Add fanotify API wrappers (#2194)

* Add fanotify API wrappers

* Review/fix enum comments

* Rename has_compile_version to check_version

* Fix lint unsafe_block_in_unsafe_fn

* Rename fanotify OFlags to EventFFlags

* Use existing function at_rawfd from fcntl

* Add missing feature guard for docs

* Change FanotifyEvent struct to a simple wrapper over libc structure

* Change FanotifyResponse struct to a simple wrapper over libc structure

* Cast pointer with function 'cast' instead of 'as'

* Add FAN_REPORT_PIDFD and FAN_REPORT_TID fanotify init flags

Cargo.toml

@@ -42,6 +42,7 @@ aio = ["pin-utils"]
 dir = ["fs"]
 env = []
 event = []
+fanotify = []
 feature = []
 fs = []
 hostname = []

changelog/2194.added.md

@@ -0,0 +1 @@
+Added new fanotify API: wrappers for `fanotify_init` and `fanotify_mark`

src/fcntl.rs

@@ -64,10 +64,14 @@ libc_bitflags! {
     }
 }
 
-#[cfg(any(feature = "fs", feature = "term"))]
+#[cfg(any(
+    feature = "fs",
+    feature = "term",
+    all(feature = "fanotify", target_os = "linux")
+))]
 libc_bitflags!(
     /// Configuration options for opened files.
-    #[cfg_attr(docsrs, doc(cfg(any(feature = "fs", feature = "term"))))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "fs", feature = "term", all(feature = "fanotify", target_os = "linux")))))]
     pub struct OFlag: c_int {
         /// Mask for the access mode of the file.
         O_ACCMODE;
@@ -194,7 +198,8 @@ libc_bitflags!(
 /// Computes the raw fd consumed by a function of the form `*at`.
 #[cfg(any(
     all(feature = "fs", not(target_os = "redox")),
-    all(feature = "process", any(target_os = "android", target_os = "linux"))
+    all(feature = "process", any(target_os = "android", target_os = "linux")),
+    all(feature = "fanotify", target_os = "linux")
 ))]
 pub(crate) fn at_rawfd(fd: Option<RawFd>) -> raw::c_int {
     fd.unwrap_or(libc::AT_FDCWD)

src/lib.rs

@@ -12,6 +12,7 @@
 //! * `dir` - Stuff relating to directory iteration
 //! * `env` - Manipulate environment variables
 //! * `event` - Event-driven APIs, like `kqueue` and `epoll`
+//! * `fanotify` - Linux's `fanotify` filesystem events monitoring API
 //! * `feature` - Query characteristics of the OS at runtime
 //! * `fs` - File system functionality
 //! * `hostname` - Get and set the system's hostname
@@ -53,6 +54,7 @@
         feature = "dir",
         feature = "env",
         feature = "event",
+        feature = "fanotify",
         feature = "feature",
         feature = "fs",
         feature = "hostname",