adlr@google.com | 3defe6a | 2009-12-04 20:57:17 +0000 | [diff] [blame^] | 1 | // Copyright (c) 2009 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include "update_engine/filesystem_iterator.h" |
| 6 | #include <sys/types.h> |
| 7 | #include <dirent.h> |
| 8 | #include <errno.h> |
| 9 | #include <set> |
| 10 | #include <string> |
| 11 | #include <vector> |
| 12 | #include "chromeos/obsolete_logging.h" |
| 13 | #include "update_engine/utils.h" |
| 14 | |
| 15 | using std::set; |
| 16 | using std::string; |
| 17 | using std::vector; |
| 18 | |
| 19 | namespace chromeos_update_engine { |
| 20 | |
| 21 | // We use a macro here for two reasons: |
| 22 | // 1. We want to be able to return from the caller's function. |
| 23 | // 2. We can use the #macro_arg ism to get a string of the calling statement, |
| 24 | // which we can log. |
| 25 | |
| 26 | #define RETURN_ERROR_IF_FALSE(_statement) \ |
| 27 | do { \ |
| 28 | bool _result = (_statement); \ |
| 29 | if (!_result) { \ |
| 30 | string _message = utils::ErrnoNumberAsString(errno); \ |
| 31 | LOG(INFO) << #_statement << " failed: " << _message << ". Aborting"; \ |
| 32 | is_end_ = true; \ |
| 33 | is_err_ = true; \ |
| 34 | return; \ |
| 35 | } \ |
| 36 | } while (0) |
| 37 | |
| 38 | FilesystemIterator::FilesystemIterator( |
| 39 | const std::string& path, |
| 40 | const std::set<std::string>& excl_prefixes) |
| 41 | : excl_prefixes_(excl_prefixes), |
| 42 | is_end_(false), |
| 43 | is_err_(false) { |
| 44 | root_path_ = utils::NormalizePath(path, true); |
| 45 | RETURN_ERROR_IF_FALSE(lstat(root_path_.c_str(), &stbuf_) == 0); |
| 46 | root_dev_ = stbuf_.st_dev; |
| 47 | } |
| 48 | |
| 49 | FilesystemIterator::~FilesystemIterator() { |
| 50 | for (vector<DIR*>::iterator it = dirs_.begin(); it != dirs_.end(); ++it) { |
| 51 | LOG_IF(ERROR, closedir(*it) != 0) << "closedir failed"; |
| 52 | } |
| 53 | } |
| 54 | |
| 55 | // Returns full path for current file |
| 56 | std::string FilesystemIterator::GetFullPath() const { |
| 57 | return root_path_ + GetPartialPath(); |
| 58 | } |
| 59 | |
| 60 | std::string FilesystemIterator::GetPartialPath() const { |
| 61 | std::string ret; |
| 62 | for (vector<string>::const_iterator it = names_.begin(); |
| 63 | it != names_.end(); ++it) { |
| 64 | ret += "/"; |
| 65 | ret += *it; |
| 66 | } |
| 67 | return ret; |
| 68 | } |
| 69 | |
| 70 | // Increments to the next file |
| 71 | void FilesystemIterator::Increment() { |
| 72 | // If we're currently on a dir, descend into children, but only if |
| 73 | // we're on the same device as the root device |
| 74 | |
| 75 | bool entering_dir = false; // true if we're entering into a new dir |
| 76 | if (S_ISDIR(stbuf_.st_mode) && (stbuf_.st_dev == root_dev_)) { |
| 77 | DIR* dir = opendir(GetFullPath().c_str()); |
| 78 | if ((!dir) && ((errno == ENOTDIR) || (errno == ENOENT))) { |
| 79 | // opendir failed b/c either it's not a dir or it doesn't exist. |
| 80 | // that's fine. let's just skip over this. |
| 81 | LOG(ERROR) << "Can't descend into " << GetFullPath(); |
| 82 | } else { |
| 83 | RETURN_ERROR_IF_FALSE(dir); |
| 84 | entering_dir = true; |
| 85 | dirs_.push_back(dir); |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | if (!entering_dir && names_.empty()) { |
| 90 | // root disappeared while we tried to descend into it |
| 91 | is_end_ = true; |
| 92 | return; |
| 93 | } |
| 94 | |
| 95 | if (!entering_dir) |
| 96 | names_.pop_back(); |
| 97 | |
| 98 | IncrementInternal(); |
| 99 | for (set<string>::const_iterator it = excl_prefixes_.begin(); |
| 100 | it != excl_prefixes_.end(); ++it) { |
| 101 | if (utils::StringHasPrefix(GetPartialPath(), *it)) { |
| 102 | Increment(); |
| 103 | break; |
| 104 | } |
| 105 | } |
| 106 | return; |
| 107 | } |
| 108 | |
| 109 | // Assumes that we need to find the next child of dirs_.back(), or if |
| 110 | // there are none more, go up the chain |
| 111 | void FilesystemIterator::IncrementInternal() { |
| 112 | CHECK_EQ(dirs_.size(), names_.size() + 1); |
| 113 | for (;;) { |
| 114 | struct dirent dir_entry; |
| 115 | struct dirent* dir_entry_pointer; |
| 116 | int r; |
| 117 | RETURN_ERROR_IF_FALSE( |
| 118 | (r = readdir_r(dirs_.back(), &dir_entry, &dir_entry_pointer)) == 0); |
| 119 | if (dir_entry_pointer) { |
| 120 | // Found an entry |
| 121 | names_.push_back(dir_entry_pointer->d_name); |
| 122 | // Validate |
| 123 | RETURN_ERROR_IF_FALSE(lstat(GetFullPath().c_str(), &stbuf_) == 0); |
| 124 | if (strcmp(dir_entry_pointer->d_name, ".") && |
| 125 | strcmp(dir_entry_pointer->d_name, "..")) { |
| 126 | // Done |
| 127 | return; |
| 128 | } |
| 129 | // Child didn't work out. Try again |
| 130 | names_.pop_back(); |
| 131 | } else { |
| 132 | // No more children in this dir. Pop it and try again |
| 133 | RETURN_ERROR_IF_FALSE(closedir(dirs_.back()) == 0); |
| 134 | dirs_.pop_back(); |
| 135 | if (dirs_.empty()) { |
| 136 | CHECK(names_.empty()); |
| 137 | // Done with the entire iteration |
| 138 | is_end_ = true; |
| 139 | return; |
| 140 | } |
| 141 | CHECK(!names_.empty()); |
| 142 | names_.pop_back(); |
| 143 | } |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | } // namespace chromeos_update_engine |