Redo manual syscalls, and use them for hooking.. And fix mmap, which now makes the whole thing slightly broken, because vm_remap into the middle of the shared region apparently silently does nothing.

1 files changed, 31 insertions, 44 deletions

diff --git a/lib/darwin/manual-syscall.h b/lib/darwin/manual-syscall.h
index 9f04d2b..b1bac7e 100644
--- a/lib/darwin/manual-syscall.h
+++ b/lib/darwin/manual-syscall.h
@@ -1,54 +1,41 @@
 #pragma once
 
-#define REG(var, reg) register long _##var __asm__(#reg) = var
-#define OREG(var, reg) register long var __asm__(#reg)
+#define GEN_SYSCALL(name, num) \
+    __asm__(".globl _manual_" #name "\n" \
+            ".pushsection __TEXT,__text,regular,pure_instructions\n" \
+            "_manual_" #name ":\n" \
+            ".set num, " #num "\n" \
+            GEN_SYSCALL_INNER() \
+            ".popsection\n")
 
-__attribute__((always_inline))
 #if defined(__x86_64__)
-static int manual_syscall(long s, long a, long b, long c, long d) {
-    if (s < 0)
-        s = -s | 1 << 24;
-    else
-        s |= 2 << 24;
-    REG(s, rax); REG(a, rdi); REG(b, rsi); REG(c, rdx); REG(d, rcx);
-    OREG(out, rax);
-    __asm__ volatile("syscall"
-                     : "=r"(out)
-                     : "r"(_s), "r"(_a), "r"(_b), "r"(_c), "r"(_d));
-    return out;
-}
+/* Look at me, I'm different! */
+#define GEN_SYSCALL_INNER() \
+    ".if num < 0\n" \
+        "mov $(-num | 1 << 24), %eax\n" \
+    ".else\n" \
+        "mov $( num | 2 << 24), %eax\n" \
+    ".endif\n" \
+    "mov %rcx, %r10\n" \
+    "syscall\n" \
+    "ret\n"
+
 #elif defined(__i386__)
-static int manual_syscall(long s, long a, long b, long c, long d) {
-    REG(s, eax);
-    OREG(out, eax);
-    __asm__ volatile("push %5; push %4; push %3; push %2; push $0;"
-                     "mov %%esp, %%ecx;"
-                     "call 1f; 1: pop %%edx; add $(2f-1b), %%edx;"
-                     "sysenter;"
-                     "2: add $(5 * 4), %%esp"
-                     : "=r"(out)
-                     : "r"(_s), "g"(a), "g"(b), "g"(c), "g"(d)
-                     : "edx", "ecx");
-    return out;
-}
+#define GEN_SYSCALL_INNER() \
+    "mov $num, %eax\n" \
+    "pop %edx\n" \
+    "mov %esp, %ecx\n" \
+    "sysenter\n"
 #elif defined(__arm__)
-static int manual_syscall(long s, long a, long b, long c, long d) {
-    REG(s, r12); REG(a, r0); REG(b, r1); REG(c, r2); REG(d, r3);
-    OREG(out, r0);
-    __asm__ volatile("svc #0x80"
-                     : "=r"(out)
-                     : "r"(_s), "r"(_a), "r"(_b), "r"(_c), "r"(_d));
-    return out;
-}
+#define GEN_SYSCALL_INNER() \
+    "mov r12, #num\n" \
+    "svc #0x80\n" \
+    "bx lr\n"
 #elif defined(__arm64__)
-static int manual_syscall(long s, long a, long b, long c, long d) {
-    REG(s, x16); REG(a, x0); REG(b, x1); REG(c, x2); REG(d, x3);
-    OREG(out, x0);
-    __asm__ volatile("svc #0x80"
-                     : "=r"(out)
-                     : "r"(_s), "r"(_a), "r"(_b), "r"(_c), "r"(_d));
-    return out;
-}
+#define GEN_SYSCALL_INNER() \
+    "mov x12, #num\n" \
+    "svc #0x80\n" \
+    "ret\n"
 #else
 #error ?
 #endif