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