// Copyright 2019 Roman Perepelitsa.
//
// This file is part of GitStatus.
//
// GitStatus is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GitStatus is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with GitStatus. If not, see <https://www.gnu.org/licenses/>.
#include "check_dir_mtime.h"
#include <fcntl.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#include <cerrno>
#include <cstring>
#include <ctime>
#include <string>
#include <vector>
#include "check.h"
#include "dir.h"
#include "logging.h"
#include "print.h"
#include "scope_guard.h"
#include "stat.h"
namespace gitstatus {
namespace {
constexpr char kDirPrefix[] = ".gitstatus.";
void Touch(const char* path) {
int fd = creat(path, 0444);
VERIFY(fd >= 0) << Errno();
CHECK(!close(fd)) << Errno();
}
bool StatChanged(const char* path, const struct stat& prev) {
struct stat cur;
VERIFY(!lstat(path, &cur)) << Errno();
return !StatEq(prev, cur);
}
void RemoveStaleDirs(const char* root_dir) {
int dir_fd = open(root_dir, O_DIRECTORY | O_CLOEXEC);
if (dir_fd < 0) return;
ON_SCOPE_EXIT(&) { CHECK(!close(dir_fd)) << Errno(); };
Arena arena;
std::vector<char*> entries;
const std::time_t now = std::time(nullptr);
if (!ListDir(dir_fd, arena, entries,
/* precompose_unicode = */ false,
/* case_sensitive = */ true)) {
return;
}
std::string path = root_dir;
const size_t root_dir_len = path.size();
for (const char* entry : entries) {
if (std::strlen(entry) < std::strlen(kDirPrefix)) continue;
if (std::memcmp(entry, kDirPrefix, std::strlen(kDirPrefix))) continue;
struct stat st;
if (fstatat(dir_fd, entry, &st, AT_SYMLINK_NOFOLLOW)) {
LOG(WARN) << "Cannot stat " << Print(entry) << " in " << Print(root_dir) << ": " << Errno();
continue;
}
if (MTim(st).tv_sec + 10 > now) continue;
path.resize(root_dir_len);
path += entry;
size_t dir_len = path.size();
path += "/b/1";
if (unlink(path.c_str()) && errno != ENOENT) {
LOG(WARN) << "Cannot unlink " << Print(path) << ": " << Errno();
continue;
}
for (const char* d : {"/a/1", "/a", "/b", ""}) {
path.resize(dir_len);
path += d;
if (rmdir(path.c_str()) && errno != ENOENT) {
LOG(WARN) << "Cannot remove " << Print(path) << ": " << Errno();
break;
}
}
}
}
} // namespace
bool CheckDirMtime(const char* root_dir) {
try {
RemoveStaleDirs(root_dir);
std::string tmp = std::string() + root_dir + kDirPrefix + "XXXXXX";
VERIFY(mkdtemp(&tmp[0])) << Errno();
ON_SCOPE_EXIT(&) { rmdir(tmp.c_str()); };
std::string a_dir = tmp + "/a";
VERIFY(!mkdir(a_dir.c_str(), 0755)) << Errno();
ON_SCOPE_EXIT(&) { rmdir(a_dir.c_str()); };
struct stat a_st;
VERIFY(!lstat(a_dir.c_str(), &a_st)) << Errno();
std::string b_dir = tmp + "/b";
VERIFY(!mkdir(b_dir.c_str(), 0755)) << Errno();
ON_SCOPE_EXIT(&) { rmdir(b_dir.c_str()); };
struct stat b_st;
VERIFY(!lstat(b_dir.c_str(), &b_st)) << Errno();
while (sleep(1)) {
// zzzz
}
std::string a1 = a_dir + "/1";
VERIFY(!mkdir(a1.c_str(), 0755)) << Errno();
ON_SCOPE_EXIT(&) { rmdir(a1.c_str()); };
if (!StatChanged(a_dir.c_str(), a_st)) {
LOG(WARN) << "Creating a directory doesn't change mtime of the parent: " << Print(root_dir);
return false;
}
std::string b1 = b_dir + "/1";
Touch(b1.c_str());
ON_SCOPE_EXIT(&) { unlink(b1.c_str()); };
if (!StatChanged(b_dir.c_str(), b_st)) {
LOG(WARN) << "Creating a file doesn't change mtime of the parent: " << Print(root_dir);
return false;
}
LOG(INFO) << "All mtime checks have passes. Enabling untracked cache: " << Print(root_dir);
return true;
} catch (const Exception&) {
LOG(WARN) << "Error while testing for mtime capability: " << Print(root_dir);
return false;
}
}
} // namespace gitstatus
