File: write_interface.c

package info (click to toggle)
netcfg 1.160
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 3,532 kB
  • sloc: ansic: 5,361; sh: 183; makefile: 77
file content (277 lines) | stat: -rw-r--r-- 8,975 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
/*
 * Functions to write things into /etc/network/interfaces
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include "netcfg.h"
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <debian-installer.h>

static int nc_wi_header(FILE *fd)
{
	fprintf(fd, "# This file describes the network interfaces available on your system\n");
	fprintf(fd, "# and how to activate them. For more information, see interfaces(5).\n");
	fprintf(fd, "\nsource /etc/network/interfaces.d/*\n");
	
	return 1;
}

static int nc_wi_loopback(const struct netcfg_interface *interface, FILE *fd)
{
	fprintf(fd, "\n# The loopback network interface\n");
	fprintf(fd, "auto %s\n", interface->name);
	fprintf(fd, "iface %s inet loopback\n", interface->name);
	
	return 1;
}

static int nc_wi_wireless_options(const struct netcfg_interface *interface, FILE *fd)
{
	/*
	 * Write wireless-tools options
	 */
	/* FIXME: Whether this is a wireless interface should be stored
	 * with the interface
	 */
	if (interface->wpa_supplicant_status == WPA_QUEUED) {
		fprintf(fd, "\twpa-ssid %s\n", interface->essid);
		fprintf(fd, "\twpa-psk  %s\n", interface->passphrase);
	} else {
		fprintf(fd, "\t# wireless-* options are implemented by the wireless-tools package\n");
		fprintf(fd, "\twireless-mode %s\n",
			(interface->mode == MANAGED) ? "managed" : "ad-hoc");
		fprintf(fd, "\twireless-essid %s\n",
		    (interface->essid && *interface->essid) ? interface->essid : "any");

		if (interface->wepkey != NULL)
			fprintf(fd, "\twireless-key1 %s\n", interface->wepkey);
	}

	return 1;
}

/* Write out a DHCP stanza for the given interface
 */
static int nc_wi_dhcp(const struct netcfg_interface *interface, FILE *fd)
{
	fprintf(fd, "\n# The primary network interface\n");
	if (!iface_is_hotpluggable(interface->name) && !find_in_stab(interface->name))
		fprintf(fd, "auto %s\n", interface->name);
	else
		fprintf(fd, "allow-hotplug %s\n", interface->name);
	fprintf(fd, "iface %s inet dhcp\n", interface->name);
	if (!empty_str(interface->dhcp_hostname)) {
		fprintf(fd, "\thostname %s\n", interface->dhcp_hostname);
	}

	return 1;
}

/* Write out a SLAAC stanza for the given interface
 */
static int nc_wi_slaac(const struct netcfg_interface *interface, FILE *fd)
{
	if (interface->dhcp == 0)
		fprintf(fd, "\n# The primary network interface\n");
	fprintf(fd, "# This is an autoconfigured IPv6 interface\n");
	if (interface->dhcp == 0) {
		if (!iface_is_hotpluggable(interface->name) && !find_in_stab(interface->name))
			fprintf(fd, "auto %s\n", interface->name);
		else
			fprintf(fd, "allow-hotplug %s\n", interface->name);
	}

	fprintf(fd, "iface %s inet6 auto\n", interface->name);
/*	fprintf(fd, "\t# Activate RFC 4941 privacy extensions for outgoing connections. The\n");
	fprintf(fd, "\t# machine will still be reachable via its EUI-64 interface identifier.\n");
	fprintf(fd, "\tprivext 2\n");*/

	return 1;
}

/* Write out a static IPv4 config stanza for the given interface
 */
static int nc_wi_static_ipv4(const struct netcfg_interface *interface, FILE *fd)
{
	fprintf(fd, "\n# The primary network interface\n");
	if (!iface_is_hotpluggable(interface->name) && !find_in_stab(interface->name))
		fprintf(fd, "auto %s\n", interface->name);
	else
		fprintf(fd, "allow-hotplug %s\n", interface->name);
	fprintf(fd, "iface %s inet static\n", interface->name);
	fprintf(fd, "\taddress %s/%i\n", interface->ipaddress,
	        empty_str(interface->pointopoint) ? interface->masklen : 32);
	if (!empty_str(interface->gateway))
		fprintf(fd, "\tgateway %s\n",
		        empty_str(interface->pointopoint) ? interface->gateway : interface->pointopoint);
	if (!empty_str(interface->pointopoint))
		fprintf(fd, "\tpointopoint %s\n", interface->pointopoint);

	return 1;
}

/* Write out a static IPv6 config stanza for the given interface
 */
static int nc_wi_static_ipv6(const struct netcfg_interface *interface, FILE *fd)
{
	fprintf(fd, "\n# The primary network interface\n");
	if (!iface_is_hotpluggable(interface->name) && !find_in_stab(interface->name))
		fprintf(fd, "auto %s\n", interface->name);
	else
		fprintf(fd, "allow-hotplug %s\n", interface->name);
	fprintf(fd, "iface %s inet6 static\n", interface->name);
	fprintf(fd, "\taddress %s/%i\n", interface->ipaddress, interface->masklen);
	if (!empty_str(interface->gateway))
		fprintf(fd, "\tgateway %s\n", interface->gateway);

	return 1;
}

/* The main function for writing things to INTERFACES_FILE (aka
 * /etc/network/interfaces).
 *
 * In principle, this function is very simple: just examine the interface
 * we've been passed, and call out to the relevant private helper function. 
 * In practice...
 *
 * Takes the interface struct to write out.  If you pass NULL, the file gets
 * deleted and a helpful comment header gets written.
 *
 * Returns a true/false boolean representing "did everything go OK"; if 0 is
 * returned, the interfaces file will not have been modified, and errno will
 * contain the details.
 */
int netcfg_write_interface(const struct netcfg_interface *interface)
{
	FILE *fd;
	int rv;
	struct stat stat_buf;
	
	if (!interface) {
		di_debug("No interface given; clearing " INTERFACES_FILE);
		rv = unlink(INTERFACES_FILE);
		if (rv < 0 && errno != ENOENT) {
			di_info("Error clearing %s: %s", INTERFACES_FILE, strerror(errno));
			return 0;
		}
	}
	
	fd = file_open(INTERFACES_FILE ".tmp", "w");
	if (!fd) {
		di_warning("Failed to open %s.tmp: %s", INTERFACES_FILE, strerror(errno));
		return 0;
	}

	/* All of this code is to handle the apparently simple task of
	 * copying the existing interfaces file to the tmpfile (if it exists)
	 * so we can add our new stuff to it.  Bloody longwinded way of doing
	 * it, I'm sure you'll agree.
	 */
	rv = stat(INTERFACES_FILE, &stat_buf);
	if (rv < 0 && errno != ENOENT) {
		di_warning("Failed to stat %s: %s", INTERFACES_FILE, strerror(errno));
		unlink(INTERFACES_FILE ".tmp");
		return 0;
	}
	if (rv == 0) {
		char *tmpbuf = malloc(stat_buf.st_size + 1);
		int origfd;
		origfd = open(INTERFACES_FILE, O_RDONLY);
		if (origfd < 0) {
			di_warning("Failed to open %s: %s", INTERFACES_FILE, strerror(errno));
			fclose(fd);
			unlink(INTERFACES_FILE ".tmp");
			free(tmpbuf);
			return 0;
		}
		rv = read(origfd, tmpbuf, stat_buf.st_size);
		if (rv < 0) {
			di_warning("Failed to read %s: %s", INTERFACES_FILE, strerror(errno));
			fclose(fd);
			unlink(INTERFACES_FILE ".tmp");
			free(tmpbuf);
			close(origfd);
			return 0;
		}
		if (rv != stat_buf.st_size) {
			di_warning("Short read on %s", INTERFACES_FILE);
			fclose(fd);
			unlink(INTERFACES_FILE ".tmp");
			free(tmpbuf);
			close(origfd);
			return 0;
		}
		rv = fwrite(tmpbuf, sizeof(char), stat_buf.st_size, fd);
		if (rv != (int)stat_buf.st_size) {
			di_warning("Short write on %s.tmp", INTERFACES_FILE);
			fclose(fd);
			unlink(INTERFACES_FILE ".tmp");
			free(tmpbuf);
			close(origfd);
			return 0;
		}
		free(tmpbuf);
		close(origfd);
	}
		
	
	/* Thank $DEITY all that's out of the way... now we can write a
	 * freaking interfaces file entry */
	rv = 1;

	if (!interface) {
		di_debug("Writing informative header");
		rv = nc_wi_header(fd);
	} else if (interface->loopback == 1) {
		di_debug("Writing loopback interface");
		rv = nc_wi_loopback(interface, fd);
	} else if (interface->dhcp == 1 || interface->slaac == 1) {
		if (interface->dhcp == 1) {
			di_debug("Writing DHCP stanza for %s", interface->name);
			rv = nc_wi_dhcp(interface, fd);
		}
		if (interface->slaac == 1) {
			di_debug("Writing SLAAC stanza for %s", interface->name);
			rv = nc_wi_slaac(interface, fd);
		}
	} else if (interface->address_family == AF_INET) {
		di_debug("Writing static IPv4 stanza for %s", interface->name);
		rv = nc_wi_static_ipv4(interface, fd);
	} else if (interface->address_family == AF_INET6) {
		di_debug("Writing static IPv6 stanza for %s", interface->name);
		rv = nc_wi_static_ipv6(interface, fd);
	}
	
	if (rv && interface && is_wireless_iface(interface->name)) {
		di_debug("Writing wireless options for %s", interface->name);
		rv = nc_wi_wireless_options(interface, fd);
	}

	if (rv) {
		di_debug("Success!");
		rename(INTERFACES_FILE ".tmp", INTERFACES_FILE);
	}

	fclose(fd);
	unlink(INTERFACES_FILE ".tmp");
	return rv;
}