1/* SPDX-License-Identifier: BSD-2-Clause */
2/*
3 * dhcpcd - DHCP client daemon
4 * Copyright (c) 2006-2023 Roy Marples <roy@marples.name>
5 * All rights reserved
6
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/stat.h>
30#include <sys/statvfs.h>
31
32#include <ctype.h>
33#include <errno.h>
34#include <fcntl.h>
35#include <stdio.h>
36#include <stdlib.h>
37#include <string.h>
38
39#include "common.h"
40#include "dhcpcd.h"
41#include "if-options.h"
42
43const char *
44hwaddr_ntoa(const void *hwaddr, size_t hwlen, char *buf, size_t buflen)
45{
46	const unsigned char *hp, *ep;
47	char *p;
48
49	/* Allow a hwlen of 0 to be an empty string. */
50	if (buf == NULL || buflen == 0) {
51		errno = ENOBUFS;
52		return NULL;
53	}
54
55	if (hwlen * 3 > buflen) {
56		/* We should still terminate the string just in case. */
57		buf[0] = '\0';
58		errno = ENOBUFS;
59		return NULL;
60	}
61
62	hp = hwaddr;
63	ep = hp + hwlen;
64	p = buf;
65	while (hp < ep) {
66		if (hp != hwaddr)
67			*p ++= ':';
68		p += snprintf(p, 3, "%.2x", *hp++);
69	}
70	*p ++= '\0';
71	return buf;
72}
73
74size_t
75hwaddr_aton(uint8_t *buffer, const char *addr)
76{
77	char c[3];
78	const char *p = addr;
79	uint8_t *bp = buffer;
80	size_t len = 0;
81
82	c[2] = '\0';
83	while (*p != '\0') {
84		/* Skip separators */
85		c[0] = *p++;
86		switch (c[0]) {
87		case '\n':	/* long duid split on lines */
88		case ':':	/* typical mac address */
89		case '-':	/* uuid */
90			continue;
91		}
92		c[1] = *p++;
93		/* Ensure that digits are hex */
94		if (isxdigit((unsigned char)c[0]) == 0 ||
95		    isxdigit((unsigned char)c[1]) == 0)
96		{
97			errno = EINVAL;
98			return 0;
99		}
100		/* We should have at least two entries 00:01 */
101		if (len == 0 && *p == '\0') {
102			errno = EINVAL;
103			return 0;
104		}
105		if (bp)
106			*bp++ = (uint8_t)strtol(c, NULL, 16);
107		len++;
108	}
109	return len;
110}
111
112ssize_t
113readfile(const char *file, void *data, size_t len)
114{
115	int fd;
116	ssize_t bytes;
117
118	fd = open(file, O_RDONLY);
119	if (fd == -1)
120		return -1;
121	bytes = read(fd, data, len);
122	close(fd);
123	if ((size_t)bytes == len) {
124		errno = ENOBUFS;
125		return -1;
126	}
127	return bytes;
128}
129
130ssize_t
131writefile(const char *file, mode_t mode, const void *data, size_t len)
132{
133	int fd;
134	ssize_t bytes;
135
136	fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
137	if (fd == -1)
138		return -1;
139	bytes = write(fd, data, len);
140	close(fd);
141	return bytes;
142}
143
144int
145filemtime(const char *file, time_t *time)
146{
147	struct stat st;
148
149	if (stat(file, &st) == -1)
150		return -1;
151	*time = st.st_mtime;
152	return 0;
153}
154
155/* Handy routine to read very long lines in text files.
156 * This means we read the whole line and avoid any nasty buffer overflows.
157 * We strip leading space and avoid comment lines, making the code that calls
158 * us smaller. */
159char *
160get_line(char ** __restrict buf, ssize_t * __restrict buflen)
161{
162	char *p, *c;
163	bool quoted;
164
165	do {
166		p = *buf;
167		if (*buf == NULL)
168			return NULL;
169		c = memchr(*buf, '\n', (size_t)*buflen);
170		if (c == NULL) {
171			c = memchr(*buf, '\0', (size_t)*buflen);
172			if (c == NULL)
173				return NULL;
174			*buflen = c - *buf;
175			*buf = NULL;
176		} else {
177			*c++ = '\0';
178			*buflen -= c - *buf;
179			*buf = c;
180		}
181		for (; *p == ' ' || *p == '\t'; p++)
182			;
183	} while (*p == '\0' || *p == '\n' || *p == '#' || *p == ';');
184
185	/* Strip embedded comments unless in a quoted string or escaped */
186	quoted = false;
187	for (c = p; *c != '\0'; c++) {
188		if (*c == '\\') {
189			c++; /* escaped */
190			continue;
191		}
192		if (*c == '"')
193			quoted = !quoted;
194		else if (*c == '#' && !quoted) {
195			*c = '\0';
196			break;
197		}
198	}
199	return p;
200}
201
202
203int
204is_root_local(void)
205{
206#ifdef ST_LOCAL
207	struct statvfs vfs;
208
209	if (statvfs("/", &vfs) == -1)
210		return -1;
211	return vfs.f_flag & ST_LOCAL ? 1 : 0;
212#else
213	errno = ENOTSUP;
214	return -1;
215#endif
216}
217