484 lines
12 KiB
C
484 lines
12 KiB
C
/*
|
|
* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
|
|
* Licensed under the GPL
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <stdarg.h>
|
|
#include <unistd.h>
|
|
#include <signal.h>
|
|
#include <errno.h>
|
|
#include <sched.h>
|
|
#include <string.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/time.h>
|
|
#include <sys/wait.h>
|
|
#include "user.h"
|
|
#include "sysdep/ptrace.h"
|
|
#include "sigcontext.h"
|
|
#include "sysdep/sigcontext.h"
|
|
#include "os.h"
|
|
#include "user_util.h"
|
|
#include "mem_user.h"
|
|
#include "process.h"
|
|
#include "kern_util.h"
|
|
#include "chan_user.h"
|
|
#include "ptrace_user.h"
|
|
#include "irq_user.h"
|
|
#include "mode.h"
|
|
#include "tt.h"
|
|
|
|
static int tracer_winch[2];
|
|
|
|
int is_tracer_winch(int pid, int fd, void *data)
|
|
{
|
|
if(pid != os_getpgrp())
|
|
return(0);
|
|
|
|
register_winch_irq(tracer_winch[0], fd, -1, data);
|
|
return(1);
|
|
}
|
|
|
|
static void tracer_winch_handler(int sig)
|
|
{
|
|
int n;
|
|
char c = 1;
|
|
|
|
n = os_write_file(tracer_winch[1], &c, sizeof(c));
|
|
if(n != sizeof(c))
|
|
printk("tracer_winch_handler - write failed, err = %d\n", -n);
|
|
}
|
|
|
|
/* Called only by the tracing thread during initialization */
|
|
|
|
static void setup_tracer_winch(void)
|
|
{
|
|
int err;
|
|
|
|
err = os_pipe(tracer_winch, 1, 1);
|
|
if(err < 0){
|
|
printk("setup_tracer_winch : os_pipe failed, err = %d\n", -err);
|
|
return;
|
|
}
|
|
signal(SIGWINCH, tracer_winch_handler);
|
|
}
|
|
|
|
void attach_process(int pid)
|
|
{
|
|
if((ptrace(PTRACE_ATTACH, pid, 0, 0) < 0) ||
|
|
(ptrace(PTRACE_CONT, pid, 0, 0) < 0))
|
|
tracer_panic("OP_FORK failed to attach pid");
|
|
wait_for_stop(pid, SIGSTOP, PTRACE_CONT, NULL);
|
|
if (ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0)
|
|
tracer_panic("OP_FORK: PTRACE_SETOPTIONS failed, errno = %d", errno);
|
|
if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
|
|
tracer_panic("OP_FORK failed to continue process");
|
|
}
|
|
|
|
void tracer_panic(char *format, ...)
|
|
{
|
|
va_list ap;
|
|
|
|
va_start(ap, format);
|
|
vprintf(format, ap);
|
|
va_end(ap);
|
|
printf("\n");
|
|
while(1) pause();
|
|
}
|
|
|
|
static void tracer_segv(int sig, struct sigcontext sc)
|
|
{
|
|
struct faultinfo fi;
|
|
GET_FAULTINFO_FROM_SC(fi, &sc);
|
|
printf("Tracing thread segfault at address 0x%lx, ip 0x%lx\n",
|
|
FAULT_ADDRESS(fi), SC_IP(&sc));
|
|
while(1)
|
|
pause();
|
|
}
|
|
|
|
/* Changed early in boot, and then only read */
|
|
int debug = 0;
|
|
int debug_stop = 1;
|
|
int debug_parent = 0;
|
|
int honeypot = 0;
|
|
|
|
static int signal_tramp(void *arg)
|
|
{
|
|
int (*proc)(void *);
|
|
|
|
if(honeypot && munmap((void *) (host_task_size - 0x10000000),
|
|
0x10000000))
|
|
panic("Unmapping stack failed");
|
|
if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0)
|
|
panic("ptrace PTRACE_TRACEME failed");
|
|
os_stop_process(os_getpid());
|
|
change_sig(SIGWINCH, 0);
|
|
signal(SIGUSR1, SIG_IGN);
|
|
change_sig(SIGCHLD, 0);
|
|
signal(SIGSEGV, (__sighandler_t) sig_handler);
|
|
set_cmdline("(idle thread)");
|
|
set_init_pid(os_getpid());
|
|
init_irq_signals(0);
|
|
proc = arg;
|
|
return((*proc)(NULL));
|
|
}
|
|
|
|
static void sleeping_process_signal(int pid, int sig)
|
|
{
|
|
switch(sig){
|
|
/* These two result from UML being ^Z-ed and bg-ed. PTRACE_CONT is
|
|
* right because the process must be in the kernel already.
|
|
*/
|
|
case SIGCONT:
|
|
case SIGTSTP:
|
|
if(ptrace(PTRACE_CONT, pid, 0, sig) < 0)
|
|
tracer_panic("sleeping_process_signal : Failed to "
|
|
"continue pid %d, signal = %d, "
|
|
"errno = %d\n", pid, sig, errno);
|
|
break;
|
|
|
|
/* This happens when the debugger (e.g. strace) is doing system call
|
|
* tracing on the kernel. During a context switch, the current task
|
|
* will be set to the incoming process and the outgoing process will
|
|
* hop into write and then read. Since it's not the current process
|
|
* any more, the trace of those will land here. So, we need to just
|
|
* PTRACE_SYSCALL it.
|
|
*/
|
|
case (SIGTRAP + 0x80):
|
|
if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
|
|
tracer_panic("sleeping_process_signal : Failed to "
|
|
"PTRACE_SYSCALL pid %d, errno = %d\n",
|
|
pid, errno);
|
|
break;
|
|
case SIGSTOP:
|
|
break;
|
|
default:
|
|
tracer_panic("sleeping process %d got unexpected "
|
|
"signal : %d\n", pid, sig);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Accessed only by the tracing thread */
|
|
int debugger_pid = -1;
|
|
int debugger_parent = -1;
|
|
int debugger_fd = -1;
|
|
int gdb_pid = -1;
|
|
|
|
struct {
|
|
int pid;
|
|
int signal;
|
|
unsigned long addr;
|
|
struct timeval time;
|
|
} signal_record[1024][32];
|
|
|
|
int signal_index[32];
|
|
int nsignals = 0;
|
|
int debug_trace = 0;
|
|
extern int io_nsignals, io_count, intr_count;
|
|
|
|
extern void signal_usr1(int sig);
|
|
|
|
int tracing_pid = -1;
|
|
|
|
int tracer(int (*init_proc)(void *), void *sp)
|
|
{
|
|
void *task = NULL;
|
|
int status, pid = 0, sig = 0, cont_type, tracing = 0, op = 0;
|
|
int proc_id = 0, n, err, old_tracing = 0, strace = 0;
|
|
int local_using_sysemu = 0;
|
|
#ifdef UML_CONFIG_SYSCALL_DEBUG
|
|
unsigned long eip = 0;
|
|
int last_index;
|
|
#endif
|
|
signal(SIGPIPE, SIG_IGN);
|
|
setup_tracer_winch();
|
|
tracing_pid = os_getpid();
|
|
printf("tracing thread pid = %d\n", tracing_pid);
|
|
|
|
pid = clone(signal_tramp, sp, CLONE_FILES | SIGCHLD, init_proc);
|
|
CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
|
|
if(n < 0){
|
|
printf("waitpid on idle thread failed, errno = %d\n", errno);
|
|
exit(1);
|
|
}
|
|
if (ptrace(PTRACE_OLDSETOPTIONS, pid, 0, (void *)PTRACE_O_TRACESYSGOOD) < 0) {
|
|
printf("Failed to PTRACE_SETOPTIONS for idle thread, errno = %d\n", errno);
|
|
exit(1);
|
|
}
|
|
if((ptrace(PTRACE_CONT, pid, 0, 0) < 0)){
|
|
printf("Failed to continue idle thread, errno = %d\n", errno);
|
|
exit(1);
|
|
}
|
|
|
|
signal(SIGSEGV, (sighandler_t) tracer_segv);
|
|
signal(SIGUSR1, signal_usr1);
|
|
if(debug_trace){
|
|
printf("Tracing thread pausing to be attached\n");
|
|
stop();
|
|
}
|
|
if(debug){
|
|
if(gdb_pid != -1)
|
|
debugger_pid = attach_debugger(pid, gdb_pid, 1);
|
|
else debugger_pid = init_ptrace_proxy(pid, 1, debug_stop);
|
|
if(debug_parent){
|
|
debugger_parent = os_process_parent(debugger_pid);
|
|
init_parent_proxy(debugger_parent);
|
|
err = attach(debugger_parent);
|
|
if(err){
|
|
printf("Failed to attach debugger parent %d, "
|
|
"errno = %d\n", debugger_parent, -err);
|
|
debugger_parent = -1;
|
|
}
|
|
else {
|
|
if(ptrace(PTRACE_SYSCALL, debugger_parent,
|
|
0, 0) < 0){
|
|
printf("Failed to continue debugger "
|
|
"parent, errno = %d\n", errno);
|
|
debugger_parent = -1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
set_cmdline("(tracing thread)");
|
|
while(1){
|
|
CATCH_EINTR(pid = waitpid(-1, &status, WUNTRACED));
|
|
if(pid <= 0){
|
|
if(errno != ECHILD){
|
|
printf("wait failed - errno = %d\n", errno);
|
|
}
|
|
continue;
|
|
}
|
|
if(pid == debugger_pid){
|
|
int cont = 0;
|
|
|
|
if(WIFEXITED(status) || WIFSIGNALED(status))
|
|
debugger_pid = -1;
|
|
/* XXX Figure out how to deal with gdb and SMP */
|
|
else cont = debugger_signal(status, cpu_tasks[0].pid);
|
|
if(cont == PTRACE_SYSCALL) strace = 1;
|
|
continue;
|
|
}
|
|
else if(pid == debugger_parent){
|
|
debugger_parent_signal(status, pid);
|
|
continue;
|
|
}
|
|
nsignals++;
|
|
if(WIFEXITED(status)) ;
|
|
#ifdef notdef
|
|
{
|
|
printf("Child %d exited with status %d\n", pid,
|
|
WEXITSTATUS(status));
|
|
}
|
|
#endif
|
|
else if(WIFSIGNALED(status)){
|
|
sig = WTERMSIG(status);
|
|
if(sig != 9){
|
|
printf("Child %d exited with signal %d\n", pid,
|
|
sig);
|
|
}
|
|
}
|
|
else if(WIFSTOPPED(status)){
|
|
proc_id = pid_to_processor_id(pid);
|
|
sig = WSTOPSIG(status);
|
|
#ifdef UML_CONFIG_SYSCALL_DEBUG
|
|
if(signal_index[proc_id] == 1024){
|
|
signal_index[proc_id] = 0;
|
|
last_index = 1023;
|
|
}
|
|
else last_index = signal_index[proc_id] - 1;
|
|
if(((sig == SIGPROF) || (sig == SIGVTALRM) ||
|
|
(sig == SIGALRM)) &&
|
|
(signal_record[proc_id][last_index].signal == sig)&&
|
|
(signal_record[proc_id][last_index].pid == pid))
|
|
signal_index[proc_id] = last_index;
|
|
signal_record[proc_id][signal_index[proc_id]].pid = pid;
|
|
gettimeofday(&signal_record[proc_id][signal_index[proc_id]].time, NULL);
|
|
eip = ptrace(PTRACE_PEEKUSR, pid, PT_IP_OFFSET, 0);
|
|
signal_record[proc_id][signal_index[proc_id]].addr = eip;
|
|
signal_record[proc_id][signal_index[proc_id]++].signal = sig;
|
|
#endif
|
|
if(proc_id == -1){
|
|
sleeping_process_signal(pid, sig);
|
|
continue;
|
|
}
|
|
|
|
task = cpu_tasks[proc_id].task;
|
|
tracing = is_tracing(task);
|
|
old_tracing = tracing;
|
|
|
|
/* Assume: no syscall, when coming from user */
|
|
if ( tracing )
|
|
do_sigtrap(task);
|
|
|
|
switch(sig){
|
|
case SIGUSR1:
|
|
sig = 0;
|
|
op = do_proc_op(task, proc_id);
|
|
switch(op){
|
|
/*
|
|
* This is called when entering user mode; after
|
|
* this, we start intercepting syscalls.
|
|
*
|
|
* In fact, a process is started in kernel mode,
|
|
* so with is_tracing() == 0 (and that is reset
|
|
* when executing syscalls, since UML kernel has
|
|
* the right to do syscalls);
|
|
*/
|
|
case OP_TRACE_ON:
|
|
arch_leave_kernel(task, pid);
|
|
tracing = 1;
|
|
break;
|
|
case OP_REBOOT:
|
|
case OP_HALT:
|
|
unmap_physmem();
|
|
kmalloc_ok = 0;
|
|
os_kill_ptraced_process(pid, 0);
|
|
/* Now let's reap remaining zombies */
|
|
errno = 0;
|
|
do {
|
|
waitpid(-1, &status,
|
|
WUNTRACED);
|
|
} while (errno != ECHILD);
|
|
return(op == OP_REBOOT);
|
|
case OP_NONE:
|
|
printf("Detaching pid %d\n", pid);
|
|
detach(pid, SIGSTOP);
|
|
continue;
|
|
default:
|
|
break;
|
|
}
|
|
/* OP_EXEC switches host processes on us,
|
|
* we want to continue the new one.
|
|
*/
|
|
pid = cpu_tasks[proc_id].pid;
|
|
break;
|
|
case (SIGTRAP + 0x80):
|
|
if(!tracing && (debugger_pid != -1)){
|
|
child_signal(pid, status & 0x7fff);
|
|
continue;
|
|
}
|
|
tracing = 0;
|
|
/* local_using_sysemu has been already set
|
|
* below, since if we are here, is_tracing() on
|
|
* the traced task was 1, i.e. the process had
|
|
* already run through one iteration of the
|
|
* loop which executed a OP_TRACE_ON request.*/
|
|
do_syscall(task, pid, local_using_sysemu);
|
|
sig = SIGUSR2;
|
|
break;
|
|
case SIGTRAP:
|
|
if(!tracing && (debugger_pid != -1)){
|
|
child_signal(pid, status);
|
|
continue;
|
|
}
|
|
tracing = 0;
|
|
break;
|
|
case SIGPROF:
|
|
if(tracing) sig = 0;
|
|
break;
|
|
case SIGCHLD:
|
|
case SIGHUP:
|
|
sig = 0;
|
|
break;
|
|
case SIGSEGV:
|
|
case SIGIO:
|
|
case SIGALRM:
|
|
case SIGVTALRM:
|
|
case SIGFPE:
|
|
case SIGBUS:
|
|
case SIGILL:
|
|
case SIGWINCH:
|
|
|
|
default:
|
|
tracing = 0;
|
|
break;
|
|
}
|
|
set_tracing(task, tracing);
|
|
|
|
if(!tracing && old_tracing)
|
|
arch_enter_kernel(task, pid);
|
|
|
|
if(!tracing && (debugger_pid != -1) && (sig != 0) &&
|
|
(sig != SIGALRM) && (sig != SIGVTALRM) &&
|
|
(sig != SIGSEGV) && (sig != SIGTRAP) &&
|
|
(sig != SIGUSR2) && (sig != SIGIO) &&
|
|
(sig != SIGFPE)){
|
|
child_signal(pid, status);
|
|
continue;
|
|
}
|
|
|
|
local_using_sysemu = get_using_sysemu();
|
|
|
|
if(tracing)
|
|
cont_type = SELECT_PTRACE_OPERATION(local_using_sysemu,
|
|
singlestepping(task));
|
|
else if((debugger_pid != -1) && strace)
|
|
cont_type = PTRACE_SYSCALL;
|
|
else
|
|
cont_type = PTRACE_CONT;
|
|
|
|
if(ptrace(cont_type, pid, 0, sig) != 0){
|
|
tracer_panic("ptrace failed to continue "
|
|
"process - errno = %d\n",
|
|
errno);
|
|
}
|
|
}
|
|
}
|
|
return(0);
|
|
}
|
|
|
|
static int __init uml_debug_setup(char *line, int *add)
|
|
{
|
|
char *next;
|
|
|
|
debug = 1;
|
|
*add = 0;
|
|
if(*line != '=') return(0);
|
|
line++;
|
|
|
|
while(line != NULL){
|
|
next = strchr(line, ',');
|
|
if(next) *next++ = '\0';
|
|
|
|
if(!strcmp(line, "go")) debug_stop = 0;
|
|
else if(!strcmp(line, "parent")) debug_parent = 1;
|
|
else printf("Unknown debug option : '%s'\n", line);
|
|
|
|
line = next;
|
|
}
|
|
return(0);
|
|
}
|
|
|
|
__uml_setup("debug", uml_debug_setup,
|
|
"debug\n"
|
|
" Starts up the kernel under the control of gdb. See the \n"
|
|
" kernel debugging tutorial and the debugging session pages\n"
|
|
" at http://user-mode-linux.sourceforge.net/ for more information.\n\n"
|
|
);
|
|
|
|
static int __init uml_debugtrace_setup(char *line, int *add)
|
|
{
|
|
debug_trace = 1;
|
|
return 0;
|
|
}
|
|
__uml_setup("debugtrace", uml_debugtrace_setup,
|
|
"debugtrace\n"
|
|
" Causes the tracing thread to pause until it is attached by a\n"
|
|
" debugger and continued. This is mostly for debugging crashes\n"
|
|
" early during boot, and should be pretty much obsoleted by\n"
|
|
" the debug switch.\n\n"
|
|
);
|
|
|
|
/*
|
|
* Overrides for Emacs so that we follow Linus's tabbing style.
|
|
* Emacs will notice this stuff at the end of the file and automatically
|
|
* adjust the settings for this buffer only. This must remain at the end
|
|
* of the file.
|
|
* ---------------------------------------------------------------------------
|
|
* Local variables:
|
|
* c-file-style: "linux"
|
|
* End:
|
|
*/
|