From 5c7a82a1c8276a0ea67cdbdc5a917ec88bb1082a Mon Sep 17 00:00:00 2001 From: Daniel McCarney Date: Mon, 2 Mar 2020 17:50:37 -0500 Subject: linux: add fanotify(7) API bindings. The `fanotify` API[0] is a linux-specific API for notification and interception of filesystem events. In some ways it is similar to `inotify`, but with different advantages/tradeoffs. It is particularly well suited to full filesystem/mount monitoring (vs per directory) and for allowing/denying access to files (`inotify` lacks this capability). The `fanotify` API has been updated several times since it was enabled in Linux 2.6.37. Presently I've only included support for the original `fanotify` features, and the `FAN_MARK_FILESYSTEM` addition made in Linux 4.20. There are subsequent updates in 5.0 and 5.1 not covered in this initial commit. This commit adds the relevant constants and types from `uapi/linux/fanotify.h`[1] and two new functions (`fanotify_init`[2] and `fanotify_wrap`[3]) to `src/unix/linux_like/linux/mod.rs`. While I believe this API is also present on Android I have presently limited my attention to Linux. Although this commit focuses on Linux 4.20.x's `fanotify` API/constants I have skipped adding constants for `FAN_ALL_CLASS_BITS`, `FAN_ALL_INIT_FLAGS`, `FAN_ALL_MARK_FLAGS`, `FAN_ALL_EVENTS`, `FAN_ALL_PERM_EVENTS` and `FAN_ALL_OUTGOING_EVENTS` even though they are present in this kernel version's headers. These defines were deprecated[4] in later releases with instructions to not use them in new programs or extend them with new values. It would be a shame for new Rust programs to use deprecated #defines! [0]: http://man7.org/linux/man-pages/man7/fanotify.7.html [1]: https://github.com/torvalds/linux/blob/d54f4fba889b205e9cd8239182ca5d27d0ac3bc2/include/uapi/linux/fanotify.h [2]: http://man7.org/linux/man-pages/man2/fanotify_init.2.html [3]: http://man7.org/linux/man-pages/man2/fanotify_mark.2.html [4]: https://github.com/torvalds/linux/commit/23c9deeb3285d34fd243abb3d6b9f07db60c3cf4#diff-4c9ca62be6bf38cc08f7ea9daf16e379 --- libc-test/build.rs | 1 + src/unix/linux_like/linux/align.rs | 11 ++++++++ src/unix/linux_like/linux/gnu/mod.rs | 7 +++++ src/unix/linux_like/linux/mod.rs | 53 +++++++++++++++++++++++++++++++++++ src/unix/linux_like/linux/musl/mod.rs | 10 +++++++ src/unix/linux_like/linux/no_align.rs | 11 ++++++++ 6 files changed, 93 insertions(+) diff --git a/libc-test/build.rs b/libc-test/build.rs index 1f7152e42a..a1b7ad7f72 100644 --- a/libc-test/build.rs +++ b/libc-test/build.rs @@ -2258,6 +2258,7 @@ fn test_linux(target: &str) { "linux/sockios.h", "linux/vm_sockets.h", "sys/auxv.h", + "sys/fanotify.h", } // note: aio.h must be included before sys/mount.h diff --git a/src/unix/linux_like/linux/align.rs b/src/unix/linux_like/linux/align.rs index 09bf8c8535..01e00839d6 100644 --- a/src/unix/linux_like/linux/align.rs +++ b/src/unix/linux_like/linux/align.rs @@ -39,6 +39,17 @@ macro_rules! expand_align { #[doc(hidden)] size: [u8; ::__SIZEOF_PTHREAD_CONDATTR_T], } + + #[repr(align(8))] + pub struct fanotify_event_metadata { + pub event_len: __u32, + pub vers: __u8, + pub reserved: __u8, + pub metadata_len: __u16, + pub mask: __u64, + pub fd: ::c_int, + pub pid: ::c_int, + } } s_no_extra_traits! { diff --git a/src/unix/linux_like/linux/gnu/mod.rs b/src/unix/linux_like/linux/gnu/mod.rs index 48272f4bd8..9c3038bf7b 100644 --- a/src/unix/linux_like/linux/gnu/mod.rs +++ b/src/unix/linux_like/linux/gnu/mod.rs @@ -1206,6 +1206,13 @@ extern "C" { len: ::size_t, flags: ::c_uint, ) -> ::ssize_t; + pub fn fanotify_mark( + fd: ::c_int, + flags: ::c_uint, + mask: u64, + dirfd: ::c_int, + path: *const ::c_char, + ) -> ::c_int; } #[link(name = "util")] diff --git a/src/unix/linux_like/linux/mod.rs b/src/unix/linux_like/linux/mod.rs index 8a6a6f09fb..6a7b5e9610 100644 --- a/src/unix/linux_like/linux/mod.rs +++ b/src/unix/linux_like/linux/mod.rs @@ -477,6 +477,11 @@ s! { pub len: u32 } + pub struct fanotify_response { + pub fd: ::c_int, + pub response: __u32, + } + pub struct sockaddr_vm { pub svm_family: ::sa_family_t, pub svm_reserved1: ::c_ushort, @@ -2417,6 +2422,53 @@ pub const IN_ALL_EVENTS: u32 = IN_ACCESS pub const IN_CLOEXEC: ::c_int = O_CLOEXEC; pub const IN_NONBLOCK: ::c_int = O_NONBLOCK; +// uapi/linux/fanotify.h +pub const FAN_ACCESS: u64 = 0x0000_0001; +pub const FAN_MODIFY: u64 = 0x0000_0002; +pub const FAN_CLOSE_WRITE: u64 = 0x0000_0008; +pub const FAN_CLOSE_NOWRITE: u64 = 0x0000_0010; +pub const FAN_OPEN: u64 = 0x0000_0020; + +pub const FAN_Q_OVERFLOW: u64 = 0x0000_4000; + +pub const FAN_OPEN_PERM: u64 = 0x0001_0000; +pub const FAN_ACCESS_PERM: u64 = 0x0002_0000; + +pub const FAN_ONDIR: u64 = 0x4000_0000; + +pub const FAN_EVENT_ON_CHILD: u64 = 0x0800_0000; + +pub const FAN_CLOSE: u64 = FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE; + +pub const FAN_CLOEXEC: ::c_uint = 0x0000_0001; +pub const FAN_NONBLOCK: ::c_uint = 0x0000_0002; + +pub const FAN_CLASS_NOTIF: ::c_uint = 0x0000_0000; +pub const FAN_CLASS_CONTENT: ::c_uint = 0x0000_0004; +pub const FAN_CLASS_PRE_CONTENT: ::c_uint = 0x0000_0008; + +pub const FAN_UNLIMITED_QUEUE: ::c_uint = 0x0000_0010; +pub const FAN_UNLIMITED_MARKS: ::c_uint = 0x0000_0020; + +pub const FAN_MARK_ADD: ::c_uint = 0x0000_0001; +pub const FAN_MARK_REMOVE: ::c_uint = 0x0000_0002; +pub const FAN_MARK_DONT_FOLLOW: ::c_uint = 0x0000_0004; +pub const FAN_MARK_ONLYDIR: ::c_uint = 0x0000_0008; +pub const FAN_MARK_INODE: ::c_uint = 0x0000_0000; +pub const FAN_MARK_MOUNT: ::c_uint = 0x0000_0010; +// NOTE: FAN_MARK_FILESYSTEM requires Linux Kernel >= 4.20.0 +pub const FAN_MARK_FILESYSTEM: ::c_uint = 0x0000_0100; +pub const FAN_MARK_IGNORED_MASK: ::c_uint = 0x0000_0020; +pub const FAN_MARK_IGNORED_SURV_MODIFY: ::c_uint = 0x0000_0040; +pub const FAN_MARK_FLUSH: ::c_uint = 0x0000_0080; + +pub const FANOTIFY_METADATA_VERSION: u8 = 3; + +pub const FAN_ALLOW: u32 = 0x01; +pub const FAN_DENY: u32 = 0x02; + +pub const FAN_NOFD: ::c_int = -1; + pub const FUTEX_WAIT: ::c_int = 0; pub const FUTEX_WAKE: ::c_int = 1; pub const FUTEX_FD: ::c_int = 2; @@ -3304,6 +3356,7 @@ extern "C" { path: *const ::c_char, mask: u32, ) -> ::c_int; + pub fn fanotify_init(flags: ::c_uint, event_f_flags: ::c_uint) -> ::c_int; } cfg_if! { diff --git a/src/unix/linux_like/linux/musl/mod.rs b/src/unix/linux_like/linux/musl/mod.rs index 73c562c30e..df539ad474 100644 --- a/src/unix/linux_like/linux/musl/mod.rs +++ b/src/unix/linux_like/linux/musl/mod.rs @@ -420,6 +420,16 @@ extern "C" { needle: *const ::c_void, needlelen: ::size_t, ) -> *mut ::c_void; + // Musl targets need the `mask` argument of `fanotify_mark` be specified + // `::c_ulonglong` instead of `u64` or there will be a type mismatch between + // `long long unsigned int` and the expected `uint64_t`. + pub fn fanotify_mark( + fd: ::c_int, + flags: ::c_uint, + mask: ::c_ulonglong, + dirfd: ::c_int, + path: *const ::c_char, + ) -> ::c_int; } cfg_if! { diff --git a/src/unix/linux_like/linux/no_align.rs b/src/unix/linux_like/linux/no_align.rs index a59edcb949..7393d70a09 100644 --- a/src/unix/linux_like/linux/no_align.rs +++ b/src/unix/linux_like/linux/no_align.rs @@ -35,6 +35,17 @@ macro_rules! expand_align { __align: [::c_int; 0], size: [u8; ::__SIZEOF_PTHREAD_CONDATTR_T], } + + pub struct fanotify_event_metadata { + __align: [::c_long; 0], + pub event_len: __u32, + pub vers: __u8, + pub reserved: __u8, + pub metadata_len: __u16, + pub mask: __u64, + pub fd: ::c_int, + pub pid: ::c_int, + } } s_no_extra_traits! 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