2 files changed, 42 insertions, 67 deletions

diff --git a/hypodermic/process.py b/hypodermic/process.py
index 9a321e0..8307e08 100644
--- a/hypodermic/process.py
+++ b/hypodermic/process.py
@@ -136,10 +136,9 @@ class Process(object):
         self._attach = self._so.attach
         self._detach = self._so.detach
         self._cont = self._so.cont
-        self._getreg32 = self._so.getreg32
-        self._getreg32.restype = ctypes.c_ulong
-        self._getreg64 = self._so.getreg64
-        self._getreg64.restype = ctypes.c_ulonglong
+        self._isamd64 = self._so.is_amd64
+        self._getreg = self._so.getreg
+        self._getreg.restype = ctypes.c_ulonglong
 
     def detach(self):
         """Explicitly detaches from the process.
@@ -210,25 +209,40 @@ class Process(object):
     def get_register(self, reg: str) -> int:
         """Returns the value of the given register.
 
+        Note:
+            Registers are tied to the host processor, not the target
+            processor. For example, a 32-bit ELF will still have 64-bit
+            registers on 64-bit Linux.
+
         Args:
             reg (str): The register to inspect. (e.g. "rax")
 
         Returns:
             An integer representing the value of the register.
+
         """
-        regs = AMD64_INDICES if self.arch == "x64" else I386_INDICES
+        regs = AMD64_INDICES if self._isamd64 else I386_INDICES
 
         if reg not in regs:
             raise ValueError("{} is not a valid register".format(reg))
 
-        if self.arch == "x64":
-            return self._getreg64(self.pid, regs.get(reg))
-        return self._getreg32(self.pid, regs.get(reg))
+        return self._getreg(self.pid, regs.get(reg))
 
     @property
     def arch(self) -> str:
-        with open("/proc/{}/exe".format(self.pid), "rb") as elf:
-            return ELFFile(elf).get_machine_arch()
+        """Returns the architecture of the host processor.
+
+        Note:
+            The architecture of the host platform is not necessarily
+            the architecture of the target executable. However, this
+            value will accurately represent how registers should be
+            addressed.
+
+        Returns:
+            A string representing the host processor. As of now, only
+            "x64" and "x86" are supported.
+        """
+        return "x64" if self._isamd64 else "x86"
 
     @property
     def maps(self) -> list:
diff --git a/wrapper/ptrace.c b/wrapper/ptrace.c
index 7e5dfa8..8517519 100644
--- a/wrapper/ptrace.c
+++ b/wrapper/ptrace.c
@@ -19,9 +19,12 @@
 
 #include <sys/ptrace.h>
 #include <sys/types.h>
+#include <sys/user.h>
+#include <sys/utsname.h>
 #include <sys/wait.h>
 
 #include <stddef.h>
+#include <string.h>
 #include <unistd.h>
 
 
@@ -86,73 +89,31 @@ int cont(int pid) {
 }
 
 
-/* user_regs_struct is copied from sys/user.h so that we can debug a
-   32-bit executable on a 64-bit platform. */
-struct amd64_user_regs_struct {
-    __extension__ unsigned long long r15;
-    __extension__ unsigned long long r14;
-    __extension__ unsigned long long r13;
-    __extension__ unsigned long long r12;
-    __extension__ unsigned long long rbp;
-    __extension__ unsigned long long rbx;
-    __extension__ unsigned long long r11;
-    __extension__ unsigned long long r10;
-    __extension__ unsigned long long r9;
-    __extension__ unsigned long long r8;
-    __extension__ unsigned long long rax;
-    __extension__ unsigned long long rcx;
-    __extension__ unsigned long long rdx;
-    __extension__ unsigned long long rsi;
-    __extension__ unsigned long long rdi;
-    __extension__ unsigned long long orig_rax;
-    __extension__ unsigned long long rip;
-    __extension__ unsigned long long cs;
-    __extension__ unsigned long long eflags;
-    __extension__ unsigned long long rsp;
-    __extension__ unsigned long long ss;
-    __extension__ unsigned long long fs_base;
-    __extension__ unsigned long long gs_base;
-    __extension__ unsigned long long ds;
-    __extension__ unsigned long long es;
-    __extension__ unsigned long long fs;
-    __extension__ unsigned long long gs;
-};
+/* TODO: As of now, Hypodermis is strongly tied to the Intel x86
+   family of processors. This should really be expanded. */
+int is_amd64(void) {
+    struct utsname ub;
 
+    uname(&ub);
 
-struct i386_user_regs_struct {
-    unsigned long ebx;
-    unsigned long ecx;
-    unsigned long edx;
-    unsigned long esi;
-    unsigned long edi;
-    unsigned long ebp;
-    unsigned long eax;
-    unsigned long xds;
-    unsigned long xes;
-    unsigned long xfs;
-    unsigned long xgs;
-    unsigned long orig_eax;
-    unsigned long eip;
-    unsigned long xcs;
-    unsigned long eflags;
-    unsigned long esp;
-    unsigned long xss;
-};
+    return !strcmp(ub.machine, "x86_64");
+}
 
 
-unsigned long long getreg64(int pid, int idx) {
-    struct amd64_user_regs_struct regs;
+#ifdef __x86_64__
+unsigned long long getreg(int pid, int idx) {
+    struct user_regs_struct regs;
 
     ptrace(PTRACE_GETREGS, pid, NULL, &regs);
 
     return ((unsigned long long *) &regs)[idx];
 }
-
-
-unsigned long getreg32(int pid, int idx) {
-    struct i386_user_regs_struct regs;
+#else
+unsigned long getreg(int pid, int idx) {
+    struct user_regs_struct regs;
 
     ptrace(PTRACE_GETREGS, pid, NULL, &regs);
 
-    return ((unsigned long  *) &regs)[idx];
+    return ((unsigned long *) &regs)[idx];
 }
+#endif