off, struct fuse_file_info *fi) {
- (void) fi;
-
- assert(ino == FILE_INO);
- reply_buf_limited(req, file_contents, file_size, off, size);
-}
-
-static struct fuse_lowlevel_ops tfs_oper = {
- .lookup = tfs_lookup,
- .getattr = tfs_getattr,
- .readdir = tfs_readdir,
- .open = tfs_open,
- .read = tfs_read,
- .forget = tfs_forget,
-};
-
-static void update_fs(void) {
- struct tm *now;
- time_t t;
- t = time(NULL);
- now = localtime(&t);
- assert(now != NULL);
-
- file_size = strftime(file_contents, MAX_STR_LEN,
- "The current time is %H:%M:%S\n", now);
- assert(file_size != 0);
-}
-
-static void* update_fs_loop(void *data) {
- struct fuse_session *se = (struct fuse_session*) data;
-
- while(1) {
- update_fs();
- if (!options.no_notify && lookup_cnt) {
- /* Only send notification if the kernel
- is aware of the inode */
- assert(fuse_lowlevel_notify_inval_inode
- (se, FILE_INO, 0, 0) == 0);
- }
- sleep(options.update_interval);
- }
- return NULL;
-}
-
-static void show_help(const char *progname)
-{
- printf("usage: %s [options] <mountpoint>\n\n", progname);
- printf("File-system specific options:\n"
- " --update-interval=<secs> Update-rate of file system contents\n"
- " --no-notify Disable kernel notifications\n"
- "\n");
-}
-
-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, NULL) == -1)
- return 1;
-
- if (fuse_parse_cmdline(&args, &opts) != 0) {
- ret = 1;
- goto err_out1;
- }
-
- if (opts.show_help) {
- show_help(argv[0]);
- fuse_cmdline_help();
- fuse_lowlevel_help();
- ret = 0;
- goto err_out1;
- } else if (opts.show_version) {
- printf("FUSE library version %s\n", fuse_pkgversion());
- fuse_lowlevel_version();
- ret = 0;
- goto err_out1;
- }
-
- /* Initial contents */
- update_fs();
-
- 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_loop, (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, opts.clone_fd);
-
- fuse_session_unmount(se);
-err_out3:
- fuse_remove_signal_handlers(se);
-err_out2:
- fuse_session_destroy(se);
-err_out1:
- fuse_opt_free_args(&args);
- free(opts.mountpoint);
-
- return ret ? 1 : 0;
-}
-
-
-/**
- * Local Variables:
- * mode: c
- * indent-tabs-mode: nil
- * c-basic-offset: 4
- * End:
- */
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