tests/file-locking/runtests.c

	runtests.c revision 90221f9148b67fdc90178b67f9600b7bd4e3bc7c
/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2016 Joyent, Inc.
 */

/*
 * Validate various fcntl(2) and flock(3C) operations.
 */

#include "util.h"
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <signal.h>
#include <stdlib.h>
#include <strings.h>
#include <sys/debug.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <unistd.h>


#define LOCKFILE_FMT    "/tmp/.lockfile-%s-%ld"
#define LOCKDIR_FMT "/tmp/.lockdir-%s-%ld"

typedef struct lockinfo {
    char *lf_name;
    char *lf_path;
    int lf_fd;
} lockinfo_t;


static  void    assert_write_locked_by(lockinfo_t *, pid_t);
static  void    assert_read_locked_by(lockinfo_t *, pid_t);
static  void    assert_unlocked(lockinfo_t *);
static  void    assert_all_unlocked(void);

static  int flock_copyfil(lockinfo_t *, lockinfo_t *);
static  int flock_mkfil(lockinfo_t *);
static  int flock_mkdir(lockinfo_t *);
static  void    flock_rminfo(lockinfo_t *);

static  void    flock_fcntl(lockinfo_t *lf, int cmd, struct flock *fl);
static  void    flock_run(lock_style_t, boolean_t, lockinfo_t *,
            pid_t *, int[]);
static  int flock_wait(pid_t pid);
static  void    flock_cleanup_child(pid_t, int []);

static  void    flock_test_invalid(lockinfo_t *, int, short, short,
            off_t, off_t);
static  void    flock_test_exclusive(lock_style_t, lock_style_t,
            lockinfo_t *, lockinfo_t *, boolean_t);
static  void    flock_test_shared(lock_style_t, lock_style_t, lockinfo_t *,
            lockinfo_t *, boolean_t);
static  void    flock_test_upgrade_downgrade(void);

static char *acqprog = NULL;

static lockinfo_t flock_fileA = { "a", NULL, -1 };
static lockinfo_t flock_fileB = { "b", NULL, -1 };
static lockinfo_t flock_dirA = { "a", NULL, -1 };
static lockinfo_t flock_dirB = { "b", NULL, -1 };


static short cmds[8] = {
    F_SETLK, F_SETLKW, F_GETLK,
    F_OFD_SETLK, F_OFD_SETLKW, F_OFD_GETLK,
    F_FLOCK, F_FLOCKW
};


static void
flock_kill(pid_t pid)
{
    while (kill(pid, SIGKILL) == -1) {
        if (errno == EINTR)
            continue;

        err(EXIT_FAILURE, "kill failed");
    }
}


static void
flock_fcntl(lockinfo_t *lf, int cmd, struct flock *fl)
{
    if (fcntl(lf->lf_fd, cmd, fl) == -1) {
        err(EXIT_FAILURE, "fcntl failed");
    }
}


static void
assert_write_locked_by(lockinfo_t *lf, pid_t pid)
{
    struct flock fl;

    flock_reinit(&fl, F_WRLCK);
    flock_fcntl(lf, F_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_WRLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, pid, pid_t);

    flock_reinit(&fl, F_WRLCK);
    flock_fcntl(lf, F_OFD_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_WRLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, pid, pid_t);

    flock_reinit(&fl, F_RDLCK);
    flock_fcntl(lf, F_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_WRLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, pid, pid_t);

    flock_reinit(&fl, F_RDLCK);
    flock_fcntl(lf, F_OFD_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_WRLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, pid, pid_t);
}


static void
assert_read_locked_by(lockinfo_t *lf, pid_t pid)
{
    struct flock fl;

    flock_reinit(&fl, F_WRLCK);
    flock_fcntl(lf, F_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_RDLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, pid, pid_t);

    flock_reinit(&fl, F_WRLCK);
    flock_fcntl(lf, F_OFD_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_RDLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, pid, pid_t);

    flock_reinit(&fl, F_RDLCK);
    flock_fcntl(lf, F_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_UNLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, 0, pid_t);

    flock_reinit(&fl, F_RDLCK);
    flock_fcntl(lf, F_OFD_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_UNLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, 0, pid_t);
}

static void
assert_unlocked(lockinfo_t *lf)
{
    struct flock fl;

    flock_reinit(&fl, F_WRLCK);
    flock_fcntl(lf, F_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_UNLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, 0, pid_t);

    flock_reinit(&fl, F_WRLCK);
    flock_fcntl(lf, F_OFD_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_UNLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, 0, pid_t);

    flock_reinit(&fl, F_RDLCK);
    flock_fcntl(lf, F_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_UNLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, 0, pid_t);

    flock_reinit(&fl, F_RDLCK);
    flock_fcntl(lf, F_OFD_GETLK, &fl);
    VERIFY3_IMPL(fl.l_type, ==, F_UNLCK, short);
    VERIFY3_IMPL(fl.l_sysid, ==, 0, int);
    VERIFY3_IMPL(fl.l_pid, ==, 0, pid_t);
}


static void
assert_all_unlocked(void)
{
    assert_unlocked(&flock_fileA);
    assert_unlocked(&flock_fileB);
    assert_unlocked(&flock_dirA);
    assert_unlocked(&flock_dirB);
}


static int
flock_copyfil(lockinfo_t *src, lockinfo_t *dst)
{
    dst->lf_name = NULL;
    dst->lf_path = NULL;
    if ((dst->lf_fd = open(src->lf_path, O_RDWR)) == -1) {
        warn("Failed to open %s", src->lf_path);
        return (-1);
    }

    return (0);
}


static int
flock_mkfil(lockinfo_t *lf)
{
    if (asprintf(&lf->lf_path, LOCKFILE_FMT, lf->lf_name, getpid()) < 0) {
        warnx("Failed to generate lockfile name");
        return (-1);
    }

    if ((lf->lf_fd = open(lf->lf_path, O_RDWR|O_CREAT, 0600)) == -1)  {
        warn("Failed to open %s", lf->lf_path);
        return (-1);
    }

    return (0);
}


static int
flock_mkdir(lockinfo_t *lf)
{
    if (asprintf(&lf->lf_path, LOCKDIR_FMT, lf->lf_name, getpid()) < 0) {
        warnx("Failed to generate lockfile name");
        return (-1);
    }

    if (mkdir(lf->lf_path, 0700) == -1)  {
        warn("Failed to make %s", lf->lf_path);
        return (-1);
    }

    if ((lf->lf_fd = open(lf->lf_path, O_RDONLY)) == -1)  {
        warn("Failed to open %s", lf->lf_path);
        return (-1);
    }

    return (0);
}


static void
flock_rminfo(lockinfo_t *lf)
{
    if (lf->lf_fd != -1) {
        (void) close(lf->lf_fd);
    }
    if (lf->lf_path != NULL) {
        (void) unlink(lf->lf_path);
        free(lf->lf_path);
    }
}


static void
flock_run(lock_style_t style, boolean_t is_exclusive, lockinfo_t *lf,
    pid_t *pid, int fds[])
{
    char *stylestr = flock_stylestr(style);
    char *modestr = is_exclusive ? "exclusive" : "shared";
    char *argv[5] = { acqprog, stylestr, modestr, lf->lf_path, NULL };
    int ret = pipe(fds);
    if (ret == -1) {
        err(EXIT_FAILURE, "pipe failed");
    }

    *pid = fork();
    if (*pid == (pid_t)-1) {
        err(EXIT_FAILURE, "fork failed");
    } else if (*pid == (pid_t)0) {
        /* Set up pipe for communicating with child */
        ret = dup2(fds[1], 0);
        if (ret == -1) {
            err(EXIT_FAILURE, "dup2 failed");
        }
        ret = dup2(fds[1], 1);
        if (ret == -1) {
            err(EXIT_FAILURE, "dup2 failed");
        }
        closefrom(3);

        (void) execv(acqprog, argv);
        err(EXIT_FAILURE, "Failed to execute %s", acqprog);
    }
}


static int
flock_wait(pid_t pid)
{
    int childstat = 0;

    while (waitpid(pid, &childstat, 0) == -1) {
        if (errno == EINTR)
            continue;

        err(EXIT_FAILURE, "Failed to wait on child");
    }

    if (WIFEXITED(childstat)) {
        return (WEXITSTATUS(childstat));
    } else if (WIFSIGNALED(childstat)) {
        return (1);
    } else {
        abort();
        return (1);
    }
}


static void
flock_cleanup_child(pid_t pid, int fds[])
{
    (void) flock_wait(pid);
    (void) close(fds[0]);
    (void) close(fds[1]);
}


static void
flock_test_upgrade_downgrade(void)
{
    lockinfo_t afd1, afd2, afd3;
    pid_t pid;
    int fds[2];

    VERIFY3S(flock_copyfil(&flock_fileA, &afd1), ==, 0);
    VERIFY3S(flock_copyfil(&flock_fileA, &afd2), ==, 0);
    VERIFY3S(flock_copyfil(&flock_fileA, &afd3), ==, 0);

    flock_log("Acquiring shared locks 1, 2 and 3...");
    VERIFY3S(flock(afd1.lf_fd, LOCK_SH), ==, 0);
    VERIFY3S(flock(afd2.lf_fd, LOCK_SH), ==, 0);
    VERIFY3S(flock(afd3.lf_fd, LOCK_SH), ==, 0);
    assert_read_locked_by(&flock_fileA, -1);
    flock_log(" ok\n");

    flock_log("Upgrading lock 3 should fail w/ EWOULDBLOCK...");
    VERIFY3S(flock(afd3.lf_fd, LOCK_EX|LOCK_NB), ==, -1);
    VERIFY3U(errno, ==, EWOULDBLOCK);
    assert_read_locked_by(&flock_fileA, -1);
    flock_log(" ok\n");

    flock_log("Upgrading 3 should succeed after releasing locks 1 & 2...");
    VERIFY3S(flock(afd1.lf_fd, LOCK_UN), ==, 0);
    VERIFY3S(flock(afd2.lf_fd, LOCK_UN), ==, 0);
    VERIFY3S(flock(afd3.lf_fd, LOCK_EX), ==, 0);
    assert_write_locked_by(&flock_fileA, -1);
    flock_log(" ok\n");


    flock_log("Starting up child, then downgrading lock 3 to shared...");
    flock_run(LSTYLE_FLOCK, B_FALSE, &flock_fileA, &pid, fds);
    VERIFY3_IMPL(flock_nodata(fds[0]), ==, B_TRUE, boolean_t);
    VERIFY3S(flock(afd3.lf_fd, LOCK_SH), ==, 0);
    flock_block(fds[0]);
    assert_read_locked_by(&flock_fileA, -1);
    flock_log(" ok\n");

    flock_log("Releasing child and upgrading...");
    flock_alert(fds[0]);
    flock_cleanup_child(pid, fds);
    assert_read_locked_by(&flock_fileA, -1);
    VERIFY3S(flock(afd3.lf_fd, LOCK_EX), ==, 0);
    assert_write_locked_by(&flock_fileA, -1);
    flock_log(" ok\n");

    flock_log("Releasing lock 3...");
    VERIFY3S(flock(afd3.lf_fd, LOCK_UN), ==, 0);
    flock_rminfo(&afd1);
    flock_rminfo(&afd2);
    flock_rminfo(&afd3);
    assert_all_unlocked();
    flock_log(" ok\n");
}


static void
flock_test_invalid(lockinfo_t *lf, int cmd, short l_type, short l_whence,
    off_t l_start, off_t l_len)
{
    struct flock fl = {
        .l_type = l_type,
        .l_whence = l_whence,
        .l_start = l_start,
        .l_len = l_len
    };

    flock_log("fcntl(fd, %s, { %hd, %hd, %ld, %ld, ... })...",
        flock_cmdname(cmd), l_type, l_whence, l_start, l_len);
    VERIFY3S(fcntl(lf->lf_fd, cmd, &fl), ==, -1);
    VERIFY3U(errno, ==, EINVAL);
    flock_log(" ok\n");
}


static void
flock_test_exclusive(lock_style_t styleA, lock_style_t styleB,
    lockinfo_t *lock1, lockinfo_t *lock2, boolean_t kill_firstborn)
{
    pid_t pidA, pidB;
    int fdsA[2], fdsB[2];

    flock_log("Running %s + %s tests (%s)...",
        flock_stylename(styleA), flock_stylename(styleB),
        kill_firstborn ? "kill child" : "child exits");

    /* Create child, and wait for it to acquire the lock */
    flock_run(styleA, B_TRUE, lock1, &pidA, fdsA);
    flock_block(fdsA[0]);

    /* Create second child, which shouldn't acquire & signal */
    flock_run(styleB, B_TRUE, lock1, &pidB, fdsB);
    VERIFY3_IMPL(flock_nodata(fdsB[0]), ==, B_TRUE, boolean_t);

    /* lock1 is blocked for reading and writing */
    assert_write_locked_by(lock1, styleA == LSTYLE_POSIX ? pidA : -1);
    assert_unlocked(lock2);

    /* Tell pidA to exit */
    if (kill_firstborn) {
        flock_kill(pidA);
    } else {
        flock_alert(fdsA[0]);
    }
    flock_cleanup_child(pidA, fdsA);

    /* Wait for pidB to signal us */
    flock_block(fdsB[0]);

    /* lock1 is blocked for reading and writing */
    assert_write_locked_by(lock1, styleB == LSTYLE_POSIX ? pidB : -1);
    assert_unlocked(lock2);

    /* Tell pidB to exit */
    flock_alert(fdsB[0]);

    flock_cleanup_child(pidB, fdsB);

    /*
     * Tests after child has released lock
     */
    assert_all_unlocked();

    flock_log(" ok\n");
}


static void
flock_test_shared(lock_style_t styleA, lock_style_t styleB,
    lockinfo_t *lock1, lockinfo_t *lock2, boolean_t kill_firstborn)
{
    pid_t pidA, pidB;
    int fdsA[2], fdsB[2];

    flock_log("Running %s + %s tests (%s)...",
        flock_stylename(styleA), flock_stylename(styleB),
        kill_firstborn ? "kill child" : "child exits");

    /* Create children, and wait for it to acquire the lock */
    flock_run(styleB, B_FALSE, lock1, &pidB, fdsB);
    flock_block(fdsB[0]);
    flock_run(styleA, B_FALSE, lock1, &pidA, fdsA);
    flock_block(fdsA[0]);

    /* testfileA is only blocked for writing */
    assert_read_locked_by(lock1, styleA == LSTYLE_POSIX ? pidA : -1);
    assert_unlocked(lock2);

    /* Tell pidA to exit */
    if (kill_firstborn) {
        flock_kill(pidA);
    } else {
        flock_alert(fdsA[0]);
    }
    flock_cleanup_child(pidA, fdsA);

    /* testfileA is still blocked for writing by pidB */
    assert_read_locked_by(lock1, styleB == LSTYLE_POSIX ? pidB : -1);
    assert_unlocked(lock2);

    /* Tell pidB to exit */
    flock_alert(fdsB[0]);
    flock_cleanup_child(pidB, fdsB);

    assert_all_unlocked();

    flock_log(" ok\n");
}


static void
flock_test_ofd_sameproc(void)
{
    lockinfo_t afd1, afd2, afd3;

    VERIFY3S(flock_copyfil(&flock_fileA, &afd1), ==, 0);
    VERIFY3S(flock_copyfil(&flock_fileA, &afd2), ==, 0);
    VERIFY3S(flock_copyfil(&flock_fileA, &afd3), ==, 0);

    flock_log("Acquiring first two shared locks...");
    VERIFY3S(flock(afd1.lf_fd, LOCK_SH), ==, 0);
    VERIFY3S(flock(afd2.lf_fd, LOCK_SH), ==, 0);
    assert_read_locked_by(&flock_fileA, -1);
    flock_log(" ok\n");

    flock_log("Acquiring an exclusive lock should fail w/ EWOULDBLOCK...");
    VERIFY3S(flock(afd3.lf_fd, LOCK_EX|LOCK_NB), ==, -1);
    VERIFY3U(errno, ==, EWOULDBLOCK);
    flock_log(" ok\n");

    flock_log("Releasing to acquire an exclusive lock...");
    VERIFY3S(flock(afd1.lf_fd, LOCK_UN), ==, 0);
    VERIFY3S(flock(afd2.lf_fd, LOCK_UN), ==, 0);
    flock_log(" ok\n");

    flock_log("Acquiring an exclusive lock...");
    VERIFY3S(flock(afd3.lf_fd, LOCK_EX), ==, 0);
    assert_write_locked_by(&flock_fileA, -1);
    flock_log(" ok\n");

    flock_log("Acquiring a shared lock should fail w/ EWOULDBLOCK...");
    VERIFY3S(flock(afd1.lf_fd, LOCK_EX|LOCK_NB), ==, -1);
    VERIFY3U(errno, ==, EWOULDBLOCK);
    VERIFY3S(flock(afd2.lf_fd, LOCK_EX|LOCK_NB), ==, -1);
    VERIFY3U(errno, ==, EWOULDBLOCK);
    flock_log(" ok\n");

    flock_log("Releasing exclusive lock...");
    VERIFY3S(flock(afd3.lf_fd, LOCK_UN), ==, 0);
    assert_all_unlocked();
    flock_log(" ok\n");

    flock_rminfo(&afd1);
    flock_rminfo(&afd2);
    flock_rminfo(&afd3);
}


static void
flock_runtests(void)
{
    lock_style_t first, second;
    int i;

    flock_log("# Exclusive lock tests\n");
    for (first = (lock_style_t)0; first < LSTYLE_LAST; first++) {
        for (second = (lock_style_t)0; second < LSTYLE_LAST; second++) {
            flock_test_exclusive(first, second,
                &flock_fileA, &flock_fileB, B_TRUE);
            flock_test_exclusive(first, second,
                &flock_fileA, &flock_fileB, B_FALSE);
        }
    }

    flock_log("# Shared lock tests\n");
    for (first = (lock_style_t)0; first < LSTYLE_LAST; first++) {
        for (second = (lock_style_t)0; second < LSTYLE_LAST; second++) {
            flock_test_shared(first, second,
                &flock_fileA, &flock_fileB, B_TRUE);
            flock_test_shared(first, second,
                &flock_fileA, &flock_fileB, B_FALSE);
        }
    }

    flock_log("# flock(3C) directory lock tests\n");
    flock_test_exclusive(LSTYLE_FLOCK, LSTYLE_FLOCK,
        &flock_dirA, &flock_dirB, B_TRUE);
    flock_test_exclusive(LSTYLE_FLOCK, LSTYLE_FLOCK,
        &flock_dirA, &flock_dirB, B_FALSE);
    flock_test_shared(LSTYLE_FLOCK, LSTYLE_FLOCK,
        &flock_dirA, &flock_dirB, B_TRUE);
    flock_test_shared(LSTYLE_FLOCK, LSTYLE_FLOCK,
        &flock_dirA, &flock_dirB, B_FALSE);


    flock_log("# Invalid fcntl(2) parameters tests\n");
    for (i = 0; i < sizeof (cmds) / sizeof (short); i++) {
        flock_test_invalid(&flock_fileA, cmds[i], 200, 0, 0, 0);
        flock_test_invalid(&flock_fileA, cmds[i], -1, 0, 0, 0);
    }
    for (i = 3; i < sizeof (cmds) / sizeof (short); i++) {
        flock_test_invalid(&flock_fileA, cmds[i], F_WRLCK, 1, 0, 0);
        flock_test_invalid(&flock_fileA, cmds[i], F_WRLCK, 0, 1, 0);
        flock_test_invalid(&flock_fileA, cmds[i], F_WRLCK, 0, 0, 1);
    }

    flock_log("# Testing that multiple OFD locks work in a process\n");
    flock_test_ofd_sameproc();

    flock_log("# Testing flock(3C) upgrade/downgrade tests\n");
    flock_test_upgrade_downgrade();
}


int
main(int argc, char *argv[])
{
    char *basestr, *suffix, *dirstr, *dirpath;
    pid_t testrunner;
    int exval;

    LOG = B_TRUE;

    if (argc < 1) {
        errx(EXIT_FAILURE, "Can't find program name!");
    }

    dirstr = strdup(argv[0]);
    dirpath = dirname(dirstr);
    basestr = strdup(argv[0]);
    suffix = basename(basestr);

    while (*suffix != '.' && *suffix != '\0') {
        suffix += 1;
    }

    if (asprintf(&acqprog, "%s/acquire-lock%s", dirpath, suffix) < 0) {
        errx(EXIT_FAILURE,
            "Can't generate lock acquisition program name!");
    }

    if (access(acqprog, X_OK) != 0) {
        err(EXIT_FAILURE,
            "Can't run lock acquisition program %s", acqprog);
    }

    /* Create several lockfiles for testing */
    if (flock_mkfil(&flock_fileA) != 0 ||
        flock_mkfil(&flock_fileB) != 0 ||
        flock_mkdir(&flock_dirA) != 0 ||
        flock_mkdir(&flock_dirB) != 0) {
        exval = 1;
        goto cleanup;
    }

    /*
     * We run the tests in a child process so that when tests fail
     * we can still clean up our temporary files.
     */
    testrunner = fork();
    if (testrunner == (pid_t)-1) {
        err(EXIT_FAILURE, "Unable to fork to run tests");
    } else if (testrunner == (pid_t)0) {
        flock_runtests();
        return (0);
    }

    exval = flock_wait(testrunner);

cleanup:
    free(basestr);
    free(dirstr);
    flock_rminfo(&flock_fileA);
    flock_rminfo(&flock_fileB);
    flock_rminfo(&flock_dirA);
    flock_rminfo(&flock_dirB);
    return (exval);
}