Merge pull request #52 from wasmerio/fix/emscripten-env

Fix support for env vars (put, set, unset)

build/emtests.rs

@@ -11,7 +11,7 @@ use std::process::Command;
 static BANNER: &str = "// Rust test file autogenerated with cargo build (build/emtests.rs).
 // Please do NOT modify it by hand, as it will be reseted on next build.\n";
 
-const TESTS: [&str; 2] = ["emtests/puts.c", "emtests/printf.c"];
+const TESTS: [&str; 3] = ["emtests/env.c", "emtests/puts.c", "emtests/printf.c"];
 
 pub fn compile(file: &str) -> String {
     let mut output_path = PathBuf::from(file);

emtests/env.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <stdlib.h>
+int main()
+{   
+    printf("INIT\n");
+    const char* UNEXISTENT_ENVVAR = getenv("UNEXISTENT_ENVVAR");
+    printf("UNEXISTENT_ENVVAR = %s\n",(UNEXISTENT_ENVVAR!=NULL)? UNEXISTENT_ENVVAR : "[NULL]");
+    printf("Setting UNEXISTENT_ENVVAR=PUTENV (via putenv)\n");
+    putenv("UNEXISTENT_ENVVAR=PUTENV");
+    UNEXISTENT_ENVVAR = getenv("UNEXISTENT_ENVVAR");
+    printf("UNEXISTENT_ENVVAR = %s\n",(UNEXISTENT_ENVVAR!=NULL)? UNEXISTENT_ENVVAR : "[NULL]");
+    printf("Setting UNEXISTENT_ENVVAR=SETENV (via setenv, overwrite)\n");
+    setenv("UNEXISTENT_ENVVAR", "SETENV", 1);
+    UNEXISTENT_ENVVAR = getenv("UNEXISTENT_ENVVAR");
+    printf("UNEXISTENT_ENVVAR = %s\n",(UNEXISTENT_ENVVAR!=NULL)? UNEXISTENT_ENVVAR : "[NULL]");
+    printf("Setting UNEXISTENT_ENVVAR=SETENV_NEW (via setenv, NO overwrite)\n");
+    setenv("UNEXISTENT_ENVVAR", "SETENV_NEW", 0);
+    UNEXISTENT_ENVVAR = getenv("UNEXISTENT_ENVVAR");
+    printf("UNEXISTENT_ENVVAR = %s\n",(UNEXISTENT_ENVVAR!=NULL)? UNEXISTENT_ENVVAR : "[NULL]");
+    printf("Unsetting UNEXISTENT_ENVVAR\n");
+    unsetenv("UNEXISTENT_ENVVAR");
+    UNEXISTENT_ENVVAR = getenv("UNEXISTENT_ENVVAR");
+    printf("UNEXISTENT_ENVVAR = %s\n",(UNEXISTENT_ENVVAR!=NULL)? UNEXISTENT_ENVVAR : "[NULL]");
+    printf("END\n");
+}

emtests/env.output

@@ -0,0 +1,11 @@
+INIT
+UNEXISTENT_ENVVAR = [NULL]
+Setting UNEXISTENT_ENVVAR=PUTENV (via putenv)
+UNEXISTENT_ENVVAR = PUTENV
+Setting UNEXISTENT_ENVVAR=SETENV (via setenv, overwrite)
+UNEXISTENT_ENVVAR = SETENV
+Setting UNEXISTENT_ENVVAR=SETENV_NEW (via setenv, NO overwrite)
+UNEXISTENT_ENVVAR = SETENV
+Unsetting UNEXISTENT_ENVVAR
+UNEXISTENT_ENVVAR = [NULL]
+END

src/apis/emscripten/README.md

@@ -26,9 +26,21 @@
 
 ###### ENVIRONMENT
 
-- **\_getenv**     [:top:](#host-apis)
+- **\_getenv** ✅     [:top:](#host-apis)
   ```rust
-
+  fn _getenv(name: c_int, instance: &mut Instance)
+  ```
+- **\_putenv** ✅     [:top:](#host-apis)
+  ```rust
+  fn _putenv(name: c_int, instance: &mut Instance)
+  ```
+- **\_setenv** ✅     [:top:](#host-apis)
+  ```rust
+  fn _setenv(name: c_int, value: c_int, overwrite: c_int, instance: &mut Instance
+  ```
+- **\_unsetenv** ✅     [:top:](#host-apis)
+  ```rust
+  fn _unsetenv(name: c_int, instance: &mut Instance)
   ```
 
 ###### THREAD
@@ -44,10 +56,6 @@
 - **\_pthread_setspecific**     [:top:](#host-apis)
   ```rust
 
-  ```
-- **\_unsetenv**     [:top:](#host-apis)
-  ```rust
-
   ```
 - **\_\_\_lock**     [:top:](#host-apis)
   ```rust

src/apis/emscripten/env.rs

@@ -1,11 +1,14 @@
 use super::super::host;
 /// NOTE: These syscalls only support wasm_32 for now because they take u32 offset
-use libc::{c_int, c_long, getenv, getgrnam as libc_getgrnam, getpwnam as libc_getpwnam, sysconf};
+use libc::{
+    c_int, c_long, getenv, getgrnam as libc_getgrnam, getpwnam as libc_getpwnam, putenv, setenv,
+    sysconf, unsetenv,
+};
 use std::ffi::CStr;
 use std::mem;
 use std::os::raw::c_char;
 
-use super::utils::{copy_cstr_into_wasm, copy_terminated_array_of_cstrs};
+use super::utils::{allocate_on_stack, copy_cstr_into_wasm, copy_terminated_array_of_cstrs};
 use crate::webassembly::Instance;
 
 // #[no_mangle]
@@ -25,6 +28,41 @@ pub extern "C" fn _getenv(name: c_int, instance: &mut Instance) -> u32 {
     unsafe { copy_cstr_into_wasm(instance, c_str) }
 }
 
+/// emscripten: _setenv // (name: *const char, name: *const value, overwrite: int);
+pub extern "C" fn _setenv(name: c_int, value: c_int, overwrite: c_int, instance: &mut Instance) {
+    debug!("emscripten::_setenv");
+
+    let name_addr = instance.memory_offset_addr(0, name as usize) as *const c_char;
+    let value_addr = instance.memory_offset_addr(0, value as usize) as *const c_char;
+
+    debug!("=> name({:?})", unsafe { CStr::from_ptr(name_addr) });
+    debug!("=> value({:?})", unsafe { CStr::from_ptr(value_addr) });
+
+    unsafe { setenv(name_addr, value_addr, overwrite) };
+}
+
+/// emscripten: _putenv // (name: *const char);
+pub extern "C" fn _putenv(name: c_int, instance: &mut Instance) {
+    debug!("emscripten::_putenv");
+
+    let name_addr = instance.memory_offset_addr(0, name as usize) as *const c_char;
+
+    debug!("=> name({:?})", unsafe { CStr::from_ptr(name_addr) });
+
+    unsafe { putenv(name_addr as _) };
+}
+
+/// emscripten: _unsetenv // (name: *const char);
+pub extern "C" fn _unsetenv(name: c_int, instance: &mut Instance) {
+    debug!("emscripten::_unsetenv");
+
+    let name_addr = instance.memory_offset_addr(0, name as usize) as *const c_char;
+
+    debug!("=> name({:?})", unsafe { CStr::from_ptr(name_addr) });
+
+    unsafe { unsetenv(name_addr) };
+}
+
 pub extern "C" fn _getpwnam(name_ptr: c_int, instance: &mut Instance) -> c_int {
     debug!("emscripten::_getpwnam {}", name_ptr);
 
@@ -104,8 +142,26 @@ pub extern "C" fn _getpagesize() -> u32 {
     16384
 }
 
-pub extern "C" fn ___build_environment(environ: c_int) {
+pub extern "C" fn ___build_environment(environ: c_int, instance: &mut Instance) {
     debug!("emscripten::___build_environment {}", environ);
+    const MAX_ENV_VALUES: u32 = 64;
+    const TOTAL_ENV_SIZE: u32 = 1024;
+    let mut environment = instance.memory_offset_addr(0, environ as _) as *mut c_int;
+    unsafe {
+        let (pool_offset, pool_slice): (u32, &mut [u8]) =
+            allocate_on_stack(TOTAL_ENV_SIZE as u32, instance);
+        let (env_offset, env_slice): (u32, &mut [u8]) =
+            allocate_on_stack((MAX_ENV_VALUES * 4) as u32, instance);
+        let mut env_ptr = instance.memory_offset_addr(0, env_offset as _) as *mut c_int;
+        let mut pool_ptr = instance.memory_offset_addr(0, pool_offset as _) as *mut c_int;
+        *env_ptr = pool_offset as i32;
+        *environment = env_offset as i32;
+
+        // *env_ptr = 0;
+    };
+    // unsafe {
+    //     *env_ptr = 0;
+    // };
 }
 
 pub extern "C" fn _sysconf(name: c_int, _instance: &mut Instance) -> c_long {

src/apis/emscripten/mod.rs

@@ -114,6 +114,9 @@ pub fn generate_emscripten_env<'a, 'b>() -> ImportObject<&'a str, &'b str> {
     import_object.set("env", "___wait", ImportValue::Func(lock::___wait as _));
     // Env
     import_object.set("env", "_getenv", ImportValue::Func(env::_getenv as _));
+    import_object.set("env", "_setenv", ImportValue::Func(env::_setenv as _));
+    import_object.set("env", "_putenv", ImportValue::Func(env::_putenv as _));
+    import_object.set("env", "_unsetenv", ImportValue::Func(env::_unsetenv as _));
     import_object.set("env", "_getpwnam", ImportValue::Func(env::_getpwnam as _));
     import_object.set("env", "_getgrnam", ImportValue::Func(env::_getgrnam as _));
     import_object.set(

src/emtests/env.rs

@@ -0,0 +1,9 @@
+#[test]
+fn test_env() {
+    assert_emscripten_output!(
+        "../../emtests/env.wasm",
+        "env",
+        vec![],
+        "../../emtests/env.output"
+    );
+}

src/emtests/mod.rs

@@ -4,5 +4,6 @@
 // The _common module is not autogenerated, as it provides common macros for the emtests
 #[macro_use]
 mod _common;
+mod env;
 mod printf;
 mod puts;