| /* |
| * Server-side ptrace support |
| * |
| * Copyright (C) 1999 Alexandre Julliard |
| */ |
| |
| #include "config.h" |
| |
| #include <assert.h> |
| #include <errno.h> |
| #include <stdio.h> |
| #include <signal.h> |
| #include <sys/types.h> |
| #include <sys/ptrace.h> |
| #ifdef HAVE_SYS_WAIT_H |
| #include <sys/wait.h> |
| #endif |
| #include <unistd.h> |
| |
| #include "process.h" |
| #include "thread.h" |
| |
| |
| #ifndef PTRACE_CONT |
| #define PTRACE_CONT PT_CONTINUE |
| #endif |
| #ifndef PTRACE_ATTACH |
| #define PTRACE_ATTACH PT_ATTACH |
| #endif |
| #ifndef PTRACE_DETACH |
| #define PTRACE_DETACH PT_DETACH |
| #endif |
| #ifndef PTRACE_PEEKDATA |
| #define PTRACE_PEEKDATA PT_READ_D |
| #endif |
| #ifndef PTRACE_POKEDATA |
| #define PTRACE_POKEDATA PT_WRITE_D |
| #endif |
| |
| static const int use_ptrace = 1; /* set to 0 to disable ptrace */ |
| |
| /* handle a status returned by wait4 */ |
| static int handle_child_status( struct thread *thread, int pid, int status ) |
| { |
| if (WIFSTOPPED(status)) |
| { |
| int sig = WSTOPSIG(status); |
| if (debug_level && thread) |
| fprintf( stderr, "%08x: *signal* signal=%d\n", (unsigned int)thread, sig ); |
| switch(sig) |
| { |
| case SIGSTOP: /* continue at once if not suspended */ |
| if (!thread || !(thread->process->suspend + thread->suspend)) |
| ptrace( PTRACE_CONT, pid, 1, sig ); |
| break; |
| default: /* ignore other signals for now */ |
| ptrace( PTRACE_CONT, pid, 1, sig ); |
| break; |
| } |
| return sig; |
| } |
| if (thread && (WIFSIGNALED(status) || WIFEXITED(status))) |
| { |
| thread->attached = 0; |
| thread->unix_pid = 0; |
| if (debug_level) |
| { |
| if (WIFSIGNALED(status)) |
| fprintf( stderr, "%08x: *exited* signal=%d\n", |
| (unsigned int)thread, WTERMSIG(status) ); |
| else |
| fprintf( stderr, "%08x: *exited* status=%d\n", |
| (unsigned int)thread, WEXITSTATUS(status) ); |
| } |
| } |
| return 0; |
| } |
| |
| /* handle a SIGCHLD signal */ |
| void sigchld_handler() |
| { |
| int pid, status; |
| |
| for (;;) |
| { |
| if (!(pid = wait4( -1, &status, WUNTRACED | WNOHANG, NULL ))) break; |
| if (pid != -1) handle_child_status( get_thread_from_pid(pid), pid, status ); |
| else break; |
| } |
| } |
| |
| /* wait for a ptraced child to get a certain signal */ |
| void wait4_thread( struct thread *thread, int signal ) |
| { |
| int res, status; |
| |
| do |
| { |
| if ((res = wait4( thread->unix_pid, &status, WUNTRACED, NULL )) == -1) |
| { |
| perror( "wait4" ); |
| return; |
| } |
| res = handle_child_status( thread, res, status ); |
| } while (res && res != signal); |
| } |
| |
| /* attach to a Unix thread */ |
| static int attach_thread( struct thread *thread ) |
| { |
| /* this may fail if the client is already being debugged */ |
| if (!use_ptrace || (ptrace( PTRACE_ATTACH, thread->unix_pid, 0, 0 ) == -1)) return 0; |
| if (debug_level) fprintf( stderr, "%08x: *attached*\n", (unsigned int)thread ); |
| thread->attached = 1; |
| wait4_thread( thread, SIGSTOP ); |
| return 1; |
| } |
| |
| /* detach from a Unix thread and kill it */ |
| void detach_thread( struct thread *thread, int sig ) |
| { |
| if (!thread->unix_pid) return; |
| if (thread->attached) |
| { |
| /* make sure it is stopped */ |
| if (!(thread->suspend + thread->process->suspend)) stop_thread( thread ); |
| if (sig) kill( thread->unix_pid, sig ); |
| if (debug_level) fprintf( stderr, "%08x: *detached*\n", (unsigned int)thread ); |
| ptrace( PTRACE_DETACH, thread->unix_pid, 1, sig ); |
| thread->attached = 0; |
| } |
| else |
| { |
| if (sig) kill( thread->unix_pid, sig ); |
| if (thread->suspend + thread->process->suspend) continue_thread( thread ); |
| } |
| } |
| |
| /* stop a thread (at the Unix level) */ |
| void stop_thread( struct thread *thread ) |
| { |
| /* can't stop a thread while initialisation is in progress */ |
| if (!thread->unix_pid || thread->process->init_event) return; |
| /* first try to attach to it */ |
| if (!thread->attached) |
| if (attach_thread( thread )) return; /* this will have stopped it */ |
| /* attached already, or attach failed -> send a signal */ |
| kill( thread->unix_pid, SIGSTOP ); |
| if (thread->attached) wait4_thread( thread, SIGSTOP ); |
| } |
| |
| /* make a thread continue (at the Unix level) */ |
| void continue_thread( struct thread *thread ) |
| { |
| if (!thread->unix_pid) return; |
| if (!thread->attached) kill( thread->unix_pid, SIGCONT ); |
| else ptrace( PTRACE_CONT, thread->unix_pid, 1, SIGSTOP ); |
| } |
| |
| /* suspend a thread to allow using ptrace on it */ |
| /* you must do a resume_thread when finished with the thread */ |
| int suspend_for_ptrace( struct thread *thread ) |
| { |
| if (thread->attached) |
| { |
| suspend_thread( thread, 0 ); |
| return 1; |
| } |
| if (attach_thread( thread )) |
| { |
| /* the attach will have suspended it */ |
| thread->suspend++; |
| return 1; |
| } |
| set_error( STATUS_ACCESS_DENIED ); |
| return 0; |
| } |
| |
| /* read an int from a thread address space */ |
| int read_thread_int( struct thread *thread, const int *addr, int *data ) |
| { |
| if (((*data = ptrace( PTRACE_PEEKDATA, thread->unix_pid, addr, 0 )) == -1) && errno) |
| { |
| file_set_error(); |
| return -1; |
| } |
| return 0; |
| } |
| |
| /* write an int to a thread address space */ |
| int write_thread_int( struct thread *thread, int *addr, int data, unsigned int mask ) |
| { |
| int res; |
| if (mask != ~0) |
| { |
| if (read_thread_int( thread, addr, &res ) == -1) return -1; |
| data = (data & mask) | (res & ~mask); |
| } |
| if ((res = ptrace( PTRACE_POKEDATA, thread->unix_pid, addr, data )) == -1) file_set_error(); |
| return res; |
| } |