From 9fc7438b82cb514f0be910b5bbe2b17872596ea2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C5=8Dshin?= <git@wholezero.org>
Date: Fri, 15 Dec 2023 07:21:48 +0000
Subject: [PATCH] Loader passes executable name as rdx

---
 ape/launch.S                                        | 13 ++++++-------
 ape/loader.c                                        |  6 +++---
 libc/crt/crt.S                                      |  2 ++
 ...executable_name2.c => program_executable_name.c} |  0
 4 files changed, 11 insertions(+), 10 deletions(-)
 rename libc/nexgen32e/{program_executable_name2.c => program_executable_name.c} (100%)

diff --git a/ape/launch.S b/ape/launch.S
index d4d89651a..87489f9f5 100644
--- a/ape/launch.S
+++ b/ape/launch.S
@@ -31,17 +31,16 @@
 //
 //	@param	rdi is passed through as-is
 //	@param	rsi is address of entrypoint (becomes zero)
-//	@param	rdx is stack pointer (becomes zero)
-//	@param	rcx is passed through as-is
+//	@param	rdx is passed through as-is
+//	@param	rcx is stack pointer (becomes r8)
 //	@noreturn
 Launch:
 #ifdef __aarch64__
 
 	mov	x16,x1
-	mov	sp,x2
+	mov	sp,x3
 	mov	x1,0
-	mov	x2,0
-	mov	x3,0
+	mov	x3,x4
 	mov	x4,0
 	mov	x5,0
 	mov	x6,0
@@ -71,6 +70,8 @@ Launch:
 
 #else
 
+	mov	%rcx,%rsp
+	mov	%r8,%rcx
 	xor	%r8d,%r8d
 	xor	%r9d,%r9d
 	xor	%r10d,%r10d
@@ -79,8 +80,6 @@ Launch:
 	xor	%r13d,%r13d
 	xor	%r14d,%r14d
 	xor	%r15d,%r15d
-	mov	%rdx,%rsp
-	xor	%edx,%edx
 	push	%rsi
 	xor	%esi,%esi
 	xor	%ebp,%ebp
diff --git a/ape/loader.c b/ape/loader.c
index 5af2028d1..87369cc42 100644
--- a/ape/loader.c
+++ b/ape/loader.c
@@ -645,8 +645,8 @@ static char *Commandv(struct PathSearcher *ps, int os, const char *name,
 }
 
 __attribute__((__noreturn__)) static void Spawn(int os, const char *exe,
-                                                const char *path, int fd,
-                                                long *sp, unsigned long pagesz,
+                                                char *path, int fd, long *sp,
+                                                unsigned long pagesz,
                                                 struct ElfEhdr *e,
                                                 struct ElfPhdr *p) {
   long rc;
@@ -807,7 +807,7 @@ __attribute__((__noreturn__)) static void Spawn(int os, const char *exe,
 }
 
 static const char *TryElf(struct ApeLoader *M, union ElfEhdrBuf *ebuf,
-                          const char *exe, const char *path, int fd, long *sp,
+                          const char *exe, char *path, int fd, long *sp,
                           long *auxv, unsigned long pagesz, int os) {
   long i, rc;
   unsigned size;
diff --git a/libc/crt/crt.S b/libc/crt/crt.S
index 6d2a798df..07978f47b 100644
--- a/libc/crt/crt.S
+++ b/libc/crt/crt.S
@@ -62,6 +62,8 @@ _start:
 //	set operating system when already detected
 1:	mov	%cl,__hostos(%rip)
 
+	mov	%rdx,__program_executable_name(%rip)
+
 //	get startup timestamp as early as possible
 //	its used by --strace flag and kprintf() %T
 	rdtsc
diff --git a/libc/nexgen32e/program_executable_name2.c b/libc/nexgen32e/program_executable_name.c
similarity index 100%
rename from libc/nexgen32e/program_executable_name2.c
rename to libc/nexgen32e/program_executable_name.c