tests/dd/tests_for_cleanup.c

#include "../../unity/unity.h"
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

/* The test file is included into dd.c, so we can directly access
   static globals/functions like cleanup, conversions_mask, interrupt_signal,
   and constants C_FSYNC/C_FDATASYNC. */

static int fd_is_closed(int fd)
{
    errno = 0;
    int flags = fcntl(fd, F_GETFL);
    return (flags == -1 && errno == EBADF);
}

static int save_stdio(int *saved_in, int *saved_out)
{
    *saved_in = dup(STDIN_FILENO);
    if (*saved_in < 0) return -1;
    *saved_out = dup(STDOUT_FILENO);
    if (*saved_out < 0) { close(*saved_in); return -1; }
    return 0;
}

static int restore_stdio(int saved_in, int saved_out)
{
    int ok = 0;
    if (saved_in >= 0) {
        if (dup2(saved_in, STDIN_FILENO) < 0) ok = -1;
        close(saved_in);
    }
    if (saved_out >= 0) {
        if (dup2(saved_out, STDOUT_FILENO) < 0) ok = -1;
        close(saved_out);
    }
    /* stdout FILE* still refers to fd=1; ensure stream is usable */
    clearerr(stdout);
    return ok;
}

static int redirect_stdout_to_temp(int *tmpfd_out)
{
    char tmpl[] = "/tmp/dd_cleanup_test_XXXXXX";
    int tfd = mkstemp(tmpl);
    if (tfd < 0)
        return -1;
    /* Unlink so the file is removed when all descriptors close */
    unlink(tmpl);
    if (dup2(tfd, STDOUT_FILENO) < 0) {
        close(tfd);
        return -1;
    }
    *tmpfd_out = tfd; /* Keep tfd open separately */
    return 0;
}

void setUp(void) {
    /* No global setup */
}

void tearDown(void) {
    /* No global teardown */
}

/* Test: When interrupted, cleanup should skip synchronize_output (i.e.,
   not clear C_FSYNC/C_FDATASYNC), and must close stdin/stdout. */
void test_cleanup_interrupted_skips_sync_and_closes(void)
{
    int saved_in = -1, saved_out = -1;
    TEST_ASSERT_EQUAL_INT(0, save_stdio(&saved_in, &saved_out));

    int old_mask = conversions_mask;
    sig_atomic_t old_intr = interrupt_signal;

    conversions_mask = C_FSYNC | C_FDATASYNC;
    interrupt_signal = SIGINT; /* Nonzero => skip synchronize_output */

    /* Call cleanup. Do not use Unity asserts until stdout is restored. */
    cleanup();

    int in_closed = fd_is_closed(STDIN_FILENO);
    int out_closed = fd_is_closed(STDOUT_FILENO);

    /* Restore stdio before asserting */
    TEST_ASSERT_EQUAL_INT(0, restore_stdio(saved_in, saved_out));
    saved_in = saved_out = -1;

    /* Assert that both stdio descriptors were closed */
    TEST_ASSERT_TRUE_MESSAGE(in_closed, "STDIN was not closed by cleanup when interrupted");
    TEST_ASSERT_TRUE_MESSAGE(out_closed, "STDOUT was not closed by cleanup when interrupted");

    /* Assert that sync bits remain set (synchronize_output not called) */
    TEST_ASSERT_TRUE_MESSAGE((conversions_mask & (C_FSYNC | C_FDATASYNC)) == (C_FSYNC | C_FDATASYNC),
                             "synchronize_output ran despite interrupt_signal; bits were cleared");

    /* Restore globals */
    conversions_mask = old_mask;
    interrupt_signal = old_intr;
}

/* Test: When not interrupted and stdout is a regular file, cleanup should
   call synchronize_output (which succeeds) and clear C_FSYNC/C_FDATASYNC,
   and close stdin/stdout. */
void test_cleanup_calls_sync_clears_bits_and_closes(void)
{
    int saved_in = -1, saved_out = -1;
    TEST_ASSERT_EQUAL_INT(0, save_stdio(&saved_in, &saved_out));

    int tmpfd = -1;
    TEST_ASSERT_EQUAL_INT_MESSAGE(0, redirect_stdout_to_temp(&tmpfd), "Failed to redirect stdout to temp file");

    int old_mask = conversions_mask;
    sig_atomic_t old_intr = interrupt_signal;

    conversions_mask = C_FDATASYNC; /* Will call fdatasync and possibly fsync */
    interrupt_signal = 0;           /* Not interrupted => synchronize_output runs */

    cleanup();

    int in_closed = fd_is_closed(STDIN_FILENO);
    int out_closed = fd_is_closed(STDOUT_FILENO);

    /* Restore stdio before asserting */
    TEST_ASSERT_EQUAL_INT(0, restore_stdio(saved_in, saved_out));
    saved_in = saved_out = -1;

    /* Close temp backing fd (cleanup closed fd 1; tfd still open) */
    if (tmpfd >= 0) close(tmpfd);

    TEST_ASSERT_TRUE_MESSAGE(in_closed, "STDIN was not closed by cleanup");
    TEST_ASSERT_TRUE_MESSAGE(out_closed, "STDOUT was not closed by cleanup");

    /* synchronize_output clears these bits even if it had to fall back to fsync */
    TEST_ASSERT_EQUAL_INT_MESSAGE(0, conversions_mask & (C_FSYNC | C_FDATASYNC),
                                  "synchronize_output did not clear sync bits");

    /* Restore globals */
    conversions_mask = old_mask;
    interrupt_signal = old_intr;
}

/* Test: When not interrupted and stdout is a pipe, synchronize_output fails
   (fsync on a pipe -> EINVAL), so cleanup must exit with failure. */
void test_cleanup_exit_on_sync_failure(void)
{
    fflush(stdout);
    fflush(stderr);
    pid_t pid = fork();
    TEST_ASSERT_MESSAGE(pid >= 0, "fork failed");

    if (pid == 0) {
        /* Child: set up stdout as a pipe's write end */
        int fds[2];
        if (pipe(fds) != 0) _exit(100);
        /* Redirect stdout to pipe write end */
        if (dup2(fds[1], STDOUT_FILENO) < 0) _exit(101);
        close(fds[0]);
        close(fds[1]);

        conversions_mask = C_FSYNC; /* Force fsync */
        interrupt_signal = 0;       /* Not interrupted */

        /* This should call synchronize_output, which fails, and then exit(EXIT_FAILURE). */
        cleanup();

        /* Should not reach here */
        _exit(77);
    } else {
        int status = 0;
        waitpid(pid, &status, 0);
        TEST_ASSERT_TRUE_MESSAGE(WIFEXITED(status), "Child did not exit normally");
        TEST_ASSERT_EQUAL_INT_MESSAGE(EXIT_FAILURE, WEXITSTATUS(status),
                                      "cleanup did not exit with failure on sync failure");
    }
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_cleanup_interrupted_skips_sync_and_closes);
    RUN_TEST(test_cleanup_calls_sync_clears_bits_and_closes);
    RUN_TEST(test_cleanup_exit_on_sync_failure);
    return UNITY_END();
}