cmd/runat/runat.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2001 by Sun Microsystems, Inc.
 * All rights reserved.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * runat: run a command in attribute directory.
 *
 * runat file [command]
 *
 * when command is not specified an interactive shell is started
 * in the attribute directory.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <libintl.h>
#include <errno.h>
#include <strings.h>

static void
usage()
{
    (void) fprintf(stderr, gettext("usage: runat filename [command]\n"));
}

int
main(int argc, char *argv[])
{
    int fd;
    int dirfd;
    int i;
    int argslen;
    char *shell;
    char *args[4];
    char *cmdargs;

    if (argc < 2) {
        usage();
        exit(127);
    }

    if ((fd = open64(argv[1], O_RDONLY)) == -1) {
        (void) fprintf(stderr,
            gettext("runat: cannot open %s: %s\n"), argv[1],
            strerror(errno));
        exit(125);
    }

    if ((dirfd = openat64(fd, ".", O_RDONLY|O_XATTR)) == -1) {
        (void) fprintf(stderr,
            gettext("runat: cannot open attribute"
            " directory for %s: %s\n"), argv[1], strerror(errno));
        exit(125);
    }

    (void) close(fd);

    if (fchdir(dirfd) == -1) {
        (void) fprintf(stderr,
            gettext("runat: cannot fchdir to attribute"
            " directory: %s\n"), strerror(errno));
        exit(125);
    }

    if (argc < 3) {
        shell = getenv("SHELL");
        if (shell == NULL) {
            (void) fprintf(stderr,
                gettext(
                "runat: shell not found, using /bin/sh\n"));
            shell = "/bin/sh";
        }

        (void) execl(shell, shell, NULL);
        (void) fprintf(stderr,
            gettext("runat: Failed to exec %s: %s\n"), shell,
            strerror(errno));
        return (126);
    }

    /*
     * Count up the size of all of the args
     */

    for (i = 2, argslen = 0; i < argc; i++) {
        argslen += strlen(argv[i]) + 1;
    }

    cmdargs = calloc(1, argslen);
    if (cmdargs == NULL) {
        (void) fprintf(stderr, gettext(
            "runat: failed to allocate memory for"
            " command arguments: %s\n"), strerror(errno));
        exit(126);
    }


    /*
     * create string with all of the args concatenated together
     * This is done so that the shell will interpret the args
     * and do globbing if necessary.
     */
    for (i = 2; i < argc; i++) {
        if (strlcat(cmdargs, argv[i], argslen) >= argslen) {
            (void) fprintf(stderr, gettext(
                "runat: arguments won't fit in"
                " allocated buffer\n"));
            exit(126);
        }

        /*
         * tack on a space if there are more args
         */
        if ((i + 1) < argc) {
            if (strlcat(cmdargs, " ", argslen) >= argslen) {
                (void) fprintf(stderr, gettext(
                    "runat: arguments won't fit in"
                    " allocated buffer\n"));
                exit(126);
            }
        }

    }

    args[0] = "/bin/sh";
    args[1] = "-c";
    args[2] = cmdargs;
    args[3] = NULL;
    (void) execvp(args[0], args);
    (void) fprintf(stderr, gettext("runat: Failed to exec %s: %s\n"),
        argv[0], strerror(errno));
    return (126);
}