1/*
2 * namespace.c
3 *
4 *		This program is free software; you can redistribute it and/or
5 *		modify it under the terms of the GNU General Public License
6 *		as published by the Free Software Foundation; either version
7 *		2 of the License, or (at your option) any later version.
8 */
9
10#include <fcntl.h>
11#include <dirent.h>
12#include <limits.h>
13
14#include "utils.h"
15#include "namespace.h"
16
17static void bind_etc(const char *name)
18{
19	char etc_netns_path[PATH_MAX];
20	char netns_name[PATH_MAX];
21	char etc_name[PATH_MAX];
22	struct dirent *entry;
23	DIR *dir;
24
25	snprintf(etc_netns_path, sizeof(etc_netns_path), "%s/%s", NETNS_ETC_DIR, name);
26	dir = opendir(etc_netns_path);
27	if (!dir)
28		return;
29
30	while ((entry = readdir(dir)) != NULL) {
31		if (strcmp(entry->d_name, ".") == 0)
32			continue;
33		if (strcmp(entry->d_name, "..") == 0)
34			continue;
35		snprintf(netns_name, sizeof(netns_name), "%s/%s", etc_netns_path, entry->d_name);
36		snprintf(etc_name, sizeof(etc_name), "/etc/%s", entry->d_name);
37		if (mount(netns_name, etc_name, "none", MS_BIND, NULL) < 0) {
38			fprintf(stderr, "Bind %s -> %s failed: %s\n",
39				netns_name, etc_name, strerror(errno));
40		}
41	}
42	closedir(dir);
43}
44
45int netns_switch(char *name)
46{
47	char net_path[PATH_MAX];
48	int netns;
49
50	snprintf(net_path, sizeof(net_path), "%s/%s", NETNS_RUN_DIR, name);
51	netns = open(net_path, O_RDONLY | O_CLOEXEC);
52	if (netns < 0) {
53		fprintf(stderr, "Cannot open network namespace \"%s\": %s\n",
54			name, strerror(errno));
55		return -1;
56	}
57
58	if (setns(netns, CLONE_NEWNET) < 0) {
59		fprintf(stderr, "setting the network namespace \"%s\" failed: %s\n",
60			name, strerror(errno));
61		close(netns);
62		return -1;
63	}
64	close(netns);
65
66	if (unshare(CLONE_NEWNS) < 0) {
67		fprintf(stderr, "unshare failed: %s\n", strerror(errno));
68		return -1;
69	}
70	/* Don't let any mounts propagate back to the parent */
71	if (mount("", "/", "none", MS_SLAVE | MS_REC, NULL)) {
72		fprintf(stderr, "\"mount --make-rslave /\" failed: %s\n",
73			strerror(errno));
74		return -1;
75	}
76	/* Mount a version of /sys that describes the network namespace */
77	if (umount2("/sys", MNT_DETACH) < 0) {
78		fprintf(stderr, "umount of /sys failed: %s\n", strerror(errno));
79		return -1;
80	}
81	if (mount(name, "/sys", "sysfs", 0, NULL) < 0) {
82		fprintf(stderr, "mount of /sys failed: %s\n",strerror(errno));
83		return -1;
84	}
85
86	/* Setup bind mounts for config files in /etc */
87	bind_etc(name);
88	return 0;
89}
90
91int netns_get_fd(const char *name)
92{
93	char pathbuf[PATH_MAX];
94	const char *path, *ptr;
95
96	path = name;
97	ptr = strchr(name, '/');
98	if (!ptr) {
99		snprintf(pathbuf, sizeof(pathbuf), "%s/%s",
100			NETNS_RUN_DIR, name );
101		path = pathbuf;
102	}
103	return open(path, O_RDONLY);
104}
105
106int netns_foreach(int (*func)(char *nsname, void *arg), void *arg)
107{
108	DIR *dir;
109	struct dirent *entry;
110
111	dir = opendir(NETNS_RUN_DIR);
112	if (!dir)
113		return -1;
114
115	while ((entry = readdir(dir)) != NULL) {
116		if (strcmp(entry->d_name, ".") == 0)
117			continue;
118		if (strcmp(entry->d_name, "..") == 0)
119			continue;
120		if (func(entry->d_name, arg))
121			break;
122	}
123
124	closedir(dir);
125	return 0;
126}
127