fix(ld): make environ preemptable

Signed-off-by: Anhad Singh <andypython@protonmail.com>

dynlst.txt

@@ -1,4 +1,6 @@
 {
+environ;
+
 stdin;
 stdout;
 stderr;

src/ld_so/linker.rs

@@ -563,7 +563,9 @@ impl Linker {
 
     pub fn fini(&self) {
         for obj in self.objects.values() {
-            obj.run_fini();
+            unsafe {
+                obj.run_fini();
+            }
         }
     }
 

src/ld_so/start.rs

@@ -1,6 +1,6 @@
 // Start code adapted from https://gitlab.redox-os.org/redox-os/relibc/blob/master/src/start.rs
 
-use core::slice;
+use core::{slice, str::FromStr};
 
 use alloc::{
     borrow::ToOwned,
@@ -9,6 +9,7 @@ use alloc::{
     string::{String, ToString},
     vec::Vec,
 };
+use log::LevelFilter;
 use object::{
     NativeEndian,
     elf::{self, PT_DYNAMIC, PT_PHDR},
@@ -28,7 +29,7 @@ use crate::{
         },
         linker::{DebugFlags, Me},
     },
-    platform::{auxv_iter, get_auxvs, types::c_char},
+    platform::{auxv_iter, get_auxvs, logger::RELIBC_LOG_ENV_VAR, types::c_char},
     start::Stack,
     sync::mutex::Mutex,
 };
@@ -406,9 +407,10 @@ fn stage2(
                 .collect::<Vec<_>>(),
         );
 
-        crate::platform::environ = crate::platform::OUR_ENVIRON.unsafe_mut().as_mut_ptr();
-
-        if let Err(_) = crate::platform::logger::init() {
+        if let Some(env) = envs.get(RELIBC_LOG_ENV_VAR.to_str().unwrap())
+            && let Ok(level) = LevelFilter::from_str(env)
+            && let Err(_) = crate::platform::logger::init(level)
+        {
             log::error!("Logger has already been initialised");
         }
     }

src/platform/logger.rs

@@ -1,28 +1,26 @@
-use core::{fmt, str::FromStr};
+use core::fmt;
 
 use crate::{c_str::CStr, io::prelude::*, sync::Mutex};
 
 use alloc::string::{String, ToString};
-use log::{Metadata, Record, SetLoggerError};
+use log::{LevelFilter, Metadata, Record, SetLoggerError};
 
 const DEFAULT_LOG_LEVEL: log::LevelFilter = log::LevelFilter::Info;
 
-pub unsafe fn init() -> Result<(), SetLoggerError> {
+pub const RELIBC_LOG_ENV_VAR: &'static core::ffi::CStr = c"RELIBC_LOG_LEVEL";
+
+pub unsafe fn init(level: LevelFilter) -> Result<(), SetLoggerError> {
     let mut logger = RedoxLogger::new();
-    let log_env = c"RELIBC_LOG_LEVEL".as_ptr();
     #[cfg(feature = "no_trace")]
     let mut trace_warn = false;
     unsafe {
-        if let Some(env) = CStr::from_nullable_ptr(crate::header::stdlib::getenv(log_env))
-            && let Ok(level) = log::LevelFilter::from_str(env.to_str().unwrap_or(""))
-        {
-            #[cfg(feature = "no_trace")]
-            if level == log::LevelFilter::Trace {
-                trace_warn = true;
-            }
-
-            logger = logger.with_output(OutputBuilder::stderr().with_filter(level).build());
+        #[cfg(feature = "no_trace")]
+        if level == log::LevelFilter::Trace {
+            trace_warn = true;
         }
+
+        logger = logger.with_output(OutputBuilder::stderr().with_filter(level).build());
+
         if let Some(name) = CStr::from_nullable_ptr(crate::platform::program_invocation_short_name)
         {
             logger = logger.with_process_name(name.to_str().unwrap_or("").to_string());

src/start.rs

@@ -1,12 +1,13 @@
 //! Startup code.
 
 use alloc::vec::Vec;
-use core::{intrinsics, ptr};
+use core::{intrinsics, ptr, str::FromStr};
 
 use crate::{
+    c_str::CStr,
     header::{libgen, stdio, stdlib},
     ld_so::{self},
-    platform::{self, Pal, Sys, get_auxvs, types::*},
+    platform::{self, Pal, Sys, get_auxvs, logger::RELIBC_LOG_ENV_VAR, types::*},
 };
 
 #[repr(C)]
@@ -221,8 +222,12 @@ pub unsafe extern "C" fn relibc_start_v1(
         unsafe { crate::platform::init(auxvs) };
         init_array();
     }
-    unsafe {
-        if let Err(_) = crate::platform::logger::init()
+
+    if let Some(env) = unsafe {
+        CStr::from_nullable_ptr(crate::header::stdlib::getenv(RELIBC_LOG_ENV_VAR.as_ptr()))
+    } && let Ok(level) = log::LevelFilter::from_str(env.to_str().unwrap_or(""))
+    {
+        if let Err(_) = unsafe { crate::platform::logger::init(level) }
             && !is_dynamically_linked
         {
             log::error!("Logger has already been initialised");