Auto merge of #124636 - tbu-:pr_env_unsafe, r=petrochenkov

Make `std::env::{set_var, remove_var}` unsafe in edition 2024

Allow calling these functions without `unsafe` blocks in editions up until 2021, but don't trigger the `unused_unsafe` lint for `unsafe` blocks containing these functions.

Fixes #27970.
Fixes #90308.
CC #124866.

11 files changed, 29 insertions, 33 deletions

diff --git a/library/std/src/sys/pal/hermit/os.rs b/library/std/src/sys/pal/hermit/os.rs
index cc678123831..91247d30462 100644
--- a/library/std/src/sys/pal/hermit/os.rs
+++ b/library/std/src/sys/pal/hermit/os.rs
@@ -172,18 +172,14 @@ pub fn getenv(k: &OsStr) -> Option<OsString> {
     unsafe { ENV.as_ref().unwrap().lock().unwrap().get_mut(k).cloned() }
 }
 
-pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
-    unsafe {
-        let (k, v) = (k.to_owned(), v.to_owned());
-        ENV.as_ref().unwrap().lock().unwrap().insert(k, v);
-    }
+pub unsafe fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
+    let (k, v) = (k.to_owned(), v.to_owned());
+    ENV.as_ref().unwrap().lock().unwrap().insert(k, v);
     Ok(())
 }
 
-pub fn unsetenv(k: &OsStr) -> io::Result<()> {
-    unsafe {
-        ENV.as_ref().unwrap().lock().unwrap().remove(k);
-    }
+pub unsafe fn unsetenv(k: &OsStr) -> io::Result<()> {
+    ENV.as_ref().unwrap().lock().unwrap().remove(k);
     Ok(())
 }
 
diff --git a/library/std/src/sys/pal/sgx/os.rs b/library/std/src/sys/pal/sgx/os.rs
index 86f4c7d3d56..c021300d4ae 100644
--- a/library/std/src/sys/pal/sgx/os.rs
+++ b/library/std/src/sys/pal/sgx/os.rs
@@ -157,13 +157,13 @@ pub fn getenv(k: &OsStr) -> Option<OsString> {
     get_env_store().and_then(|s| s.lock().unwrap().get(k).cloned())
 }
 
-pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
+pub unsafe fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     let (k, v) = (k.to_owned(), v.to_owned());
     create_env_store().lock().unwrap().insert(k, v);
     Ok(())
 }
 
-pub fn unsetenv(k: &OsStr) -> io::Result<()> {
+pub unsafe fn unsetenv(k: &OsStr) -> io::Result<()> {
     if let Some(env) = get_env_store() {
         env.lock().unwrap().remove(k);
     }
diff --git a/library/std/src/sys/pal/solid/os.rs b/library/std/src/sys/pal/solid/os.rs
index ef35d8788a2..ac90aae4ebe 100644
--- a/library/std/src/sys/pal/solid/os.rs
+++ b/library/std/src/sys/pal/solid/os.rs
@@ -191,7 +191,7 @@ pub fn getenv(k: &OsStr) -> Option<OsString> {
     .flatten()
 }
 
-pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
+pub unsafe fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     run_with_cstr(k.as_bytes(), &|k| {
         run_with_cstr(v.as_bytes(), &|v| {
             let _guard = ENV_LOCK.write();
@@ -200,7 +200,7 @@ pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     })
 }
 
-pub fn unsetenv(n: &OsStr) -> io::Result<()> {
+pub unsafe fn unsetenv(n: &OsStr) -> io::Result<()> {
     run_with_cstr(n.as_bytes(), &|nbuf| {
         let _guard = ENV_LOCK.write();
         cvt_env(unsafe { libc::unsetenv(nbuf.as_ptr()) }).map(drop)
diff --git a/library/std/src/sys/pal/teeos/os.rs b/library/std/src/sys/pal/teeos/os.rs
index e54a92f01f8..3be0846a6dd 100644
--- a/library/std/src/sys/pal/teeos/os.rs
+++ b/library/std/src/sys/pal/teeos/os.rs
@@ -109,11 +109,11 @@ pub fn getenv(_: &OsStr) -> Option<OsString> {
     None
 }
 
-pub fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
+pub unsafe fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
     Err(io::Error::new(io::ErrorKind::Unsupported, "cannot set env vars on this platform"))
 }
 
-pub fn unsetenv(_: &OsStr) -> io::Result<()> {
+pub unsafe fn unsetenv(_: &OsStr) -> io::Result<()> {
     Err(io::Error::new(io::ErrorKind::Unsupported, "cannot unset env vars on this platform"))
 }
 
diff --git a/library/std/src/sys/pal/uefi/os.rs b/library/std/src/sys/pal/uefi/os.rs
index 58838c5876e..0b27977df2f 100644
--- a/library/std/src/sys/pal/uefi/os.rs
+++ b/library/std/src/sys/pal/uefi/os.rs
@@ -203,11 +203,11 @@ pub fn getenv(_: &OsStr) -> Option<OsString> {
     None
 }
 
-pub fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
+pub unsafe fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
     Err(io::const_io_error!(io::ErrorKind::Unsupported, "cannot set env vars on this platform"))
 }
 
-pub fn unsetenv(_: &OsStr) -> io::Result<()> {
+pub unsafe fn unsetenv(_: &OsStr) -> io::Result<()> {
     Err(io::const_io_error!(io::ErrorKind::Unsupported, "cannot unset env vars on this platform"))
 }
 
diff --git a/library/std/src/sys/pal/unix/os.rs b/library/std/src/sys/pal/unix/os.rs
index 8afc49f5227..b5c7d30da7b 100644
--- a/library/std/src/sys/pal/unix/os.rs
+++ b/library/std/src/sys/pal/unix/os.rs
@@ -675,19 +675,19 @@ pub fn getenv(k: &OsStr) -> Option<OsString> {
     .flatten()
 }
 
-pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
+pub unsafe fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     run_with_cstr(k.as_bytes(), &|k| {
         run_with_cstr(v.as_bytes(), &|v| {
             let _guard = ENV_LOCK.write();
-            cvt(unsafe { libc::setenv(k.as_ptr(), v.as_ptr(), 1) }).map(drop)
+            cvt(libc::setenv(k.as_ptr(), v.as_ptr(), 1)).map(drop)
         })
     })
 }
 
-pub fn unsetenv(n: &OsStr) -> io::Result<()> {
+pub unsafe fn unsetenv(n: &OsStr) -> io::Result<()> {
     run_with_cstr(n.as_bytes(), &|nbuf| {
         let _guard = ENV_LOCK.write();
-        cvt(unsafe { libc::unsetenv(nbuf.as_ptr()) }).map(drop)
+        cvt(libc::unsetenv(nbuf.as_ptr())).map(drop)
     })
 }
 
diff --git a/library/std/src/sys/pal/unsupported/os.rs b/library/std/src/sys/pal/unsupported/os.rs
index 248b34829f2..3be98898bbe 100644
--- a/library/std/src/sys/pal/unsupported/os.rs
+++ b/library/std/src/sys/pal/unsupported/os.rs
@@ -96,11 +96,11 @@ pub fn getenv(_: &OsStr) -> Option<OsString> {
     None
 }
 
-pub fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
+pub unsafe fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
     Err(io::const_io_error!(io::ErrorKind::Unsupported, "cannot set env vars on this platform"))
 }
 
-pub fn unsetenv(_: &OsStr) -> io::Result<()> {
+pub unsafe fn unsetenv(_: &OsStr) -> io::Result<()> {
     Err(io::const_io_error!(io::ErrorKind::Unsupported, "cannot unset env vars on this platform"))
 }
 
diff --git a/library/std/src/sys/pal/wasi/os.rs b/library/std/src/sys/pal/wasi/os.rs
index ee377b6ef79..e96296997e6 100644
--- a/library/std/src/sys/pal/wasi/os.rs
+++ b/library/std/src/sys/pal/wasi/os.rs
@@ -244,7 +244,7 @@ pub fn getenv(k: &OsStr) -> Option<OsString> {
     .flatten()
 }
 
-pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
+pub unsafe fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     run_with_cstr(k.as_bytes(), &|k| {
         run_with_cstr(v.as_bytes(), &|v| unsafe {
             let _guard = env_write_lock();
@@ -253,7 +253,7 @@ pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     })
 }
 
-pub fn unsetenv(n: &OsStr) -> io::Result<()> {
+pub unsafe fn unsetenv(n: &OsStr) -> io::Result<()> {
     run_with_cstr(n.as_bytes(), &|nbuf| unsafe {
         let _guard = env_write_lock();
         cvt(libc::unsetenv(nbuf.as_ptr())).map(drop)
diff --git a/library/std/src/sys/pal/windows/os.rs b/library/std/src/sys/pal/windows/os.rs
index 64d8b72aed2..483b8b0072c 100644
--- a/library/std/src/sys/pal/windows/os.rs
+++ b/library/std/src/sys/pal/windows/os.rs
@@ -302,16 +302,16 @@ pub fn getenv(k: &OsStr) -> Option<OsString> {
     .ok()
 }
 
-pub fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
+pub unsafe fn setenv(k: &OsStr, v: &OsStr) -> io::Result<()> {
     let k = to_u16s(k)?;
     let v = to_u16s(v)?;
 
-    cvt(unsafe { c::SetEnvironmentVariableW(k.as_ptr(), v.as_ptr()) }).map(drop)
+    cvt(c::SetEnvironmentVariableW(k.as_ptr(), v.as_ptr())).map(drop)
 }
 
-pub fn unsetenv(n: &OsStr) -> io::Result<()> {
+pub unsafe fn unsetenv(n: &OsStr) -> io::Result<()> {
     let v = to_u16s(n)?;
-    cvt(unsafe { c::SetEnvironmentVariableW(v.as_ptr(), ptr::null()) }).map(drop)
+    cvt(c::SetEnvironmentVariableW(v.as_ptr(), ptr::null())).map(drop)
 }
 
 pub fn temp_dir() -> PathBuf {
diff --git a/library/std/src/sys/pal/xous/os.rs b/library/std/src/sys/pal/xous/os.rs
index 8d2eaee8aa6..9be09eed629 100644
--- a/library/std/src/sys/pal/xous/os.rs
+++ b/library/std/src/sys/pal/xous/os.rs
@@ -149,11 +149,11 @@ pub fn getenv(_: &OsStr) -> Option<OsString> {
     None
 }
 
-pub fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
+pub unsafe fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
     Err(io::const_io_error!(io::ErrorKind::Unsupported, "cannot set env vars on this platform"))
 }
 
-pub fn unsetenv(_: &OsStr) -> io::Result<()> {
+pub unsafe fn unsetenv(_: &OsStr) -> io::Result<()> {
     Err(io::const_io_error!(io::ErrorKind::Unsupported, "cannot unset env vars on this platform"))
 }
 
diff --git a/library/std/src/sys/pal/zkvm/os.rs b/library/std/src/sys/pal/zkvm/os.rs
index 759beb2d306..e7d6cd52a25 100644
--- a/library/std/src/sys/pal/zkvm/os.rs
+++ b/library/std/src/sys/pal/zkvm/os.rs
@@ -115,11 +115,11 @@ pub fn getenv(varname: &OsStr) -> Option<OsString> {
     Some(OsString::from_inner(os_str::Buf { inner: u8s.to_vec() }))
 }
 
-pub fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
+pub unsafe fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
     Err(io::const_io_error!(io::ErrorKind::Unsupported, "cannot set env vars on this platform"))
 }
 
-pub fn unsetenv(_: &OsStr) -> io::Result<()> {
+pub unsafe fn unsetenv(_: &OsStr) -> io::Result<()> {
     Err(io::const_io_error!(io::ErrorKind::Unsupported, "cannot unset env vars on this platform"))
 }