1.1 --- a/agent/src/os/linux/ps_proc.c Wed Feb 13 11:23:46 2013 +0100 1.2 +++ b/agent/src/os/linux/ps_proc.c Wed Feb 13 09:46:19 2013 +0100 1.3 @@ -1,5 +1,5 @@ 1.4 /* 1.5 - * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved. 1.6 + * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved. 1.7 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 1.8 * 1.9 * This code is free software; you can redistribute it and/or modify it 1.10 @@ -25,6 +25,7 @@ 1.11 #include <stdio.h> 1.12 #include <stdlib.h> 1.13 #include <string.h> 1.14 +#include <signal.h> 1.15 #include <errno.h> 1.16 #include <sys/ptrace.h> 1.17 #include "libproc_impl.h" 1.18 @@ -142,46 +143,71 @@ 1.19 1.20 } 1.21 1.22 +static bool ptrace_continue(pid_t pid, int signal) { 1.23 + // pass the signal to the process so we don't swallow it 1.24 + if (ptrace(PTRACE_CONT, pid, NULL, signal) < 0) { 1.25 + print_debug("ptrace(PTRACE_CONT, ..) failed for %d\n", pid); 1.26 + return false; 1.27 + } 1.28 + return true; 1.29 +} 1.30 + 1.31 +// waits until the ATTACH has stopped the process 1.32 +// by signal SIGSTOP 1.33 +static bool ptrace_waitpid(pid_t pid) { 1.34 + int ret; 1.35 + int status; 1.36 + while (true) { 1.37 + // Wait for debuggee to stop. 1.38 + ret = waitpid(pid, &status, 0); 1.39 + if (ret == -1 && errno == ECHILD) { 1.40 + // try cloned process. 1.41 + ret = waitpid(pid, &status, __WALL); 1.42 + } 1.43 + if (ret >= 0) { 1.44 + if (WIFSTOPPED(status)) { 1.45 + // Any signal will stop the thread, make sure it is SIGSTOP. Otherwise SIGSTOP 1.46 + // will still be pending and delivered when the process is DETACHED and the process 1.47 + // will go to sleep. 1.48 + if (WSTOPSIG(status) == SIGSTOP) { 1.49 + // Debuggee stopped by SIGSTOP. 1.50 + return true; 1.51 + } 1.52 + if (!ptrace_continue(pid, WSTOPSIG(status))) { 1.53 + print_error("Failed to correctly attach to VM. VM might HANG! [PTRACE_CONT failed, stopped by %d]\n", WSTOPSIG(status)); 1.54 + return false; 1.55 + } 1.56 + } else { 1.57 + print_debug("waitpid(): Child process exited/terminated (status = 0x%x)\n", status); 1.58 + return false; 1.59 + } 1.60 + } else { 1.61 + switch (errno) { 1.62 + case EINTR: 1.63 + continue; 1.64 + break; 1.65 + case ECHILD: 1.66 + print_debug("waitpid() failed. Child process pid (%d) does not exist \n", pid); 1.67 + break; 1.68 + case EINVAL: 1.69 + print_debug("waitpid() failed. Invalid options argument.\n"); 1.70 + break; 1.71 + default: 1.72 + print_debug("waitpid() failed. Unexpected error %d\n",errno); 1.73 + break; 1.74 + } 1.75 + return false; 1.76 + } 1.77 + } 1.78 +} 1.79 + 1.80 // attach to a process/thread specified by "pid" 1.81 static bool ptrace_attach(pid_t pid) { 1.82 if (ptrace(PTRACE_ATTACH, pid, NULL, NULL) < 0) { 1.83 print_debug("ptrace(PTRACE_ATTACH, ..) failed for %d\n", pid); 1.84 return false; 1.85 } else { 1.86 - int ret; 1.87 - int status; 1.88 - do { 1.89 - // Wait for debuggee to stop. 1.90 - ret = waitpid(pid, &status, 0); 1.91 - if (ret == -1 && errno == ECHILD) { 1.92 - // try cloned process. 1.93 - ret = waitpid(pid, &status, __WALL); 1.94 - } 1.95 - if (ret >= 0) { 1.96 - if (WIFSTOPPED(status)) { 1.97 - // Debuggee stopped. 1.98 - return true; 1.99 - } else { 1.100 - print_debug("waitpid(): Child process exited/terminated (status = 0x%x)\n", status); 1.101 - return false; 1.102 - } 1.103 - } else { 1.104 - switch (errno) { 1.105 - case EINTR: 1.106 - continue; 1.107 - break; 1.108 - case ECHILD: 1.109 - print_debug("waitpid() failed. Child process pid (%d) does not exist \n", pid); 1.110 - break; 1.111 - case EINVAL: 1.112 - print_debug("waitpid() failed. Invalid options argument.\n"); 1.113 - break; 1.114 - default: 1.115 - print_debug("waitpid() failed. Unexpected error %d\n",errno); 1.116 - } 1.117 - return false; 1.118 - } 1.119 - } while(true); 1.120 + return ptrace_waitpid(pid); 1.121 } 1.122 } 1.123