[libc-commits] [libc] [libc] implement mkstemp (PR #199220)

[Michael Jones via libc-commits]

================
@@ -0,0 +1,182 @@
+//===-- Unittests for mkstemp ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "hdr/errno_macros.h"
+#include "hdr/fcntl_macros.h"
+#include "hdr/signal_macros.h"
+#include "src/stdlib/mkstemp.h"
+#include "src/string/strdup.h"
+#include "src/unistd/access.h"
+#include "src/unistd/close.h"
+#include "src/unistd/read.h"
+#include "src/unistd/unlink.h"
+#include "src/unistd/write.h"
+#include "test/UnitTest/ErrnoCheckingTest.h"
+#include "test/UnitTest/Test.h"
+
+using LlvmLibcMkstempTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;
+
+TEST_F(LlvmLibcMkstempTest, ValidTemplate) {
+  char *tmpl = LIBC_NAMESPACE::strdup(libc_make_test_file_path("tmp_XXXXXX"));
+  int fd = LIBC_NAMESPACE::mkstemp(tmpl);
+  ASSERT_GE(fd, 0);
+  LIBC_NAMESPACE::close(fd);
+  LIBC_NAMESPACE::unlink(tmpl);
+  ::free(tmpl);
+}
+
+TEST_F(LlvmLibcMkstempTest, TemplateModifiedInPlace) {
+  char *tmpl = LIBC_NAMESPACE::strdup(libc_make_test_file_path("tmp_XXXXXX"));
+  size_t len = 0;
+  while (tmpl[len] != '\0')
+    len++;
+  size_t count = 0;
+  for (size_t i = len; i > 0 && tmpl[i - 1] == 'X'; i--)
+    count++;
+  int fd = LIBC_NAMESPACE::mkstemp(tmpl);
+  ASSERT_GE(fd, 0);
+  bool modified = false;
+  for (size_t i = len - count; i < len; i++)
+    if (tmpl[i] != 'X') {
+      modified = true;
+      break;
+    }
+  EXPECT_TRUE(modified);
+  LIBC_NAMESPACE::close(fd);
+  LIBC_NAMESPACE::unlink(tmpl);
+  ::free(tmpl);
+}
+
+TEST_F(LlvmLibcMkstempTest, FileExists) {
+  char *tmpl = LIBC_NAMESPACE::strdup(libc_make_test_file_path("tmp_XXXXXX"));
+  int fd = LIBC_NAMESPACE::mkstemp(tmpl);
+  ASSERT_GE(fd, 0);
+  EXPECT_EQ(LIBC_NAMESPACE::access(tmpl, F_OK), 0);
+  LIBC_NAMESPACE::close(fd);
+  LIBC_NAMESPACE::unlink(tmpl);
+  ::free(tmpl);
+}
+
+TEST_F(LlvmLibcMkstempTest, FdIsWritable) {
+  char *tmpl = LIBC_NAMESPACE::strdup(libc_make_test_file_path("tmp_XXXXXX"));
+  int fd = LIBC_NAMESPACE::mkstemp(tmpl);
+  ASSERT_GE(fd, 0);
+  const char msg[] = "hello";
+  EXPECT_EQ(LIBC_NAMESPACE::write(fd, msg, 5), static_cast<ssize_t>(5));
+  LIBC_NAMESPACE::close(fd);
+  LIBC_NAMESPACE::unlink(tmpl);
+  ::free(tmpl);
+}
+
+TEST_F(LlvmLibcMkstempTest, Uniqueness) {
+  char *tmpl1 = LIBC_NAMESPACE::strdup(libc_make_test_file_path("tmp_XXXXXX"));
+  char *tmpl2 = LIBC_NAMESPACE::strdup(libc_make_test_file_path("tmp_XXXXXX"));
+  int fd1 = LIBC_NAMESPACE::mkstemp(tmpl1);
+  int fd2 = LIBC_NAMESPACE::mkstemp(tmpl2);
+  ASSERT_GE(fd1, 0);
+  ASSERT_GE(fd2, 0);
+  bool different = false;
+  for (size_t i = 0; tmpl1[i] != '\0'; i++)
+    if (tmpl1[i] != tmpl2[i]) {
+      different = true;
+      break;
+    }
+  EXPECT_TRUE(different);
+  LIBC_NAMESPACE::close(fd1);
+  LIBC_NAMESPACE::close(fd2);
+  LIBC_NAMESPACE::unlink(tmpl1);
+  LIBC_NAMESPACE::unlink(tmpl2);
+  ::free(tmpl1);
+  ::free(tmpl2);
+}
+
+TEST_F(LlvmLibcMkstempTest, FileIsEmpty) {
+  char *tmpl = LIBC_NAMESPACE::strdup(libc_make_test_file_path("tmp_XXXXXX"));
+  int fd = LIBC_NAMESPACE::mkstemp(tmpl);
+  ASSERT_GE(fd, 0);
+  // read should return 0 on empty file
+  char buf[1];
+  EXPECT_EQ(LIBC_NAMESPACE::read(fd, buf, 1), static_cast<ssize_t>(0));
+  LIBC_NAMESPACE::close(fd);
+  LIBC_NAMESPACE::unlink(tmpl);
+  ::free(tmpl);
+}
+
+TEST_F(LlvmLibcMkstempTest, SixXsNoPrefix) {
+  char *tmpl = LIBC_NAMESPACE::strdup(libc_make_test_file_path("XXXXXX"));
+  int fd = LIBC_NAMESPACE::mkstemp(tmpl);
+  ASSERT_GE(fd, 0);
+  LIBC_NAMESPACE::close(fd);
+  LIBC_NAMESPACE::unlink(tmpl);
+  ::free(tmpl);
+}
+
+TEST_F(LlvmLibcMkstempTest, MoreThanSixXs) {
+  char *tmpl =
+      LIBC_NAMESPACE::strdup(libc_make_test_file_path("tmp_XXXXXXXXXX"));
+  size_t len = 0;
+  while (tmpl[len] != '\0')
+    len++;
+  size_t count = 0;
+  for (size_t i = len; i > 0 && tmpl[i - 1] == 'X'; i--)
+    count++;
+  int fd = LIBC_NAMESPACE::mkstemp(tmpl);
+  ASSERT_GE(fd, 0);
+  bool modified = false;
+  for (size_t i = len - count; i < len; i++)
+    if (tmpl[i] != 'X') {
+      modified = true;
+      break;
+    }
+  EXPECT_TRUE(modified);
+  EXPECT_EQ(LIBC_NAMESPACE::access(tmpl, F_OK), 0);
+  LIBC_NAMESPACE::close(fd);
+  LIBC_NAMESPACE::unlink(tmpl);
+  ::free(tmpl);
+}
+
+#if defined(LIBC_ADD_NULL_CHECKS)
+TEST_F(LlvmLibcMkstempTest, NullPointer) {
+  EXPECT_DEATH([] { LIBC_NAMESPACE::mkstemp(nullptr); }, WITH_SIGNAL(-1));
+}
+#endif
+
+TEST_F(LlvmLibcMkstempTest, TemplateTooShort) {
+  char tmpl[] = "XXXXX";
+  int fd = LIBC_NAMESPACE::mkstemp(tmpl);
+  EXPECT_EQ(fd, -1);
+  ASSERT_ERRNO_EQ(EINVAL);
+}
+
+TEST_F(LlvmLibcMkstempTest, DoesNotEndInXs) {
+  char tmpl[] = "tmp_XXXXXY";
+  int fd = LIBC_NAMESPACE::mkstemp(tmpl);
+  EXPECT_EQ(fd, -1);
+  ASSERT_ERRNO_EQ(EINVAL);
+}
+
+TEST_F(LlvmLibcMkstempTest, XsInMiddleNotEnd) {
+  char tmpl[] = "XXXXXXtmp";
----------------
michaelrj-google wrote:

nit: The Xs here are at the beginning, not the middle.

https://github.com/llvm/llvm-project/pull/199220