blob: a3eddfe252fa2d6cb269cbcc7af730b7eaeb3e27 [file] [log] [blame]
/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "android-base/file.h"
#include <errno.h>
#include <fcntl.h>
#include <ftw.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <memory>
#include <mutex>
#include <string>
#include <vector>
#if defined(__APPLE__)
#include <mach-o/dyld.h>
#endif
#if defined(_WIN32)
#include <direct.h>
#include <windows.h>
#define O_NOFOLLOW 0
#define OS_PATH_SEPARATOR '\\'
#else
#define OS_PATH_SEPARATOR '/'
#endif
#include "android-base/macros.h" // For TEMP_FAILURE_RETRY on Darwin.
#include "android-base/unique_fd.h"
#include "android-base/utf8.h"
class FakeLog {
public:
FakeLog operator<<(const char*) { return *this; }
operator bool() { return false; }
};
#define PLOG(x) false && FakeLog()
namespace {
#ifdef _WIN32
static int mkstemp(char* name_template, size_t size_in_chars) {
std::wstring path;
CHECK(android::base::UTF8ToWide(name_template, &path))
<< "path can't be converted to wchar: " << name_template;
if (_wmktemp_s(path.data(), path.size() + 1) != 0) {
return -1;
}
// Use open() to match the close() that TemporaryFile's destructor does.
// Use O_BINARY to match base file APIs.
int fd = _wopen(path.c_str(), O_CREAT | O_EXCL | O_RDWR | O_BINARY, S_IRUSR | S_IWUSR);
if (fd < 0) {
return -1;
}
std::string path_utf8;
CHECK(android::base::WideToUTF8(path, &path_utf8)) << "path can't be converted to utf8";
CHECK(strcpy_s(name_template, size_in_chars, path_utf8.c_str()) == 0)
<< "utf8 path can't be assigned back to name_template";
return fd;
}
static char* mkdtemp(char* name_template, size_t size_in_chars) {
std::wstring path;
CHECK(android::base::UTF8ToWide(name_template, &path))
<< "path can't be converted to wchar: " << name_template;
if (_wmktemp_s(path.data(), path.size() + 1) != 0) {
return nullptr;
}
if (_wmkdir(path.c_str()) != 0) {
return nullptr;
}
std::string path_utf8;
CHECK(android::base::WideToUTF8(path, &path_utf8)) << "path can't be converted to utf8";
CHECK(strcpy_s(name_template, size_in_chars, path_utf8.c_str()) == 0)
<< "utf8 path can't be assigned back to name_template";
return name_template;
}
#endif
std::string GetSystemTempDir() {
#if defined(__ANDROID__)
const auto* tmpdir = getenv("TMPDIR");
if (tmpdir == nullptr) tmpdir = "/data/local/tmp";
if (access(tmpdir, R_OK | W_OK | X_OK) == 0) {
return tmpdir;
}
// Tests running in app context can't access /data/local/tmp,
// so try current directory if /data/local/tmp is not accessible.
return ".";
#elif defined(_WIN32)
wchar_t tmp_dir_w[MAX_PATH];
DWORD result = GetTempPathW(std::size(tmp_dir_w), tmp_dir_w); // checks TMP env
CHECK_NE(result, 0ul) << "GetTempPathW failed, error: " << GetLastError();
CHECK_LT(result, std::size(tmp_dir_w)) << "path truncated to: " << result;
// GetTempPath() returns a path with a trailing slash, but init()
// does not expect that, so remove it.
if (tmp_dir_w[result - 1] == L'\\') {
tmp_dir_w[result - 1] = L'\0';
}
std::string tmp_dir;
CHECK(android::base::WideToUTF8(tmp_dir_w, &tmp_dir)) << "path can't be converted to utf8";
return tmp_dir;
#else
const auto* tmpdir = getenv("TMPDIR");
if (tmpdir == nullptr) tmpdir = "/tmp";
return tmpdir;
#endif
}
} // namespace
TemporaryFile::TemporaryFile() {
init(GetSystemTempDir());
}
TemporaryFile::TemporaryFile(const std::string& tmp_dir) {
init(tmp_dir);
}
TemporaryFile::~TemporaryFile() {
if (fd != -1) {
close(fd);
}
if (remove_file_) {
unlink(path);
}
}
int TemporaryFile::release() {
int result = fd;
fd = -1;
return result;
}
void TemporaryFile::init(const std::string& tmp_dir) {
snprintf(path, sizeof(path), "%s%cTemporaryFile-XXXXXX", tmp_dir.c_str(), OS_PATH_SEPARATOR);
#if defined(_WIN32)
fd = mkstemp(path, sizeof(path));
#else
fd = mkstemp(path);
#endif
}
TemporaryDir::TemporaryDir() {
init(GetSystemTempDir());
}
TemporaryDir::~TemporaryDir() {
if (!remove_dir_and_contents_) return;
auto callback = [](const char* child, const struct stat*, int file_type, struct FTW*) -> int {
switch (file_type) {
case FTW_D:
case FTW_DP:
case FTW_DNR:
if (rmdir(child) == -1) {
PLOG(ERROR) << "rmdir " << child;
}
break;
case FTW_NS:
default:
if (rmdir(child) != -1) break;
// FALLTHRU (for gcc, lint, pcc, etc; and following for clang)
FALLTHROUGH_INTENDED;
case FTW_F:
case FTW_SL:
case FTW_SLN:
if (unlink(child) == -1) {
PLOG(ERROR) << "unlink " << child;
}
break;
}
return 0;
};
nftw(path, callback, 128, FTW_DEPTH | FTW_MOUNT | FTW_PHYS);
}
bool TemporaryDir::init(const std::string& tmp_dir) {
snprintf(path, sizeof(path), "%s%cTemporaryDir-XXXXXX", tmp_dir.c_str(), OS_PATH_SEPARATOR);
#if defined(_WIN32)
return (mkdtemp(path, sizeof(path)) != nullptr);
#else
return (mkdtemp(path) != nullptr);
#endif
}
namespace android {
namespace base {
// Versions of standard library APIs that support UTF-8 strings.
using namespace android::base::utf8;
bool ReadFdToString(borrowed_fd fd, std::string* content) {
content->clear();
// Although original we had small files in mind, this code gets used for
// very large files too, where the std::string growth heuristics might not
// be suitable. https://code.google.com/p/android/issues/detail?id=258500.
struct stat sb;
if (fstat(fd.get(), &sb) != -1 && sb.st_size > 0) {
content->reserve(sb.st_size);
}
char buf[BUFSIZ] __attribute__((__uninitialized__));
ssize_t n;
while ((n = TEMP_FAILURE_RETRY(read(fd.get(), &buf[0], sizeof(buf)))) > 0) {
content->append(buf, n);
}
return (n == 0) ? true : false;
}
bool ReadFileToString(const std::string& path, std::string* content, bool follow_symlinks) {
content->clear();
int flags = O_RDONLY | O_CLOEXEC | O_BINARY | (follow_symlinks ? 0 : O_NOFOLLOW);
android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(path.c_str(), flags)));
if (fd == -1) {
return false;
}
return ReadFdToString(fd, content);
}
bool WriteStringToFd(const std::string& content, borrowed_fd fd) {
const char* p = content.data();
size_t left = content.size();
while (left > 0) {
ssize_t n = TEMP_FAILURE_RETRY(write(fd.get(), p, left));
if (n == -1) {
return false;
}
p += n;
left -= n;
}
return true;
}
static bool CleanUpAfterFailedWrite(const std::string& path) {
// Something went wrong. Let's not leave a corrupt file lying around.
int saved_errno = errno;
unlink(path.c_str());
errno = saved_errno;
return false;
}
#if !defined(_WIN32)
bool WriteStringToFile(const std::string& content, const std::string& path,
mode_t mode, uid_t owner, gid_t group,
bool follow_symlinks) {
int flags = O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_BINARY |
(follow_symlinks ? 0 : O_NOFOLLOW);
android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(path.c_str(), flags, mode)));
if (fd == -1) {
PLOG(ERROR) << "android::WriteStringToFile open failed";
return false;
}
// We do an explicit fchmod here because we assume that the caller really
// meant what they said and doesn't want the umask-influenced mode.
if (fchmod(fd, mode) == -1) {
PLOG(ERROR) << "android::WriteStringToFile fchmod failed";
return CleanUpAfterFailedWrite(path);
}
if (fchown(fd, owner, group) == -1) {
PLOG(ERROR) << "android::WriteStringToFile fchown failed";
return CleanUpAfterFailedWrite(path);
}
if (!WriteStringToFd(content, fd)) {
PLOG(ERROR) << "android::WriteStringToFile write failed";
return CleanUpAfterFailedWrite(path);
}
return true;
}
#endif
bool WriteStringToFile(const std::string& content, const std::string& path,
bool follow_symlinks) {
int flags = O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_BINARY |
(follow_symlinks ? 0 : O_NOFOLLOW);
android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(path.c_str(), flags, 0666)));
if (fd == -1) {
return false;
}
return WriteStringToFd(content, fd) || CleanUpAfterFailedWrite(path);
}
bool ReadFully(borrowed_fd fd, void* data, size_t byte_count) {
uint8_t* p = reinterpret_cast<uint8_t*>(data);
size_t remaining = byte_count;
while (remaining > 0) {
ssize_t n = TEMP_FAILURE_RETRY(read(fd.get(), p, remaining));
if (n <= 0) return false;
p += n;
remaining -= n;
}
return true;
}
#if defined(_WIN32)
// Windows implementation of pread. Note that this DOES move the file descriptors read position,
// but it does so atomically.
static ssize_t pread(borrowed_fd fd, void* data, size_t byte_count, off64_t offset) {
DWORD bytes_read;
OVERLAPPED overlapped;
memset(&overlapped, 0, sizeof(OVERLAPPED));
overlapped.Offset = static_cast<DWORD>(offset);
overlapped.OffsetHigh = static_cast<DWORD>(offset >> 32);
if (!ReadFile(reinterpret_cast<HANDLE>(_get_osfhandle(fd.get())), data,
static_cast<DWORD>(byte_count), &bytes_read, &overlapped)) {
// In case someone tries to read errno (since this is masquerading as a POSIX call)
errno = EIO;
return -1;
}
return static_cast<ssize_t>(bytes_read);
}
#endif
bool ReadFullyAtOffset(borrowed_fd fd, void* data, size_t byte_count, off64_t offset) {
uint8_t* p = reinterpret_cast<uint8_t*>(data);
while (byte_count > 0) {
ssize_t n = TEMP_FAILURE_RETRY(pread(fd.get(), p, byte_count, offset));
if (n <= 0) return false;
p += n;
byte_count -= n;
offset += n;
}
return true;
}
bool WriteFully(borrowed_fd fd, const void* data, size_t byte_count) {
const uint8_t* p = reinterpret_cast<const uint8_t*>(data);
size_t remaining = byte_count;
while (remaining > 0) {
ssize_t n = TEMP_FAILURE_RETRY(write(fd.get(), p, remaining));
if (n == -1) return false;
p += n;
remaining -= n;
}
return true;
}
bool RemoveFileIfExists(const std::string& path, std::string* err) {
struct stat st;
#if defined(_WIN32)
// TODO: Windows version can't handle symbolic links correctly.
int result = stat(path.c_str(), &st);
bool file_type_removable = (result == 0 && S_ISREG(st.st_mode));
#else
int result = lstat(path.c_str(), &st);
bool file_type_removable = (result == 0 && (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)));
#endif
if (result == -1) {
if (errno == ENOENT || errno == ENOTDIR) return true;
if (err != nullptr) *err = strerror(errno);
return false;
}
if (result == 0) {
if (!file_type_removable) {
if (err != nullptr) {
*err = "is not a regular file or symbolic link";
}
return false;
}
if (unlink(path.c_str()) == -1) {
if (err != nullptr) {
*err = strerror(errno);
}
return false;
}
}
return true;
}
#if !defined(_WIN32)
bool Readlink(const std::string& path, std::string* result) {
result->clear();
// Most Linux file systems (ext2 and ext4, say) limit symbolic links to
// 4095 bytes. Since we'll copy out into the string anyway, it doesn't
// waste memory to just start there. We add 1 so that we can recognize
// whether it actually fit (rather than being truncated to 4095).
std::vector<char> buf(4095 + 1);
while (true) {
ssize_t size = readlink(path.c_str(), &buf[0], buf.size());
// Unrecoverable error?
if (size == -1) return false;
// It fit! (If size == buf.size(), it may have been truncated.)
if (static_cast<size_t>(size) < buf.size()) {
result->assign(&buf[0], size);
return true;
}
// Double our buffer and try again.
buf.resize(buf.size() * 2);
}
}
#endif
#if !defined(_WIN32)
bool Realpath(const std::string& path, std::string* result) {
result->clear();
// realpath may exit with EINTR. Retry if so.
char* realpath_buf = nullptr;
do {
realpath_buf = realpath(path.c_str(), nullptr);
} while (realpath_buf == nullptr && errno == EINTR);
if (realpath_buf == nullptr) {
return false;
}
result->assign(realpath_buf);
free(realpath_buf);
return true;
}
#endif
std::string GetExecutablePath() {
#if defined(__linux__)
std::string path;
android::base::Readlink("/proc/self/exe", &path);
return path;
#elif defined(__APPLE__)
char path[PATH_MAX + 1];
uint32_t path_len = sizeof(path);
int rc = _NSGetExecutablePath(path, &path_len);
if (rc < 0) {
std::unique_ptr<char> path_buf(new char[path_len]);
_NSGetExecutablePath(path_buf.get(), &path_len);
return path_buf.get();
}
return path;
#elif defined(_WIN32)
char path[PATH_MAX + 1];
DWORD result = GetModuleFileName(NULL, path, sizeof(path) - 1);
if (result == 0 || result == sizeof(path) - 1) return "";
path[PATH_MAX - 1] = 0;
return path;
#else
#error unknown OS
#endif
}
std::string GetExecutableDirectory() {
return Dirname(GetExecutablePath());
}
#if defined(_WIN32)
std::string Basename(const std::string& path) {
// TODO: how much of this is actually necessary for mingw?
// Copy path because basename may modify the string passed in.
std::string result(path);
// Use lock because basename() may write to a process global and return a
// pointer to that. Note that this locking strategy only works if all other
// callers to basename in the process also grab this same lock, but its
// better than nothing. Bionic's basename returns a thread-local buffer.
static std::mutex& basename_lock = *new std::mutex();
std::lock_guard<std::mutex> lock(basename_lock);
// Note that if std::string uses copy-on-write strings, &str[0] will cause
// the copy to be made, so there is no chance of us accidentally writing to
// the storage for 'path'.
char* name = basename(&result[0]);
// In case basename returned a pointer to a process global, copy that string
// before leaving the lock.
result.assign(name);
return result;
}
#else
// Copied from bionic so that Basename() below can be portable and thread-safe.
static int __basename_r(const char* path, char* buffer, size_t buffer_size) {
const char* startp = nullptr;
const char* endp = nullptr;
int len;
int result;
// Empty or NULL string gets treated as ".".
if (path == nullptr || *path == '\0') {
startp = ".";
len = 1;
goto Exit;
}
// Strip trailing slashes.
endp = path + strlen(path) - 1;
while (endp > path && *endp == '/') {
endp--;
}
// All slashes becomes "/".
if (endp == path && *endp == '/') {
startp = "/";
len = 1;
goto Exit;
}
// Find the start of the base.
startp = endp;
while (startp > path && *(startp - 1) != '/') {
startp--;
}
len = endp - startp +1;
Exit:
result = len;
if (buffer == nullptr) {
return result;
}
if (len > static_cast<int>(buffer_size) - 1) {
len = buffer_size - 1;
result = -1;
errno = ERANGE;
}
if (len >= 0) {
memcpy(buffer, startp, len);
buffer[len] = 0;
}
return result;
}
std::string Basename(const std::string& path) {
char buf[PATH_MAX];
__basename_r(path.c_str(), buf, sizeof(buf));
return buf;
}
#endif
#if defined(_WIN32)
std::string Dirname(const std::string& path) {
// TODO: how much of this is actually necessary for mingw?
// Copy path because dirname may modify the string passed in.
std::string result(path);
// Use lock because dirname() may write to a process global and return a
// pointer to that. Note that this locking strategy only works if all other
// callers to dirname in the process also grab this same lock, but its
// better than nothing. Bionic's dirname returns a thread-local buffer.
static std::mutex& dirname_lock = *new std::mutex();
std::lock_guard<std::mutex> lock(dirname_lock);
// Note that if std::string uses copy-on-write strings, &str[0] will cause
// the copy to be made, so there is no chance of us accidentally writing to
// the storage for 'path'.
char* parent = dirname(&result[0]);
// In case dirname returned a pointer to a process global, copy that string
// before leaving the lock.
result.assign(parent);
return result;
}
#else
// Copied from bionic so that Dirname() below can be portable and thread-safe.
static int __dirname_r(const char* path, char* buffer, size_t buffer_size) {
const char* endp = nullptr;
int len;
int result;
// Empty or NULL string gets treated as ".".
if (path == nullptr || *path == '\0') {
path = ".";
len = 1;
goto Exit;
}
// Strip trailing slashes.
endp = path + strlen(path) - 1;
while (endp > path && *endp == '/') {
endp--;
}
// Find the start of the dir.
while (endp > path && *endp != '/') {
endp--;
}
// Either the dir is "/" or there are no slashes.
if (endp == path) {
path = (*endp == '/') ? "/" : ".";
len = 1;
goto Exit;
}
do {
endp--;
} while (endp > path && *endp == '/');
len = endp - path + 1;
Exit:
result = len;
if (len + 1 > MAXPATHLEN) {
errno = ENAMETOOLONG;
return -1;
}
if (buffer == nullptr) {
return result;
}
if (len > static_cast<int>(buffer_size) - 1) {
len = buffer_size - 1;
result = -1;
errno = ERANGE;
}
if (len >= 0) {
memcpy(buffer, path, len);
buffer[len] = 0;
}
return result;
}
std::string Dirname(const std::string& path) {
char buf[PATH_MAX];
__dirname_r(path.c_str(), buf, sizeof(buf));
return buf;
}
#endif
} // namespace base
} // namespace android