fix argv handling

libuwuc/src/start.rs

@@ -4,7 +4,9 @@ use crate::utils::SharedThinCstr;
 
 /// The entrypoint of the program.
 /// This is called by a bit of assembly handling architecture-specific _start.
-pub(crate) unsafe extern "C" fn start(argc: u64, argv: *const *const c_char, rsp: u64) -> ! {
+pub(crate) unsafe extern "C" fn start(rsp: u64) -> ! {
+    let argc = (rsp as *const u64).read();
+    let argv = (rsp + 8) as *const *const c_char;
     let envp = (8 + 8 * argc + rsp + 8) as *mut Option<SharedThinCstr<'static>>;
 
     crate::env::init(envp);

libuwuc/src/sys/x86_64/start.rs

@@ -8,9 +8,7 @@ core::arch::global_asm!(
     "mov rbp, 0",
     // We're off to a good start already.
     // Pass the variables to the start function arguments.
-    "mov rdi, [rsp]",       // &argc = rsp
+    "mov rdi, rsp",
-    "mov rsi, [rsp+8]",     // &argv = rsp+8
-    "mov rdx, rsp",
 
     // The stack will be 16-byte aligned at process entry already.
     // So we're good to go!

rawc/src/stdio.rs

@@ -46,7 +46,7 @@ pub unsafe extern "C" fn printf(format: *const u8, mut args: ...) -> c_int {
 
 
 #[no_mangle]
-pub unsafe extern "C" fn __fprintf_chk(file: &FileStream, _flag: c_int, format: *const u8, mut args: ...) -> c_int {
+pub unsafe extern "C" fn __fprintf_chk(_flag: c_int, file: &FileStream, format: *const u8, mut args: ...) -> c_int {
     let mut sink = WriteCounter(file, 0);
 
     let result = libuwuc::fmt::printf::printf_generic(

shell.nix

@@ -7,5 +7,6 @@
     export PATH=$PATH:''${CARGO_HOME:-~/.cargo}/bin
   '';
   packages = (with pkgs; [
+    gef
   ]);
 }

test_c.sh

@@ -21,13 +21,18 @@ for test in tests/c/*; do
         exit 1
     fi
 
+    printf "test $name "
+
     OUTPUT=$("$test_dir/$name")
     code="$?"
     if [ "$code" -ne "0" ]; then
+        echo -e "\e[31mFAIL\e[0m"
         echo "error: test failed with code $code: $test, running $test_dir/$name"
         echo "------ output:"
         echo "$OUTPUT"
         echo "-----"
+    else
+        echo -e "\e[32mPASS\e[0m"
     fi
 done
 

tests/c/argv.c

@@ -0,0 +1,9 @@
+#include<stdio.h>
+
+int main(int argc, char* argv[]) {
+    char *self = argv[0];
+    char first = self[0];
+    if (first != '/') {
+        return 1;
+    }
+}

tests/c/malloc.c

@@ -0,0 +1,8 @@
+#include<stdlib.h>
+
+int main(void) {
+    char *alloc = (char*) malloc(10);
+    *alloc = 1;
+    *(alloc + 9) = 2;
+    free(alloc);
+}