From 53e1718a6801fc277b54b02ceeb4b659df313b64 Mon Sep 17 00:00:00 2001
From: xtqqczze <45661989+xtqqczze@users.noreply.github.com>
Date: Thu, 26 Feb 2026 21:43:23 +0000
Subject: [PATCH] fix: pointer and signal handler casts
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- avoid UB from `usize` → pointer cast
- use correct type for `sa_sigaction`

Closes #12488
---
 crates/printf/src/tests.rs | 6 ++++--
 src/signal.rs              | 8 ++++----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/crates/printf/src/tests.rs b/crates/printf/src/tests.rs
index 5d1e41bd9..2d503b781 100644
--- a/crates/printf/src/tests.rs
+++ b/crates/printf/src/tests.rs
@@ -400,8 +400,10 @@ fn test_char() {
 
 #[test]
 fn test_ptr() {
-    assert_fmt!("%p", core::ptr::null::<u8>() => "0");
-    assert_fmt!("%p", 0xDEADBEEF_usize as *const u8 => "0xdeadbeef");
+    assert_fmt!("%p", core::ptr::null::<()>() => "0");
+
+    let tmp = core::ptr::without_provenance::<()>(0xDEADBEEF);
+    assert_fmt!("%p", tmp => "0xdeadbeef");
 }
 
 #[test]
diff --git a/src/signal.rs b/src/signal.rs
index 4837ec432..8e40fa10c 100644
--- a/src/signal.rs
+++ b/src/signal.rs
@@ -157,7 +157,7 @@ fn sigaction(sig: i32, act: &libc::sigaction, oact: *mut libc::sigaction) -> lib
 }
 
 fn set_interactive_handlers() {
-    let signal_handler: usize = fish_signal_handler as *const () as usize;
+    let signal_handler: usize = fish_signal_handler as *const () as libc::sighandler_t;
     let mut act: libc::sigaction = unsafe { std::mem::zeroed() };
     let mut oact: libc::sigaction = unsafe { std::mem::zeroed() };
     act.sa_flags = 0;
@@ -221,12 +221,12 @@ pub fn signal_set_handlers(interactive: bool) {
     sigaction(libc::SIGQUIT, &act, nullptr);
 
     // Apply our SIGINT handler.
-    act.sa_sigaction = fish_signal_handler as *const () as usize;
+    act.sa_sigaction = fish_signal_handler as *const () as libc::sighandler_t;
     act.sa_flags = libc::SA_SIGINFO;
     sigaction(libc::SIGINT, &act, nullptr);
 
     // Whether or not we're interactive we want SIGCHLD to not interrupt restartable syscalls.
-    act.sa_sigaction = fish_signal_handler as *const () as usize;
+    act.sa_sigaction = fish_signal_handler as *const () as libc::sighandler_t;
     act.sa_flags = libc::SA_SIGINFO | libc::SA_RESTART;
     if sigaction(libc::SIGCHLD, &act, nullptr) != 0 {
         perror("sigaction");
@@ -279,7 +279,7 @@ pub fn signal_handle(sig: Signal) {
     act.sa_flags = 0;
     unsafe { libc::sigemptyset(&mut act.sa_mask) };
     act.sa_flags = libc::SA_SIGINFO;
-    act.sa_sigaction = fish_signal_handler as *const () as usize;
+    act.sa_sigaction = fish_signal_handler as *const () as libc::sighandler_t;
     sigaction(sig, &act, std::ptr::null_mut());
 }