adb_utils.cpp revision a1071c6924654de89e077f50f47271bc3e08c569
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#define TRACE_TAG ADB 18 19#include "adb_utils.h" 20 21#include <libgen.h> 22#include <stdlib.h> 23#include <sys/stat.h> 24#include <sys/types.h> 25#include <unistd.h> 26 27#include <algorithm> 28 29#include <android-base/logging.h> 30#include <android-base/stringprintf.h> 31#include <android-base/strings.h> 32 33#include "adb.h" 34#include "adb_trace.h" 35#include "sysdeps.h" 36 37ADB_MUTEX_DEFINE(basename_lock); 38ADB_MUTEX_DEFINE(dirname_lock); 39 40#if defined(_WIN32) 41constexpr char kNullFileName[] = "NUL"; 42#else 43constexpr char kNullFileName[] = "/dev/null"; 44#endif 45 46void close_stdin() { 47 int fd = unix_open(kNullFileName, O_RDONLY); 48 if (fd == -1) { 49 fatal_errno("failed to open %s", kNullFileName); 50 } 51 52 if (TEMP_FAILURE_RETRY(dup2(fd, STDIN_FILENO)) == -1) { 53 fatal_errno("failed to redirect stdin to %s", kNullFileName); 54 } 55 unix_close(fd); 56} 57 58bool getcwd(std::string* s) { 59 char* cwd = getcwd(nullptr, 0); 60 if (cwd != nullptr) *s = cwd; 61 free(cwd); 62 return (cwd != nullptr); 63} 64 65bool directory_exists(const std::string& path) { 66 struct stat sb; 67 return lstat(path.c_str(), &sb) != -1 && S_ISDIR(sb.st_mode); 68} 69 70std::string escape_arg(const std::string& s) { 71 std::string result = s; 72 73 // Escape any ' in the string (before we single-quote the whole thing). 74 // The correct way to do this for the shell is to replace ' with '\'' --- that is, 75 // close the existing single-quoted string, escape a single single-quote, and start 76 // a new single-quoted string. Like the C preprocessor, the shell will concatenate 77 // these pieces into one string. 78 for (size_t i = 0; i < s.size(); ++i) { 79 if (s[i] == '\'') { 80 result.insert(i, "'\\'"); 81 i += 2; 82 } 83 } 84 85 // Prefix and suffix the whole string with '. 86 result.insert(result.begin(), '\''); 87 result.push_back('\''); 88 return result; 89} 90 91std::string adb_basename(const std::string& path) { 92 // Copy path because basename may modify the string passed in. 93 std::string result(path); 94 95 // Use lock because basename() may write to a process global and return a 96 // pointer to that. Note that this locking strategy only works if all other 97 // callers to dirname in the process also grab this same lock. 98 adb_mutex_lock(&basename_lock); 99 100 // Note that if std::string uses copy-on-write strings, &str[0] will cause 101 // the copy to be made, so there is no chance of us accidentally writing to 102 // the storage for 'path'. 103 char* name = basename(&result[0]); 104 105 // In case dirname returned a pointer to a process global, copy that string 106 // before leaving the lock. 107 result.assign(name); 108 109 adb_mutex_unlock(&basename_lock); 110 111 return result; 112} 113 114std::string adb_dirname(const std::string& path) { 115 // Copy path because dirname may modify the string passed in. 116 std::string result(path); 117 118 // Use lock because dirname() may write to a process global and return a 119 // pointer to that. Note that this locking strategy only works if all other 120 // callers to dirname in the process also grab this same lock. 121 adb_mutex_lock(&dirname_lock); 122 123 // Note that if std::string uses copy-on-write strings, &str[0] will cause 124 // the copy to be made, so there is no chance of us accidentally writing to 125 // the storage for 'path'. 126 char* parent = dirname(&result[0]); 127 128 // In case dirname returned a pointer to a process global, copy that string 129 // before leaving the lock. 130 result.assign(parent); 131 132 adb_mutex_unlock(&dirname_lock); 133 134 return result; 135} 136 137// Given a relative or absolute filepath, create the directory hierarchy 138// as needed. Returns true if the hierarchy is/was setup. 139bool mkdirs(const std::string& path) { 140 // TODO: all the callers do unlink && mkdirs && adb_creat --- 141 // that's probably the operation we should expose. 142 143 // Implementation Notes: 144 // 145 // Pros: 146 // - Uses dirname, so does not need to deal with OS_PATH_SEPARATOR. 147 // - On Windows, uses mingw dirname which accepts '/' and '\\', drive letters 148 // (C:\foo), UNC paths (\\server\share\dir\dir\file), and Unicode (when 149 // combined with our adb_mkdir() which takes UTF-8). 150 // - Is optimistic wrt thinking that a deep directory hierarchy will exist. 151 // So it does as few stat()s as possible before doing mkdir()s. 152 // Cons: 153 // - Recursive, so it uses stack space relative to number of directory 154 // components. 155 156 if (directory_exists(path)) { 157 return true; 158 } 159 160 const std::string parent(adb_dirname(path)); 161 162 // If dirname returned the same path as what we passed in, don't go recursive. 163 // This can happen on Windows when walking up the directory hierarchy and not 164 // finding anything that already exists (unlike POSIX that will eventually 165 // find . or /). 166 if (parent == path) { 167 errno = ENOENT; 168 return false; 169 } 170 171 // Recursively make parent directories of 'path'. 172 if (!mkdirs(parent)) { 173 return false; 174 } 175 176 // Now that the parent directory hierarchy of 'path' has been ensured, 177 // create path itself. 178 if (adb_mkdir(path, 0775) == -1) { 179 const int saved_errno = errno; 180 // If someone else created the directory, that is ok. 181 if (directory_exists(path)) { 182 return true; 183 } 184 // There might be a pre-existing file at 'path', or there might have been some other error. 185 errno = saved_errno; 186 return false; 187 } 188 189 return true; 190} 191 192std::string dump_hex(const void* data, size_t byte_count) { 193 byte_count = std::min(byte_count, size_t(16)); 194 195 const uint8_t* p = reinterpret_cast<const uint8_t*>(data); 196 197 std::string line; 198 for (size_t i = 0; i < byte_count; ++i) { 199 android::base::StringAppendF(&line, "%02x", p[i]); 200 } 201 line.push_back(' '); 202 203 for (size_t i = 0; i < byte_count; ++i) { 204 int ch = p[i]; 205 line.push_back(isprint(ch) ? ch : '.'); 206 } 207 208 return line; 209} 210 211std::string perror_str(const char* msg) { 212 return android::base::StringPrintf("%s: %s", msg, strerror(errno)); 213} 214 215#if !defined(_WIN32) 216bool set_file_block_mode(int fd, bool block) { 217 int flags = fcntl(fd, F_GETFL, 0); 218 if (flags == -1) { 219 PLOG(ERROR) << "failed to fcntl(F_GETFL) for fd " << fd; 220 return false; 221 } 222 flags = block ? (flags & ~O_NONBLOCK) : (flags | O_NONBLOCK); 223 if (fcntl(fd, F_SETFL, flags) != 0) { 224 PLOG(ERROR) << "failed to fcntl(F_SETFL) for fd " << fd << ", flags " << flags; 225 return false; 226 } 227 return true; 228} 229#endif 230