1 files changed, 173 insertions, 0 deletions
diff --git a/qemu_mode/hooking_bridge/src/patching.c b/qemu_mode/hooking_bridge/src/patching.c
new file mode 100644
index 00000000..123ad99d
--- /dev/null
+++ b/qemu_mode/hooking_bridge/src/patching.c
@@ -0,0 +1,173 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <dlfcn.h>
+#include <glib.h>
+#include "common.h"
+#include "exports.h"
+
+void        *handle;
+struct conf *config;
+struct conf *(*configure)();
+GByteArray *out;
+void       *cpu;
+char        cbuf[100];
+
+// region GDB Imports
+#pragma region GDB Imports
+void           cpu_single_step(void *cpu, int enabled);
+int            get_sstep_flags(void);
+void           gdb_accept_init(int fd);
+int            gdb_breakpoint_insert(int type, unsigned long long addr,
+                                     unsigned long long len);
+int            gdb_breakpoint_remove(int type, unsigned long long addr,
+                                     unsigned long long len);
+void          *qemu_get_cpu(int index);
+int  target_memory_rw_debug(void *cpu, unsigned long long addr, void *ptr,
+                            unsigned long long len, char is_write);
+int  gdb_read_register(void *cs, GByteArray *mem_buf, int n);
+int  gdb_write_register(void *cs, char *mem_buf, int n);
+void gdb_set_cpu_pc(unsigned long long pc);
+void gdb_continue(void);
+#pragma endregion GDB Imports
+
+// region API
+int r_mem(unsigned long long addr, unsigned long long len, void *dest) {
+
+  return target_memory_rw_debug(cpu, addr, dest, len, 0);
+
+}
+
+int w_mem(unsigned long long addr, unsigned long long len, void *src) {
+
+  return target_memory_rw_debug(cpu, addr, src, len, 1);
+
+}
+
+int r_reg(unsigned char reg, void *dest) {
+
+  g_byte_array_steal(out, NULL);
+  int op = gdb_read_register(cpu, out, reg);
+  memcpy(dest, out->data, out->len);
+  return op;
+
+}
+
+int w_reg(unsigned char reg, char *src) {
+
+  return gdb_write_register(cpu, src, reg);
+
+}
+
+// region Breakpoint handling
+char               single_stepped;
+unsigned long long gen_addr;
+struct ret *(*hook)();
+struct ret *returned;
+// Defined and imported gdbstub.c
+void set_signal_callback(void (*cb)(int));
+// Breakpoints are set here
+void patch_block_trans_cb(struct qemu_plugin_tb *tb) {
+
+  unsigned long long addr;
+  addr = qemu_plugin_tb_vaddr(tb);
+
+  if (addr == config->entry_addr) {
+
+    // NOTE This means we cannot put a BP in the first basic block
+    gdb_accept_init(-1);
+    for (int i = 0; i < config->num_hooks; i++) {
+
+      gdb_breakpoint_insert(0, config->hooks[i], 1);
+
+    }
+
+  }
+
+}
+
+void handle_signal_callback(int sig) {
+
+  if (single_stepped) {
+
+    single_stepped = 0;
+    gdb_breakpoint_insert(0, gen_addr, 1);
+    cpu_single_step(cpu, 0);
+    gdb_continue();
+    return;
+
+  }
+
+  r_reg(config->IP_reg_num, cbuf);
+  gen_addr = *(unsigned long long *)cbuf;
+
+  sprintf(cbuf, "hook_%016llx", gen_addr);
+  // TODO maybe find a way to put the hook function pointers in the TCG data
+  // structure instead of this dlsym call
+  *(unsigned long long **)(&hook) = dlsym(handle, cbuf);
+  if (!hook) {
+
+    exit(-1);
+
+  }
+
+  returned = hook();
+
+  if (returned->remove_bp ||
+      (returned->addr ==
+       gen_addr)) {  //* force removal of bp in returning to the same address,
+                     //otherwise hook will be called again
+    gdb_breakpoint_remove(0, gen_addr, 1);
+
+  }
+
+  if (returned->addr == gen_addr) {
+
+    single_stepped = 1;
+    cpu_single_step(cpu, get_sstep_flags());
+
+  } else {
+
+    //* no need to rexecute the IP instruction
+    gdb_set_cpu_pc(returned->addr);
+
+  }
+
+  gdb_continue();
+
+}
+
+// region Constructor/Destructor
+void patch_finish_cb(void *userdata) {
+
+  g_byte_array_free(out, 1);
+  dlclose(handle);
+
+}
+
+void patch_vpu_init_cb(unsigned int vcpu_index) {
+
+  cpu = qemu_get_cpu(vcpu_index);
+
+}
+
+void patch_init(char *hook_lib) {
+
+  // TODO make OS agnostic, remove dlopen
+  handle = dlopen(hook_lib, RTLD_NOW);
+  if (!handle) {
+
+    fprintf(stderr, "DLOPEN Error: %s\n", dlerror());
+    exit(-1);
+
+  }
+
+  single_stepped = 0;
+
+  *(void **)(&configure) = dlsym(handle, "configure");
+  config = configure();
+
+  set_signal_callback(handle_signal_callback);
+  out = g_byte_array_new();
+
+}
+