Commit 94552684 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Eric Paris

dnotify: ignore FS_EVENT_ON_CHILD

Mask off FS_EVENT_ON_CHILD in dnotify_handle_event().  Otherwise, when there
is more than one watch on a directory and dnotify_should_send_event()
succeeds, events with FS_EVENT_ON_CHILD set will trigger all watches and cause
spurious events.

This case was overlooked in commit e42e2773.

	#define _GNU_SOURCE

	#include <stdio.h>
	#include <stdlib.h>
	#include <unistd.h>
	#include <signal.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <fcntl.h>
	#include <string.h>

	static void create_event(int s, siginfo_t* si, void* p)
	{
		printf("create\n");
	}

	static void delete_event(int s, siginfo_t* si, void* p)
	{
		printf("delete\n");
	}

	int main (void) {
		struct sigaction action;
		char *tmpdir, *file;
		int fd1, fd2;

		sigemptyset (&action.sa_mask);
		action.sa_flags = SA_SIGINFO;

		action.sa_sigaction = create_event;
		sigaction (SIGRTMIN + 0, &action, NULL);

		action.sa_sigaction = delete_event;
		sigaction (SIGRTMIN + 1, &action, NULL);

	#	define TMPDIR "/tmp/test.XXXXXX"
		tmpdir = malloc(strlen(TMPDIR) + 1);
		strcpy(tmpdir, TMPDIR);
		mkdtemp(tmpdir);

	#	define TMPFILE "/file"
		file = malloc(strlen(tmpdir) + strlen(TMPFILE) + 1);
		sprintf(file, "%s/%s", tmpdir, TMPFILE);

		fd1 = open (tmpdir, O_RDONLY);
		fcntl(fd1, F_SETSIG, SIGRTMIN);
		fcntl(fd1, F_NOTIFY, DN_MULTISHOT | DN_CREATE);

		fd2 = open (tmpdir, O_RDONLY);
		fcntl(fd2, F_SETSIG, SIGRTMIN + 1);
		fcntl(fd2, F_NOTIFY, DN_MULTISHOT | DN_DELETE);

		if (fork()) {
			/* This triggers a create event */
			creat(file, 0600);
			/* This triggers a create and delete event (!) */
			unlink(file);
		} else {
			sleep(1);
			rmdir(tmpdir);
		}

		return 0;
	}
Signed-off-by: default avatarAndreas Gruenbacher <agruen@suse.de>
Signed-off-by: default avatarEric Paris <eparis@redhat.com>
parent 3de0ef4f
...@@ -91,6 +91,7 @@ static int dnotify_handle_event(struct fsnotify_group *group, ...@@ -91,6 +91,7 @@ static int dnotify_handle_event(struct fsnotify_group *group,
struct dnotify_struct *dn; struct dnotify_struct *dn;
struct dnotify_struct **prev; struct dnotify_struct **prev;
struct fown_struct *fown; struct fown_struct *fown;
__u32 test_mask = event->mask & ~FS_EVENT_ON_CHILD;
to_tell = event->to_tell; to_tell = event->to_tell;
...@@ -106,7 +107,7 @@ static int dnotify_handle_event(struct fsnotify_group *group, ...@@ -106,7 +107,7 @@ static int dnotify_handle_event(struct fsnotify_group *group,
spin_lock(&entry->lock); spin_lock(&entry->lock);
prev = &dnentry->dn; prev = &dnentry->dn;
while ((dn = *prev) != NULL) { while ((dn = *prev) != NULL) {
if ((dn->dn_mask & event->mask) == 0) { if ((dn->dn_mask & test_mask) == 0) {
prev = &dn->dn_next; prev = &dn->dn_next;
continue; continue;
} }
......
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