From cd4f34992e707f91eed63f42ac14bd0b389baec3 Mon Sep 17 00:00:00 2001
From: June McEnroe <june@causal.agency>
Date: Thu, 6 Oct 2016 01:28:19 -0400
Subject: Use custom typedefs in jrp

---
 .bin/jrp.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

(limited to '.bin/jrp.c')

diff --git a/.bin/jrp.c b/.bin/jrp.c
index cd5dbb82..72a9c303 100755
--- a/.bin/jrp.c
+++ b/.bin/jrp.c
@@ -3,13 +3,16 @@ exec cc -Wall -Wextra $@ -o $(dirname $0)/jrp $0
 #endif
 
 #include <err.h>
-#include <stdint.h>
 #include <stdio.h>
 #include <sys/mman.h>
 #include <sysexits.h>
 #include <unistd.h>
 
-enum op {
+typedef unsigned long long op;
+typedef long long value;
+typedef value *(*fptr)(value *);
+
+enum {
     OP_PROL = 0x90fc8948e5894855, // push ebp; mov rbp, rsp; mov rsp, rdi
     OP_EPIL = 0xc35dec8948e08948, // mov rax, rsp; mov rsp, rbp; pop rbp; ret
     OP_CALL = 0x90666666d0ff5f58, // pop rax; pop rdi; call rax
@@ -31,20 +34,18 @@ enum op {
     OP_SHR  = 0x906666242cd34859, // pop rcx; shr qword [rsp], cl
 };
 
-typedef int64_t *(*fptr)(int64_t *);
-
 int main() {
     int error;
     int page = getpagesize();
 
-    int64_t *stack = mmap(0, page, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, 0, 0);
-    if (stack == MAP_FAILED) err(EX_OSERR, "mmap");
-    int64_t *stack_ptr = stack + page / sizeof(int64_t);
+    value *base = mmap(0, page, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, 0, 0);
+    if (base == MAP_FAILED) err(EX_OSERR, "mmap");
+    value *stack = base + page / sizeof(value);
 
-    enum op *ops = mmap(0, page, PROT_WRITE, MAP_ANON | MAP_PRIVATE, 0, 0);
+    op *ops = mmap(0, page, PROT_WRITE, MAP_ANON | MAP_PRIVATE, 0, 0);
     if (ops == MAP_FAILED) err(EX_OSERR, "mmap");
 
-    enum op *p = ops;
+    op *p = ops;
     *p++ = OP_PROL;
     *p++ = OP_PUSH | (1 << 8);
     *p++ = OP_PUSH | (2 << 8);
@@ -57,9 +58,9 @@ int main() {
     if (error) err(EX_OSERR, "mprotect");
 
     fptr fn = (fptr) ops;
-    stack_ptr = fn(stack_ptr);
+    stack = fn(stack);
 
-    printf("%lld\n", *stack_ptr);
+    printf("%lld\n", *stack);
 
     return 0;
 }
-- 
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