src/monitor/ptrace/Portal.cpp

   1 #include <iostream>
   2 #include <sys/user.h>
   3 #include <sys/ptrace.h>
   4 #include <sys/types.h>
   5 #include <sys/wait.h>
   6 #include <unistd.h>
   7 #include <errno.h>
   8 #include <signal.h>
   9 #include <cstring>
  10 #include <iostream>
  11
  12 #include "Portal.h"
  13
  14 #include "ExitObserver.h"
  15 #include "TrapObserver.h"
  16
  17 #include "Message.h"
  18
  19 namespace Aesalon {
  20 namespace Monitor {
  21 namespace PTrace {
  22
  23 Portal::Portal(Misc::SmartPointer<Platform::ArgumentList> argument_list) : pid(0) {
  24
  25     pid = fork();
  26     if(pid == -1)
  27         throw PTraceException(Misc::StreamAsString() << "Forking to create child process failed: " << strerror(errno));
  28     else if(pid == 0) {
  29         ptrace(PTRACE_TRACEME, 0, NULL, NULL);
  30         if(execv(argument_list->get_argument(0).c_str(), argument_list->get_as_argv()) == -1) {
  31             throw PTraceException(Misc::StreamAsString() << "Failed to execute process: " << strerror(errno));
  32         }
  33     }
  34
  35     /*ptrace(PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACESYSGOOD);*/
  36
  37     add_signal_observer(new ExitObserver());
  38     add_signal_observer(new TrapObserver());
  39 }
  40
  41 Platform::MemoryAddress Portal::get_register(register_e which) const {
  42     struct user_regs_struct registers;
  43     if(ptrace(PTRACE_GETREGS, pid, NULL, &registers) == -1)
  44         throw PTraceException(Misc::StreamAsString() << "Couldn't get register values: " << strerror(errno));
  45
  46     switch(which) {
  47 #if AESALON_PLATFORM == AESALON_PLATFORM_x86_64
  48         case RAX:
  49             std::cout << "Value of RAX requested; RAX is " << registers.rax << ", ORIG_RAX is " << registers.orig_rax << std::endl;
  50             return registers.orig_rax;
  51         case RBX:
  52             return registers.rbx;
  53         case RIP:
  54             return registers.rip;
  55 #endif
  56         default:
  57             throw PTraceException("Value of invalid register requested");
  58     }
  59 }
  60
  61 Word Portal::read_memory(Platform::MemoryAddress address) const {
  62     SWord return_value = ptrace(PTRACE_PEEKDATA, pid, address, NULL);
  63     if(return_value == -1 && errno != 0)
  64         throw PTraceException(Misc::StreamAsString() << "Couldn't read memory: " << strerror(errno));
  65     /* NOTE: what happens if return_value is < 0? . ..  */
  66     return return_value;
  67 }
  68
  69 void Portal::write_memory(Platform::MemoryAddress address, Word value) {
  70     if(ptrace(PTRACE_POKEDATA, pid, address, value) == -1)
  71         throw PTraceException(Misc::StreamAsString() << "Couldn't write memory: " << strerror(errno));
  72 }
  73
  74 void Portal::write_memory(Platform::MemoryAddress address, Byte value) {
  75     Word current_value = read_memory(address);
  76     current_value &= ~0xff;
  77     write_memory(address, current_value | value);
  78 }
  79
  80 void Portal::attach() {
  81     ptrace(PTRACE_ATTACH, pid, NULL, NULL);
  82 }
  83
  84 void Portal::place_breakpoint(Platform::MemoryAddress address) {
  85     Byte original = read_memory(address) & 0xff;
  86     add_breakpoint(new Breakpoint(address, original));
  87     write_memory(address, Byte(0xcc));
  88 }
  89
  90 Misc::SmartPointer<Breakpoint> Portal::get_breakpoint_by_id(std::size_t which) const {
  91     for(breakpoint_list_t::const_iterator i = breakpoint_list.begin(); i != breakpoint_list.end(); i ++) {
  92         if((*i)->get_id() == which) return *i;
  93     }
  94     return NULL;
  95 }
  96
  97 Misc::SmartPointer<Breakpoint> Portal::get_breakpoint_by_address(Platform::MemoryAddress address) const {
  98     for(breakpoint_list_t::const_iterator i = breakpoint_list.begin(); i != breakpoint_list.end(); i ++) {
  99         if((*i)->get_address() == address) return *i;
 100     }
 101     return NULL;
 102 }
 103
 104
 105 void Portal::handle_signal() {
 106     int signal;
 107     int status = wait_for_signal();
 108     if(!WIFEXITED(status) && WIFSTOPPED(status)) {
 109         siginfo_t signal_info;
 110         if(ptrace(PTRACE_GETSIGINFO, pid, NULL, &signal_info) == -1) {
 111             throw PTraceException(Misc::StreamAsString() << "Failed to get signal information: " << strerror(errno));
 112         }
 113         signal = signal_info.si_signo;
 114     }
 115     else signal = -1;
 116
 117     std::cout << "Portal::handle_signal(): status: (" << status << "): ";
 118
 119     for(int mask = 1 << 20; mask > 0; mask >>= 1) {
 120         std::cout << ((status & mask)?"1":"0");
 121     }
 122
 123     std::cout << ", signal: " << signal << std::endl;
 124
 125     for(signal_observer_list_t::iterator i = signal_observer_list.begin(); i != signal_observer_list.end(); i ++) {
 126         if((*i)->handle_signal(signal, status)) return;
 127     }
 128 }
 129
 130 void Portal::continue_execution(int signal) {
 131     if(ptrace(PTRACE_CONT, pid, NULL, NULL) == -1)
 132         throw PTraceException(Misc::StreamAsString() << "Couldn't continue program execution: " << strerror(errno));
 133 }
 134
 135 void Portal::single_step() {
 136     if(ptrace(PTRACE_SINGLESTEP, pid, NULL, NULL) == -1)
 137         throw PTraceException(Misc::StreamAsString() << "Couldn't single-step program:" << strerror(errno));
 138 }
 139
 140 int Portal::wait_for_signal() {
 141     int status;
 142     if(waitpid(pid, &status, 0) == -1) throw PTraceException(Misc::StreamAsString() << "Couldn't waitpid() on child: " << strerror(errno));
 143     return status;
 144 }
 145
 146 void Portal::handle_breakpoint() {
 147     Misc::SmartPointer<Breakpoint> breakpoint = get_breakpoint_by_address(get_register(RIP));
 148     if(!breakpoint.is_valid()) {
 149         Message(Message::DEBUG_MESSAGE, "handle_breakpoint() called on non-breakpoint");
 150         return;
 151     }
 152     write_memory(breakpoint->get_address(), breakpoint->get_original());
 153     single_step();
 154     write_memory(breakpoint->get_address(), breakpoint->get_breakpoint_character());
 155 }
 156
 157 } // namespace PTrace
 158 } // namespace Monitor
 159 } // namespace Aesalon