Sweden-Number/server/ptrace.c

166 lines
4.9 KiB
C

/*
* 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 */
/* wait for a ptraced child to get a certain signal */
/* if the signal is 0, we simply check if anything is pending and return at once */
void wait4_thread( struct thread *thread, int signal )
{
int status;
int pid;
restart:
pid = thread ? thread->unix_pid : -1;
if ((pid = wait4( pid, &status, WUNTRACED | (signal ? 0 : WNOHANG), NULL )) == -1)
{
perror( "wait4" );
return;
}
if (WIFSTOPPED(status))
{
int sig = WSTOPSIG(status);
if (debug_level) fprintf( stderr, "ptrace: pid %d got sig %d\n", pid, sig );
switch(sig)
{
case SIGSTOP: /* continue at once if not suspended */
if (!thread)
if (!(thread = get_thread_from_pid( pid ))) break;
if (!(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;
}
if (signal && sig != signal) goto restart;
}
else if (WIFSIGNALED(status))
{
int exit_code = WTERMSIG(status);
if (debug_level)
fprintf( stderr, "ptrace: pid %d killed by sig %d\n", pid, exit_code );
if (!thread)
if (!(thread = get_thread_from_pid( pid ))) return;
if (thread->client) remove_client( thread->client, exit_code );
}
else if (WIFEXITED(status))
{
int exit_code = WEXITSTATUS(status);
if (debug_level)
fprintf( stderr, "ptrace: pid %d exited with status %d\n", pid, exit_code );
if (!thread)
if (!(thread = get_thread_from_pid( pid ))) return;
if (thread->client) remove_client( thread->client, exit_code );
}
else fprintf( stderr, "wait4: pid %d unknown status %x\n", pid, status );
}
/* 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, "ptrace: attached to pid %d\n", thread->unix_pid );
thread->attached = 1;
wait4_thread( thread, SIGSTOP );
return 1;
}
/* detach from a Unix thread and kill it */
void detach_thread( struct thread *thread )
{
if (!thread->unix_pid) return;
kill( thread->unix_pid, SIGTERM );
if (thread->suspend + thread->process->suspend) continue_thread( thread );
if (thread->attached)
{
wait4_thread( thread, SIGTERM );
if (debug_level) fprintf( stderr, "ptrace: detaching from %d\n", thread->unix_pid );
ptrace( PTRACE_DETACH, thread->unix_pid, 1, SIGTERM );
thread->attached = 0;
}
}
/* 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 );
}
/* 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;
}