llvm/lib/Support/Unix/PathV2.inc
2010-12-03 07:41:25 +00:00

299 lines
8.6 KiB
C++

//===- llvm/Support/Unix/PathV2.cpp - Unix Path Implementation --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Unix specific implementation of the PathV2 API.
//
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only generic UNIX code that
//=== is guaranteed to work on *all* UNIX variants.
//===----------------------------------------------------------------------===//
#include "Unix.h"
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
#if HAVE_STDIO_H
#include <stdio.h>
#endif
using namespace llvm;
namespace {
struct AutoFD {
int FileDescriptor;
AutoFD(int fd) : FileDescriptor(fd) {}
~AutoFD() {
if (FileDescriptor >= 0)
::close(FileDescriptor);
}
int take() {
int ret = FileDescriptor;
FileDescriptor = -1;
return ret;
}
operator int() const {return FileDescriptor;}
};
error_code TempDir(SmallVectorImpl<char> &result) {
// FIXME: Don't use TMPDIR if program is SUID or SGID enabled.
const char *dir = 0;
(dir = std::getenv("TMPDIR" )) ||
(dir = std::getenv("TMP" )) ||
(dir = std::getenv("TEMP" )) ||
(dir = std::getenv("TEMPDIR")) ||
#ifdef P_tmpdir
(dir = P_tmpdir) ||
#endif
(dir = "/tmp");
result.set_size(0);
StringRef d(dir);
result.append(d.begin(), d.end());
return make_error_code(errc::success);
}
}
namespace llvm {
namespace sys {
namespace path {
error_code current_path(SmallVectorImpl<char> &result) {
long size = ::pathconf(".", _PC_PATH_MAX);
result.reserve(size + 1);
result.set_size(size + 1);
if (::getcwd(result.data(), result.size()) == 0)
return error_code(errno, system_category());
result.set_size(strlen(result.data()));
return make_error_code(errc::success);
}
} // end namespace path
namespace fs{
error_code copy_file(const Twine &from, const Twine &to, copy_option copt) {
// Get arguments.
SmallString<128> from_storage;
SmallString<128> to_storage;
StringRef f = from.toNullTerminatedStringRef(from_storage);
StringRef t = to.toNullTerminatedStringRef(to_storage);
const size_t buf_sz = 32768;
char buffer[buf_sz];
int from_file = -1, to_file = -1;
// Open from.
if ((from_file = ::open(f.begin(), O_RDONLY)) < 0)
return error_code(errno, system_category());
AutoFD from_fd(from_file);
// Stat from.
struct stat from_stat;
if (::stat(f.begin(), &from_stat) != 0)
return error_code(errno, system_category());
// Setup to flags.
int to_flags = O_CREAT | O_WRONLY;
if (copt == copy_option::fail_if_exists)
to_flags |= O_EXCL;
// Open to.
if ((to_file = ::open(t.begin(), to_flags, from_stat.st_mode)) < 0)
return error_code(errno, system_category());
AutoFD to_fd(to_file);
// Copy!
ssize_t sz, sz_read = 1, sz_write;
while (sz_read > 0 &&
(sz_read = ::read(from_fd, buffer, buf_sz)) > 0) {
// Allow for partial writes - see Advanced Unix Programming (2nd Ed.),
// Marc Rochkind, Addison-Wesley, 2004, page 94
sz_write = 0;
do {
if ((sz = ::write(to_fd, buffer + sz_write, sz_read - sz_write)) < 0) {
sz_read = sz; // cause read loop termination.
break; // error.
}
sz_write += sz;
} while (sz_write < sz_read);
}
// After all the file operations above the return value of close actually
// matters.
if (::close(from_fd.take()) < 0) sz_read = -1;
if (::close(to_fd.take()) < 0) sz_read = -1;
// Check for errors.
if (sz_read < 0)
return error_code(errno, system_category());
return make_error_code(errc::success);
}
error_code create_directory(const Twine &path, bool &existed) {
SmallString<128> path_storage;
StringRef p = path.toNullTerminatedStringRef(path_storage);
if (::mkdir(p.begin(), 0700) == -1) {
if (errno != EEXIST)
return error_code(errno, system_category());
existed = true;
} else
existed = false;
return make_error_code(errc::success);
}
error_code create_hard_link(const Twine &to, const Twine &from) {
// Get arguments.
SmallString<128> from_storage;
SmallString<128> to_storage;
StringRef f = from.toNullTerminatedStringRef(from_storage);
StringRef t = to.toNullTerminatedStringRef(to_storage);
if (::link(t.begin(), f.begin()) == -1)
return error_code(errno, system_category());
return make_error_code(errc::success);
}
error_code create_symlink(const Twine &to, const Twine &from) {
// Get arguments.
SmallString<128> from_storage;
SmallString<128> to_storage;
StringRef f = from.toNullTerminatedStringRef(from_storage);
StringRef t = to.toNullTerminatedStringRef(to_storage);
if (::symlink(t.begin(), f.begin()) == -1)
return error_code(errno, system_category());
return make_error_code(errc::success);
}
error_code exists(const Twine &path, bool &result) {
SmallString<128> path_storage;
StringRef p = path.toNullTerminatedStringRef(path_storage);
struct stat status;
if (::stat(p.begin(), &status) == -1) {
if (errno != ENOENT)
return error_code(errno, system_category());
result = false;
} else
result = true;
return make_error_code(errc::success);
}
error_code unique_file(const Twine &model, int &result_fd,
SmallVectorImpl<char> &result_path) {
SmallString<128> Model;
model.toVector(Model);
// Null terminate.
Model.c_str();
// Make model absolute by prepending a temp directory if it's not already.
bool absolute;
if (error_code ec = path::is_absolute(Twine(Model), absolute)) return ec;
if (!absolute) {
SmallString<128> TDir;
if (error_code ec = TempDir(TDir)) return ec;
if (error_code ec = path::append(TDir, Twine(Model))) return ec;
Model.swap(TDir);
}
// Replace '%' with random chars. From here on, DO NOT modify model. It may be
// needed if the randomly chosen path already exists.
SmallString<128> RandomPath;
RandomPath.reserve(Model.size() + 1);
::srand(::time(NULL));
retry_random_path:
// This is opened here instead of above to make it easier to track when to
// close it. Collisions should be rare enough for the possible extra syscalls
// not to matter.
FILE *RandomSource = ::fopen("/dev/urandom", "r");
RandomPath.set_size(0);
for (SmallVectorImpl<char>::const_iterator i = Model.begin(),
e = Model.end(); i != e; ++i) {
if (*i == '%') {
char val = 0;
if (RandomSource)
val = fgetc(RandomSource);
else
val = ::rand();
RandomPath.push_back("0123456789abcdef"[val & 15]);
} else
RandomPath.push_back(*i);
}
if (RandomSource)
::fclose(RandomSource);
// Try to open + create the file.
rety_open_create:
int RandomFD = ::open(RandomPath.c_str(), O_RDWR | O_CREAT | O_EXCL, 0600);
if (RandomFD == -1) {
// If the file existed, try again, otherwise, error.
if (errno == EEXIST)
goto retry_random_path;
// The path prefix doesn't exist.
if (errno == ENOENT) {
StringRef p(RandomPath.begin(), RandomPath.size());
SmallString<64> dir_to_create;
for (path::const_iterator i = path::begin(p),
e = --path::end(p); i != e; ++i) {
if (error_code ec = path::append(dir_to_create, *i)) return ec;
bool Exists;
if (error_code ec = exists(Twine(dir_to_create), Exists)) return ec;
if (!Exists) {
// Don't try to create network paths.
if (i->size() > 2 && (*i)[0] == '/' &&
(*i)[1] == '/' &&
(*i)[2] != '/')
return error_code(ENOENT, system_category());
if (::mkdir(dir_to_create.c_str(), 0700) == -1)
return error_code(errno, system_category());
}
}
goto rety_open_create;
}
return error_code(errno, system_category());
}
// Make the path absolute.
char real_path_buff[PATH_MAX + 1];
if (realpath(RandomPath.c_str(), real_path_buff) == NULL) {
::close(RandomFD);
::unlink(RandomPath.c_str());
return error_code(errno, system_category());
}
result_path.set_size(0);
StringRef d(real_path_buff);
result_path.append(d.begin(), d.end());
result_fd = RandomFD;
return make_error_code(errc::success);
}
} // end namespace fs
} // end namespace sys
} // end namespace llvm