readahead: implement minimal readahead logic based on fanotify(), mincore() and reada...

[elogind.git] / src / linux / fanotify.h

diff --git a/src/linux/fanotify.h b/src/linux/fanotify.h
new file mode 100644 (file)
index 0000000..63531a6
--- /dev/null
+++ b/src/linux/fanotify.h
@@ -0,0 +1,98 @@
+#ifndef _LINUX_FANOTIFY_H
+#define _LINUX_FANOTIFY_H
+
+#include <linux/types.h>
+
+/* the following events that user-space can register for */
+#define FAN_ACCESS             0x00000001      /* File was accessed */
+#define FAN_MODIFY             0x00000002      /* File was modified */
+#define FAN_CLOSE_WRITE                0x00000008      /* Unwrittable file closed */
+#define FAN_CLOSE_NOWRITE      0x00000010      /* Writtable file closed */
+#define FAN_OPEN               0x00000020      /* File was opened */
+
+#define FAN_EVENT_ON_CHILD     0x08000000      /* interested in child events */
+
+/* FIXME currently Q's have no limit.... */
+#define FAN_Q_OVERFLOW         0x00004000      /* Event queued overflowed */
+
+#define FAN_OPEN_PERM          0x00010000      /* File open in perm check */
+#define FAN_ACCESS_PERM                0x00020000      /* File accessed in perm check */
+
+/* helper events */
+#define FAN_CLOSE              (FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE) /* close */
+
+/* flags used for fanotify_init() */
+#define FAN_CLOEXEC            0x00000001
+#define FAN_NONBLOCK           0x00000002
+
+#define FAN_ALL_INIT_FLAGS     (FAN_CLOEXEC | FAN_NONBLOCK)
+
+/* flags used for fanotify_modify_mark() */
+#define FAN_MARK_ADD           0x00000001
+#define FAN_MARK_REMOVE                0x00000002
+#define FAN_MARK_DONT_FOLLOW   0x00000004
+#define FAN_MARK_ONLYDIR       0x00000008
+#define FAN_MARK_MOUNT         0x00000010
+#define FAN_MARK_IGNORED_MASK  0x00000020
+#define FAN_MARK_IGNORED_SURV_MODIFY   0x00000040
+#define FAN_MARK_FLUSH         0x00000080
+
+#define FAN_ALL_MARK_FLAGS     (FAN_MARK_ADD |\
+                                FAN_MARK_REMOVE |\
+                                FAN_MARK_DONT_FOLLOW |\
+                                FAN_MARK_ONLYDIR |\
+                                FAN_MARK_MOUNT |\
+                                FAN_MARK_IGNORED_MASK |\
+                                FAN_MARK_IGNORED_SURV_MODIFY)
+
+/*
+ * All of the events - we build the list by hand so that we can add flags in
+ * the future and not break backward compatibility.  Apps will get only the
+ * events that they originally wanted.  Be sure to add new events here!
+ */
+#define FAN_ALL_EVENTS (FAN_ACCESS |\
+                       FAN_MODIFY |\
+                       FAN_CLOSE |\
+                       FAN_OPEN)
+
+/*
+ * All events which require a permission response from userspace
+ */
+#define FAN_ALL_PERM_EVENTS (FAN_OPEN_PERM |\
+                            FAN_ACCESS_PERM)
+
+#define FAN_ALL_OUTGOING_EVENTS        (FAN_ALL_EVENTS |\
+                                FAN_ALL_PERM_EVENTS |\
+                                FAN_Q_OVERFLOW)
+
+#define FANOTIFY_METADATA_VERSION      2
+
+struct fanotify_event_metadata {
+       __u32 event_len;
+       __u32 vers;
+       __u64 mask;
+       __s32 fd;
+       __s32 pid;
+} __attribute__ ((packed));
+
+struct fanotify_response {
+       __s32 fd;
+       __u32 response;
+} __attribute__ ((packed));
+
+/* Legit userspace responses to a _PERM event */
+#define FAN_ALLOW      0x01
+#define FAN_DENY       0x02
+
+/* Helper functions to deal with fanotify_event_metadata buffers */
+#define FAN_EVENT_METADATA_LEN (sizeof(struct fanotify_event_metadata))
+
+#define FAN_EVENT_NEXT(meta, len) ((len) -= (meta)->event_len, \
+                                  (struct fanotify_event_metadata*)(((char *)(meta)) + \
+                                  (meta)->event_len))
+
+#define FAN_EVENT_OK(meta, len)        ((long)(len) >= (long)FAN_EVENT_METADATA_LEN && \
+                               (long)(meta)->event_len >= (long)FAN_EVENT_METADATA_LEN && \
+                               (long)(meta)->event_len <= (long)(len))
+
+#endif /* _LINUX_FANOTIFY_H */