1/*
2 * Copyright (c) 2005 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * The contents of this file constitute Original Code as defined in and
7 * are subject to the Apple Public Source License Version 1.1 (the
8 * "License").  You may not use this file except in compliance with the
9 * License.  Please obtain a copy of the License at
10 * http://www.apple.com/publicsource and read it before using this file.
11 *
12 * This Original Code and all software distributed under the License are
13 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
17 * License for the specific language governing rights and limitations
18 * under the License.
19 *
20 * @APPLE_LICENSE_HEADER_END@
21 */
22
23#include <sys/errno.h>
24#include <sys/types.h>
25#include <sys/stat.h>
26#include <sys/wait.h>
27
28#include <err.h>
29#include <fcntl.h>
30#include <fstab.h>
31#include <stdio.h>
32#include <stdlib.h>
33#include <string.h>
34#include <paths.h>
35#include <unistd.h>
36#include <signal.h>
37
38char *warning = "\
39#\n\
40# Warning - this file should only be modified with vifs(8)\n\
41#\n\
42# Failure to do so is unsupported and may be destructive.\n\
43#\n";
44
45int
46main(int argc, char *argv[])
47{
48	struct stat sb;
49	int fd, x;
50	uid_t euid;
51	pid_t editpid;
52	char *p, *editor;
53
54	if (argc != 1) {
55		printf("usage: vifs\n");
56		exit(1);
57	}
58
59	euid = geteuid();
60	if (euid != 0)
61		errx(1, "need to run as root");
62
63	/* examine the existing fstab, try to create it if needed */
64	if (stat(_PATH_FSTAB, &sb) < 0) {
65		if (errno == ENOENT) {
66			fd = open(_PATH_FSTAB, O_CREAT | O_WRONLY,
67			     S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
68			if (fd < 0)
69				errx(1, "error creating %s", _PATH_FSTAB);
70			write(fd, warning, strlen(warning));
71			close(fd);
72		} else {
73			errx(1, "could not stat %s", _PATH_FSTAB);
74		}
75	}
76
77	/* prepare the file for the editor */
78	fd = open(_PATH_FSTAB, O_RDONLY, 0);
79	if (fd < 0)
80		errx(1, "error opening %s", _PATH_FSTAB);
81
82	x = fcntl(fd, F_SETFD, 1);
83	if (x < 0)
84		errx(1, "error setting close on exit");
85
86	x = flock(fd, LOCK_EX | LOCK_NB);
87	if (x != 0)
88		errx(1, "file is busy");
89
90	/* obtain and invoke the editor */
91	editor = getenv("EDITOR");
92	if (editor == NULL)
93		editor = _PATH_VI;
94	p = strrchr(editor, '/');
95        if (p != NULL)
96		++p;
97	else
98		p = editor;
99
100	editpid = vfork();
101	if (editpid == 0) {
102		execlp(editor, p, _PATH_FSTAB, NULL);
103		_exit(1);
104	}
105
106	for ( ; ; ) {
107		editpid = waitpid(editpid, (int *)&x, WUNTRACED);
108		if (editpid == -1)
109			errx(1, "editing error");
110		else if (WIFSTOPPED(x))
111			raise(WSTOPSIG(x));
112		else if (WIFEXITED(x) && WEXITSTATUS(x) == 0)
113			break;
114                else
115			errx(1, "editing error");
116	}
117
118	/* let process death clean up locks and file descriptors */
119	return 0;
120}
121