From 3ecd835f58f9c839b10429127ca9cc00ca4d525f Mon Sep 17 00:00:00 2001
From: ridiculousfish <rf@fishshell.com>
Date: Sun, 21 Jan 2024 11:54:26 -0800
Subject: [PATCH] Clean up some stale comments and restore libc usage in
 flog_safe

flog_safe should be explicitly async-signal-safe functions; let's avoid
nix in that module for this reason.
---
 src/common.rs              | 2 +-
 src/fork_exec/flog_safe.rs | 4 +++-
 src/history/file.rs        | 1 -
 src/reader.rs              | 2 +-
 4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/common.rs b/src/common.rs
index 433508ed4b1b..9b4c55d4c87f 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -1468,7 +1468,7 @@ fn can_be_encoded(wc: char) -> bool {
 }
 
 /// Call read, blocking and repeating on EINTR. Exits on EAGAIN.
-/// \return the number of bytes read, or 0 on EOF. On EAGAIN, returns -1 if nothing was read.
+/// \return the number of bytes read, or 0 on EOF, or an error.
 pub fn read_blocked(fd: RawFd, buf: &mut [u8]) -> nix::Result<usize> {
     loop {
         let res = nix::unistd::read(fd, buf);
diff --git a/src/fork_exec/flog_safe.rs b/src/fork_exec/flog_safe.rs
index 164db4f16344..d1c0a922b013 100644
--- a/src/fork_exec/flog_safe.rs
+++ b/src/fork_exec/flog_safe.rs
@@ -84,7 +84,9 @@ pub fn flog_impl_async_safe(fd: i32, s: impl FloggableDisplayAsyncSafe) {
     let bytes: &[u8] = s.to_flog_str_async_safe(&mut storage);
     // Note we deliberately do not retry on signals, etc.
     // This is used to report error messages after fork() in the child process.
-    let _ = nix::unistd::write(fd, bytes);
+    unsafe {
+        let _ = libc::write(fd, bytes.as_ptr() as *const libc::c_void, bytes.len());
+    }
 }
 
 /// Variant of FLOG which is async-safe to use after fork().
diff --git a/src/history/file.rs b/src/history/file.rs
index 887ea92ea1df..6abbf6ff2d06 100644
--- a/src/history/file.rs
+++ b/src/history/file.rs
@@ -228,7 +228,6 @@ fn should_mmap() -> bool {
 }
 
 /// Read from `fd` to fill `dest`, zeroing any unused space.
-// Return true on success, false on failure.
 fn read_from_fd(fd: RawFd, mut dest: &mut [u8]) -> nix::Result<()> {
     while !dest.is_empty() {
         match nix::unistd::read(fd, dest) {
diff --git a/src/reader.rs b/src/reader.rs
index ad3a46d380f3..85bf99d1734c 100644
--- a/src/reader.rs
+++ b/src/reader.rs
@@ -684,7 +684,7 @@ fn read_ni(parser: &Parser, fd: RawFd, io: &IoChain) -> i32 {
         return 1;
     }
 
-    // Read all data into a std::string.
+    // Read all data into a vec.
     let mut fd_contents = Vec::with_capacity(usize::try_from(buf.st_size).unwrap());
     loop {
         let mut buff = [0_u8; 4096];