1/* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "diagnose_usb.h" 18 19#include <errno.h> 20#include <unistd.h> 21 22#include <string> 23 24#include <android-base/stringprintf.h> 25 26#if defined(__linux__) 27#include <grp.h> 28#include <pwd.h> 29#endif 30 31static const char kPermissionsHelpUrl[] = "http://developer.android.com/tools/device.html"; 32 33// Returns a message describing any potential problems we find with udev, or an empty string if we 34// can't find plugdev information (i.e. udev is not installed). 35static std::string GetUdevProblem() { 36#if defined(__linux__) 37 errno = 0; 38 group* plugdev_group = getgrnam("plugdev"); 39 40 if (plugdev_group == nullptr) { 41 if (errno != 0) { 42 perror("failed to read plugdev group info"); 43 } 44 // We can't give any generally useful advice here, just let the caller print the help URL. 45 return ""; 46 } 47 48 // getgroups(2) indicates that the GNU group_member(3) may not check the egid so we check it 49 // additionally just to be sure. 50 if (group_member(plugdev_group->gr_gid) || getegid() == plugdev_group->gr_gid) { 51 // The user is in plugdev so the problem is likely with the udev rules. 52 return "user in plugdev group; are your udev rules wrong?"; 53 } 54 passwd* pwd = getpwuid(getuid()); 55 return android::base::StringPrintf("user %s is not in the plugdev group", 56 pwd ? pwd->pw_name : "?"); 57#else 58 return ""; 59#endif 60} 61 62// Short help text must be a single line, and will look something like: 63// 64// no permissions (reason); see [URL] 65std::string UsbNoPermissionsShortHelpText() { 66 std::string help_text = "no permissions"; 67 68 std::string problem(GetUdevProblem()); 69 if (!problem.empty()) help_text += " (" + problem + ")"; 70 71 return android::base::StringPrintf("%s; see [%s]", help_text.c_str(), kPermissionsHelpUrl); 72} 73 74// Long help text can span multiple lines but doesn't currently provide more detailed information: 75// 76// insufficient permissions for device: reason 77// See [URL] for more information 78std::string UsbNoPermissionsLongHelpText() { 79 std::string header = "insufficient permissions for device"; 80 81 std::string problem(GetUdevProblem()); 82 if (!problem.empty()) header += ": " + problem; 83 84 return android::base::StringPrintf("%s\nSee [%s] for more information", header.c_str(), 85 kPermissionsHelpUrl); 86} 87