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| 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 |
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