Support/FileSystem: Add unique_file and exists implementations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120776 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Unix/PathV2.inc b/lib/Support/Unix/PathV2.inc
index 0fa4b87..1368a82 100644
--- a/lib/Support/Unix/PathV2.inc
+++ b/lib/Support/Unix/PathV2.inc
@@ -23,10 +23,12 @@
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
-#if HAVE_SYS_TYPES_H
-#include <sys/types.h>
+#if HAVE_STDIO_H
+#include <stdio.h>
#endif
+using namespace llvm;
+
namespace {
struct AutoFD {
int FileDescriptor;
@@ -45,6 +47,24 @@
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 {
@@ -126,6 +146,113 @@
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