Retrieve envp, call main

include/cia_definitions.h

@@ -1,8 +1,9 @@
 
 #pragma once
 
-// Pre-C23 keyword macros
+// Pre-C23 keyword macros and stddef
 #define static_assert _Static_assert
+#define NULL ((void *)0)
 
 // Platform macros
 #define CIA_LINUX 1

src/linux/crt_entry.asm

@@ -22,17 +22,26 @@ _start:
     mov r9, rdx
     ;; Get argc and argv from the stack
     pop rsi
-    mov rdx, qword [rsp]
+    mov rdx, rsp
     ;; Align stack to 16, push junk and stack ptr
     and rsp, ~0xf
     push rax
     push rsp
-    ;; Push fini and init sections
+    ;; Load fini and init initializers as function parameters
+    %ifdef CIA_SHARED
         mov rcx, __libc_global_init wrt ..got
         mov r8, __libc_global_fini wrt ..got
+    %else
+        mov rcx, __libc_global_init
+        mov r8, __libc_global_fini
+    %endif
     mov rdi, main
     ;; Call start main
+    %ifdef CIA_SHARED
         call __libc_start_main wrt ..plt
+    %else
+        call __libc_start_main
+    %endif
     ;; No idea why halt it, I guess that's a funny
     ;; way to crash your application if the function we called
     ;; returns instead of calling the exit syscall

src/linux/entry.c

@@ -1,6 +1,6 @@
 
 
-int __stack_chk_fial() {
+int __stack_chk_fail() {
     // TODO: implement proper stack protector support
     return 0;
 }
@@ -10,10 +10,15 @@ void __libc_start_main(
     int argc, char **argv,
     int (*init)(int, char**, char**),
     void (*fini)(void),
-    void (*rtld_fini)(void),
+    void (*runtime_ld_fini)(void),
     void *stack_end
 ) {
-    static char string[] = "Hello, world!\n";
-    syscall_write(STDOUT_FILENO, string, sizeof string);
+    char **envp = argv + (argc + 1);
+    init(argc, argv, envp);
+    main(argc, argv, envp);
+    fini();
+    if(runtime_ld_fini != NULL) {
+        runtime_ld_fini();
+    }
     syscall_exit(0);
 }

test.sh

@@ -3,6 +3,6 @@
 if [ "$1" != "-shared" ]; then
     clang -static -nostdlib tests/empty.c lib/ciabatta.a -Iinclude
 else
-    clang -fPIE tests/empty.c -c -o tests/empty.o
+    clang -g -fno-stack-protector -fPIE tests/empty.c -c -o tests/empty.o
     ld -no-pie -nostdlib lib/entry.o tests/empty.o lib/ciabatta.so lib/ctors.o -Iinclude
 fi

tests/empty.c

@@ -1,4 +1,22 @@
 
-int main() {
+#include <cia_definitions.h>
+
+#define STDOUT_FILENO 1
+#define SYS_write 1
+
+static __inline i64 __syscall3(i64 n, i64 a1, i64 a2, i64 a3) {
+    i64 ret;
+    __asm__ __volatile__ ("syscall" : "=a"(ret) : "a"(n), "D"(a1), "S"(a2),
+                          "d"(a3) : "rcx", "r11", "memory");
+    return ret;
+}
+
+static inline i64 syscall_write(u32 fd, char const *buf, u64 count) {
+    return __syscall3(SYS_write, (i64)fd, (i64)buf, (u64)count);
+}
+
+char string[] = "Hello, world!\n";
+int main(int argc, char **argv, char **envp) {
+    syscall_write(STDOUT_FILENO, string, sizeof string);
     return 0;
 }