system/utest/fs/test-fcntl.cpp

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <fcntl.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>

#include <zircon/syscalls.h>
#include <unittest/unittest.h>

#include "filesystems.h"

bool TestFcntlAppend(void) {
    BEGIN_TEST;

    int fd = open("::file", O_APPEND | O_RDWR | O_CREAT, 0644);
    ASSERT_GT(fd, 0);

    // Do a quick check that O_APPEND is appending
    char buf[5];
    memset(buf, 'a', sizeof(buf));
    ASSERT_EQ(lseek(fd, 0, SEEK_SET), 0);
    ASSERT_EQ(write(fd, buf, sizeof(buf)), sizeof(buf));
    ASSERT_EQ(lseek(fd, 0, SEEK_SET), 0);
    ASSERT_EQ(write(fd, buf, sizeof(buf)), sizeof(buf));
    struct stat sb;
    ASSERT_EQ(fstat(fd, &sb), 0);
    ASSERT_EQ(sb.st_size, sizeof(buf) * 2);

    // Use F_GETFL; observe O_APPEND
    int flags = fcntl(fd, F_GETFL);
    ASSERT_GT(flags, -1, "Fcntl failed");
    ASSERT_EQ(flags & O_ACCMODE, O_RDWR, "Access mode flags did not match");
    ASSERT_EQ(flags & ~O_ACCMODE, O_APPEND, "Status flags did not match");

    // Use F_SETFL; turn off O_APPEND
    ASSERT_EQ(fcntl(fd, F_SETFL, flags & ~O_APPEND), 0, "Fcntl failed");

    // Use F_GETFL; observe O_APPEND has been turned off
    flags = fcntl(fd, F_GETFL);
    ASSERT_GT(flags, -1, "Fcntl failed");
    ASSERT_EQ(flags & O_ACCMODE, O_RDWR, "Access mode flags did not match");
    ASSERT_EQ(flags & ~O_ACCMODE, 0, "Status flags did not match");

    // Write to the file, verify it is no longer appending.
    ASSERT_EQ(lseek(fd, 0, SEEK_SET), 0);
    ASSERT_EQ(write(fd, buf, sizeof(buf)), sizeof(buf));
    ASSERT_EQ(fstat(fd, &sb), 0);
    ASSERT_EQ(sb.st_size, sizeof(buf) * 2);

    // Clean up
    ASSERT_EQ(close(fd), 0);
    ASSERT_EQ(unlink("::file"), 0);
    END_TEST;
}

bool TestFcntlAccessBits(void) {
    BEGIN_TEST;

    int fd = open("::file", O_APPEND | O_RDWR | O_CREAT, 0644);
    ASSERT_GT(fd, 0);

    // Do a quick check that we can write
    char buf[5];
    memset(buf, 'a', sizeof(buf));
    ASSERT_EQ(lseek(fd, 0, SEEK_SET), 0);
    ASSERT_EQ(write(fd, buf, sizeof(buf)), sizeof(buf));
    struct stat sb;
    ASSERT_EQ(fstat(fd, &sb), 0);
    ASSERT_EQ(sb.st_size, sizeof(buf));

    // Use F_GETFL; observe O_APPEND
    int flags = fcntl(fd, F_GETFL);
    ASSERT_GT(flags, -1, "Fcntl failed");
    ASSERT_EQ(flags & O_ACCMODE, O_RDWR, "Access mode flags did not match");
    ASSERT_EQ(flags & ~O_ACCMODE, O_APPEND, "Status flags did not match");

    // Use F_SETFL; try to turn off everything except O_APPEND
    // (if fcntl paid attention to access bits, this would make the file
    // read-only).
    ASSERT_EQ(fcntl(fd, F_SETFL, O_APPEND), 0, "Fcntl failed");

    // We're still appending -- AND writable, because the access bits haven't
    // changed.
    ASSERT_EQ(lseek(fd, 0, SEEK_SET), 0);
    ASSERT_EQ(write(fd, buf, sizeof(buf)), sizeof(buf));
    ASSERT_EQ(fstat(fd, &sb), 0);
    ASSERT_EQ(sb.st_size, sizeof(buf) * 2);

    // Clean up
    ASSERT_EQ(close(fd), 0);
    ASSERT_EQ(unlink("::file"), 0);
    END_TEST;
}

RUN_FOR_ALL_FILESYSTEMS(fcntl_tests,
    RUN_TEST_MEDIUM(TestFcntlAppend)
    RUN_TEST_MEDIUM(TestFcntlAccessBits)
)