Add missing utmpx apis for linux musl

Close #4322

Also add a deprecation warning, because those functions are only implemented as stubs inside musl.

Signed-off-by: Etienne Cordonnier <ecordonnier@snap.com>

Author: Ecordonnier

libc-test/semver/linux-musl.txt

@@ -1,3 +1,4 @@
+ACCOUNTING
 AF_IB
 AF_MPLS
 AF_XDP
@@ -37,6 +38,9 @@ RWF_HIPRI
 RWF_NOWAIT
 RWF_SYNC
 USER_PROCESS
+UT_HOSTSIZE
+UT_LINESIZE
+UT_NAMESIZE
 _CS_V6_ENV
 _CS_V7_ENV
 adjtimex
@@ -82,3 +86,4 @@ reallocarray
 setutxent
 tcp_info
 timex
+utmpxname

src/unix/linux_like/linux/musl/mod.rs

@@ -656,7 +656,7 @@ pub const INIT_PROCESS: c_short = 5;
 pub const LOGIN_PROCESS: c_short = 6;
 pub const USER_PROCESS: c_short = 7;
 pub const DEAD_PROCESS: c_short = 8;
-// musl does not define ACCOUNTING
+pub const ACCOUNTING: c_short = 9;
 
 pub const SFD_CLOEXEC: c_int = 0x080000;
 
@@ -888,6 +888,10 @@ pub const _CS_V7_ENV: c_int = 1149;
 
 pub const CLONE_NEWTIME: c_int = 0x80;
 
+pub const UT_HOSTSIZE: usize = 256;
+pub const UT_LINESIZE: usize = 32;
+pub const UT_NAMESIZE: usize = 32;
+
 cfg_if! {
     if #[cfg(target_arch = "s390x")] {
         pub const POSIX_FADV_DONTNEED: c_int = 6;
@@ -898,6 +902,18 @@ cfg_if! {
     }
 }
 
+macro_rules! deprecated_utmpx {
+    ($( $vis:vis fn $fn:ident $args:tt $(-> $ret:ty)?; )*) => {
+        $(
+            #[deprecated(
+                since = "0.2.172",
+                note = "musl provides `utmp` as stubs and an alternative should be preferred; see https://wiki.musl-libc.org/faq.html"
+            )]
+            $vis fn $fn $args $(-> $ret)?;
+        )*
+    };
+}
+
 extern "C" {
     pub fn sendmmsg(
         sockfd: c_int,
@@ -984,12 +1000,15 @@ extern "C" {
         fd: c_int,
     ) -> c_int;
 
-    pub fn getutxent() -> *mut utmpx;
-    pub fn getutxid(ut: *const utmpx) -> *mut utmpx;
-    pub fn getutxline(ut: *const utmpx) -> *mut utmpx;
-    pub fn pututxline(ut: *const utmpx) -> *mut utmpx;
-    pub fn setutxent();
-    pub fn endutxent();
+    deprecated_utmpx! {
+        pub fn getutxent() -> *mut utmpx;
+        pub fn getutxid(ut: *const utmpx) -> *mut utmpx;
+        pub fn getutxline(ut: *const utmpx) -> *mut utmpx;
+        pub fn pututxline(ut: *const utmpx) -> *mut utmpx;
+        pub fn setutxent();
+        pub fn endutxent();
+        pub fn utmpxname(file: *const c_char) -> c_int;
+    }
 }
 
 // Alias <foo> to <foo>64 to mimic glibc's LFS64 support