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// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "update_engine/filesystem_iterator.h"
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
#include <set>
#include <string>
#include <vector>
#include "chromeos/obsolete_logging.h"
#include "update_engine/utils.h"
using std::set;
using std::string;
using std::vector;
namespace chromeos_update_engine {
// We use a macro here for two reasons:
// 1. We want to be able to return from the caller's function.
// 2. We can use the #macro_arg ism to get a string of the calling statement,
// which we can log.
#define RETURN_ERROR_IF_FALSE(_statement) \
do { \
bool _result = (_statement); \
if (!_result) { \
string _message = utils::ErrnoNumberAsString(errno); \
LOG(INFO) << #_statement << " failed: " << _message << ". Aborting"; \
is_end_ = true; \
is_err_ = true; \
return; \
} \
} while (0)
FilesystemIterator::FilesystemIterator(
const std::string& path,
const std::set<std::string>& excl_prefixes)
: excl_prefixes_(excl_prefixes),
is_end_(false),
is_err_(false) {
root_path_ = utils::NormalizePath(path, true);
RETURN_ERROR_IF_FALSE(lstat(root_path_.c_str(), &stbuf_) == 0);
root_dev_ = stbuf_.st_dev;
}
FilesystemIterator::~FilesystemIterator() {
for (vector<DIR*>::iterator it = dirs_.begin(); it != dirs_.end(); ++it) {
LOG_IF(ERROR, closedir(*it) != 0) << "closedir failed";
}
}
// Returns full path for current file
std::string FilesystemIterator::GetFullPath() const {
return root_path_ + GetPartialPath();
}
std::string FilesystemIterator::GetPartialPath() const {
std::string ret;
for (vector<string>::const_iterator it = names_.begin();
it != names_.end(); ++it) {
ret += "/";
ret += *it;
}
return ret;
}
// Increments to the next file
void FilesystemIterator::Increment() {
// If we're currently on a dir, descend into children, but only if
// we're on the same device as the root device
bool entering_dir = false; // true if we're entering into a new dir
if (S_ISDIR(stbuf_.st_mode) && (stbuf_.st_dev == root_dev_)) {
DIR* dir = opendir(GetFullPath().c_str());
if ((!dir) && ((errno == ENOTDIR) || (errno == ENOENT))) {
// opendir failed b/c either it's not a dir or it doesn't exist.
// that's fine. let's just skip over this.
LOG(ERROR) << "Can't descend into " << GetFullPath();
} else {
RETURN_ERROR_IF_FALSE(dir);
entering_dir = true;
dirs_.push_back(dir);
}
}
if (!entering_dir && names_.empty()) {
// root disappeared while we tried to descend into it
is_end_ = true;
return;
}
if (!entering_dir)
names_.pop_back();
IncrementInternal();
for (set<string>::const_iterator it = excl_prefixes_.begin();
it != excl_prefixes_.end(); ++it) {
if (utils::StringHasPrefix(GetPartialPath(), *it)) {
Increment();
break;
}
}
return;
}
// Assumes that we need to find the next child of dirs_.back(), or if
// there are none more, go up the chain
void FilesystemIterator::IncrementInternal() {
CHECK_EQ(dirs_.size(), names_.size() + 1);
for (;;) {
struct dirent dir_entry;
struct dirent* dir_entry_pointer;
int r;
RETURN_ERROR_IF_FALSE(
(r = readdir_r(dirs_.back(), &dir_entry, &dir_entry_pointer)) == 0);
if (dir_entry_pointer) {
// Found an entry
names_.push_back(dir_entry_pointer->d_name);
// Validate
RETURN_ERROR_IF_FALSE(lstat(GetFullPath().c_str(), &stbuf_) == 0);
if (strcmp(dir_entry_pointer->d_name, ".") &&
strcmp(dir_entry_pointer->d_name, "..")) {
// Done
return;
}
// Child didn't work out. Try again
names_.pop_back();
} else {
// No more children in this dir. Pop it and try again
RETURN_ERROR_IF_FALSE(closedir(dirs_.back()) == 0);
dirs_.pop_back();
if (dirs_.empty()) {
CHECK(names_.empty());
// Done with the entire iteration
is_end_ = true;
return;
}
CHECK(!names_.empty());
names_.pop_back();
}
}
}
} // namespace chromeos_update_engine
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