dfs.cmds/general/general.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */


/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 *  generic interface to dfs commands.
 *
 *  usage:  cmd [-F fstype] [-o fs_options] [ args ]
 *
 *  exec's /usr/lib/fs/<fstype>/<cmd>
 *  <cmd> is the basename of the command.
 *
 *  if -F is missing, fstype is the first entry in /etc/dfs/fstypes
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <string.h>

#define DFSTYPES    "/etc/dfs/fstypes"      /* dfs list */
#define FSCMD       "/usr/lib/fs/%s/%s"

#define ARGVPAD     4   /* non-[arg...] elements in new argv list: */
                /* cmd name, -o, opts, (char *)0 terminator */

static char *getfs();
static int invalid();
void perror();

int
main(argc, argv)
int argc;
char **argv;
{
    extern char *optarg;
    extern int optind;
    FILE *dfp;      /* fp for dfs list */
    int c, err = 0;
    char subcmd[BUFSIZ];    /* fs specific command */
    char *cmd;      /* basename of this command */
    char *fsname = NULL;    /* file system name */
    char *opts = NULL;  /* -o options */
    char **nargv;       /* new argv list */
    int nargc = 0;      /* new argc */
    static char usage[] =
        "usage: %s [-F fstype] [-o fs_options ] [arg ...]\n";

    cmd = strrchr(argv[0], '/');    /* find the basename */
    if (cmd)
        ++cmd;
    else
        cmd = argv[0];

    while ((c = getopt(argc, argv, "F:o:")) != -1)
        switch (c) {
        case 'F':
            err |= (fsname != NULL);    /* at most one -F */
            fsname = optarg;
            break;
        case 'o':           /* fs specific options */
            err |= (opts != NULL);      /* at most one -o */
            opts = optarg;
            break;
        case '?':
            err = 1;
            break;
        }
    if (err) {
        (void) fprintf(stderr, usage, cmd);
        exit(1);
    }

    if ((dfp = fopen(DFSTYPES, "r")) == NULL) {
        (void) fprintf(stderr, "%s: cannot open %s\n",
            cmd, DFSTYPES);
        exit(1);
    }

    if (fsname) {       /* generate fs specific command name */
        if (invalid(fsname, dfp)) { /* valid ? */
            (void) fprintf(stderr,
                "%s: invalid file system name\n", cmd);
            (void) fprintf(stderr, usage, cmd);
            exit(1);
        } else {
            (void) snprintf(subcmd, sizeof (subcmd),
                FSCMD, fsname, cmd);
        }
    } else if (fsname = getfs(dfp)) {   /* use 1st line in dfstypes */
        (void) snprintf(subcmd, sizeof (subcmd), FSCMD, fsname, cmd);
    } else {
        (void) fprintf(stderr,
            "%s: no file systems in %s\n", cmd, DFSTYPES);
        (void) fprintf(stderr, usage, cmd);
        exit(1);
    }

    /* allocate a block for the new argv list */
    if (!(nargv = (char **)malloc(sizeof (char *)*(argc-optind+ARGVPAD)))) {
        (void) fprintf(stderr, "%s: malloc failed.\n", cmd);
        exit(1);
        /*NOTREACHED*/
    }
    nargv[nargc++] = cmd;
    if (opts) {
        nargv[nargc++] = "-o";
        nargv[nargc++] = opts;
    }
    for (; optind <= argc; ++optind)    /* this copies the last NULL */
        nargv[nargc++] = argv[optind];

    (void) execvp(subcmd, nargv);
    perror(subcmd);
    return (1);
}


/*
 *  invalid(name, f)  -  return non-zero if name is not in
 *               the list of fs names in file f
 */

static int
invalid(name, f)
char *name;     /* file system name */
FILE *f;        /* file of list of systems */
{
    char *s;

    while (s = getfs(f))    /* while there's still hope ... */
        if (strcmp(s, name) == 0)
            return (0); /* we got it! */
    return (1);
}


/*
 *  getfs(fp) - get the next file system name from fp
 *      ignoring lines starting with a #.
 *      All leading whitespace is discarded.
 */

static char buf[BUFSIZ];

static char *
getfs(fp)
FILE *fp;
{
    char *s;

    while (s = fgets(buf, BUFSIZ, fp)) {
        while (isspace(*s)) /* leading whitespace doesn't count */
            ++s;
        if (*s != '#') {    /* not a comment */
            char *t = s;

            while (!isspace(*t))    /* get the token */
                ++t;
            *t = '\0';      /* ignore rest of line */
            return (s);
        }
    }
    return (NULL);  /* that's all, folks! */
}