source: MondoRescue/branches/3.3/mindi-busybox/coreutils/sync.c@ 3621

/* vi: set sw=4 ts=4: */
/*
 * Mini sync implementation for busybox
 *
 * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
 * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

/* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */
//config:config SYNC
//config:   bool "sync"
//config:   default y
//config:   help
//config:     sync is used to flush filesystem buffers.
//config:config FEATURE_SYNC_FANCY
//config:   bool "Enable -d and -f flags (requres syncfs(2) in libc)"
//config:   default y
//config:   depends on SYNC
//config:   help
//config:     sync -d FILE... executes fdatasync() on each FILE.
//config:     sync -f FILE... executes syncfs() on each FILE.

//kbuild:lib-$(CONFIG_SYNC) += sync.o
//applet:IF_SYNC(APPLET_NOFORK(sync, sync, BB_DIR_BIN, BB_SUID_DROP, sync))

//usage:#define sync_trivial_usage
//usage:       ""IF_FEATURE_SYNC_FANCY("[-df] [FILE]...")
//usage:#define sync_full_usage "\n\n"
//usage:    IF_NOT_FEATURE_SYNC_FANCY(
//usage:       "Write all buffered blocks to disk"
//usage:    )
//usage:    IF_FEATURE_SYNC_FANCY(
//usage:       "Write all buffered blocks (in FILEs) to disk"
//usage:     "\n    -d  Avoid syncing metadata"
//usage:     "\n    -f  Sync filesystems underlying FILEs"
//usage:    )

#include "libbb.h"

/* This is a NOFORK applet. Be very careful! */

int sync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int sync_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM))
{
#if !ENABLE_FEATURE_SYNC_FANCY
    /* coreutils-6.9 compat */
    bb_warn_ignoring_args(argv[1]);
    sync();
    return EXIT_SUCCESS;
#else
    unsigned opts;
    int ret = EXIT_SUCCESS;

    enum {
        OPT_DATASYNC = (1 << 0),
        OPT_SYNCFS   = (1 << 1),
    };

    opt_complementary = "d--f:f--d";
    opts = getopt32(argv, "df");
    argv += optind;

    /* Handle the no-argument case. */
    if (!argv[0])
        sync();

    while (*argv) {
        int fd = open_or_warn(*argv, O_RDONLY);

        if (fd < 0) {
            ret = EXIT_FAILURE;
            goto next;
        }
        if (opts & OPT_DATASYNC) {
            if (fdatasync(fd))
                goto err;
            goto do_close;
        }
        if (opts & OPT_SYNCFS) {
            /*
             * syncfs is documented to only fail with EBADF,
             * which can't happen here. So, no error checks.
             */
            syncfs(fd);
            goto do_close;
        }
        if (fsync(fd)) {
 err:
            bb_simple_perror_msg(*argv);
            ret = EXIT_FAILURE;
        }
 do_close:
        close(fd);
 next:
        ++argv;
    }

    return ret;
#endif
}