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/* Copyright (c) 2020, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/base.h>
#include "fork_detect.h"
// TSAN cannot cope with this test and complains that "starting new threads
// after multi-threaded fork is not supported".
#if defined(OPENSSL_FORK_DETECTION) && !defined(OPENSSL_TSAN) && \
!defined(OPENSSL_IOS)
#include <errno.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>
#include <functional>
#if defined(OPENSSL_THREADS)
#include <thread>
#include <vector>
#endif
#include <gtest/gtest.h>
static pid_t WaitpidEINTR(pid_t pid, int *out_status, int options) {
pid_t ret;
do {
ret = waitpid(pid, out_status, options);
} while (ret < 0 && errno == EINTR);
return ret;
}
// The *InChild functions run inside a child process and must report errors via
// |stderr| and |_exit| rather than GTest.
static void CheckGenerationAtLeastInChild(const char *name,
uint64_t minimum_expected) {
uint64_t generation = CRYPTO_get_fork_generation();
if (generation < minimum_expected) {
fprintf(stderr, "%s generation (#1) was %" PRIu64 ", wanted %" PRIu64 ".\n",
name, generation, minimum_expected);
_exit(1);
}
// The generation should be stable.
uint64_t new_generation = CRYPTO_get_fork_generation();
if (new_generation != generation) {
fprintf(stderr, "%s generation (#2) was %" PRIu64 ", wanted %" PRIu64 ".\n",
name, new_generation, generation);
_exit(1);
}
}
// ForkInChild forks a child which runs |f|. If the child exits unsuccessfully,
// this function will also exit unsuccessfully.
static void ForkInChild(std::function<void()> f) {
fflush(stderr); // Avoid duplicating any buffered output.
const pid_t pid = fork();
if (pid < 0) {
perror("fork");
_exit(1);
} else if (pid == 0) {
f();
_exit(0);
}
// Wait for the child and pass its exit code up.
int status;
if (WaitpidEINTR(pid, &status, 0) < 0) {
perror("waitpid");
_exit(1);
}
if (!WIFEXITED(status)) {
fprintf(stderr, "Child did not exit cleanly.\n");
_exit(1);
}
if (WEXITSTATUS(status) != 0) {
// Pass the failure up.
_exit(WEXITSTATUS(status));
}
}
TEST(ForkDetect, Test) {
uint64_t start = CRYPTO_get_fork_generation();
if (start == 0) {
GTEST_SKIP() << "Fork detection not supported. Skipping test.\n";
}
// The fork generation should be stable.
EXPECT_EQ(start, CRYPTO_get_fork_generation());
fflush(stderr);
const pid_t child = fork();
if (child == 0) {
// Fork grandchildren before observing the fork generation. The
// grandchildren will observe |start| + 1.
for (int i = 0; i < 2; i++) {
ForkInChild(
[&] { CheckGenerationAtLeastInChild("Grandchild", start + 1); });
}
// Now the child also observes |start| + 1. This is fine because it has
// already diverged from the grandchild at this point.
CheckGenerationAtLeastInChild("Child", start + 1);
// In the pthread_atfork the value may have changed.
uint64_t child_generation = CRYPTO_get_fork_generation();
// Forked grandchildren will now observe |start| + 2.
for (int i = 0; i < 2; i++) {
ForkInChild([&] {
CheckGenerationAtLeastInChild("Grandchild", child_generation + 1);
});
}
#if defined(OPENSSL_THREADS)
// The fork generation logic itself must be thread-safe. We test this in a
// child process to capture the actual fork detection. This segment is meant
// to be tested in TSan.
ForkInChild([&] {
std::vector<std::thread> threads(4);
for (int i = 0; i < 2; i++) {
for (auto &t : threads) {
t = std::thread([&] {
CheckGenerationAtLeastInChild("Grandchild thread",
child_generation + 1);
});
}
for (auto &t : threads) {
t.join();
}
}
});
#endif // OPENSSL_THREADS
// The child's observed value should be unchanged.
if (child_generation != CRYPTO_get_fork_generation()) {
fprintf(stderr,
"Child generation (final stable check) was %" PRIu64
", wanted %" PRIu64 ".\n",
child_generation, CRYPTO_get_fork_generation());
_exit(1);
}
_exit(0);
}
ASSERT_GT(child, 0) << "Error in fork: " << strerror(errno);
int status;
ASSERT_EQ(child, WaitpidEINTR(child, &status, 0))
<< "Error in waitpid: " << strerror(errno);
ASSERT_TRUE(WIFEXITED(status));
EXPECT_EQ(0, WEXITSTATUS(status)) << "Error in child process";
// We still observe |start|.
EXPECT_EQ(start, CRYPTO_get_fork_generation());
}
#endif // OPENSSL_FORK_DETECTION && !OPENSSL_TSAN && !OPENSSL_IOS
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