os.shell

src/codegen_x86_64.rs

@@ -6,7 +6,6 @@ use crate::{
 };
 
 pub struct Var {
-    // pub var_type: String,
     pub stack_offset: usize,
 }
 
@@ -105,7 +104,7 @@ section .text
 "
         );
 
-        for name in &["malloc", "realloc", "free", "system", "gethostbyname"] {
+        for name in &["malloc", "realloc", "free", "gethostbyname"] {
             emit!(&mut self.output, "extern {}", name);
             emit!(&mut self.output, "c.{} equ {}", name, name);
         }
@@ -156,6 +155,12 @@ _builtin_syscall:
     mov r9,  [rsp+8]
     syscall
     ret
+
+section .text._builtin_environ
+_builtin_environ:
+    extern environ
+    mov rax, [rel environ]
+    ret
 "
         );
         Ok(())
@@ -303,7 +308,7 @@ _builtin_syscall:
                 emit!(&mut self.output, "    jmp {}", env.loop_begin_label);
             }
             Stmt::Extern(name) => {
-                emit!(&mut self.output, "    extern {}", name.lexeme);
+                emit!(&mut self.output, "extern {}", name.lexeme);
             }
         }
         Ok(())

src/parser.rs

@@ -103,6 +103,9 @@ impl Parser {
             if self.match_token(&[TokenType::KeywordFunc]) {
                 return self.func_declaration();
             }
+            if self.match_token(&[TokenType::KeywordExtern]) {
+                return self.extern_declaration();
+            }
             return error!(
                 self.peek().loc,
                 "statements not allowed outside function body"
@@ -175,6 +178,12 @@ impl Parser {
         })
     }
 
+    fn extern_declaration(&mut self) -> Result<Stmt, ZernError> {
+        Ok(Stmt::Extern(
+            self.consume(TokenType::Identifier, "expected extern name")?,
+        ))
+    }
+
     fn block(&mut self) -> Result<Stmt, ZernError> {
         self.consume(TokenType::Indent, "expected an indent")?;
 
@@ -199,10 +208,6 @@ impl Parser {
             Ok(Stmt::Break)
         } else if self.match_token(&[TokenType::KeywordContinue]) {
             Ok(Stmt::Continue)
-        } else if self.match_token(&[TokenType::KeywordExtern]) {
-            Ok(Stmt::Extern(
-                self.consume(TokenType::Identifier, "expected extern name")?,
-            ))
         } else {
             Ok(Stmt::Expression(self.expression()?))
         }

src/std.zr

@@ -430,6 +430,27 @@ func os.time[] : I64
     mem.free(tv)
     return seconds * 1000 + microseconds / 1000
 
+// voodoo magic
+func os.shell[command: String] : I64
+    let pid: I64 = _builtin_syscall(57) // fork
+    if pid == 0
+        let argv: Array = ["sh", "-c", command, 0]
+        _builtin_syscall(59, "/bin/sh", mem.read64(argv), _builtin_environ()) // execve
+        _builtin_syscall(60, 1) // exit
+    else
+        let status: Ptr = mem.alloc(4)
+        let wp: I64 = _builtin_syscall(61, pid, status, 0, 0) // waitpid
+        if wp == -1
+            mem.free(status)
+            return -1
+        let st: I64 = mem.read32(status)
+        mem.free(status)
+        
+        if (st & 0x7f) == 0
+            return (st >> 8) & 0xff
+        else
+            return -(st & 0x7f)
+
 func os.listdir[path: String] : Array
     let fd: I64 = _builtin_syscall(2, path, 0, 0) // open
     if fd < 0