/*
 * 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) 1984, 1986, 1987, 1988, 1989 AT&T	*/
/*	  All Rights Reserved	*/


/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 *	generic interface to dfshares, dfmounts.
 *
 *	usage:	dfshares [-F fstype] [-o fs_options] [-h] [ 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 <dirent.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <wait.h>
#include <stdlib.h>

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

/*
 * non-[arg...] elements in new argv list:
 * cmd name, , -h, -o, opts, (char *)0 terminator
 */
#define	ARGVPAD		5

static char *getfs(FILE *);
static int invalid(const char *, FILE *);

int
main(int argc, char **argv)
{
	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 hflag = 0;
	int nargc = 0;		/* new argc */
	pid_t pid;		/* pid for fork */
	int retval;		/* exit status from exec'd commad */
	int showall = (argc <= 1);	/* show all resources */
	static char usage[] =
	    "usage: %s [-F fstype] [-h] [-o fs_options ] [arg ...]\n";

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

	while ((c = getopt(argc, argv, "hF:o:")) != -1)
		switch (c) {
		case 'h':
			hflag = 1;	/* no header ... pass to subcommand */
			break;
		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);
	}

	/* 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);
	}
	nargv[nargc++] = cmd;
	if (hflag)
		nargv[nargc++] = "-h";
	if (opts) {
		nargv[nargc++] = "-o";
		nargv[nargc++] = opts;
	}
	for (; optind <= argc; ++optind)	/* this copies the last NULL */
		nargv[nargc++] = argv[optind];

	if (showall) {		/* command with no args -- show all dfs's */
		pid = 0;
		while ((fsname = getfs(dfp)) != NULL) {
			(void) snprintf(subcmd, sizeof (subcmd),
			    FSCMD, fsname, cmd);
			switch (pid = fork()) {		/* do the subcommand */
			case 0:
				(void) execvp(subcmd, nargv);
				if (errno != ENOENT)
					perror(subcmd);
				_exit(1);
				/*NOTREACHED*/
			default:
				while (wait(&retval) != pid)
					;
				/* take exit status into account */
				err |= (retval & 0xff00) >> 8;
				break;
			case -1:
				(void) fprintf(stderr,
				    "%s: fork failed - try again later.\n",
				    cmd);
				exit(1);
			}
		}
		(void) fclose(dfp);
		if (pid == 0) {		/* we never got into the loop! */
			(void) fprintf(stderr,
			    "%s: no file systems in %s\n",
			    cmd, DFSTYPES);
			(void) fprintf(stderr, usage, cmd);
			exit(1);
		} else {
			exit(err);
		}
	}

	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)) != NULL) /* 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);
	}

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


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

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

	while ((s = getfs(f)) != NULL)	/* 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(FILE *fp)
{
	char *s;

	while ((s = fgets(buf, BUFSIZ, fp)) != NULL) {
		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! */
}