1/* 2 * Copyright (C) 2016 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29#include "linker_logger.h" 30 31#include <string.h> 32#include <sys/prctl.h> 33#include <unistd.h> 34 35#include <string> 36#include <vector> 37 38#include "android-base/strings.h" 39#include "private/CachedProperty.h" 40#include "private/libc_logging.h" 41 42LinkerLogger g_linker_logger; 43bool g_greylist_disabled = false; 44 45static uint32_t ParseProperty(const std::string& value) { 46 if (value.empty()) { 47 return 0; 48 } 49 50 std::vector<std::string> options = android::base::Split(value, ","); 51 52 uint32_t flags = 0; 53 54 for (const auto& o : options) { 55 if (o == "dlerror") { 56 flags |= kLogErrors; 57 } else if (o == "dlopen") { 58 flags |= kLogDlopen; 59 } else if (o == "dlsym") { 60 flags |= kLogDlsym; 61 } else { 62 __libc_format_log(ANDROID_LOG_WARN, "linker", "Ignoring unknown debug.ld option \"%s\"", 63 o.c_str()); 64 } 65 } 66 67 return flags; 68} 69 70static void GetAppSpecificProperty(char* buffer) { 71 // Get process basename. 72 const char* process_name_start = basename(g_argv[0]); 73 74 // Remove ':' and everything after it. This is the naming convention for 75 // services: https://developer.android.com/guide/components/services.html 76 const char* process_name_end = strchr(process_name_start, ':'); 77 78 std::string process_name = (process_name_end != nullptr) ? 79 std::string(process_name_start, (process_name_end - process_name_start)) : 80 std::string(process_name_start); 81 82 std::string property_name = std::string("debug.ld.app.") + process_name; 83 __system_property_get(property_name.c_str(), buffer); 84} 85 86void LinkerLogger::ResetState() { 87 // The most likely scenario app is not debuggable and 88 // is running on a user build, in which case logging is disabled. 89 if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0) { 90 return; 91 } 92 93 // This is a convenient place to check whether the greylist should be disabled for testing. 94 static CachedProperty greylist_disabled("debug.ld.greylist_disabled"); 95 bool old_value = g_greylist_disabled; 96 g_greylist_disabled = (strcmp(greylist_disabled.Get(), "true") == 0); 97 if (g_greylist_disabled != old_value) { 98 __libc_format_log(ANDROID_LOG_INFO, "linker", "%s greylist", 99 g_greylist_disabled ? "Disabling" : "Enabling"); 100 } 101 102 flags_ = 0; 103 104 // For logging, check the flag applied to all processes first. 105 static CachedProperty debug_ld_all("debug.ld.all"); 106 flags_ |= ParseProperty(debug_ld_all.Get()); 107 108 // Ignore processes started without argv (http://b/33276926). 109 if (g_argv[0] == nullptr) { 110 return; 111 } 112 113 // Otherwise check the app-specific property too. 114 // We can't easily cache the property here because argv[0] changes. 115 char debug_ld_app[PROP_VALUE_MAX] = {}; 116 GetAppSpecificProperty(debug_ld_app); 117 flags_ |= ParseProperty(debug_ld_app); 118} 119 120void LinkerLogger::Log(uint32_t type, const char* format, ...) { 121 if ((flags_ & type) == 0) { 122 return; 123 } 124 125 va_list ap; 126 va_start(ap, format); 127 __libc_format_log_va_list(ANDROID_LOG_DEBUG, "linker", format, ap); 128 va_end(ap); 129} 130